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SHA1 Hash:f3d4a2db535a12c11b4ab28eba94421ce1880d7c
Date: 2009-11-23 13:21:26
User: drh
Comment:Update the SQLite used internally to the first 3.6.21 release candidate.
Timelines: ancestors | descendants | both | trunk
Other Links: files | ZIP archive | manifest

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Modified src/sqlite3.c from [56de1fb10a] to [bb900ede45].

@@ -1,8 +1,8 @@
 /******************************************************************************
 ** This file is an amalgamation of many separate C source files from SQLite
-** version 3.6.20.  By combining all the individual C code files into this
+** version 3.6.21.  By combining all the individual C code files into this
 ** single large file, the entire code can be compiled as a one translation
 ** unit.  This allows many compilers to do optimizations that would not be
 ** possible if the files were compiled separately.  Performance improvements
 ** of 5% are more are commonly seen when SQLite is compiled as a single
 ** translation unit.
@@ -91,12 +91,10 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 **
 ** This file defines various limits of what SQLite can process.
-**
-** @(#) $Id: sqliteLimit.h,v 1.10 2009/01/10 16:15:09 danielk1977 Exp $
 */
 
 /*
 ** The maximum length of a TEXT or BLOB in bytes.   This also
 ** limits the size of a row in a table or index.
@@ -277,15 +275,11 @@
 ** A value of 1 means that a trigger program will not be able to itself
 ** fire any triggers. A value of 0 means that no trigger programs at all
 ** may be executed.
 */
 #ifndef SQLITE_MAX_TRIGGER_DEPTH
-#if defined(SQLITE_SMALL_STACK)
-# define SQLITE_MAX_TRIGGER_DEPTH 10
-#else
-# define SQLITE_MAX_TRIGGER_DEPTH 1000
-#endif
+# define SQLITE_MAX_TRIGGER_DEPTH 1000
 #endif
 
 /************** End of sqliteLimit.h *****************************************/
 /************** Continuing where we left off in sqliteInt.h ******************/
 
@@ -647,13 +641,13 @@
 ** [sqlite3_libversion_number()], [sqlite3_sourceid()],
 ** [sqlite_version()] and [sqlite_source_id()].
 **
 ** Requirements: [H10011] [H10014]
 */
-#define SQLITE_VERSION        "3.6.20"
-#define SQLITE_VERSION_NUMBER 3006020
-#define SQLITE_SOURCE_ID      "2009-11-04 23:02:52 f1c09acaca3e205acf5b077c9b2d0fe35f035c1e"
+#define SQLITE_VERSION        "3.6.21"
+#define SQLITE_VERSION_NUMBER 3006021
+#define SQLITE_SOURCE_ID      "2009-11-23 13:17:27 39214aee6553db76309851e7aa74fcc02d4f59b7"
 
 /*
 ** CAPI3REF: Run-Time Library Version Numbers {H10020} <S60100>
 ** KEYWORDS: sqlite3_version
 **
@@ -6316,12 +6310,10 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 ** This is the header file for the generic hash-table implemenation
 ** used in SQLite.
-**
-** $Id: hash.h,v 1.15 2009/05/02 13:29:38 drh Exp $
 */
 #ifndef _SQLITE_HASH_H_
 #define _SQLITE_HASH_H_
 
 /* Forward declarations of structures. */
@@ -6920,12 +6912,10 @@
 **
 *************************************************************************
 ** This header file defines the interface that the sqlite B-Tree file
 ** subsystem.  See comments in the source code for a detailed description
 ** of what each interface routine does.
-**
-** @(#) $Id: btree.h,v 1.120 2009/07/22 00:35:24 drh Exp $
 */
 #ifndef _BTREE_H_
 #define _BTREE_H_
 
 /* TODO: This definition is just included so other modules compile. It
@@ -7058,10 +7048,11 @@
   int wrFlag,                          /* 1 for writing.  0 for read-only */
   struct KeyInfo*,                     /* First argument to compare function */
   BtCursor *pCursor                    /* Space to write cursor structure */
 );
 SQLITE_PRIVATE int sqlite3BtreeCursorSize(void);
+SQLITE_PRIVATE void sqlite3BtreeCursorZero(BtCursor*);
 
 SQLITE_PRIVATE int sqlite3BtreeCloseCursor(BtCursor*);
 SQLITE_PRIVATE int sqlite3BtreeMovetoUnpacked(
   BtCursor*,
   UnpackedRecord *pUnKey,
@@ -7169,12 +7160,10 @@
 ** Header file for the Virtual DataBase Engine (VDBE)
 **
 ** This header defines the interface to the virtual database engine
 ** or VDBE.  The VDBE implements an abstract machine that runs a
 ** simple program to access and modify the underlying database.
-**
-** $Id: vdbe.h,v 1.142 2009/07/24 17:58:53 danielk1977 Exp $
 */
 #ifndef _SQLITE_VDBE_H_
 #define _SQLITE_VDBE_H_
 
 /*
@@ -7198,11 +7187,11 @@
 ** as an instance of the following structure:
 */
 struct VdbeOp {
   u8 opcode;          /* What operation to perform */
   signed char p4type; /* One of the P4_xxx constants for p4 */
-  u8 opflags;         /* Not currently used */
+  u8 opflags;         /* Mask of the OPFLG_* flags in opcodes.h */
   u8 p5;              /* Fifth parameter is an unsigned character */
   int p1;             /* First operand */
   int p2;             /* Second parameter (often the jump destination) */
   int p3;             /* The third parameter */
   union {             /* fourth parameter */
@@ -7476,26 +7465,27 @@
 #define OPFLG_JUMP            0x0001  /* jump:  P2 holds jmp target */
 #define OPFLG_OUT2_PRERELEASE 0x0002  /* out2-prerelease: */
 #define OPFLG_IN1             0x0004  /* in1:   P1 is an input */
 #define OPFLG_IN2             0x0008  /* in2:   P2 is an input */
 #define OPFLG_IN3             0x0010  /* in3:   P3 is an input */
-#define OPFLG_OUT3            0x0020  /* out3:  P3 is an output */
+#define OPFLG_OUT2            0x0020  /* out2:  P2 is an output */
+#define OPFLG_OUT3            0x0040  /* out3:  P3 is an output */
 #define OPFLG_INITIALIZER {\
-/*   0 */ 0x00, 0x01, 0x01, 0x04, 0x04, 0x10, 0x00, 0x02,\
-/*   8 */ 0x02, 0x02, 0x02, 0x02, 0x00, 0x00, 0x04, 0x04,\
-/*  16 */ 0x00, 0x00, 0x00, 0x04, 0x04, 0x05, 0x04, 0x00,\
+/*   0 */ 0x00, 0x01, 0x05, 0x04, 0x04, 0x10, 0x00, 0x02,\
+/*   8 */ 0x02, 0x02, 0x02, 0x02, 0x00, 0x00, 0x24, 0x24,\
+/*  16 */ 0x00, 0x00, 0x00, 0x24, 0x04, 0x05, 0x04, 0x00,\
 /*  24 */ 0x00, 0x01, 0x05, 0x05, 0x00, 0x00, 0x00, 0x02,\
 /*  32 */ 0x00, 0x00, 0x00, 0x02, 0x10, 0x00, 0x00, 0x00,\
 /*  40 */ 0x00, 0x00, 0x00, 0x11, 0x11, 0x11, 0x11, 0x08,\
 /*  48 */ 0x11, 0x11, 0x11, 0x11, 0x02, 0x02, 0x00, 0x00,\
 /*  56 */ 0x00, 0x00, 0x00, 0x00, 0x02, 0x00, 0x01, 0x01,\
-/*  64 */ 0x01, 0x01, 0x01, 0x08, 0x2c, 0x2c, 0x00, 0x02,\
-/*  72 */ 0x11, 0x05, 0x05, 0x15, 0x15, 0x15, 0x15, 0x15,\
-/*  80 */ 0x15, 0x11, 0x2c, 0x2c, 0x2c, 0x2c, 0x2c, 0x2c,\
-/*  88 */ 0x2c, 0x2c, 0x2c, 0x2c, 0x02, 0x04, 0x02, 0x00,\
+/*  64 */ 0x01, 0x01, 0x01, 0x08, 0x4c, 0x4c, 0x00, 0x02,\
+/*  72 */ 0x01, 0x05, 0x05, 0x15, 0x15, 0x15, 0x15, 0x15,\
+/*  80 */ 0x15, 0x01, 0x4c, 0x4c, 0x4c, 0x4c, 0x4c, 0x4c,\
+/*  88 */ 0x4c, 0x4c, 0x4c, 0x4c, 0x02, 0x24, 0x02, 0x00,\
 /*  96 */ 0x02, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
-/* 104 */ 0x08, 0x21, 0x15, 0x01, 0x02, 0x00, 0x01, 0x08,\
+/* 104 */ 0x0c, 0x45, 0x15, 0x01, 0x02, 0x00, 0x01, 0x08,\
 /* 112 */ 0x05, 0x05, 0x05, 0x00, 0x00, 0x00, 0x01, 0x00,\
 /* 120 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x01,\
 /* 128 */ 0x00, 0x00, 0x02, 0x02, 0x00, 0x00, 0x00, 0x00,\
 /* 136 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x04, 0x04,\
 /* 144 */ 0x04, 0x04,}
@@ -7511,10 +7501,11 @@
 SQLITE_PRIVATE int sqlite3VdbeAddOp0(Vdbe*,int);
 SQLITE_PRIVATE int sqlite3VdbeAddOp1(Vdbe*,int,int);
 SQLITE_PRIVATE int sqlite3VdbeAddOp2(Vdbe*,int,int,int);
 SQLITE_PRIVATE int sqlite3VdbeAddOp3(Vdbe*,int,int,int,int);
 SQLITE_PRIVATE int sqlite3VdbeAddOp4(Vdbe*,int,int,int,int,const char *zP4,int);
+SQLITE_PRIVATE int sqlite3VdbeAddOp4Int(Vdbe*,int,int,int,int,int);
 SQLITE_PRIVATE int sqlite3VdbeAddOpList(Vdbe*, int nOp, VdbeOpList const *aOp);
 SQLITE_PRIVATE void sqlite3VdbeChangeP1(Vdbe*, int addr, int P1);
 SQLITE_PRIVATE void sqlite3VdbeChangeP2(Vdbe*, int addr, int P2);
 SQLITE_PRIVATE void sqlite3VdbeChangeP3(Vdbe*, int addr, int P3);
 SQLITE_PRIVATE void sqlite3VdbeChangeP5(Vdbe*, u8 P5);
@@ -7579,12 +7570,10 @@
 **
 *************************************************************************
 ** This header file defines the interface that the sqlite page cache
 ** subsystem.  The page cache subsystem reads and writes a file a page
 ** at a time and provides a journal for rollback.
-**
-** @(#) $Id: pager.h,v 1.104 2009/07/24 19:01:19 drh Exp $
 */
 
 #ifndef _PAGER_H_
 #define _PAGER_H_
 
@@ -7750,12 +7739,10 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 ** This header file defines the interface that the sqlite page cache
 ** subsystem.
-**
-** @(#) $Id: pcache.h,v 1.20 2009/07/25 11:46:49 danielk1977 Exp $
 */
 
 #ifndef _PCACHE_H_
 
 typedef struct PgHdr PgHdr;
@@ -7918,12 +7905,10 @@
 ** "os.c") attempt to abstract the underlying operating system so that
 ** the SQLite library will work on both POSIX and windows systems.
 **
 ** This header file is #include-ed by sqliteInt.h and thus ends up
 ** being included by every source file.
-**
-** $Id: os.h,v 1.108 2009/02/05 16:31:46 drh Exp $
 */
 #ifndef _SQLITE_OS_H_
 #define _SQLITE_OS_H_
 
 /*
@@ -8198,12 +8183,10 @@
 ** better organized.
 **
 ** NOTE:  source files should *not* #include this header file directly.
 ** Source files should #include the sqliteInt.h file and let that file
 ** include this one indirectly.
-**
-** $Id: mutex.h,v 1.9 2008/10/07 15:25:48 drh Exp $
 */
 
 
 /*
 ** Figure out what version of the code to use.  The choices are
@@ -8576,10 +8559,11 @@
 #define SQLITE_FUNC_CASE     0x02 /* Case-sensitive LIKE-type function */
 #define SQLITE_FUNC_EPHEM    0x04 /* Ephemeral.  Delete with VDBE */
 #define SQLITE_FUNC_NEEDCOLL 0x08 /* sqlite3GetFuncCollSeq() might be called */
 #define SQLITE_FUNC_PRIVATE  0x10 /* Allowed for internal use only */
 #define SQLITE_FUNC_COUNT    0x20 /* Built-in count(*) aggregate */
+#define SQLITE_FUNC_COALESCE 0x40 /* Built-in coalesce() or ifnull() function */
 
 /*
 ** The following three macros, FUNCTION(), LIKEFUNC() and AGGREGATE() are
 ** used to create the initializers for the FuncDef structures.
 **
@@ -10290,10 +10274,13 @@
 SQLITE_PRIVATE void sqlite3CloseSavepoints(sqlite3 *);
 SQLITE_PRIVATE int sqlite3ExprIsConstant(Expr*);
 SQLITE_PRIVATE int sqlite3ExprIsConstantNotJoin(Expr*);
 SQLITE_PRIVATE int sqlite3ExprIsConstantOrFunction(Expr*);
 SQLITE_PRIVATE int sqlite3ExprIsInteger(Expr*, int*);
+SQLITE_PRIVATE int sqlite3ExprCanBeNull(const Expr*);
+SQLITE_PRIVATE void sqlite3ExprCodeIsNullJump(Vdbe*, const Expr*, int, int);
+SQLITE_PRIVATE int sqlite3ExprNeedsNoAffinityChange(const Expr*, char);
 SQLITE_PRIVATE int sqlite3IsRowid(const char*);
 SQLITE_PRIVATE void sqlite3GenerateRowDelete(Parse*, Table*, int, int, int, Trigger *, int);
 SQLITE_PRIVATE void sqlite3GenerateRowIndexDelete(Parse*, Table*, int, int*);
 SQLITE_PRIVATE int sqlite3GenerateIndexKey(Parse*, Index*, int, int, int);
 SQLITE_PRIVATE void sqlite3GenerateConstraintChecks(Parse*,Table*,int,int,
@@ -10461,10 +10448,11 @@
 SQLITE_PRIVATE char *sqlite3Utf8to16(sqlite3 *, u8, char *, int, int *);
 #endif
 SQLITE_PRIVATE int sqlite3ValueFromExpr(sqlite3 *, Expr *, u8, u8, sqlite3_value **);
 SQLITE_PRIVATE void sqlite3ValueApplyAffinity(sqlite3_value *, u8, u8);
 #ifndef SQLITE_AMALGAMATION
+SQLITE_PRIVATE const unsigned char sqlite3OpcodeProperty[];
 SQLITE_PRIVATE const unsigned char sqlite3UpperToLower[];
 SQLITE_PRIVATE const unsigned char sqlite3CtypeMap[];
 SQLITE_PRIVATE SQLITE_WSD struct Sqlite3Config sqlite3Config;
 SQLITE_PRIVATE SQLITE_WSD FuncDefHash sqlite3GlobalFunctions;
 SQLITE_PRIVATE int sqlite3PendingByte;
@@ -10702,11 +10690,10 @@
 *************************************************************************
 **
 ** This file contains definitions of global variables and contants.
 */
 
-
 /* An array to map all upper-case characters into their corresponding
 ** lower-case character.
 **
 ** SQLite only considers US-ASCII (or EBCDIC) characters.  We do not
 ** handle case conversions for the UTF character set since the tables
@@ -10758,10 +10745,11 @@
 **   isalpha()                        0x02
 **   isdigit()                        0x04
 **   isalnum()                        0x06
 **   isxdigit()                       0x08
 **   toupper()                        0x20
+**   SQLite identifier character      0x40
 **
 ** Bit 0x20 is set if the mapped character requires translation to upper
 ** case. i.e. if the character is a lower-case ASCII character.
 ** If x is a lower-case ASCII character, then its upper-case equivalent
 ** is (x - 0x20). Therefore toupper() can be implemented as:
@@ -10769,50 +10757,55 @@
 **   (x & ~(map[x]&0x20))
 **
 ** Standard function tolower() is implemented using the sqlite3UpperToLower[]
 ** array. tolower() is used more often than toupper() by SQLite.
 **
+** Bit 0x40 is set if the character non-alphanumeric and can be used in an
+** SQLite identifier.  Identifiers are alphanumerics, "_", "$", and any
+** non-ASCII UTF character. Hence the test for whether or not a character is
+** part of an identifier is 0x46.
+**
 ** SQLite's versions are identical to the standard versions assuming a
 ** locale of "C". They are implemented as macros in sqliteInt.h.
 */
 #ifdef SQLITE_ASCII
 SQLITE_PRIVATE const unsigned char sqlite3CtypeMap[256] = {
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 00..07    ........ */
   0x00, 0x01, 0x01, 0x01, 0x01, 0x01, 0x00, 0x00,  /* 08..0f    ........ */
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 10..17    ........ */
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 18..1f    ........ */
-  0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 20..27     !"#$%&' */
+  0x01, 0x00, 0x00, 0x00, 0x40, 0x00, 0x00, 0x00,  /* 20..27     !"#$%&' */
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 28..2f    ()*+,-./ */
   0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c,  /* 30..37    01234567 */
   0x0c, 0x0c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 38..3f    89:;<=>? */
 
   0x00, 0x0a, 0x0a, 0x0a, 0x0a, 0x0a, 0x0a, 0x02,  /* 40..47    @ABCDEFG */
   0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,  /* 48..4f    HIJKLMNO */
   0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,  /* 50..57    PQRSTUVW */
-  0x02, 0x02, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 58..5f    XYZ[\]^_ */
+  0x02, 0x02, 0x02, 0x00, 0x00, 0x00, 0x00, 0x40,  /* 58..5f    XYZ[\]^_ */
   0x00, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x22,  /* 60..67    `abcdefg */
   0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22,  /* 68..6f    hijklmno */
   0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22,  /* 70..77    pqrstuvw */
   0x22, 0x22, 0x22, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 78..7f    xyz{|}~. */
 
-  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 80..87    ........ */
-  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 88..8f    ........ */
-  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 90..97    ........ */
-  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 98..9f    ........ */
-  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* a0..a7    ........ */
-  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* a8..af    ........ */
-  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* b0..b7    ........ */
-  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* b8..bf    ........ */
-
-  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* c0..c7    ........ */
-  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* c8..cf    ........ */
-  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* d0..d7    ........ */
-  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* d8..df    ........ */
-  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* e0..e7    ........ */
-  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* e8..ef    ........ */
-  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* f0..f7    ........ */
-  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00   /* f8..ff    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* 80..87    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* 88..8f    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* 90..97    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* 98..9f    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* a0..a7    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* a8..af    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* b0..b7    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* b8..bf    ........ */
+
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* c0..c7    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* c8..cf    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* d0..d7    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* d8..df    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* e0..e7    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* e8..ef    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* f0..f7    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40   /* f8..ff    ........ */
 };
 #endif
 
 
 
@@ -10877,10 +10870,18 @@
 ** Changing the pending byte during operating results in undefined
 ** and dileterious behavior.
 */
 SQLITE_PRIVATE int sqlite3PendingByte = 0x40000000;
 
+/*
+** Properties of opcodes.  The OPFLG_INITIALIZER macro is
+** created by mkopcodeh.awk during compilation.  Data is obtained
+** from the comments following the "case OP_xxxx:" statements in
+** the vdbe.c file.
+*/
+SQLITE_PRIVATE const unsigned char sqlite3OpcodeProperty[] = OPFLG_INITIALIZER;
+
 /************** End of global.c **********************************************/
 /************** Begin file status.c ******************************************/
 /*
 ** 2008 June 18
 **
@@ -10893,12 +10894,10 @@
 **
 *************************************************************************
 **
 ** This module implements the sqlite3_status() interface and related
 ** functionality.
-**
-** $Id: status.c,v 1.9 2008/09/02 00:52:52 drh Exp $
 */
 
 /*
 ** Variables in which to record status information.
 */
@@ -11020,12 +11019,10 @@
 ** functions for SQLite.
 **
 ** There is only one exported symbol in this file - the function
 ** sqlite3RegisterDateTimeFunctions() found at the bottom of the file.
 ** All other code has file scope.
-**
-** $Id: date.c,v 1.107 2009/05/03 20:23:53 drh Exp $
 **
 ** SQLite processes all times and dates as Julian Day numbers.  The
 ** dates and times are stored as the number of days since noon
 ** in Greenwich on November 24, 4714 B.C. according to the Gregorian
 ** calendar system.
@@ -12125,12 +12122,10 @@
 **
 ******************************************************************************
 **
 ** This file contains OS interface code that is common to all
 ** architectures.
-**
-** $Id: os.c,v 1.127 2009/07/27 11:41:21 danielk1977 Exp $
 */
 #define _SQLITE_OS_C_ 1
 #undef _SQLITE_OS_C_
 
 /*
@@ -12252,10 +12247,11 @@
   sqlite3_vfs *pVfs,
   const char *zPath,
   int nPathOut,
   char *zPathOut
 ){
+  zPathOut[0] = 0;
   return pVfs->xFullPathname(pVfs, zPath, nPathOut, zPathOut);
 }
 #ifndef SQLITE_OMIT_LOAD_EXTENSION
 SQLITE_PRIVATE void *sqlite3OsDlOpen(sqlite3_vfs *pVfs, const char *zPath){
   return pVfs->xDlOpen(pVfs, zPath);
@@ -12423,14 +12419,10 @@
 **    May you find forgiveness for yourself and forgive others.
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 **
-** $Id: fault.c,v 1.11 2008/09/02 00:52:52 drh Exp $
-*/
-
-/*
 ** This file contains code to support the concept of "benign"
 ** malloc failures (when the xMalloc() or xRealloc() method of the
 ** sqlite3_mem_methods structure fails to allocate a block of memory
 ** and returns 0).
 **
@@ -12521,12 +12513,10 @@
 ** This file contains a no-op memory allocation drivers for use when
 ** SQLITE_ZERO_MALLOC is defined.  The allocation drivers implemented
 ** here always fail.  SQLite will not operate with these drivers.  These
 ** are merely placeholders.  Real drivers must be substituted using
 ** sqlite3_config() before SQLite will operate.
-**
-** $Id: mem0.c,v 1.1 2008/10/28 18:58:20 drh Exp $
 */
 
 /*
 ** This version of the memory allocator is the default.  It is
 ** used when no other memory allocator is specified using compile-time
@@ -12585,12 +12575,10 @@
 ** SQLite will use the standard C-library malloc/realloc/free interface
 ** to obtain the memory it needs.
 **
 ** This file contains implementations of the low-level memory allocation
 ** routines specified in the sqlite3_mem_methods object.
-**
-** $Id: mem1.c,v 1.30 2009/03/23 04:33:33 danielk1977 Exp $
 */
 
 /*
 ** This version of the memory allocator is the default.  It is
 ** used when no other memory allocator is specified using compile-time
@@ -12734,12 +12722,10 @@
 ** information to each allocation in order to help detect and fix memory
 ** leaks and memory usage errors.
 **
 ** This file contains implementations of the low-level memory allocation
 ** routines specified in the sqlite3_mem_methods object.
-**
-** $Id: mem2.c,v 1.45 2009/03/23 04:33:33 danielk1977 Exp $
 */
 
 /*
 ** This version of the memory allocator is used only if the
 ** SQLITE_MEMDEBUG macro is defined
@@ -13183,12 +13169,10 @@
 ** the amount of memory available to SQLite is fixed and cannot
 ** be changed.
 **
 ** This version of the memory allocation subsystem is included
 ** in the build only if SQLITE_ENABLE_MEMSYS3 is defined.
-**
-** $Id: mem3.c,v 1.25 2008/11/19 16:52:44 danielk1977 Exp $
 */
 
 /*
 ** This version of the memory allocator is only built into the library
 ** SQLITE_ENABLE_MEMSYS3 is defined. Defining this symbol does not
@@ -14442,13 +14426,10 @@
 **
 *************************************************************************
 ** This file contains the C functions that implement mutexes.
 **
 ** This file contains code that is common across all mutex implementations.
-
-**
-** $Id: mutex.c,v 1.31 2009/07/16 18:21:18 drh Exp $
 */
 
 #if defined(SQLITE_DEBUG) && !defined(SQLITE_MUTEX_OMIT)
 /*
 ** For debugging purposes, record when the mutex subsystem is initialized
@@ -14609,12 +14590,10 @@
 ** interface.
 **
 ** If compiled with SQLITE_DEBUG, then additional logic is inserted
 ** that does error checking on mutexes to make sure they are being
 ** called correctly.
-**
-** $Id: mutex_noop.c,v 1.3 2008/12/05 17:17:08 drh Exp $
 */
 
 
 #if defined(SQLITE_MUTEX_NOOP) && !defined(SQLITE_DEBUG)
 /*
@@ -14783,12 +14762,10 @@
 **    May you find forgiveness for yourself and forgive others.
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 ** This file contains the C functions that implement mutexes for OS/2
-**
-** $Id: mutex_os2.c,v 1.11 2008/11/22 19:50:54 pweilbacher Exp $
 */
 
 /*
 ** The code in this file is only used if SQLITE_MUTEX_OS2 is defined.
 ** See the mutex.h file for details.
@@ -15058,12 +15035,10 @@
 **    May you find forgiveness for yourself and forgive others.
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 ** This file contains the C functions that implement mutexes for pthreads
-**
-** $Id: mutex_unix.c,v 1.16 2008/12/08 18:19:18 drh Exp $
 */
 
 /*
 ** The code in this file is only used if we are compiling threadsafe
 ** under unix with pthreads.
@@ -15389,12 +15364,10 @@
 **    May you find forgiveness for yourself and forgive others.
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 ** This file contains the C functions that implement mutexes for win32
-**
-** $Id: mutex_w32.c,v 1.18 2009/08/10 03:23:21 shane Exp $
 */
 
 /*
 ** The code in this file is only used if we are compiling multithreaded
 ** on a win32 system.
@@ -15676,12 +15649,10 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 **
 ** Memory allocation functions used throughout sqlite.
-**
-** $Id: malloc.c,v 1.66 2009/07/17 11:44:07 drh Exp $
 */
 
 /*
 ** This routine runs when the memory allocator sees that the
 ** total memory allocation is about to exceed the soft heap
@@ -16382,12 +16353,10 @@
 ** The "printf" code that follows dates from the 1980's.  It is in
 ** the public domain.  The original comments are included here for
 ** completeness.  They are very out-of-date but might be useful as
 ** an historical reference.  Most of the "enhancements" have been backed
 ** out so that the functionality is now the same as standard printf().
-**
-** $Id: printf.c,v 1.104 2009/06/03 01:24:54 drh Exp $
 **
 **************************************************************************
 **
 ** The following modules is an enhanced replacement for the "printf" subroutines
 ** found in the standard C library.  The following enhancements are
@@ -17352,12 +17321,10 @@
 ** This file contains code to implement a pseudo-random number
 ** generator (PRNG) for SQLite.
 **
 ** Random numbers are used by some of the database backends in order
 ** to generate random integer keys for tables or random filenames.
-**
-** $Id: random.c,v 1.29 2008/12/10 19:26:24 drh Exp $
 */
 
 
 /* All threads share a single random number generator.
 ** This structure is the current state of the generator.
@@ -17499,12 +17466,10 @@
 **
 *************************************************************************
 ** This file contains routines used to translate between UTF-8,
 ** UTF-16, UTF-16BE, and UTF-16LE.
 **
-** $Id: utf.c,v 1.73 2009/04/01 18:40:32 drh Exp $
-**
 ** Notes on UTF-8:
 **
 **   Byte-0    Byte-1    Byte-2    Byte-3    Value
 **  0xxxxxxx                                 00000000 00000000 0xxxxxxx
 **  110yyyyy  10xxxxxx                       00000000 00000yyy yyxxxxxx
@@ -17540,12 +17505,10 @@
 ** This is the header file for information that is private to the
 ** VDBE.  This information used to all be at the top of the single
 ** source code file "vdbe.c".  When that file became too big (over
 ** 6000 lines long) it was split up into several smaller files and
 ** this header information was factored out.
-**
-** $Id: vdbeInt.h,v 1.174 2009/06/23 14:15:04 drh Exp $
 */
 #ifndef _VDBEINT_H_
 #define _VDBEINT_H_
 
 /*
@@ -17907,11 +17870,10 @@
 SQLITE_PRIVATE int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*);
 SQLITE_PRIVATE void sqlite3VdbeMemRelease(Mem *p);
 SQLITE_PRIVATE void sqlite3VdbeMemReleaseExternal(Mem *p);
 SQLITE_PRIVATE int sqlite3VdbeMemFinalize(Mem*, FuncDef*);
 SQLITE_PRIVATE const char *sqlite3OpcodeName(int);
-SQLITE_PRIVATE int sqlite3VdbeOpcodeHasProperty(int, int);
 SQLITE_PRIVATE int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
 SQLITE_PRIVATE int sqlite3VdbeCloseStatement(Vdbe *, int);
 SQLITE_PRIVATE void sqlite3VdbeFrameDelete(VdbeFrame*);
 SQLITE_PRIVATE int sqlite3VdbeFrameRestore(VdbeFrame *);
 SQLITE_PRIVATE void sqlite3VdbeMemStoreType(Mem *pMem);
@@ -19574,12 +19536,10 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 ** This is the implementation of generic hash-tables
 ** used in SQLite.
-**
-** $Id: hash.c,v 1.38 2009/05/09 23:29:12 drh Exp $
 */
 
 /* Turn bulk memory into a hash table object by initializing the
 ** fields of the Hash structure.
 **
@@ -20011,12 +19971,10 @@
 **    May you share freely, never taking more than you give.
 **
 ******************************************************************************
 **
 ** This file contains code that is specific to OS/2.
-**
-** $Id: os_os2.c,v 1.63 2008/12/10 19:26:24 drh Exp $
 */
 
 
 #if SQLITE_OS_OS2
 
@@ -20074,12 +20032,10 @@
 ** all of the platform-specific files (os_*.c) and is #included into those
 ** files.
 **
 ** This file should be #included by the os_*.c files only.  It is not a
 ** general purpose header file.
-**
-** $Id: os_common.h,v 1.38 2009/02/24 18:40:50 danielk1977 Exp $
 */
 #ifndef _OS_COMMON_H_
 #define _OS_COMMON_H_
 
 /*
@@ -20136,12 +20092,10 @@
 **
 ******************************************************************************
 **
 ** This file contains inline asm code for retrieving "high-performance"
 ** counters for x86 class CPUs.
-**
-** $Id: hwtime.h,v 1.3 2008/08/01 14:33:15 shane Exp $
 */
 #ifndef _HWTIME_H_
 #define _HWTIME_H_
 
 /*
@@ -21603,12 +21557,10 @@
 ** all of the platform-specific files (os_*.c) and is #included into those
 ** files.
 **
 ** This file should be #included by the os_*.c files only.  It is not a
 ** general purpose header file.
-**
-** $Id: os_common.h,v 1.38 2009/02/24 18:40:50 danielk1977 Exp $
 */
 #ifndef _OS_COMMON_H_
 #define _OS_COMMON_H_
 
 /*
@@ -21665,12 +21617,10 @@
 **
 ******************************************************************************
 **
 ** This file contains inline asm code for retrieving "high-performance"
 ** counters for x86 class CPUs.
-**
-** $Id: hwtime.h,v 1.3 2008/08/01 14:33:15 shane Exp $
 */
 #ifndef _HWTIME_H_
 #define _HWTIME_H_
 
 /*
@@ -24685,10 +24635,23 @@
   rc = ftruncate(((unixFile*)id)->h, (off_t)nByte);
   if( rc ){
     ((unixFile*)id)->lastErrno = errno;
     return SQLITE_IOERR_TRUNCATE;
   }else{
+#ifndef NDEBUG
+    /* If we are doing a normal write to a database file (as opposed to
+    ** doing a hot-journal rollback or a write to some file other than a
+    ** normal database file) and we truncate the file to zero length,
+    ** that effectively updates the change counter.  This might happen
+    ** when restoring a database using the backup API from a zero-length
+    ** source.
+    */
+    if( ((unixFile*)id)->inNormalWrite && nByte==0 ){
+      ((unixFile*)id)->transCntrChng = 1;
+    }
+#endif
+
     return SQLITE_OK;
   }
 }
 
 /*
@@ -27042,12 +27005,10 @@
 ** all of the platform-specific files (os_*.c) and is #included into those
 ** files.
 **
 ** This file should be #included by the os_*.c files only.  It is not a
 ** general purpose header file.
-**
-** $Id: os_common.h,v 1.38 2009/02/24 18:40:50 danielk1977 Exp $
 */
 #ifndef _OS_COMMON_H_
 #define _OS_COMMON_H_
 
 /*
@@ -27104,12 +27065,10 @@
 **
 ******************************************************************************
 **
 ** This file contains inline asm code for retrieving "high-performance"
 ** counters for x86 class CPUs.
-**
-** $Id: hwtime.h,v 1.3 2008/08/01 14:33:15 shane Exp $
 */
 #ifndef _HWTIME_H_
 #define _HWTIME_H_
 
 /*
@@ -29147,12 +29106,10 @@
 ** 5 and 500 set operations per Bitvec object, though the number of sets can
 ** sometimes grow into tens of thousands or larger.  The size of the
 ** Bitvec object is the number of pages in the database file at the
 ** start of a transaction, and is thus usually less than a few thousand,
 ** but can be as large as 2 billion for a really big database.
-**
-** @(#) $Id: bitvec.c,v 1.17 2009/07/25 17:33:26 drh Exp $
 */
 
 /* Size of the Bitvec structure in bytes. */
 #define BITVEC_SZ        (sizeof(void*)*128)  /* 512 on 32bit.  1024 on 64bit */
 
@@ -29536,12 +29493,10 @@
 **    May you find forgiveness for yourself and forgive others.
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 ** This file implements that page cache.
-**
-** @(#) $Id: pcache.c,v 1.47 2009/07/25 11:46:49 danielk1977 Exp $
 */
 
 /*
 ** A complete page cache is an instance of this structure.
 */
@@ -30119,12 +30074,10 @@
 ** This file implements the default page cache implementation (the
 ** sqlite3_pcache interface). It also contains part of the implementation
 ** of the SQLITE_CONFIG_PAGECACHE and sqlite3_release_memory() features.
 ** If the default page cache implementation is overriden, then neither of
 ** these two features are available.
-**
-** @(#) $Id: pcache1.c,v 1.19 2009/07/17 11:44:07 drh Exp $
 */
 
 
 typedef struct PCache1 PCache1;
 typedef struct PgHdr1 PgHdr1;
@@ -30770,19 +30723,11 @@
 
   h = iNew%pCache->nHash;
   pPage->iKey = iNew;
   pPage->pNext = pCache->apHash[h];
   pCache->apHash[h] = pPage;
-
-  /* The xRekey() interface is only used to move pages earlier in the
-  ** database file (in order to move all free pages to the end of the
-  ** file where they can be truncated off.)  Hence, it is not possible
-  ** for the new page number to be greater than the largest previously
-  ** fetched page.  But we retain the following test in case xRekey()
-  ** begins to be used in different ways in the future.
-  */
-  if( NEVER(iNew>pCache->iMaxKey) ){
+  if( iNew>pCache->iMaxKey ){
     pCache->iMaxKey = iNew;
   }
 
   pcache1LeaveMutex();
 }
@@ -30954,12 +30899,10 @@
 ** of the first SMALLEST is O(NlogN).  Second and subsequent SMALLEST
 ** primitives are constant time.  The cost of DESTROY is O(N).
 **
 ** There is an added cost of O(N) when switching between TEST and
 ** SMALLEST primitives.
-**
-** $Id: rowset.c,v 1.7 2009/05/22 01:00:13 drh Exp $
 */
 
 
 /*
 ** Target size for allocation chunks.
@@ -31338,12 +31281,10 @@
 ** atomic commit and rollback through the use of a journal file that
 ** is separate from the database file.  The pager also implements file
 ** locking to prevent two processes from writing the same database
 ** file simultaneously, or one process from reading the database while
 ** another is writing.
-**
-** @(#) $Id: pager.c,v 1.629 2009/08/10 17:48:57 drh Exp $
 */
 #ifndef SQLITE_OMIT_DISKIO
 
 /*
 ** Macros for troubleshooting.  Normally turned off
@@ -32233,14 +32174,14 @@
       return rc;
     }
 
     /* Check that the values read from the page-size and sector-size fields
     ** are within range. To be 'in range', both values need to be a power
-    ** of two greater than or equal to 512, and not greater than their
+    ** of two greater than or equal to 512 or 32, and not greater than their
     ** respective compile time maximum limits.
     */
-    if( iPageSize<512                  || iSectorSize<512
+    if( iPageSize<512                  || iSectorSize<32
      || iPageSize>SQLITE_MAX_PAGE_SIZE || iSectorSize>MAX_SECTOR_SIZE
      || ((iPageSize-1)&iPageSize)!=0   || ((iSectorSize-1)&iSectorSize)!=0
     ){
       /* If the either the page-size or sector-size in the journal-header is
       ** invalid, then the process that wrote the journal-header must have
@@ -32743,28 +32684,28 @@
 ){
   int rc;
   PgHdr *pPg;                   /* An existing page in the cache */
   Pgno pgno;                    /* The page number of a page in journal */
   u32 cksum;                    /* Checksum used for sanity checking */
-  u8 *aData;                    /* Temporary storage for the page */
+  char *aData;                  /* Temporary storage for the page */
   sqlite3_file *jfd;            /* The file descriptor for the journal file */
 
   assert( (isMainJrnl&~1)==0 );      /* isMainJrnl is 0 or 1 */
   assert( (isSavepnt&~1)==0 );       /* isSavepnt is 0 or 1 */
   assert( isMainJrnl || pDone );     /* pDone always used on sub-journals */
   assert( isSavepnt || pDone==0 );   /* pDone never used on non-savepoint */
 
-  aData = (u8*)pPager->pTmpSpace;
+  aData = pPager->pTmpSpace;
   assert( aData );         /* Temp storage must have already been allocated */
 
   /* Read the page number and page data from the journal or sub-journal
   ** file. Return an error code to the caller if an IO error occurs.
   */
   jfd = isMainJrnl ? pPager->jfd : pPager->sjfd;
   rc = read32bits(jfd, *pOffset, &pgno);
   if( rc!=SQLITE_OK ) return rc;
-  rc = sqlite3OsRead(jfd, aData, pPager->pageSize, (*pOffset)+4);
+  rc = sqlite3OsRead(jfd, (u8*)aData, pPager->pageSize, (*pOffset)+4);
   if( rc!=SQLITE_OK ) return rc;
   *pOffset += pPager->pageSize + 4 + isMainJrnl*4;
 
   /* Sanity checking on the page.  This is more important that I originally
   ** thought.  If a power failure occurs while the journal is being written,
@@ -32779,11 +32720,11 @@
     return SQLITE_OK;
   }
   if( isMainJrnl ){
     rc = read32bits(jfd, (*pOffset)-4, &cksum);
     if( rc ) return rc;
-    if( !isSavepnt && pager_cksum(pPager, aData)!=cksum ){
+    if( !isSavepnt && pager_cksum(pPager, (u8*)aData)!=cksum ){
       return SQLITE_DONE;
     }
   }
 
   if( pDone && (rc = sqlite3BitvecSet(pDone, pgno))!=SQLITE_OK ){
@@ -32825,27 +32766,27 @@
   ** Do not attempt to write if database file has never been opened.
   */
   pPg = pager_lookup(pPager, pgno);
   assert( pPg || !MEMDB );
   PAGERTRACE(("PLAYBACK %d page %d hash(%08x) %s\n",
-               PAGERID(pPager), pgno, pager_datahash(pPager->pageSize, aData),
-               (isMainJrnl?"main-journal":"sub-journal")
+           PAGERID(pPager), pgno, pager_datahash(pPager->pageSize, (u8*)aData),
+           (isMainJrnl?"main-journal":"sub-journal")
   ));
   if( (pPager->state>=PAGER_EXCLUSIVE)
    && (pPg==0 || 0==(pPg->flags&PGHDR_NEED_SYNC))
    && isOpen(pPager->fd)
    && !isUnsync
   ){
     i64 ofst = (pgno-1)*(i64)pPager->pageSize;
-    rc = sqlite3OsWrite(pPager->fd, aData, pPager->pageSize, ofst);
+    rc = sqlite3OsWrite(pPager->fd, (u8*)aData, pPager->pageSize, ofst);
     if( pgno>pPager->dbFileSize ){
       pPager->dbFileSize = pgno;
     }
     if( pPager->pBackup ){
       CODEC1(pPager, aData, pgno, 3, rc=SQLITE_NOMEM);
-      sqlite3BackupUpdate(pPager->pBackup, pgno, aData);
-      CODEC1(pPager, aData, pgno, 0, rc=SQLITE_NOMEM);
+      sqlite3BackupUpdate(pPager->pBackup, pgno, (u8*)aData);
+      CODEC2(pPager, aData, pgno, 7, rc=SQLITE_NOMEM, aData);
     }
   }else if( !isMainJrnl && pPg==0 ){
     /* If this is a rollback of a savepoint and data was not written to
     ** the database and the page is not in-memory, there is a potential
     ** problem. When the page is next fetched by the b-tree layer, it
@@ -32876,11 +32817,11 @@
     ** of an internal error resulting in an automatic call to
     ** sqlite3PagerRollback().
     */
     void *pData;
     pData = pPg->pData;
-    memcpy(pData, aData, pPager->pageSize);
+    memcpy(pData, (u8*)aData, pPager->pageSize);
     pPager->xReiniter(pPg);
     if( isMainJrnl && (!isSavepnt || *pOffset<=pPager->journalHdr) ){
       /* If the contents of this page were just restored from the main
       ** journal file, then its content must be as they were when the
       ** transaction was first opened. In this case we can mark the page
@@ -33101,12 +33042,12 @@
 ** master journal pointers within created journal files.
 **
 ** For temporary files the effective sector size is always 512 bytes.
 **
 ** Otherwise, for non-temporary files, the effective sector size is
-** the value returned by the xSectorSize() method rounded up to 512 if
-** it is less than 512, or rounded down to MAX_SECTOR_SIZE if it
+** the value returned by the xSectorSize() method rounded up to 32 if
+** it is less than 32, or rounded down to MAX_SECTOR_SIZE if it
 ** is greater than MAX_SECTOR_SIZE.
 */
 static void setSectorSize(Pager *pPager){
   assert( isOpen(pPager->fd) || pPager->tempFile );
 
@@ -33115,11 +33056,11 @@
     ** may not have been opened yet, in which case the OsSectorSize()
     ** call will segfault.
     */
     pPager->sectorSize = sqlite3OsSectorSize(pPager->fd);
   }
-  if( pPager->sectorSize<512 ){
+  if( pPager->sectorSize<32 ){
     pPager->sectorSize = 512;
   }
   if( pPager->sectorSize>MAX_SECTOR_SIZE ){
     assert( MAX_SECTOR_SIZE>=512 );
     pPager->sectorSize = MAX_SECTOR_SIZE;
@@ -34193,11 +34134,13 @@
     ** than Pager.dbSize, this means sqlite3PagerTruncateImage() was called to
     ** make the file smaller (presumably by auto-vacuum code). Do not write
     ** any such pages to the file.
     **
     ** Also, do not write out any page that has the PGHDR_DONT_WRITE flag
-    ** set (set by sqlite3PagerDontWrite()).
+    ** set (set by sqlite3PagerDontWrite()).  Note that if compiled with
+    ** SQLITE_SECURE_DELETE the PGHDR_DONT_WRITE bit is never set and so
+    ** the second test is always true.
     */
     if( pgno<=pPager->dbSize && 0==(pList->flags&PGHDR_DONT_WRITE) ){
       i64 offset = (pgno-1)*(i64)pPager->pageSize;   /* Offset to write */
       char *pData;                                   /* Data to write */
 
@@ -35702,10 +35645,11 @@
 SQLITE_PRIVATE int sqlite3PagerIswriteable(DbPage *pPg){
   return pPg->flags&PGHDR_DIRTY;
 }
 #endif
 
+#ifndef SQLITE_SECURE_DELETE
 /*
 ** A call to this routine tells the pager that it is not necessary to
 ** write the information on page pPg back to the disk, even though
 ** that page might be marked as dirty.  This happens, for example, when
 ** the page has been added as a leaf of the freelist and so its
@@ -35727,10 +35671,11 @@
 #ifdef SQLITE_CHECK_PAGES
     pPg->pageHash = pager_pagehash(pPg);
 #endif
   }
 }
+#endif /* !defined(SQLITE_SECURE_DELETE) */
 
 /*
 ** This routine is called to increment the value of the database file
 ** change-counter, stored as a 4-byte big-endian integer starting at
 ** byte offset 24 of the pager file.
@@ -35766,11 +35711,11 @@
 #else
 # define DIRECT_MODE isDirectMode
 #endif
 
   assert( pPager->state>=PAGER_RESERVED );
-  if( !pPager->changeCountDone && ALWAYS(pPager->dbSize>0) ){
+  if( !pPager->changeCountDone && pPager->dbSize>0 ){
     PgHdr *pPgHdr;                /* Reference to page 1 */
     u32 change_counter;           /* Initial value of change-counter field */
 
     assert( !pPager->tempFile && isOpen(pPager->fd) );
 
@@ -36419,10 +36364,18 @@
   int rc;                      /* Return code */
   Pgno origPgno;               /* The original page number */
 
   assert( pPg->nRef>0 );
 
+  /* In order to be able to rollback, an in-memory database must journal
+  ** the page we are moving from.
+  */
+  if( MEMDB ){
+    rc = sqlite3PagerWrite(pPg);
+    if( rc ) return rc;
+  }
+
   /* If the page being moved is dirty and has not been saved by the latest
   ** savepoint, then save the current contents of the page into the
   ** sub-journal now. This is required to handle the following scenario:
   **
   **   BEGIN;
@@ -36472,11 +36425,18 @@
   pPg->flags &= ~PGHDR_NEED_SYNC;
   pPgOld = pager_lookup(pPager, pgno);
   assert( !pPgOld || pPgOld->nRef==1 );
   if( pPgOld ){
     pPg->flags |= (pPgOld->flags&PGHDR_NEED_SYNC);
-    sqlite3PcacheDrop(pPgOld);
+    if( MEMDB ){
+      /* Do not discard pages from an in-memory database since we might
+      ** need to rollback later.  Just move the page out of the way. */
+      assert( pPager->dbSizeValid );
+      sqlite3PcacheMove(pPgOld, pPager->dbSize+1);
+    }else{
+      sqlite3PcacheDrop(pPgOld);
+    }
   }
 
   origPgno = pPg->pgno;
   sqlite3PcacheMove(pPg, pgno);
   sqlite3PcacheMakeDirty(pPg);
@@ -36517,22 +36477,16 @@
     sqlite3PagerUnref(pPgHdr);
   }
 
   /*
   ** For an in-memory database, make sure the original page continues
-  ** to exist, in case the transaction needs to roll back.  We allocate
-  ** the page now, instead of at rollback, because we can better deal
-  ** with an out-of-memory error now.  Ticket #3761.
+  ** to exist, in case the transaction needs to roll back.  Use pPgOld
+  ** as the original page since it has already been allocated.
   */
   if( MEMDB ){
-    DbPage *pNew;
-    rc = sqlite3PagerAcquire(pPager, origPgno, &pNew, 1);
-    if( rc!=SQLITE_OK ){
-      sqlite3PcacheMove(pPg, origPgno);
-      return rc;
-    }
-    sqlite3PagerUnref(pNew);
+    sqlite3PcacheMove(pPgOld, origPgno);
+    sqlite3PagerUnref(pPgOld);
   }
 
   return SQLITE_OK;
 }
 #endif
@@ -36655,12 +36609,10 @@
 **    May you find forgiveness for yourself and forgive others.
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 **
-** $Id: btmutex.c,v 1.17 2009/07/20 12:33:33 drh Exp $
-**
 ** This file contains code used to implement mutexes on Btree objects.
 ** This code really belongs in btree.c.  But btree.c is getting too
 ** big and we want to break it down some.  This packaged seemed like
 ** a good breakout.
 */
@@ -36675,12 +36627,10 @@
 **    May you do good and not evil.
 **    May you find forgiveness for yourself and forgive others.
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
-** $Id: btreeInt.h,v 1.52 2009/07/15 17:25:46 drh Exp $
-**
 ** This file implements a external (disk-based) database using BTrees.
 ** For a detailed discussion of BTrees, refer to
 **
 **     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
 **     "Sorting And Searching", pages 473-480. Addison-Wesley
@@ -37660,12 +37610,10 @@
 **    May you do good and not evil.
 **    May you find forgiveness for yourself and forgive others.
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
-** $Id: btree.c,v 1.705 2009/08/10 03:57:58 shane Exp $
-**
 ** This file implements a external (disk-based) database using BTrees.
 ** See the header comment on "btreeInt.h" for additional information.
 ** Including a description of file format and an overview of operation.
 */
 
@@ -40930,12 +40878,12 @@
 **
 ** No checking is done to make sure that page iTable really is the
 ** root page of a b-tree.  If it is not, then the cursor acquired
 ** will not work correctly.
 **
-** It is assumed that the sqlite3BtreeCursorSize() bytes of memory
-** pointed to by pCur have been zeroed by the caller.
+** It is assumed that the sqlite3BtreeCursorZero() has been called
+** on pCur to initialize the memory space prior to invoking this routine.
 */
 static int btreeCursor(
   Btree *p,                              /* The btree */
   int iTable,                            /* Root page of table to open */
   int wrFlag,                            /* 1 to write. 0 read-only */
@@ -41004,11 +40952,23 @@
 ** sufficient storage to hold a cursor.  The BtCursor object is opaque
 ** to users so they cannot do the sizeof() themselves - they must call
 ** this routine.
 */
 SQLITE_PRIVATE int sqlite3BtreeCursorSize(void){
-  return sizeof(BtCursor);
+  return ROUND8(sizeof(BtCursor));
+}
+
+/*
+** Initialize memory that will be converted into a BtCursor object.
+**
+** The simple approach here would be to memset() the entire object
+** to zero.  But it turns out that the apPage[] and aiIdx[] arrays
+** do not need to be zeroed and they are large, so we can save a lot
+** of run-time by skipping the initialization of those elements.
+*/
+SQLITE_PRIVATE void sqlite3BtreeCursorZero(BtCursor *p){
+  memset(p, 0, offsetof(BtCursor, iPage));
 }
 
 /*
 ** Set the cached rowid value of every cursor in the same database file
 ** as pCur and having the same root page number as pCur.  The value is
@@ -45489,12 +45449,10 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 ** This file contains the implementation of the sqlite3_backup_XXX()
 ** API functions and the related features.
-**
-** $Id: backup.c,v 1.19 2009/07/06 19:03:13 drh Exp $
 */
 
 /* Macro to find the minimum of two numeric values.
 */
 #ifndef MIN
@@ -46123,12 +46081,10 @@
 **
 ** This file contains code use to manipulate "Mem" structure.  A "Mem"
 ** stores a single value in the VDBE.  Mem is an opaque structure visible
 ** only within the VDBE.  Interface routines refer to a Mem using the
 ** name sqlite_value
-**
-** $Id: vdbemem.c,v 1.152 2009/07/22 18:07:41 drh Exp $
 */
 
 /*
 ** Call sqlite3VdbeMemExpandBlob() on the supplied value (type Mem*)
 ** P if required.
@@ -46863,13 +46819,10 @@
 SQLITE_PRIVATE int sqlite3MemCompare(const Mem *pMem1, const Mem *pMem2, const CollSeq *pColl){
   int rc;
   int f1, f2;
   int combined_flags;
 
-  /* Interchange pMem1 and pMem2 if the collating sequence specifies
-  ** DESC order.
-  */
   f1 = pMem1->flags;
   f2 = pMem2->flags;
   combined_flags = f1|f2;
   assert( (combined_flags & MEM_RowSet)==0 );
 
@@ -47116,11 +47069,11 @@
     *ppVal = 0;
     return SQLITE_OK;
   }
   op = pExpr->op;
   if( op==TK_REGISTER ){
-    op = pExpr->op2;
+    op = pExpr->op2;  /* This only happens with SQLITE_ENABLE_STAT2 */
   }
 
   if( op==TK_STRING || op==TK_FLOAT || op==TK_INTEGER ){
     pVal = sqlite3ValueNew(db);
     if( pVal==0 ) goto no_mem;
@@ -47229,12 +47182,10 @@
 *************************************************************************
 ** This file contains code used for creating, destroying, and populating
 ** a VDBE (or an "sqlite3_stmt" as it is known to the outside world.)  Prior
 ** to version 2.8.7, all this code was combined into the vdbe.c source file.
 ** But that file was getting too big so this subroutines were split out.
-**
-** $Id: vdbeaux.c,v 1.480 2009/08/08 18:01:08 drh Exp $
 */
 
 
 
 /*
@@ -47412,10 +47363,26 @@
   sqlite3VdbeChangeP4(p, addr, zP4, p4type);
   return addr;
 }
 
 /*
+** Add an opcode that includes the p4 value as an integer.
+*/
+SQLITE_PRIVATE int sqlite3VdbeAddOp4Int(
+  Vdbe *p,            /* Add the opcode to this VM */
+  int op,             /* The new opcode */
+  int p1,             /* The P1 operand */
+  int p2,             /* The P2 operand */
+  int p3,             /* The P3 operand */
+  int p4              /* The P4 operand as an integer */
+){
+  int addr = sqlite3VdbeAddOp3(p, op, p1, p2, p3);
+  sqlite3VdbeChangeP4(p, addr, SQLITE_INT_TO_PTR(p4), P4_INT32);
+  return addr;
+}
+
+/*
 ** Create a new symbolic label for an instruction that has yet to be
 ** coded.  The symbolic label is really just a negative number.  The
 ** label can be used as the P2 value of an operation.  Later, when
 ** the label is resolved to a specific address, the VDBE will scan
 ** through its operation list and change all values of P2 which match
@@ -47586,10 +47553,12 @@
 ** This routine is called once after all opcodes have been inserted.
 **
 ** Variable *pMaxFuncArgs is set to the maximum value of any P2 argument
 ** to an OP_Function, OP_AggStep or OP_VFilter opcode. This is used by
 ** sqlite3VdbeMakeReady() to size the Vdbe.apArg[] array.
+**
+** The Op.opflags field is set on all opcodes.
 */
 static void resolveP2Values(Vdbe *p, int *pMaxFuncArgs){
   int i;
   int nMaxArgs = *pMaxFuncArgs;
   Op *pOp;
@@ -47596,29 +47565,28 @@
   int *aLabel = p->aLabel;
   p->readOnly = 1;
   for(pOp=p->aOp, i=p->nOp-1; i>=0; i--, pOp++){
     u8 opcode = pOp->opcode;
 
+    pOp->opflags = sqlite3OpcodeProperty[opcode];
     if( opcode==OP_Function || opcode==OP_AggStep ){
       if( pOp->p5>nMaxArgs ) nMaxArgs = pOp->p5;
+    }else if( opcode==OP_Transaction && pOp->p2!=0 ){
+      p->readOnly = 0;
 #ifndef SQLITE_OMIT_VIRTUALTABLE
     }else if( opcode==OP_VUpdate ){
       if( pOp->p2>nMaxArgs ) nMaxArgs = pOp->p2;
-#endif
-    }else if( opcode==OP_Transaction && pOp->p2!=0 ){
-      p->readOnly = 0;
-#ifndef SQLITE_OMIT_VIRTUALTABLE
     }else if( opcode==OP_VFilter ){
       int n;
       assert( p->nOp - i >= 3 );
       assert( pOp[-1].opcode==OP_Integer );
       n = pOp[-1].p1;
       if( n>nMaxArgs ) nMaxArgs = n;
 #endif
     }
 
-    if( sqlite3VdbeOpcodeHasProperty(opcode, OPFLG_JUMP) && pOp->p2<0 ){
+    if( (pOp->opflags & OPFLG_JUMP)!=0 && pOp->p2<0 ){
       assert( -1-pOp->p2<p->nLabel );
       pOp->p2 = aLabel[-1-pOp->p2];
     }
   }
   sqlite3DbFree(p->db, p->aLabel);
@@ -47676,11 +47644,11 @@
     for(i=0; i<nOp; i++, pIn++){
       int p2 = pIn->p2;
       VdbeOp *pOut = &p->aOp[i+addr];
       pOut->opcode = pIn->opcode;
       pOut->p1 = pIn->p1;
-      if( p2<0 && sqlite3VdbeOpcodeHasProperty(pOut->opcode, OPFLG_JUMP) ){
+      if( p2<0 && (sqlite3OpcodeProperty[pOut->opcode] & OPFLG_JUMP)!=0 ){
         pOut->p2 = addr + ADDR(p2);
       }else{
         pOut->p2 = p2;
       }
       pOut->p3 = pIn->p3;
@@ -49986,13 +49954,21 @@
   Mem mem1;
 
   pKeyInfo = pPKey2->pKeyInfo;
   mem1.enc = pKeyInfo->enc;
   mem1.db = pKeyInfo->db;
-  mem1.flags = 0;
-  mem1.u.i = 0;  /* not needed, here to silence compiler warning */
-  mem1.zMalloc = 0;
+  /* mem1.flags = 0;  // Will be initialized by sqlite3VdbeSerialGet() */
+  VVA_ONLY( mem1.zMalloc = 0; ) /* Only needed by assert() statements */
+
+  /* Compilers may complain that mem1.u.i is potentially uninitialized.
+  ** We could initialize it, as shown here, to silence those complaints.
+  ** But in fact, mem1.u.i will never actually be used initialized, and doing
+  ** the unnecessary initialization has a measurable negative performance
+  ** impact, since this routine is a very high runner.  And so, we choose
+  ** to ignore the compiler warnings and leave this variable uninitialized.
+  */
+  /*  mem1.u.i = 0;  // not needed, here to silence compiler warning */
 
   idx1 = getVarint32(aKey1, szHdr1);
   d1 = szHdr1;
   if( pPKey2->flags & UNPACKED_IGNORE_ROWID ){
     szHdr1--;
@@ -50012,51 +49988,56 @@
     /* Do the comparison
     */
     rc = sqlite3MemCompare(&mem1, &pPKey2->aMem[i],
                            i<nField ? pKeyInfo->aColl[i] : 0);
     if( rc!=0 ){
-      break;
+      assert( mem1.zMalloc==0 );  /* See comment below */
+
+      /* Invert the result if we are using DESC sort order. */
+      if( pKeyInfo->aSortOrder && i<nField && pKeyInfo->aSortOrder[i] ){
+        rc = -rc;
+      }
+
+      /* If the PREFIX_SEARCH flag is set and all fields except the final
+      ** rowid field were equal, then clear the PREFIX_SEARCH flag and set
+      ** pPKey2->rowid to the value of the rowid field in (pKey1, nKey1).
+      ** This is used by the OP_IsUnique opcode.
+      */
+      if( (pPKey2->flags & UNPACKED_PREFIX_SEARCH) && i==(pPKey2->nField-1) ){
+        assert( idx1==szHdr1 && rc );
+        assert( mem1.flags & MEM_Int );
+        pPKey2->flags &= ~UNPACKED_PREFIX_SEARCH;
+        pPKey2->rowid = mem1.u.i;
+      }
+
+      return rc;
     }
     i++;
   }
 
-  /* No memory allocation is ever used on mem1. */
-  if( NEVER(mem1.zMalloc) ) sqlite3VdbeMemRelease(&mem1);
-
-  /* If the PREFIX_SEARCH flag is set and all fields except the final
-  ** rowid field were equal, then clear the PREFIX_SEARCH flag and set
-  ** pPKey2->rowid to the value of the rowid field in (pKey1, nKey1).
-  ** This is used by the OP_IsUnique opcode.
-  */
-  if( (pPKey2->flags & UNPACKED_PREFIX_SEARCH) && i==(pPKey2->nField-1) ){
-    assert( idx1==szHdr1 && rc );
-    assert( mem1.flags & MEM_Int );
-    pPKey2->flags &= ~UNPACKED_PREFIX_SEARCH;
-    pPKey2->rowid = mem1.u.i;
-  }
-
-  if( rc==0 ){
-    /* rc==0 here means that one of the keys ran out of fields and
-    ** all the fields up to that point were equal. If the UNPACKED_INCRKEY
-    ** flag is set, then break the tie by treating key2 as larger.
-    ** If the UPACKED_PREFIX_MATCH flag is set, then keys with common prefixes
-    ** are considered to be equal.  Otherwise, the longer key is the
-    ** larger.  As it happens, the pPKey2 will always be the longer
-    ** if there is a difference.
-    */
-    if( pPKey2->flags & UNPACKED_INCRKEY ){
-      rc = -1;
-    }else if( pPKey2->flags & UNPACKED_PREFIX_MATCH ){
-      /* Leave rc==0 */
-    }else if( idx1<szHdr1 ){
-      rc = 1;
-    }
-  }else if( pKeyInfo->aSortOrder && i<pKeyInfo->nField
-               && pKeyInfo->aSortOrder[i] ){
-    rc = -rc;
-  }
-
+  /* No memory allocation is ever used on mem1.  Prove this using
+  ** the following assert().  If the assert() fails, it indicates a
+  ** memory leak and a need to call sqlite3VdbeMemRelease(&mem1).
+  */
+  assert( mem1.zMalloc==0 );
+
+  /* rc==0 here means that one of the keys ran out of fields and
+  ** all the fields up to that point were equal. If the UNPACKED_INCRKEY
+  ** flag is set, then break the tie by treating key2 as larger.
+  ** If the UPACKED_PREFIX_MATCH flag is set, then keys with common prefixes
+  ** are considered to be equal.  Otherwise, the longer key is the
+  ** larger.  As it happens, the pPKey2 will always be the longer
+  ** if there is a difference.
+  */
+  assert( rc==0 );
+  if( pPKey2->flags & UNPACKED_INCRKEY ){
+    rc = -1;
+  }else if( pPKey2->flags & UNPACKED_PREFIX_MATCH ){
+    /* Leave rc==0 */
+  }else if( idx1<szHdr1 ){
+    rc = 1;
+  }
   return rc;
 }
 
 
 /*
@@ -50272,12 +50253,10 @@
 **
 *************************************************************************
 **
 ** This file contains code use to implement APIs that are part of the
 ** VDBE.
-**
-** $Id: vdbeapi.c,v 1.167 2009/06/25 01:47:12 drh Exp $
 */
 
 #ifndef SQLITE_OMIT_DEPRECATED
 /*
 ** Return TRUE (non-zero) of the statement supplied as an argument needs
@@ -51528,12 +51507,10 @@
 ** Various scripts scan this source file in order to generate HTML
 ** documentation, headers files, or other derived files.  The formatting
 ** of the code in this file is, therefore, important.  See other comments
 ** in this file for details.  If in doubt, do not deviate from existing
 ** commenting and indentation practices when changing or adding code.
-**
-** $Id: vdbe.c,v 1.874 2009/07/24 17:58:53 danielk1977 Exp $
 */
 
 /*
 ** The following global variable is incremented every time a cursor
 ** moves, either by the OP_SeekXX, OP_Next, or OP_Prev opcodes.  The test
@@ -51657,27 +51634,10 @@
     pMem->type = SQLITE_BLOB;
   }
 }
 
 /*
-** Properties of opcodes.  The OPFLG_INITIALIZER macro is
-** created by mkopcodeh.awk during compilation.  Data is obtained
-** from the comments following the "case OP_xxxx:" statements in
-** this file.
-*/
-static const unsigned char opcodeProperty[] = OPFLG_INITIALIZER;
-
-/*
-** Return true if an opcode has any of the OPFLG_xxx properties
-** specified by mask.
-*/
-SQLITE_PRIVATE int sqlite3VdbeOpcodeHasProperty(int opcode, int mask){
-  assert( opcode>0 && opcode<(int)sizeof(opcodeProperty) );
-  return (opcodeProperty[opcode]&mask)!=0;
-}
-
-/*
 ** Allocate VdbeCursor number iCur.  Return a pointer to it.  Return NULL
 ** if we run out of memory.
 */
 static VdbeCursor *allocateCursor(
   Vdbe *p,              /* The virtual machine */
@@ -51707,11 +51667,11 @@
   Mem *pMem = &p->aMem[p->nMem-iCur];
 
   int nByte;
   VdbeCursor *pCx = 0;
   nByte =
-      sizeof(VdbeCursor) +
+      ROUND8(sizeof(VdbeCursor)) +
       (isBtreeCursor?sqlite3BtreeCursorSize():0) +
       2*nField*sizeof(u32);
 
   assert( iCur<p->nCursor );
   if( p->apCsr[iCur] ){
@@ -51718,19 +51678,20 @@
     sqlite3VdbeFreeCursor(p, p->apCsr[iCur]);
     p->apCsr[iCur] = 0;
   }
   if( SQLITE_OK==sqlite3VdbeMemGrow(pMem, nByte, 0) ){
     p->apCsr[iCur] = pCx = (VdbeCursor*)pMem->z;
-    memset(pMem->z, 0, nByte);
+    memset(pCx, 0, sizeof(VdbeCursor));
     pCx->iDb = iDb;
     pCx->nField = nField;
     if( nField ){
-      pCx->aType = (u32 *)&pMem->z[sizeof(VdbeCursor)];
+      pCx->aType = (u32 *)&pMem->z[ROUND8(sizeof(VdbeCursor))];
     }
     if( isBtreeCursor ){
       pCx->pCursor = (BtCursor*)
-          &pMem->z[sizeof(VdbeCursor)+2*nField*sizeof(u32)];
+          &pMem->z[ROUND8(sizeof(VdbeCursor))+2*nField*sizeof(u32)];
+      sqlite3BtreeCursorZero(pCx->pCursor);
     }
   }
   return pCx;
 }
 
@@ -51968,12 +51929,10 @@
 **
 ******************************************************************************
 **
 ** This file contains inline asm code for retrieving "high-performance"
 ** counters for x86 class CPUs.
-**
-** $Id: hwtime.h,v 1.3 2008/08/01 14:33:15 shane Exp $
 */
 #ifndef _HWTIME_H_
 #define _HWTIME_H_
 
 /*
@@ -52132,27 +52091,30 @@
 */
 SQLITE_PRIVATE int sqlite3VdbeExec(
   Vdbe *p                    /* The VDBE */
 ){
   int pc;                    /* The program counter */
+  Op *aOp = p->aOp;          /* Copy of p->aOp */
   Op *pOp;                   /* Current operation */
   int rc = SQLITE_OK;        /* Value to return */
   sqlite3 *db = p->db;       /* The database */
+  u8 resetSchemaOnFault = 0; /* Reset schema after an error if true */
   u8 encoding = ENC(db);     /* The database encoding */
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+  u8 checkProgress;          /* True if progress callbacks are enabled */
+  int nProgressOps = 0;      /* Opcodes executed since progress callback. */
+#endif
+  Mem *aMem = p->aMem;       /* Copy of p->aMem */
   Mem *pIn1 = 0;             /* 1st input operand */
   Mem *pIn2 = 0;             /* 2nd input operand */
   Mem *pIn3 = 0;             /* 3rd input operand */
   Mem *pOut = 0;             /* Output operand */
-  u8 opProperty;
   int iCompare = 0;          /* Result of last OP_Compare operation */
   int *aPermute = 0;         /* Permutation of columns for OP_Compare */
 #ifdef VDBE_PROFILE
   u64 start;                 /* CPU clock count at start of opcode */
   int origPc;                /* Program counter at start of opcode */
-#endif
-#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
-  int nProgressOps = 0;      /* Opcodes executed since progress callback. */
 #endif
   /********************************************************************
   ** Automatically generated code
   **
   ** The following union is automatically generated by the
@@ -52245,14 +52207,12 @@
       int szHdr;         /* Size of the header size field at start of record */
       int avail;         /* Number of bytes of available data */
       Mem *pReg;         /* PseudoTable input register */
     } am;
     struct OP_Affinity_stack_vars {
-      char *zAffinity;   /* The affinity to be applied */
-      Mem *pData0;       /* First register to which to apply affinity */
-      Mem *pLast;        /* Last register to which to apply affinity */
-      Mem *pRec;         /* Current register */
+      const char *zAffinity;   /* The affinity to be applied */
+      char cAff;               /* A single character of affinity */
     } an;
     struct OP_MakeRecord_stack_vars {
       u8 *zNewRecord;        /* A buffer to hold the data for the new record */
       Mem *pRec;             /* The new record */
       u64 nData;             /* Number of bytes of data space */
@@ -52333,18 +52293,19 @@
     struct OP_Found_stack_vars {
       int alreadyExists;
       VdbeCursor *pC;
       int res;
       UnpackedRecord *pIdxKey;
+      UnpackedRecord r;
       char aTempRec[ROUND8(sizeof(UnpackedRecord)) + sizeof(Mem)*3 + 7];
     } bb;
     struct OP_IsUnique_stack_vars {
       u16 ii;
       VdbeCursor *pCx;
       BtCursor *pCrsr;
       u16 nField;
-      Mem *aMem;
+      Mem *aMx;
       UnpackedRecord r;                  /* B-Tree index search key */
       i64 R;                             /* Rowid stored in register P3 */
     } bc;
     struct OP_NotExists_stack_vars {
       VdbeCursor *pC;
@@ -52453,63 +52414,58 @@
       int j;          /* Loop counter */
       int nErr;       /* Number of errors reported */
       char *z;        /* Text of the error report */
       Mem *pnErr;     /* Register keeping track of errors remaining */
     } bv;
-    struct OP_RowSetAdd_stack_vars {
-      Mem *pIdx;
-      Mem *pVal;
-    } bw;
     struct OP_RowSetRead_stack_vars {
-      Mem *pIdx;
       i64 val;
-    } bx;
+    } bw;
     struct OP_RowSetTest_stack_vars {
       int iSet;
       int exists;
-    } by;
+    } bx;
     struct OP_Program_stack_vars {
       int nMem;               /* Number of memory registers for sub-program */
       int nByte;              /* Bytes of runtime space required for sub-program */
       Mem *pRt;               /* Register to allocate runtime space */
       Mem *pMem;              /* Used to iterate through memory cells */
       Mem *pEnd;              /* Last memory cell in new array */
       VdbeFrame *pFrame;      /* New vdbe frame to execute in */
       SubProgram *pProgram;   /* Sub-program to execute */
       void *t;                /* Token identifying trigger */
-    } bz;
+    } by;
     struct OP_Param_stack_vars {
       VdbeFrame *pFrame;
       Mem *pIn;
-    } ca;
+    } bz;
     struct OP_MemMax_stack_vars {
       Mem *pIn1;
       VdbeFrame *pFrame;
-    } cb;
+    } ca;
     struct OP_AggStep_stack_vars {
       int n;
       int i;
       Mem *pMem;
       Mem *pRec;
       sqlite3_context ctx;
       sqlite3_value **apVal;
-    } cc;
+    } cb;
     struct OP_AggFinal_stack_vars {
       Mem *pMem;
-    } cd;
+    } cc;
     struct OP_IncrVacuum_stack_vars {
       Btree *pBt;
-    } ce;
+    } cd;
     struct OP_VBegin_stack_vars {
       VTable *pVTab;
-    } cf;
+    } ce;
     struct OP_VOpen_stack_vars {
       VdbeCursor *pCur;
       sqlite3_vtab_cursor *pVtabCursor;
       sqlite3_vtab *pVtab;
       sqlite3_module *pModule;
-    } cg;
+    } cf;
     struct OP_VFilter_stack_vars {
       int nArg;
       int iQuery;
       const sqlite3_module *pModule;
       Mem *pQuery;
@@ -52518,44 +52474,44 @@
       sqlite3_vtab *pVtab;
       VdbeCursor *pCur;
       int res;
       int i;
       Mem **apArg;
-    } ch;
+    } cg;
     struct OP_VColumn_stack_vars {
       sqlite3_vtab *pVtab;
       const sqlite3_module *pModule;
       Mem *pDest;
       sqlite3_context sContext;
-    } ci;
+    } ch;
     struct OP_VNext_stack_vars {
       sqlite3_vtab *pVtab;
       const sqlite3_module *pModule;
       int res;
       VdbeCursor *pCur;
-    } cj;
+    } ci;
     struct OP_VRename_stack_vars {
       sqlite3_vtab *pVtab;
       Mem *pName;
-    } ck;
+    } cj;
     struct OP_VUpdate_stack_vars {
       sqlite3_vtab *pVtab;
       sqlite3_module *pModule;
       int nArg;
       int i;
       sqlite_int64 rowid;
       Mem **apArg;
       Mem *pX;
-    } cl;
+    } ck;
     struct OP_Pagecount_stack_vars {
       int p1;
       int nPage;
       Pager *pPager;
-    } cm;
+    } cl;
     struct OP_Trace_stack_vars {
       char *zTrace;
-    } cn;
+    } cm;
   } u;
   /* End automatically generated code
   ********************************************************************/
 
   assert( p->magic==VDBE_MAGIC_RUN );  /* sqlite3_step() verifies this */
@@ -52571,20 +52527,23 @@
   assert( p->explain==0 );
   p->pResultSet = 0;
   db->busyHandler.nBusy = 0;
   CHECK_FOR_INTERRUPT;
   sqlite3VdbeIOTraceSql(p);
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+  checkProgress = db->xProgress!=0;
+#endif
 #ifdef SQLITE_DEBUG
   sqlite3BeginBenignMalloc();
   if( p->pc==0
    && ((p->db->flags & SQLITE_VdbeListing) || fileExists(db, "vdbe_explain"))
   ){
     int i;
     printf("VDBE Program Listing:\n");
     sqlite3VdbePrintSql(p);
     for(i=0; i<p->nOp; i++){
-      sqlite3VdbePrintOp(stdout, i, &p->aOp[i]);
+      sqlite3VdbePrintOp(stdout, i, &aOp[i]);
     }
   }
   if( fileExists(db, "vdbe_trace") ){
     p->trace = stdout;
   }
@@ -52595,11 +52554,11 @@
     if( db->mallocFailed ) goto no_mem;
 #ifdef VDBE_PROFILE
     origPc = pc;
     start = sqlite3Hwtime();
 #endif
-    pOp = &p->aOp[pc];
+    pOp = &aOp[pc];
 
     /* Only allow tracing if SQLITE_DEBUG is defined.
     */
 #ifdef SQLITE_DEBUG
     if( p->trace ){
@@ -52636,11 +52595,11 @@
     ** of VDBE ops have been executed (either since this invocation of
     ** sqlite3VdbeExec() or since last time the progress callback was called).
     ** If the progress callback returns non-zero, exit the virtual machine with
     ** a return code SQLITE_ABORT.
     */
-    if( db->xProgress ){
+    if( checkProgress ){
       if( db->nProgressOps==nProgressOps ){
         int prc;
         if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
         prc =db->xProgress(db->pProgressArg);
         if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
@@ -52652,69 +52611,50 @@
       }
       nProgressOps++;
     }
 #endif
 
-    /* Do common setup processing for any opcode that is marked
-    ** with the "out2-prerelease" tag.  Such opcodes have a single
-    ** output which is specified by the P2 parameter.  The P2 register
-    ** is initialized to a NULL.
-    */
-    opProperty = opcodeProperty[pOp->opcode];
-    if( (opProperty & OPFLG_OUT2_PRERELEASE)!=0 ){
+    /* On any opcode with the "out2-prerelase" tag, free any
+    ** external allocations out of mem[p2] and set mem[p2] to be
+    ** an undefined integer.  Opcodes will either fill in the integer
+    ** value or convert mem[p2] to a different type.
+    */
+    assert( pOp->opflags==sqlite3OpcodeProperty[pOp->opcode] );
+    if( pOp->opflags & OPFLG_OUT2_PRERELEASE ){
       assert( pOp->p2>0 );
       assert( pOp->p2<=p->nMem );
-      pOut = &p->aMem[pOp->p2];
+      pOut = &aMem[pOp->p2];
       sqlite3VdbeMemReleaseExternal(pOut);
-      pOut->flags = MEM_Null;
-      pOut->n = 0;
-    }else
-
-    /* Do common setup for opcodes marked with one of the following
-    ** combinations of properties.
-    **
-    **           in1
-    **           in1 in2
-    **           in1 in2 out3
-    **           in1 in3
-    **
-    ** Variables pIn1, pIn2, and pIn3 are made to point to appropriate
-    ** registers for inputs.  Variable pOut points to the output register.
-    */
-    if( (opProperty & OPFLG_IN1)!=0 ){
+      pOut->flags = MEM_Int;
+    }
+
+    /* Sanity checking on other operands */
+#ifdef SQLITE_DEBUG
+    if( (pOp->opflags & OPFLG_IN1)!=0 ){
       assert( pOp->p1>0 );
       assert( pOp->p1<=p->nMem );
-      pIn1 = &p->aMem[pOp->p1];
-      REGISTER_TRACE(pOp->p1, pIn1);
-      if( (opProperty & OPFLG_IN2)!=0 ){
-        assert( pOp->p2>0 );
-        assert( pOp->p2<=p->nMem );
-        pIn2 = &p->aMem[pOp->p2];
-        REGISTER_TRACE(pOp->p2, pIn2);
-        /* As currently implemented, in2 implies out3.  There is no reason
-        ** why this has to be, it just worked out that way. */
-        assert( (opProperty & OPFLG_OUT3)!=0 );
-        assert( pOp->p3>0 );
-        assert( pOp->p3<=p->nMem );
-        pOut = &p->aMem[pOp->p3];
-      }else if( (opProperty & OPFLG_IN3)!=0 ){
-        assert( pOp->p3>0 );
-        assert( pOp->p3<=p->nMem );
-        pIn3 = &p->aMem[pOp->p3];
-        REGISTER_TRACE(pOp->p3, pIn3);
-      }
-    }else if( (opProperty & OPFLG_IN2)!=0 ){
+      REGISTER_TRACE(pOp->p1, &aMem[pOp->p1]);
+    }
+    if( (pOp->opflags & OPFLG_IN2)!=0 ){
+      assert( pOp->p2>0 );
+      assert( pOp->p2<=p->nMem );
+      REGISTER_TRACE(pOp->p2, &aMem[pOp->p2]);
+    }
+    if( (pOp->opflags & OPFLG_IN3)!=0 ){
+      assert( pOp->p3>0 );
+      assert( pOp->p3<=p->nMem );
+      REGISTER_TRACE(pOp->p3, &aMem[pOp->p3]);
+    }
+    if( (pOp->opflags & OPFLG_OUT2)!=0 ){
       assert( pOp->p2>0 );
       assert( pOp->p2<=p->nMem );
-      pIn2 = &p->aMem[pOp->p2];
-      REGISTER_TRACE(pOp->p2, pIn2);
-    }else if( (opProperty & OPFLG_IN3)!=0 ){
+    }
+    if( (pOp->opflags & OPFLG_OUT3)!=0 ){
       assert( pOp->p3>0 );
       assert( pOp->p3<=p->nMem );
-      pIn3 = &p->aMem[pOp->p3];
-      REGISTER_TRACE(pOp->p3, pIn3);
-    }
+    }
+#endif
 
     switch( pOp->opcode ){
 
 /*****************************************************************************
 ** What follows is a massive switch statement where each case implements a
@@ -52767,14 +52707,12 @@
 /* Opcode:  Gosub P1 P2 * * *
 **
 ** Write the current address onto register P1
 ** and then jump to address P2.
 */
-case OP_Gosub: {            /* jump */
-  assert( pOp->p1>0 );
-  assert( pOp->p1<=p->nMem );
-  pIn1 = &p->aMem[pOp->p1];
+case OP_Gosub: {            /* jump, in1 */
+  pIn1 = &aMem[pOp->p1];
   assert( (pIn1->flags & MEM_Dyn)==0 );
   pIn1->flags = MEM_Int;
   pIn1->u.i = pc;
   REGISTER_TRACE(pOp->p1, pIn1);
   pc = pOp->p2 - 1;
@@ -52784,10 +52722,11 @@
 /* Opcode:  Return P1 * * * *
 **
 ** Jump to the next instruction after the address in register P1.
 */
 case OP_Return: {           /* in1 */
+  pIn1 = &aMem[pOp->p1];
   assert( pIn1->flags & MEM_Int );
   pc = (int)pIn1->u.i;
   break;
 }
 
@@ -52797,10 +52736,11 @@
 */
 case OP_Yield: {            /* in1 */
 #if 0  /* local variables moved into u.aa */
   int pcDest;
 #endif /* local variables moved into u.aa */
+  pIn1 = &aMem[pOp->p1];
   assert( (pIn1->flags & MEM_Dyn)==0 );
   pIn1->flags = MEM_Int;
   u.aa.pcDest = (int)pIn1->u.i;
   pIn1->u.i = pc;
   REGISTER_TRACE(pOp->p1, pIn1);
@@ -52813,10 +52753,11 @@
 ** Check the value in register P3.  If is is NULL then Halt using
 ** parameter P1, P2, and P4 as if this were a Halt instruction.  If the
 ** value in register P3 is not NULL, then this routine is a no-op.
 */
 case OP_HaltIfNull: {      /* in3 */
+  pIn3 = &aMem[pOp->p3];
   if( (pIn3->flags & MEM_Null)==0 ) break;
   /* Fall through into OP_Halt */
 }
 
 /* Opcode:  Halt P1 P2 * P4 *
@@ -52852,10 +52793,12 @@
       ** instruction is set to OE_Ignore, then the sub-program is throwing
       ** an IGNORE exception. In this case jump to the address specified
       ** as the p2 of the calling OP_Program.  */
       pc = p->aOp[pc].p2-1;
     }
+    aOp = p->aOp;
+    aMem = p->aMem;
     break;
   }
 
   p->rc = pOp->p1;
   p->errorAction = (u8)pOp->p2;
@@ -52878,11 +52821,10 @@
 /* Opcode: Integer P1 P2 * * *
 **
 ** The 32-bit integer value P1 is written into register P2.
 */
 case OP_Integer: {         /* out2-prerelease */
-  pOut->flags = MEM_Int;
   pOut->u.i = pOp->p1;
   break;
 }
 
 /* Opcode: Int64 * P2 * P4 *
@@ -52890,11 +52832,10 @@
 ** P4 is a pointer to a 64-bit integer value.
 ** Write that value into register P2.
 */
 case OP_Int64: {           /* out2-prerelease */
   assert( pOp->p4.pI64!=0 );
-  pOut->flags = MEM_Int;
   pOut->u.i = *pOp->p4.pI64;
   break;
 }
 
 /* Opcode: Real * P2 * P4 *
@@ -52960,10 +52901,11 @@
 /* Opcode: Null * P2 * * *
 **
 ** Write a NULL into register P2.
 */
 case OP_Null: {           /* out2-prerelease */
+  pOut->flags = MEM_Null;
   break;
 }
 
 
 /* Opcode: Blob P1 P2 * P4
@@ -53009,11 +52951,11 @@
   while( u.ab.n-- > 0 ){
     u.ab.pVar = &p->aVar[u.ab.p1++];
     if( sqlite3VdbeMemTooBig(u.ab.pVar) ){
       goto too_big;
     }
-    pOut = &p->aMem[u.ab.p2++];
+    pOut = &aMem[u.ab.p2++];
     sqlite3VdbeMemReleaseExternal(pOut);
     pOut->flags = MEM_Null;
     sqlite3VdbeMemShallowCopy(pOut, u.ab.pVar, MEM_Static);
     UPDATE_MAX_BLOBSIZE(pOut);
   }
@@ -53039,15 +52981,15 @@
   u.ac.p1 = pOp->p1;
   u.ac.p2 = pOp->p2;
   assert( u.ac.n>0 && u.ac.p1>0 && u.ac.p2>0 );
   assert( u.ac.p1+u.ac.n<=u.ac.p2 || u.ac.p2+u.ac.n<=u.ac.p1 );
 
-  pIn1 = &p->aMem[u.ac.p1];
-  pOut = &p->aMem[u.ac.p2];
+  pIn1 = &aMem[u.ac.p1];
+  pOut = &aMem[u.ac.p2];
   while( u.ac.n-- ){
-    assert( pOut<=&p->aMem[p->nMem] );
-    assert( pIn1<=&p->aMem[p->nMem] );
+    assert( pOut<=&aMem[p->nMem] );
+    assert( pIn1<=&aMem[p->nMem] );
     u.ac.zMalloc = pOut->zMalloc;
     pOut->zMalloc = 0;
     sqlite3VdbeMemMove(pOut, pIn1);
     pIn1->zMalloc = u.ac.zMalloc;
     REGISTER_TRACE(u.ac.p2++, pOut);
@@ -53062,14 +53004,13 @@
 ** Make a copy of register P1 into register P2.
 **
 ** This instruction makes a deep copy of the value.  A duplicate
 ** is made of any string or blob constant.  See also OP_SCopy.
 */
-case OP_Copy: {             /* in1 */
-  assert( pOp->p2>0 );
-  assert( pOp->p2<=p->nMem );
-  pOut = &p->aMem[pOp->p2];
+case OP_Copy: {             /* in1, out2 */
+  pIn1 = &aMem[pOp->p1];
+  pOut = &aMem[pOp->p2];
   assert( pOut!=pIn1 );
   sqlite3VdbeMemShallowCopy(pOut, pIn1, MEM_Ephem);
   Deephemeralize(pOut);
   REGISTER_TRACE(pOp->p2, pOut);
   break;
@@ -53085,15 +53026,13 @@
 ** Worse, if the original is deallocated, the copy becomes invalid.
 ** Thus the program must guarantee that the original will not change
 ** during the lifetime of the copy.  Use OP_Copy to make a complete
 ** copy.
 */
-case OP_SCopy: {            /* in1 */
-  REGISTER_TRACE(pOp->p1, pIn1);
-  assert( pOp->p2>0 );
-  assert( pOp->p2<=p->nMem );
-  pOut = &p->aMem[pOp->p2];
+case OP_SCopy: {            /* in1, out2 */
+  pIn1 = &aMem[pOp->p1];
+  pOut = &aMem[pOp->p2];
   assert( pOut!=pIn1 );
   sqlite3VdbeMemShallowCopy(pOut, pIn1, MEM_Ephem);
   REGISTER_TRACE(pOp->p2, pOut);
   break;
 }
@@ -53150,11 +53089,11 @@
 
   /* Make sure the results of the current row are \000 terminated
   ** and have an assigned type.  The results are de-ephemeralized as
   ** as side effect.
   */
-  u.ad.pMem = p->pResultSet = &p->aMem[pOp->p1];
+  u.ad.pMem = p->pResultSet = &aMem[pOp->p1];
   for(u.ad.i=0; u.ad.i<pOp->p2; u.ad.i++){
     sqlite3VdbeMemNulTerminate(&u.ad.pMem[u.ad.i]);
     sqlite3VdbeMemStoreType(&u.ad.pMem[u.ad.i]);
     REGISTER_TRACE(pOp->p1+u.ad.i, &u.ad.pMem[u.ad.i]);
   }
@@ -53182,10 +53121,13 @@
 case OP_Concat: {           /* same as TK_CONCAT, in1, in2, out3 */
 #if 0  /* local variables moved into u.ae */
   i64 nByte;
 #endif /* local variables moved into u.ae */
 
+  pIn1 = &aMem[pOp->p1];
+  pIn2 = &aMem[pOp->p2];
+  pOut = &aMem[pOp->p3];
   assert( pIn1!=pOut );
   if( (pIn1->flags | pIn2->flags) & MEM_Null ){
     sqlite3VdbeMemSetNull(pOut);
     break;
   }
@@ -53257,12 +53199,15 @@
   i64 iB;         /* Integer value of right operand */
   double rA;      /* Real value of left operand */
   double rB;      /* Real value of right operand */
 #endif /* local variables moved into u.af */
 
+  pIn1 = &aMem[pOp->p1];
   applyNumericAffinity(pIn1);
+  pIn2 = &aMem[pOp->p2];
   applyNumericAffinity(pIn2);
+  pOut = &aMem[pOp->p3];
   u.af.flags = pIn1->flags | pIn2->flags;
   if( (u.af.flags & MEM_Null)!=0 ) goto arithmetic_result_is_null;
   if( (pIn1->flags & pIn2->flags & MEM_Int)==MEM_Int ){
     u.af.iA = pIn1->u.i;
     u.af.iB = pIn2->u.i;
@@ -53375,11 +53320,11 @@
   u.ag.apVal = p->apArg;
   assert( u.ag.apVal || u.ag.n==0 );
 
   assert( u.ag.n==0 || (pOp->p2>0 && pOp->p2+u.ag.n<=p->nMem+1) );
   assert( pOp->p3<pOp->p2 || pOp->p3>=pOp->p2+u.ag.n );
-  u.ag.pArg = &p->aMem[pOp->p2];
+  u.ag.pArg = &aMem[pOp->p2];
   for(u.ag.i=0; u.ag.i<u.ag.n; u.ag.i++, u.ag.pArg++){
     u.ag.apVal[u.ag.i] = u.ag.pArg;
     sqlite3VdbeMemStoreType(u.ag.pArg);
     REGISTER_TRACE(pOp->p2, u.ag.pArg);
   }
@@ -53392,11 +53337,11 @@
     u.ag.ctx.pVdbeFunc = (VdbeFunc*)pOp->p4.pVdbeFunc;
     u.ag.ctx.pFunc = u.ag.ctx.pVdbeFunc->pFunc;
   }
 
   assert( pOp->p3>0 && pOp->p3<=p->nMem );
-  pOut = &p->aMem[pOp->p3];
+  pOut = &aMem[pOp->p3];
   u.ag.ctx.s.flags = MEM_Null;
   u.ag.ctx.s.db = db;
   u.ag.ctx.s.xDel = 0;
   u.ag.ctx.s.zMalloc = 0;
 
@@ -53407,11 +53352,11 @@
   sqlite3VdbeMemMove(&u.ag.ctx.s, pOut);
   MemSetTypeFlag(&u.ag.ctx.s, MEM_Null);
 
   u.ag.ctx.isError = 0;
   if( u.ag.ctx.pFunc->flags & SQLITE_FUNC_NEEDCOLL ){
-    assert( pOp>p->aOp );
+    assert( pOp>aOp );
     assert( pOp[-1].p4type==P4_COLLSEQ );
     assert( pOp[-1].opcode==OP_CollSeq );
     u.ag.ctx.pColl = pOp[-1].p4.pColl;
   }
   if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
@@ -53493,10 +53438,13 @@
 #if 0  /* local variables moved into u.ah */
   i64 a;
   i64 b;
 #endif /* local variables moved into u.ah */
 
+  pIn1 = &aMem[pOp->p1];
+  pIn2 = &aMem[pOp->p2];
+  pOut = &aMem[pOp->p3];
   if( (pIn1->flags | pIn2->flags) & MEM_Null ){
     sqlite3VdbeMemSetNull(pOut);
     break;
   }
   u.ah.a = sqlite3VdbeIntValue(pIn2);
@@ -53519,10 +53467,11 @@
 ** The result is always an integer.
 **
 ** To force any register to be an integer, just add 0.
 */
 case OP_AddImm: {            /* in1 */
+  pIn1 = &aMem[pOp->p1];
   sqlite3VdbeMemIntegerify(pIn1);
   pIn1->u.i += pOp->p2;
   break;
 }
 
@@ -53532,10 +53481,11 @@
 ** in P1 is not an integer and cannot be converted into an integer
 ** without data loss, then jump immediately to P2, or if P2==0
 ** raise an SQLITE_MISMATCH exception.
 */
 case OP_MustBeInt: {            /* jump, in1 */
+  pIn1 = &aMem[pOp->p1];
   applyAffinity(pIn1, SQLITE_AFF_NUMERIC, encoding);
   if( (pIn1->flags & MEM_Int)==0 ){
     if( pOp->p2==0 ){
       rc = SQLITE_MISMATCH;
       goto abort_due_to_error;
@@ -53556,10 +53506,11 @@
 ** has REAL affinity.  Such column values may still be stored as
 ** integers, for space efficiency, but after extraction we want them
 ** to have only a real value.
 */
 case OP_RealAffinity: {                  /* in1 */
+  pIn1 = &aMem[pOp->p1];
   if( pIn1->flags & MEM_Int ){
     sqlite3VdbeMemRealify(pIn1);
   }
   break;
 }
@@ -53573,10 +53524,11 @@
 ** are afterwards simply interpreted as text.
 **
 ** A NULL value is not changed by this routine.  It remains NULL.
 */
 case OP_ToText: {                  /* same as TK_TO_TEXT, in1 */
+  pIn1 = &aMem[pOp->p1];
   if( pIn1->flags & MEM_Null ) break;
   assert( MEM_Str==(MEM_Blob>>3) );
   pIn1->flags |= (pIn1->flags&MEM_Blob)>>3;
   applyAffinity(pIn1, SQLITE_AFF_TEXT, encoding);
   rc = ExpandBlob(pIn1);
@@ -53594,10 +53546,11 @@
 ** to the underlying data.
 **
 ** A NULL value is not changed by this routine.  It remains NULL.
 */
 case OP_ToBlob: {                  /* same as TK_TO_BLOB, in1 */
+  pIn1 = &aMem[pOp->p1];
   if( pIn1->flags & MEM_Null ) break;
   if( (pIn1->flags & MEM_Blob)==0 ){
     applyAffinity(pIn1, SQLITE_AFF_TEXT, encoding);
     assert( pIn1->flags & MEM_Str || db->mallocFailed );
     MemSetTypeFlag(pIn1, MEM_Blob);
@@ -53617,10 +53570,11 @@
 ** is possible.
 **
 ** A NULL value is not changed by this routine.  It remains NULL.
 */
 case OP_ToNumeric: {                  /* same as TK_TO_NUMERIC, in1 */
+  pIn1 = &aMem[pOp->p1];
   if( (pIn1->flags & (MEM_Null|MEM_Int|MEM_Real))==0 ){
     sqlite3VdbeMemNumerify(pIn1);
   }
   break;
 }
@@ -53634,10 +53588,11 @@
 ** equivalent of atoi() and store 0 if no such conversion is possible.
 **
 ** A NULL value is not changed by this routine.  It remains NULL.
 */
 case OP_ToInt: {                  /* same as TK_TO_INT, in1 */
+  pIn1 = &aMem[pOp->p1];
   if( (pIn1->flags & MEM_Null)==0 ){
     sqlite3VdbeMemIntegerify(pIn1);
   }
   break;
 }
@@ -53651,10 +53606,11 @@
 ** equivalent of atoi() and store 0.0 if no such conversion is possible.
 **
 ** A NULL value is not changed by this routine.  It remains NULL.
 */
 case OP_ToReal: {                  /* same as TK_TO_REAL, in1 */
+  pIn1 = &aMem[pOp->p1];
   if( (pIn1->flags & MEM_Null)==0 ){
     sqlite3VdbeMemRealify(pIn1);
   }
   break;
 }
@@ -53741,10 +53697,12 @@
 #if 0  /* local variables moved into u.ai */
   int res;            /* Result of the comparison of pIn1 against pIn3 */
   char affinity;      /* Affinity to use for comparison */
 #endif /* local variables moved into u.ai */
 
+  pIn1 = &aMem[pOp->p1];
+  pIn3 = &aMem[pOp->p3];
   if( (pIn1->flags | pIn3->flags)&MEM_Null ){
     /* One or both operands are NULL */
     if( pOp->p5 & SQLITE_NULLEQ ){
       /* If SQLITE_NULLEQ is set (which will only happen if the operator is
       ** OP_Eq or OP_Ne) then take the jump or not depending on whether
@@ -53756,11 +53714,11 @@
       /* SQLITE_NULLEQ is clear and at least one operand is NULL,
       ** then the result is always NULL.
       ** The jump is taken if the SQLITE_JUMPIFNULL bit is set.
       */
       if( pOp->p5 & SQLITE_STOREP2 ){
-        pOut = &p->aMem[pOp->p2];
+        pOut = &aMem[pOp->p2];
         MemSetTypeFlag(pOut, MEM_Null);
         REGISTER_TRACE(pOp->p2, pOut);
       }else if( pOp->p5 & SQLITE_JUMPIFNULL ){
         pc = pOp->p2-1;
       }
@@ -53788,11 +53746,11 @@
     case OP_Gt:    u.ai.res = u.ai.res>0;      break;
     default:       u.ai.res = u.ai.res>=0;     break;
   }
 
   if( pOp->p5 & SQLITE_STOREP2 ){
-    pOut = &p->aMem[pOp->p2];
+    pOut = &aMem[pOp->p2];
     MemSetTypeFlag(pOut, MEM_Int);
     pOut->u.i = u.ai.res;
     REGISTER_TRACE(pOp->p2, pOut);
   }else if( u.ai.res ){
     pc = pOp->p2-1;
@@ -53859,16 +53817,16 @@
     assert( u.aj.p2>0 && u.aj.p2+u.aj.n<=p->nMem+1 );
   }
 #endif /* SQLITE_DEBUG */
   for(u.aj.i=0; u.aj.i<u.aj.n; u.aj.i++){
     u.aj.idx = aPermute ? aPermute[u.aj.i] : u.aj.i;
-    REGISTER_TRACE(u.aj.p1+u.aj.idx, &p->aMem[u.aj.p1+u.aj.idx]);
-    REGISTER_TRACE(u.aj.p2+u.aj.idx, &p->aMem[u.aj.p2+u.aj.idx]);
+    REGISTER_TRACE(u.aj.p1+u.aj.idx, &aMem[u.aj.p1+u.aj.idx]);
+    REGISTER_TRACE(u.aj.p2+u.aj.idx, &aMem[u.aj.p2+u.aj.idx]);
     assert( u.aj.i<u.aj.pKeyInfo->nField );
     u.aj.pColl = u.aj.pKeyInfo->aColl[u.aj.i];
     u.aj.bRev = u.aj.pKeyInfo->aSortOrder[u.aj.i];
-    iCompare = sqlite3MemCompare(&p->aMem[u.aj.p1+u.aj.idx], &p->aMem[u.aj.p2+u.aj.idx], u.aj.pColl);
+    iCompare = sqlite3MemCompare(&aMem[u.aj.p1+u.aj.idx], &aMem[u.aj.p2+u.aj.idx], u.aj.pColl);
     if( iCompare ){
       if( u.aj.bRev ) iCompare = -iCompare;
       break;
     }
   }
@@ -53916,15 +53874,17 @@
 #if 0  /* local variables moved into u.ak */
   int v1;    /* Left operand:  0==FALSE, 1==TRUE, 2==UNKNOWN or NULL */
   int v2;    /* Right operand: 0==FALSE, 1==TRUE, 2==UNKNOWN or NULL */
 #endif /* local variables moved into u.ak */
 
+  pIn1 = &aMem[pOp->p1];
   if( pIn1->flags & MEM_Null ){
     u.ak.v1 = 2;
   }else{
     u.ak.v1 = sqlite3VdbeIntValue(pIn1)!=0;
   }
+  pIn2 = &aMem[pOp->p2];
   if( pIn2->flags & MEM_Null ){
     u.ak.v2 = 2;
   }else{
     u.ak.v2 = sqlite3VdbeIntValue(pIn2)!=0;
   }
@@ -53933,10 +53893,11 @@
     u.ak.v1 = and_logic[u.ak.v1*3+u.ak.v2];
   }else{
     static const unsigned char or_logic[] = { 0, 1, 2, 1, 1, 1, 2, 1, 2 };
     u.ak.v1 = or_logic[u.ak.v1*3+u.ak.v2];
   }
+  pOut = &aMem[pOp->p3];
   if( u.ak.v1==2 ){
     MemSetTypeFlag(pOut, MEM_Null);
   }else{
     pOut->u.i = u.ak.v1;
     MemSetTypeFlag(pOut, MEM_Int);
@@ -53948,12 +53909,13 @@
 **
 ** Interpret the value in register P1 as a boolean value.  Store the
 ** boolean complement in register P2.  If the value in register P1 is
 ** NULL, then a NULL is stored in P2.
 */
-case OP_Not: {                /* same as TK_NOT, in1 */
-  pOut = &p->aMem[pOp->p2];
+case OP_Not: {                /* same as TK_NOT, in1, out2 */
+  pIn1 = &aMem[pOp->p1];
+  pOut = &aMem[pOp->p2];
   if( pIn1->flags & MEM_Null ){
     sqlite3VdbeMemSetNull(pOut);
   }else{
     sqlite3VdbeMemSetInt64(pOut, !sqlite3VdbeIntValue(pIn1));
   }
@@ -53964,12 +53926,13 @@
 **
 ** Interpret the content of register P1 as an integer.  Store the
 ** ones-complement of the P1 value into register P2.  If P1 holds
 ** a NULL then store a NULL in P2.
 */
-case OP_BitNot: {             /* same as TK_BITNOT, in1 */
-  pOut = &p->aMem[pOp->p2];
+case OP_BitNot: {             /* same as TK_BITNOT, in1, out2 */
+  pIn1 = &aMem[pOp->p1];
+  pOut = &aMem[pOp->p2];
   if( pIn1->flags & MEM_Null ){
     sqlite3VdbeMemSetNull(pOut);
   }else{
     sqlite3VdbeMemSetInt64(pOut, ~sqlite3VdbeIntValue(pIn1));
   }
@@ -53991,10 +53954,11 @@
 case OP_If:                 /* jump, in1 */
 case OP_IfNot: {            /* jump, in1 */
 #if 0  /* local variables moved into u.al */
   int c;
 #endif /* local variables moved into u.al */
+  pIn1 = &aMem[pOp->p1];
   if( pIn1->flags & MEM_Null ){
     u.al.c = pOp->p3;
   }else{
 #ifdef SQLITE_OMIT_FLOATING_POINT
     u.al.c = sqlite3VdbeIntValue(pIn1)!=0;
@@ -54012,10 +53976,11 @@
 /* Opcode: IsNull P1 P2 * * *
 **
 ** Jump to P2 if the value in register P1 is NULL.
 */
 case OP_IsNull: {            /* same as TK_ISNULL, jump, in1 */
+  pIn1 = &aMem[pOp->p1];
   if( (pIn1->flags & MEM_Null)!=0 ){
     pc = pOp->p2 - 1;
   }
   break;
 }
@@ -54023,10 +53988,11 @@
 /* Opcode: NotNull P1 P2 * * *
 **
 ** Jump to P2 if the value in register P1 is not NULL.
 */
 case OP_NotNull: {            /* same as TK_NOTNULL, jump, in1 */
+  pIn1 = &aMem[pOp->p1];
   if( (pIn1->flags & MEM_Null)==0 ){
     pc = pOp->p2 - 1;
   }
   break;
 }
@@ -54081,11 +54047,11 @@
   u.am.p2 = pOp->p2;
   u.am.pC = 0;
   memset(&u.am.sMem, 0, sizeof(u.am.sMem));
   assert( u.am.p1<p->nCursor );
   assert( pOp->p3>0 && pOp->p3<=p->nMem );
-  u.am.pDest = &p->aMem[pOp->p3];
+  u.am.pDest = &aMem[pOp->p3];
   MemSetTypeFlag(u.am.pDest, MEM_Null);
   u.am.zRec = 0;
 
   /* This block sets the variable u.am.payloadSize to be the total number of
   ** bytes in the record.
@@ -54127,11 +54093,11 @@
       assert( sqlite3BtreeCursorIsValid(u.am.pCrsr) );
       rc = sqlite3BtreeDataSize(u.am.pCrsr, &u.am.payloadSize);
       assert( rc==SQLITE_OK );   /* DataSize() cannot fail */
     }
   }else if( u.am.pC->pseudoTableReg>0 ){
-    u.am.pReg = &p->aMem[u.am.pC->pseudoTableReg];
+    u.am.pReg = &aMem[u.am.pC->pseudoTableReg];
     assert( u.am.pReg->flags & MEM_Blob );
     u.am.payloadSize = u.am.pReg->n;
     u.am.zRec = u.am.pReg->z;
     u.am.pC->cacheStatus = (pOp->p5&OPFLAG_CLEARCACHE) ? CACHE_STALE : p->cacheCtr;
     assert( u.am.payloadSize==0 || u.am.zRec!=0 );
@@ -54339,22 +54305,23 @@
 ** string indicates the column affinity that should be used for the nth
 ** memory cell in the range.
 */
 case OP_Affinity: {
 #if 0  /* local variables moved into u.an */
-  char *zAffinity;   /* The affinity to be applied */
-  Mem *pData0;       /* First register to which to apply affinity */
-  Mem *pLast;        /* Last register to which to apply affinity */
-  Mem *pRec;         /* Current register */
+  const char *zAffinity;   /* The affinity to be applied */
+  char cAff;               /* A single character of affinity */
 #endif /* local variables moved into u.an */
 
   u.an.zAffinity = pOp->p4.z;
-  u.an.pData0 = &p->aMem[pOp->p1];
-  u.an.pLast = &u.an.pData0[pOp->p2-1];
-  for(u.an.pRec=u.an.pData0; u.an.pRec<=u.an.pLast; u.an.pRec++){
-    ExpandBlob(u.an.pRec);
-    applyAffinity(u.an.pRec, u.an.zAffinity[u.an.pRec-u.an.pData0], encoding);
+  assert( u.an.zAffinity!=0 );
+  assert( u.an.zAffinity[pOp->p2]==0 );
+  pIn1 = &aMem[pOp->p1];
+  while( (u.an.cAff = *(u.an.zAffinity++))!=0 ){
+    assert( pIn1 <= &p->aMem[p->nMem] );
+    ExpandBlob(pIn1);
+    applyAffinity(pIn1, u.an.cAff, encoding);
+    pIn1++;
   }
   break;
 }
 
 /* Opcode: MakeRecord P1 P2 P3 P4 *
@@ -54414,11 +54381,11 @@
   u.ao.nByte = 0;         /* Data space required for this record */
   u.ao.nZero = 0;         /* Number of zero bytes at the end of the record */
   u.ao.nField = pOp->p1;
   u.ao.zAffinity = pOp->p4.z;
   assert( u.ao.nField>0 && pOp->p2>0 && pOp->p2+u.ao.nField<=p->nMem+1 );
-  u.ao.pData0 = &p->aMem[u.ao.nField];
+  u.ao.pData0 = &aMem[u.ao.nField];
   u.ao.nField = pOp->p2;
   u.ao.pLast = &u.ao.pData0[u.ao.nField-1];
   u.ao.file_format = p->minWriteFileFormat;
 
   /* Loop through the elements that will make up the record to figure
@@ -54458,11 +54425,11 @@
   ** the new record. The output register (pOp->p3) is not allowed to
   ** be one of the input registers (because the following call to
   ** sqlite3VdbeMemGrow() could clobber the value before it is used).
   */
   assert( pOp->p3<pOp->p1 || pOp->p3>=pOp->p1+pOp->p2 );
-  pOut = &p->aMem[pOp->p3];
+  pOut = &aMem[pOp->p3];
   if( sqlite3VdbeMemGrow(pOut, (int)u.ao.nByte, 0) ){
     goto no_mem;
   }
   u.ao.zNewRecord = (u8 *)pOut->z;
 
@@ -54507,11 +54474,10 @@
   if( u.ap.pCrsr ){
     rc = sqlite3BtreeCount(u.ap.pCrsr, &u.ap.nEntry);
   }else{
     u.ap.nEntry = 0;
   }
-  pOut->flags = MEM_Int;
   pOut->u.i = u.ap.nEntry;
   break;
 }
 #endif
 
@@ -54836,11 +54802,10 @@
   assert( db->aDb[u.at.iDb].pBt!=0 );
   assert( (p->btreeMask & (1<<u.at.iDb))!=0 );
 
   sqlite3BtreeGetMeta(db->aDb[u.at.iDb].pBt, u.at.iCookie, (u32 *)&u.at.iMeta);
   pOut->u.i = u.at.iMeta;
-  MemSetTypeFlag(pOut, MEM_Int);
   break;
 }
 
 /* Opcode: SetCookie P1 P2 P3 * *
 **
@@ -54859,10 +54824,11 @@
   assert( pOp->p2<SQLITE_N_BTREE_META );
   assert( pOp->p1>=0 && pOp->p1<db->nDb );
   assert( (p->btreeMask & (1<<pOp->p1))!=0 );
   u.au.pDb = &db->aDb[pOp->p1];
   assert( u.au.pDb->pBt!=0 );
+  pIn3 = &aMem[pOp->p3];
   sqlite3VdbeMemIntegerify(pIn3);
   /* See note about index shifting on OP_ReadCookie */
   rc = sqlite3BtreeUpdateMeta(u.au.pDb->pBt, pOp->p2, (int)pIn3->u.i);
   if( pOp->p2==BTREE_SCHEMA_VERSION ){
     /* When the schema cookie changes, record the new cookie internally */
@@ -55021,11 +54987,11 @@
     u.aw.wrFlag = 0;
   }
   if( pOp->p5 ){
     assert( u.aw.p2>0 );
     assert( u.aw.p2<=p->nMem );
-    pIn2 = &p->aMem[u.aw.p2];
+    pIn2 = &aMem[u.aw.p2];
     sqlite3VdbeMemIntegerify(pIn2);
     u.aw.p2 = (int)pIn2->u.i;
     /* The u.aw.p2 value always comes from a prior OP_CreateTable opcode and
     ** that opcode will always set the u.aw.p2 value to 2 or more or else fail.
     ** If there were a failure, the prepared statement would have halted
@@ -55243,17 +55209,21 @@
   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
   assert( pOp->p2!=0 );
   u.az.pC = p->apCsr[pOp->p1];
   assert( u.az.pC!=0 );
   assert( u.az.pC->pseudoTableReg==0 );
+  assert( OP_SeekLe == OP_SeekLt+1 );
+  assert( OP_SeekGe == OP_SeekLt+2 );
+  assert( OP_SeekGt == OP_SeekLt+3 );
   if( u.az.pC->pCursor!=0 ){
     u.az.oc = pOp->opcode;
     u.az.pC->nullRow = 0;
     if( u.az.pC->isTable ){
       /* The input value in P3 might be of any type: integer, real, string,
       ** blob, or NULL.  But it needs to be an integer before we can do
       ** the seek, so covert it. */
+      pIn3 = &aMem[pOp->p3];
       applyNumericAffinity(pIn3);
       u.az.iKey = sqlite3VdbeIntValue(pIn3);
       u.az.pC->rowidIsValid = 0;
 
       /* If the P3 value could not be converted into an integer without
@@ -55272,16 +55242,16 @@
         if( u.az.iKey==SMALLEST_INT64 && (pIn3->r<(double)u.az.iKey || pIn3->r>0) ){
           /* The P3 value is too large in magnitude to be expressed as an
           ** integer. */
           u.az.res = 1;
           if( pIn3->r<0 ){
-            if( u.az.oc==OP_SeekGt || u.az.oc==OP_SeekGe ){
+            if( u.az.oc>=OP_SeekGe ){  assert( u.az.oc==OP_SeekGe || u.az.oc==OP_SeekGt );
               rc = sqlite3BtreeFirst(u.az.pC->pCursor, &u.az.res);
               if( rc!=SQLITE_OK ) goto abort_due_to_error;
             }
           }else{
-            if( u.az.oc==OP_SeekLt || u.az.oc==OP_SeekLe ){
+            if( u.az.oc<=OP_SeekLe ){  assert( u.az.oc==OP_SeekLt || u.az.oc==OP_SeekLe );
               rc = sqlite3BtreeLast(u.az.pC->pCursor, &u.az.res);
               if( rc!=SQLITE_OK ) goto abort_due_to_error;
             }
           }
           if( u.az.res ){
@@ -55309,16 +55279,26 @@
       u.az.nField = pOp->p4.i;
       assert( pOp->p4type==P4_INT32 );
       assert( u.az.nField>0 );
       u.az.r.pKeyInfo = u.az.pC->pKeyInfo;
       u.az.r.nField = (u16)u.az.nField;
-      if( u.az.oc==OP_SeekGt || u.az.oc==OP_SeekLe ){
-        u.az.r.flags = UNPACKED_INCRKEY;
-      }else{
-        u.az.r.flags = 0;
-      }
-      u.az.r.aMem = &p->aMem[pOp->p3];
+
+      /* The next line of code computes as follows, only faster:
+      **   if( u.az.oc==OP_SeekGt || u.az.oc==OP_SeekLe ){
+      **     u.az.r.flags = UNPACKED_INCRKEY;
+      **   }else{
+      **     u.az.r.flags = 0;
+      **   }
+      */
+      u.az.r.flags = UNPACKED_INCRKEY * (1 & (u.az.oc - OP_SeekLt));
+      assert( u.az.oc!=OP_SeekGt || u.az.r.flags==UNPACKED_INCRKEY );
+      assert( u.az.oc!=OP_SeekLe || u.az.r.flags==UNPACKED_INCRKEY );
+      assert( u.az.oc!=OP_SeekGe || u.az.r.flags==0 );
+      assert( u.az.oc!=OP_SeekLt || u.az.r.flags==0 );
+
+      u.az.r.aMem = &aMem[pOp->p3];
+      ExpandBlob(u.az.r.aMem);
       rc = sqlite3BtreeMovetoUnpacked(u.az.pC->pCursor, &u.az.r, 0, 0, &u.az.res);
       if( rc!=SQLITE_OK ){
         goto abort_due_to_error;
       }
       u.az.pC->rowidIsValid = 0;
@@ -55326,11 +55306,11 @@
     u.az.pC->deferredMoveto = 0;
     u.az.pC->cacheStatus = CACHE_STALE;
 #ifdef SQLITE_TEST
     sqlite3_search_count++;
 #endif
-    if( u.az.oc==OP_SeekGe || u.az.oc==OP_SeekGt ){
+    if( u.az.oc>=OP_SeekGe ){  assert( u.az.oc==OP_SeekGe || u.az.oc==OP_SeekGt );
       if( u.az.res<0 || (u.az.res==0 && u.az.oc==OP_SeekGt) ){
         rc = sqlite3BtreeNext(u.az.pC->pCursor, &u.az.res);
         if( rc!=SQLITE_OK ) goto abort_due_to_error;
         u.az.pC->rowidIsValid = 0;
       }else{
@@ -55381,45 +55361,40 @@
   u.ba.pC = p->apCsr[pOp->p1];
   assert( u.ba.pC!=0 );
   if( ALWAYS(u.ba.pC->pCursor!=0) ){
     assert( u.ba.pC->isTable );
     u.ba.pC->nullRow = 0;
+    pIn2 = &aMem[pOp->p2];
     u.ba.pC->movetoTarget = sqlite3VdbeIntValue(pIn2);
     u.ba.pC->rowidIsValid = 0;
     u.ba.pC->deferredMoveto = 1;
   }
   break;
 }
 
 
-/* Opcode: Found P1 P2 P3 * *
-**
-** Register P3 holds a blob constructed by MakeRecord.  P1 is an index.
-** If an entry that matches the value in register p3 exists in P1 then
-** jump to P2.  If the P3 value does not match any entry in P1
-** then fall thru.  The P1 cursor is left pointing at the matching entry
-** if it exists.
-**
-** This instruction is used to implement the IN operator where the
-** left-hand side is a SELECT statement.  P1 may be a true index, or it
-** may be a temporary index that holds the results of the SELECT
-** statement.   This instruction is also used to implement the
-** DISTINCT keyword in SELECT statements.
-**
-** This instruction checks if index P1 contains a record for which
-** the first N serialized values exactly match the N serialized values
-** in the record in register P3, where N is the total number of values in
-** the P3 record (the P3 record is a prefix of the P1 record).
-**
-** See also: NotFound, IsUnique, NotExists
-*/
-/* Opcode: NotFound P1 P2 P3 * *
-**
-** Register P3 holds a blob constructed by MakeRecord.  P1 is
-** an index.  If no entry exists in P1 that matches the blob then jump
-** to P2.  If an entry does existing, fall through.  The cursor is left
-** pointing to the entry that matches.
+/* Opcode: Found P1 P2 P3 P4 *
+**
+** If P4==0 then register P3 holds a blob constructed by MakeRecord.  If
+** P4>0 then register P3 is the first of P4 registers that form an unpacked
+** record.
+**
+** Cursor P1 is on an index btree.  If the record identified by P3 and P4
+** is a prefix of any entry in P1 then a jump is made to P2 and
+** P1 is left pointing at the matching entry.
+*/
+/* Opcode: NotFound P1 P2 P3 P4 *
+**
+** If P4==0 then register P3 holds a blob constructed by MakeRecord.  If
+** P4>0 then register P3 is the first of P4 registers that form an unpacked
+** record.
+**
+** Cursor P1 is on an index btree.  If the record identified by P3 and P4
+** is not the prefix of any entry in P1 then a jump is made to P2.  If P1
+** does contain an entry whose prefix matches the P3/P4 record then control
+** falls through to the next instruction and P1 is left pointing at the
+** matching entry.
 **
 ** See also: Found, NotExists, IsUnique
 */
 case OP_NotFound:       /* jump, in3 */
 case OP_Found: {        /* jump, in3 */
@@ -55426,36 +55401,47 @@
 #if 0  /* local variables moved into u.bb */
   int alreadyExists;
   VdbeCursor *pC;
   int res;
   UnpackedRecord *pIdxKey;
+  UnpackedRecord r;
   char aTempRec[ROUND8(sizeof(UnpackedRecord)) + sizeof(Mem)*3 + 7];
 #endif /* local variables moved into u.bb */
 
 #ifdef SQLITE_TEST
   sqlite3_found_count++;
 #endif
 
   u.bb.alreadyExists = 0;
   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  assert( pOp->p4type==P4_INT32 );
   u.bb.pC = p->apCsr[pOp->p1];
   assert( u.bb.pC!=0 );
+  pIn3 = &aMem[pOp->p3];
   if( ALWAYS(u.bb.pC->pCursor!=0) ){
 
     assert( u.bb.pC->isTable==0 );
-    assert( pIn3->flags & MEM_Blob );
-    ExpandBlob(pIn3);
-    u.bb.pIdxKey = sqlite3VdbeRecordUnpack(u.bb.pC->pKeyInfo, pIn3->n, pIn3->z,
-                                      u.bb.aTempRec, sizeof(u.bb.aTempRec));
-    if( u.bb.pIdxKey==0 ){
-      goto no_mem;
-    }
-    if( pOp->opcode==OP_Found ){
+    if( pOp->p4.i>0 ){
+      u.bb.r.pKeyInfo = u.bb.pC->pKeyInfo;
+      u.bb.r.nField = pOp->p4.i;
+      u.bb.r.aMem = pIn3;
+      u.bb.r.flags = UNPACKED_PREFIX_MATCH;
+      u.bb.pIdxKey = &u.bb.r;
+    }else{
+      assert( pIn3->flags & MEM_Blob );
+      ExpandBlob(pIn3);
+      u.bb.pIdxKey = sqlite3VdbeRecordUnpack(u.bb.pC->pKeyInfo, pIn3->n, pIn3->z,
+                                        u.bb.aTempRec, sizeof(u.bb.aTempRec));
+      if( u.bb.pIdxKey==0 ){
+        goto no_mem;
+      }
       u.bb.pIdxKey->flags |= UNPACKED_PREFIX_MATCH;
     }
     rc = sqlite3BtreeMovetoUnpacked(u.bb.pC->pCursor, u.bb.pIdxKey, 0, 0, &u.bb.res);
-    sqlite3VdbeDeleteUnpackedRecord(u.bb.pIdxKey);
+    if( pOp->p4.i==0 ){
+      sqlite3VdbeDeleteUnpackedRecord(u.bb.pIdxKey);
+    }
     if( rc!=SQLITE_OK ){
       break;
     }
     u.bb.alreadyExists = (u.bb.res==0);
     u.bb.pC->deferredMoveto = 0;
@@ -55469,13 +55455,14 @@
   break;
 }
 
 /* Opcode: IsUnique P1 P2 P3 P4 *
 **
-** Cursor P1 is open on an index.  So it has no data and its key consists
-** of a record generated by OP_MakeRecord where the last field is the
-** rowid of the entry that the index refers to.
+** Cursor P1 is open on an index b-tree - that is to say, a btree which
+** no data and where the key are records generated by OP_MakeRecord with
+** the list field being the integer ROWID of the entry that the index
+** entry refers to.
 **
 ** The P3 register contains an integer record number. Call this record
 ** number R. Register P4 is the first in a set of N contiguous registers
 ** that make up an unpacked index key that can be used with cursor P1.
 ** The value of N can be inferred from the cursor. N includes the rowid
@@ -55498,16 +55485,17 @@
 #if 0  /* local variables moved into u.bc */
   u16 ii;
   VdbeCursor *pCx;
   BtCursor *pCrsr;
   u16 nField;
-  Mem *aMem;
+  Mem *aMx;
   UnpackedRecord r;                  /* B-Tree index search key */
   i64 R;                             /* Rowid stored in register P3 */
 #endif /* local variables moved into u.bc */
 
-  u.bc.aMem = &p->aMem[pOp->p4.i];
+  pIn3 = &aMem[pOp->p3];
+  u.bc.aMx = &aMem[pOp->p4.i];
   /* Assert that the values of parameters P1 and P4 are in range. */
   assert( pOp->p4type==P4_INT32 );
   assert( pOp->p4.i>0 && pOp->p4.i<=p->nMem );
   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
 
@@ -55519,24 +55507,24 @@
   u.bc.pCrsr = u.bc.pCx->pCursor;
 
   /* If any of the values are NULL, take the jump. */
   u.bc.nField = u.bc.pCx->pKeyInfo->nField;
   for(u.bc.ii=0; u.bc.ii<u.bc.nField; u.bc.ii++){
-    if( u.bc.aMem[u.bc.ii].flags & MEM_Null ){
+    if( u.bc.aMx[u.bc.ii].flags & MEM_Null ){
       pc = pOp->p2 - 1;
       u.bc.pCrsr = 0;
       break;
     }
   }
-  assert( (u.bc.aMem[u.bc.nField].flags & MEM_Null)==0 );
+  assert( (u.bc.aMx[u.bc.nField].flags & MEM_Null)==0 );
 
   if( u.bc.pCrsr!=0 ){
     /* Populate the index search key. */
     u.bc.r.pKeyInfo = u.bc.pCx->pKeyInfo;
     u.bc.r.nField = u.bc.nField + 1;
     u.bc.r.flags = UNPACKED_PREFIX_SEARCH;
-    u.bc.r.aMem = u.bc.aMem;
+    u.bc.r.aMem = u.bc.aMx;
 
     /* Extract the value of u.bc.R from register P3. */
     sqlite3VdbeMemIntegerify(pIn3);
     u.bc.R = pIn3->u.i;
 
@@ -55573,10 +55561,11 @@
   BtCursor *pCrsr;
   int res;
   u64 iKey;
 #endif /* local variables moved into u.bd */
 
+  pIn3 = &aMem[pOp->p3];
   assert( pIn3->flags & MEM_Int );
   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
   u.bd.pC = p->apCsr[pOp->p1];
   assert( u.bd.pC!=0 );
   assert( u.bd.pC->isTable );
@@ -55616,11 +55605,10 @@
 */
 case OP_Sequence: {           /* out2-prerelease */
   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
   assert( p->apCsr[pOp->p1]!=0 );
   pOut->u.i = p->apCsr[pOp->p1]->seqCount++;
-  MemSetTypeFlag(pOut, MEM_Int);
   break;
 }
 
 
 /* Opcode: NewRowid P1 P2 P3 * *
@@ -55712,11 +55700,11 @@
           assert( pOp->p3<=u.be.pFrame->nMem );
           u.be.pMem = &u.be.pFrame->aMem[pOp->p3];
         }else{
           /* Assert that P3 is a valid memory cell. */
           assert( pOp->p3<=p->nMem );
-          u.be.pMem = &p->aMem[pOp->p3];
+          u.be.pMem = &aMem[pOp->p3];
         }
 
         REGISTER_TRACE(pOp->p3, u.be.pMem);
         sqlite3VdbeMemIntegerify(u.be.pMem);
         assert( (u.be.pMem->flags & MEM_Int)!=0 );  /* mem(P3) holds an integer */
@@ -55755,11 +55743,10 @@
     }
     u.be.pC->rowidIsValid = 0;
     u.be.pC->deferredMoveto = 0;
     u.be.pC->cacheStatus = CACHE_STALE;
   }
-  MemSetTypeFlag(pOut, MEM_Int);
   pOut->u.i = u.be.v;
   break;
 }
 
 /* Opcode: Insert P1 P2 P3 P4 P5
@@ -55818,21 +55805,21 @@
   const char *zDb;  /* database name - used by the update hook */
   const char *zTbl; /* Table name - used by the opdate hook */
   int op;           /* Opcode for update hook: SQLITE_UPDATE or SQLITE_INSERT */
 #endif /* local variables moved into u.bf */
 
-  u.bf.pData = &p->aMem[pOp->p2];
+  u.bf.pData = &aMem[pOp->p2];
   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
   u.bf.pC = p->apCsr[pOp->p1];
   assert( u.bf.pC!=0 );
   assert( u.bf.pC->pCursor!=0 );
   assert( u.bf.pC->pseudoTableReg==0 );
   assert( u.bf.pC->isTable );
   REGISTER_TRACE(pOp->p2, u.bf.pData);
 
   if( pOp->opcode==OP_Insert ){
-    u.bf.pKey = &p->aMem[pOp->p3];
+    u.bf.pKey = &aMem[pOp->p3];
     assert( u.bf.pKey->flags & MEM_Int );
     REGISTER_TRACE(pOp->p3, u.bf.pKey);
     u.bf.iKey = u.bf.pKey->u.i;
   }else{
     assert( pOp->opcode==OP_InsertInt );
@@ -55980,11 +55967,11 @@
   BtCursor *pCrsr;
   u32 n;
   i64 n64;
 #endif /* local variables moved into u.bh */
 
-  pOut = &p->aMem[pOp->p2];
+  pOut = &aMem[pOp->p2];
 
   /* Note that RowKey and RowData are really exactly the same instruction */
   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
   u.bh.pC = p->apCsr[pOp->p1];
   assert( u.bh.pC->isTable || pOp->opcode==OP_RowKey );
@@ -56055,11 +56042,11 @@
   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
   u.bi.pC = p->apCsr[pOp->p1];
   assert( u.bi.pC!=0 );
   assert( u.bi.pC->pseudoTableReg==0 );
   if( u.bi.pC->nullRow ){
-    /* Do nothing so that reg[P2] remains NULL */
+    pOut->flags = MEM_Null;
     break;
   }else if( u.bi.pC->deferredMoveto ){
     u.bi.v = u.bi.pC->movetoTarget;
 #ifndef SQLITE_OMIT_VIRTUALTABLE
   }else if( u.bi.pC->pVtabCursor ){
@@ -56083,11 +56070,10 @@
       rc = sqlite3BtreeKeySize(u.bi.pC->pCursor, &u.bi.v);
       assert( rc==SQLITE_OK );  /* Always so because of CursorMoveto() above */
     }
   }
   pOut->u.i = u.bi.v;
-  MemSetTypeFlag(pOut, MEM_Int);
   break;
 }
 
 /* Opcode: NullRow P1 * * * *
 **
@@ -56278,10 +56264,11 @@
 #endif /* local variables moved into u.bn */
 
   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
   u.bn.pC = p->apCsr[pOp->p1];
   assert( u.bn.pC!=0 );
+  pIn2 = &aMem[pOp->p2];
   assert( pIn2->flags & MEM_Blob );
   u.bn.pCrsr = u.bn.pC->pCursor;
   if( ALWAYS(u.bn.pCrsr!=0) ){
     assert( u.bn.pC->isTable==0 );
     rc = ExpandBlob(pIn2);
@@ -56320,11 +56307,11 @@
   u.bo.pCrsr = u.bo.pC->pCursor;
   if( ALWAYS(u.bo.pCrsr!=0) ){
     u.bo.r.pKeyInfo = u.bo.pC->pKeyInfo;
     u.bo.r.nField = (u16)pOp->p3;
     u.bo.r.flags = 0;
-    u.bo.r.aMem = &p->aMem[pOp->p2];
+    u.bo.r.aMem = &aMem[pOp->p2];
     rc = sqlite3BtreeMovetoUnpacked(u.bo.pCrsr, &u.bo.r, 0, 0, &u.bo.res);
     if( rc==SQLITE_OK && u.bo.res==0 ){
       rc = sqlite3BtreeDelete(u.bo.pCrsr);
     }
     assert( u.bo.pC->deferredMoveto==0 );
@@ -56350,10 +56337,11 @@
 
   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
   u.bp.pC = p->apCsr[pOp->p1];
   assert( u.bp.pC!=0 );
   u.bp.pCrsr = u.bp.pC->pCursor;
+  pOut->flags = MEM_Null;
   if( ALWAYS(u.bp.pCrsr!=0) ){
     rc = sqlite3VdbeCursorMoveto(u.bp.pC);
     if( NEVER(rc) ) goto abort_due_to_error;
     assert( u.bp.pC->deferredMoveto==0 );
     assert( u.bp.pC->isTable==0 );
@@ -56360,12 +56348,12 @@
     if( !u.bp.pC->nullRow ){
       rc = sqlite3VdbeIdxRowid(db, u.bp.pCrsr, &u.bp.rowid);
       if( rc!=SQLITE_OK ){
         goto abort_due_to_error;
       }
-      MemSetTypeFlag(pOut, MEM_Int);
       pOut->u.i = u.bp.rowid;
+      pOut->flags = MEM_Int;
     }
   }
   break;
 }
 
@@ -56393,12 +56381,12 @@
 ** Otherwise fall through to the next instruction.
 **
 ** If P5 is non-zero then the key value is increased by an epsilon prior
 ** to the comparison.  This makes the opcode work like IdxLE.
 */
-case OP_IdxLT:          /* jump, in3 */
-case OP_IdxGE: {        /* jump, in3 */
+case OP_IdxLT:          /* jump */
+case OP_IdxGE: {        /* jump */
 #if 0  /* local variables moved into u.bq */
   VdbeCursor *pC;
   int res;
   UnpackedRecord r;
 #endif /* local variables moved into u.bq */
@@ -56415,11 +56403,11 @@
     if( pOp->p5 ){
       u.bq.r.flags = UNPACKED_INCRKEY | UNPACKED_IGNORE_ROWID;
     }else{
       u.bq.r.flags = UNPACKED_IGNORE_ROWID;
     }
-    u.bq.r.aMem = &p->aMem[pOp->p3];
+    u.bq.r.aMem = &aMem[pOp->p3];
     rc = sqlite3VdbeIdxKeyCompare(u.bq.pC, &u.bq.r, &u.bq.res);
     if( pOp->opcode==OP_IdxLT ){
       u.bq.res = -u.bq.res;
     }else{
       assert( pOp->opcode==OP_IdxGE );
@@ -56467,23 +56455,25 @@
     }
   }
 #else
   u.br.iCnt = db->activeVdbeCnt;
 #endif
+  pOut->flags = MEM_Null;
   if( u.br.iCnt>1 ){
     rc = SQLITE_LOCKED;
     p->errorAction = OE_Abort;
   }else{
     u.br.iDb = pOp->p3;
     assert( u.br.iCnt==1 );
     assert( (p->btreeMask & (1<<u.br.iDb))!=0 );
     rc = sqlite3BtreeDropTable(db->aDb[u.br.iDb].pBt, pOp->p1, &u.br.iMoved);
-    MemSetTypeFlag(pOut, MEM_Int);
+    pOut->flags = MEM_Int;
     pOut->u.i = u.br.iMoved;
 #ifndef SQLITE_OMIT_AUTOVACUUM
     if( rc==SQLITE_OK && u.br.iMoved!=0 ){
       sqlite3RootPageMoved(&db->aDb[u.br.iDb], u.br.iMoved, pOp->p1);
+      resetSchemaOnFault = 1;
     }
 #endif
   }
   break;
 }
@@ -56517,11 +56507,11 @@
       db->aDb[pOp->p2].pBt, pOp->p1, (pOp->p3 ? &u.bs.nChange : 0)
   );
   if( pOp->p3 ){
     p->nChange += u.bs.nChange;
     if( pOp->p3>0 ){
-      p->aMem[pOp->p3].u.i += u.bs.nChange;
+      aMem[pOp->p3].u.i += u.bs.nChange;
     }
   }
   break;
 }
 
@@ -56566,11 +56556,10 @@
   }else{
     u.bt.flags = BTREE_ZERODATA;
   }
   rc = sqlite3BtreeCreateTable(u.bt.pDb->pBt, &u.bt.pgno, u.bt.flags);
   pOut->u.i = u.bt.pgno;
-  MemSetTypeFlag(pOut, MEM_Int);
   break;
 }
 
 /* Opcode: ParseSchema P1 P2 * P4 *
 **
@@ -56733,14 +56722,14 @@
   u.bv.nRoot = pOp->p2;
   assert( u.bv.nRoot>0 );
   u.bv.aRoot = sqlite3DbMallocRaw(db, sizeof(int)*(u.bv.nRoot+1) );
   if( u.bv.aRoot==0 ) goto no_mem;
   assert( pOp->p3>0 && pOp->p3<=p->nMem );
-  u.bv.pnErr = &p->aMem[pOp->p3];
+  u.bv.pnErr = &aMem[pOp->p3];
   assert( (u.bv.pnErr->flags & MEM_Int)!=0 );
   assert( (u.bv.pnErr->flags & (MEM_Str|MEM_Blob))==0 );
-  pIn1 = &p->aMem[pOp->p1];
+  pIn1 = &aMem[pOp->p1];
   for(u.bv.j=0; u.bv.j<u.bv.nRoot; u.bv.j++){
     u.bv.aRoot[u.bv.j] = (int)sqlite3VdbeIntValue(&pIn1[u.bv.j]);
   }
   u.bv.aRoot[u.bv.j] = 0;
   assert( pOp->p5<db->nDb );
@@ -56768,53 +56757,43 @@
 ** Insert the integer value held by register P2 into a boolean index
 ** held in register P1.
 **
 ** An assertion fails if P2 is not an integer.
 */
-case OP_RowSetAdd: {       /* in2 */
-#if 0  /* local variables moved into u.bw */
-  Mem *pIdx;
-  Mem *pVal;
-#endif /* local variables moved into u.bw */
-  assert( pOp->p1>0 && pOp->p1<=p->nMem );
-  u.bw.pIdx = &p->aMem[pOp->p1];
-  assert( pOp->p2>0 && pOp->p2<=p->nMem );
-  u.bw.pVal = &p->aMem[pOp->p2];
-  assert( (u.bw.pVal->flags & MEM_Int)!=0 );
-  if( (u.bw.pIdx->flags & MEM_RowSet)==0 ){
-    sqlite3VdbeMemSetRowSet(u.bw.pIdx);
-    if( (u.bw.pIdx->flags & MEM_RowSet)==0 ) goto no_mem;
-  }
-  sqlite3RowSetInsert(u.bw.pIdx->u.pRowSet, u.bw.pVal->u.i);
+case OP_RowSetAdd: {       /* in1, in2 */
+  pIn1 = &aMem[pOp->p1];
+  pIn2 = &aMem[pOp->p2];
+  assert( (pIn2->flags & MEM_Int)!=0 );
+  if( (pIn1->flags & MEM_RowSet)==0 ){
+    sqlite3VdbeMemSetRowSet(pIn1);
+    if( (pIn1->flags & MEM_RowSet)==0 ) goto no_mem;
+  }
+  sqlite3RowSetInsert(pIn1->u.pRowSet, pIn2->u.i);
   break;
 }
 
 /* Opcode: RowSetRead P1 P2 P3 * *
 **
 ** Extract the smallest value from boolean index P1 and put that value into
 ** register P3.  Or, if boolean index P1 is initially empty, leave P3
 ** unchanged and jump to instruction P2.
 */
-case OP_RowSetRead: {       /* jump, out3 */
-#if 0  /* local variables moved into u.bx */
-  Mem *pIdx;
+case OP_RowSetRead: {       /* jump, in1, out3 */
+#if 0  /* local variables moved into u.bw */
   i64 val;
-#endif /* local variables moved into u.bx */
-  assert( pOp->p1>0 && pOp->p1<=p->nMem );
+#endif /* local variables moved into u.bw */
   CHECK_FOR_INTERRUPT;
-  u.bx.pIdx = &p->aMem[pOp->p1];
-  pOut = &p->aMem[pOp->p3];
-  if( (u.bx.pIdx->flags & MEM_RowSet)==0
-   || sqlite3RowSetNext(u.bx.pIdx->u.pRowSet, &u.bx.val)==0
+  pIn1 = &aMem[pOp->p1];
+  if( (pIn1->flags & MEM_RowSet)==0
+   || sqlite3RowSetNext(pIn1->u.pRowSet, &u.bw.val)==0
   ){
     /* The boolean index is empty */
-    sqlite3VdbeMemSetNull(u.bx.pIdx);
+    sqlite3VdbeMemSetNull(pIn1);
     pc = pOp->p2 - 1;
   }else{
     /* A value was pulled from the index */
-    assert( pOp->p3>0 && pOp->p3<=p->nMem );
-    sqlite3VdbeMemSetInt64(pOut, u.bx.val);
+    sqlite3VdbeMemSetInt64(&aMem[pOp->p3], u.bw.val);
   }
   break;
 }
 
 /* Opcode: RowSetTest P1 P2 P3 P4
@@ -56839,16 +56818,18 @@
 ** inserted, there is no need to search to see if the same value was
 ** previously inserted as part of set X (only if it was previously
 ** inserted as part of some other set).
 */
 case OP_RowSetTest: {                     /* jump, in1, in3 */
-#if 0  /* local variables moved into u.by */
+#if 0  /* local variables moved into u.bx */
   int iSet;
   int exists;
-#endif /* local variables moved into u.by */
-
-  u.by.iSet = pOp->p4.i;
+#endif /* local variables moved into u.bx */
+
+  pIn1 = &aMem[pOp->p1];
+  pIn3 = &aMem[pOp->p3];
+  u.bx.iSet = pOp->p4.i;
   assert( pIn3->flags&MEM_Int );
 
   /* If there is anything other than a rowset object in memory cell P1,
   ** delete it now and initialize P1 with an empty rowset
   */
@@ -56856,21 +56837,21 @@
     sqlite3VdbeMemSetRowSet(pIn1);
     if( (pIn1->flags & MEM_RowSet)==0 ) goto no_mem;
   }
 
   assert( pOp->p4type==P4_INT32 );
-  assert( u.by.iSet==-1 || u.by.iSet>=0 );
-  if( u.by.iSet ){
-    u.by.exists = sqlite3RowSetTest(pIn1->u.pRowSet,
-                               (u8)(u.by.iSet>=0 ? u.by.iSet & 0xf : 0xff),
+  assert( u.bx.iSet==-1 || u.bx.iSet>=0 );
+  if( u.bx.iSet ){
+    u.bx.exists = sqlite3RowSetTest(pIn1->u.pRowSet,
+                               (u8)(u.bx.iSet>=0 ? u.bx.iSet & 0xf : 0xff),
                                pIn3->u.i);
-    if( u.by.exists ){
+    if( u.bx.exists ){
       pc = pOp->p2 - 1;
       break;
     }
   }
-  if( u.by.iSet>=0 ){
+  if( u.bx.iSet>=0 ){
     sqlite3RowSetInsert(pIn1->u.pRowSet, pIn3->u.i);
   }
   break;
 }
 
@@ -56889,24 +56870,24 @@
 ** memory required by the sub-vdbe at runtime.
 **
 ** P4 is a pointer to the VM containing the trigger program.
 */
 case OP_Program: {        /* jump */
-#if 0  /* local variables moved into u.bz */
+#if 0  /* local variables moved into u.by */
   int nMem;               /* Number of memory registers for sub-program */
   int nByte;              /* Bytes of runtime space required for sub-program */
   Mem *pRt;               /* Register to allocate runtime space */
   Mem *pMem;              /* Used to iterate through memory cells */
   Mem *pEnd;              /* Last memory cell in new array */
   VdbeFrame *pFrame;      /* New vdbe frame to execute in */
   SubProgram *pProgram;   /* Sub-program to execute */
   void *t;                /* Token identifying trigger */
-#endif /* local variables moved into u.bz */
-
-  u.bz.pProgram = pOp->p4.pProgram;
-  u.bz.pRt = &p->aMem[pOp->p3];
-  assert( u.bz.pProgram->nOp>0 );
+#endif /* local variables moved into u.by */
+
+  u.by.pProgram = pOp->p4.pProgram;
+  u.by.pRt = &aMem[pOp->p3];
+  assert( u.by.pProgram->nOp>0 );
 
   /* If the p5 flag is clear, then recursive invocation of triggers is
   ** disabled for backwards compatibility (p5 is set if this sub-program
   ** is really a trigger, not a foreign key action, and the flag set
   ** and cleared by the "PRAGMA recursive_triggers" command is clear).
@@ -56916,79 +56897,79 @@
   ** SubProgram (if the trigger may be executed with more than one different
   ** ON CONFLICT algorithm). SubProgram structures associated with a
   ** single trigger all have the same value for the SubProgram.token
   ** variable.  */
   if( pOp->p5 ){
-    u.bz.t = u.bz.pProgram->token;
-    for(u.bz.pFrame=p->pFrame; u.bz.pFrame && u.bz.pFrame->token!=u.bz.t; u.bz.pFrame=u.bz.pFrame->pParent);
-    if( u.bz.pFrame ) break;
+    u.by.t = u.by.pProgram->token;
+    for(u.by.pFrame=p->pFrame; u.by.pFrame && u.by.pFrame->token!=u.by.t; u.by.pFrame=u.by.pFrame->pParent);
+    if( u.by.pFrame ) break;
   }
 
   if( p->nFrame>=db->aLimit[SQLITE_LIMIT_TRIGGER_DEPTH] ){
     rc = SQLITE_ERROR;
     sqlite3SetString(&p->zErrMsg, db, "too many levels of trigger recursion");
     break;
   }
 
-  /* Register u.bz.pRt is used to store the memory required to save the state
+  /* Register u.by.pRt is used to store the memory required to save the state
   ** of the current program, and the memory required at runtime to execute
-  ** the trigger program. If this trigger has been fired before, then u.bz.pRt
+  ** the trigger program. If this trigger has been fired before, then u.by.pRt
   ** is already allocated. Otherwise, it must be initialized.  */
-  if( (u.bz.pRt->flags&MEM_Frame)==0 ){
+  if( (u.by.pRt->flags&MEM_Frame)==0 ){
     /* SubProgram.nMem is set to the number of memory cells used by the
     ** program stored in SubProgram.aOp. As well as these, one memory
     ** cell is required for each cursor used by the program. Set local
-    ** variable u.bz.nMem (and later, VdbeFrame.nChildMem) to this value.
-    */
-    u.bz.nMem = u.bz.pProgram->nMem + u.bz.pProgram->nCsr;
-    u.bz.nByte = ROUND8(sizeof(VdbeFrame))
-              + u.bz.nMem * sizeof(Mem)
-              + u.bz.pProgram->nCsr * sizeof(VdbeCursor *);
-    u.bz.pFrame = sqlite3DbMallocZero(db, u.bz.nByte);
-    if( !u.bz.pFrame ){
+    ** variable u.by.nMem (and later, VdbeFrame.nChildMem) to this value.
+    */
+    u.by.nMem = u.by.pProgram->nMem + u.by.pProgram->nCsr;
+    u.by.nByte = ROUND8(sizeof(VdbeFrame))
+              + u.by.nMem * sizeof(Mem)
+              + u.by.pProgram->nCsr * sizeof(VdbeCursor *);
+    u.by.pFrame = sqlite3DbMallocZero(db, u.by.nByte);
+    if( !u.by.pFrame ){
       goto no_mem;
     }
-    sqlite3VdbeMemRelease(u.bz.pRt);
-    u.bz.pRt->flags = MEM_Frame;
-    u.bz.pRt->u.pFrame = u.bz.pFrame;
-
-    u.bz.pFrame->v = p;
-    u.bz.pFrame->nChildMem = u.bz.nMem;
-    u.bz.pFrame->nChildCsr = u.bz.pProgram->nCsr;
-    u.bz.pFrame->pc = pc;
-    u.bz.pFrame->aMem = p->aMem;
-    u.bz.pFrame->nMem = p->nMem;
-    u.bz.pFrame->apCsr = p->apCsr;
-    u.bz.pFrame->nCursor = p->nCursor;
-    u.bz.pFrame->aOp = p->aOp;
-    u.bz.pFrame->nOp = p->nOp;
-    u.bz.pFrame->token = u.bz.pProgram->token;
-
-    u.bz.pEnd = &VdbeFrameMem(u.bz.pFrame)[u.bz.pFrame->nChildMem];
-    for(u.bz.pMem=VdbeFrameMem(u.bz.pFrame); u.bz.pMem!=u.bz.pEnd; u.bz.pMem++){
-      u.bz.pMem->flags = MEM_Null;
-      u.bz.pMem->db = db;
-    }
-  }else{
-    u.bz.pFrame = u.bz.pRt->u.pFrame;
-    assert( u.bz.pProgram->nMem+u.bz.pProgram->nCsr==u.bz.pFrame->nChildMem );
-    assert( u.bz.pProgram->nCsr==u.bz.pFrame->nChildCsr );
-    assert( pc==u.bz.pFrame->pc );
+    sqlite3VdbeMemRelease(u.by.pRt);
+    u.by.pRt->flags = MEM_Frame;
+    u.by.pRt->u.pFrame = u.by.pFrame;
+
+    u.by.pFrame->v = p;
+    u.by.pFrame->nChildMem = u.by.nMem;
+    u.by.pFrame->nChildCsr = u.by.pProgram->nCsr;
+    u.by.pFrame->pc = pc;
+    u.by.pFrame->aMem = p->aMem;
+    u.by.pFrame->nMem = p->nMem;
+    u.by.pFrame->apCsr = p->apCsr;
+    u.by.pFrame->nCursor = p->nCursor;
+    u.by.pFrame->aOp = p->aOp;
+    u.by.pFrame->nOp = p->nOp;
+    u.by.pFrame->token = u.by.pProgram->token;
+
+    u.by.pEnd = &VdbeFrameMem(u.by.pFrame)[u.by.pFrame->nChildMem];
+    for(u.by.pMem=VdbeFrameMem(u.by.pFrame); u.by.pMem!=u.by.pEnd; u.by.pMem++){
+      u.by.pMem->flags = MEM_Null;
+      u.by.pMem->db = db;
+    }
+  }else{
+    u.by.pFrame = u.by.pRt->u.pFrame;
+    assert( u.by.pProgram->nMem+u.by.pProgram->nCsr==u.by.pFrame->nChildMem );
+    assert( u.by.pProgram->nCsr==u.by.pFrame->nChildCsr );
+    assert( pc==u.by.pFrame->pc );
   }
 
   p->nFrame++;
-  u.bz.pFrame->pParent = p->pFrame;
-  u.bz.pFrame->lastRowid = db->lastRowid;
-  u.bz.pFrame->nChange = p->nChange;
+  u.by.pFrame->pParent = p->pFrame;
+  u.by.pFrame->lastRowid = db->lastRowid;
+  u.by.pFrame->nChange = p->nChange;
   p->nChange = 0;
-  p->pFrame = u.bz.pFrame;
-  p->aMem = &VdbeFrameMem(u.bz.pFrame)[-1];
-  p->nMem = u.bz.pFrame->nChildMem;
-  p->nCursor = (u16)u.bz.pFrame->nChildCsr;
-  p->apCsr = (VdbeCursor **)&p->aMem[p->nMem+1];
-  p->aOp = u.bz.pProgram->aOp;
-  p->nOp = u.bz.pProgram->nOp;
+  p->pFrame = u.by.pFrame;
+  p->aMem = aMem = &VdbeFrameMem(u.by.pFrame)[-1];
+  p->nMem = u.by.pFrame->nChildMem;
+  p->nCursor = (u16)u.by.pFrame->nChildCsr;
+  p->apCsr = (VdbeCursor **)&aMem[p->nMem+1];
+  p->aOp = aOp = u.by.pProgram->aOp;
+  p->nOp = u.by.pProgram->nOp;
   pc = -1;
 
   break;
 }
 
@@ -57003,17 +56984,17 @@
 ** The address of the cell in the parent frame is determined by adding
 ** the value of the P1 argument to the value of the P1 argument to the
 ** calling OP_Program instruction.
 */
 case OP_Param: {           /* out2-prerelease */
-#if 0  /* local variables moved into u.ca */
+#if 0  /* local variables moved into u.bz */
   VdbeFrame *pFrame;
   Mem *pIn;
-#endif /* local variables moved into u.ca */
-  u.ca.pFrame = p->pFrame;
-  u.ca.pIn = &u.ca.pFrame->aMem[pOp->p1 + u.ca.pFrame->aOp[u.ca.pFrame->pc].p1];
-  sqlite3VdbeMemShallowCopy(pOut, u.ca.pIn, MEM_Ephem);
+#endif /* local variables moved into u.bz */
+  u.bz.pFrame = p->pFrame;
+  u.bz.pIn = &u.bz.pFrame->aMem[pOp->p1 + u.bz.pFrame->aOp[u.bz.pFrame->pc].p1];
+  sqlite3VdbeMemShallowCopy(pOut, u.bz.pIn, MEM_Ephem);
   break;
 }
 
 #endif /* #ifndef SQLITE_OMIT_TRIGGER */
 
@@ -57065,24 +57046,25 @@
 **
 ** This instruction throws an error if the memory cell is not initially
 ** an integer.
 */
 case OP_MemMax: {        /* in2 */
-#if 0  /* local variables moved into u.cb */
+#if 0  /* local variables moved into u.ca */
   Mem *pIn1;
   VdbeFrame *pFrame;
-#endif /* local variables moved into u.cb */
+#endif /* local variables moved into u.ca */
   if( p->pFrame ){
-    for(u.cb.pFrame=p->pFrame; u.cb.pFrame->pParent; u.cb.pFrame=u.cb.pFrame->pParent);
-    u.cb.pIn1 = &u.cb.pFrame->aMem[pOp->p1];
-  }else{
-    u.cb.pIn1 = &p->aMem[pOp->p1];
-  }
-  sqlite3VdbeMemIntegerify(u.cb.pIn1);
+    for(u.ca.pFrame=p->pFrame; u.ca.pFrame->pParent; u.ca.pFrame=u.ca.pFrame->pParent);
+    u.ca.pIn1 = &u.ca.pFrame->aMem[pOp->p1];
+  }else{
+    u.ca.pIn1 = &aMem[pOp->p1];
+  }
+  sqlite3VdbeMemIntegerify(u.ca.pIn1);
+  pIn2 = &aMem[pOp->p2];
   sqlite3VdbeMemIntegerify(pIn2);
-  if( u.cb.pIn1->u.i<pIn2->u.i){
-    u.cb.pIn1->u.i = pIn2->u.i;
+  if( u.ca.pIn1->u.i<pIn2->u.i){
+    u.ca.pIn1->u.i = pIn2->u.i;
   }
   break;
 }
 #endif /* SQLITE_OMIT_AUTOINCREMENT */
 
@@ -57092,10 +57074,11 @@
 **
 ** It is illegal to use this instruction on a register that does
 ** not contain an integer.  An assertion fault will result if you try.
 */
 case OP_IfPos: {        /* jump, in1 */
+  pIn1 = &aMem[pOp->p1];
   assert( pIn1->flags&MEM_Int );
   if( pIn1->u.i>0 ){
      pc = pOp->p2 - 1;
   }
   break;
@@ -57107,26 +57090,30 @@
 **
 ** It is illegal to use this instruction on a register that does
 ** not contain an integer.  An assertion fault will result if you try.
 */
 case OP_IfNeg: {        /* jump, in1 */
+  pIn1 = &aMem[pOp->p1];
   assert( pIn1->flags&MEM_Int );
   if( pIn1->u.i<0 ){
      pc = pOp->p2 - 1;
   }
   break;
 }
 
-/* Opcode: IfZero P1 P2 * * *
-**
-** If the value of register P1 is exactly 0, jump to P2.
+/* Opcode: IfZero P1 P2 P3 * *
+**
+** The register P1 must contain an integer.  Add literal P3 to the
+** value in register P1.  If the result is exactly 0, jump to P2.
 **
 ** It is illegal to use this instruction on a register that does
 ** not contain an integer.  An assertion fault will result if you try.
 */
 case OP_IfZero: {        /* jump, in1 */
+  pIn1 = &aMem[pOp->p1];
   assert( pIn1->flags&MEM_Int );
+  pIn1->u.i += pOp->p3;
   if( pIn1->u.i==0 ){
      pc = pOp->p2 - 1;
   }
   break;
 }
@@ -57140,51 +57127,51 @@
 **
 ** The P5 arguments are taken from register P2 and its
 ** successors.
 */
 case OP_AggStep: {
-#if 0  /* local variables moved into u.cc */
+#if 0  /* local variables moved into u.cb */
   int n;
   int i;
   Mem *pMem;
   Mem *pRec;
   sqlite3_context ctx;
   sqlite3_value **apVal;
-#endif /* local variables moved into u.cc */
-
-  u.cc.n = pOp->p5;
-  assert( u.cc.n>=0 );
-  u.cc.pRec = &p->aMem[pOp->p2];
-  u.cc.apVal = p->apArg;
-  assert( u.cc.apVal || u.cc.n==0 );
-  for(u.cc.i=0; u.cc.i<u.cc.n; u.cc.i++, u.cc.pRec++){
-    u.cc.apVal[u.cc.i] = u.cc.pRec;
-    sqlite3VdbeMemStoreType(u.cc.pRec);
-  }
-  u.cc.ctx.pFunc = pOp->p4.pFunc;
+#endif /* local variables moved into u.cb */
+
+  u.cb.n = pOp->p5;
+  assert( u.cb.n>=0 );
+  u.cb.pRec = &aMem[pOp->p2];
+  u.cb.apVal = p->apArg;
+  assert( u.cb.apVal || u.cb.n==0 );
+  for(u.cb.i=0; u.cb.i<u.cb.n; u.cb.i++, u.cb.pRec++){
+    u.cb.apVal[u.cb.i] = u.cb.pRec;
+    sqlite3VdbeMemStoreType(u.cb.pRec);
+  }
+  u.cb.ctx.pFunc = pOp->p4.pFunc;
   assert( pOp->p3>0 && pOp->p3<=p->nMem );
-  u.cc.ctx.pMem = u.cc.pMem = &p->aMem[pOp->p3];
-  u.cc.pMem->n++;
-  u.cc.ctx.s.flags = MEM_Null;
-  u.cc.ctx.s.z = 0;
-  u.cc.ctx.s.zMalloc = 0;
-  u.cc.ctx.s.xDel = 0;
-  u.cc.ctx.s.db = db;
-  u.cc.ctx.isError = 0;
-  u.cc.ctx.pColl = 0;
-  if( u.cc.ctx.pFunc->flags & SQLITE_FUNC_NEEDCOLL ){
+  u.cb.ctx.pMem = u.cb.pMem = &aMem[pOp->p3];
+  u.cb.pMem->n++;
+  u.cb.ctx.s.flags = MEM_Null;
+  u.cb.ctx.s.z = 0;
+  u.cb.ctx.s.zMalloc = 0;
+  u.cb.ctx.s.xDel = 0;
+  u.cb.ctx.s.db = db;
+  u.cb.ctx.isError = 0;
+  u.cb.ctx.pColl = 0;
+  if( u.cb.ctx.pFunc->flags & SQLITE_FUNC_NEEDCOLL ){
     assert( pOp>p->aOp );
     assert( pOp[-1].p4type==P4_COLLSEQ );
     assert( pOp[-1].opcode==OP_CollSeq );
-    u.cc.ctx.pColl = pOp[-1].p4.pColl;
-  }
-  (u.cc.ctx.pFunc->xStep)(&u.cc.ctx, u.cc.n, u.cc.apVal);
-  if( u.cc.ctx.isError ){
-    sqlite3SetString(&p->zErrMsg, db, "%s", sqlite3_value_text(&u.cc.ctx.s));
-    rc = u.cc.ctx.isError;
-  }
-  sqlite3VdbeMemRelease(&u.cc.ctx.s);
+    u.cb.ctx.pColl = pOp[-1].p4.pColl;
+  }
+  (u.cb.ctx.pFunc->xStep)(&u.cb.ctx, u.cb.n, u.cb.apVal);
+  if( u.cb.ctx.isError ){
+    sqlite3SetString(&p->zErrMsg, db, "%s", sqlite3_value_text(&u.cb.ctx.s));
+    rc = u.cb.ctx.isError;
+  }
+  sqlite3VdbeMemRelease(&u.cb.ctx.s);
   break;
 }
 
 /* Opcode: AggFinal P1 P2 * P4 *
 **
@@ -57197,23 +57184,23 @@
 ** functions that can take varying numbers of arguments.  The
 ** P4 argument is only needed for the degenerate case where
 ** the step function was not previously called.
 */
 case OP_AggFinal: {
-#if 0  /* local variables moved into u.cd */
+#if 0  /* local variables moved into u.cc */
   Mem *pMem;
-#endif /* local variables moved into u.cd */
+#endif /* local variables moved into u.cc */
   assert( pOp->p1>0 && pOp->p1<=p->nMem );
-  u.cd.pMem = &p->aMem[pOp->p1];
-  assert( (u.cd.pMem->flags & ~(MEM_Null|MEM_Agg))==0 );
-  rc = sqlite3VdbeMemFinalize(u.cd.pMem, pOp->p4.pFunc);
+  u.cc.pMem = &aMem[pOp->p1];
+  assert( (u.cc.pMem->flags & ~(MEM_Null|MEM_Agg))==0 );
+  rc = sqlite3VdbeMemFinalize(u.cc.pMem, pOp->p4.pFunc);
   if( rc ){
-    sqlite3SetString(&p->zErrMsg, db, "%s", sqlite3_value_text(u.cd.pMem));
-  }
-  sqlite3VdbeChangeEncoding(u.cd.pMem, encoding);
-  UPDATE_MAX_BLOBSIZE(u.cd.pMem);
-  if( sqlite3VdbeMemTooBig(u.cd.pMem) ){
+    sqlite3SetString(&p->zErrMsg, db, "%s", sqlite3_value_text(u.cc.pMem));
+  }
+  sqlite3VdbeChangeEncoding(u.cc.pMem, encoding);
+  UPDATE_MAX_BLOBSIZE(u.cc.pMem);
+  if( sqlite3VdbeMemTooBig(u.cc.pMem) ){
     goto too_big;
   }
   break;
 }
 
@@ -57239,18 +57226,18 @@
 ** Perform a single step of the incremental vacuum procedure on
 ** the P1 database. If the vacuum has finished, jump to instruction
 ** P2. Otherwise, fall through to the next instruction.
 */
 case OP_IncrVacuum: {        /* jump */
-#if 0  /* local variables moved into u.ce */
+#if 0  /* local variables moved into u.cd */
   Btree *pBt;
-#endif /* local variables moved into u.ce */
+#endif /* local variables moved into u.cd */
 
   assert( pOp->p1>=0 && pOp->p1<db->nDb );
   assert( (p->btreeMask & (1<<pOp->p1))!=0 );
-  u.ce.pBt = db->aDb[pOp->p1].pBt;
-  rc = sqlite3BtreeIncrVacuum(u.ce.pBt);
+  u.cd.pBt = db->aDb[pOp->p1].pBt;
+  rc = sqlite3BtreeIncrVacuum(u.cd.pBt);
   if( rc==SQLITE_DONE ){
     pc = pOp->p2 - 1;
     rc = SQLITE_OK;
   }
   break;
@@ -57316,19 +57303,19 @@
 ** Also, whether or not P4 is set, check that this is not being called from
 ** within a callback to a virtual table xSync() method. If it is, the error
 ** code will be set to SQLITE_LOCKED.
 */
 case OP_VBegin: {
-#if 0  /* local variables moved into u.cf */
+#if 0  /* local variables moved into u.ce */
   VTable *pVTab;
-#endif /* local variables moved into u.cf */
-  u.cf.pVTab = pOp->p4.pVtab;
-  rc = sqlite3VtabBegin(db, u.cf.pVTab);
-  if( u.cf.pVTab ){
+#endif /* local variables moved into u.ce */
+  u.ce.pVTab = pOp->p4.pVtab;
+  rc = sqlite3VtabBegin(db, u.ce.pVTab);
+  if( u.ce.pVTab ){
     sqlite3DbFree(db, p->zErrMsg);
-    p->zErrMsg = u.cf.pVTab->pVtab->zErrMsg;
-    u.cf.pVTab->pVtab->zErrMsg = 0;
+    p->zErrMsg = u.ce.pVTab->pVtab->zErrMsg;
+    u.ce.pVTab->pVtab->zErrMsg = 0;
   }
   break;
 }
 #endif /* SQLITE_OMIT_VIRTUALTABLE */
 
@@ -57364,40 +57351,40 @@
 ** P4 is a pointer to a virtual table object, an sqlite3_vtab structure.
 ** P1 is a cursor number.  This opcode opens a cursor to the virtual
 ** table and stores that cursor in P1.
 */
 case OP_VOpen: {
-#if 0  /* local variables moved into u.cg */
+#if 0  /* local variables moved into u.cf */
   VdbeCursor *pCur;
   sqlite3_vtab_cursor *pVtabCursor;
   sqlite3_vtab *pVtab;
   sqlite3_module *pModule;
-#endif /* local variables moved into u.cg */
-
-  u.cg.pCur = 0;
-  u.cg.pVtabCursor = 0;
-  u.cg.pVtab = pOp->p4.pVtab->pVtab;
-  u.cg.pModule = (sqlite3_module *)u.cg.pVtab->pModule;
-  assert(u.cg.pVtab && u.cg.pModule);
+#endif /* local variables moved into u.cf */
+
+  u.cf.pCur = 0;
+  u.cf.pVtabCursor = 0;
+  u.cf.pVtab = pOp->p4.pVtab->pVtab;
+  u.cf.pModule = (sqlite3_module *)u.cf.pVtab->pModule;
+  assert(u.cf.pVtab && u.cf.pModule);
   if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
-  rc = u.cg.pModule->xOpen(u.cg.pVtab, &u.cg.pVtabCursor);
+  rc = u.cf.pModule->xOpen(u.cf.pVtab, &u.cf.pVtabCursor);
   sqlite3DbFree(db, p->zErrMsg);
-  p->zErrMsg = u.cg.pVtab->zErrMsg;
-  u.cg.pVtab->zErrMsg = 0;
+  p->zErrMsg = u.cf.pVtab->zErrMsg;
+  u.cf.pVtab->zErrMsg = 0;
   if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
   if( SQLITE_OK==rc ){
     /* Initialize sqlite3_vtab_cursor base class */
-    u.cg.pVtabCursor->pVtab = u.cg.pVtab;
+    u.cf.pVtabCursor->pVtab = u.cf.pVtab;
 
     /* Initialise vdbe cursor object */
-    u.cg.pCur = allocateCursor(p, pOp->p1, 0, -1, 0);
-    if( u.cg.pCur ){
-      u.cg.pCur->pVtabCursor = u.cg.pVtabCursor;
-      u.cg.pCur->pModule = u.cg.pVtabCursor->pVtab->pModule;
+    u.cf.pCur = allocateCursor(p, pOp->p1, 0, -1, 0);
+    if( u.cf.pCur ){
+      u.cf.pCur->pVtabCursor = u.cf.pVtabCursor;
+      u.cf.pCur->pModule = u.cf.pVtabCursor->pVtab->pModule;
     }else{
       db->mallocFailed = 1;
-      u.cg.pModule->xClose(u.cg.pVtabCursor);
+      u.cf.pModule->xClose(u.cf.pVtabCursor);
     }
   }
   break;
 }
 #endif /* SQLITE_OMIT_VIRTUALTABLE */
@@ -57420,11 +57407,11 @@
 ** xFilter as argv. Register P3+2 becomes argv[0] when passed to xFilter.
 **
 ** A jump is made to P2 if the result set after filtering would be empty.
 */
 case OP_VFilter: {   /* jump */
-#if 0  /* local variables moved into u.ch */
+#if 0  /* local variables moved into u.cg */
   int nArg;
   int iQuery;
   const sqlite3_module *pModule;
   Mem *pQuery;
   Mem *pArgc;
@@ -57432,52 +57419,52 @@
   sqlite3_vtab *pVtab;
   VdbeCursor *pCur;
   int res;
   int i;
   Mem **apArg;
-#endif /* local variables moved into u.ch */
-
-  u.ch.pQuery = &p->aMem[pOp->p3];
-  u.ch.pArgc = &u.ch.pQuery[1];
-  u.ch.pCur = p->apCsr[pOp->p1];
-  REGISTER_TRACE(pOp->p3, u.ch.pQuery);
-  assert( u.ch.pCur->pVtabCursor );
-  u.ch.pVtabCursor = u.ch.pCur->pVtabCursor;
-  u.ch.pVtab = u.ch.pVtabCursor->pVtab;
-  u.ch.pModule = u.ch.pVtab->pModule;
+#endif /* local variables moved into u.cg */
+
+  u.cg.pQuery = &aMem[pOp->p3];
+  u.cg.pArgc = &u.cg.pQuery[1];
+  u.cg.pCur = p->apCsr[pOp->p1];
+  REGISTER_TRACE(pOp->p3, u.cg.pQuery);
+  assert( u.cg.pCur->pVtabCursor );
+  u.cg.pVtabCursor = u.cg.pCur->pVtabCursor;
+  u.cg.pVtab = u.cg.pVtabCursor->pVtab;
+  u.cg.pModule = u.cg.pVtab->pModule;
 
   /* Grab the index number and argc parameters */
-  assert( (u.ch.pQuery->flags&MEM_Int)!=0 && u.ch.pArgc->flags==MEM_Int );
-  u.ch.nArg = (int)u.ch.pArgc->u.i;
-  u.ch.iQuery = (int)u.ch.pQuery->u.i;
+  assert( (u.cg.pQuery->flags&MEM_Int)!=0 && u.cg.pArgc->flags==MEM_Int );
+  u.cg.nArg = (int)u.cg.pArgc->u.i;
+  u.cg.iQuery = (int)u.cg.pQuery->u.i;
 
   /* Invoke the xFilter method */
   {
-    u.ch.res = 0;
-    u.ch.apArg = p->apArg;
-    for(u.ch.i = 0; u.ch.i<u.ch.nArg; u.ch.i++){
-      u.ch.apArg[u.ch.i] = &u.ch.pArgc[u.ch.i+1];
-      sqlite3VdbeMemStoreType(u.ch.apArg[u.ch.i]);
+    u.cg.res = 0;
+    u.cg.apArg = p->apArg;
+    for(u.cg.i = 0; u.cg.i<u.cg.nArg; u.cg.i++){
+      u.cg.apArg[u.cg.i] = &u.cg.pArgc[u.cg.i+1];
+      sqlite3VdbeMemStoreType(u.cg.apArg[u.cg.i]);
     }
 
     if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
     p->inVtabMethod = 1;
-    rc = u.ch.pModule->xFilter(u.ch.pVtabCursor, u.ch.iQuery, pOp->p4.z, u.ch.nArg, u.ch.apArg);
+    rc = u.cg.pModule->xFilter(u.cg.pVtabCursor, u.cg.iQuery, pOp->p4.z, u.cg.nArg, u.cg.apArg);
     p->inVtabMethod = 0;
     sqlite3DbFree(db, p->zErrMsg);
-    p->zErrMsg = u.ch.pVtab->zErrMsg;
-    u.ch.pVtab->zErrMsg = 0;
-    if( rc==SQLITE_OK ){
-      u.ch.res = u.ch.pModule->xEof(u.ch.pVtabCursor);
+    p->zErrMsg = u.cg.pVtab->zErrMsg;
+    u.cg.pVtab->zErrMsg = 0;
+    if( rc==SQLITE_OK ){
+      u.cg.res = u.cg.pModule->xEof(u.cg.pVtabCursor);
     }
     if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
 
-    if( u.ch.res ){
+    if( u.cg.res ){
       pc = pOp->p2 - 1;
     }
   }
-  u.ch.pCur->nullRow = 0;
+  u.cg.pCur->nullRow = 0;
 
   break;
 }
 #endif /* SQLITE_OMIT_VIRTUALTABLE */
 
@@ -57487,60 +57474,60 @@
 ** Store the value of the P2-th column of
 ** the row of the virtual-table that the
 ** P1 cursor is pointing to into register P3.
 */
 case OP_VColumn: {
-#if 0  /* local variables moved into u.ci */
+#if 0  /* local variables moved into u.ch */
   sqlite3_vtab *pVtab;
   const sqlite3_module *pModule;
   Mem *pDest;
   sqlite3_context sContext;
-#endif /* local variables moved into u.ci */
+#endif /* local variables moved into u.ch */
 
   VdbeCursor *pCur = p->apCsr[pOp->p1];
   assert( pCur->pVtabCursor );
   assert( pOp->p3>0 && pOp->p3<=p->nMem );
-  u.ci.pDest = &p->aMem[pOp->p3];
+  u.ch.pDest = &aMem[pOp->p3];
   if( pCur->nullRow ){
-    sqlite3VdbeMemSetNull(u.ci.pDest);
+    sqlite3VdbeMemSetNull(u.ch.pDest);
     break;
   }
-  u.ci.pVtab = pCur->pVtabCursor->pVtab;
-  u.ci.pModule = u.ci.pVtab->pModule;
-  assert( u.ci.pModule->xColumn );
-  memset(&u.ci.sContext, 0, sizeof(u.ci.sContext));
+  u.ch.pVtab = pCur->pVtabCursor->pVtab;
+  u.ch.pModule = u.ch.pVtab->pModule;
+  assert( u.ch.pModule->xColumn );
+  memset(&u.ch.sContext, 0, sizeof(u.ch.sContext));
 
   /* The output cell may already have a buffer allocated. Move
-  ** the current contents to u.ci.sContext.s so in case the user-function
+  ** the current contents to u.ch.sContext.s so in case the user-function
   ** can use the already allocated buffer instead of allocating a
   ** new one.
   */
-  sqlite3VdbeMemMove(&u.ci.sContext.s, u.ci.pDest);
-  MemSetTypeFlag(&u.ci.sContext.s, MEM_Null);
+  sqlite3VdbeMemMove(&u.ch.sContext.s, u.ch.pDest);
+  MemSetTypeFlag(&u.ch.sContext.s, MEM_Null);
 
   if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
-  rc = u.ci.pModule->xColumn(pCur->pVtabCursor, &u.ci.sContext, pOp->p2);
+  rc = u.ch.pModule->xColumn(pCur->pVtabCursor, &u.ch.sContext, pOp->p2);
   sqlite3DbFree(db, p->zErrMsg);
-  p->zErrMsg = u.ci.pVtab->zErrMsg;
-  u.ci.pVtab->zErrMsg = 0;
-  if( u.ci.sContext.isError ){
-    rc = u.ci.sContext.isError;
+  p->zErrMsg = u.ch.pVtab->zErrMsg;
+  u.ch.pVtab->zErrMsg = 0;
+  if( u.ch.sContext.isError ){
+    rc = u.ch.sContext.isError;
   }
 
   /* Copy the result of the function to the P3 register. We
   ** do this regardless of whether or not an error occurred to ensure any
-  ** dynamic allocation in u.ci.sContext.s (a Mem struct) is  released.
-  */
-  sqlite3VdbeChangeEncoding(&u.ci.sContext.s, encoding);
-  REGISTER_TRACE(pOp->p3, u.ci.pDest);
-  sqlite3VdbeMemMove(u.ci.pDest, &u.ci.sContext.s);
-  UPDATE_MAX_BLOBSIZE(u.ci.pDest);
+  ** dynamic allocation in u.ch.sContext.s (a Mem struct) is  released.
+  */
+  sqlite3VdbeChangeEncoding(&u.ch.sContext.s, encoding);
+  REGISTER_TRACE(pOp->p3, u.ch.pDest);
+  sqlite3VdbeMemMove(u.ch.pDest, &u.ch.sContext.s);
+  UPDATE_MAX_BLOBSIZE(u.ch.pDest);
 
   if( sqlite3SafetyOn(db) ){
     goto abort_due_to_misuse;
   }
-  if( sqlite3VdbeMemTooBig(u.ci.pDest) ){
+  if( sqlite3VdbeMemTooBig(u.ch.pDest) ){
     goto too_big;
   }
   break;
 }
 #endif /* SQLITE_OMIT_VIRTUALTABLE */
@@ -57551,46 +57538,46 @@
 ** Advance virtual table P1 to the next row in its result set and
 ** jump to instruction P2.  Or, if the virtual table has reached
 ** the end of its result set, then fall through to the next instruction.
 */
 case OP_VNext: {   /* jump */
-#if 0  /* local variables moved into u.cj */
+#if 0  /* local variables moved into u.ci */
   sqlite3_vtab *pVtab;
   const sqlite3_module *pModule;
   int res;
   VdbeCursor *pCur;
-#endif /* local variables moved into u.cj */
-
-  u.cj.res = 0;
-  u.cj.pCur = p->apCsr[pOp->p1];
-  assert( u.cj.pCur->pVtabCursor );
-  if( u.cj.pCur->nullRow ){
+#endif /* local variables moved into u.ci */
+
+  u.ci.res = 0;
+  u.ci.pCur = p->apCsr[pOp->p1];
+  assert( u.ci.pCur->pVtabCursor );
+  if( u.ci.pCur->nullRow ){
     break;
   }
-  u.cj.pVtab = u.cj.pCur->pVtabCursor->pVtab;
-  u.cj.pModule = u.cj.pVtab->pModule;
-  assert( u.cj.pModule->xNext );
+  u.ci.pVtab = u.ci.pCur->pVtabCursor->pVtab;
+  u.ci.pModule = u.ci.pVtab->pModule;
+  assert( u.ci.pModule->xNext );
 
   /* Invoke the xNext() method of the module. There is no way for the
   ** underlying implementation to return an error if one occurs during
   ** xNext(). Instead, if an error occurs, true is returned (indicating that
   ** data is available) and the error code returned when xColumn or
   ** some other method is next invoked on the save virtual table cursor.
   */
   if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
   p->inVtabMethod = 1;
-  rc = u.cj.pModule->xNext(u.cj.pCur->pVtabCursor);
+  rc = u.ci.pModule->xNext(u.ci.pCur->pVtabCursor);
   p->inVtabMethod = 0;
   sqlite3DbFree(db, p->zErrMsg);
-  p->zErrMsg = u.cj.pVtab->zErrMsg;
-  u.cj.pVtab->zErrMsg = 0;
-  if( rc==SQLITE_OK ){
-    u.cj.res = u.cj.pModule->xEof(u.cj.pCur->pVtabCursor);
+  p->zErrMsg = u.ci.pVtab->zErrMsg;
+  u.ci.pVtab->zErrMsg = 0;
+  if( rc==SQLITE_OK ){
+    u.ci.res = u.ci.pModule->xEof(u.ci.pCur->pVtabCursor);
   }
   if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
 
-  if( !u.cj.res ){
+  if( !u.ci.res ){
     /* If there is data, jump to P2 */
     pc = pOp->p2 - 1;
   }
   break;
 }
@@ -57602,25 +57589,25 @@
 ** P4 is a pointer to a virtual table object, an sqlite3_vtab structure.
 ** This opcode invokes the corresponding xRename method. The value
 ** in register P1 is passed as the zName argument to the xRename method.
 */
 case OP_VRename: {
-#if 0  /* local variables moved into u.ck */
+#if 0  /* local variables moved into u.cj */
   sqlite3_vtab *pVtab;
   Mem *pName;
-#endif /* local variables moved into u.ck */
-
-  u.ck.pVtab = pOp->p4.pVtab->pVtab;
-  u.ck.pName = &p->aMem[pOp->p1];
-  assert( u.ck.pVtab->pModule->xRename );
-  REGISTER_TRACE(pOp->p1, u.ck.pName);
-  assert( u.ck.pName->flags & MEM_Str );
+#endif /* local variables moved into u.cj */
+
+  u.cj.pVtab = pOp->p4.pVtab->pVtab;
+  u.cj.pName = &aMem[pOp->p1];
+  assert( u.cj.pVtab->pModule->xRename );
+  REGISTER_TRACE(pOp->p1, u.cj.pName);
+  assert( u.cj.pName->flags & MEM_Str );
   if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
-  rc = u.ck.pVtab->pModule->xRename(u.ck.pVtab, u.ck.pName->z);
+  rc = u.cj.pVtab->pModule->xRename(u.cj.pVtab, u.cj.pName->z);
   sqlite3DbFree(db, p->zErrMsg);
-  p->zErrMsg = u.ck.pVtab->zErrMsg;
-  u.ck.pVtab->zErrMsg = 0;
+  p->zErrMsg = u.cj.pVtab->zErrMsg;
+  u.cj.pVtab->zErrMsg = 0;
   if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
 
   break;
 }
 #endif
@@ -57648,41 +57635,41 @@
 ** P1 is a boolean flag. If it is set to true and the xUpdate call
 ** is successful, then the value returned by sqlite3_last_insert_rowid()
 ** is set to the value of the rowid for the row just inserted.
 */
 case OP_VUpdate: {
-#if 0  /* local variables moved into u.cl */
+#if 0  /* local variables moved into u.ck */
   sqlite3_vtab *pVtab;
   sqlite3_module *pModule;
   int nArg;
   int i;
   sqlite_int64 rowid;
   Mem **apArg;
   Mem *pX;
-#endif /* local variables moved into u.cl */
-
-  u.cl.pVtab = pOp->p4.pVtab->pVtab;
-  u.cl.pModule = (sqlite3_module *)u.cl.pVtab->pModule;
-  u.cl.nArg = pOp->p2;
+#endif /* local variables moved into u.ck */
+
+  u.ck.pVtab = pOp->p4.pVtab->pVtab;
+  u.ck.pModule = (sqlite3_module *)u.ck.pVtab->pModule;
+  u.ck.nArg = pOp->p2;
   assert( pOp->p4type==P4_VTAB );
-  if( ALWAYS(u.cl.pModule->xUpdate) ){
-    u.cl.apArg = p->apArg;
-    u.cl.pX = &p->aMem[pOp->p3];
-    for(u.cl.i=0; u.cl.i<u.cl.nArg; u.cl.i++){
-      sqlite3VdbeMemStoreType(u.cl.pX);
-      u.cl.apArg[u.cl.i] = u.cl.pX;
-      u.cl.pX++;
+  if( ALWAYS(u.ck.pModule->xUpdate) ){
+    u.ck.apArg = p->apArg;
+    u.ck.pX = &aMem[pOp->p3];
+    for(u.ck.i=0; u.ck.i<u.ck.nArg; u.ck.i++){
+      sqlite3VdbeMemStoreType(u.ck.pX);
+      u.ck.apArg[u.ck.i] = u.ck.pX;
+      u.ck.pX++;
     }
     if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
-    rc = u.cl.pModule->xUpdate(u.cl.pVtab, u.cl.nArg, u.cl.apArg, &u.cl.rowid);
+    rc = u.ck.pModule->xUpdate(u.ck.pVtab, u.ck.nArg, u.ck.apArg, &u.ck.rowid);
     sqlite3DbFree(db, p->zErrMsg);
-    p->zErrMsg = u.cl.pVtab->zErrMsg;
-    u.cl.pVtab->zErrMsg = 0;
+    p->zErrMsg = u.ck.pVtab->zErrMsg;
+    u.ck.pVtab->zErrMsg = 0;
     if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
     if( rc==SQLITE_OK && pOp->p1 ){
-      assert( u.cl.nArg>1 && u.cl.apArg[0] && (u.cl.apArg[0]->flags&MEM_Null) );
-      db->lastRowid = u.cl.rowid;
+      assert( u.ck.nArg>1 && u.ck.apArg[0] && (u.ck.apArg[0]->flags&MEM_Null) );
+      db->lastRowid = u.ck.rowid;
     }
     p->nChange++;
   }
   break;
 }
@@ -57692,25 +57679,24 @@
 /* Opcode: Pagecount P1 P2 * * *
 **
 ** Write the current number of pages in database P1 to memory cell P2.
 */
 case OP_Pagecount: {            /* out2-prerelease */
-#if 0  /* local variables moved into u.cm */
+#if 0  /* local variables moved into u.cl */
   int p1;
   int nPage;
   Pager *pPager;
-#endif /* local variables moved into u.cm */
-
-  u.cm.p1 = pOp->p1;
-  u.cm.pPager = sqlite3BtreePager(db->aDb[u.cm.p1].pBt);
-  rc = sqlite3PagerPagecount(u.cm.pPager, &u.cm.nPage);
+#endif /* local variables moved into u.cl */
+
+  u.cl.p1 = pOp->p1;
+  u.cl.pPager = sqlite3BtreePager(db->aDb[u.cl.p1].pBt);
+  rc = sqlite3PagerPagecount(u.cl.pPager, &u.cl.nPage);
   /* OP_Pagecount is always called from within a read transaction.  The
   ** page count has already been successfully read and cached.  So the
   ** sqlite3PagerPagecount() call above cannot fail. */
   if( ALWAYS(rc==SQLITE_OK) ){
-    pOut->flags = MEM_Int;
-    pOut->u.i = u.cm.nPage;
+    pOut->u.i = u.cl.nPage;
   }
   break;
 }
 #endif
 
@@ -57719,22 +57705,22 @@
 **
 ** If tracing is enabled (by the sqlite3_trace()) interface, then
 ** the UTF-8 string contained in P4 is emitted on the trace callback.
 */
 case OP_Trace: {
-#if 0  /* local variables moved into u.cn */
+#if 0  /* local variables moved into u.cm */
   char *zTrace;
-#endif /* local variables moved into u.cn */
-
-  u.cn.zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql);
-  if( u.cn.zTrace ){
+#endif /* local variables moved into u.cm */
+
+  u.cm.zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql);
+  if( u.cm.zTrace ){
     if( db->xTrace ){
-      db->xTrace(db->pTraceArg, u.cn.zTrace);
+      db->xTrace(db->pTraceArg, u.cm.zTrace);
     }
 #ifdef SQLITE_DEBUG
     if( (db->flags & SQLITE_SqlTrace)!=0 ){
-      sqlite3DebugPrintf("SQL-trace: %s\n", u.cn.zTrace);
+      sqlite3DebugPrintf("SQL-trace: %s\n", u.cm.zTrace);
     }
 #endif /* SQLITE_DEBUG */
   }
   break;
 }
@@ -57769,11 +57755,11 @@
       u64 elapsed = sqlite3Hwtime() - start;
       pOp->cycles += elapsed;
       pOp->cnt++;
 #if 0
         fprintf(stdout, "%10llu ", elapsed);
-        sqlite3VdbePrintOp(stdout, origPc, &p->aOp[origPc]);
+        sqlite3VdbePrintOp(stdout, origPc, &aOp[origPc]);
 #endif
     }
 #endif
 
     /* The following code adds nothing to the actual functionality
@@ -57785,15 +57771,15 @@
     assert( pc>=-1 && pc<p->nOp );
 
 #ifdef SQLITE_DEBUG
     if( p->trace ){
       if( rc!=0 ) fprintf(p->trace,"rc=%d\n",rc);
-      if( opProperty & OPFLG_OUT2_PRERELEASE ){
-        registerTrace(p->trace, pOp->p2, pOut);
-      }
-      if( opProperty & OPFLG_OUT3 ){
-        registerTrace(p->trace, pOp->p3, pOut);
+      if( pOp->opflags & (OPFLG_OUT2_PRERELEASE|OPFLG_OUT2) ){
+        registerTrace(p->trace, pOp->p2, &aMem[pOp->p2]);
+      }
+      if( pOp->opflags & OPFLG_OUT3 ){
+        registerTrace(p->trace, pOp->p3, &aMem[pOp->p3]);
       }
     }
 #endif  /* SQLITE_DEBUG */
 #endif  /* NDEBUG */
   }  /* The end of the for(;;) loop the loops through opcodes */
@@ -57805,10 +57791,11 @@
   assert( rc );
   p->rc = rc;
   sqlite3VdbeHalt(p);
   if( rc==SQLITE_IOERR_NOMEM ) db->mallocFailed = 1;
   rc = SQLITE_ERROR;
+  if( resetSchemaOnFault ) sqlite3ResetInternalSchema(db, 0);
 
   /* This is the only way out of this procedure.  We have to
   ** release the mutexes on btrees that were acquired at the
   ** top. */
 vdbe_return:
@@ -57872,12 +57859,10 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 **
 ** This file contains code used to implement incremental BLOB I/O.
-**
-** $Id: vdbeblob.c,v 1.35 2009/07/02 07:47:33 danielk1977 Exp $
 */
 
 
 #ifndef SQLITE_OMIT_INCRBLOB
 
@@ -58266,16 +58251,10 @@
 **    May you find forgiveness for yourself and forgive others.
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 **
-** @(#) $Id: journal.c,v 1.9 2009/01/20 17:06:27 danielk1977 Exp $
-*/
-
-#ifdef SQLITE_ENABLE_ATOMIC_WRITE
-
-/*
 ** This file implements a special kind of sqlite3_file object used
 ** by SQLite to create journal files if the atomic-write optimization
 ** is enabled.
 **
 ** The distinctive characteristic of this sqlite3_file is that the
@@ -58286,11 +58265,11 @@
 **
 **   1) The in-memory representation grows too large for the allocated
 **      buffer, or
 **   2) The sqlite3JournalCreate() function is called.
 */
-
+#ifdef SQLITE_ENABLE_ATOMIC_WRITE
 
 
 /*
 ** A JournalFile object is a subclass of sqlite3_file used by
 ** as an open file handle for journal files.
@@ -58511,12 +58490,10 @@
 *************************************************************************
 **
 ** This file contains code use to implement an in-memory rollback journal.
 ** The in-memory rollback journal is used to journal transactions for
 ** ":memory:" databases and when the journal_mode=MEMORY pragma is used.
-**
-** @(#) $Id: memjournal.c,v 1.12 2009/05/04 11:42:30 danielk1977 Exp $
 */
 
 /* Forward references to internal structures */
 typedef struct MemJournal MemJournal;
 typedef struct FilePoint FilePoint;
@@ -58770,12 +58747,10 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 ** This file contains routines used for walking the parser tree for
 ** an SQL statement.
-**
-** $Id: walker.c,v 1.7 2009/06/15 23:15:59 drh Exp $
 */
 
 
 /*
 ** Walk an expression tree.  Invoke the callback once for each node
@@ -58910,12 +58885,10 @@
 *************************************************************************
 **
 ** This file contains routines used for walking the parser tree and
 ** resolve all identifiers by associating them with a particular
 ** table and column.
-**
-** $Id: resolve.c,v 1.30 2009/06/15 23:15:59 drh Exp $
 */
 
 /*
 ** Turn the pExpr expression into an alias for the iCol-th column of the
 ** result set in pEList.
@@ -61344,10 +61317,98 @@
   }
   return rc;
 }
 
 /*
+** Return FALSE if there is no chance that the expression can be NULL.
+**
+** If the expression might be NULL or if the expression is too complex
+** to tell return TRUE.
+**
+** This routine is used as an optimization, to skip OP_IsNull opcodes
+** when we know that a value cannot be NULL.  Hence, a false positive
+** (returning TRUE when in fact the expression can never be NULL) might
+** be a small performance hit but is otherwise harmless.  On the other
+** hand, a false negative (returning FALSE when the result could be NULL)
+** will likely result in an incorrect answer.  So when in doubt, return
+** TRUE.
+*/
+SQLITE_PRIVATE int sqlite3ExprCanBeNull(const Expr *p){
+  u8 op;
+  while( p->op==TK_UPLUS || p->op==TK_UMINUS ){ p = p->pLeft; }
+  op = p->op;
+  if( op==TK_REGISTER ) op = p->op2;
+  switch( op ){
+    case TK_INTEGER:
+    case TK_STRING:
+    case TK_FLOAT:
+    case TK_BLOB:
+      return 0;
+    default:
+      return 1;
+  }
+}
+
+/*
+** Generate an OP_IsNull instruction that tests register iReg and jumps
+** to location iDest if the value in iReg is NULL.  The value in iReg
+** was computed by pExpr.  If we can look at pExpr at compile-time and
+** determine that it can never generate a NULL, then the OP_IsNull operation
+** can be omitted.
+*/
+SQLITE_PRIVATE void sqlite3ExprCodeIsNullJump(
+  Vdbe *v,            /* The VDBE under construction */
+  const Expr *pExpr,  /* Only generate OP_IsNull if this expr can be NULL */
+  int iReg,           /* Test the value in this register for NULL */
+  int iDest           /* Jump here if the value is null */
+){
+  if( sqlite3ExprCanBeNull(pExpr) ){
+    sqlite3VdbeAddOp2(v, OP_IsNull, iReg, iDest);
+  }
+}
+
+/*
+** Return TRUE if the given expression is a constant which would be
+** unchanged by OP_Affinity with the affinity given in the second
+** argument.
+**
+** This routine is used to determine if the OP_Affinity operation
+** can be omitted.  When in doubt return FALSE.  A false negative
+** is harmless.  A false positive, however, can result in the wrong
+** answer.
+*/
+SQLITE_PRIVATE int sqlite3ExprNeedsNoAffinityChange(const Expr *p, char aff){
+  u8 op;
+  if( aff==SQLITE_AFF_NONE ) return 1;
+  while( p->op==TK_UPLUS || p->op==TK_UMINUS ){ p = p->pLeft; }
+  op = p->op;
+  if( op==TK_REGISTER ) op = p->op2;
+  switch( op ){
+    case TK_INTEGER: {
+      return aff==SQLITE_AFF_INTEGER || aff==SQLITE_AFF_NUMERIC;
+    }
+    case TK_FLOAT: {
+      return aff==SQLITE_AFF_REAL || aff==SQLITE_AFF_NUMERIC;
+    }
+    case TK_STRING: {
+      return aff==SQLITE_AFF_TEXT;
+    }
+    case TK_BLOB: {
+      return 1;
+    }
+    case TK_COLUMN: {
+      assert( p->iTable>=0 );  /* p cannot be part of a CHECK constraint */
+      return p->iColumn<0
+          && (aff==SQLITE_AFF_INTEGER || aff==SQLITE_AFF_NUMERIC);
+    }
+    default: {
+      return 0;
+    }
+  }
+}
+
+/*
 ** Return TRUE if the given string is a row-id column name.
 */
 SQLITE_PRIVATE int sqlite3IsRowid(const char *z){
   if( sqlite3StrICmp(z, "_ROWID_")==0 ) return 1;
   if( sqlite3StrICmp(z, "ROWID")==0 ) return 1;
@@ -61430,20 +61491,20 @@
 ** be found with <column> as its left-most column.
 **
 ** When the b-tree is being used for membership tests, the calling function
 ** needs to know whether or not the structure contains an SQL NULL
 ** value in order to correctly evaluate expressions like "X IN (Y, Z)".
-** If there is a chance that the b-tree might contain a NULL value at
+** If there is any chance that the (...) might contain a NULL value at
 ** runtime, then a register is allocated and the register number written
-** to *prNotFound. If there is no chance that the b-tree contains a
+** to *prNotFound. If there is no chance that the (...) contains a
 ** NULL value, then *prNotFound is left unchanged.
 **
 ** If a register is allocated and its location stored in *prNotFound, then
-** its initial value is NULL. If the b-tree does not remain constant
-** for the duration of the query (i.e. the SELECT that generates the b-tree
+** its initial value is NULL.  If the (...) does not remain constant
+** for the duration of the query (i.e. the SELECT within the (...)
 ** is a correlated subquery) then the value of the allocated register is
-** reset to NULL each time the b-tree is repopulated. This allows the
+** reset to NULL each time the subquery is rerun. This allows the
 ** caller to use vdbe code equivalent to the following:
 **
 **   if( register==NULL ){
 **     has_null = <test if data structure contains null>
 **     register = 1
@@ -61631,11 +61692,11 @@
       }
 
       affinity = sqlite3ExprAffinity(pLeft);
 
       /* Whether this is an 'x IN(SELECT...)' or an 'x IN(<exprlist>)'
-      ** expression it is handled the same way. A virtual table is
+      ** expression it is handled the same way.  An ephemeral table is
       ** filled with single-field index keys representing the results
       ** from the SELECT or the <exprlist>.
       **
       ** If the 'x' expression is a column value, or the SELECT...
       ** statement returns a column value, then the affinity of that
@@ -61776,10 +61837,132 @@
     sqlite3VdbeJumpHere(v, testAddr-1);
   }
   sqlite3ExprCachePop(pParse, 1);
 
   return rReg;
+}
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Generate code for an IN expression.
+**
+**      x IN (SELECT ...)
+**      x IN (value, value, ...)
+**
+** The left-hand side (LHS) is a scalar expression.  The right-hand side (RHS)
+** is an array of zero or more values.  The expression is true if the LHS is
+** contained within the RHS.  The value of the expression is unknown (NULL)
+** if the LHS is NULL or if the LHS is not contained within the RHS and the
+** RHS contains one or more NULL values.
+**
+** This routine generates code will jump to destIfFalse if the LHS is not
+** contained within the RHS.  If due to NULLs we cannot determine if the LHS
+** is contained in the RHS then jump to destIfNull.  If the LHS is contained
+** within the RHS then fall through.
+*/
+static void sqlite3ExprCodeIN(
+  Parse *pParse,        /* Parsing and code generating context */
+  Expr *pExpr,          /* The IN expression */
+  int destIfFalse,      /* Jump here if LHS is not contained in the RHS */
+  int destIfNull        /* Jump here if the results are unknown due to NULLs */
+){
+  int rRhsHasNull = 0;  /* Register that is true if RHS contains NULL values */
+  char affinity;        /* Comparison affinity to use */
+  int eType;            /* Type of the RHS */
+  int r1;               /* Temporary use register */
+  Vdbe *v;              /* Statement under construction */
+
+  /* Compute the RHS.   After this step, the table with cursor
+  ** pExpr->iTable will contains the values that make up the RHS.
+  */
+  v = pParse->pVdbe;
+  assert( v!=0 );       /* OOM detected prior to this routine */
+  VdbeNoopComment((v, "begin IN expr"));
+  eType = sqlite3FindInIndex(pParse, pExpr, &rRhsHasNull);
+
+  /* Figure out the affinity to use to create a key from the results
+  ** of the expression. affinityStr stores a static string suitable for
+  ** P4 of OP_MakeRecord.
+  */
+  affinity = comparisonAffinity(pExpr);
+
+  /* Code the LHS, the <expr> from "<expr> IN (...)".
+  */
+  sqlite3ExprCachePush(pParse);
+  r1 = sqlite3GetTempReg(pParse);
+  sqlite3ExprCode(pParse, pExpr->pLeft, r1);
+  sqlite3VdbeAddOp2(v, OP_IsNull, r1, destIfNull);
+
+
+  if( eType==IN_INDEX_ROWID ){
+    /* In this case, the RHS is the ROWID of table b-tree
+    */
+    sqlite3VdbeAddOp2(v, OP_MustBeInt, r1, destIfFalse);
+    sqlite3VdbeAddOp3(v, OP_NotExists, pExpr->iTable, destIfFalse, r1);
+  }else{
+    /* In this case, the RHS is an index b-tree.
+    */
+    sqlite3VdbeAddOp4(v, OP_Affinity, r1, 1, 0, &affinity, 1);
+
+    /* If the set membership test fails, then the result of the
+    ** "x IN (...)" expression must be either 0 or NULL. If the set
+    ** contains no NULL values, then the result is 0. If the set
+    ** contains one or more NULL values, then the result of the
+    ** expression is also NULL.
+    */
+    if( rRhsHasNull==0 || destIfFalse==destIfNull ){
+      /* This branch runs if it is known at compile time that the RHS
+      ** cannot contain NULL values. This happens as the result
+      ** of a "NOT NULL" constraint in the database schema.
+      **
+      ** Also run this branch if NULL is equivalent to FALSE
+      ** for this particular IN operator.
+      */
+      sqlite3VdbeAddOp4Int(v, OP_NotFound, pExpr->iTable, destIfFalse, r1, 1);
+
+    }else{
+      /* In this branch, the RHS of the IN might contain a NULL and
+      ** the presence of a NULL on the RHS makes a difference in the
+      ** outcome.
+      */
+      int j1, j2, j3;
+
+      /* First check to see if the LHS is contained in the RHS.  If so,
+      ** then the presence of NULLs in the RHS does not matter, so jump
+      ** over all of the code that follows.
+      */
+      j1 = sqlite3VdbeAddOp4Int(v, OP_Found, pExpr->iTable, 0, r1, 1);
+
+      /* Here we begin generating code that runs if the LHS is not
+      ** contained within the RHS.  Generate additional code that
+      ** tests the RHS for NULLs.  If the RHS contains a NULL then
+      ** jump to destIfNull.  If there are no NULLs in the RHS then
+      ** jump to destIfFalse.
+      */
+      j2 = sqlite3VdbeAddOp1(v, OP_NotNull, rRhsHasNull);
+      j3 = sqlite3VdbeAddOp4Int(v, OP_Found, pExpr->iTable, 0, rRhsHasNull, 1);
+      sqlite3VdbeAddOp2(v, OP_Integer, -1, rRhsHasNull);
+      sqlite3VdbeJumpHere(v, j3);
+      sqlite3VdbeAddOp2(v, OP_AddImm, rRhsHasNull, 1);
+      sqlite3VdbeJumpHere(v, j2);
+
+      /* Jump to the appropriate target depending on whether or not
+      ** the RHS contains a NULL
+      */
+      sqlite3VdbeAddOp2(v, OP_If, rRhsHasNull, destIfNull);
+      sqlite3VdbeAddOp2(v, OP_Goto, 0, destIfFalse);
+
+      /* The OP_Found at the top of this branch jumps here when true,
+      ** causing the overall IN expression evaluation to fall through.
+      */
+      sqlite3VdbeJumpHere(v, j1);
+    }
+  }
+  sqlite3ReleaseTempReg(pParse, r1);
+  sqlite3ExprCachePop(pParse, 1);
+  VdbeComment((v, "end IN expr"));
 }
 #endif /* SQLITE_OMIT_SUBQUERY */
 
 /*
 ** Duplicate an 8-byte value
@@ -62479,10 +62662,31 @@
       pDef = sqlite3FindFunction(db, zId, nId, nFarg, enc, 0);
       if( pDef==0 ){
         sqlite3ErrorMsg(pParse, "unknown function: %.*s()", nId, zId);
         break;
       }
+
+      /* Attempt a direct implementation of the built-in COALESCE() and
+      ** IFNULL() functions.  This avoids unnecessary evalation of
+      ** arguments past the first non-NULL argument.
+      */
+      if( pDef->flags & SQLITE_FUNC_COALESCE ){
+        int endCoalesce = sqlite3VdbeMakeLabel(v);
+        assert( nFarg>=2 );
+        sqlite3ExprCode(pParse, pFarg->a[0].pExpr, target);
+        for(i=1; i<nFarg; i++){
+          sqlite3VdbeAddOp2(v, OP_NotNull, target, endCoalesce);
+          sqlite3ExprCacheRemove(pParse, target);
+          sqlite3ExprCachePush(pParse);
+          sqlite3ExprCode(pParse, pFarg->a[i].pExpr, target);
+          sqlite3ExprCachePop(pParse, 1);
+        }
+        sqlite3VdbeResolveLabel(v, endCoalesce);
+        break;
+      }
+
+
       if( pFarg ){
         r1 = sqlite3GetTempRange(pParse, nFarg);
         sqlite3ExprCachePush(pParse);     /* Ticket 2ea2425d34be */
         sqlite3ExprCodeExprList(pParse, pFarg, r1, 1);
         sqlite3ExprCachePop(pParse, 1);   /* Ticket 2ea2425d34be */
@@ -62536,99 +62740,23 @@
       testcase( op==TK_SELECT );
       inReg = sqlite3CodeSubselect(pParse, pExpr, 0, 0);
       break;
     }
     case TK_IN: {
-      int rNotFound = 0;
-      int rMayHaveNull = 0;
-      int j2, j3, j4, j5;
-      char affinity;
-      int eType;
-
-      VdbeNoopComment((v, "begin IN expr r%d", target));
-      eType = sqlite3FindInIndex(pParse, pExpr, &rMayHaveNull);
-      if( rMayHaveNull ){
-        rNotFound = ++pParse->nMem;
-      }
-
-      /* Figure out the affinity to use to create a key from the results
-      ** of the expression. affinityStr stores a static string suitable for
-      ** P4 of OP_MakeRecord.
-      */
-      affinity = comparisonAffinity(pExpr);
-
-
-      /* Code the <expr> from "<expr> IN (...)". The temporary table
-      ** pExpr->iTable contains the values that make up the (...) set.
-      */
-      sqlite3ExprCachePush(pParse);
-      sqlite3ExprCode(pParse, pExpr->pLeft, target);
-      j2 = sqlite3VdbeAddOp1(v, OP_IsNull, target);
-      if( eType==IN_INDEX_ROWID ){
-        j3 = sqlite3VdbeAddOp1(v, OP_MustBeInt, target);
-        j4 = sqlite3VdbeAddOp3(v, OP_NotExists, pExpr->iTable, 0, target);
-        sqlite3VdbeAddOp2(v, OP_Integer, 1, target);
-        j5 = sqlite3VdbeAddOp0(v, OP_Goto);
-        sqlite3VdbeJumpHere(v, j3);
-        sqlite3VdbeJumpHere(v, j4);
-        sqlite3VdbeAddOp2(v, OP_Integer, 0, target);
-      }else{
-        r2 = regFree2 = sqlite3GetTempReg(pParse);
-
-        /* Create a record and test for set membership. If the set contains
-        ** the value, then jump to the end of the test code. The target
-        ** register still contains the true (1) value written to it earlier.
-        */
-        sqlite3VdbeAddOp4(v, OP_MakeRecord, target, 1, r2, &affinity, 1);
-        sqlite3VdbeAddOp2(v, OP_Integer, 1, target);
-        j5 = sqlite3VdbeAddOp3(v, OP_Found, pExpr->iTable, 0, r2);
-
-        /* If the set membership test fails, then the result of the
-        ** "x IN (...)" expression must be either 0 or NULL. If the set
-        ** contains no NULL values, then the result is 0. If the set
-        ** contains one or more NULL values, then the result of the
-        ** expression is also NULL.
-        */
-        if( rNotFound==0 ){
-          /* This branch runs if it is known at compile time (now) that
-          ** the set contains no NULL values. This happens as the result
-          ** of a "NOT NULL" constraint in the database schema. No need
-          ** to test the data structure at runtime in this case.
-          */
-          sqlite3VdbeAddOp2(v, OP_Integer, 0, target);
-        }else{
-          /* This block populates the rNotFound register with either NULL
-          ** or 0 (an integer value). If the data structure contains one
-          ** or more NULLs, then set rNotFound to NULL. Otherwise, set it
-          ** to 0. If register rMayHaveNull is already set to some value
-          ** other than NULL, then the test has already been run and
-          ** rNotFound is already populated.
-          */
-          static const char nullRecord[] = { 0x02, 0x00 };
-          j3 = sqlite3VdbeAddOp1(v, OP_NotNull, rMayHaveNull);
-          sqlite3VdbeAddOp2(v, OP_Null, 0, rNotFound);
-          sqlite3VdbeAddOp4(v, OP_Blob, 2, rMayHaveNull, 0,
-                             nullRecord, P4_STATIC);
-          j4 = sqlite3VdbeAddOp3(v, OP_Found, pExpr->iTable, 0, rMayHaveNull);
-          sqlite3VdbeAddOp2(v, OP_Integer, 0, rNotFound);
-          sqlite3VdbeJumpHere(v, j4);
-          sqlite3VdbeJumpHere(v, j3);
-
-          /* Copy the value of register rNotFound (which is either NULL or 0)
-          ** into the target register. This will be the result of the
-          ** expression.
-          */
-          sqlite3VdbeAddOp2(v, OP_Copy, rNotFound, target);
-        }
-      }
-      sqlite3VdbeJumpHere(v, j2);
-      sqlite3VdbeJumpHere(v, j5);
-      sqlite3ExprCachePop(pParse, 1);
-      VdbeComment((v, "end IN expr r%d", target));
-      break;
-    }
-#endif
+      int destIfFalse = sqlite3VdbeMakeLabel(v);
+      int destIfNull = sqlite3VdbeMakeLabel(v);
+      sqlite3VdbeAddOp2(v, OP_Null, 0, target);
+      sqlite3ExprCodeIN(pParse, pExpr, destIfFalse, destIfNull);
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, target);
+      sqlite3VdbeResolveLabel(v, destIfFalse);
+      sqlite3VdbeAddOp2(v, OP_AddImm, target, 0);
+      sqlite3VdbeResolveLabel(v, destIfNull);
+      break;
+    }
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+
     /*
     **    x BETWEEN y AND z
     **
     ** This is equivalent to
     **
@@ -63056,10 +63184,66 @@
   }
   return n;
 }
 
 /*
+** Generate code for a BETWEEN operator.
+**
+**    x BETWEEN y AND z
+**
+** The above is equivalent to
+**
+**    x>=y AND x<=z
+**
+** Code it as such, taking care to do the common subexpression
+** elementation of x.
+*/
+static void exprCodeBetween(
+  Parse *pParse,    /* Parsing and code generating context */
+  Expr *pExpr,      /* The BETWEEN expression */
+  int dest,         /* Jump here if the jump is taken */
+  int jumpIfTrue,   /* Take the jump if the BETWEEN is true */
+  int jumpIfNull    /* Take the jump if the BETWEEN is NULL */
+){
+  Expr exprAnd;     /* The AND operator in  x>=y AND x<=z  */
+  Expr compLeft;    /* The  x>=y  term */
+  Expr compRight;   /* The  x<=z  term */
+  Expr exprX;       /* The  x  subexpression */
+  int regFree1 = 0; /* Temporary use register */
+
+  assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
+  exprX = *pExpr->pLeft;
+  exprAnd.op = TK_AND;
+  exprAnd.pLeft = &compLeft;
+  exprAnd.pRight = &compRight;
+  compLeft.op = TK_GE;
+  compLeft.pLeft = &exprX;
+  compLeft.pRight = pExpr->x.pList->a[0].pExpr;
+  compRight.op = TK_LE;
+  compRight.pLeft = &exprX;
+  compRight.pRight = pExpr->x.pList->a[1].pExpr;
+  exprX.iTable = sqlite3ExprCodeTemp(pParse, &exprX, &regFree1);
+  exprX.op = TK_REGISTER;
+  if( jumpIfTrue ){
+    sqlite3ExprIfTrue(pParse, &exprAnd, dest, jumpIfNull);
+  }else{
+    sqlite3ExprIfFalse(pParse, &exprAnd, dest, jumpIfNull);
+  }
+  sqlite3ReleaseTempReg(pParse, regFree1);
+
+  /* Ensure adequate test coverage */
+  testcase( jumpIfTrue==0 && jumpIfNull==0 && regFree1==0 );
+  testcase( jumpIfTrue==0 && jumpIfNull==0 && regFree1!=0 );
+  testcase( jumpIfTrue==0 && jumpIfNull!=0 && regFree1==0 );
+  testcase( jumpIfTrue==0 && jumpIfNull!=0 && regFree1!=0 );
+  testcase( jumpIfTrue!=0 && jumpIfNull==0 && regFree1==0 );
+  testcase( jumpIfTrue!=0 && jumpIfNull==0 && regFree1!=0 );
+  testcase( jumpIfTrue!=0 && jumpIfNull!=0 && regFree1==0 );
+  testcase( jumpIfTrue!=0 && jumpIfNull!=0 && regFree1!=0 );
+}
+
+/*
 ** Generate code for a boolean expression such that a jump is made
 ** to the label "dest" if the expression is true but execution
 ** continues straight thru if the expression is false.
 **
 ** If the expression evaluates to NULL (neither true nor false), then
@@ -63154,40 +63338,20 @@
       sqlite3VdbeAddOp2(v, op, r1, dest);
       testcase( regFree1==0 );
       break;
     }
     case TK_BETWEEN: {
-      /*    x BETWEEN y AND z
-      **
-      ** Is equivalent to
-      **
-      **    x>=y AND x<=z
-      **
-      ** Code it as such, taking care to do the common subexpression
-      ** elementation of x.
-      */
-      Expr exprAnd;
-      Expr compLeft;
-      Expr compRight;
-      Expr exprX;
-
-      assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
-      exprX = *pExpr->pLeft;
-      exprAnd.op = TK_AND;
-      exprAnd.pLeft = &compLeft;
-      exprAnd.pRight = &compRight;
-      compLeft.op = TK_GE;
-      compLeft.pLeft = &exprX;
-      compLeft.pRight = pExpr->x.pList->a[0].pExpr;
-      compRight.op = TK_LE;
-      compRight.pLeft = &exprX;
-      compRight.pRight = pExpr->x.pList->a[1].pExpr;
-      exprX.iTable = sqlite3ExprCodeTemp(pParse, &exprX, &regFree1);
-      testcase( regFree1==0 );
-      exprX.op = TK_REGISTER;
       testcase( jumpIfNull==0 );
-      sqlite3ExprIfTrue(pParse, &exprAnd, dest, jumpIfNull);
+      exprCodeBetween(pParse, pExpr, dest, 1, jumpIfNull);
+      break;
+    }
+    case TK_IN: {
+      int destIfFalse = sqlite3VdbeMakeLabel(v);
+      int destIfNull = jumpIfNull ? dest : destIfFalse;
+      sqlite3ExprCodeIN(pParse, pExpr, destIfFalse, destIfNull);
+      sqlite3VdbeAddOp2(v, OP_Goto, 0, dest);
+      sqlite3VdbeResolveLabel(v, destIfFalse);
       break;
     }
     default: {
       r1 = sqlite3ExprCodeTemp(pParse, pExpr, &regFree1);
       sqlite3VdbeAddOp3(v, OP_If, r1, dest, jumpIfNull!=0);
@@ -63267,10 +63431,11 @@
       sqlite3VdbeResolveLabel(v, d2);
       sqlite3ExprCachePop(pParse, 1);
       break;
     }
     case TK_NOT: {
+      testcase( jumpIfNull==0 );
       sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest, jumpIfNull);
       break;
     }
     case TK_LT:
     case TK_LE:
@@ -63314,40 +63479,22 @@
       sqlite3VdbeAddOp2(v, op, r1, dest);
       testcase( regFree1==0 );
       break;
     }
     case TK_BETWEEN: {
-      /*    x BETWEEN y AND z
-      **
-      ** Is equivalent to
-      **
-      **    x>=y AND x<=z
-      **
-      ** Code it as such, taking care to do the common subexpression
-      ** elementation of x.
-      */
-      Expr exprAnd;
-      Expr compLeft;
-      Expr compRight;
-      Expr exprX;
-
-      assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
-      exprX = *pExpr->pLeft;
-      exprAnd.op = TK_AND;
-      exprAnd.pLeft = &compLeft;
-      exprAnd.pRight = &compRight;
-      compLeft.op = TK_GE;
-      compLeft.pLeft = &exprX;
-      compLeft.pRight = pExpr->x.pList->a[0].pExpr;
-      compRight.op = TK_LE;
-      compRight.pLeft = &exprX;
-      compRight.pRight = pExpr->x.pList->a[1].pExpr;
-      exprX.iTable = sqlite3ExprCodeTemp(pParse, &exprX, &regFree1);
-      testcase( regFree1==0 );
-      exprX.op = TK_REGISTER;
       testcase( jumpIfNull==0 );
-      sqlite3ExprIfFalse(pParse, &exprAnd, dest, jumpIfNull);
+      exprCodeBetween(pParse, pExpr, dest, 0, jumpIfNull);
+      break;
+    }
+    case TK_IN: {
+      if( jumpIfNull ){
+        sqlite3ExprCodeIN(pParse, pExpr, dest, dest);
+      }else{
+        int destIfNull = sqlite3VdbeMakeLabel(v);
+        sqlite3ExprCodeIN(pParse, pExpr, dest, destIfNull);
+        sqlite3VdbeResolveLabel(v, destIfNull);
+      }
       break;
     }
     default: {
       r1 = sqlite3ExprCodeTemp(pParse, pExpr, &regFree1);
       sqlite3VdbeAddOp3(v, OP_IfNot, r1, dest, jumpIfNull!=0);
@@ -63692,12 +63839,10 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 ** This file contains C code routines that used to generate VDBE code
 ** that implements the ALTER TABLE command.
-**
-** $Id: alter.c,v 1.62 2009/07/24 17:58:53 danielk1977 Exp $
 */
 
 /*
 ** The code in this file only exists if we are not omitting the
 ** ALTER TABLE logic from the build.
@@ -64488,12 +64633,10 @@
 **    May you find forgiveness for yourself and forgive others.
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 ** This file contains code associated with the ANALYZE command.
-**
-** @(#) $Id: analyze.c,v 1.52 2009/04/16 17:45:48 drh Exp $
 */
 #ifndef SQLITE_OMIT_ANALYZE
 
 /*
 ** This routine generates code that opens the sqlite_stat1 table for
@@ -65143,12 +65286,10 @@
 **    May you find forgiveness for yourself and forgive others.
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 ** This file contains code used to implement the ATTACH and DETACH commands.
-**
-** $Id: attach.c,v 1.93 2009/05/31 21:21:41 drh Exp $
 */
 
 #ifndef SQLITE_OMIT_ATTACH
 /*
 ** Resolve an expression that was part of an ATTACH or DETACH statement. This
@@ -65685,12 +65826,10 @@
 *************************************************************************
 ** This file contains code used to implement the sqlite3_set_authorizer()
 ** API.  This facility is an optional feature of the library.  Embedded
 ** systems that do not need this facility may omit it by recompiling
 ** the library with -DSQLITE_OMIT_AUTHORIZATION=1
-**
-** $Id: auth.c,v 1.32 2009/07/02 18:40:35 danielk1977 Exp $
 */
 
 /*
 ** All of the code in this file may be omitted by defining a single
 ** macro.
@@ -65946,12 +66085,10 @@
 **     DROP INDEX
 **     creating ID lists
 **     BEGIN TRANSACTION
 **     COMMIT
 **     ROLLBACK
-**
-** $Id: build.c,v 1.557 2009/07/24 17:58:53 danielk1977 Exp $
 */
 
 /*
 ** This routine is called when a new SQL statement is beginning to
 ** be parsed.  Initialize the pParse structure as needed.
@@ -69645,12 +69782,10 @@
 **
 *************************************************************************
 **
 ** This file contains functions used to access the internal hash tables
 ** of user defined functions and collation sequences.
-**
-** $Id: callback.c,v 1.42 2009/06/17 00:35:31 drh Exp $
 */
 
 
 /*
 ** Invoke the 'collation needed' callback to request a collation sequence
@@ -70098,12 +70233,10 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 ** This file contains C code routines that are called by the parser
 ** in order to generate code for DELETE FROM statements.
-**
-** $Id: delete.c,v 1.207 2009/08/08 18:01:08 drh Exp $
 */
 
 /*
 ** Look up every table that is named in pSrc.  If any table is not found,
 ** add an error message to pParse->zErrMsg and return NULL.  If all tables
@@ -70722,11 +70855,10 @@
   }
   sqlite3ReleaseTempRange(pParse, regBase, nCol+1);
   return regBase;
 }
 
-
 /************** End of delete.c **********************************************/
 /************** Begin file func.c ********************************************/
 /*
 ** 2002 February 23
 **
@@ -70880,10 +71012,12 @@
 ** p1 is 1-indexed.  So substr(x,1,1) returns the first character
 ** of x.  If x is text, then we actually count UTF-8 characters.
 ** If x is a blob, then we count bytes.
 **
 ** If p1 is negative, then we begin abs(p1) from the end of x[].
+**
+** If p2 is negative, return the p2 characters preceeding p1.
 */
 static void substrFunc(
   sqlite3_context *context,
   int argc,
   sqlite3_value **argv
@@ -70900,24 +71034,26 @@
    || (argc==3 && sqlite3_value_type(argv[2])==SQLITE_NULL)
   ){
     return;
   }
   p0type = sqlite3_value_type(argv[0]);
+  p1 = sqlite3_value_int(argv[1]);
   if( p0type==SQLITE_BLOB ){
     len = sqlite3_value_bytes(argv[0]);
     z = sqlite3_value_blob(argv[0]);
     if( z==0 ) return;
     assert( len==sqlite3_value_bytes(argv[0]) );
   }else{
     z = sqlite3_value_text(argv[0]);
     if( z==0 ) return;
     len = 0;
-    for(z2=z; *z2; len++){
-      SQLITE_SKIP_UTF8(z2);
-    }
-  }
-  p1 = sqlite3_value_int(argv[1]);
+    if( p1<0 ){
+      for(z2=z; *z2; len++){
+        SQLITE_SKIP_UTF8(z2);
+      }
+    }
+  }
   if( argc==3 ){
     p2 = sqlite3_value_int(argv[2]);
     if( p2<0 ){
       p2 = -p2;
       negP2 = 1;
@@ -70943,14 +71079,10 @@
       p2 += p1;
       p1 = 0;
     }
   }
   assert( p1>=0 && p2>=0 );
-  if( p1+p2>len ){
-    p2 = len-p1;
-    if( p2<0 ) p2 = 0;
-  }
   if( p0type!=SQLITE_BLOB ){
     while( *z && p1 ){
       SQLITE_SKIP_UTF8(z);
       p1--;
     }
@@ -70957,10 +71089,14 @@
     for(z2=z; *z2 && p2; p2--){
       SQLITE_SKIP_UTF8(z2);
     }
     sqlite3_result_text(context, (char*)z, (int)(z2-z), SQLITE_TRANSIENT);
   }else{
+    if( p1+p2>len ){
+      p2 = len-p1;
+      if( p2<0 ) p2 = 0;
+    }
     sqlite3_result_blob(context, (char*)&z[p1], (int)p2, SQLITE_TRANSIENT);
   }
 }
 
 /*
@@ -71058,10 +71194,18 @@
       sqlite3_result_text(context, (char *)z1, -1, sqlite3_free);
     }
   }
 }
 
+
+#if 0  /* This function is never used. */
+/*
+** The COALESCE() and IFNULL() functions used to be implemented as shown
+** here.  But now they are implemented as VDBE code so that unused arguments
+** do not have to be computed.  This legacy implementation is retained as
+** comment.
+*/
 /*
 ** Implementation of the IFNULL(), NVL(), and COALESCE() functions.
 ** All three do the same thing.  They return the first non-NULL
 ** argument.
 */
@@ -71076,10 +71220,12 @@
       sqlite3_result_value(context, argv[i]);
       break;
     }
   }
 }
+#endif /* NOT USED */
+#define ifnullFunc versionFunc   /* Substitute function - never called */
 
 /*
 ** Implementation of random().  Return a random integer.
 */
 static void randomFunc(
@@ -72160,14 +72306,16 @@
     FUNCTION(round,              2, 0, 0, roundFunc        ),
 #endif
     FUNCTION(upper,              1, 0, 0, upperFunc        ),
     FUNCTION(lower,              1, 0, 0, lowerFunc        ),
     FUNCTION(coalesce,           1, 0, 0, 0                ),
-    FUNCTION(coalesce,          -1, 0, 0, ifnullFunc       ),
     FUNCTION(coalesce,           0, 0, 0, 0                ),
+/*  FUNCTION(coalesce,          -1, 0, 0, ifnullFunc       ), */
+    {-1,SQLITE_UTF8,SQLITE_FUNC_COALESCE,0,0,ifnullFunc,0,0,"coalesce",0},
     FUNCTION(hex,                1, 0, 0, hexFunc          ),
-    FUNCTION(ifnull,             2, 0, 1, ifnullFunc       ),
+/*  FUNCTION(ifnull,             2, 0, 0, ifnullFunc       ), */
+    {2,SQLITE_UTF8,SQLITE_FUNC_COALESCE,0,0,ifnullFunc,0,0,"ifnull",0},
     FUNCTION(random,             0, 0, 0, randomFunc       ),
     FUNCTION(randomblob,         1, 0, 0, randomBlob       ),
     FUNCTION(nullif,             2, 0, 1, nullifFunc       ),
     FUNCTION(sqlite_version,     0, 0, 0, versionFunc      ),
     FUNCTION(sqlite_source_id,   0, 0, 0, sourceidFunc     ),
@@ -72613,11 +72761,11 @@
         sqlite3VdbeAddOp2(v, OP_Goto, 0, iOk);
       }
 
       sqlite3VdbeAddOp3(v, OP_MakeRecord, regTemp, nCol, regRec);
       sqlite3VdbeChangeP4(v, -1, sqlite3IndexAffinityStr(v, pIdx), 0);
-      sqlite3VdbeAddOp3(v, OP_Found, iCur, iOk, regRec);
+      sqlite3VdbeAddOp4Int(v, OP_Found, iCur, iOk, regRec, 0);
 
       sqlite3ReleaseTempReg(pParse, regRec);
       sqlite3ReleaseTempRange(pParse, regTemp, nCol);
     }
   }
@@ -73419,12 +73567,10 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 ** This file contains C code routines that are called by the parser
 ** to handle INSERT statements in SQLite.
-**
-** $Id: insert.c,v 1.270 2009/07/24 17:58:53 danielk1977 Exp $
 */
 
 /*
 ** Generate code that will open a table for reading.
 */
@@ -75240,12 +75386,10 @@
 *************************************************************************
 ** Main file for the SQLite library.  The routines in this file
 ** implement the programmer interface to the library.  Routines in
 ** other files are for internal use by SQLite and should not be
 ** accessed by users of the library.
-**
-** $Id: legacy.c,v 1.35 2009/08/07 16:56:00 danielk1977 Exp $
 */
 
 
 /*
 ** Execute SQL code.  Return one of the SQLITE_ success/failure
@@ -75386,12 +75530,10 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 ** This file contains code used to dynamically load extensions into
 ** the SQLite library.
-**
-** $Id: loadext.c,v 1.60 2009/06/03 01:24:54 drh Exp $
 */
 
 #ifndef SQLITE_CORE
   #define SQLITE_CORE 1  /* Disable the API redefinition in sqlite3ext.h */
 #endif
@@ -75411,12 +75553,10 @@
 ** This header file defines the SQLite interface for use by
 ** shared libraries that want to be imported as extensions into
 ** an SQLite instance.  Shared libraries that intend to be loaded
 ** as extensions by SQLite should #include this file instead of
 ** sqlite3.h.
-**
-** @(#) $Id: sqlite3ext.h,v 1.25 2008/10/12 00:27:54 shane Exp $
 */
 #ifndef _SQLITE3EXT_H_
 #define _SQLITE3EXT_H_
 
 typedef struct sqlite3_api_routines sqlite3_api_routines;
@@ -76380,12 +76520,10 @@
 **    May you find forgiveness for yourself and forgive others.
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 ** This file contains code used to implement the PRAGMA command.
-**
-** $Id: pragma.c,v 1.214 2009/07/02 07:47:33 danielk1977 Exp $
 */
 
 /* Ignore this whole file if pragmas are disabled
 */
 #if !defined(SQLITE_OMIT_PRAGMA)
@@ -77499,10 +77637,11 @@
         sqlite3VdbeAddOp2(v, OP_Integer, 0, 2);  /* reg(2) will count entries */
         loopTop = sqlite3VdbeAddOp2(v, OP_Rewind, 1, 0);
         sqlite3VdbeAddOp2(v, OP_AddImm, 2, 1);   /* increment entry count */
         for(j=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, j++){
           int jmp2;
+          int r1;
           static const VdbeOpList idxErr[] = {
             { OP_AddImm,      1, -1,  0},
             { OP_String8,     0,  3,  0},    /* 1 */
             { OP_Rowid,       1,  4,  0},
             { OP_String8,     0,  5,  0},    /* 3 */
@@ -77512,12 +77651,12 @@
             { OP_Concat,      6,  3,  3},
             { OP_ResultRow,   3,  1,  0},
             { OP_IfPos,       1,  0,  0},    /* 9 */
             { OP_Halt,        0,  0,  0},
           };
-          sqlite3GenerateIndexKey(pParse, pIdx, 1, 3, 1);
-          jmp2 = sqlite3VdbeAddOp3(v, OP_Found, j+2, 0, 3);
+          r1 = sqlite3GenerateIndexKey(pParse, pIdx, 1, 3, 0);
+          jmp2 = sqlite3VdbeAddOp4Int(v, OP_Found, j+2, 0, r1, pIdx->nColumn+1);
           addr = sqlite3VdbeAddOpList(v, ArraySize(idxErr), idxErr);
           sqlite3VdbeChangeP4(v, addr+1, "rowid ", P4_STATIC);
           sqlite3VdbeChangeP4(v, addr+3, " missing from index ", P4_STATIC);
           sqlite3VdbeChangeP4(v, addr+4, pIdx->zName, P4_STATIC);
           sqlite3VdbeJumpHere(v, addr+9);
@@ -77820,12 +77959,10 @@
 **
 *************************************************************************
 ** This file contains the implementation of the sqlite3_prepare()
 ** interface, and routines that contribute to loading the database schema
 ** from disk.
-**
-** $Id: prepare.c,v 1.131 2009/08/06 17:43:31 drh Exp $
 */
 
 /*
 ** Fill the InitData structure with an error message that indicates
 ** that the database is corrupt.
@@ -78694,12 +78831,10 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 ** This file contains C code routines that are called by the parser
 ** to handle SELECT statements in SQLite.
-**
-** $Id: select.c,v 1.526 2009/08/01 15:09:58 drh Exp $
 */
 
 
 /*
 ** Delete all the content of a Select structure but do not deallocate
@@ -79123,12 +79258,12 @@
   Vdbe *v;
   int r1;
 
   v = pParse->pVdbe;
   r1 = sqlite3GetTempReg(pParse);
-  sqlite3VdbeAddOp3(v, OP_MakeRecord, iMem, N, r1);
-  sqlite3VdbeAddOp3(v, OP_Found, iTab, addrRepeat, r1);
+  sqlite3VdbeAddOp4Int(v, OP_Found, iTab, addrRepeat, iMem, N);
+  sqlite3VdbeAddOp3(v, OP_MakeRecord, iMem, N, r1);
   sqlite3VdbeAddOp2(v, OP_IdxInsert, iTab, r1);
   sqlite3ReleaseTempReg(pParse, r1);
 }
 
 /*
@@ -79365,12 +79500,11 @@
   /* Jump to the end of the loop if the LIMIT is reached.
   */
   if( p->iLimit ){
     assert( pOrderBy==0 );  /* If there is an ORDER BY, the call to
                             ** pushOntoSorter() would have cleared p->iLimit */
-    sqlite3VdbeAddOp2(v, OP_AddImm, p->iLimit, -1);
-    sqlite3VdbeAddOp2(v, OP_IfZero, p->iLimit, iBreak);
+    sqlite3VdbeAddOp3(v, OP_IfZero, p->iLimit, iBreak, -1);
   }
 }
 
 /*
 ** Given an expression list, generate a KeyInfo structure that records
@@ -79992,11 +80126,11 @@
 */
 static void computeLimitRegisters(Parse *pParse, Select *p, int iBreak){
   Vdbe *v = 0;
   int iLimit = 0;
   int iOffset;
-  int addr1;
+  int addr1, n;
   if( p->iLimit ) return;
 
   /*
   ** "LIMIT -1" always shows all rows.  There is some
   ** contraversy about what the correct behavior should be.
@@ -80007,14 +80141,22 @@
   assert( p->pOffset==0 || p->pLimit!=0 );
   if( p->pLimit ){
     p->iLimit = iLimit = ++pParse->nMem;
     v = sqlite3GetVdbe(pParse);
     if( NEVER(v==0) ) return;  /* VDBE should have already been allocated */
-    sqlite3ExprCode(pParse, p->pLimit, iLimit);
-    sqlite3VdbeAddOp1(v, OP_MustBeInt, iLimit);
-    VdbeComment((v, "LIMIT counter"));
-    sqlite3VdbeAddOp2(v, OP_IfZero, iLimit, iBreak);
+    if( sqlite3ExprIsInteger(p->pLimit, &n) ){
+      sqlite3VdbeAddOp2(v, OP_Integer, n, iLimit);
+      VdbeComment((v, "LIMIT counter"));
+      if( n==0 ){
+        sqlite3VdbeAddOp2(v, OP_Goto, 0, iBreak);
+      }
+    }else{
+      sqlite3ExprCode(pParse, p->pLimit, iLimit);
+      sqlite3VdbeAddOp1(v, OP_MustBeInt, iLimit);
+      VdbeComment((v, "LIMIT counter"));
+      sqlite3VdbeAddOp2(v, OP_IfZero, iLimit, iBreak);
+    }
     if( p->pOffset ){
       p->iOffset = iOffset = ++pParse->nMem;
       pParse->nMem++;   /* Allocate an extra register for limit+offset */
       sqlite3ExprCode(pParse, p->pOffset, iOffset);
       sqlite3VdbeAddOp1(v, OP_MustBeInt, iOffset);
@@ -80346,11 +80488,11 @@
       iCont = sqlite3VdbeMakeLabel(v);
       computeLimitRegisters(pParse, p, iBreak);
       sqlite3VdbeAddOp2(v, OP_Rewind, tab1, iBreak);
       r1 = sqlite3GetTempReg(pParse);
       iStart = sqlite3VdbeAddOp2(v, OP_RowKey, tab1, r1);
-      sqlite3VdbeAddOp3(v, OP_NotFound, tab2, iCont, r1);
+      sqlite3VdbeAddOp4Int(v, OP_NotFound, tab2, iCont, r1, 0);
       sqlite3ReleaseTempReg(pParse, r1);
       selectInnerLoop(pParse, p, p->pEList, tab1, p->pEList->nExpr,
                       0, -1, &dest, iCont, iBreak);
       sqlite3VdbeResolveLabel(v, iCont);
       sqlite3VdbeAddOp2(v, OP_Next, tab1, iStart);
@@ -80565,12 +80707,11 @@
   }
 
   /* Jump to the end of the loop if the LIMIT is reached.
   */
   if( p->iLimit ){
-    sqlite3VdbeAddOp2(v, OP_AddImm, p->iLimit, -1);
-    sqlite3VdbeAddOp2(v, OP_IfZero, p->iLimit, iBreak);
+    sqlite3VdbeAddOp3(v, OP_IfZero, p->iLimit, iBreak, -1);
   }
 
   /* Generate the subroutine return
   */
   sqlite3VdbeResolveLabel(v, iContinue);
@@ -82934,12 +83075,10 @@
 ** interface routines.  These are just wrappers around the main
 ** interface routine of sqlite3_exec().
 **
 ** These routines are in a separate files so that they will not be linked
 ** if they are not used.
-**
-** $Id: table.c,v 1.40 2009/04/10 14:28:00 drh Exp $
 */
 
 #ifndef SQLITE_OMIT_GET_TABLE
 
 /*
@@ -83126,13 +83265,11 @@
 **    May you do good and not evil.
 **    May you find forgiveness for yourself and forgive others.
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
-**
-**
-** $Id: trigger.c,v 1.143 2009/08/10 03:57:58 shane Exp $
+** This file contains the implementation for TRIGGERs
 */
 
 #ifndef SQLITE_OMIT_TRIGGER
 /*
 ** Delete a linked list of TriggerStep structures.
@@ -84210,12 +84347,10 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 ** This file contains C code routines that are called by the parser
 ** to handle UPDATE statements.
-**
-** $Id: update.c,v 1.207 2009/08/08 18:01:08 drh Exp $
 */
 
 #ifndef SQLITE_OMIT_VIRTUALTABLE
 /* Forward declaration */
 static void updateVirtualTable(
@@ -84843,12 +84978,10 @@
 *************************************************************************
 ** This file contains code used to implement the VACUUM command.
 **
 ** Most of the code in this file may be omitted by defining the
 ** SQLITE_OMIT_VACUUM macro.
-**
-** $Id: vacuum.c,v 1.91 2009/07/02 07:47:33 danielk1977 Exp $
 */
 
 #if !defined(SQLITE_OMIT_VACUUM) && !defined(SQLITE_OMIT_ATTACH)
 /*
 ** Execute zSql on database db. Return an error code.
@@ -85149,12 +85282,10 @@
 **    May you find forgiveness for yourself and forgive others.
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 ** This file contains code used to help implement virtual tables.
-**
-** $Id: vtab.c,v 1.94 2009/08/08 18:01:08 drh Exp $
 */
 #ifndef SQLITE_OMIT_VIRTUALTABLE
 
 /*
 ** The actual function that does the work of creating a new module.
@@ -86118,12 +86249,10 @@
 ** the WHERE clause of SQL statements.  This module is responsible for
 ** generating the code that loops through a table looking for applicable
 ** rows.  Indices are selected and used to speed the search when doing
 ** so is applicable.  Because this module is responsible for selecting
 ** indices, you might also think of this module as the "query optimizer".
-**
-** $Id: where.c,v 1.411 2009/07/31 06:14:52 danielk1977 Exp $
 */
 
 /*
 ** Trace output macros
 */
@@ -88698,20 +88827,43 @@
 
 /*
 ** Code an OP_Affinity opcode to apply the column affinity string zAff
 ** to the n registers starting at base.
 **
-** Buffer zAff was allocated using sqlite3DbMalloc(). It is the
-** responsibility of this function to arrange for it to be eventually
-** freed using sqlite3DbFree().
+** As an optimization, SQLITE_AFF_NONE entries (which are no-ops) at the
+** beginning and end of zAff are ignored.  If all entries in zAff are
+** SQLITE_AFF_NONE, then no code gets generated.
+**
+** This routine makes its own copy of zAff so that the caller is free
+** to modify zAff after this routine returns.
 */
 static void codeApplyAffinity(Parse *pParse, int base, int n, char *zAff){
   Vdbe *v = pParse->pVdbe;
+  if( zAff==0 ){
+    assert( pParse->db->mallocFailed );
+    return;
+  }
   assert( v!=0 );
-  sqlite3VdbeAddOp2(v, OP_Affinity, base, n);
-  sqlite3VdbeChangeP4(v, -1, zAff, P4_DYNAMIC);
-  sqlite3ExprCacheAffinityChange(pParse, base, n);
+
+  /* Adjust base and n to skip over SQLITE_AFF_NONE entries at the beginning
+  ** and end of the affinity string.
+  */
+  while( n>0 && zAff[0]==SQLITE_AFF_NONE ){
+    n--;
+    base++;
+    zAff++;
+  }
+  while( n>1 && zAff[n-1]==SQLITE_AFF_NONE ){
+    n--;
+  }
+
+  /* Code the OP_Affinity opcode if there is anything left to do. */
+  if( n>0 ){
+    sqlite3VdbeAddOp2(v, OP_Affinity, base, n);
+    sqlite3VdbeChangeP4(v, -1, zAff, n);
+    sqlite3ExprCacheAffinityChange(pParse, base, n);
+  }
 }
 
 
 /*
 ** Generate code for a single equality term of the WHERE clause.  An equality
@@ -88778,11 +88930,11 @@
   return iReg;
 }
 
 /*
 ** Generate code that will evaluate all == and IN constraints for an
-** index.  The values for all constraints are left on the stack.
+** index.
 **
 ** For example, consider table t1(a,b,c,d,e,f) with index i1(a,b,c).
 ** Suppose the WHERE clause is this:  a==5 AND b IN (1,2,3) AND c>5 AND c<10
 ** The index has as many as three equality constraints, but in this
 ** example, the third "c" value is an inequality.  So only two
@@ -88790,11 +88942,12 @@
 ** a==5 and b IN (1,2,3).  The current values for a and b will be stored
 ** in consecutive registers and the index of the first register is returned.
 **
 ** In the example above nEq==2.  But this subroutine works for any value
 ** of nEq including 0.  If nEq==0, this routine is nearly a no-op.
-** The only thing it does is allocate the pLevel->iMem memory cell.
+** The only thing it does is allocate the pLevel->iMem memory cell and
+** compute the affinity string.
 **
 ** This routine always allocates at least one memory cell and returns
 ** the index of that memory cell. The code that
 ** calls this routine will use that memory cell to store the termination
 ** key value of the loop.  If one or more IN operators appear, then
@@ -88868,15 +89021,19 @@
       }
     }
     testcase( pTerm->eOperator & WO_ISNULL );
     testcase( pTerm->eOperator & WO_IN );
     if( (pTerm->eOperator & (WO_ISNULL|WO_IN))==0 ){
-      sqlite3VdbeAddOp2(v, OP_IsNull, regBase+j, pLevel->addrBrk);
-      if( zAff
-       && sqlite3CompareAffinity(pTerm->pExpr->pRight, zAff[j])==SQLITE_AFF_NONE
-      ){
-        zAff[j] = SQLITE_AFF_NONE;
+      Expr *pRight = pTerm->pExpr->pRight;
+      sqlite3ExprCodeIsNullJump(v, pRight, regBase+j, pLevel->addrBrk);
+      if( zAff ){
+        if( sqlite3CompareAffinity(pRight, zAff[j])==SQLITE_AFF_NONE ){
+          zAff[j] = SQLITE_AFF_NONE;
+        }
+        if( sqlite3ExprNeedsNoAffinityChange(pRight, zAff[j]) ){
+          zAff[j] = SQLITE_AFF_NONE;
+        }
       }
     }
   }
   *pzAff = zAff;
   return regBase;
@@ -89198,18 +89355,21 @@
     /* Seek the index cursor to the start of the range. */
     nConstraint = nEq;
     if( pRangeStart ){
       Expr *pRight = pRangeStart->pExpr->pRight;
       sqlite3ExprCode(pParse, pRight, regBase+nEq);
-      sqlite3VdbeAddOp2(v, OP_IsNull, regBase+nEq, addrNxt);
-      if( zAff
-       && sqlite3CompareAffinity(pRight, zAff[nConstraint])==SQLITE_AFF_NONE
-      ){
-        /* Since the comparison is to be performed with no conversions applied
-        ** to the operands, set the affinity to apply to pRight to
-        ** SQLITE_AFF_NONE.  */
-        zAff[nConstraint] = SQLITE_AFF_NONE;
+      sqlite3ExprCodeIsNullJump(v, pRight, regBase+nEq, addrNxt);
+      if( zAff ){
+        if( sqlite3CompareAffinity(pRight, zAff[nConstraint])==SQLITE_AFF_NONE){
+          /* Since the comparison is to be performed with no conversions
+          ** applied to the operands, set the affinity to apply to pRight to
+          ** SQLITE_AFF_NONE.  */
+          zAff[nConstraint] = SQLITE_AFF_NONE;
+        }
+        if( sqlite3ExprNeedsNoAffinityChange(pRight, zAff[nConstraint]) ){
+          zAff[nConstraint] = SQLITE_AFF_NONE;
+        }
       }
       nConstraint++;
     }else if( isMinQuery ){
       sqlite3VdbeAddOp2(v, OP_Null, 0, regBase+nEq);
       nConstraint++;
@@ -89223,34 +89383,36 @@
     testcase( op==OP_Last );
     testcase( op==OP_SeekGt );
     testcase( op==OP_SeekGe );
     testcase( op==OP_SeekLe );
     testcase( op==OP_SeekLt );
-    sqlite3VdbeAddOp4(v, op, iIdxCur, addrNxt, regBase,
-                      SQLITE_INT_TO_PTR(nConstraint), P4_INT32);
+    sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint);
 
     /* Load the value for the inequality constraint at the end of the
     ** range (if any).
     */
     nConstraint = nEq;
     if( pRangeEnd ){
       Expr *pRight = pRangeEnd->pExpr->pRight;
       sqlite3ExprCacheRemove(pParse, regBase+nEq);
       sqlite3ExprCode(pParse, pRight, regBase+nEq);
-      sqlite3VdbeAddOp2(v, OP_IsNull, regBase+nEq, addrNxt);
-      zAff = sqlite3DbStrDup(pParse->db, zAff);
-      if( zAff
-       && sqlite3CompareAffinity(pRight, zAff[nConstraint])==SQLITE_AFF_NONE
-      ){
-        /* Since the comparison is to be performed with no conversions applied
-        ** to the operands, set the affinity to apply to pRight to
-        ** SQLITE_AFF_NONE.  */
-        zAff[nConstraint] = SQLITE_AFF_NONE;
+      sqlite3ExprCodeIsNullJump(v, pRight, regBase+nEq, addrNxt);
+      if( zAff ){
+        if( sqlite3CompareAffinity(pRight, zAff[nConstraint])==SQLITE_AFF_NONE){
+          /* Since the comparison is to be performed with no conversions
+          ** applied to the operands, set the affinity to apply to pRight to
+          ** SQLITE_AFF_NONE.  */
+          zAff[nConstraint] = SQLITE_AFF_NONE;
+        }
+        if( sqlite3ExprNeedsNoAffinityChange(pRight, zAff[nConstraint]) ){
+          zAff[nConstraint] = SQLITE_AFF_NONE;
+        }
       }
       codeApplyAffinity(pParse, regBase, nEq+1, zAff);
       nConstraint++;
     }
+    sqlite3DbFree(pParse->db, zAff);
 
     /* Top of the loop body */
     pLevel->p2 = sqlite3VdbeCurrentAddr(v);
 
     /* Check if the index cursor is past the end of the range. */
@@ -89257,12 +89419,11 @@
     op = aEndOp[(pRangeEnd || nEq) * (1 + bRev)];
     testcase( op==OP_Noop );
     testcase( op==OP_IdxGE );
     testcase( op==OP_IdxLT );
     if( op!=OP_Noop ){
-      sqlite3VdbeAddOp4(v, op, iIdxCur, addrNxt, regBase,
-                        SQLITE_INT_TO_PTR(nConstraint), P4_INT32);
+      sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint);
       sqlite3VdbeChangeP5(v, endEq!=bRev ?1:0);
     }
 
     /* If there are inequality constraints, check that the value
     ** of the table column that the inequality contrains is not NULL.
@@ -89387,13 +89548,12 @@
           if( (wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
             int iSet = ((ii==pOrWc->nTerm-1)?-1:ii);
             int r;
             r = sqlite3ExprCodeGetColumn(pParse, pTabItem->pTab, -1, iCur,
                                          regRowid, 0);
-            sqlite3VdbeAddOp4(v, OP_RowSetTest, regRowset,
-                              sqlite3VdbeCurrentAddr(v)+2,
-                              r, SQLITE_INT_TO_PTR(iSet), P4_INT32);
+            sqlite3VdbeAddOp4Int(v, OP_RowSetTest, regRowset,
+                                 sqlite3VdbeCurrentAddr(v)+2, r, iSet);
           }
           sqlite3VdbeAddOp2(v, OP_Gosub, regReturn, iLoopBody);
 
           /* Finish the loop through table entries that match term pOrTerm. */
           sqlite3WhereEnd(pSubWInfo);
@@ -89920,11 +90080,12 @@
       sqlite3OpenTable(pParse, pTabItem->iCursor, iDb, pTab, op);
       if( !pWInfo->okOnePass && pTab->nCol<BMS ){
         Bitmask b = pTabItem->colUsed;
         int n = 0;
         for(; b; b=b>>1, n++){}
-        sqlite3VdbeChangeP4(v, sqlite3VdbeCurrentAddr(v)-1, SQLITE_INT_TO_PTR(n), P4_INT32);
+        sqlite3VdbeChangeP4(v, sqlite3VdbeCurrentAddr(v)-1,
+                            SQLITE_INT_TO_PTR(n), P4_INT32);
         assert( n<=pTab->nCol );
       }
     }else{
       sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
     }
@@ -90048,11 +90209,15 @@
     }
     sqlite3VdbeResolveLabel(v, pLevel->addrBrk);
     if( pLevel->iLeftJoin ){
       int addr;
       addr = sqlite3VdbeAddOp1(v, OP_IfPos, pLevel->iLeftJoin);
-      sqlite3VdbeAddOp1(v, OP_NullRow, pTabList->a[i].iCursor);
+      assert( (pLevel->plan.wsFlags & WHERE_IDX_ONLY)==0
+           || (pLevel->plan.wsFlags & WHERE_INDEXED)!=0 );
+      if( (pLevel->plan.wsFlags & WHERE_IDX_ONLY)==0 ){
+        sqlite3VdbeAddOp1(v, OP_NullRow, pTabList->a[i].iCursor);
+      }
       if( pLevel->iIdxCur>=0 ){
         sqlite3VdbeAddOp1(v, OP_NullRow, pLevel->iIdxCur);
       }
       if( pLevel->op==OP_Return ){
         sqlite3VdbeAddOp2(v, OP_Gosub, pLevel->p1, pLevel->addrFirst);
@@ -90099,11 +90264,10 @@
     */
     if( (pLevel->plan.wsFlags & WHERE_INDEXED)!=0 && !db->mallocFailed){
       int k, j, last;
       VdbeOp *pOp;
       Index *pIdx = pLevel->plan.u.pIdx;
-      int useIndexOnly = pLevel->plan.wsFlags & WHERE_IDX_ONLY;
 
       assert( pIdx!=0 );
       pOp = sqlite3VdbeGetOp(v, pWInfo->iTop);
       last = sqlite3VdbeCurrentAddr(v);
       for(k=pWInfo->iTop; k<last; k++, pOp++){
@@ -90114,16 +90278,15 @@
               pOp->p2 = j;
               pOp->p1 = pLevel->iIdxCur;
               break;
             }
           }
-          assert(!useIndexOnly || j<pIdx->nColumn);
+          assert( (pLevel->plan.wsFlags & WHERE_IDX_ONLY)==0
+               || j<pIdx->nColumn );
         }else if( pOp->opcode==OP_Rowid ){
           pOp->p1 = pLevel->iIdxCur;
           pOp->opcode = OP_IdxRowid;
-        }else if( pOp->opcode==OP_NullRow && useIndexOnly ){
-          pOp->opcode = OP_Noop;
         }
       }
     }
   }
 
@@ -90238,10 +90401,21 @@
     Token *pPostOp         /* The operand token for setting the span */
   ){
     pOut->pExpr = sqlite3PExpr(pParse, op, pOperand->pExpr, 0, 0);
     pOut->zStart = pOperand->zStart;
     pOut->zEnd = &pPostOp->z[pPostOp->n];
+  }
+
+  /* A routine to convert a binary TK_IS or TK_ISNOT expression into a
+  ** unary TK_ISNULL or TK_NOTNULL expression. */
+  static void binaryToUnaryIfNull(Parse *pParse, Expr *pY, Expr *pA, int op){
+    sqlite3 *db = pParse->db;
+    if( db->mallocFailed==0 && pY->op==TK_NULL ){
+      pA->op = op;
+      sqlite3ExprDelete(db, pA->pRight);
+      pA->pRight = 0;
+    }
   }
 
   /* Construct an expression node for a unary prefix operator
   */
   static void spanUnaryPrefix(
@@ -92857,21 +93031,17 @@
 {spanUnaryPostfix(&yygotominor.yy346,pParse,TK_NOTNULL,&yymsp[-2].minor.yy346,&yymsp[0].minor.yy0);}
         break;
       case 216: /* expr ::= expr IS expr */
 {
   spanBinaryExpr(&yygotominor.yy346,pParse,TK_IS,&yymsp[-2].minor.yy346,&yymsp[0].minor.yy346);
-  if( pParse->db->mallocFailed==0  && yymsp[0].minor.yy346.pExpr->op==TK_NULL ){
-    yygotominor.yy346.pExpr->op = TK_ISNULL;
-  }
+  binaryToUnaryIfNull(pParse, yymsp[0].minor.yy346.pExpr, yygotominor.yy346.pExpr, TK_ISNULL);
 }
         break;
       case 217: /* expr ::= expr IS NOT expr */
 {
   spanBinaryExpr(&yygotominor.yy346,pParse,TK_ISNOT,&yymsp[-3].minor.yy346,&yymsp[0].minor.yy346);
-  if( pParse->db->mallocFailed==0  && yymsp[0].minor.yy346.pExpr->op==TK_NULL ){
-    yygotominor.yy346.pExpr->op = TK_NOTNULL;
-  }
+  binaryToUnaryIfNull(pParse, yymsp[0].minor.yy346.pExpr, yygotominor.yy346.pExpr, TK_NOTNULL);
 }
         break;
       case 218: /* expr ::= NOT expr */
       case 219: /* expr ::= BITNOT expr */ yytestcase(yyruleno==219);
 {spanUnaryPrefix(&yygotominor.yy346,pParse,yymsp[-1].major,&yymsp[0].minor.yy346,&yymsp[-1].minor.yy0);}
@@ -93551,12 +93721,10 @@
 ** An tokenizer for SQL
 **
 ** This file contains C code that splits an SQL input string up into
 ** individual tokens and sends those tokens one-by-one over to the
 ** parser for analysis.
-**
-** $Id: tokenize.c,v 1.163 2009/07/03 22:54:37 drh Exp $
 */
 
 /*
 ** The charMap() macro maps alphabetic characters into their
 ** lower-case ASCII equivalent.  On ASCII machines, this is just
@@ -93892,20 +94060,11 @@
 ** middle of identfiers.  But many SQL implementations do.
 ** SQLite will allow '$' in identifiers for compatibility.
 ** But the feature is undocumented.
 */
 #ifdef SQLITE_ASCII
-SQLITE_PRIVATE const char sqlite3IsAsciiIdChar[] = {
-/* x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 xA xB xC xD xE xF */
-    0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 2x */
-    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,  /* 3x */
-    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 4x */
-    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1,  /* 5x */
-    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 6x */
-    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0,  /* 7x */
-};
-#define IdChar(C)  (((c=C)&0x80)!=0 || (c>0x1f && sqlite3IsAsciiIdChar[c-0x20]))
+#define IdChar(C)  ((sqlite3CtypeMap[(unsigned char)C]&0x46)!=0)
 #endif
 #ifdef SQLITE_EBCDIC
 SQLITE_PRIVATE const char sqlite3IsEbcdicIdChar[] = {
 /* x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 xA xB xC xD xE xF */
     0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,  /* 4x */
@@ -94361,22 +94520,19 @@
 **
 ** This file contains C code that implements the sqlite3_complete() API.
 ** This code used to be part of the tokenizer.c source file.  But by
 ** separating it out, the code will be automatically omitted from
 ** static links that do not use it.
-**
-** $Id: complete.c,v 1.8 2009/04/28 04:46:42 drh Exp $
 */
 #ifndef SQLITE_OMIT_COMPLETE
 
 /*
 ** This is defined in tokenize.c.  We just have to import the definition.
 */
 #ifndef SQLITE_AMALGAMATION
 #ifdef SQLITE_ASCII
-SQLITE_PRIVATE const char sqlite3IsAsciiIdChar[];
-#define IdChar(C)  (((c=C)&0x80)!=0 || (c>0x1f && sqlite3IsAsciiIdChar[c-0x20]))
+#define IdChar(C)  ((sqlite3CtypeMap[(unsigned char)C]&0x46)!=0)
 #endif
 #ifdef SQLITE_EBCDIC
 SQLITE_PRIVATE const char sqlite3IsEbcdicIdChar[];
 #define IdChar(C)  (((c=C)>=0x42 && sqlite3IsEbcdicIdChar[c-0x40]))
 #endif
@@ -94529,11 +94685,13 @@
         if( *zSql==0 ) return 0;
         token = tkOTHER;
         break;
       }
       default: {
-        int c;
+#ifdef SQLITE_EBCDIC
+        unsigned char c;
+#endif
         if( IdChar((u8)*zSql) ){
           /* Keywords and unquoted identifiers */
           int nId;
           for(nId=1; IdChar(zSql[nId]); nId++){}
 #ifdef SQLITE_OMIT_TRIGGER
@@ -97015,12 +97173,10 @@
 **
 *************************************************************************
 **
 ** This file contains the implementation of the sqlite3_unlock_notify()
 ** API method and its associated functionality.
-**
-** $Id: notify.c,v 1.4 2009/04/07 22:06:57 drh Exp $
 */
 
 /* Omit this entire file if SQLITE_ENABLE_UNLOCK_NOTIFY is not defined. */
 #ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
 
@@ -97615,380 +97771,17 @@
 
 #if defined(SQLITE_ENABLE_FTS3) && !defined(SQLITE_CORE)
 # define SQLITE_CORE 1
 #endif
 
-
-/************** Include fts3_expr.h in the middle of fts3.c ******************/
-/************** Begin file fts3_expr.h ***************************************/
-/*
-** 2008 Nov 28
-**
-** The author disclaims copyright to this source code.  In place of
-** a legal notice, here is a blessing:
-**
-**    May you do good and not evil.
-**    May you find forgiveness for yourself and forgive others.
-**    May you share freely, never taking more than you give.
-**
-******************************************************************************
-**
-*/
-
-/************** Include fts3_tokenizer.h in the middle of fts3_expr.h ********/
-/************** Begin file fts3_tokenizer.h **********************************/
-/*
-** 2006 July 10
-**
-** The author disclaims copyright to this source code.
-**
-*************************************************************************
-** Defines the interface to tokenizers used by fulltext-search.  There
-** are three basic components:
-**
-** sqlite3_tokenizer_module is a singleton defining the tokenizer
-** interface functions.  This is essentially the class structure for
-** tokenizers.
-**
-** sqlite3_tokenizer is used to define a particular tokenizer, perhaps
-** including customization information defined at creation time.
-**
-** sqlite3_tokenizer_cursor is generated by a tokenizer to generate
-** tokens from a particular input.
-*/
-#ifndef _FTS3_TOKENIZER_H_
-#define _FTS3_TOKENIZER_H_
-
-/* TODO(shess) Only used for SQLITE_OK and SQLITE_DONE at this time.
-** If tokenizers are to be allowed to call sqlite3_*() functions, then
-** we will need a way to register the API consistently.
-*/
-
-/*
-** Structures used by the tokenizer interface. When a new tokenizer
-** implementation is registered, the caller provides a pointer to
-** an sqlite3_tokenizer_module containing pointers to the callback
-** functions that make up an implementation.
-**
-** When an fts3 table is created, it passes any arguments passed to
-** the tokenizer clause of the CREATE VIRTUAL TABLE statement to the
-** sqlite3_tokenizer_module.xCreate() function of the requested tokenizer
-** implementation. The xCreate() function in turn returns an
-** sqlite3_tokenizer structure representing the specific tokenizer to
-** be used for the fts3 table (customized by the tokenizer clause arguments).
-**
-** To tokenize an input buffer, the sqlite3_tokenizer_module.xOpen()
-** method is called. It returns an sqlite3_tokenizer_cursor object
-** that may be used to tokenize a specific input buffer based on
-** the tokenization rules supplied by a specific sqlite3_tokenizer
-** object.
-*/
-typedef struct sqlite3_tokenizer_module sqlite3_tokenizer_module;
-typedef struct sqlite3_tokenizer sqlite3_tokenizer;
-typedef struct sqlite3_tokenizer_cursor sqlite3_tokenizer_cursor;
-
-struct sqlite3_tokenizer_module {
-
-  /*
-  ** Structure version. Should always be set to 0.
-  */
-  int iVersion;
-
-  /*
-  ** Create a new tokenizer. The values in the argv[] array are the
-  ** arguments passed to the "tokenizer" clause of the CREATE VIRTUAL
-  ** TABLE statement that created the fts3 table. For example, if
-  ** the following SQL is executed:
-  **
-  **   CREATE .. USING fts3( ... , tokenizer <tokenizer-name> arg1 arg2)
-  **
-  ** then argc is set to 2, and the argv[] array contains pointers
-  ** to the strings "arg1" and "arg2".
-  **
-  ** This method should return either SQLITE_OK (0), or an SQLite error
-  ** code. If SQLITE_OK is returned, then *ppTokenizer should be set
-  ** to point at the newly created tokenizer structure. The generic
-  ** sqlite3_tokenizer.pModule variable should not be initialised by
-  ** this callback. The caller will do so.
-  */
-  int (*xCreate)(
-    int argc,                           /* Size of argv array */
-    const char *const*argv,             /* Tokenizer argument strings */
-    sqlite3_tokenizer **ppTokenizer     /* OUT: Created tokenizer */
-  );
-
-  /*
-  ** Destroy an existing tokenizer. The fts3 module calls this method
-  ** exactly once for each successful call to xCreate().
-  */
-  int (*xDestroy)(sqlite3_tokenizer *pTokenizer);
-
-  /*
-  ** Create a tokenizer cursor to tokenize an input buffer. The caller
-  ** is responsible for ensuring that the input buffer remains valid
-  ** until the cursor is closed (using the xClose() method).
-  */
-  int (*xOpen)(
-    sqlite3_tokenizer *pTokenizer,       /* Tokenizer object */
-    const char *pInput, int nBytes,      /* Input buffer */
-    sqlite3_tokenizer_cursor **ppCursor  /* OUT: Created tokenizer cursor */
-  );
-
-  /*
-  ** Destroy an existing tokenizer cursor. The fts3 module calls this
-  ** method exactly once for each successful call to xOpen().
-  */
-  int (*xClose)(sqlite3_tokenizer_cursor *pCursor);
-
-  /*
-  ** Retrieve the next token from the tokenizer cursor pCursor. This
-  ** method should either return SQLITE_OK and set the values of the
-  ** "OUT" variables identified below, or SQLITE_DONE to indicate that
-  ** the end of the buffer has been reached, or an SQLite error code.
-  **
-  ** *ppToken should be set to point at a buffer containing the
-  ** normalized version of the token (i.e. after any case-folding and/or
-  ** stemming has been performed). *pnBytes should be set to the length
-  ** of this buffer in bytes. The input text that generated the token is
-  ** identified by the byte offsets returned in *piStartOffset and
-  ** *piEndOffset. *piStartOffset should be set to the index of the first
-  ** byte of the token in the input buffer. *piEndOffset should be set
-  ** to the index of the first byte just past the end of the token in
-  ** the input buffer.
-  **
-  ** The buffer *ppToken is set to point at is managed by the tokenizer
-  ** implementation. It is only required to be valid until the next call
-  ** to xNext() or xClose().
-  */
-  /* TODO(shess) current implementation requires pInput to be
-  ** nul-terminated.  This should either be fixed, or pInput/nBytes
-  ** should be converted to zInput.
-  */
-  int (*xNext)(
-    sqlite3_tokenizer_cursor *pCursor,   /* Tokenizer cursor */
-    const char **ppToken, int *pnBytes,  /* OUT: Normalized text for token */
-    int *piStartOffset,  /* OUT: Byte offset of token in input buffer */
-    int *piEndOffset,    /* OUT: Byte offset of end of token in input buffer */
-    int *piPosition      /* OUT: Number of tokens returned before this one */
-  );
-};
-
-struct sqlite3_tokenizer {
-  const sqlite3_tokenizer_module *pModule;  /* The module for this tokenizer */
-  /* Tokenizer implementations will typically add additional fields */
-};
-
-struct sqlite3_tokenizer_cursor {
-  sqlite3_tokenizer *pTokenizer;       /* Tokenizer for this cursor. */
-  /* Tokenizer implementations will typically add additional fields */
-};
-
-#endif /* _FTS3_TOKENIZER_H_ */
-
-/************** End of fts3_tokenizer.h **************************************/
-/************** Continuing where we left off in fts3_expr.h ******************/
-
-/*
-** The following describes the syntax supported by the fts3 MATCH
-** operator in a similar format to that used by the lemon parser
-** generator. This module does not use actually lemon, it uses a
-** custom parser.
-**
-**   query ::= andexpr (OR andexpr)*.
-**
-**   andexpr ::= notexpr (AND? notexpr)*.
-**
-**   notexpr ::= nearexpr (NOT nearexpr|-TOKEN)*.
-**   notexpr ::= LP query RP.
-**
-**   nearexpr ::= phrase (NEAR distance_opt nearexpr)*.
-**
-**   distance_opt ::= .
-**   distance_opt ::= / INTEGER.
-**
-**   phrase ::= TOKEN.
-**   phrase ::= COLUMN:TOKEN.
-**   phrase ::= "TOKEN TOKEN TOKEN...".
-*/
-
-typedef struct Fts3Expr Fts3Expr;
-typedef struct Fts3Phrase Fts3Phrase;
-
-/*
-** A "phrase" is a sequence of one or more tokens that must match in
-** sequence.  A single token is the base case and the most common case.
-** For a sequence of tokens contained in "...", nToken will be the number
-** of tokens in the string.
-*/
-struct Fts3Phrase {
-  int nToken;          /* Number of tokens in the phrase */
-  int iColumn;         /* Index of column this phrase must match */
-  int isNot;           /* Phrase prefixed by unary not (-) operator */
-  struct PhraseToken {
-    char *z;              /* Text of the token */
-    int n;                /* Number of bytes in buffer pointed to by z */
-    int isPrefix;         /* True if token ends in with a "*" character */
-  } aToken[1];         /* One entry for each token in the phrase */
-};
-
-/*
-** A tree of these objects forms the RHS of a MATCH operator.
-*/
-struct Fts3Expr {
-  int eType;                 /* One of the FTSQUERY_XXX values defined below */
-  int nNear;                 /* Valid if eType==FTSQUERY_NEAR */
-  Fts3Expr *pParent;         /* pParent->pLeft==this or pParent->pRight==this */
-  Fts3Expr *pLeft;           /* Left operand */
-  Fts3Expr *pRight;          /* Right operand */
-  Fts3Phrase *pPhrase;       /* Valid if eType==FTSQUERY_PHRASE */
-};
-
-SQLITE_PRIVATE int sqlite3Fts3ExprParse(sqlite3_tokenizer *, char **, int, int,
-                         const char *, int, Fts3Expr **);
-SQLITE_PRIVATE void sqlite3Fts3ExprFree(Fts3Expr *);
-
-/*
-** Candidate values for Fts3Query.eType. Note that the order of the first
-** four values is in order of precedence when parsing expressions. For
-** example, the following:
-**
-**   "a OR b AND c NOT d NEAR e"
-**
-** is equivalent to:
-**
-**   "a OR (b AND (c NOT (d NEAR e)))"
-*/
-#define FTSQUERY_NEAR   1
-#define FTSQUERY_NOT    2
-#define FTSQUERY_AND    3
-#define FTSQUERY_OR     4
-#define FTSQUERY_PHRASE 5
-
-#ifdef SQLITE_TEST
-SQLITE_PRIVATE void sqlite3Fts3ExprInitTestInterface(sqlite3 *db);
-#endif
-
-/************** End of fts3_expr.h *******************************************/
-/************** Continuing where we left off in fts3.c ***********************/
-/************** Include fts3_hash.h in the middle of fts3.c ******************/
-/************** Begin file fts3_hash.h ***************************************/
-/*
-** 2001 September 22
-**
-** The author disclaims copyright to this source code.  In place of
-** a legal notice, here is a blessing:
-**
-**    May you do good and not evil.
-**    May you find forgiveness for yourself and forgive others.
-**    May you share freely, never taking more than you give.
-**
-*************************************************************************
-** This is the header file for the generic hash-table implemenation
-** used in SQLite.  We've modified it slightly to serve as a standalone
-** hash table implementation for the full-text indexing module.
-**
-*/
-#ifndef _FTS3_HASH_H_
-#define _FTS3_HASH_H_
-
-/* Forward declarations of structures. */
-typedef struct fts3Hash fts3Hash;
-typedef struct fts3HashElem fts3HashElem;
-
-/* A complete hash table is an instance of the following structure.
-** The internals of this structure are intended to be opaque -- client
-** code should not attempt to access or modify the fields of this structure
-** directly.  Change this structure only by using the routines below.
-** However, many of the "procedures" and "functions" for modifying and
-** accessing this structure are really macros, so we can't really make
-** this structure opaque.
-*/
-struct fts3Hash {
-  char keyClass;          /* HASH_INT, _POINTER, _STRING, _BINARY */
-  char copyKey;           /* True if copy of key made on insert */
-  int count;              /* Number of entries in this table */
-  fts3HashElem *first;    /* The first element of the array */
-  int htsize;             /* Number of buckets in the hash table */
-  struct _fts3ht {        /* the hash table */
-    int count;               /* Number of entries with this hash */
-    fts3HashElem *chain;     /* Pointer to first entry with this hash */
-  } *ht;
-};
-
-/* Each element in the hash table is an instance of the following
-** structure.  All elements are stored on a single doubly-linked list.
-**
-** Again, this structure is intended to be opaque, but it can't really
-** be opaque because it is used by macros.
-*/
-struct fts3HashElem {
-  fts3HashElem *next, *prev; /* Next and previous elements in the table */
-  void *data;                /* Data associated with this element */
-  void *pKey; int nKey;      /* Key associated with this element */
-};
-
-/*
-** There are 2 different modes of operation for a hash table:
-**
-**   FTS3_HASH_STRING        pKey points to a string that is nKey bytes long
-**                           (including the null-terminator, if any).  Case
-**                           is respected in comparisons.
-**
-**   FTS3_HASH_BINARY        pKey points to binary data nKey bytes long.
-**                           memcmp() is used to compare keys.
-**
-** A copy of the key is made if the copyKey parameter to fts3HashInit is 1.
-*/
-#define FTS3_HASH_STRING    1
-#define FTS3_HASH_BINARY    2
-
-/*
-** Access routines.  To delete, insert a NULL pointer.
-*/
-SQLITE_PRIVATE void sqlite3Fts3HashInit(fts3Hash*, int keytype, int copyKey);
-SQLITE_PRIVATE void *sqlite3Fts3HashInsert(fts3Hash*, const void *pKey, int nKey, void *pData);
-SQLITE_PRIVATE void *sqlite3Fts3HashFind(const fts3Hash*, const void *pKey, int nKey);
-SQLITE_PRIVATE void sqlite3Fts3HashClear(fts3Hash*);
-
-/*
-** Shorthand for the functions above
-*/
-#define fts3HashInit   sqlite3Fts3HashInit
-#define fts3HashInsert sqlite3Fts3HashInsert
-#define fts3HashFind   sqlite3Fts3HashFind
-#define fts3HashClear  sqlite3Fts3HashClear
-
-/*
-** Macros for looping over all elements of a hash table.  The idiom is
-** like this:
-**
-**   fts3Hash h;
-**   fts3HashElem *p;
-**   ...
-**   for(p=fts3HashFirst(&h); p; p=fts3HashNext(p)){
-**     SomeStructure *pData = fts3HashData(p);
-**     // do something with pData
-**   }
-*/
-#define fts3HashFirst(H)  ((H)->first)
-#define fts3HashNext(E)   ((E)->next)
-#define fts3HashData(E)   ((E)->data)
-#define fts3HashKey(E)    ((E)->pKey)
-#define fts3HashKeysize(E) ((E)->nKey)
-
-/*
-** Number of entries in a hash table
-*/
-#define fts3HashCount(H)  ((H)->count)
-
-#endif /* _FTS3_HASH_H_ */
-
-/************** End of fts3_hash.h *******************************************/
-/************** Continuing where we left off in fts3.c ***********************/
+#include "fts3Int.h"
+
+
 #ifndef SQLITE_CORE
   SQLITE_EXTENSION_INIT1
 #endif
+
 
 
 /* TODO(shess) MAN, this thing needs some refactoring.  At minimum, it
 ** would be nice to order the file better, perhaps something along the
 ** lines of:
@@ -98005,29 +97798,10 @@
 #if 0
 # define FTSTRACE(A)  printf A; fflush(stdout)
 #else
 # define FTSTRACE(A)
 #endif
-
-/* It is not safe to call isspace(), tolower(), or isalnum() on
-** hi-bit-set characters.  This is the same solution used in the
-** tokenizer.
-*/
-/* TODO(shess) The snippet-generation code should be using the
-** tokenizer-generated tokens rather than doing its own local
-** tokenization.
-*/
-/* TODO(shess) Is __isascii() a portable version of (c&0x80)==0? */
-static int safe_isspace(char c){
-  return (c&0x80)==0 ? isspace(c) : 0;
-}
-static int safe_tolower(char c){
-  return (c&0x80)==0 ? tolower(c) : c;
-}
-static int safe_isalnum(char c){
-  return (c&0x80)==0 ? isalnum(c) : 0;
-}
 
 typedef enum DocListType {
   DL_DOCIDS,              /* docids only */
   DL_POSITIONS,           /* docids + positions */
   DL_POSITIONS_OFFSETS    /* docids + positions + offsets */
@@ -98050,15 +97824,10 @@
   POS_END = 0,        /* end of this position list */
   POS_COLUMN,         /* followed by new column number */
   POS_BASE
 };
 
-/* MERGE_COUNT controls how often we merge segments (see comment at
-** top of file).
-*/
-#define MERGE_COUNT 16
-
 /* utility functions */
 
 /* CLEAR() and SCRAMBLE() abstract memset() on a pointer to a single
 ** record to prevent errors of the form:
 **
@@ -98073,7006 +97842,2268 @@
 #  define SCRAMBLE(b) memset(b, 0x55, sizeof(*(b)))
 #else
 #  define SCRAMBLE(b)
 #endif
 
-/* We may need up to VARINT_MAX bytes to store an encoded 64-bit integer. */
-#define VARINT_MAX 10
-
-/* Write a 64-bit variable-length integer to memory starting at p[0].
- * The length of data written will be between 1 and VARINT_MAX bytes.
- * The number of bytes written is returned. */
-static int fts3PutVarint(char *p, sqlite_int64 v){
+/*
+** Write a 64-bit variable-length integer to memory starting at p[0].
+** The length of data written will be between 1 and FTS3_VARINT_MAX bytes.
+** The number of bytes written is returned.
+*/
+SQLITE_PRIVATE int sqlite3Fts3PutVarint(char *p, sqlite_int64 v){
   unsigned char *q = (unsigned char *) p;
   sqlite_uint64 vu = v;
   do{
     *q++ = (unsigned char) ((vu & 0x7f) | 0x80);
     vu >>= 7;
   }while( vu!=0 );
   q[-1] &= 0x7f;  /* turn off high bit in final byte */
-  assert( q - (unsigned char *)p <= VARINT_MAX );
+  assert( q - (unsigned char *)p <= FTS3_VARINT_MAX );
   return (int) (q - (unsigned char *)p);
 }
 
-/* Read a 64-bit variable-length integer from memory starting at p[0].
- * Return the number of bytes read, or 0 on error.
- * The value is stored in *v. */
-static int fts3GetVarint(const char *p, sqlite_int64 *v){
+/*
+** Read a 64-bit variable-length integer from memory starting at p[0].
+** Return the number of bytes read, or 0 on error.
+** The value is stored in *v.
+*/
+SQLITE_PRIVATE int sqlite3Fts3GetVarint(const char *p, sqlite_int64 *v){
   const unsigned char *q = (const unsigned char *) p;
   sqlite_uint64 x = 0, y = 1;
   while( (*q & 0x80) == 0x80 ){
     x += y * (*q++ & 0x7f);
     y <<= 7;
-    if( q - (unsigned char *)p >= VARINT_MAX ){  /* bad data */
+    if( q - (unsigned char *)p >= FTS3_VARINT_MAX ){  /* bad data */
       assert( 0 );
       return 0;
     }
   }
   x += y * (*q++);
   *v = (sqlite_int64) x;
   return (int) (q - (unsigned char *)p);
 }
 
-static int fts3GetVarint32(const char *p, int *pi){
+/*
+** Similar to sqlite3Fts3GetVarint(), except that the output is truncated to a
+** 32-bit integer before it is returned.
+*/
+SQLITE_PRIVATE int sqlite3Fts3GetVarint32(const char *p, int *pi){
  sqlite_int64 i;
- int ret = fts3GetVarint(p, &i);
+ int ret = sqlite3Fts3GetVarint(p, &i);
  *pi = (int) i;
  assert( *pi==i );
  return ret;
 }
 
-/*******************************************************************/
-/* DataBuffer is used to collect data into a buffer in piecemeal
-** fashion.  It implements the usual distinction between amount of
-** data currently stored (nData) and buffer capacity (nCapacity).
-**
-** dataBufferInit - create a buffer with given initial capacity.
-** dataBufferReset - forget buffer's data, retaining capacity.
-** dataBufferDestroy - free buffer's data.
-** dataBufferSwap - swap contents of two buffers.
-** dataBufferExpand - expand capacity without adding data.
-** dataBufferAppend - append data.
-** dataBufferAppend2 - append two pieces of data at once.
-** dataBufferReplace - replace buffer's data.
-*/
-typedef struct DataBuffer {
-  char *pData;          /* Pointer to malloc'ed buffer. */
-  int nCapacity;        /* Size of pData buffer. */
-  int nData;            /* End of data loaded into pData. */
-} DataBuffer;
-
-static void dataBufferInit(DataBuffer *pBuffer, int nCapacity){
-  assert( nCapacity>=0 );
-  pBuffer->nData = 0;
-  pBuffer->nCapacity = nCapacity;
-  pBuffer->pData = nCapacity==0 ? NULL : sqlite3_malloc(nCapacity);
-}
-static void dataBufferReset(DataBuffer *pBuffer){
-  pBuffer->nData = 0;
-}
-static void dataBufferDestroy(DataBuffer *pBuffer){
-  if( pBuffer->pData!=NULL ) sqlite3_free(pBuffer->pData);
-  SCRAMBLE(pBuffer);
-}
-static void dataBufferSwap(DataBuffer *pBuffer1, DataBuffer *pBuffer2){
-  DataBuffer tmp = *pBuffer1;
-  *pBuffer1 = *pBuffer2;
-  *pBuffer2 = tmp;
-}
-static void dataBufferExpand(DataBuffer *pBuffer, int nAddCapacity){
-  assert( nAddCapacity>0 );
-  /* TODO(shess) Consider expanding more aggressively.  Note that the
-  ** underlying malloc implementation may take care of such things for
-  ** us already.
-  */
-  if( pBuffer->nData+nAddCapacity>pBuffer->nCapacity ){
-    pBuffer->nCapacity = pBuffer->nData+nAddCapacity;
-    pBuffer->pData = sqlite3_realloc(pBuffer->pData, pBuffer->nCapacity);
-  }
-}
-static void dataBufferAppend(DataBuffer *pBuffer,
-                             const char *pSource, int nSource){
-  assert( nSource>0 && pSource!=NULL );
-  dataBufferExpand(pBuffer, nSource);
-  memcpy(pBuffer->pData+pBuffer->nData, pSource, nSource);
-  pBuffer->nData += nSource;
-}
-static void dataBufferAppend2(DataBuffer *pBuffer,
-                              const char *pSource1, int nSource1,
-                              const char *pSource2, int nSource2){
-  assert( nSource1>0 && pSource1!=NULL );
-  assert( nSource2>0 && pSource2!=NULL );
-  dataBufferExpand(pBuffer, nSource1+nSource2);
-  memcpy(pBuffer->pData+pBuffer->nData, pSource1, nSource1);
-  memcpy(pBuffer->pData+pBuffer->nData+nSource1, pSource2, nSource2);
-  pBuffer->nData += nSource1+nSource2;
-}
-static void dataBufferReplace(DataBuffer *pBuffer,
-                              const char *pSource, int nSource){
-  dataBufferReset(pBuffer);
-  dataBufferAppend(pBuffer, pSource, nSource);
-}
-
-/* StringBuffer is a null-terminated version of DataBuffer. */
-typedef struct StringBuffer {
-  DataBuffer b;            /* Includes null terminator. */
-} StringBuffer;
-
-static void initStringBuffer(StringBuffer *sb){
-  dataBufferInit(&sb->b, 100);
-  dataBufferReplace(&sb->b, "", 1);
-}
-static int stringBufferLength(StringBuffer *sb){
-  return sb->b.nData-1;
-}
-static char *stringBufferData(StringBuffer *sb){
-  return sb->b.pData;
-}
-static void stringBufferDestroy(StringBuffer *sb){
-  dataBufferDestroy(&sb->b);
-}
-
-static void nappend(StringBuffer *sb, const char *zFrom, int nFrom){
-  assert( sb->b.nData>0 );
-  if( nFrom>0 ){
-    sb->b.nData--;
-    dataBufferAppend2(&sb->b, zFrom, nFrom, "", 1);
-  }
-}
-static void append(StringBuffer *sb, const char *zFrom){
-  nappend(sb, zFrom, strlen(zFrom));
-}
-
-/* Append a list of strings separated by commas. */
-static void appendList(StringBuffer *sb, int nString, char **azString){
+/*
+** Return the number of bytes required to store the value passed as the
+** first argument in varint form.
+*/
+SQLITE_PRIVATE int sqlite3Fts3VarintLen(sqlite3_uint64 v){
+  int i = 0;
+  do{
+    i++;
+    v >>= 7;
+  }while( v!=0 );
+  return i;
+}
+
+/*
+** Convert an SQL-style quoted string into a normal string by removing
+** the quote characters.  The conversion is done in-place.  If the
+** input does not begin with a quote character, then this routine
+** is a no-op.
+**
+** Examples:
+**
+**     "abc"   becomes   abc
+**     'xyz'   becomes   xyz
+**     [pqr]   becomes   pqr
+**     `mno`   becomes   mno
+*/
+SQLITE_PRIVATE void sqlite3Fts3Dequote(char *z){
+  int quote;
+  int i, j;
+
+  quote = z[0];
+  switch( quote ){
+    case '\'':  break;
+    case '"':   break;
+    case '`':   break;                /* For MySQL compatibility */
+    case '[':   quote = ']';  break;  /* For MS SqlServer compatibility */
+    default:    return;
+  }
+  for(i=1, j=0; z[i]; i++){
+    if( z[i]==quote ){
+      if( z[i+1]==quote ){
+        z[j++] = quote;
+        i++;
+      }else{
+        z[j++] = 0;
+        break;
+      }
+    }else{
+      z[j++] = z[i];
+    }
+  }
+}
+
+static void fts3GetDeltaVarint(char **pp, sqlite3_int64 *pVal){
+  sqlite3_int64 iVal;
+  *pp += sqlite3Fts3GetVarint(*pp, &iVal);
+  *pVal += iVal;
+}
+
+static void fts3GetDeltaVarint2(char **pp, char *pEnd, sqlite3_int64 *pVal){
+  if( *pp>=pEnd ){
+    *pp = 0;
+  }else{
+    fts3GetDeltaVarint(pp, pVal);
+  }
+}
+
+
+/*
+** The Fts3Cursor.eType member is always set to one of the following.
+*/
+#define FTS3_FULLSCAN_SEARCH 0    /* Linear scan of %_content table */
+#define FTS3_DOCID_SEARCH    1    /* Lookup by rowid on %_content table */
+#define FTS3_FULLTEXT_SEARCH 2    /* Full-text index search */
+
+static Fts3Table *cursor_vtab(Fts3Cursor *c){
+  return (Fts3Table *) c->base.pVtab;
+}
+
+/*
+** The xDisconnect() virtual table method.
+*/
+static int fts3DisconnectMethod(sqlite3_vtab *pVtab){
+  Fts3Table *p = (Fts3Table *)pVtab;
+  int i;
+
+  assert( p->nPendingData==0 );
+
+  /* Free any prepared statements held */
+  for(i=0; i<SizeofArray(p->aStmt); i++){
+    sqlite3_finalize(p->aStmt[i]);
+  }
+  for(i=0; i<p->nLeavesStmt; i++){
+    sqlite3_finalize(p->aLeavesStmt[i]);
+  }
+  sqlite3_free(p->zSelectLeaves);
+  sqlite3_free(p->aLeavesStmt);
+
+  /* Invoke the tokenizer destructor to free the tokenizer. */
+  p->pTokenizer->pModule->xDestroy(p->pTokenizer);
+
+  sqlite3_free(p);
+  return SQLITE_OK;
+}
+
+/*
+** The xDestroy() virtual table method.
+*/
+static int fts3DestroyMethod(sqlite3_vtab *pVtab){
+  int rc;                         /* Return code */
+  Fts3Table *p = (Fts3Table *)pVtab;
+
+  /* Create a script to drop the underlying three storage tables. */
+  char *zSql = sqlite3_mprintf(
+      "DROP TABLE IF EXISTS %Q.'%q_content';"
+      "DROP TABLE IF EXISTS %Q.'%q_segments';"
+      "DROP TABLE IF EXISTS %Q.'%q_segdir';",
+      p->zDb, p->zName, p->zDb, p->zName, p->zDb, p->zName
+  );
+
+  /* If malloc has failed, set rc to SQLITE_NOMEM. Otherwise, try to
+  ** execute the SQL script created above.
+  */
+  if( zSql ){
+    rc = sqlite3_exec(p->db, zSql, 0, 0, 0);
+    sqlite3_free(zSql);
+  }else{
+    rc = SQLITE_NOMEM;
+  }
+
+  /* If everything has worked, invoke fts3DisconnectMethod() to free the
+  ** memory associated with the Fts3Table structure and return SQLITE_OK.
+  ** Otherwise, return an SQLite error code.
+  */
+  return (rc==SQLITE_OK ? fts3DisconnectMethod(pVtab) : rc);
+}
+
+
+/*
+** Invoke sqlite3_declare_vtab() to declare the schema for the FTS3 table
+** passed as the first argument. This is done as part of the xConnect()
+** and xCreate() methods.
+*/
+static int fts3DeclareVtab(Fts3Table *p){
+  int i;                          /* Iterator variable */
+  int rc;                         /* Return code */
+  char *zSql;                     /* SQL statement passed to declare_vtab() */
+  char *zCols;                    /* List of user defined columns */
+
+  /* Create a list of user columns for the virtual table */
+  zCols = sqlite3_mprintf("%Q, ", p->azColumn[0]);
+  for(i=1; zCols && i<p->nColumn; i++){
+    zCols = sqlite3_mprintf("%z%Q, ", zCols, p->azColumn[i]);
+  }
+
+  /* Create the whole "CREATE TABLE" statement to pass to SQLite */
+  zSql = sqlite3_mprintf(
+      "CREATE TABLE x(%s %Q HIDDEN, docid HIDDEN)", zCols, p->zName
+  );
+
+  if( !zCols || !zSql ){
+    rc = SQLITE_NOMEM;
+  }else{
+    rc = sqlite3_declare_vtab(p->db, zSql);
+  }
+
+  sqlite3_free(zSql);
+  sqlite3_free(zCols);
+  return rc;
+}
+
+/*
+** Create the backing store tables (%_content, %_segments and %_segdir)
+** required by the FTS3 table passed as the only argument. This is done
+** as part of the vtab xCreate() method.
+*/
+static int fts3CreateTables(Fts3Table *p){
+  int rc;                         /* Return code */
+  int i;                          /* Iterator variable */
+  char *zContentCols;             /* Columns of %_content table */
+  char *zSql;                     /* SQL script to create required tables */
+
+  /* Create a list of user columns for the content table */
+  zContentCols = sqlite3_mprintf("docid INTEGER PRIMARY KEY");
+  for(i=0; zContentCols && i<p->nColumn; i++){
+    char *z = p->azColumn[i];
+    zContentCols = sqlite3_mprintf("%z, 'c%d%q'", zContentCols, i, z);
+  }
+
+  /* Create the whole SQL script */
+  zSql = sqlite3_mprintf(
+      "CREATE TABLE %Q.'%q_content'(%s);"
+      "CREATE TABLE %Q.'%q_segments'(blockid INTEGER PRIMARY KEY, block BLOB);"
+      "CREATE TABLE %Q.'%q_segdir'("
+        "level INTEGER,"
+        "idx INTEGER,"
+        "start_block INTEGER,"
+        "leaves_end_block INTEGER,"
+        "end_block INTEGER,"
+        "root BLOB,"
+        "PRIMARY KEY(level, idx)"
+      ");",
+      p->zDb, p->zName, zContentCols, p->zDb, p->zName, p->zDb, p->zName
+  );
+
+  /* Unless a malloc() failure has occurred, execute the SQL script to
+  ** create the tables used to store data for this FTS3 virtual table.
+  */
+  if( zContentCols==0 || zSql==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    rc = sqlite3_exec(p->db, zSql, 0, 0, 0);
+  }
+
+  sqlite3_free(zSql);
+  sqlite3_free(zContentCols);
+  return rc;
+}
+
+/*
+** This function is the implementation of both the xConnect and xCreate
+** methods of the FTS3 virtual table.
+**
+** The argv[] array contains the following:
+**
+**   argv[0]   -> module name
+**   argv[1]   -> database name
+**   argv[2]   -> table name
+**   argv[...] -> "column name" fields...
+*/
+int fts3InitVtab(
+  int isCreate,                   /* True for xCreate, false for xConnect */
+  sqlite3 *db,                    /* The SQLite database connection */
+  void *pAux,                     /* Hash table containing tokenizers */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVTab,          /* Write the resulting vtab structure here */
+  char **pzErr                    /* Write any error message here */
+){
+  Fts3Hash *pHash = (Fts3Hash *)pAux;
+  Fts3Table *p;               /* Pointer to allocated vtab */
+  int rc;                         /* Return code */
   int i;
-  for(i=0; i<nString; ++i){
-    if( i>0 ) append(sb, ", ");
-    append(sb, azString[i]);
-  }
-}
-
-static int endsInWhiteSpace(StringBuffer *p){
-  return stringBufferLength(p)>0 &&
-    safe_isspace(stringBufferData(p)[stringBufferLength(p)-1]);
-}
-
-/* If the StringBuffer ends in something other than white space, add a
-** single space character to the end.
-*/
-static void appendWhiteSpace(StringBuffer *p){
-  if( stringBufferLength(p)==0 ) return;
-  if( !endsInWhiteSpace(p) ) append(p, " ");
-}
-
-/* Remove white space from the end of the StringBuffer */
-static void trimWhiteSpace(StringBuffer *p){
-  while( endsInWhiteSpace(p) ){
-    p->b.pData[--p->b.nData-1] = '\0';
-  }
-}
-
-/*******************************************************************/
-/* DLReader is used to read document elements from a doclist.  The
-** current docid is cached, so dlrDocid() is fast.  DLReader does not
-** own the doclist buffer.
-**
-** dlrAtEnd - true if there's no more data to read.
-** dlrDocid - docid of current document.
-** dlrDocData - doclist data for current document (including docid).
-** dlrDocDataBytes - length of same.
-** dlrAllDataBytes - length of all remaining data.
-** dlrPosData - position data for current document.
-** dlrPosDataLen - length of pos data for current document (incl POS_END).
-** dlrStep - step to current document.
-** dlrInit - initial for doclist of given type against given data.
-** dlrDestroy - clean up.
-**
-** Expected usage is something like:
-**
-**   DLReader reader;
-**   dlrInit(&reader, pData, nData);
-**   while( !dlrAtEnd(&reader) ){
-**     // calls to dlrDocid() and kin.
-**     dlrStep(&reader);
-**   }
-**   dlrDestroy(&reader);
-*/
-typedef struct DLReader {
-  DocListType iType;
-  const char *pData;
-  int nData;
-
-  sqlite_int64 iDocid;
-  int nElement;
-} DLReader;
-
-static int dlrAtEnd(DLReader *pReader){
-  assert( pReader->nData>=0 );
-  return pReader->nData==0;
-}
-static sqlite_int64 dlrDocid(DLReader *pReader){
-  assert( !dlrAtEnd(pReader) );
-  return pReader->iDocid;
-}
-static const char *dlrDocData(DLReader *pReader){
-  assert( !dlrAtEnd(pReader) );
-  return pReader->pData;
-}
-static int dlrDocDataBytes(DLReader *pReader){
-  assert( !dlrAtEnd(pReader) );
-  return pReader->nElement;
-}
-static int dlrAllDataBytes(DLReader *pReader){
-  assert( !dlrAtEnd(pReader) );
-  return pReader->nData;
-}
-/* TODO(shess) Consider adding a field to track iDocid varint length
-** to make these two functions faster.  This might matter (a tiny bit)
-** for queries.
-*/
-static const char *dlrPosData(DLReader *pReader){
-  sqlite_int64 iDummy;
-  int n = fts3GetVarint(pReader->pData, &iDummy);
-  assert( !dlrAtEnd(pReader) );
-  return pReader->pData+n;
-}
-static int dlrPosDataLen(DLReader *pReader){
-  sqlite_int64 iDummy;
-  int n = fts3GetVarint(pReader->pData, &iDummy);
-  assert( !dlrAtEnd(pReader) );
-  return pReader->nElement-n;
-}
-static void dlrStep(DLReader *pReader){
-  assert( !dlrAtEnd(pReader) );
-
-  /* Skip past current doclist element. */
-  assert( pReader->nElement<=pReader->nData );
-  pReader->pData += pReader->nElement;
-  pReader->nData -= pReader->nElement;
-
-  /* If there is more data, read the next doclist element. */
-  if( pReader->nData!=0 ){
-    sqlite_int64 iDocidDelta;
-    int iDummy, n = fts3GetVarint(pReader->pData, &iDocidDelta);
-    pReader->iDocid += iDocidDelta;
-    if( pReader->iType>=DL_POSITIONS ){
-      assert( n<pReader->nData );
-      while( 1 ){
-        n += fts3GetVarint32(pReader->pData+n, &iDummy);
-        assert( n<=pReader->nData );
-        if( iDummy==POS_END ) break;
-        if( iDummy==POS_COLUMN ){
-          n += fts3GetVarint32(pReader->pData+n, &iDummy);
-          assert( n<pReader->nData );
-        }else if( pReader->iType==DL_POSITIONS_OFFSETS ){
-          n += fts3GetVarint32(pReader->pData+n, &iDummy);
-          n += fts3GetVarint32(pReader->pData+n, &iDummy);
-          assert( n<pReader->nData );
-        }
-      }
-    }
-    pReader->nElement = n;
-    assert( pReader->nElement<=pReader->nData );
-  }
-}
-static void dlrInit(DLReader *pReader, DocListType iType,
-                    const char *pData, int nData){
-  assert( pData!=NULL && nData!=0 );
-  pReader->iType = iType;
-  pReader->pData = pData;
-  pReader->nData = nData;
-  pReader->nElement = 0;
-  pReader->iDocid = 0;
-
-  /* Load the first element's data.  There must be a first element. */
-  dlrStep(pReader);
-}
-static void dlrDestroy(DLReader *pReader){
-  SCRAMBLE(pReader);
-}
-
-#ifndef NDEBUG
-/* Verify that the doclist can be validly decoded.  Also returns the
-** last docid found because it is convenient in other assertions for
-** DLWriter.
-*/
-static void docListValidate(DocListType iType, const char *pData, int nData,
-                            sqlite_int64 *pLastDocid){
-  sqlite_int64 iPrevDocid = 0;
-  assert( nData>0 );
-  assert( pData!=0 );
-  assert( pData+nData>pData );
-  while( nData!=0 ){
-    sqlite_int64 iDocidDelta;
-    int n = fts3GetVarint(pData, &iDocidDelta);
-    iPrevDocid += iDocidDelta;
-    if( iType>DL_DOCIDS ){
-      int iDummy;
+  int nByte;
+  int iCol;
+  int nString = 0;
+  int nCol = 0;
+  char *zCsr;
+  int nDb;
+  int nName;
+
+  const char *zTokenizer = 0;
+  sqlite3_tokenizer *pTokenizer;  /* Tokenizer for this table */
+
+  nDb = strlen(argv[1]) + 1;
+  nName = strlen(argv[2]) + 1;
+  for(i=3; i<argc; i++){
+    char const *z = argv[i];
+    rc = sqlite3Fts3InitTokenizer(pHash, z, &pTokenizer, &zTokenizer, pzErr);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    if( z!=zTokenizer ){
+      nString += strlen(z) + 1;
+    }
+  }
+  nCol = argc - 3 - (zTokenizer!=0);
+  if( zTokenizer==0 ){
+    rc = sqlite3Fts3InitTokenizer(pHash, 0, &pTokenizer, 0, pzErr);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    assert( pTokenizer );
+  }
+
+  /* Allocate and populate the Fts3Table structure. */
+  nByte = sizeof(Fts3Table) +              /* Fts3Table */
+          nCol * sizeof(char *) +              /* azColumn */
+          nName +                              /* zName */
+          nDb +                                /* zDb */
+          nString;                             /* Space for azColumn strings */
+  p = (Fts3Table*)sqlite3_malloc(nByte);
+  if( p==0 ){
+    rc = SQLITE_NOMEM;
+    goto fts3_init_out;
+  }
+  memset(p, 0, nByte);
+
+  p->db = db;
+  p->nColumn = nCol;
+  p->nPendingData = 0;
+  p->azColumn = (char **)&p[1];
+  p->pTokenizer = pTokenizer;
+  zCsr = (char *)&p->azColumn[nCol];
+
+  fts3HashInit(&p->pendingTerms, FTS3_HASH_STRING, 1);
+
+  /* Fill in the zName and zDb fields of the vtab structure. */
+  p->zName = zCsr;
+  memcpy(zCsr, argv[2], nName);
+  zCsr += nName;
+  p->zDb = zCsr;
+  memcpy(zCsr, argv[1], nDb);
+  zCsr += nDb;
+
+  /* Fill in the azColumn array */
+  iCol = 0;
+  for(i=3; i<argc; i++){
+    if( argv[i]!=zTokenizer ){
+      char *z;
+      int n;
+      z = (char *)sqlite3Fts3NextToken(argv[i], &n);
+      memcpy(zCsr, z, n);
+      zCsr[n] = '\0';
+      sqlite3Fts3Dequote(zCsr);
+      p->azColumn[iCol++] = zCsr;
+      zCsr += n+1;
+      assert( zCsr <= &((char *)p)[nByte] );
+    }
+  }
+
+  /* If this is an xCreate call, create the underlying tables in the
+  ** database. TODO: For xConnect(), it could verify that said tables exist.
+  */
+  if( isCreate ){
+    rc = fts3CreateTables(p);
+    if( rc!=SQLITE_OK ) goto fts3_init_out;
+  }
+
+  rc = fts3DeclareVtab(p);
+  if( rc!=SQLITE_OK ) goto fts3_init_out;
+
+  *ppVTab = &p->base;
+
+fts3_init_out:
+  if( rc!=SQLITE_OK ){
+    if( p ) fts3DisconnectMethod((sqlite3_vtab *)p);
+    else if( pTokenizer ) pTokenizer->pModule->xDestroy(pTokenizer);
+  }
+  return rc;
+}
+
+/*
+** The xConnect() and xCreate() methods for the virtual table. All the
+** work is done in function fts3InitVtab().
+*/
+static int fts3ConnectMethod(
+  sqlite3 *db,                    /* Database connection */
+  void *pAux,                     /* Pointer to tokenizer hash table */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
+  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
+){
+  return fts3InitVtab(0, db, pAux, argc, argv, ppVtab, pzErr);
+}
+static int fts3CreateMethod(
+  sqlite3 *db,                    /* Database connection */
+  void *pAux,                     /* Pointer to tokenizer hash table */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
+  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
+){
+  return fts3InitVtab(1, db, pAux, argc, argv, ppVtab, pzErr);
+}
+
+/*
+** Implementation of the xBestIndex method for FTS3 tables. There
+** are three possible strategies, in order of preference:
+**
+**   1. Direct lookup by rowid or docid.
+**   2. Full-text search using a MATCH operator on a non-docid column.
+**   3. Linear scan of %_content table.
+*/
+static int fts3BestIndexMethod(sqlite3_vtab *pVTab, sqlite3_index_info *pInfo){
+  Fts3Table *p = (Fts3Table *)pVTab;
+  int i;                          /* Iterator variable */
+  int iCons = -1;                 /* Index of constraint to use */
+
+  /* By default use a full table scan. This is an expensive option,
+  ** so search through the constraints to see if a more efficient
+  ** strategy is possible.
+  */
+  pInfo->idxNum = FTS3_FULLSCAN_SEARCH;
+  pInfo->estimatedCost = 500000;
+  for(i=0; i<pInfo->nConstraint; i++){
+    struct sqlite3_index_constraint *pCons = &pInfo->aConstraint[i];
+    if( pCons->usable==0 ) continue;
+
+    /* A direct lookup on the rowid or docid column. This is the best
+    ** strategy in all cases. Assign a cost of 1.0 and return early.
+    */
+    if( pCons->op==SQLITE_INDEX_CONSTRAINT_EQ
+     && (pCons->iColumn<0 || pCons->iColumn==p->nColumn+1 )
+    ){
+      pInfo->idxNum = FTS3_DOCID_SEARCH;
+      pInfo->estimatedCost = 1.0;
+      iCons = i;
+      break;
+    }
+
+    /* A MATCH constraint. Use a full-text search.
+    **
+    ** If there is more than one MATCH constraint available, use the first
+    ** one encountered. If there is both a MATCH constraint and a direct
+    ** rowid/docid lookup, prefer the rowid/docid strategy.
+    */
+    if( iCons<0
+     && pCons->op==SQLITE_INDEX_CONSTRAINT_MATCH
+     && pCons->iColumn>=0 && pCons->iColumn<=p->nColumn
+    ){
+      pInfo->idxNum = FTS3_FULLTEXT_SEARCH + pCons->iColumn;
+      pInfo->estimatedCost = 2.0;
+      iCons = i;
+    }
+  }
+
+  if( iCons>=0 ){
+    pInfo->aConstraintUsage[iCons].argvIndex = 1;
+    pInfo->aConstraintUsage[iCons].omit = 1;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Implementation of xOpen method.
+*/
+static int fts3OpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
+  sqlite3_vtab_cursor *pCsr;               /* Allocated cursor */
+
+  /* Allocate a buffer large enough for an Fts3Cursor structure. If the
+  ** allocation succeeds, zero it and return SQLITE_OK. Otherwise,
+  ** if the allocation fails, return SQLITE_NOMEM.
+  */
+  *ppCsr = pCsr = (sqlite3_vtab_cursor *)sqlite3_malloc(sizeof(Fts3Cursor));
+  if( !pCsr ){
+    return SQLITE_NOMEM;
+  }
+  memset(pCsr, 0, sizeof(Fts3Cursor));
+  return SQLITE_OK;
+}
+
+/****************************************************************/
+/****************************************************************/
+/****************************************************************/
+/****************************************************************/
+
+
+/*
+** Close the cursor.  For additional information see the documentation
+** on the xClose method of the virtual table interface.
+*/
+static int fulltextClose(sqlite3_vtab_cursor *pCursor){
+  Fts3Cursor *pCsr = (Fts3Cursor *)pCursor;
+  sqlite3_finalize(pCsr->pStmt);
+  sqlite3Fts3ExprFree(pCsr->pExpr);
+  sqlite3_free(pCsr->aDoclist);
+  sqlite3_free(pCsr);
+  return SQLITE_OK;
+}
+
+static int fts3CursorSeek(Fts3Cursor *pCsr){
+  if( pCsr->isRequireSeek ){
+    pCsr->isRequireSeek = 0;
+    sqlite3_bind_int64(pCsr->pStmt, 1, pCsr->iPrevId);
+    if( SQLITE_ROW==sqlite3_step(pCsr->pStmt) ){
+      return SQLITE_OK;
+    }else{
+      int rc;
+      pCsr->isEof = 1;
+      if( SQLITE_OK==(rc = sqlite3_reset(pCsr->pStmt)) ){
+        rc = SQLITE_ERROR;
+      }
+      return rc;
+    }
+  }else{
+    return SQLITE_OK;
+  }
+}
+
+static int fts3NextMethod(sqlite3_vtab_cursor *pCursor){
+  int rc = SQLITE_OK;             /* Return code */
+  Fts3Cursor *pCsr = (Fts3Cursor *)pCursor;
+
+  if( pCsr->aDoclist==0 ){
+    if( SQLITE_ROW!=sqlite3_step(pCsr->pStmt) ){
+      pCsr->isEof = 1;
+      rc = sqlite3_reset(pCsr->pStmt);
+    }
+  }else if( pCsr->pNextId>=&pCsr->aDoclist[pCsr->nDoclist] ){
+    pCsr->isEof = 1;
+  }else{
+    sqlite3_reset(pCsr->pStmt);
+    fts3GetDeltaVarint(&pCsr->pNextId, &pCsr->iPrevId);
+    pCsr->isRequireSeek = 1;
+  }
+  return rc;
+}
+
+
+/*
+** The buffer pointed to by argument zNode (size nNode bytes) contains the
+** root node of a b-tree segment. The segment is guaranteed to be at least
+** one level high (i.e. the root node is not also a leaf). If successful,
+** this function locates the leaf node of the segment that may contain the
+** term specified by arguments zTerm and nTerm and writes its block number
+** to *piLeaf.
+**
+** It is possible that the returned leaf node does not contain the specified
+** term. However, if the segment does contain said term, it is stored on
+** the identified leaf node. Because this function only inspects interior
+** segment nodes (and never loads leaf nodes into memory), it is not possible
+** to be sure.
+**
+** If an error occurs, an error code other than SQLITE_OK is returned.
+*/
+static int fts3SelectLeaf(
+  Fts3Table *p,                   /* Virtual table handle */
+  const char *zTerm,              /* Term to select leaves for */
+  int nTerm,                      /* Size of term zTerm in bytes */
+  const char *zNode,              /* Buffer containing segment interior node */
+  int nNode,                      /* Size of buffer at zNode */
+  sqlite3_int64 *piLeaf           /* Selected leaf node */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  const char *zCsr = zNode;       /* Cursor to iterate through node */
+  const char *zEnd = &zCsr[nNode];/* End of interior node buffer */
+  char *zBuffer = 0;              /* Buffer to load terms into */
+  int nAlloc = 0;                 /* Size of allocated buffer */
+
+  while( 1 ){
+    int isFirstTerm = 1;          /* True when processing first term on page */
+    int iHeight;                  /* Height of this node in tree */
+    sqlite3_int64 iChild;         /* Block id of child node to descend to */
+    int nBlock;                   /* Size of child node in bytes */
+
+    zCsr += sqlite3Fts3GetVarint32(zCsr, &iHeight);
+    zCsr += sqlite3Fts3GetVarint(zCsr, &iChild);
+
+    while( zCsr<zEnd ){
+      int cmp;                    /* memcmp() result */
+      int nSuffix;                /* Size of term suffix */
+      int nPrefix = 0;            /* Size of term prefix */
+      int nBuffer;                /* Total term size */
+
+      /* Load the next term on the node into zBuffer */
+      if( !isFirstTerm ){
+        zCsr += sqlite3Fts3GetVarint32(zCsr, &nPrefix);
+      }
+      isFirstTerm = 0;
+      zCsr += sqlite3Fts3GetVarint32(zCsr, &nSuffix);
+      if( nPrefix+nSuffix>nAlloc ){
+        char *zNew;
+        nAlloc = (nPrefix+nSuffix) * 2;
+        zNew = (char *)sqlite3_realloc(zBuffer, nAlloc);
+        if( !zNew ){
+          sqlite3_free(zBuffer);
+          return SQLITE_NOMEM;
+        }
+        zBuffer = zNew;
+      }
+      memcpy(&zBuffer[nPrefix], zCsr, nSuffix);
+      nBuffer = nPrefix + nSuffix;
+      zCsr += nSuffix;
+
+      /* Compare the term we are searching for with the term just loaded from
+      ** the interior node. If the specified term is greater than or equal
+      ** to the term from the interior node, then all terms on the sub-tree
+      ** headed by node iChild are smaller than zTerm. No need to search
+      ** iChild.
+      **
+      ** If the interior node term is larger than the specified term, then
+      ** the tree headed by iChild may contain the specified term.
+      */
+      cmp = memcmp(zTerm, zBuffer, (nBuffer>nTerm ? nTerm : nBuffer));
+      if( cmp<0 || (cmp==0 && nBuffer>nTerm) ) break;
+      iChild++;
+    };
+
+    /* If (iHeight==1), the children of this interior node are leaves. The
+    ** specified term may be present on leaf node iChild.
+    */
+    if( iHeight==1 ){
+      *piLeaf = iChild;
+      break;
+    }
+
+    /* Descend to interior node iChild. */
+    rc = sqlite3Fts3ReadBlock(p, iChild, &zCsr, &nBlock);
+    if( rc!=SQLITE_OK ) break;
+    zEnd = &zCsr[nBlock];
+  }
+  sqlite3_free(zBuffer);
+  return rc;
+}
+
+static void fts3PutDeltaVarint(
+  char **pp,
+  sqlite3_int64 *piPrev,
+  sqlite3_int64 iVal
+){
+  assert( iVal-*piPrev > 0 );
+  *pp += sqlite3Fts3PutVarint(*pp, iVal-*piPrev);
+  *piPrev = iVal;
+}
+
+static void fts3PoslistCopy(char **pp, char **ppPoslist){
+  char *pEnd = *ppPoslist;
+  char c = 0;
+  while( *pEnd | c ) c = *pEnd++ & 0x80;
+  pEnd++;
+  if( pp ){
+    int n = pEnd - *ppPoslist;
+    char *p = *pp;
+    memcpy(p, *ppPoslist, n);
+    p += n;
+    *pp = p;
+  }
+  *ppPoslist = pEnd;
+}
+
+static void fts3ColumnlistCopy(char **pp, char **ppPoslist){
+  char *pEnd = *ppPoslist;
+  char c = 0;
+  while( 0xFE & (*pEnd | c) ) c = *pEnd++ & 0x80;
+  if( pp ){
+    int n = pEnd - *ppPoslist;
+    char *p = *pp;
+    memcpy(p, *ppPoslist, n);
+    p += n;
+    *pp = p;
+  }
+  *ppPoslist = pEnd;
+}
+
+/*
+**
+*/
+static void fts3PoslistMerge(
+  char **pp,                      /* Output buffer */
+  char **pp1,                     /* Left input list */
+  char **pp2                      /* Right input list */
+){
+  char *p = *pp;
+  char *p1 = *pp1;
+  char *p2 = *pp2;
+
+  while( *p1 && *p2 ){
+    int iCol1 = 0;
+    int iCol2 = 0;
+    if( *p1==0x01 ) sqlite3Fts3GetVarint32(&p1[1], &iCol1);
+    if( *p2==0x01 ) sqlite3Fts3GetVarint32(&p2[1], &iCol2);
+
+    if( iCol1==iCol2 ){
+      sqlite3_int64 i1 = 0;
+      sqlite3_int64 i2 = 0;
+      sqlite3_int64 iPrev = 0;
+      if( iCol1!=0 ){
+        int n;
+        *p++ = 0x01;
+        n = sqlite3Fts3PutVarint(p, iCol1);
+        p += n;
+        p1 += 1 + n;
+        p2 += 1 + n;
+      }
+      while( (*p1&0xFE) || (*p2&0xFE) ){
+        if( i1==i2 ){
+          fts3GetDeltaVarint(&p1, &i1); i1 -= 2;
+          fts3GetDeltaVarint(&p2, &i2); i2 -= 2;
+        }else if( i1<i2 ){
+          fts3GetDeltaVarint(&p1, &i1); i1 -= 2;
+        }else{
+          fts3GetDeltaVarint(&p2, &i2); i2 -= 2;
+        }
+        fts3PutDeltaVarint(&p, &iPrev, (i1<i2 ? i1 : i2) + 2); iPrev -= 2;
+        if( 0==(*p1&0xFE) ) i1 = 0x7FFFFFFF;
+        if( 0==(*p2&0xFE) ) i2 = 0x7FFFFFFF;
+      }
+    }else if( iCol1<iCol2 ){
+      fts3ColumnlistCopy(&p, &p1);
+    }else{
+      fts3ColumnlistCopy(&p, &p2);
+    }
+  }
+
+  *p++ = '\0';
+  *pp = p;
+  *pp1 = p1 + 1;
+  *pp2 = p2 + 1;
+}
+
+/*
+** nToken==1 searches for adjacent positions.
+*/
+static int fts3PoslistPhraseMerge(
+  char **pp,                      /* Output buffer */
+  int nToken,                     /* Maximum difference in token positions */
+  int isSaveLeft,                 /* Save the left position */
+  char **pp1,                     /* Left input list */
+  char **pp2                      /* Right input list */
+){
+  char *p = (pp ? *pp : 0);
+  char *p1 = *pp1;
+  char *p2 = *pp2;
+
+  int iCol1 = 0;
+  int iCol2 = 0;
+  assert( *p1!=0 && *p2!=0 );
+  if( *p1==0x01 ){
+    p1++;
+    p1 += sqlite3Fts3GetVarint32(p1, &iCol1);
+  }
+  if( *p2==0x01 ){
+    p2++;
+    p2 += sqlite3Fts3GetVarint32(p2, &iCol2);
+  }
+
+  while( 1 ){
+    if( iCol1==iCol2 ){
+      char *pSave = p;
+      sqlite3_int64 iPrev = 0;
+      sqlite3_int64 iPos1 = 0;
+      sqlite3_int64 iPos2 = 0;
+
+      if( pp && iCol1 ){
+        *p++ = 0x01;
+        p += sqlite3Fts3PutVarint(p, iCol1);
+      }
+
+      assert( *p1!=0x00 && *p2!=0x00 && *p1!=0x01 && *p2!=0x01 );
+      fts3GetDeltaVarint(&p1, &iPos1); iPos1 -= 2;
+      fts3GetDeltaVarint(&p2, &iPos2); iPos2 -= 2;
+
       while( 1 ){
-        n += fts3GetVarint32(pData+n, &iDummy);
-        if( iDummy==POS_END ) break;
-        if( iDummy==POS_COLUMN ){
-          n += fts3GetVarint32(pData+n, &iDummy);
-        }else if( iType>DL_POSITIONS ){
-          n += fts3GetVarint32(pData+n, &iDummy);
-          n += fts3GetVarint32(pData+n, &iDummy);
-        }
-        assert( n<=nData );
-      }
-    }
-    assert( n<=nData );
-    pData += n;
-    nData -= n;
-  }
-  if( pLastDocid ) *pLastDocid = iPrevDocid;
-}
-#define ASSERT_VALID_DOCLIST(i, p, n, o) docListValidate(i, p, n, o)
-#else
-#define ASSERT_VALID_DOCLIST(i, p, n, o) assert( 1 )
-#endif
-
-/*******************************************************************/
-/* DLWriter is used to write doclist data to a DataBuffer.  DLWriter
-** always appends to the buffer and does not own it.
-**
-** dlwInit - initialize to write a given type doclistto a buffer.
-** dlwDestroy - clear the writer's memory.  Does not free buffer.
-** dlwAppend - append raw doclist data to buffer.
-** dlwCopy - copy next doclist from reader to writer.
-** dlwAdd - construct doclist element and append to buffer.
-**    Only apply dlwAdd() to DL_DOCIDS doclists (else use PLWriter).
-*/
-typedef struct DLWriter {
-  DocListType iType;
-  DataBuffer *b;
-  sqlite_int64 iPrevDocid;
-#ifndef NDEBUG
-  int has_iPrevDocid;
-#endif
-} DLWriter;
-
-static void dlwInit(DLWriter *pWriter, DocListType iType, DataBuffer *b){
-  pWriter->b = b;
-  pWriter->iType = iType;
-  pWriter->iPrevDocid = 0;
-#ifndef NDEBUG
-  pWriter->has_iPrevDocid = 0;
-#endif
-}
-static void dlwDestroy(DLWriter *pWriter){
-  SCRAMBLE(pWriter);
-}
-/* iFirstDocid is the first docid in the doclist in pData.  It is
-** needed because pData may point within a larger doclist, in which
-** case the first item would be delta-encoded.
-**
-** iLastDocid is the final docid in the doclist in pData.  It is
-** needed to create the new iPrevDocid for future delta-encoding.  The
-** code could decode the passed doclist to recreate iLastDocid, but
-** the only current user (docListMerge) already has decoded this
+        if( iPos2>iPos1 && iPos2<=iPos1+nToken ){
+          sqlite3_int64 iSave;
+          if( !pp ){
+            fts3PoslistCopy(0, &p2);
+            fts3PoslistCopy(0, &p1);
+            *pp1 = p1;
+            *pp2 = p2;
+            return 1;
+          }
+          iSave = isSaveLeft ? iPos1 : iPos2;
+          fts3PutDeltaVarint(&p, &iPrev, iSave+2); iPrev -= 2;
+          pSave = 0;
+        }
+        if( iPos2<=iPos1 ){
+          if( (*p2&0xFE)==0 ) break;
+          fts3GetDeltaVarint(&p2, &iPos2); iPos2 -= 2;
+        }else{
+          if( (*p1&0xFE)==0 ) break;
+          fts3GetDeltaVarint(&p1, &iPos1); iPos1 -= 2;
+        }
+      }
+      if( pSave && pp ){
+        p = pSave;
+      }
+
+      fts3ColumnlistCopy(0, &p1);
+      fts3ColumnlistCopy(0, &p2);
+      assert( (*p1&0xFE)==0 && (*p2&0xFE)==0 );
+      if( 0==*p1 || 0==*p2 ) break;
+
+      p1++;
+      p1 += sqlite3Fts3GetVarint32(p1, &iCol1);
+      p2++;
+      p2 += sqlite3Fts3GetVarint32(p2, &iCol2);
+    }
+
+    /* Advance pointer p1 or p2 (whichever corresponds to the smaller of
+    ** iCol1 and iCol2) so that it points to either the 0x00 that marks the
+    ** end of the position list, or the 0x01 that precedes the next
+    ** column-number in the position list.
+    */
+    else if( iCol1<iCol2 ){
+      fts3ColumnlistCopy(0, &p1);
+      if( 0==*p1 ) break;
+      p1++;
+      p1 += sqlite3Fts3GetVarint32(p1, &iCol1);
+    }else{
+      fts3ColumnlistCopy(0, &p2);
+      if( 0==*p2 ) break;
+      p2++;
+      p2 += sqlite3Fts3GetVarint32(p2, &iCol2);
+    }
+  }
+
+  fts3PoslistCopy(0, &p2);
+  fts3PoslistCopy(0, &p1);
+  *pp1 = p1;
+  *pp2 = p2;
+  if( !pp || *pp==p ){
+    return 0;
+  }
+  *p++ = 0x00;
+  *pp = p;
+  return 1;
+}
+
+static int fts3PoslistNearMerge(
+  char **pp,                      /* Output buffer */
+  char *aTmp,                     /* Temporary buffer space */
+  int nRight,                     /* Maximum difference in token positions */
+  int nLeft,                      /* Maximum difference in token positions */
+  char **pp1,                     /* Left input list */
+  char **pp2                      /* Right input list */
+){
+  char *p1 = *pp1;
+  char *p2 = *pp2;
+
+  if( !pp ){
+    if( fts3PoslistPhraseMerge(0, nRight, 0, pp1, pp2) ) return 1;
+    *pp1 = p1;
+    *pp2 = p2;
+    return fts3PoslistPhraseMerge(0, nLeft, 0, pp2, pp1);
+  }else{
+    char *pTmp1 = aTmp;
+    char *pTmp2;
+    char *aTmp2;
+    int res = 1;
+
+    fts3PoslistPhraseMerge(&pTmp1, nRight, 0, pp1, pp2);
+    aTmp2 = pTmp2 = pTmp1;
+    *pp1 = p1;
+    *pp2 = p2;
+    fts3PoslistPhraseMerge(&pTmp2, nLeft, 1, pp2, pp1);
+    if( pTmp1!=aTmp && pTmp2!=aTmp2 ){
+      fts3PoslistMerge(pp, &aTmp, &aTmp2);
+    }else if( pTmp1!=aTmp ){
+      fts3PoslistCopy(pp, &aTmp);
+    }else if( pTmp2!=aTmp2 ){
+      fts3PoslistCopy(pp, &aTmp2);
+    }else{
+      res = 0;
+    }
+
+    return res;
+  }
+}
+
+/*
+** Values that may be used as the first parameter to fts3DoclistMerge().
+*/
+#define MERGE_NOT        2        /* D + D -> D */
+#define MERGE_AND        3        /* D + D -> D */
+#define MERGE_OR         4        /* D + D -> D */
+#define MERGE_POS_OR     5        /* P + P -> P */
+#define MERGE_PHRASE     6        /* P + P -> D */
+#define MERGE_POS_PHRASE 7        /* P + P -> P */
+#define MERGE_NEAR       8        /* P + P -> D */
+#define MERGE_POS_NEAR   9        /* P + P -> P */
+
+/*
+** Merge the two doclists passed in buffer a1 (size n1 bytes) and a2
+** (size n2 bytes). The output is written to pre-allocated buffer aBuffer,
+** which is guaranteed to be large enough to hold the results. The number
+** of bytes written to aBuffer is stored in *pnBuffer before returning.
+**
+** If successful, SQLITE_OK is returned. Otherwise, if a malloc error
+** occurs while allocating a temporary buffer as part of the merge operation,
+** SQLITE_NOMEM is returned.
+*/
+static int fts3DoclistMerge(
+  int mergetype,                  /* One of the MERGE_XXX constants */
+  int nParam1,                    /* Used by MERGE_NEAR and MERGE_POS_NEAR */
+  int nParam2,                    /* Used by MERGE_NEAR and MERGE_POS_NEAR */
+  char *aBuffer,                  /* Pre-allocated output buffer */
+  int *pnBuffer,                  /* OUT: Bytes written to aBuffer */
+  char *a1,                       /* Buffer containing first doclist */
+  int n1,                         /* Size of buffer a1 */
+  char *a2,                       /* Buffer containing second doclist */
+  int n2                          /* Size of buffer a2 */
+){
+  sqlite3_int64 i1 = 0;
+  sqlite3_int64 i2 = 0;
+  sqlite3_int64 iPrev = 0;
+
+  char *p = aBuffer;
+  char *p1 = a1;
+  char *p2 = a2;
+  char *pEnd1 = &a1[n1];
+  char *pEnd2 = &a2[n2];
+
+  assert( mergetype==MERGE_OR     || mergetype==MERGE_POS_OR
+       || mergetype==MERGE_AND    || mergetype==MERGE_NOT
+       || mergetype==MERGE_PHRASE || mergetype==MERGE_POS_PHRASE
+       || mergetype==MERGE_NEAR   || mergetype==MERGE_POS_NEAR
+  );
+
+  if( !aBuffer ){
+    return SQLITE_NOMEM;
+  }
+
+  /* Read the first docid from each doclist */
+  fts3GetDeltaVarint2(&p1, pEnd1, &i1);
+  fts3GetDeltaVarint2(&p2, pEnd2, &i2);
+
+  switch( mergetype ){
+    case MERGE_OR:
+    case MERGE_POS_OR:
+      while( p1 || p2 ){
+        if( p2 && p1 && i1==i2 ){
+          fts3PutDeltaVarint(&p, &iPrev, i1);
+          if( mergetype==MERGE_POS_OR ) fts3PoslistMerge(&p, &p1, &p2);
+          fts3GetDeltaVarint2(&p1, pEnd1, &i1);
+          fts3GetDeltaVarint2(&p2, pEnd2, &i2);
+        }else if( !p2 || (p1 && i1<i2) ){
+          fts3PutDeltaVarint(&p, &iPrev, i1);
+          if( mergetype==MERGE_POS_OR ) fts3PoslistCopy(&p, &p1);
+          fts3GetDeltaVarint2(&p1, pEnd1, &i1);
+        }else{
+          fts3PutDeltaVarint(&p, &iPrev, i2);
+          if( mergetype==MERGE_POS_OR ) fts3PoslistCopy(&p, &p2);
+          fts3GetDeltaVarint2(&p2, pEnd2, &i2);
+        }
+      }
+      break;
+
+    case MERGE_AND:
+      while( p1 && p2 ){
+        if( i1==i2 ){
+          fts3PutDeltaVarint(&p, &iPrev, i1);
+          fts3GetDeltaVarint2(&p1, pEnd1, &i1);
+          fts3GetDeltaVarint2(&p2, pEnd2, &i2);
+        }else if( i1<i2 ){
+          fts3GetDeltaVarint2(&p1, pEnd1, &i1);
+        }else{
+          fts3GetDeltaVarint2(&p2, pEnd2, &i2);
+        }
+      }
+      break;
+
+    case MERGE_NOT:
+      while( p1 ){
+        if( p2 && i1==i2 ){
+          fts3GetDeltaVarint2(&p1, pEnd1, &i1);
+          fts3GetDeltaVarint2(&p2, pEnd2, &i2);
+        }else if( !p2 || i1<i2 ){
+          fts3PutDeltaVarint(&p, &iPrev, i1);
+          fts3GetDeltaVarint2(&p1, pEnd1, &i1);
+        }else{
+          fts3GetDeltaVarint2(&p2, pEnd2, &i2);
+        }
+      }
+      break;
+
+    case MERGE_POS_PHRASE:
+    case MERGE_PHRASE: {
+      char **ppPos = (mergetype==MERGE_PHRASE ? 0 : &p);
+      while( p1 && p2 ){
+        if( i1==i2 ){
+          char *pSave = p;
+          sqlite3_int64 iPrevSave = iPrev;
+          fts3PutDeltaVarint(&p, &iPrev, i1);
+          if( 0==fts3PoslistPhraseMerge(ppPos, 1, 0, &p1, &p2) ){
+            p = pSave;
+            iPrev = iPrevSave;
+          }
+          fts3GetDeltaVarint2(&p1, pEnd1, &i1);
+          fts3GetDeltaVarint2(&p2, pEnd2, &i2);
+        }else if( i1<i2 ){
+          fts3PoslistCopy(0, &p1);
+          fts3GetDeltaVarint2(&p1, pEnd1, &i1);
+        }else{
+          fts3PoslistCopy(0, &p2);
+          fts3GetDeltaVarint2(&p2, pEnd2, &i2);
+        }
+      }
+      break;
+    }
+
+    case MERGE_POS_NEAR:
+    case MERGE_NEAR: {
+      char *aTmp = 0;
+      char **ppPos = 0;
+      if( mergetype==MERGE_POS_NEAR ){
+        ppPos = &p;
+        aTmp = sqlite3_malloc(2*(n1+n2));
+        if( !aTmp ){
+          return SQLITE_NOMEM;
+        }
+      }
+
+      while( p1 && p2 ){
+        if( i1==i2 ){
+          char *pSave = p;
+          sqlite3_int64 iPrevSave = iPrev;
+          fts3PutDeltaVarint(&p, &iPrev, i1);
+
+          if( !fts3PoslistNearMerge(ppPos, aTmp, nParam1, nParam2, &p1, &p2) ){
+            iPrev = iPrevSave;
+            p = pSave;
+          }
+
+          fts3GetDeltaVarint2(&p1, pEnd1, &i1);
+          fts3GetDeltaVarint2(&p2, pEnd2, &i2);
+        }else if( i1<i2 ){
+          fts3PoslistCopy(0, &p1);
+          fts3GetDeltaVarint2(&p1, pEnd1, &i1);
+        }else{
+          fts3PoslistCopy(0, &p2);
+          fts3GetDeltaVarint2(&p2, pEnd2, &i2);
+        }
+      }
+      sqlite3_free(aTmp);
+      break;
+    }
+
+    default:
+      assert(!"Invalid mergetype value passed to fts3DoclistMerge()");
+  }
+
+  *pnBuffer = (p-aBuffer);
+  return SQLITE_OK;
+}
+
+/*
+** A pointer to an instance of this structure is used as the context
+** argument to sqlite3Fts3SegReaderIterate()
+*/
+typedef struct TermSelect TermSelect;
+struct TermSelect {
+  int isReqPos;
+  char *aOutput;                  /* Malloc'd output buffer */
+  int nOutput;                    /* Size of output in bytes */
+};
+
+/*
+** This function is used as the sqlite3Fts3SegReaderIterate() callback when
+** querying the full-text index for a doclist associated with a term or
+** term-prefix.
+*/
+static int fts3TermSelectCb(
+  Fts3Table *p,                   /* Virtual table object */
+  void *pContext,                 /* Pointer to TermSelect structure */
+  char *zTerm,
+  int nTerm,
+  char *aDoclist,
+  int nDoclist
+){
+  TermSelect *pTS = (TermSelect *)pContext;
+  int nNew = pTS->nOutput + nDoclist;
+  char *aNew = sqlite3_malloc(nNew);
+
+  if( !aNew ){
+    return SQLITE_NOMEM;
+  }
+
+  if( pTS->nOutput==0 ){
+    /* If this is the first term selected, copy the doclist to the output
+    ** buffer using memcpy(). TODO: Add a way to transfer control of the
+    ** aDoclist buffer from the caller so as to avoid the memcpy().
+    */
+    memcpy(aNew, aDoclist, nDoclist);
+  }else{
+    /* The output buffer is not empty. Merge doclist aDoclist with the
+    ** existing output. This can only happen with prefix-searches (as
+    ** searches for exact terms return exactly one doclist).
+    */
+    int mergetype = (pTS->isReqPos ? MERGE_POS_OR : MERGE_OR);
+    fts3DoclistMerge(mergetype, 0, 0,
+        aNew, &nNew, pTS->aOutput, pTS->nOutput, aDoclist, nDoclist
+    );
+  }
+
+  sqlite3_free(pTS->aOutput);
+  pTS->aOutput = aNew;
+  pTS->nOutput = nNew;
+
+  return SQLITE_OK;
+}
+
+/*
+** This function retreives the doclist for the specified term (or term
+** prefix) from the database.
+**
+** The returned doclist may be in one of two formats, depending on the
+** value of parameter isReqPos. If isReqPos is zero, then the doclist is
+** a sorted list of delta-compressed docids. If isReqPos is non-zero,
+** then the returned list is in the same format as is stored in the
+** database without the found length specifier at the start of on-disk
+** doclists.
+*/
+static int fts3TermSelect(
+  Fts3Table *p,                   /* Virtual table handle */
+  int iColumn,                    /* Column to query (or -ve for all columns) */
+  const char *zTerm,              /* Term to query for */
+  int nTerm,                      /* Size of zTerm in bytes */
+  int isPrefix,                   /* True for a prefix search */
+  int isReqPos,                   /* True to include position lists in output */
+  int *pnOut,                     /* OUT: Size of buffer at *ppOut */
+  char **ppOut                    /* OUT: Malloced result buffer */
+){
+  int i;
+  TermSelect tsc;
+  Fts3SegFilter filter;           /* Segment term filter configuration */
+  Fts3SegReader **apSegment = 0;  /* Array of segments to read data from */
+  int nSegment = 0;               /* Size of apSegment array */
+  int nAlloc = 0;                 /* Allocated size of segment array */
+  int rc;                         /* Return code */
+  sqlite3_stmt *pStmt;            /* SQL statement to scan %_segdir table */
+  int iAge = 0;                   /* Used to assign ages to segments */
+
+  /* Loop through the entire %_segdir table. For each segment, create a
+  ** Fts3SegReader to iterate through the subset of the segment leaves
+  ** that may contain a term that matches zTerm/nTerm. For non-prefix
+  ** searches, this is always a single leaf. For prefix searches, this
+  ** may be a contiguous block of leaves.
+  **
+  ** The code in this loop does not actually load any leaves into memory
+  ** (unless the root node happens to be a leaf). It simply examines the
+  ** b-tree structure to determine which leaves need to be inspected.
+  */
+  rc = sqlite3Fts3AllSegdirs(p, &pStmt);
+  while( rc==SQLITE_OK && SQLITE_ROW==(rc = sqlite3_step(pStmt)) ){
+    Fts3SegReader *pNew = 0;
+    int nRoot = sqlite3_column_bytes(pStmt, 4);
+    char const *zRoot = sqlite3_column_blob(pStmt, 4);
+    if( sqlite3_column_int64(pStmt, 1)==0 ){
+      /* The entire segment is stored on the root node (which must be a
+      ** leaf). Do not bother inspecting any data in this case, just
+      ** create a Fts3SegReader to scan the single leaf.
+      */
+      rc = sqlite3Fts3SegReaderNew(p, iAge, 0, 0, 0, zRoot, nRoot, &pNew);
+    }else{
+      sqlite3_int64 i1;
+      rc = fts3SelectLeaf(p, zTerm, nTerm, zRoot, nRoot, &i1);
+      if( rc==SQLITE_OK ){
+        sqlite3_int64 i2 = sqlite3_column_int64(pStmt, 2);
+        rc = sqlite3Fts3SegReaderNew(p, iAge, i1, i2, 0, 0, 0, &pNew);
+      }
+    }
+    iAge++;
+
+    /* If a new Fts3SegReader was allocated, add it to the apSegment array. */
+    assert( (rc==SQLITE_OK)==(pNew!=0) );
+    if( pNew ){
+      if( nSegment==nAlloc ){
+        nAlloc += 16;
+        Fts3SegReader **pArray = (Fts3SegReader **)sqlite3_realloc(
+            apSegment, nAlloc*sizeof(Fts3SegReader *)
+        );
+        if( !pArray ){
+          sqlite3Fts3SegReaderFree(p, pNew);
+          rc = SQLITE_NOMEM;
+          goto finished;
+        }
+        apSegment = pArray;
+      }
+      apSegment[nSegment++] = pNew;
+    }
+  }
+  if( rc!=SQLITE_DONE ){
+    assert( rc!=SQLITE_OK );
+    goto finished;
+  }
+
+  memset(&tsc, 0, sizeof(TermSelect));
+  tsc.isReqPos = isReqPos;
+
+  filter.flags = FTS3_SEGMENT_IGNORE_EMPTY
+        | (isPrefix ? FTS3_SEGMENT_PREFIX : 0)
+        | (isReqPos ? FTS3_SEGMENT_REQUIRE_POS : 0)
+        | (iColumn<p->nColumn ? FTS3_SEGMENT_COLUMN_FILTER : 0);
+  filter.iCol = iColumn;
+  filter.zTerm = zTerm;
+  filter.nTerm = nTerm;
+
+  rc = sqlite3Fts3SegReaderIterate(p, apSegment, nSegment, &filter,
+      fts3TermSelectCb, (void *)&tsc
+  );
+
+  if( rc==SQLITE_OK ){
+    *ppOut = tsc.aOutput;
+    *pnOut = tsc.nOutput;
+  }else{
+    sqlite3_free(tsc.aOutput);
+  }
+
+finished:
+  sqlite3_reset(pStmt);
+  for(i=0; i<nSegment; i++){
+    sqlite3Fts3SegReaderFree(p, apSegment[i]);
+  }
+  sqlite3_free(apSegment);
+  return rc;
+}
+
+
+/*
+** Return a DocList corresponding to the phrase *pPhrase.
+*/
+static int fts3PhraseSelect(
+  Fts3Table *p,                   /* Virtual table handle */
+  Fts3Phrase *pPhrase,            /* Phrase to return a doclist for */
+  int isReqPos,                   /* True if output should contain positions */
+  char **paOut,                   /* OUT: Pointer to malloc'd result buffer */
+  int *pnOut                      /* OUT: Size of buffer at *paOut */
+){
+  char *pOut = 0;
+  int nOut = 0;
+  int rc = SQLITE_OK;
+  int ii;
+  int iCol = pPhrase->iColumn;
+  int isTermPos = (pPhrase->nToken>1 || isReqPos);
+
+  assert( p->nPendingData==0 );
+
+  for(ii=0; ii<pPhrase->nToken; ii++){
+    struct PhraseToken *pTok = &pPhrase->aToken[ii];
+    char *z = pTok->z;            /* Next token of the phrase */
+    int n = pTok->n;              /* Size of z in bytes */
+    int isPrefix = pTok->isPrefix;/* True if token is a prefix */
+    char *pList;                  /* Pointer to token doclist */
+    int nList;                    /* Size of buffer at pList */
+
+    rc = fts3TermSelect(p, iCol, z, n, isPrefix, isTermPos, &nList, &pList);
+    if( rc!=SQLITE_OK ) break;
+
+    if( ii==0 ){
+      pOut = pList;
+      nOut = nList;
+    }else{
+      /* Merge the new term list and the current output. If this is the
+      ** last term in the phrase, and positions are not required in the
+      ** output of this function, the positions can be dropped as part
+      ** of this merge. Either way, the result of this merge will be
+      ** smaller than nList bytes. The code in fts3DoclistMerge() is written
+      ** so that it is safe to use pList as the output as well as an input
+      ** in this case.
+      */
+      int mergetype = MERGE_POS_PHRASE;
+      if( ii==pPhrase->nToken-1 && !isReqPos ){
+        mergetype = MERGE_PHRASE;
+      }
+      fts3DoclistMerge(mergetype, 0, 0, pList, &nOut, pOut, nOut, pList, nList);
+      sqlite3_free(pOut);
+      pOut = pList;
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    *paOut = pOut;
+    *pnOut = nOut;
+  }else{
+    sqlite3_free(pOut);
+  }
+  return rc;
+}
+
+/*
+** Evaluate the full-text expression pExpr against fts3 table pTab. Store
+** the resulting doclist in *paOut and *pnOut.
+*/
+static int evalFts3Expr(
+  Fts3Table *p,                   /* Virtual table handle */
+  Fts3Expr *pExpr,                /* Parsed fts3 expression */
+  char **paOut,                   /* OUT: Pointer to malloc'd result buffer */
+  int *pnOut                      /* OUT: Size of buffer at *paOut */
+){
+  int rc = SQLITE_OK;             /* Return code */
+
+  /* Zero the output parameters. */
+  *paOut = 0;
+  *pnOut = 0;
+
+  if( pExpr ){
+    if( pExpr->eType==FTSQUERY_PHRASE ){
+      int isReqPos = (pExpr->pParent && pExpr->pParent->eType==FTSQUERY_NEAR);
+      rc = fts3PhraseSelect(p, pExpr->pPhrase, isReqPos, paOut, pnOut);
+    }else{
+      char *aLeft;
+      char *aRight;
+      int nLeft;
+      int nRight;
+
+      if( SQLITE_OK==(rc = evalFts3Expr(p, pExpr->pRight, &aRight, &nRight))
+       && SQLITE_OK==(rc = evalFts3Expr(p, pExpr->pLeft, &aLeft, &nLeft))
+      ){
+        switch( pExpr->eType ){
+          case FTSQUERY_NEAR: {
+            Fts3Expr *pLeft;
+            Fts3Expr *pRight;
+            int mergetype = MERGE_NEAR;
+            int nParam1;
+            int nParam2;
+            char *aBuffer;
+
+            if( pExpr->pParent && pExpr->pParent->eType==FTSQUERY_NEAR ){
+              mergetype = MERGE_POS_NEAR;
+            }
+            pLeft = pExpr->pLeft;
+            while( pLeft->eType==FTSQUERY_NEAR ){
+              pLeft=pLeft->pRight;
+            }
+            pRight = pExpr->pRight;
+            assert( pRight->eType==FTSQUERY_PHRASE );
+            assert( pLeft->eType==FTSQUERY_PHRASE );
+
+            nParam1 = pExpr->nNear+1;
+            nParam2 = nParam1+pLeft->pPhrase->nToken+pRight->pPhrase->nToken-2;
+            aBuffer = sqlite3_malloc(nLeft+nRight+1);
+            rc = fts3DoclistMerge(mergetype, nParam1, nParam2, aBuffer,
+                pnOut, aLeft, nLeft, aRight, nRight
+            );
+            if( rc!=SQLITE_OK ){
+              sqlite3_free(aBuffer);
+            }else{
+              *paOut = aBuffer;
+            }
+            sqlite3_free(aLeft);
+            break;
+          }
+
+          case FTSQUERY_OR: {
+            /* Allocate a buffer for the output. The maximum size is the
+            ** sum of the sizes of the two input buffers. The +1 term is
+            ** so that a buffer of zero bytes is never allocated - this can
+            ** cause fts3DoclistMerge() to incorrectly return SQLITE_NOMEM.
+            */
+            char *aBuffer = sqlite3_malloc(nRight+nLeft+1);
+            rc = fts3DoclistMerge(MERGE_OR, 0, 0, aBuffer, pnOut,
+                aLeft, nLeft, aRight, nRight
+            );
+            *paOut = aBuffer;
+            sqlite3_free(aLeft);
+            break;
+          }
+
+          case FTSQUERY_AND:
+          case FTSQUERY_NOT: {
+            assert( FTSQUERY_NOT==MERGE_NOT && FTSQUERY_AND==MERGE_AND );
+            fts3DoclistMerge(pExpr->eType, 0, 0, aLeft, pnOut,
+                aLeft, nLeft, aRight, nRight
+            );
+            *paOut = aLeft;
+            break;
+          }
+        }
+      }
+      sqlite3_free(aRight);
+    }
+  }
+
+  return rc;
+}
+
+/*
+** This is the xFilter interface for the virtual table.  See
+** the virtual table xFilter method documentation for additional
 ** information.
-*/
-/* TODO(shess) This has become just a helper for docListMerge.
-** Consider a refactor to make this cleaner.
-*/
-static void dlwAppend(DLWriter *pWriter,
-                      const char *pData, int nData,
-                      sqlite_int64 iFirstDocid, sqlite_int64 iLastDocid){
-  sqlite_int64 iDocid = 0;
-  char c[VARINT_MAX];
-  int nFirstOld, nFirstNew;     /* Old and new varint len of first docid. */
-#ifndef NDEBUG
-  sqlite_int64 iLastDocidDelta;
-#endif
-
-  /* Recode the initial docid as delta from iPrevDocid. */
-  nFirstOld = fts3GetVarint(pData, &iDocid);
-  assert( nFirstOld<nData || (nFirstOld==nData && pWriter->iType==DL_DOCIDS) );
-  nFirstNew = fts3PutVarint(c, iFirstDocid-pWriter->iPrevDocid);
-
-  /* Verify that the incoming doclist is valid AND that it ends with
-  ** the expected docid.  This is essential because we'll trust this
-  ** docid in future delta-encoding.
-  */
-  ASSERT_VALID_DOCLIST(pWriter->iType, pData, nData, &iLastDocidDelta);
-  assert( iLastDocid==iFirstDocid-iDocid+iLastDocidDelta );
-
-  /* Append recoded initial docid and everything else.  Rest of docids
-  ** should have been delta-encoded from previous initial docid.
-  */
-  if( nFirstOld<nData ){
-    dataBufferAppend2(pWriter->b, c, nFirstNew,
-                      pData+nFirstOld, nData-nFirstOld);
-  }else{
-    dataBufferAppend(pWriter->b, c, nFirstNew);
-  }
-  pWriter->iPrevDocid = iLastDocid;
-}
-static void dlwCopy(DLWriter *pWriter, DLReader *pReader){
-  dlwAppend(pWriter, dlrDocData(pReader), dlrDocDataBytes(pReader),
-            dlrDocid(pReader), dlrDocid(pReader));
-}
-static void dlwAdd(DLWriter *pWriter, sqlite_int64 iDocid){
-  char c[VARINT_MAX];
-  int n = fts3PutVarint(c, iDocid-pWriter->iPrevDocid);
-
-  /* Docids must ascend. */
-  assert( !pWriter->has_iPrevDocid || iDocid>pWriter->iPrevDocid );
-  assert( pWriter->iType==DL_DOCIDS );
-
-  dataBufferAppend(pWriter->b, c, n);
-  pWriter->iPrevDocid = iDocid;
-#ifndef NDEBUG
-  pWriter->has_iPrevDocid = 1;
-#endif
-}
-
-/*******************************************************************/
-/* PLReader is used to read data from a document's position list.  As
-** the caller steps through the list, data is cached so that varints
-** only need to be decoded once.
-**
-** plrInit, plrDestroy - create/destroy a reader.
-** plrColumn, plrPosition, plrStartOffset, plrEndOffset - accessors
-** plrAtEnd - at end of stream, only call plrDestroy once true.
-** plrStep - step to the next element.
-*/
-typedef struct PLReader {
-  /* These refer to the next position's data.  nData will reach 0 when
-  ** reading the last position, so plrStep() signals EOF by setting
-  ** pData to NULL.
-  */
-  const char *pData;
-  int nData;
-
-  DocListType iType;
-  int iColumn;         /* the last column read */
-  int iPosition;       /* the last position read */
-  int iStartOffset;    /* the last start offset read */
-  int iEndOffset;      /* the last end offset read */
-} PLReader;
-
-static int plrAtEnd(PLReader *pReader){
-  return pReader->pData==NULL;
-}
-static int plrColumn(PLReader *pReader){
-  assert( !plrAtEnd(pReader) );
-  return pReader->iColumn;
-}
-static int plrPosition(PLReader *pReader){
-  assert( !plrAtEnd(pReader) );
-  return pReader->iPosition;
-}
-static int plrStartOffset(PLReader *pReader){
-  assert( !plrAtEnd(pReader) );
-  return pReader->iStartOffset;
-}
-static int plrEndOffset(PLReader *pReader){
-  assert( !plrAtEnd(pReader) );
-  return pReader->iEndOffset;
-}
-static void plrStep(PLReader *pReader){
-  int i, n;
-
-  assert( !plrAtEnd(pReader) );
-
-  if( pReader->nData==0 ){
-    pReader->pData = NULL;
-    return;
-  }
-
-  n = fts3GetVarint32(pReader->pData, &i);
-  if( i==POS_COLUMN ){
-    n += fts3GetVarint32(pReader->pData+n, &pReader->iColumn);
-    pReader->iPosition = 0;
-    pReader->iStartOffset = 0;
-    n += fts3GetVarint32(pReader->pData+n, &i);
-  }
-  /* Should never see adjacent column changes. */
-  assert( i!=POS_COLUMN );
-
-  if( i==POS_END ){
-    pReader->nData = 0;
-    pReader->pData = NULL;
-    return;
-  }
-
-  pReader->iPosition += i-POS_BASE;
-  if( pReader->iType==DL_POSITIONS_OFFSETS ){
-    n += fts3GetVarint32(pReader->pData+n, &i);
-    pReader->iStartOffset += i;
-    n += fts3GetVarint32(pReader->pData+n, &i);
-    pReader->iEndOffset = pReader->iStartOffset+i;
-  }
-  assert( n<=pReader->nData );
-  pReader->pData += n;
-  pReader->nData -= n;
-}
-
-static void plrInit(PLReader *pReader, DLReader *pDLReader){
-  pReader->pData = dlrPosData(pDLReader);
-  pReader->nData = dlrPosDataLen(pDLReader);
-  pReader->iType = pDLReader->iType;
-  pReader->iColumn = 0;
-  pReader->iPosition = 0;
-  pReader->iStartOffset = 0;
-  pReader->iEndOffset = 0;
-  plrStep(pReader);
-}
-static void plrDestroy(PLReader *pReader){
-  SCRAMBLE(pReader);
-}
-
-/*******************************************************************/
-/* PLWriter is used in constructing a document's position list.  As a
-** convenience, if iType is DL_DOCIDS, PLWriter becomes a no-op.
-** PLWriter writes to the associated DLWriter's buffer.
-**
-** plwInit - init for writing a document's poslist.
-** plwDestroy - clear a writer.
-** plwAdd - append position and offset information.
-** plwCopy - copy next position's data from reader to writer.
-** plwTerminate - add any necessary doclist terminator.
-**
-** Calling plwAdd() after plwTerminate() may result in a corrupt
-** doclist.
-*/
-/* TODO(shess) Until we've written the second item, we can cache the
-** first item's information.  Then we'd have three states:
-**
-** - initialized with docid, no positions.
-** - docid and one position.
-** - docid and multiple positions.
-**
-** Only the last state needs to actually write to dlw->b, which would
-** be an improvement in the DLCollector case.
-*/
-typedef struct PLWriter {
-  DLWriter *dlw;
-
-  int iColumn;    /* the last column written */
-  int iPos;       /* the last position written */
-  int iOffset;    /* the last start offset written */
-} PLWriter;
-
-/* TODO(shess) In the case where the parent is reading these values
-** from a PLReader, we could optimize to a copy if that PLReader has
-** the same type as pWriter.
-*/
-static void plwAdd(PLWriter *pWriter, int iColumn, int iPos,
-                   int iStartOffset, int iEndOffset){
-  /* Worst-case space for POS_COLUMN, iColumn, iPosDelta,
-  ** iStartOffsetDelta, and iEndOffsetDelta.
-  */
-  char c[5*VARINT_MAX];
-  int n = 0;
-
-  /* Ban plwAdd() after plwTerminate(). */
-  assert( pWriter->iPos!=-1 );
-
-  if( pWriter->dlw->iType==DL_DOCIDS ) return;
-
-  if( iColumn!=pWriter->iColumn ){
-    n += fts3PutVarint(c+n, POS_COLUMN);
-    n += fts3PutVarint(c+n, iColumn);
-    pWriter->iColumn = iColumn;
-    pWriter->iPos = 0;
-    pWriter->iOffset = 0;
-  }
-  assert( iPos>=pWriter->iPos );
-  n += fts3PutVarint(c+n, POS_BASE+(iPos-pWriter->iPos));
-  pWriter->iPos = iPos;
-  if( pWriter->dlw->iType==DL_POSITIONS_OFFSETS ){
-    assert( iStartOffset>=pWriter->iOffset );
-    n += fts3PutVarint(c+n, iStartOffset-pWriter->iOffset);
-    pWriter->iOffset = iStartOffset;
-    assert( iEndOffset>=iStartOffset );
-    n += fts3PutVarint(c+n, iEndOffset-iStartOffset);
-  }
-  dataBufferAppend(pWriter->dlw->b, c, n);
-}
-static void plwCopy(PLWriter *pWriter, PLReader *pReader){
-  plwAdd(pWriter, plrColumn(pReader), plrPosition(pReader),
-         plrStartOffset(pReader), plrEndOffset(pReader));
-}
-static void plwInit(PLWriter *pWriter, DLWriter *dlw, sqlite_int64 iDocid){
-  char c[VARINT_MAX];
-  int n;
-
-  pWriter->dlw = dlw;
-
-  /* Docids must ascend. */
-  assert( !pWriter->dlw->has_iPrevDocid || iDocid>pWriter->dlw->iPrevDocid );
-  n = fts3PutVarint(c, iDocid-pWriter->dlw->iPrevDocid);
-  dataBufferAppend(pWriter->dlw->b, c, n);
-  pWriter->dlw->iPrevDocid = iDocid;
-#ifndef NDEBUG
-  pWriter->dlw->has_iPrevDocid = 1;
-#endif
-
-  pWriter->iColumn = 0;
-  pWriter->iPos = 0;
-  pWriter->iOffset = 0;
-}
-/* TODO(shess) Should plwDestroy() also terminate the doclist?  But
-** then plwDestroy() would no longer be just a destructor, it would
-** also be doing work, which isn't consistent with the overall idiom.
-** Another option would be for plwAdd() to always append any necessary
-** terminator, so that the output is always correct.  But that would
-** add incremental work to the common case with the only benefit being
-** API elegance.  Punt for now.
-*/
-static void plwTerminate(PLWriter *pWriter){
-  if( pWriter->dlw->iType>DL_DOCIDS ){
-    char c[VARINT_MAX];
-    int n = fts3PutVarint(c, POS_END);
-    dataBufferAppend(pWriter->dlw->b, c, n);
-  }
-#ifndef NDEBUG
-  /* Mark as terminated for assert in plwAdd(). */
-  pWriter->iPos = -1;
-#endif
-}
-static void plwDestroy(PLWriter *pWriter){
-  SCRAMBLE(pWriter);
-}
-
-/*******************************************************************/
-/* DLCollector wraps PLWriter and DLWriter to provide a
-** dynamically-allocated doclist area to use during tokenization.
-**
-** dlcNew - malloc up and initialize a collector.
-** dlcDelete - destroy a collector and all contained items.
-** dlcAddPos - append position and offset information.
-** dlcAddDoclist - add the collected doclist to the given buffer.
-** dlcNext - terminate the current document and open another.
-*/
-typedef struct DLCollector {
-  DataBuffer b;
-  DLWriter dlw;
-  PLWriter plw;
-} DLCollector;
-
-/* TODO(shess) This could also be done by calling plwTerminate() and
-** dataBufferAppend().  I tried that, expecting nominal performance
-** differences, but it seemed to pretty reliably be worth 1% to code
-** it this way.  I suspect it is the incremental malloc overhead (some
-** percentage of the plwTerminate() calls will cause a realloc), so
-** this might be worth revisiting if the DataBuffer implementation
-** changes.
-*/
-static void dlcAddDoclist(DLCollector *pCollector, DataBuffer *b){
-  if( pCollector->dlw.iType>DL_DOCIDS ){
-    char c[VARINT_MAX];
-    int n = fts3PutVarint(c, POS_END);
-    dataBufferAppend2(b, pCollector->b.pData, pCollector->b.nData, c, n);
-  }else{
-    dataBufferAppend(b, pCollector->b.pData, pCollector->b.nData);
-  }
-}
-static void dlcNext(DLCollector *pCollector, sqlite_int64 iDocid){
-  plwTerminate(&pCollector->plw);
-  plwDestroy(&pCollector->plw);
-  plwInit(&pCollector->plw, &pCollector->dlw, iDocid);
-}
-static void dlcAddPos(DLCollector *pCollector, int iColumn, int iPos,
-                      int iStartOffset, int iEndOffset){
-  plwAdd(&pCollector->plw, iColumn, iPos, iStartOffset, iEndOffset);
-}
-
-static DLCollector *dlcNew(sqlite_int64 iDocid, DocListType iType){
-  DLCollector *pCollector = sqlite3_malloc(sizeof(DLCollector));
-  dataBufferInit(&pCollector->b, 0);
-  dlwInit(&pCollector->dlw, iType, &pCollector->b);
-  plwInit(&pCollector->plw, &pCollector->dlw, iDocid);
-  return pCollector;
-}
-static void dlcDelete(DLCollector *pCollector){
-  plwDestroy(&pCollector->plw);
-  dlwDestroy(&pCollector->dlw);
-  dataBufferDestroy(&pCollector->b);
-  SCRAMBLE(pCollector);
-  sqlite3_free(pCollector);
-}
-
-
-/* Copy the doclist data of iType in pData/nData into *out, trimming
-** unnecessary data as we go.  Only columns matching iColumn are
-** copied, all columns copied if iColumn is -1.  Elements with no
-** matching columns are dropped.  The output is an iOutType doclist.
-*/
-/* NOTE(shess) This code is only valid after all doclists are merged.
-** If this is run before merges, then doclist items which represent
-** deletion will be trimmed, and will thus not effect a deletion
-** during the merge.
-*/
-static void docListTrim(DocListType iType, const char *pData, int nData,
-                        int iColumn, DocListType iOutType, DataBuffer *out){
-  DLReader dlReader;
-  DLWriter dlWriter;
-
-  assert( iOutType<=iType );
-
-  dlrInit(&dlReader, iType, pData, nData);
-  dlwInit(&dlWriter, iOutType, out);
-
-  while( !dlrAtEnd(&dlReader) ){
-    PLReader plReader;
-    PLWriter plWriter;
-    int match = 0;
-
-    plrInit(&plReader, &dlReader);
-
-    while( !plrAtEnd(&plReader) ){
-      if( iColumn==-1 || plrColumn(&plReader)==iColumn ){
-        if( !match ){
-          plwInit(&plWriter, &dlWriter, dlrDocid(&dlReader));
-          match = 1;
-        }
-        plwAdd(&plWriter, plrColumn(&plReader), plrPosition(&plReader),
-               plrStartOffset(&plReader), plrEndOffset(&plReader));
-      }
-      plrStep(&plReader);
-    }
-    if( match ){
-      plwTerminate(&plWriter);
-      plwDestroy(&plWriter);
-    }
-
-    plrDestroy(&plReader);
-    dlrStep(&dlReader);
-  }
-  dlwDestroy(&dlWriter);
-  dlrDestroy(&dlReader);
-}
-
-/* Used by docListMerge() to keep doclists in the ascending order by
-** docid, then ascending order by age (so the newest comes first).
-*/
-typedef struct OrderedDLReader {
-  DLReader *pReader;
-
-  /* TODO(shess) If we assume that docListMerge pReaders is ordered by
-  ** age (which we do), then we could use pReader comparisons to break
-  ** ties.
-  */
-  int idx;
-} OrderedDLReader;
-
-/* Order eof to end, then by docid asc, idx desc. */
-static int orderedDLReaderCmp(OrderedDLReader *r1, OrderedDLReader *r2){
-  if( dlrAtEnd(r1->pReader) ){
-    if( dlrAtEnd(r2->pReader) ) return 0;  /* Both atEnd(). */
-    return 1;                              /* Only r1 atEnd(). */
-  }
-  if( dlrAtEnd(r2->pReader) ) return -1;   /* Only r2 atEnd(). */
-
-  if( dlrDocid(r1->pReader)<dlrDocid(r2->pReader) ) return -1;
-  if( dlrDocid(r1->pReader)>dlrDocid(r2->pReader) ) return 1;
-
-  /* Descending on idx. */
-  return r2->idx-r1->idx;
-}
-
-/* Bubble p[0] to appropriate place in p[1..n-1].  Assumes that
-** p[1..n-1] is already sorted.
-*/
-/* TODO(shess) Is this frequent enough to warrant a binary search?
-** Before implementing that, instrument the code to check.  In most
-** current usage, I expect that p[0] will be less than p[1] a very
-** high proportion of the time.
-*/
-static void orderedDLReaderReorder(OrderedDLReader *p, int n){
-  while( n>1 && orderedDLReaderCmp(p, p+1)>0 ){
-    OrderedDLReader tmp = p[0];
-    p[0] = p[1];
-    p[1] = tmp;
-    n--;
-    p++;
-  }
-}
-
-/* Given an array of doclist readers, merge their doclist elements
-** into out in sorted order (by docid), dropping elements from older
-** readers when there is a duplicate docid.  pReaders is assumed to be
-** ordered by age, oldest first.
-*/
-/* TODO(shess) nReaders must be <= MERGE_COUNT.  This should probably
-** be fixed.
-*/
-static void docListMerge(DataBuffer *out,
-                         DLReader *pReaders, int nReaders){
-  OrderedDLReader readers[MERGE_COUNT];
-  DLWriter writer;
-  int i, n;
-  const char *pStart = 0;
-  int nStart = 0;
-  sqlite_int64 iFirstDocid = 0, iLastDocid = 0;
-
-  assert( nReaders>0 );
-  if( nReaders==1 ){
-    dataBufferAppend(out, dlrDocData(pReaders), dlrAllDataBytes(pReaders));
-    return;
-  }
-
-  assert( nReaders<=MERGE_COUNT );
-  n = 0;
-  for(i=0; i<nReaders; i++){
-    assert( pReaders[i].iType==pReaders[0].iType );
-    readers[i].pReader = pReaders+i;
-    readers[i].idx = i;
-    n += dlrAllDataBytes(&pReaders[i]);
-  }
-  /* Conservatively size output to sum of inputs.  Output should end
-  ** up strictly smaller than input.
-  */
-  dataBufferExpand(out, n);
-
-  /* Get the readers into sorted order. */
-  while( i-->0 ){
-    orderedDLReaderReorder(readers+i, nReaders-i);
-  }
-
-  dlwInit(&writer, pReaders[0].iType, out);
-  while( !dlrAtEnd(readers[0].pReader) ){
-    sqlite_int64 iDocid = dlrDocid(readers[0].pReader);
-
-    /* If this is a continuation of the current buffer to copy, extend
-    ** that buffer.  memcpy() seems to be more efficient if it has a
-    ** lots of data to copy.
-    */
-    if( dlrDocData(readers[0].pReader)==pStart+nStart ){
-      nStart += dlrDocDataBytes(readers[0].pReader);
-    }else{
-      if( pStart!=0 ){
-        dlwAppend(&writer, pStart, nStart, iFirstDocid, iLastDocid);
-      }
-      pStart = dlrDocData(readers[0].pReader);
-      nStart = dlrDocDataBytes(readers[0].pReader);
-      iFirstDocid = iDocid;
-    }
-    iLastDocid = iDocid;
-    dlrStep(readers[0].pReader);
-
-    /* Drop all of the older elements with the same docid. */
-    for(i=1; i<nReaders &&
-             !dlrAtEnd(readers[i].pReader) &&
-             dlrDocid(readers[i].pReader)==iDocid; i++){
-      dlrStep(readers[i].pReader);
-    }
-
-    /* Get the readers back into order. */
-    while( i-->0 ){
-      orderedDLReaderReorder(readers+i, nReaders-i);
-    }
-  }
-
-  /* Copy over any remaining elements. */
-  if( nStart>0 ) dlwAppend(&writer, pStart, nStart, iFirstDocid, iLastDocid);
-  dlwDestroy(&writer);
-}
-
-/* Helper function for posListUnion().  Compares the current position
-** between left and right, returning as standard C idiom of <0 if
-** left<right, >0 if left>right, and 0 if left==right.  "End" always
-** compares greater.
-*/
-static int posListCmp(PLReader *pLeft, PLReader *pRight){
-  assert( pLeft->iType==pRight->iType );
-  if( pLeft->iType==DL_DOCIDS ) return 0;
-
-  if( plrAtEnd(pLeft) ) return plrAtEnd(pRight) ? 0 : 1;
-  if( plrAtEnd(pRight) ) return -1;
-
-  if( plrColumn(pLeft)<plrColumn(pRight) ) return -1;
-  if( plrColumn(pLeft)>plrColumn(pRight) ) return 1;
-
-  if( plrPosition(pLeft)<plrPosition(pRight) ) return -1;
-  if( plrPosition(pLeft)>plrPosition(pRight) ) return 1;
-  if( pLeft->iType==DL_POSITIONS ) return 0;
-
-  if( plrStartOffset(pLeft)<plrStartOffset(pRight) ) return -1;
-  if( plrStartOffset(pLeft)>plrStartOffset(pRight) ) return 1;
-
-  if( plrEndOffset(pLeft)<plrEndOffset(pRight) ) return -1;
-  if( plrEndOffset(pLeft)>plrEndOffset(pRight) ) return 1;
-
+**
+** If idxNum==FTS3_FULLSCAN_SEARCH then do a full table scan against
+** the %_content table.
+**
+** If idxNum==FTS3_DOCID_SEARCH then do a docid lookup for a single entry
+** in the %_content table.
+**
+** If idxNum>=FTS3_FULLTEXT_SEARCH then use the full text index.  The
+** column on the left-hand side of the MATCH operator is column
+** number idxNum-FTS3_FULLTEXT_SEARCH, 0 indexed.  argv[0] is the right-hand
+** side of the MATCH operator.
+*/
+/* TODO(shess) Upgrade the cursor initialization and destruction to
+** account for fts3FilterMethod() being called multiple times on the
+** same cursor. The current solution is very fragile. Apply fix to
+** fts3 as appropriate.
+*/
+static int fts3FilterMethod(
+  sqlite3_vtab_cursor *pCursor,   /* The cursor used for this query */
+  int idxNum,                     /* Strategy index */
+  const char *idxStr,             /* Unused */
+  int nVal,                       /* Number of elements in apVal */
+  sqlite3_value **apVal           /* Arguments for the indexing scheme */
+){
+  const char *azSql[] = {
+    "SELECT * FROM %Q.'%q_content' WHERE docid = ?", /* non-full-table-scan */
+    "SELECT * FROM %Q.'%q_content'",                 /* full-table-scan */
+  };
+  int rc;                         /* Return code */
+  char *zSql;                     /* SQL statement used to access %_content */
+  Fts3Table *p = (Fts3Table *)pCursor->pVtab;
+  Fts3Cursor *pCsr = (Fts3Cursor *)pCursor;
+
+  assert( idxNum>=0 && idxNum<=(FTS3_FULLTEXT_SEARCH+p->nColumn) );
+  assert( nVal==0 || nVal==1 );
+  assert( (nVal==0)==(idxNum==FTS3_FULLSCAN_SEARCH) );
+
+  /* In case the cursor has been used before, clear it now. */
+  sqlite3_finalize(pCsr->pStmt);
+  sqlite3_free(pCsr->aDoclist);
+  memset(&pCursor[1], 0, sizeof(Fts3Cursor)-sizeof(sqlite3_vtab_cursor));
+
+  /* Compile a SELECT statement for this cursor. For a full-table-scan, the
+  ** statement loops through all rows of the %_content table. For a
+  ** full-text query or docid lookup, the statement retrieves a single
+  ** row by docid.
+  */
+  zSql = sqlite3_mprintf(azSql[idxNum==FTS3_FULLSCAN_SEARCH], p->zDb, p->zName);
+  if( !zSql ){
+    rc = SQLITE_NOMEM;
+  }else{
+    rc = sqlite3_prepare_v2(p->db, zSql, -1, &pCsr->pStmt, 0);
+    sqlite3_free(zSql);
+  }
+  if( rc!=SQLITE_OK ) return rc;
+  pCsr->eType = idxNum;
+
+  if( idxNum==FTS3_DOCID_SEARCH ){
+    rc = sqlite3_bind_value(pCsr->pStmt, 1, apVal[0]);
+  }else if( idxNum!=FTS3_FULLSCAN_SEARCH ){
+    int iCol = idxNum-FTS3_FULLTEXT_SEARCH;
+    const char *zQuery = (const char *)sqlite3_value_text(apVal[0]);
+
+    rc = sqlite3Fts3PendingTermsFlush(p);
+    if( rc!=SQLITE_OK ) return rc;
+
+    rc = sqlite3Fts3ExprParse(p->pTokenizer, p->azColumn, p->nColumn,
+        iCol, zQuery, -1, &pCsr->pExpr
+    );
+    if( rc!=SQLITE_OK ) return rc;
+
+    rc = evalFts3Expr(p, pCsr->pExpr, &pCsr->aDoclist, &pCsr->nDoclist);
+    pCsr->pNextId = pCsr->aDoclist;
+    pCsr->iPrevId = 0;
+  }
+
+  if( rc!=SQLITE_OK ) return rc;
+  return fts3NextMethod(pCursor);
+}
+
+/*
+** This is the xEof method of the virtual table. SQLite calls this
+** routine to find out if it has reached the end of a result set.
+*/
+static int fts3EofMethod(sqlite3_vtab_cursor *pCursor){
+  return ((Fts3Cursor *)pCursor)->isEof;
+}
+
+/*
+** This is the xColumn method of the virtual table.  The SQLite
+** core calls this method during a query when it needs the value
+** of a column from the virtual table.  This method needs to use
+** one of the sqlite3_result_*() routines to store the requested
+** value back in the pContext.
+*/
+static int fts3ColumnMethod(sqlite3_vtab_cursor *pCursor,
+                          sqlite3_context *pContext, int idxCol){
+  Fts3Cursor *c = (Fts3Cursor *) pCursor;
+  Fts3Table *v = cursor_vtab(c);
+  int rc = fts3CursorSeek(c);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  if( idxCol<v->nColumn ){
+    sqlite3_value *pVal = sqlite3_column_value(c->pStmt, idxCol+1);
+    sqlite3_result_value(pContext, pVal);
+  }else if( idxCol==v->nColumn ){
+    /* The extra column whose name is the same as the table.
+    ** Return a blob which is a pointer to the cursor
+    */
+    sqlite3_result_blob(pContext, &c, sizeof(c), SQLITE_TRANSIENT);
+  }else if( idxCol==v->nColumn+1 ){
+    /* The docid column, which is an alias for rowid. */
+    sqlite3_value *pVal = sqlite3_column_value(c->pStmt, 0);
+    sqlite3_result_value(pContext, pVal);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** This is the xRowid method. The SQLite core calls this routine to
+** retrieve the rowid for the current row of the result set. fts3
+** exposes %_content.docid as the rowid for the virtual table. The
+** rowid should be written to *pRowid.
+*/
+static int fts3RowidMethod(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
+  Fts3Cursor *pCsr = (Fts3Cursor *) pCursor;
+  if( pCsr->aDoclist ){
+    *pRowid = pCsr->iPrevId;
+  }else{
+    *pRowid = sqlite3_column_int64(pCsr->pStmt, 0);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** This function is the implementation of the xUpdate callback used by
+** FTS3 virtual tables. It is invoked by SQLite each time a row is to be
+** inserted, updated or deleted.
+*/
+static int fts3UpdateMethod(
+  sqlite3_vtab *pVtab,            /* Virtual table handle */
+  int nArg,                       /* Size of argument array */
+  sqlite3_value **apVal,          /* Array of arguments */
+  sqlite_int64 *pRowid            /* OUT: The affected (or effected) rowid */
+){
+  return sqlite3Fts3UpdateMethod(pVtab, nArg, apVal, pRowid);
+}
+
+/*
+** Implementation of xSync() method. Flush the contents of the pending-terms
+** hash-table to the database.
+*/
+static int fts3SyncMethod(sqlite3_vtab *pVtab){
+  return sqlite3Fts3PendingTermsFlush((Fts3Table *)pVtab);
+}
+
+/*
+** Implementation of xBegin() method. This is a no-op.
+*/
+static int fts3BeginMethod(sqlite3_vtab *pVtab){
+  assert( ((Fts3Table *)pVtab)->nPendingData==0 );
+  return SQLITE_OK;
+}
+
+/*
+** Implementation of xCommit() method. This is a no-op. The contents of
+** the pending-terms hash-table have already been flushed into the database
+** by fts3SyncMethod().
+*/
+static int fts3CommitMethod(sqlite3_vtab *pVtab){
+  assert( ((Fts3Table *)pVtab)->nPendingData==0 );
+  return SQLITE_OK;
+}
+
+/*
+** Implementation of xRollback(). Discard the contents of the pending-terms
+** hash-table. Any changes made to the database are reverted by SQLite.
+*/
+static int fts3RollbackMethod(sqlite3_vtab *pVtab){
+  sqlite3Fts3PendingTermsClear((Fts3Table *)pVtab);
+  return SQLITE_OK;
+}
+
+/*
+** Helper function used by the implementation of the overloaded snippet(),
+** offsets() and optimize() SQL functions.
+**
+** If the value passed as the third argument is a blob of size
+** sizeof(Fts3Cursor*), then the blob contents are copied to the
+** output variable *ppCsr and SQLITE_OK is returned. Otherwise, an error
+** message is written to context pContext and SQLITE_ERROR returned. The
+** string passed via zFunc is used as part of the error message.
+*/
+static int fts3FunctionArg(
+  sqlite3_context *pContext,      /* SQL function call context */
+  const char *zFunc,              /* Function name */
+  sqlite3_value *pVal,            /* argv[0] passed to function */
+  Fts3Cursor **ppCsr         /* OUT: Store cursor handle here */
+){
+  Fts3Cursor *pRet;
+  if( sqlite3_value_type(pVal)!=SQLITE_BLOB
+   && sqlite3_value_bytes(pVal)!=sizeof(Fts3Cursor *)
+  ){
+    char *zErr = sqlite3_mprintf("illegal first argument to %s", zFunc);
+    sqlite3_result_error(pContext, zErr, -1);
+    sqlite3_free(zErr);
+    return SQLITE_ERROR;
+  }
+  memcpy(&pRet, sqlite3_value_blob(pVal), sizeof(Fts3Cursor *));
+  *ppCsr = pRet;
+  return SQLITE_OK;
+}
+
+/*
+** Implementation of the snippet() function for FTS3
+*/
+static void fts3SnippetFunc(
+  sqlite3_context *pContext,
+  int argc,
+  sqlite3_value **argv
+){
+  Fts3Cursor *pCsr;               /* Cursor handle passed through apVal[0] */
+  const char *zStart = "<b>";
+  const char *zEnd = "</b>";
+  const char *zEllipsis = "<b>...</b>";
+
+  if( argc<1 || argc>4 ) return;
+  if( fts3FunctionArg(pContext, "snippet", argv[0], &pCsr) ) return;
+
+  switch( argc ){
+    case 4: zEllipsis = (const char*)sqlite3_value_text(argv[3]);
+    case 3: zEnd = (const char*)sqlite3_value_text(argv[2]);
+    case 2: zStart = (const char*)sqlite3_value_text(argv[1]);
+  }
+
+  sqlite3Fts3Snippet(pContext, pCsr, zStart, zEnd, zEllipsis);
+}
+
+/*
+** Implementation of the offsets() function for FTS3
+*/
+static void fts3OffsetsFunc(
+  sqlite3_context *pContext,      /* SQLite function call context */
+  int nVal,                       /* Size of argument array */
+  sqlite3_value **apVal           /* Array of arguments */
+){
+  Fts3Cursor *pCsr;               /* Cursor handle passed through apVal[0] */
+
+  assert( nVal==1 );
+  if( fts3FunctionArg(pContext, "offsets", apVal[0], &pCsr) ) return;
+  assert( pCsr );
+  sqlite3Fts3Offsets(pContext, pCsr);
+}
+
+/*
+** Implementation of the special optimize() function for FTS3. This
+** function merges all segments in the database to a single segment.
+** Example usage is:
+**
+**   SELECT optimize(t) FROM t LIMIT 1;
+**
+** where 't' is the name of an FTS3 table.
+*/
+static void fts3OptimizeFunc(
+  sqlite3_context *pContext,      /* SQLite function call context */
+  int nVal,                       /* Size of argument array */
+  sqlite3_value **apVal           /* Array of arguments */
+){
+  int rc;                         /* Return code */
+  Fts3Table *p;                   /* Virtual table handle */
+  Fts3Cursor *pCursor;            /* Cursor handle passed through apVal[0] */
+
+  assert( nVal==1 );
+  if( fts3FunctionArg(pContext, "optimize", apVal[0], &pCursor) ) return;
+  p = (Fts3Table *)pCursor->base.pVtab;
+  assert( p );
+
+  rc = sqlite3Fts3Optimize(p);
+
+  switch( rc ){
+    case SQLITE_OK:
+      sqlite3_result_text(pContext, "Index optimized", -1, SQLITE_STATIC);
+      break;
+    case SQLITE_DONE:
+      sqlite3_result_text(pContext, "Index already optimal", -1, SQLITE_STATIC);
+      break;
+    default:
+      sqlite3_result_error_code(pContext, rc);
+      break;
+  }
+}
+
+/*
+** This routine implements the xFindFunction method for the FTS3
+** virtual table.
+*/
+static int fts3FindFunctionMethod(
+  sqlite3_vtab *pVtab,            /* Virtual table handle */
+  int nArg,                       /* Number of SQL function arguments */
+  const char *zName,              /* Name of SQL function */
+  void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), /* OUT: Result */
+  void **ppArg                    /* Unused */
+){
+  struct Overloaded {
+    const char *zName;
+    void (*xFunc)(sqlite3_context*,int,sqlite3_value**);
+  } aOverload[] = {
+    { "snippet", fts3SnippetFunc },
+    { "offsets", fts3OffsetsFunc },
+    { "optimize", fts3OptimizeFunc },
+  };
+  int i;                          /* Iterator variable */
+  for(i=0; i<SizeofArray(aOverload); i++){
+    if( strcmp(zName, aOverload[i].zName)==0 ){
+      *pxFunc = aOverload[i].xFunc;
+      return 1;
+    }
+  }
+
+  /* No function of the specified name was found. Return 0. */
   return 0;
 }
 
-/* Write the union of position lists in pLeft and pRight to pOut.
-** "Union" in this case meaning "All unique position tuples".  Should
-** work with any doclist type, though both inputs and the output
-** should be the same type.
-*/
-static void posListUnion(DLReader *pLeft, DLReader *pRight, DLWriter *pOut){
-  PLReader left, right;
-  PLWriter writer;
-
-  assert( dlrDocid(pLeft)==dlrDocid(pRight) );
-  assert( pLeft->iType==pRight->iType );
-  assert( pLeft->iType==pOut->iType );
-
-  plrInit(&left, pLeft);
-  plrInit(&right, pRight);
-  plwInit(&writer, pOut, dlrDocid(pLeft));
-
-  while( !plrAtEnd(&left) || !plrAtEnd(&right) ){
-    int c = posListCmp(&left, &right);
-    if( c<0 ){
-      plwCopy(&writer, &left);
-      plrStep(&left);
-    }else if( c>0 ){
-      plwCopy(&writer, &right);
-      plrStep(&right);
-    }else{
-      plwCopy(&writer, &left);
-      plrStep(&left);
-      plrStep(&right);
-    }
-  }
-
-  plwTerminate(&writer);
-  plwDestroy(&writer);
-  plrDestroy(&left);
-  plrDestroy(&right);
-}
-
-/* Write the union of doclists in pLeft and pRight to pOut.  For
-** docids in common between the inputs, the union of the position
-** lists is written.  Inputs and outputs are always type DL_DEFAULT.
-*/
-static void docListUnion(
-  const char *pLeft, int nLeft,
-  const char *pRight, int nRight,
-  DataBuffer *pOut      /* Write the combined doclist here */
-){
-  DLReader left, right;
-  DLWriter writer;
-
-  if( nLeft==0 ){
-    if( nRight!=0) dataBufferAppend(pOut, pRight, nRight);
-    return;
-  }
-  if( nRight==0 ){
-    dataBufferAppend(pOut, pLeft, nLeft);
-    return;
-  }
-
-  dlrInit(&left, DL_DEFAULT, pLeft, nLeft);
-  dlrInit(&right, DL_DEFAULT, pRight, nRight);
-  dlwInit(&writer, DL_DEFAULT, pOut);
-
-  while( !dlrAtEnd(&left) || !dlrAtEnd(&right) ){
-    if( dlrAtEnd(&right) ){
-      dlwCopy(&writer, &left);
-      dlrStep(&left);
-    }else if( dlrAtEnd(&left) ){
-      dlwCopy(&writer, &right);
-      dlrStep(&right);
-    }else if( dlrDocid(&left)<dlrDocid(&right) ){
-      dlwCopy(&writer, &left);
-      dlrStep(&left);
-    }else if( dlrDocid(&left)>dlrDocid(&right) ){
-      dlwCopy(&writer, &right);
-      dlrStep(&right);
-    }else{
-      posListUnion(&left, &right, &writer);
-      dlrStep(&left);
-      dlrStep(&right);
-    }
-  }
-
-  dlrDestroy(&left);
-  dlrDestroy(&right);
-  dlwDestroy(&writer);
-}
-
-/*
-** This function is used as part of the implementation of phrase and
-** NEAR matching.
-**
-** pLeft and pRight are DLReaders positioned to the same docid in
-** lists of type DL_POSITION. This function writes an entry to the
-** DLWriter pOut for each position in pRight that is less than
-** (nNear+1) greater (but not equal to or smaller) than a position
-** in pLeft. For example, if nNear is 0, and the positions contained
-** by pLeft and pRight are:
-**
-**    pLeft:  5 10 15 20
-**    pRight: 6  9 17 21
-**
-** then the docid is added to pOut. If pOut is of type DL_POSITIONS,
-** then a positionids "6" and "21" are also added to pOut.
-**
-** If boolean argument isSaveLeft is true, then positionids are copied
-** from pLeft instead of pRight. In the example above, the positions "5"
-** and "20" would be added instead of "6" and "21".
-*/
-static void posListPhraseMerge(
-  DLReader *pLeft,
-  DLReader *pRight,
-  int nNear,
-  int isSaveLeft,
-  DLWriter *pOut
-){
-  PLReader left, right;
-  PLWriter writer;
-  int match = 0;
-
-  assert( dlrDocid(pLeft)==dlrDocid(pRight) );
-  assert( pOut->iType!=DL_POSITIONS_OFFSETS );
-
-  plrInit(&left, pLeft);
-  plrInit(&right, pRight);
-
-  while( !plrAtEnd(&left) && !plrAtEnd(&right) ){
-    if( plrColumn(&left)<plrColumn(&right) ){
-      plrStep(&left);
-    }else if( plrColumn(&left)>plrColumn(&right) ){
-      plrStep(&right);
-    }else if( plrPosition(&left)>=plrPosition(&right) ){
-      plrStep(&right);
-    }else{
-      if( (plrPosition(&right)-plrPosition(&left))<=(nNear+1) ){
-        if( !match ){
-          plwInit(&writer, pOut, dlrDocid(pLeft));
-          match = 1;
-        }
-        if( !isSaveLeft ){
-          plwAdd(&writer, plrColumn(&right), plrPosition(&right), 0, 0);
-        }else{
-          plwAdd(&writer, plrColumn(&left), plrPosition(&left), 0, 0);
-        }
-        plrStep(&right);
-      }else{
-        plrStep(&left);
-      }
-    }
-  }
-
-  if( match ){
-    plwTerminate(&writer);
-    plwDestroy(&writer);
-  }
-
-  plrDestroy(&left);
-  plrDestroy(&right);
-}
-
-/*
-** Compare the values pointed to by the PLReaders passed as arguments.
-** Return -1 if the value pointed to by pLeft is considered less than
-** the value pointed to by pRight, +1 if it is considered greater
-** than it, or 0 if it is equal. i.e.
-**
-**     (*pLeft - *pRight)
-**
-** A PLReader that is in the EOF condition is considered greater than
-** any other. If neither argument is in EOF state, the return value of
-** plrColumn() is used. If the plrColumn() values are equal, the
-** comparison is on the basis of plrPosition().
-*/
-static int plrCompare(PLReader *pLeft, PLReader *pRight){
-  assert(!plrAtEnd(pLeft) || !plrAtEnd(pRight));
-
-  if( plrAtEnd(pRight) || plrAtEnd(pLeft) ){
-    return (plrAtEnd(pRight) ? -1 : 1);
-  }
-  if( plrColumn(pLeft)!=plrColumn(pRight) ){
-    return ((plrColumn(pLeft)<plrColumn(pRight)) ? -1 : 1);
-  }
-  if( plrPosition(pLeft)!=plrPosition(pRight) ){
-    return ((plrPosition(pLeft)<plrPosition(pRight)) ? -1 : 1);
-  }
-  return 0;
-}
-
-/* We have two doclists with positions:  pLeft and pRight. Depending
-** on the value of the nNear parameter, perform either a phrase
-** intersection (if nNear==0) or a NEAR intersection (if nNear>0)
-** and write the results into pOut.
-**
-** A phrase intersection means that two documents only match
-** if pLeft.iPos+1==pRight.iPos.
-**
-** A NEAR intersection means that two documents only match if
-** (abs(pLeft.iPos-pRight.iPos)<nNear).
-**
-** If a NEAR intersection is requested, then the nPhrase argument should
-** be passed the number of tokens in the two operands to the NEAR operator
-** combined. For example:
-**
-**       Query syntax               nPhrase
-**      ------------------------------------
-**       "A B C" NEAR "D E"         5
-**       A NEAR B                   2
-**
-** iType controls the type of data written to pOut.  If iType is
-** DL_POSITIONS, the positions are those from pRight.
-*/
-static void docListPhraseMerge(
-  const char *pLeft, int nLeft,
-  const char *pRight, int nRight,
-  int nNear,            /* 0 for a phrase merge, non-zero for a NEAR merge */
-  int nPhrase,          /* Number of tokens in left+right operands to NEAR */
-  DocListType iType,    /* Type of doclist to write to pOut */
-  DataBuffer *pOut      /* Write the combined doclist here */
-){
-  DLReader left, right;
-  DLWriter writer;
-
-  if( nLeft==0 || nRight==0 ) return;
-
-  assert( iType!=DL_POSITIONS_OFFSETS );
-
-  dlrInit(&left, DL_POSITIONS, pLeft, nLeft);
-  dlrInit(&right, DL_POSITIONS, pRight, nRight);
-  dlwInit(&writer, iType, pOut);
-
-  while( !dlrAtEnd(&left) && !dlrAtEnd(&right) ){
-    if( dlrDocid(&left)<dlrDocid(&right) ){
-      dlrStep(&left);
-    }else if( dlrDocid(&right)<dlrDocid(&left) ){
-      dlrStep(&right);
-    }else{
-      if( nNear==0 ){
-        posListPhraseMerge(&left, &right, 0, 0, &writer);
+/*
+** Implementation of FTS3 xRename method. Rename an fts3 table.
+*/
+static int fts3RenameMethod(
+  sqlite3_vtab *pVtab,            /* Virtual table handle */
+  const char *zName               /* New name of table */
+){
+  Fts3Table *p = (Fts3Table *)pVtab;
+  int rc = SQLITE_NOMEM;          /* Return Code */
+  char *zSql;                     /* SQL script to run to rename tables */
+
+  zSql = sqlite3_mprintf(
+    "ALTER TABLE %Q.'%q_content'  RENAME TO '%q_content';"
+    "ALTER TABLE %Q.'%q_segments' RENAME TO '%q_segments';"
+    "ALTER TABLE %Q.'%q_segdir'   RENAME TO '%q_segdir';"
+    , p->zDb, p->zName, zName
+    , p->zDb, p->zName, zName
+    , p->zDb, p->zName, zName
+  );
+  if( zSql ){
+    rc = sqlite3_exec(p->db, zSql, 0, 0, 0);
+    sqlite3_free(zSql);
+  }
+  return rc;
+}
+
+static const sqlite3_module fts3Module = {
+  /* iVersion      */ 0,
+  /* xCreate       */ fts3CreateMethod,
+  /* xConnect      */ fts3ConnectMethod,
+  /* xBestIndex    */ fts3BestIndexMethod,
+  /* xDisconnect   */ fts3DisconnectMethod,
+  /* xDestroy      */ fts3DestroyMethod,
+  /* xOpen         */ fts3OpenMethod,
+  /* xClose        */ fulltextClose,
+  /* xFilter       */ fts3FilterMethod,
+  /* xNext         */ fts3NextMethod,
+  /* xEof          */ fts3EofMethod,
+  /* xColumn       */ fts3ColumnMethod,
+  /* xRowid        */ fts3RowidMethod,
+  /* xUpdate       */ fts3UpdateMethod,
+  /* xBegin        */ fts3BeginMethod,
+  /* xSync         */ fts3SyncMethod,
+  /* xCommit       */ fts3CommitMethod,
+  /* xRollback     */ fts3RollbackMethod,
+  /* xFindFunction */ fts3FindFunctionMethod,
+  /* xRename */       fts3RenameMethod,
+};
+
+/*
+** This function is registered as the module destructor (called when an
+** FTS3 enabled database connection is closed). It frees the memory
+** allocated for the tokenizer hash table.
+*/
+static void hashDestroy(void *p){
+  Fts3Hash *pHash = (Fts3Hash *)p;
+  sqlite3Fts3HashClear(pHash);
+  sqlite3_free(pHash);
+}
+
+/*
+** The fts3 built-in tokenizers - "simple" and "porter" - are implemented
+** in files fts3_tokenizer1.c and fts3_porter.c respectively. The following
+** two forward declarations are for functions declared in these files
+** used to retrieve the respective implementations.
+**
+** Calling sqlite3Fts3SimpleTokenizerModule() sets the value pointed
+** to by the argument to point a the "simple" tokenizer implementation.
+** Function ...PorterTokenizerModule() sets *pModule to point to the
+** porter tokenizer/stemmer implementation.
+*/
+SQLITE_PRIVATE void sqlite3Fts3SimpleTokenizerModule(sqlite3_tokenizer_module const**ppModule);
+SQLITE_PRIVATE void sqlite3Fts3PorterTokenizerModule(sqlite3_tokenizer_module const**ppModule);
+SQLITE_PRIVATE void sqlite3Fts3IcuTokenizerModule(sqlite3_tokenizer_module const**ppModule);
+
+/*
+** Initialise the fts3 extension. If this extension is built as part
+** of the sqlite library, then this function is called directly by
+** SQLite. If fts3 is built as a dynamically loadable extension, this
+** function is called by the sqlite3_extension_init() entry point.
+*/
+SQLITE_PRIVATE int sqlite3Fts3Init(sqlite3 *db){
+  int rc = SQLITE_OK;
+  Fts3Hash *pHash = 0;
+  const sqlite3_tokenizer_module *pSimple = 0;
+  const sqlite3_tokenizer_module *pPorter = 0;
+  const sqlite3_tokenizer_module *pIcu = 0;
+
+  sqlite3Fts3SimpleTokenizerModule(&pSimple);
+  sqlite3Fts3PorterTokenizerModule(&pPorter);
+#ifdef SQLITE_ENABLE_ICU
+  sqlite3Fts3IcuTokenizerModule(&pIcu);
+#endif
+
+  /* Allocate and initialise the hash-table used to store tokenizers. */
+  pHash = sqlite3_malloc(sizeof(Fts3Hash));
+  if( !pHash ){
+    rc = SQLITE_NOMEM;
+  }else{
+    sqlite3Fts3HashInit(pHash, FTS3_HASH_STRING, 1);
+  }
+
+  /* Load the built-in tokenizers into the hash table */
+  if( rc==SQLITE_OK ){
+    if( sqlite3Fts3HashInsert(pHash, "simple", 7, (void *)pSimple)
+     || sqlite3Fts3HashInsert(pHash, "porter", 7, (void *)pPorter)
+     || (pIcu && sqlite3Fts3HashInsert(pHash, "icu", 4, (void *)pIcu))
+    ){
+      rc = SQLITE_NOMEM;
+    }
+  }
+
+#ifdef SQLITE_TEST
+  sqlite3Fts3ExprInitTestInterface(db);
+#endif
+
+  /* Create the virtual table wrapper around the hash-table and overload
+  ** the two scalar functions. If this is successful, register the
+  ** module with sqlite.
+  */
+  if( SQLITE_OK==rc
+   && SQLITE_OK==(rc = sqlite3Fts3InitHashTable(db, pHash, "fts3_tokenizer"))
+   && SQLITE_OK==(rc = sqlite3_overload_function(db, "snippet", -1))
+   && SQLITE_OK==(rc = sqlite3_overload_function(db, "offsets", 1))
+   && SQLITE_OK==(rc = sqlite3_overload_function(db, "optimize", 1))
+  ){
+    return sqlite3_create_module_v2(
+        db, "fts3", &fts3Module, (void *)pHash, hashDestroy
+    );
+  }
+
+  /* An error has occurred. Delete the hash table and return the error code. */
+  assert( rc!=SQLITE_OK );
+  if( pHash ){
+    sqlite3Fts3HashClear(pHash);
+    sqlite3_free(pHash);
+  }
+  return rc;
+}
+
+#if !SQLITE_CORE
+SQLITE_API int sqlite3_extension_init(
+  sqlite3 *db,
+  char **pzErrMsg,
+  const sqlite3_api_routines *pApi
+){
+  SQLITE_EXTENSION_INIT2(pApi)
+  return sqlite3Fts3Init(db);
+}
+#endif
+
+#endif
+
+/************** End of fts3.c ************************************************/
+/************** Begin file fts3_expr.c ***************************************/
+/*
+** 2008 Nov 28
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This module contains code that implements a parser for fts3 query strings
+** (the right-hand argument to the MATCH operator). Because the supported
+** syntax is relatively simple, the whole tokenizer/parser system is
+** hand-coded.
+*/
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/*
+** By default, this module parses the legacy syntax that has been
+** traditionally used by fts3. Or, if SQLITE_ENABLE_FTS3_PARENTHESIS
+** is defined, then it uses the new syntax. The differences between
+** the new and the old syntaxes are:
+**
+**  a) The new syntax supports parenthesis. The old does not.
+**
+**  b) The new syntax supports the AND and NOT operators. The old does not.
+**
+**  c) The old syntax supports the "-" token qualifier. This is not
+**     supported by the new syntax (it is replaced by the NOT operator).
+**
+**  d) When using the old syntax, the OR operator has a greater precedence
+**     than an implicit AND. When using the new, both implicity and explicit
+**     AND operators have a higher precedence than OR.
+**
+** If compiled with SQLITE_TEST defined, then this module exports the
+** symbol "int sqlite3_fts3_enable_parentheses". Setting this variable
+** to zero causes the module to use the old syntax. If it is set to
+** non-zero the new syntax is activated. This is so both syntaxes can
+** be tested using a single build of testfixture.
+**
+** The following describes the syntax supported by the fts3 MATCH
+** operator in a similar format to that used by the lemon parser
+** generator. This module does not use actually lemon, it uses a
+** custom parser.
+**
+**   query ::= andexpr (OR andexpr)*.
+**
+**   andexpr ::= notexpr (AND? notexpr)*.
+**
+**   notexpr ::= nearexpr (NOT nearexpr|-TOKEN)*.
+**   notexpr ::= LP query RP.
+**
+**   nearexpr ::= phrase (NEAR distance_opt nearexpr)*.
+**
+**   distance_opt ::= .
+**   distance_opt ::= / INTEGER.
+**
+**   phrase ::= TOKEN.
+**   phrase ::= COLUMN:TOKEN.
+**   phrase ::= "TOKEN TOKEN TOKEN...".
+*/
+
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_fts3_enable_parentheses = 0;
+#else
+# ifdef SQLITE_ENABLE_FTS3_PARENTHESIS
+#  define sqlite3_fts3_enable_parentheses 1
+# else
+#  define sqlite3_fts3_enable_parentheses 0
+# endif
+#endif
+
+/*
+** Default span for NEAR operators.
+*/
+#define SQLITE_FTS3_DEFAULT_NEAR_PARAM 10
+
+
+typedef struct ParseContext ParseContext;
+struct ParseContext {
+  sqlite3_tokenizer *pTokenizer;      /* Tokenizer module */
+  const char **azCol;                 /* Array of column names for fts3 table */
+  int nCol;                           /* Number of entries in azCol[] */
+  int iDefaultCol;                    /* Default column to query */
+  sqlite3_context *pCtx;              /* Write error message here */
+  int nNest;                          /* Number of nested brackets */
+};
+
+/*
+** This function is equivalent to the standard isspace() function.
+**
+** The standard isspace() can be awkward to use safely, because although it
+** is defined to accept an argument of type int, its behaviour when passed
+** an integer that falls outside of the range of the unsigned char type
+** is undefined (and sometimes, "undefined" means segfault). This wrapper
+** is defined to accept an argument of type char, and always returns 0 for
+** any values that fall outside of the range of the unsigned char type (i.e.
+** negative values).
+*/
+static int fts3isspace(char c){
+  return (c&0x80)==0 ? isspace(c) : 0;
+}
+
+/*
+** Extract the next token from buffer z (length n) using the tokenizer
+** and other information (column names etc.) in pParse. Create an Fts3Expr
+** structure of type FTSQUERY_PHRASE containing a phrase consisting of this
+** single token and set *ppExpr to point to it. If the end of the buffer is
+** reached before a token is found, set *ppExpr to zero. It is the
+** responsibility of the caller to eventually deallocate the allocated
+** Fts3Expr structure (if any) by passing it to sqlite3_free().
+**
+** Return SQLITE_OK if successful, or SQLITE_NOMEM if a memory allocation
+** fails.
+*/
+static int getNextToken(
+  ParseContext *pParse,                   /* fts3 query parse context */
+  int iCol,                               /* Value for Fts3Phrase.iColumn */
+  const char *z, int n,                   /* Input string */
+  Fts3Expr **ppExpr,                      /* OUT: expression */
+  int *pnConsumed                         /* OUT: Number of bytes consumed */
+){
+  sqlite3_tokenizer *pTokenizer = pParse->pTokenizer;
+  sqlite3_tokenizer_module const *pModule = pTokenizer->pModule;
+  int rc;
+  sqlite3_tokenizer_cursor *pCursor;
+  Fts3Expr *pRet = 0;
+  int nConsumed = 0;
+
+  rc = pModule->xOpen(pTokenizer, z, n, &pCursor);
+  if( rc==SQLITE_OK ){
+    const char *zToken;
+    int nToken, iStart, iEnd, iPosition;
+    int nByte;                               /* total space to allocate */
+
+    pCursor->pTokenizer = pTokenizer;
+    rc = pModule->xNext(pCursor, &zToken, &nToken, &iStart, &iEnd, &iPosition);
+
+    if( rc==SQLITE_OK ){
+      nByte = sizeof(Fts3Expr) + sizeof(Fts3Phrase) + nToken;
+      pRet = (Fts3Expr *)sqlite3_malloc(nByte);
+      if( !pRet ){
+        rc = SQLITE_NOMEM;
       }else{
-        /* This case occurs when two terms (simple terms or phrases) are
-         * connected by a NEAR operator, span (nNear+1). i.e.
-         *
-         *     '"terrible company" NEAR widget'
-         */
-        DataBuffer one = {0, 0, 0};
-        DataBuffer two = {0, 0, 0};
-
-        DLWriter dlwriter2;
-        DLReader dr1 = {0, 0, 0, 0, 0};
-        DLReader dr2 = {0, 0, 0, 0, 0};
-
-        dlwInit(&dlwriter2, iType, &one);
-        posListPhraseMerge(&right, &left, nNear-3+nPhrase, 1, &dlwriter2);
-        dlwInit(&dlwriter2, iType, &two);
-        posListPhraseMerge(&left, &right, nNear-1, 0, &dlwriter2);
-
-        if( one.nData) dlrInit(&dr1, iType, one.pData, one.nData);
-        if( two.nData) dlrInit(&dr2, iType, two.pData, two.nData);
-
-        if( !dlrAtEnd(&dr1) || !dlrAtEnd(&dr2) ){
-          PLReader pr1 = {0};
-          PLReader pr2 = {0};
-
-          PLWriter plwriter;
-          plwInit(&plwriter, &writer, dlrDocid(dlrAtEnd(&dr1)?&dr2:&dr1));
-
-          if( one.nData ) plrInit(&pr1, &dr1);
-          if( two.nData ) plrInit(&pr2, &dr2);
-          while( !plrAtEnd(&pr1) || !plrAtEnd(&pr2) ){
-            int iCompare = plrCompare(&pr1, &pr2);
-            switch( iCompare ){
-              case -1:
-                plwCopy(&plwriter, &pr1);
-                plrStep(&pr1);
-                break;
-              case 1:
-                plwCopy(&plwriter, &pr2);
-                plrStep(&pr2);
-                break;
-              case 0:
-                plwCopy(&plwriter, &pr1);
-                plrStep(&pr1);
-                plrStep(&pr2);
-                break;
-            }
-          }
-          plwTerminate(&plwriter);
-        }
-        dataBufferDestroy(&one);
-        dataBufferDestroy(&two);
-      }
-      dlrStep(&left);
-      dlrStep(&right);
-    }
-  }
-
-  dlrDestroy(&left);
-  dlrDestroy(&right);
-  dlwDestroy(&writer);
-}
-
-/* We have two DL_DOCIDS doclists:  pLeft and pRight.
-** Write the intersection of these two doclists into pOut as a
-** DL_DOCIDS doclist.
-*/
-static void docListAndMerge(
-  const char *pLeft, int nLeft,
-  const char *pRight, int nRight,
-  DataBuffer *pOut      /* Write the combined doclist here */
-){
-  DLReader left, right;
-  DLWriter writer;
-
-  if( nLeft==0 || nRight==0 ) return;
-
-  dlrInit(&left, DL_DOCIDS, pLeft, nLeft);
-  dlrInit(&right, DL_DOCIDS, pRight, nRight);
-  dlwInit(&writer, DL_DOCIDS, pOut);
-
-  while( !dlrAtEnd(&left) && !dlrAtEnd(&right) ){
-    if( dlrDocid(&left)<dlrDocid(&right) ){
-      dlrStep(&left);
-    }else if( dlrDocid(&right)<dlrDocid(&left) ){
-      dlrStep(&right);
-    }else{
-      dlwAdd(&writer, dlrDocid(&left));
-      dlrStep(&left);
-      dlrStep(&right);
-    }
-  }
-
-  dlrDestroy(&left);
-  dlrDestroy(&right);
-  dlwDestroy(&writer);
-}
-
-/* We have two DL_DOCIDS doclists:  pLeft and pRight.
-** Write the union of these two doclists into pOut as a
-** DL_DOCIDS doclist.
-*/
-static void docListOrMerge(
-  const char *pLeft, int nLeft,
-  const char *pRight, int nRight,
-  DataBuffer *pOut      /* Write the combined doclist here */
-){
-  DLReader left, right;
-  DLWriter writer;
-
-  if( nLeft==0 ){
-    if( nRight!=0 ) dataBufferAppend(pOut, pRight, nRight);
-    return;
-  }
-  if( nRight==0 ){
-    dataBufferAppend(pOut, pLeft, nLeft);
-    return;
-  }
-
-  dlrInit(&left, DL_DOCIDS, pLeft, nLeft);
-  dlrInit(&right, DL_DOCIDS, pRight, nRight);
-  dlwInit(&writer, DL_DOCIDS, pOut);
-
-  while( !dlrAtEnd(&left) || !dlrAtEnd(&right) ){
-    if( dlrAtEnd(&right) ){
-      dlwAdd(&writer, dlrDocid(&left));
-      dlrStep(&left);
-    }else if( dlrAtEnd(&left) ){
-      dlwAdd(&writer, dlrDocid(&right));
-      dlrStep(&right);
-    }else if( dlrDocid(&left)<dlrDocid(&right) ){
-      dlwAdd(&writer, dlrDocid(&left));
-      dlrStep(&left);
-    }else if( dlrDocid(&right)<dlrDocid(&left) ){
-      dlwAdd(&writer, dlrDocid(&right));
-      dlrStep(&right);
-    }else{
-      dlwAdd(&writer, dlrDocid(&left));
-      dlrStep(&left);
-      dlrStep(&right);
-    }
-  }
-
-  dlrDestroy(&left);
-  dlrDestroy(&right);
-  dlwDestroy(&writer);
-}
-
-/* We have two DL_DOCIDS doclists:  pLeft and pRight.
-** Write into pOut as DL_DOCIDS doclist containing all documents that
-** occur in pLeft but not in pRight.
-*/
-static void docListExceptMerge(
-  const char *pLeft, int nLeft,
-  const char *pRight, int nRight,
-  DataBuffer *pOut      /* Write the combined doclist here */
-){
-  DLReader left, right;
-  DLWriter writer;
-
-  if( nLeft==0 ) return;
-  if( nRight==0 ){
-    dataBufferAppend(pOut, pLeft, nLeft);
-    return;
-  }
-
-  dlrInit(&left, DL_DOCIDS, pLeft, nLeft);
-  dlrInit(&right, DL_DOCIDS, pRight, nRight);
-  dlwInit(&writer, DL_DOCIDS, pOut);
-
-  while( !dlrAtEnd(&left) ){
-    while( !dlrAtEnd(&right) && dlrDocid(&right)<dlrDocid(&left) ){
-      dlrStep(&right);
-    }
-    if( dlrAtEnd(&right) || dlrDocid(&left)<dlrDocid(&right) ){
-      dlwAdd(&writer, dlrDocid(&left));
-    }
-    dlrStep(&left);
-  }
-
-  dlrDestroy(&left);
-  dlrDestroy(&right);
-  dlwDestroy(&writer);
-}
-
-static char *string_dup_n(const char *s, int n){
-  char *str = sqlite3_malloc(n + 1);
-  memcpy(str, s, n);
-  str[n] = '\0';
-  return str;
-}
-
-/* Duplicate a string; the caller must free() the returned string.
- * (We don't use strdup() since it is not part of the standard C library and
- * may not be available everywhere.) */
-static char *string_dup(const char *s){
-  return string_dup_n(s, strlen(s));
-}
-
-/* Format a string, replacing each occurrence of the % character with
- * zDb.zName.  This may be more convenient than sqlite_mprintf()
- * when one string is used repeatedly in a format string.
- * The caller must free() the returned string. */
-static char *string_format(const char *zFormat,
-                           const char *zDb, const char *zName){
-  const char *p;
-  size_t len = 0;
-  size_t nDb = strlen(zDb);
-  size_t nName = strlen(zName);
-  size_t nFullTableName = nDb+1+nName;
-  char *result;
-  char *r;
-
-  /* first compute length needed */
-  for(p = zFormat ; *p ; ++p){
-    len += (*p=='%' ? nFullTableName : 1);
-  }
-  len += 1;  /* for null terminator */
-
-  r = result = sqlite3_malloc(len);
-  for(p = zFormat; *p; ++p){
-    if( *p=='%' ){
-      memcpy(r, zDb, nDb);
-      r += nDb;
-      *r++ = '.';
-      memcpy(r, zName, nName);
-      r += nName;
-    } else {
-      *r++ = *p;
-    }
-  }
-  *r++ = '\0';
-  assert( r == result + len );
-  return result;
-}
-
-static int sql_exec(sqlite3 *db, const char *zDb, const char *zName,
-                    const char *zFormat){
-  char *zCommand = string_format(zFormat, zDb, zName);
-  int rc;
-  FTSTRACE(("FTS3 sql: %s\n", zCommand));
-  rc = sqlite3_exec(db, zCommand, NULL, 0, NULL);
-  sqlite3_free(zCommand);
-  return rc;
-}
-
-static int sql_prepare(sqlite3 *db, const char *zDb, const char *zName,
-                       sqlite3_stmt **ppStmt, const char *zFormat){
-  char *zCommand = string_format(zFormat, zDb, zName);
-  int rc;
-  FTSTRACE(("FTS3 prepare: %s\n", zCommand));
-  rc = sqlite3_prepare_v2(db, zCommand, -1, ppStmt, NULL);
-  sqlite3_free(zCommand);
-  return rc;
-}
-
-/* end utility functions */
-
-/* Forward reference */
-typedef struct fulltext_vtab fulltext_vtab;
-
-/*
-** An instance of the following structure keeps track of generated
-** matching-word offset information and snippets.
-*/
-typedef struct Snippet {
-  int nMatch;     /* Total number of matches */
-  int nAlloc;     /* Space allocated for aMatch[] */
-  struct snippetMatch { /* One entry for each matching term */
-    char snStatus;       /* Status flag for use while constructing snippets */
-    short int iCol;      /* The column that contains the match */
-    short int iTerm;     /* The index in Query.pTerms[] of the matching term */
-    int iToken;          /* The index of the matching document token */
-    short int nByte;     /* Number of bytes in the term */
-    int iStart;          /* The offset to the first character of the term */
-  } *aMatch;      /* Points to space obtained from malloc */
-  char *zOffset;  /* Text rendering of aMatch[] */
-  int nOffset;    /* strlen(zOffset) */
-  char *zSnippet; /* Snippet text */
-  int nSnippet;   /* strlen(zSnippet) */
-} Snippet;
-
-
-typedef enum QueryType {
-  QUERY_GENERIC,   /* table scan */
-  QUERY_DOCID,     /* lookup by docid */
-  QUERY_FULLTEXT   /* QUERY_FULLTEXT + [i] is a full-text search for column i*/
-} QueryType;
-
-typedef enum fulltext_statement {
-  CONTENT_INSERT_STMT,
-  CONTENT_SELECT_STMT,
-  CONTENT_UPDATE_STMT,
-  CONTENT_DELETE_STMT,
-  CONTENT_EXISTS_STMT,
-
-  BLOCK_INSERT_STMT,
-  BLOCK_SELECT_STMT,
-  BLOCK_DELETE_STMT,
-  BLOCK_DELETE_ALL_STMT,
-
-  SEGDIR_MAX_INDEX_STMT,
-  SEGDIR_SET_STMT,
-  SEGDIR_SELECT_LEVEL_STMT,
-  SEGDIR_SPAN_STMT,
-  SEGDIR_DELETE_STMT,
-  SEGDIR_SELECT_SEGMENT_STMT,
-  SEGDIR_SELECT_ALL_STMT,
-  SEGDIR_DELETE_ALL_STMT,
-  SEGDIR_COUNT_STMT,
-
-  MAX_STMT                     /* Always at end! */
-} fulltext_statement;
-
-/* These must exactly match the enum above. */
-/* TODO(shess): Is there some risk that a statement will be used in two
-** cursors at once, e.g.  if a query joins a virtual table to itself?
-** If so perhaps we should move some of these to the cursor object.
-*/
-static const char *const fulltext_zStatement[MAX_STMT] = {
-  /* CONTENT_INSERT */ NULL,  /* generated in contentInsertStatement() */
-  /* CONTENT_SELECT */ NULL,  /* generated in contentSelectStatement() */
-  /* CONTENT_UPDATE */ NULL,  /* generated in contentUpdateStatement() */
-  /* CONTENT_DELETE */ "delete from %_content where docid = ?",
-  /* CONTENT_EXISTS */ "select docid from %_content limit 1",
-
-  /* BLOCK_INSERT */
-  "insert into %_segments (blockid, block) values (null, ?)",
-  /* BLOCK_SELECT */ "select block from %_segments where blockid = ?",
-  /* BLOCK_DELETE */ "delete from %_segments where blockid between ? and ?",
-  /* BLOCK_DELETE_ALL */ "delete from %_segments",
-
-  /* SEGDIR_MAX_INDEX */ "select max(idx) from %_segdir where level = ?",
-  /* SEGDIR_SET */ "insert into %_segdir values (?, ?, ?, ?, ?, ?)",
-  /* SEGDIR_SELECT_LEVEL */
-  "select start_block, leaves_end_block, root from %_segdir "
-  " where level = ? order by idx",
-  /* SEGDIR_SPAN */
-  "select min(start_block), max(end_block) from %_segdir "
-  " where level = ? and start_block <> 0",
-  /* SEGDIR_DELETE */ "delete from %_segdir where level = ?",
-
-  /* NOTE(shess): The first three results of the following two
-  ** statements must match.
-  */
-  /* SEGDIR_SELECT_SEGMENT */
-  "select start_block, leaves_end_block, root from %_segdir "
-  " where level = ? and idx = ?",
-  /* SEGDIR_SELECT_ALL */
-  "select start_block, leaves_end_block, root from %_segdir "
-  " order by level desc, idx asc",
-  /* SEGDIR_DELETE_ALL */ "delete from %_segdir",
-  /* SEGDIR_COUNT */ "select count(*), ifnull(max(level),0) from %_segdir",
-};
-
-/*
-** A connection to a fulltext index is an instance of the following
-** structure.  The xCreate and xConnect methods create an instance
-** of this structure and xDestroy and xDisconnect free that instance.
-** All other methods receive a pointer to the structure as one of their
-** arguments.
-*/
-struct fulltext_vtab {
-  sqlite3_vtab base;               /* Base class used by SQLite core */
-  sqlite3 *db;                     /* The database connection */
-  const char *zDb;                 /* logical database name */
-  const char *zName;               /* virtual table name */
-  int nColumn;                     /* number of columns in virtual table */
-  char **azColumn;                 /* column names.  malloced */
-  char **azContentColumn;          /* column names in content table; malloced */
-  sqlite3_tokenizer *pTokenizer;   /* tokenizer for inserts and queries */
-
-  /* Precompiled statements which we keep as long as the table is
-  ** open.
-  */
-  sqlite3_stmt *pFulltextStatements[MAX_STMT];
-
-  /* Precompiled statements used for segment merges.  We run a
-  ** separate select across the leaf level of each tree being merged.
-  */
-  sqlite3_stmt *pLeafSelectStmts[MERGE_COUNT];
-  /* The statement used to prepare pLeafSelectStmts. */
-#define LEAF_SELECT \
-  "select block from %_segments where blockid between ? and ? order by blockid"
-
-  /* These buffer pending index updates during transactions.
-  ** nPendingData estimates the memory size of the pending data.  It
-  ** doesn't include the hash-bucket overhead, nor any malloc
-  ** overhead.  When nPendingData exceeds kPendingThreshold, the
-  ** buffer is flushed even before the transaction closes.
-  ** pendingTerms stores the data, and is only valid when nPendingData
-  ** is >=0 (nPendingData<0 means pendingTerms has not been
-  ** initialized).  iPrevDocid is the last docid written, used to make
-  ** certain we're inserting in sorted order.
-  */
-  int nPendingData;
-#define kPendingThreshold (1*1024*1024)
-  sqlite_int64 iPrevDocid;
-  fts3Hash pendingTerms;
-};
-
-/*
-** When the core wants to do a query, it create a cursor using a
-** call to xOpen.  This structure is an instance of a cursor.  It
-** is destroyed by xClose.
-*/
-typedef struct fulltext_cursor {
-  sqlite3_vtab_cursor base;        /* Base class used by SQLite core */
-  QueryType iCursorType;           /* Copy of sqlite3_index_info.idxNum */
-  sqlite3_stmt *pStmt;             /* Prepared statement in use by the cursor */
-  int eof;                         /* True if at End Of Results */
-  Fts3Expr *pExpr;                 /* Parsed MATCH query string */
-  Snippet snippet;                 /* Cached snippet for the current row */
-  int iColumn;                     /* Column being searched */
-  DataBuffer result;               /* Doclist results from fulltextQuery */
-  DLReader reader;                 /* Result reader if result not empty */
-} fulltext_cursor;
-
-static fulltext_vtab *cursor_vtab(fulltext_cursor *c){
-  return (fulltext_vtab *) c->base.pVtab;
-}
-
-static const sqlite3_module fts3Module;   /* forward declaration */
-
-/* Return a dynamically generated statement of the form
- *   insert into %_content (docid, ...) values (?, ...)
- */
-static const char *contentInsertStatement(fulltext_vtab *v){
-  StringBuffer sb;
-  int i;
-
-  initStringBuffer(&sb);
-  append(&sb, "insert into %_content (docid, ");
-  appendList(&sb, v->nColumn, v->azContentColumn);
-  append(&sb, ") values (?");
-  for(i=0; i<v->nColumn; ++i)
-    append(&sb, ", ?");
-  append(&sb, ")");
-  return stringBufferData(&sb);
-}
-
-/* Return a dynamically generated statement of the form
- *   select <content columns> from %_content where docid = ?
- */
-static const char *contentSelectStatement(fulltext_vtab *v){
-  StringBuffer sb;
-  initStringBuffer(&sb);
-  append(&sb, "SELECT ");
-  appendList(&sb, v->nColumn, v->azContentColumn);
-  append(&sb, " FROM %_content WHERE docid = ?");
-  return stringBufferData(&sb);
-}
-
-/* Return a dynamically generated statement of the form
- *   update %_content set [col_0] = ?, [col_1] = ?, ...
- *                    where docid = ?
- */
-static const char *contentUpdateStatement(fulltext_vtab *v){
-  StringBuffer sb;
-  int i;
-
-  initStringBuffer(&sb);
-  append(&sb, "update %_content set ");
-  for(i=0; i<v->nColumn; ++i) {
-    if( i>0 ){
-      append(&sb, ", ");
-    }
-    append(&sb, v->azContentColumn[i]);
-    append(&sb, " = ?");
-  }
-  append(&sb, " where docid = ?");
-  return stringBufferData(&sb);
-}
-
-/* Puts a freshly-prepared statement determined by iStmt in *ppStmt.
-** If the indicated statement has never been prepared, it is prepared
-** and cached, otherwise the cached version is reset.
-*/
-static int sql_get_statement(fulltext_vtab *v, fulltext_statement iStmt,
-                             sqlite3_stmt **ppStmt){
-  assert( iStmt<MAX_STMT );
-  if( v->pFulltextStatements[iStmt]==NULL ){
-    const char *zStmt;
-    int rc;
-    switch( iStmt ){
-      case CONTENT_INSERT_STMT:
-        zStmt = contentInsertStatement(v); break;
-      case CONTENT_SELECT_STMT:
-        zStmt = contentSelectStatement(v); break;
-      case CONTENT_UPDATE_STMT:
-        zStmt = contentUpdateStatement(v); break;
-      default:
-        zStmt = fulltext_zStatement[iStmt];
-    }
-    rc = sql_prepare(v->db, v->zDb, v->zName, &v->pFulltextStatements[iStmt],
-                         zStmt);
-    if( zStmt != fulltext_zStatement[iStmt]) sqlite3_free((void *) zStmt);
-    if( rc!=SQLITE_OK ) return rc;
-  } else {
-    int rc = sqlite3_reset(v->pFulltextStatements[iStmt]);
-    if( rc!=SQLITE_OK ) return rc;
-  }
-
-  *ppStmt = v->pFulltextStatements[iStmt];
-  return SQLITE_OK;
-}
-
-/* Like sqlite3_step(), but convert SQLITE_DONE to SQLITE_OK and
-** SQLITE_ROW to SQLITE_ERROR.  Useful for statements like UPDATE,
-** where we expect no results.
-*/
-static int sql_single_step(sqlite3_stmt *s){
-  int rc = sqlite3_step(s);
-  return (rc==SQLITE_DONE) ? SQLITE_OK : rc;
-}
-
-/* Like sql_get_statement(), but for special replicated LEAF_SELECT
-** statements.  idx -1 is a special case for an uncached version of
-** the statement (used in the optimize implementation).
-*/
-/* TODO(shess) Write version for generic statements and then share
-** that between the cached-statement functions.
-*/
-static int sql_get_leaf_statement(fulltext_vtab *v, int idx,
-                                  sqlite3_stmt **ppStmt){
-  assert( idx>=-1 && idx<MERGE_COUNT );
-  if( idx==-1 ){
-    return sql_prepare(v->db, v->zDb, v->zName, ppStmt, LEAF_SELECT);
-  }else if( v->pLeafSelectStmts[idx]==NULL ){
-    int rc = sql_prepare(v->db, v->zDb, v->zName, &v->pLeafSelectStmts[idx],
-                         LEAF_SELECT);
-    if( rc!=SQLITE_OK ) return rc;
-  }else{
-    int rc = sqlite3_reset(v->pLeafSelectStmts[idx]);
-    if( rc!=SQLITE_OK ) return rc;
-  }
-
-  *ppStmt = v->pLeafSelectStmts[idx];
-  return SQLITE_OK;
-}
-
-/* insert into %_content (docid, ...) values ([docid], [pValues])
-** If the docid contains SQL NULL, then a unique docid will be
-** generated.
-*/
-static int content_insert(fulltext_vtab *v, sqlite3_value *docid,
-                          sqlite3_value **pValues){
-  sqlite3_stmt *s;
-  int i;
-  int rc = sql_get_statement(v, CONTENT_INSERT_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_value(s, 1, docid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  for(i=0; i<v->nColumn; ++i){
-    rc = sqlite3_bind_value(s, 2+i, pValues[i]);
-    if( rc!=SQLITE_OK ) return rc;
-  }
-
-  return sql_single_step(s);
-}
-
-/* update %_content set col0 = pValues[0], col1 = pValues[1], ...
- *                  where docid = [iDocid] */
-static int content_update(fulltext_vtab *v, sqlite3_value **pValues,
-                          sqlite_int64 iDocid){
-  sqlite3_stmt *s;
-  int i;
-  int rc = sql_get_statement(v, CONTENT_UPDATE_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  for(i=0; i<v->nColumn; ++i){
-    rc = sqlite3_bind_value(s, 1+i, pValues[i]);
-    if( rc!=SQLITE_OK ) return rc;
-  }
-
-  rc = sqlite3_bind_int64(s, 1+v->nColumn, iDocid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  return sql_single_step(s);
-}
-
-static void freeStringArray(int nString, const char **pString){
-  int i;
-
-  for (i=0 ; i < nString ; ++i) {
-    if( pString[i]!=NULL ) sqlite3_free((void *) pString[i]);
-  }
-  sqlite3_free((void *) pString);
-}
-
-/* select * from %_content where docid = [iDocid]
- * The caller must delete the returned array and all strings in it.
- * null fields will be NULL in the returned array.
- *
- * TODO: Perhaps we should return pointer/length strings here for consistency
- * with other code which uses pointer/length. */
-static int content_select(fulltext_vtab *v, sqlite_int64 iDocid,
-                          const char ***pValues){
-  sqlite3_stmt *s;
-  const char **values;
-  int i;
-  int rc;
-
-  *pValues = NULL;
-
-  rc = sql_get_statement(v, CONTENT_SELECT_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int64(s, 1, iDocid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_step(s);
-  if( rc!=SQLITE_ROW ) return rc;
-
-  values = (const char **) sqlite3_malloc(v->nColumn * sizeof(const char *));
-  for(i=0; i<v->nColumn; ++i){
-    if( sqlite3_column_type(s, i)==SQLITE_NULL ){
-      values[i] = NULL;
-    }else{
-      values[i] = string_dup((char*)sqlite3_column_text(s, i));
-    }
-  }
-
-  /* We expect only one row.  We must execute another sqlite3_step()
-   * to complete the iteration; otherwise the table will remain locked. */
-  rc = sqlite3_step(s);
+        memset(pRet, 0, nByte);
+        pRet->eType = FTSQUERY_PHRASE;
+        pRet->pPhrase = (Fts3Phrase *)&pRet[1];
+        pRet->pPhrase->nToken = 1;
+        pRet->pPhrase->iColumn = iCol;
+        pRet->pPhrase->aToken[0].n = nToken;
+        pRet->pPhrase->aToken[0].z = (char *)&pRet->pPhrase[1];
+        memcpy(pRet->pPhrase->aToken[0].z, zToken, nToken);
+
+        if( iEnd<n && z[iEnd]=='*' ){
+          pRet->pPhrase->aToken[0].isPrefix = 1;
+          iEnd++;
+        }
+        if( !sqlite3_fts3_enable_parentheses && iStart>0 && z[iStart-1]=='-' ){
+          pRet->pPhrase->isNot = 1;
+        }
+      }
+      nConsumed = iEnd;
+    }
+
+    pModule->xClose(pCursor);
+  }
+
+  *pnConsumed = nConsumed;
+  *ppExpr = pRet;
+  return rc;
+}
+
+
+/*
+** Enlarge a memory allocation.  If an out-of-memory allocation occurs,
+** then free the old allocation.
+*/
+void *fts3ReallocOrFree(void *pOrig, int nNew){
+  void *pRet = sqlite3_realloc(pOrig, nNew);
+  if( !pRet ){
+    sqlite3_free(pOrig);
+  }
+  return pRet;
+}
+
+/*
+** Buffer zInput, length nInput, contains the contents of a quoted string
+** that appeared as part of an fts3 query expression. Neither quote character
+** is included in the buffer. This function attempts to tokenize the entire
+** input buffer and create an Fts3Expr structure of type FTSQUERY_PHRASE
+** containing the results.
+**
+** If successful, SQLITE_OK is returned and *ppExpr set to point at the
+** allocated Fts3Expr structure. Otherwise, either SQLITE_NOMEM (out of memory
+** error) or SQLITE_ERROR (tokenization error) is returned and *ppExpr set
+** to 0.
+*/
+static int getNextString(
+  ParseContext *pParse,                   /* fts3 query parse context */
+  const char *zInput, int nInput,         /* Input string */
+  Fts3Expr **ppExpr                       /* OUT: expression */
+){
+  sqlite3_tokenizer *pTokenizer = pParse->pTokenizer;
+  sqlite3_tokenizer_module const *pModule = pTokenizer->pModule;
+  int rc;
+  Fts3Expr *p = 0;
+  sqlite3_tokenizer_cursor *pCursor = 0;
+  char *zTemp = 0;
+  int nTemp = 0;
+
+  rc = pModule->xOpen(pTokenizer, zInput, nInput, &pCursor);
+  if( rc==SQLITE_OK ){
+    int ii;
+    pCursor->pTokenizer = pTokenizer;
+    for(ii=0; rc==SQLITE_OK; ii++){
+      const char *zToken;
+      int nToken, iBegin, iEnd, iPos;
+      rc = pModule->xNext(pCursor, &zToken, &nToken, &iBegin, &iEnd, &iPos);
+      if( rc==SQLITE_OK ){
+        int nByte = sizeof(Fts3Expr) + sizeof(Fts3Phrase);
+        p = fts3ReallocOrFree(p, nByte+ii*sizeof(struct PhraseToken));
+        zTemp = fts3ReallocOrFree(zTemp, nTemp + nToken);
+        if( !p || !zTemp ){
+          goto no_mem;
+        }
+        if( ii==0 ){
+          memset(p, 0, nByte);
+          p->pPhrase = (Fts3Phrase *)&p[1];
+        }
+        p->pPhrase = (Fts3Phrase *)&p[1];
+        p->pPhrase->nToken = ii+1;
+        p->pPhrase->aToken[ii].n = nToken;
+        memcpy(&zTemp[nTemp], zToken, nToken);
+        nTemp += nToken;
+        if( iEnd<nInput && zInput[iEnd]=='*' ){
+          p->pPhrase->aToken[ii].isPrefix = 1;
+        }else{
+          p->pPhrase->aToken[ii].isPrefix = 0;
+        }
+      }
+    }
+
+    pModule->xClose(pCursor);
+    pCursor = 0;
+  }
+
   if( rc==SQLITE_DONE ){
-    *pValues = values;
-    return SQLITE_OK;
-  }
-
-  freeStringArray(v->nColumn, values);
-  return rc;
-}
-
-/* delete from %_content where docid = [iDocid ] */
-static int content_delete(fulltext_vtab *v, sqlite_int64 iDocid){
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, CONTENT_DELETE_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int64(s, 1, iDocid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  return sql_single_step(s);
-}
-
-/* Returns SQLITE_ROW if any rows exist in %_content, SQLITE_DONE if
-** no rows exist, and any error in case of failure.
-*/
-static int content_exists(fulltext_vtab *v){
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, CONTENT_EXISTS_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_step(s);
-  if( rc!=SQLITE_ROW ) return rc;
-
-  /* We expect only one row.  We must execute another sqlite3_step()
-   * to complete the iteration; otherwise the table will remain locked. */
-  rc = sqlite3_step(s);
-  if( rc==SQLITE_DONE ) return SQLITE_ROW;
-  if( rc==SQLITE_ROW ) return SQLITE_ERROR;
-  return rc;
-}
-
-/* insert into %_segments values ([pData])
-**   returns assigned blockid in *piBlockid
-*/
-static int block_insert(fulltext_vtab *v, const char *pData, int nData,
-                        sqlite_int64 *piBlockid){
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, BLOCK_INSERT_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_blob(s, 1, pData, nData, SQLITE_STATIC);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_step(s);
-  if( rc==SQLITE_ROW ) return SQLITE_ERROR;
-  if( rc!=SQLITE_DONE ) return rc;
-
-  /* blockid column is an alias for rowid. */
-  *piBlockid = sqlite3_last_insert_rowid(v->db);
-  return SQLITE_OK;
-}
-
-/* delete from %_segments
-**   where blockid between [iStartBlockid] and [iEndBlockid]
-**
-** Deletes the range of blocks, inclusive, used to delete the blocks
-** which form a segment.
-*/
-static int block_delete(fulltext_vtab *v,
-                        sqlite_int64 iStartBlockid, sqlite_int64 iEndBlockid){
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, BLOCK_DELETE_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int64(s, 1, iStartBlockid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int64(s, 2, iEndBlockid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  return sql_single_step(s);
-}
-
-/* Returns SQLITE_ROW with *pidx set to the maximum segment idx found
-** at iLevel.  Returns SQLITE_DONE if there are no segments at
-** iLevel.  Otherwise returns an error.
-*/
-static int segdir_max_index(fulltext_vtab *v, int iLevel, int *pidx){
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, SEGDIR_MAX_INDEX_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int(s, 1, iLevel);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_step(s);
-  /* Should always get at least one row due to how max() works. */
-  if( rc==SQLITE_DONE ) return SQLITE_DONE;
-  if( rc!=SQLITE_ROW ) return rc;
-
-  /* NULL means that there were no inputs to max(). */
-  if( SQLITE_NULL==sqlite3_column_type(s, 0) ){
-    rc = sqlite3_step(s);
-    if( rc==SQLITE_ROW ) return SQLITE_ERROR;
-    return rc;
-  }
-
-  *pidx = sqlite3_column_int(s, 0);
-
-  /* We expect only one row.  We must execute another sqlite3_step()
-   * to complete the iteration; otherwise the table will remain locked. */
-  rc = sqlite3_step(s);
-  if( rc==SQLITE_ROW ) return SQLITE_ERROR;
-  if( rc!=SQLITE_DONE ) return rc;
-  return SQLITE_ROW;
-}
-
-/* insert into %_segdir values (
-**   [iLevel], [idx],
-**   [iStartBlockid], [iLeavesEndBlockid], [iEndBlockid],
-**   [pRootData]
-** )
-*/
-static int segdir_set(fulltext_vtab *v, int iLevel, int idx,
-                      sqlite_int64 iStartBlockid,
-                      sqlite_int64 iLeavesEndBlockid,
-                      sqlite_int64 iEndBlockid,
-                      const char *pRootData, int nRootData){
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, SEGDIR_SET_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int(s, 1, iLevel);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int(s, 2, idx);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int64(s, 3, iStartBlockid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int64(s, 4, iLeavesEndBlockid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int64(s, 5, iEndBlockid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_blob(s, 6, pRootData, nRootData, SQLITE_STATIC);
-  if( rc!=SQLITE_OK ) return rc;
-
-  return sql_single_step(s);
-}
-
-/* Queries %_segdir for the block span of the segments in level
-** iLevel.  Returns SQLITE_DONE if there are no blocks for iLevel,
-** SQLITE_ROW if there are blocks, else an error.
-*/
-static int segdir_span(fulltext_vtab *v, int iLevel,
-                       sqlite_int64 *piStartBlockid,
-                       sqlite_int64 *piEndBlockid){
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, SEGDIR_SPAN_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int(s, 1, iLevel);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_step(s);
-  if( rc==SQLITE_DONE ) return SQLITE_DONE;  /* Should never happen */
-  if( rc!=SQLITE_ROW ) return rc;
-
-  /* This happens if all segments at this level are entirely inline. */
-  if( SQLITE_NULL==sqlite3_column_type(s, 0) ){
-    /* We expect only one row.  We must execute another sqlite3_step()
-     * to complete the iteration; otherwise the table will remain locked. */
-    int rc2 = sqlite3_step(s);
-    if( rc2==SQLITE_ROW ) return SQLITE_ERROR;
-    return rc2;
-  }
-
-  *piStartBlockid = sqlite3_column_int64(s, 0);
-  *piEndBlockid = sqlite3_column_int64(s, 1);
-
-  /* We expect only one row.  We must execute another sqlite3_step()
-   * to complete the iteration; otherwise the table will remain locked. */
-  rc = sqlite3_step(s);
-  if( rc==SQLITE_ROW ) return SQLITE_ERROR;
-  if( rc!=SQLITE_DONE ) return rc;
-  return SQLITE_ROW;
-}
-
-/* Delete the segment blocks and segment directory records for all
-** segments at iLevel.
-*/
-static int segdir_delete(fulltext_vtab *v, int iLevel){
-  sqlite3_stmt *s;
-  sqlite_int64 iStartBlockid, iEndBlockid;
-  int rc = segdir_span(v, iLevel, &iStartBlockid, &iEndBlockid);
-  if( rc!=SQLITE_ROW && rc!=SQLITE_DONE ) return rc;
-
-  if( rc==SQLITE_ROW ){
-    rc = block_delete(v, iStartBlockid, iEndBlockid);
-    if( rc!=SQLITE_OK ) return rc;
-  }
-
-  /* Delete the segment directory itself. */
-  rc = sql_get_statement(v, SEGDIR_DELETE_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int64(s, 1, iLevel);
-  if( rc!=SQLITE_OK ) return rc;
-
-  return sql_single_step(s);
-}
-
-/* Delete entire fts index, SQLITE_OK on success, relevant error on
-** failure.
-*/
-static int segdir_delete_all(fulltext_vtab *v){
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, SEGDIR_DELETE_ALL_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sql_single_step(s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sql_get_statement(v, BLOCK_DELETE_ALL_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  return sql_single_step(s);
-}
-
-/* Returns SQLITE_OK with *pnSegments set to the number of entries in
-** %_segdir and *piMaxLevel set to the highest level which has a
-** segment.  Otherwise returns the SQLite error which caused failure.
-*/
-static int segdir_count(fulltext_vtab *v, int *pnSegments, int *piMaxLevel){
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, SEGDIR_COUNT_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_step(s);
-  /* TODO(shess): This case should not be possible?  Should stronger
-  ** measures be taken if it happens?
-  */
-  if( rc==SQLITE_DONE ){
-    *pnSegments = 0;
-    *piMaxLevel = 0;
-    return SQLITE_OK;
-  }
-  if( rc!=SQLITE_ROW ) return rc;
-
-  *pnSegments = sqlite3_column_int(s, 0);
-  *piMaxLevel = sqlite3_column_int(s, 1);
-
-  /* We expect only one row.  We must execute another sqlite3_step()
-   * to complete the iteration; otherwise the table will remain locked. */
-  rc = sqlite3_step(s);
-  if( rc==SQLITE_DONE ) return SQLITE_OK;
-  if( rc==SQLITE_ROW ) return SQLITE_ERROR;
-  return rc;
-}
-
-/* TODO(shess) clearPendingTerms() is far down the file because
-** writeZeroSegment() is far down the file because LeafWriter is far
-** down the file.  Consider refactoring the code to move the non-vtab
-** code above the vtab code so that we don't need this forward
-** reference.
-*/
-static int clearPendingTerms(fulltext_vtab *v);
-
-/*
-** Free the memory used to contain a fulltext_vtab structure.
-*/
-static void fulltext_vtab_destroy(fulltext_vtab *v){
-  int iStmt, i;
-
-  FTSTRACE(("FTS3 Destroy %p\n", v));
-  for( iStmt=0; iStmt<MAX_STMT; iStmt++ ){
-    if( v->pFulltextStatements[iStmt]!=NULL ){
-      sqlite3_finalize(v->pFulltextStatements[iStmt]);
-      v->pFulltextStatements[iStmt] = NULL;
-    }
-  }
-
-  for( i=0; i<MERGE_COUNT; i++ ){
-    if( v->pLeafSelectStmts[i]!=NULL ){
-      sqlite3_finalize(v->pLeafSelectStmts[i]);
-      v->pLeafSelectStmts[i] = NULL;
-    }
-  }
-
-  if( v->pTokenizer!=NULL ){
-    v->pTokenizer->pModule->xDestroy(v->pTokenizer);
-    v->pTokenizer = NULL;
-  }
-
-  clearPendingTerms(v);
-
-  sqlite3_free(v->azColumn);
-  for(i = 0; i < v->nColumn; ++i) {
-    sqlite3_free(v->azContentColumn[i]);
-  }
-  sqlite3_free(v->azContentColumn);
-  sqlite3_free(v);
-}
-
-/*
-** Token types for parsing the arguments to xConnect or xCreate.
-*/
-#define TOKEN_EOF         0    /* End of file */
-#define TOKEN_SPACE       1    /* Any kind of whitespace */
-#define TOKEN_ID          2    /* An identifier */
-#define TOKEN_STRING      3    /* A string literal */
-#define TOKEN_PUNCT       4    /* A single punctuation character */
-
-/*
-** If X is a character that can be used in an identifier then
-** ftsIdChar(X) will be true.  Otherwise it is false.
-**
-** For ASCII, any character with the high-order bit set is
-** allowed in an identifier.  For 7-bit characters,
-** isFtsIdChar[X] must be 1.
-**
-** Ticket #1066.  the SQL standard does not allow '$' in the
-** middle of identfiers.  But many SQL implementations do.
-** SQLite will allow '$' in identifiers for compatibility.
-** But the feature is undocumented.
-*/
-static const char isFtsIdChar[] = {
-/* x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 xA xB xC xD xE xF */
-    0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 2x */
-    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,  /* 3x */
-    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 4x */
-    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1,  /* 5x */
-    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 6x */
-    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0,  /* 7x */
-};
-#define ftsIdChar(C)  (((c=C)&0x80)!=0 || (c>0x1f && isFtsIdChar[c-0x20]))
-
-
-/*
-** Return the length of the token that begins at z[0].
-** Store the token type in *tokenType before returning.
-*/
-static int ftsGetToken(const char *z, int *tokenType){
-  int i, c;
-  switch( *z ){
-    case 0: {
-      *tokenType = TOKEN_EOF;
-      return 0;
-    }
-    case ' ': case '\t': case '\n': case '\f': case '\r': {
-      for(i=1; safe_isspace(z[i]); i++){}
-      *tokenType = TOKEN_SPACE;
-      return i;
-    }
-    case '`':
-    case '\'':
-    case '"': {
-      int delim = z[0];
-      for(i=1; (c=z[i])!=0; i++){
-        if( c==delim ){
-          if( z[i+1]==delim ){
-            i++;
-          }else{
-            break;
+    int jj;
+    char *zNew;
+    int nNew = 0;
+    int nByte = sizeof(Fts3Expr) + sizeof(Fts3Phrase);
+    nByte += (p?(p->pPhrase->nToken-1):0) * sizeof(struct PhraseToken);
+    p = fts3ReallocOrFree(p, nByte + nTemp);
+    if( !p ){
+      goto no_mem;
+    }
+    if( zTemp ){
+      zNew = &(((char *)p)[nByte]);
+      memcpy(zNew, zTemp, nTemp);
+    }else{
+      memset(p, 0, nByte+nTemp);
+    }
+    p->pPhrase = (Fts3Phrase *)&p[1];
+    for(jj=0; jj<p->pPhrase->nToken; jj++){
+      p->pPhrase->aToken[jj].z = &zNew[nNew];
+      nNew += p->pPhrase->aToken[jj].n;
+    }
+    sqlite3_free(zTemp);
+    p->eType = FTSQUERY_PHRASE;
+    p->pPhrase->iColumn = pParse->iDefaultCol;
+    rc = SQLITE_OK;
+  }
+
+  *ppExpr = p;
+  return rc;
+no_mem:
+
+  if( pCursor ){
+    pModule->xClose(pCursor);
+  }
+  sqlite3_free(zTemp);
+  sqlite3_free(p);
+  *ppExpr = 0;
+  return SQLITE_NOMEM;
+}
+
+/*
+** Function getNextNode(), which is called by fts3ExprParse(), may itself
+** call fts3ExprParse(). So this forward declaration is required.
+*/
+static int fts3ExprParse(ParseContext *, const char *, int, Fts3Expr **, int *);
+
+/*
+** The output variable *ppExpr is populated with an allocated Fts3Expr
+** structure, or set to 0 if the end of the input buffer is reached.
+**
+** Returns an SQLite error code. SQLITE_OK if everything works, SQLITE_NOMEM
+** if a malloc failure occurs, or SQLITE_ERROR if a parse error is encountered.
+** If SQLITE_ERROR is returned, pContext is populated with an error message.
+*/
+static int getNextNode(
+  ParseContext *pParse,                   /* fts3 query parse context */
+  const char *z, int n,                   /* Input string */
+  Fts3Expr **ppExpr,                      /* OUT: expression */
+  int *pnConsumed                         /* OUT: Number of bytes consumed */
+){
+  static const struct Fts3Keyword {
+    char z[4];                            /* Keyword text */
+    unsigned char n;                      /* Length of the keyword */
+    unsigned char parenOnly;              /* Only valid in paren mode */
+    unsigned char eType;                  /* Keyword code */
+  } aKeyword[] = {
+    { "OR" ,  2, 0, FTSQUERY_OR   },
+    { "AND",  3, 1, FTSQUERY_AND  },
+    { "NOT",  3, 1, FTSQUERY_NOT  },
+    { "NEAR", 4, 0, FTSQUERY_NEAR }
+  };
+  int ii;
+  int iCol;
+  int iColLen;
+  int rc;
+  Fts3Expr *pRet = 0;
+
+  const char *zInput = z;
+  int nInput = n;
+
+  /* Skip over any whitespace before checking for a keyword, an open or
+  ** close bracket, or a quoted string.
+  */
+  while( nInput>0 && fts3isspace(*zInput) ){
+    nInput--;
+    zInput++;
+  }
+  if( nInput==0 ){
+    return SQLITE_DONE;
+  }
+
+  /* See if we are dealing with a keyword. */
+  for(ii=0; ii<(int)(sizeof(aKeyword)/sizeof(struct Fts3Keyword)); ii++){
+    const struct Fts3Keyword *pKey = &aKeyword[ii];
+
+    if( (pKey->parenOnly & ~sqlite3_fts3_enable_parentheses)!=0 ){
+      continue;
+    }
+
+    if( nInput>=pKey->n && 0==memcmp(zInput, pKey->z, pKey->n) ){
+      int nNear = SQLITE_FTS3_DEFAULT_NEAR_PARAM;
+      int nKey = pKey->n;
+      char cNext;
+
+      /* If this is a "NEAR" keyword, check for an explicit nearness. */
+      if( pKey->eType==FTSQUERY_NEAR ){
+        assert( nKey==4 );
+        if( zInput[4]=='/' && zInput[5]>='0' && zInput[5]<='9' ){
+          nNear = 0;
+          for(nKey=5; zInput[nKey]>='0' && zInput[nKey]<='9'; nKey++){
+            nNear = nNear * 10 + (zInput[nKey] - '0');
           }
         }
       }
-      *tokenType = TOKEN_STRING;
-      return i + (c!=0);
-    }
-    case '[': {
-      for(i=1, c=z[0]; c!=']' && (c=z[i])!=0; i++){}
-      *tokenType = TOKEN_ID;
-      return i;
-    }
-    default: {
-      if( !ftsIdChar(*z) ){
-        break;
-      }
-      for(i=1; ftsIdChar(z[i]); i++){}
-      *tokenType = TOKEN_ID;
-      return i;
-    }
-  }
-  *tokenType = TOKEN_PUNCT;
-  return 1;
-}
-
-/*
-** A token extracted from a string is an instance of the following
-** structure.
-*/
-typedef struct FtsToken {
-  const char *z;       /* Pointer to token text.  Not '\000' terminated */
-  short int n;         /* Length of the token text in bytes. */
-} FtsToken;
-
-/*
-** Given a input string (which is really one of the argv[] parameters
-** passed into xConnect or xCreate) split the string up into tokens.
-** Return an array of pointers to '\000' terminated strings, one string
-** for each non-whitespace token.
-**
-** The returned array is terminated by a single NULL pointer.
-**
-** Space to hold the returned array is obtained from a single
-** malloc and should be freed by passing the return value to free().
-** The individual strings within the token list are all a part of
-** the single memory allocation and will all be freed at once.
-*/
-static char **tokenizeString(const char *z, int *pnToken){
-  int nToken = 0;
-  FtsToken *aToken = sqlite3_malloc( strlen(z) * sizeof(aToken[0]) );
-  int n = 1;
-  int e, i;
-  int totalSize = 0;
-  char **azToken;
-  char *zCopy;
-  while( n>0 ){
-    n = ftsGetToken(z, &e);
-    if( e!=TOKEN_SPACE ){
-      aToken[nToken].z = z;
-      aToken[nToken].n = n;
-      nToken++;
-      totalSize += n+1;
-    }
-    z += n;
-  }
-  azToken = (char**)sqlite3_malloc( nToken*sizeof(char*) + totalSize );
-  zCopy = (char*)&azToken[nToken];
-  nToken--;
-  for(i=0; i<nToken; i++){
-    azToken[i] = zCopy;
-    n = aToken[i].n;
-    memcpy(zCopy, aToken[i].z, n);
-    zCopy[n] = 0;
-    zCopy += n+1;
-  }
-  azToken[nToken] = 0;
-  sqlite3_free(aToken);
-  *pnToken = nToken;
-  return azToken;
-}
-
-/*
-** Convert an SQL-style quoted string into a normal string by removing
-** the quote characters.  The conversion is done in-place.  If the
-** input does not begin with a quote character, then this routine
-** is a no-op.
-**
-** Examples:
-**
-**     "abc"   becomes   abc
-**     'xyz'   becomes   xyz
-**     [pqr]   becomes   pqr
-**     `mno`   becomes   mno
-*/
-static void dequoteString(char *z){
-  int quote;
-  int i, j;
-  if( z==0 ) return;
-  quote = z[0];
-  switch( quote ){
-    case '\'':  break;
-    case '"':   break;
-    case '`':   break;                /* For MySQL compatibility */
-    case '[':   quote = ']';  break;  /* For MS SqlServer compatibility */
-    default:    return;
-  }
-  for(i=1, j=0; z[i]; i++){
-    if( z[i]==quote ){
-      if( z[i+1]==quote ){
-        z[j++] = quote;
-        i++;
-      }else{
-        z[j++] = 0;
-        break;
-      }
-    }else{
-      z[j++] = z[i];
-    }
-  }
-}
-
-/*
-** The input azIn is a NULL-terminated list of tokens.  Remove the first
-** token and all punctuation tokens.  Remove the quotes from
-** around string literal tokens.
-**
-** Example:
-**
-**     input:      tokenize chinese ( 'simplifed' , 'mixed' )
-**     output:     chinese simplifed mixed
-**
-** Another example:
-**
-**     input:      delimiters ( '[' , ']' , '...' )
-**     output:     [ ] ...
-*/
-static void tokenListToIdList(char **azIn){
-  int i, j;
-  if( azIn ){
-    for(i=0, j=-1; azIn[i]; i++){
-      if( safe_isalnum(azIn[i][0]) || azIn[i][1] ){
-        dequoteString(azIn[i]);
-        if( j>=0 ){
-          azIn[j] = azIn[i];
-        }
-        j++;
-      }
-    }
-    azIn[j] = 0;
-  }
-}
-
-
-/*
-** Find the first alphanumeric token in the string zIn.  Null-terminate
-** this token.  Remove any quotation marks.  And return a pointer to
-** the result.
-*/
-static char *firstToken(char *zIn, char **pzTail){
-  int n, ttype;
-  while(1){
-    n = ftsGetToken(zIn, &ttype);
-    if( ttype==TOKEN_SPACE ){
-      zIn += n;
-    }else if( ttype==TOKEN_EOF ){
-      *pzTail = zIn;
-      return 0;
-    }else{
-      zIn[n] = 0;
-      *pzTail = &zIn[1];
-      dequoteString(zIn);
-      return zIn;
-    }
-  }
-  /*NOTREACHED*/
-}
-
-/* Return true if...
-**
-**   *  s begins with the string t, ignoring case
-**   *  s is longer than t
-**   *  The first character of s beyond t is not a alphanumeric
-**
-** Ignore leading space in *s.
-**
-** To put it another way, return true if the first token of
-** s[] is t[].
-*/
-static int startsWith(const char *s, const char *t){
-  while( safe_isspace(*s) ){ s++; }
-  while( *t ){
-    if( safe_tolower(*s++)!=safe_tolower(*t++) ) return 0;
-  }
-  return *s!='_' && !safe_isalnum(*s);
-}
-
-/*
-** An instance of this structure defines the "spec" of a
-** full text index.  This structure is populated by parseSpec
-** and use by fulltextConnect and fulltextCreate.
-*/
-typedef struct TableSpec {
-  const char *zDb;         /* Logical database name */
-  const char *zName;       /* Name of the full-text index */
-  int nColumn;             /* Number of columns to be indexed */
-  char **azColumn;         /* Original names of columns to be indexed */
-  char **azContentColumn;  /* Column names for %_content */
-  char **azTokenizer;      /* Name of tokenizer and its arguments */
-} TableSpec;
-
-/*
-** Reclaim all of the memory used by a TableSpec
-*/
-static void clearTableSpec(TableSpec *p) {
-  sqlite3_free(p->azColumn);
-  sqlite3_free(p->azContentColumn);
-  sqlite3_free(p->azTokenizer);
-}
-
-/* Parse a CREATE VIRTUAL TABLE statement, which looks like this:
- *
- * CREATE VIRTUAL TABLE email
- *        USING fts3(subject, body, tokenize mytokenizer(myarg))
- *
- * We return parsed information in a TableSpec structure.
- *
- */
-static int parseSpec(TableSpec *pSpec, int argc, const char *const*argv,
-                     char**pzErr){
-  int i, n;
-  char *z, *zDummy;
-  char **azArg;
-  const char *zTokenizer = 0;    /* argv[] entry describing the tokenizer */
-
-  assert( argc>=3 );
-  /* Current interface:
-  ** argv[0] - module name
-  ** argv[1] - database name
-  ** argv[2] - table name
-  ** argv[3..] - columns, optionally followed by tokenizer specification
-  **             and snippet delimiters specification.
-  */
-
-  /* Make a copy of the complete argv[][] array in a single allocation.
-  ** The argv[][] array is read-only and transient.  We can write to the
-  ** copy in order to modify things and the copy is persistent.
-  */
-  CLEAR(pSpec);
-  for(i=n=0; i<argc; i++){
-    n += strlen(argv[i]) + 1;
-  }
-  azArg = sqlite3_malloc( sizeof(char*)*argc + n );
-  if( azArg==0 ){
-    return SQLITE_NOMEM;
-  }
-  z = (char*)&azArg[argc];
-  for(i=0; i<argc; i++){
-    azArg[i] = z;
-    strcpy(z, argv[i]);
-    z += strlen(z)+1;
-  }
-
-  /* Identify the column names and the tokenizer and delimiter arguments
-  ** in the argv[][] array.
-  */
-  pSpec->zDb = azArg[1];
-  pSpec->zName = azArg[2];
-  pSpec->nColumn = 0;
-  pSpec->azColumn = azArg;
-  zTokenizer = "tokenize simple";
-  for(i=3; i<argc; ++i){
-    if( startsWith(azArg[i],"tokenize") ){
-      zTokenizer = azArg[i];
-    }else{
-      z = azArg[pSpec->nColumn] = firstToken(azArg[i], &zDummy);
-      pSpec->nColumn++;
-    }
-  }
-  if( pSpec->nColumn==0 ){
-    azArg[0] = "content";
-    pSpec->nColumn = 1;
-  }
-
-  /*
-  ** Construct the list of content column names.
-  **
-  ** Each content column name will be of the form cNNAAAA
-  ** where NN is the column number and AAAA is the sanitized
-  ** column name.  "sanitized" means that special characters are
-  ** converted to "_".  The cNN prefix guarantees that all column
-  ** names are unique.
-  **
-  ** The AAAA suffix is not strictly necessary.  It is included
-  ** for the convenience of people who might examine the generated
-  ** %_content table and wonder what the columns are used for.
-  */
-  pSpec->azContentColumn = sqlite3_malloc( pSpec->nColumn * sizeof(char *) );
-  if( pSpec->azContentColumn==0 ){
-    clearTableSpec(pSpec);
-    return SQLITE_NOMEM;
-  }
-  for(i=0; i<pSpec->nColumn; i++){
-    char *p;
-    pSpec->azContentColumn[i] = sqlite3_mprintf("c%d%s", i, azArg[i]);
-    for (p = pSpec->azContentColumn[i]; *p ; ++p) {
-      if( !safe_isalnum(*p) ) *p = '_';
-    }
-  }
-
-  /*
-  ** Parse the tokenizer specification string.
-  */
-  pSpec->azTokenizer = tokenizeString(zTokenizer, &n);
-  tokenListToIdList(pSpec->azTokenizer);
-
-  return SQLITE_OK;
-}
-
-/*
-** Generate a CREATE TABLE statement that describes the schema of
-** the virtual table.  Return a pointer to this schema string.
-**
-** Space is obtained from sqlite3_mprintf() and should be freed
-** using sqlite3_free().
-*/
-static char *fulltextSchema(
-  int nColumn,                  /* Number of columns */
-  const char *const* azColumn,  /* List of columns */
-  const char *zTableName        /* Name of the table */
-){
-  int i;
-  char *zSchema, *zNext;
-  const char *zSep = "(";
-  zSchema = sqlite3_mprintf("CREATE TABLE x");
-  for(i=0; i<nColumn; i++){
-    zNext = sqlite3_mprintf("%s%s%Q", zSchema, zSep, azColumn[i]);
-    sqlite3_free(zSchema);
-    zSchema = zNext;
-    zSep = ",";
-  }
-  zNext = sqlite3_mprintf("%s,%Q HIDDEN", zSchema, zTableName);
-  sqlite3_free(zSchema);
-  zSchema = zNext;
-  zNext = sqlite3_mprintf("%s,docid HIDDEN)", zSchema);
-  sqlite3_free(zSchema);
-  return zNext;
-}
-
-/*
-** Build a new sqlite3_vtab structure that will describe the
-** fulltext index defined by spec.
-*/
-static int constructVtab(
-  sqlite3 *db,              /* The SQLite database connection */
-  fts3Hash *pHash,          /* Hash table containing tokenizers */
-  TableSpec *spec,          /* Parsed spec information from parseSpec() */
-  sqlite3_vtab **ppVTab,    /* Write the resulting vtab structure here */
-  char **pzErr              /* Write any error message here */
-){
-  int rc;
-  int n;
-  fulltext_vtab *v = 0;
-  const sqlite3_tokenizer_module *m = NULL;
-  char *schema;
-
-  char const *zTok;         /* Name of tokenizer to use for this fts table */
-  int nTok;                 /* Length of zTok, including nul terminator */
-
-  v = (fulltext_vtab *) sqlite3_malloc(sizeof(fulltext_vtab));
-  if( v==0 ) return SQLITE_NOMEM;
-  CLEAR(v);
-  /* sqlite will initialize v->base */
-  v->db = db;
-  v->zDb = spec->zDb;       /* Freed when azColumn is freed */
-  v->zName = spec->zName;   /* Freed when azColumn is freed */
-  v->nColumn = spec->nColumn;
-  v->azContentColumn = spec->azContentColumn;
-  spec->azContentColumn = 0;
-  v->azColumn = spec->azColumn;
-  spec->azColumn = 0;
-
-  if( spec->azTokenizer==0 ){
-    return SQLITE_NOMEM;
-  }
-
-  zTok = spec->azTokenizer[0];
-  if( !zTok ){
-    zTok = "simple";
-  }
-  nTok = strlen(zTok)+1;
-
-  m = (sqlite3_tokenizer_module *)sqlite3Fts3HashFind(pHash, zTok, nTok);
-  if( !m ){
-    *pzErr = sqlite3_mprintf("unknown tokenizer: %s", spec->azTokenizer[0]);
-    rc = SQLITE_ERROR;
-    goto err;
-  }
-
-  for(n=0; spec->azTokenizer[n]; n++){}
-  if( n ){
-    rc = m->xCreate(n-1, (const char*const*)&spec->azTokenizer[1],
-                    &v->pTokenizer);
-  }else{
-    rc = m->xCreate(0, 0, &v->pTokenizer);
-  }
-  if( rc!=SQLITE_OK ) goto err;
-  v->pTokenizer->pModule = m;
-
-  /* TODO: verify the existence of backing tables foo_content, foo_term */
-
-  schema = fulltextSchema(v->nColumn, (const char*const*)v->azColumn,
-                          spec->zName);
-  rc = sqlite3_declare_vtab(db, schema);
-  sqlite3_free(schema);
-  if( rc!=SQLITE_OK ) goto err;
-
-  memset(v->pFulltextStatements, 0, sizeof(v->pFulltextStatements));
-
-  /* Indicate that the buffer is not live. */
-  v->nPendingData = -1;
-
-  *ppVTab = &v->base;
-  FTSTRACE(("FTS3 Connect %p\n", v));
-
-  return rc;
-
-err:
-  fulltext_vtab_destroy(v);
-  return rc;
-}
-
-static int fulltextConnect(
-  sqlite3 *db,
-  void *pAux,
-  int argc, const char *const*argv,
-  sqlite3_vtab **ppVTab,
-  char **pzErr
-){
-  TableSpec spec;
-  int rc = parseSpec(&spec, argc, argv, pzErr);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = constructVtab(db, (fts3Hash *)pAux, &spec, ppVTab, pzErr);
-  clearTableSpec(&spec);
-  return rc;
-}
-
-/* The %_content table holds the text of each document, with
-** the docid column exposed as the SQLite rowid for the table.
-*/
-/* TODO(shess) This comment needs elaboration to match the updated
-** code.  Work it into the top-of-file comment at that time.
-*/
-static int fulltextCreate(sqlite3 *db, void *pAux,
-                          int argc, const char * const *argv,
-                          sqlite3_vtab **ppVTab, char **pzErr){
-  int rc;
-  TableSpec spec;
-  StringBuffer schema;
-  FTSTRACE(("FTS3 Create\n"));
-
-  rc = parseSpec(&spec, argc, argv, pzErr);
-  if( rc!=SQLITE_OK ) return rc;
-
-  initStringBuffer(&schema);
-  append(&schema, "CREATE TABLE %_content(");
-  append(&schema, "  docid INTEGER PRIMARY KEY,");
-  appendList(&schema, spec.nColumn, spec.azContentColumn);
-  append(&schema, ")");
-  rc = sql_exec(db, spec.zDb, spec.zName, stringBufferData(&schema));
-  stringBufferDestroy(&schema);
-  if( rc!=SQLITE_OK ) goto out;
-
-  rc = sql_exec(db, spec.zDb, spec.zName,
-                "create table %_segments("
-                "  blockid INTEGER PRIMARY KEY,"
-                "  block blob"
-                ");"
-                );
-  if( rc!=SQLITE_OK ) goto out;
-
-  rc = sql_exec(db, spec.zDb, spec.zName,
-                "create table %_segdir("
-                "  level integer,"
-                "  idx integer,"
-                "  start_block integer,"
-                "  leaves_end_block integer,"
-                "  end_block integer,"
-                "  root blob,"
-                "  primary key(level, idx)"
-                ");");
-  if( rc!=SQLITE_OK ) goto out;
-
-  rc = constructVtab(db, (fts3Hash *)pAux, &spec, ppVTab, pzErr);
-
-out:
-  clearTableSpec(&spec);
-  return rc;
-}
-
-/* Decide how to handle an SQL query. */
-static int fulltextBestIndex(sqlite3_vtab *pVTab, sqlite3_index_info *pInfo){
-  fulltext_vtab *v = (fulltext_vtab *)pVTab;
-  int i;
-  FTSTRACE(("FTS3 BestIndex\n"));
-
-  for(i=0; i<pInfo->nConstraint; ++i){
-    const struct sqlite3_index_constraint *pConstraint;
-    pConstraint = &pInfo->aConstraint[i];
-    if( pConstraint->usable ) {
-      if( (pConstraint->iColumn==-1 || pConstraint->iColumn==v->nColumn+1) &&
-          pConstraint->op==SQLITE_INDEX_CONSTRAINT_EQ ){
-        pInfo->idxNum = QUERY_DOCID;      /* lookup by docid */
-        FTSTRACE(("FTS3 QUERY_DOCID\n"));
-      } else if( pConstraint->iColumn>=0 && pConstraint->iColumn<=v->nColumn &&
-                 pConstraint->op==SQLITE_INDEX_CONSTRAINT_MATCH ){
-        /* full-text search */
-        pInfo->idxNum = QUERY_FULLTEXT + pConstraint->iColumn;
-        FTSTRACE(("FTS3 QUERY_FULLTEXT %d\n", pConstraint->iColumn));
-      } else continue;
-
-      pInfo->aConstraintUsage[i].argvIndex = 1;
-      pInfo->aConstraintUsage[i].omit = 1;
-
-      /* An arbitrary value for now.
-       * TODO: Perhaps docid matches should be considered cheaper than
-       * full-text searches. */
-      pInfo->estimatedCost = 1.0;
-
-      return SQLITE_OK;
-    }
-  }
-  pInfo->idxNum = QUERY_GENERIC;
-  return SQLITE_OK;
-}
-
-static int fulltextDisconnect(sqlite3_vtab *pVTab){
-  FTSTRACE(("FTS3 Disconnect %p\n", pVTab));
-  fulltext_vtab_destroy((fulltext_vtab *)pVTab);
-  return SQLITE_OK;
-}
-
-static int fulltextDestroy(sqlite3_vtab *pVTab){
-  fulltext_vtab *v = (fulltext_vtab *)pVTab;
-  int rc;
-
-  FTSTRACE(("FTS3 Destroy %p\n", pVTab));
-  rc = sql_exec(v->db, v->zDb, v->zName,
-                "drop table if exists %_content;"
-                "drop table if exists %_segments;"
-                "drop table if exists %_segdir;"
-                );
-  if( rc!=SQLITE_OK ) return rc;
-
-  fulltext_vtab_destroy((fulltext_vtab *)pVTab);
-  return SQLITE_OK;
-}
-
-static int fulltextOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
-  fulltext_cursor *c;
-
-  c = (fulltext_cursor *) sqlite3_malloc(sizeof(fulltext_cursor));
-  if( c ){
-    memset(c, 0, sizeof(fulltext_cursor));
-    /* sqlite will initialize c->base */
-    *ppCursor = &c->base;
-    FTSTRACE(("FTS3 Open %p: %p\n", pVTab, c));
-    return SQLITE_OK;
-  }else{
-    return SQLITE_NOMEM;
-  }
-}
-
-/* Free all of the dynamically allocated memory held by the
-** Snippet
-*/
-static void snippetClear(Snippet *p){
-  sqlite3_free(p->aMatch);
-  sqlite3_free(p->zOffset);
-  sqlite3_free(p->zSnippet);
-  CLEAR(p);
-}
-
-/*
-** Append a single entry to the p->aMatch[] log.
-*/
-static void snippetAppendMatch(
-  Snippet *p,               /* Append the entry to this snippet */
-  int iCol, int iTerm,      /* The column and query term */
-  int iToken,               /* Matching token in document */
-  int iStart, int nByte     /* Offset and size of the match */
-){
-  int i;
-  struct snippetMatch *pMatch;
-  if( p->nMatch+1>=p->nAlloc ){
-    p->nAlloc = p->nAlloc*2 + 10;
-    p->aMatch = sqlite3_realloc(p->aMatch, p->nAlloc*sizeof(p->aMatch[0]) );
-    if( p->aMatch==0 ){
-      p->nMatch = 0;
-      p->nAlloc = 0;
-      return;
-    }
-  }
-  i = p->nMatch++;
-  pMatch = &p->aMatch[i];
-  pMatch->iCol = iCol;
-  pMatch->iTerm = iTerm;
-  pMatch->iToken = iToken;
-  pMatch->iStart = iStart;
-  pMatch->nByte = nByte;
-}
-
-/*
-** Sizing information for the circular buffer used in snippetOffsetsOfColumn()
-*/
-#define FTS3_ROTOR_SZ   (32)
-#define FTS3_ROTOR_MASK (FTS3_ROTOR_SZ-1)
-
-/*
-** Function to iterate through the tokens of a compiled expression.
-**
-** Except, skip all tokens on the right-hand side of a NOT operator.
-** This function is used to find tokens as part of snippet and offset
-** generation and we do nt want snippets and offsets to report matches
-** for tokens on the RHS of a NOT.
-*/
-static int fts3NextExprToken(Fts3Expr **ppExpr, int *piToken){
-  Fts3Expr *p = *ppExpr;
-  int iToken = *piToken;
-  if( iToken<0 ){
-    /* In this case the expression p is the root of an expression tree.
-    ** Move to the first token in the expression tree.
-    */
-    while( p->pLeft ){
-      p = p->pLeft;
-    }
-    iToken = 0;
-  }else{
-    assert(p && p->eType==FTSQUERY_PHRASE );
-    if( iToken<(p->pPhrase->nToken-1) ){
-      iToken++;
-    }else{
-      iToken = 0;
-      while( p->pParent && p->pParent->pLeft!=p ){
-        assert( p->pParent->pRight==p );
-        p = p->pParent;
-      }
-      p = p->pParent;
-      if( p ){
-        assert( p->pRight!=0 );
-        p = p->pRight;
-        while( p->pLeft ){
-          p = p->pLeft;
-        }
-      }
-    }
-  }
-
-  *ppExpr = p;
-  *piToken = iToken;
-  return p?1:0;
-}
-
-/*
-** Return TRUE if the expression node pExpr is located beneath the
-** RHS of a NOT operator.
-*/
-static int fts3ExprBeneathNot(Fts3Expr *p){
-  Fts3Expr *pParent;
-  while( p ){
-    pParent = p->pParent;
-    if( pParent && pParent->eType==FTSQUERY_NOT && pParent->pRight==p ){
-      return 1;
-    }
-    p = pParent;
-  }
-  return 0;
-}
-
-/*
-** Add entries to pSnippet->aMatch[] for every match that occurs against
-** document zDoc[0..nDoc-1] which is stored in column iColumn.
-*/
-static void snippetOffsetsOfColumn(
-  fulltext_cursor *pCur,         /* The fulltest search cursor */
-  Snippet *pSnippet,             /* The Snippet object to be filled in */
-  int iColumn,                   /* Index of fulltext table column */
-  const char *zDoc,              /* Text of the fulltext table column */
-  int nDoc                       /* Length of zDoc in bytes */
-){
-  const sqlite3_tokenizer_module *pTModule;  /* The tokenizer module */
-  sqlite3_tokenizer *pTokenizer;             /* The specific tokenizer */
-  sqlite3_tokenizer_cursor *pTCursor;        /* Tokenizer cursor */
-  fulltext_vtab *pVtab;                /* The full text index */
-  int nColumn;                         /* Number of columns in the index */
-  int i, j;                            /* Loop counters */
-  int rc;                              /* Return code */
-  unsigned int match, prevMatch;       /* Phrase search bitmasks */
-  const char *zToken;                  /* Next token from the tokenizer */
-  int nToken;                          /* Size of zToken */
-  int iBegin, iEnd, iPos;              /* Offsets of beginning and end */
-
-  /* The following variables keep a circular buffer of the last
-  ** few tokens */
-  unsigned int iRotor = 0;             /* Index of current token */
-  int iRotorBegin[FTS3_ROTOR_SZ];      /* Beginning offset of token */
-  int iRotorLen[FTS3_ROTOR_SZ];        /* Length of token */
-
-  pVtab = cursor_vtab(pCur);
-  nColumn = pVtab->nColumn;
-  pTokenizer = pVtab->pTokenizer;
-  pTModule = pTokenizer->pModule;
-  rc = pTModule->xOpen(pTokenizer, zDoc, nDoc, &pTCursor);
-  if( rc ) return;
-  pTCursor->pTokenizer = pTokenizer;
-
-  prevMatch = 0;
-  while( !pTModule->xNext(pTCursor, &zToken, &nToken, &iBegin, &iEnd, &iPos) ){
-    Fts3Expr *pIter = pCur->pExpr;
-    int iIter = -1;
-    iRotorBegin[iRotor&FTS3_ROTOR_MASK] = iBegin;
-    iRotorLen[iRotor&FTS3_ROTOR_MASK] = iEnd-iBegin;
-    match = 0;
-    for(i=0; i<(FTS3_ROTOR_SZ-1) && fts3NextExprToken(&pIter, &iIter); i++){
-      int nPhrase;                    /* Number of tokens in current phrase */
-      struct PhraseToken *pToken;     /* Current token */
-      int iCol;                       /* Column index */
-
-      if( fts3ExprBeneathNot(pIter) ) continue;
-      nPhrase = pIter->pPhrase->nToken;
-      pToken = &pIter->pPhrase->aToken[iIter];
-      iCol = pIter->pPhrase->iColumn;
-      if( iCol>=0 && iCol<nColumn && iCol!=iColumn ) continue;
-      if( pToken->n>nToken ) continue;
-      if( !pToken->isPrefix && pToken->n<nToken ) continue;
-      assert( pToken->n<=nToken );
-      if( memcmp(pToken->z, zToken, pToken->n) ) continue;
-      if( iIter>0 && (prevMatch & (1<<i))==0 ) continue;
-      match |= 1<<i;
-      if( i==(FTS3_ROTOR_SZ-2) || nPhrase==iIter+1 ){
-        for(j=nPhrase-1; j>=0; j--){
-          int k = (iRotor-j) & FTS3_ROTOR_MASK;
-          snippetAppendMatch(pSnippet, iColumn, i-j, iPos-j,
-                iRotorBegin[k], iRotorLen[k]);
-        }
-      }
-    }
-    prevMatch = match<<1;
-    iRotor++;
-  }
-  pTModule->xClose(pTCursor);
-}
-
-/*
-** Remove entries from the pSnippet structure to account for the NEAR
-** operator. When this is called, pSnippet contains the list of token
-** offsets produced by treating all NEAR operators as AND operators.
-** This function removes any entries that should not be present after
-** accounting for the NEAR restriction. For example, if the queried
-** document is:
-**
-**     "A B C D E A"
-**
-** and the query is:
-**
-**     A NEAR/0 E
-**
-** then when this function is called the Snippet contains token offsets
-** 0, 4 and 5. This function removes the "0" entry (because the first A
-** is not near enough to an E).
-**
-** When this function is called, the value pointed to by parameter piLeft is
-** the integer id of the left-most token in the expression tree headed by
-** pExpr. This function increments *piLeft by the total number of tokens
-** in the expression tree headed by pExpr.
-**
-** Return 1 if any trimming occurs.  Return 0 if no trimming is required.
-*/
-static int trimSnippetOffsets(
-  Fts3Expr *pExpr,      /* The search expression */
-  Snippet *pSnippet,    /* The set of snippet offsets to be trimmed */
-  int *piLeft           /* Index of left-most token in pExpr */
-){
-  if( pExpr ){
-    if( trimSnippetOffsets(pExpr->pLeft, pSnippet, piLeft) ){
-      return 1;
-    }
-
-    switch( pExpr->eType ){
-      case FTSQUERY_PHRASE:
-        *piLeft += pExpr->pPhrase->nToken;
-        break;
-      case FTSQUERY_NEAR: {
-        /* The right-hand-side of a NEAR operator is always a phrase. The
-        ** left-hand-side is either a phrase or an expression tree that is
-        ** itself headed by a NEAR operator. The following initializations
-        ** set local variable iLeft to the token number of the left-most
-        ** token in the right-hand phrase, and iRight to the right most
-        ** token in the same phrase. For example, if we had:
-        **
-        **     <col> MATCH '"abc def" NEAR/2 "ghi jkl"'
-        **
-        ** then iLeft will be set to 2 (token number of ghi) and nToken will
-        ** be set to 4.
-        */
-        Fts3Expr *pLeft = pExpr->pLeft;
-        Fts3Expr *pRight = pExpr->pRight;
-        int iLeft = *piLeft;
-        int nNear = pExpr->nNear;
-        int nToken = pRight->pPhrase->nToken;
-        int jj, ii;
-        if( pLeft->eType==FTSQUERY_NEAR ){
-          pLeft = pLeft->pRight;
-        }
-        assert( pRight->eType==FTSQUERY_PHRASE );
-        assert( pLeft->eType==FTSQUERY_PHRASE );
-        nToken += pLeft->pPhrase->nToken;
-
-        for(ii=0; ii<pSnippet->nMatch; ii++){
-          struct snippetMatch *p = &pSnippet->aMatch[ii];
-          if( p->iTerm==iLeft ){
-            int isOk = 0;
-            /* Snippet ii is an occurence of query term iLeft in the document.
-            ** It occurs at position (p->iToken) of the document. We now
-            ** search for an instance of token (iLeft-1) somewhere in the
-            ** range (p->iToken - nNear)...(p->iToken + nNear + nToken) within
-            ** the set of snippetMatch structures. If one is found, proceed.
-            ** If one cannot be found, then remove snippets ii..(ii+N-1)
-            ** from the matching snippets, where N is the number of tokens
-            ** in phrase pRight->pPhrase.
-            */
-            for(jj=0; isOk==0 && jj<pSnippet->nMatch; jj++){
-              struct snippetMatch *p2 = &pSnippet->aMatch[jj];
-              if( p2->iTerm==(iLeft-1) ){
-                if( p2->iToken>=(p->iToken-nNear-1)
-                 && p2->iToken<(p->iToken+nNear+nToken)
-                ){
-                  isOk = 1;
-                }
-              }
-            }
-            if( !isOk ){
-              int kk;
-              for(kk=0; kk<pRight->pPhrase->nToken; kk++){
-                pSnippet->aMatch[kk+ii].iTerm = -2;
-              }
-              return 1;
-            }
-          }
-          if( p->iTerm==(iLeft-1) ){
-            int isOk = 0;
-            for(jj=0; isOk==0 && jj<pSnippet->nMatch; jj++){
-              struct snippetMatch *p2 = &pSnippet->aMatch[jj];
-              if( p2->iTerm==iLeft ){
-                if( p2->iToken<=(p->iToken+nNear+1)
-                 && p2->iToken>(p->iToken-nNear-nToken)
-                ){
-                  isOk = 1;
-                }
-              }
-            }
-            if( !isOk ){
-              int kk;
-              for(kk=0; kk<pLeft->pPhrase->nToken; kk++){
-                pSnippet->aMatch[ii-kk].iTerm = -2;
-              }
-              return 1;
-            }
-          }
-        }
-        break;
-      }
-    }
-
-    if( trimSnippetOffsets(pExpr->pRight, pSnippet, piLeft) ){
-      return 1;
-    }
-  }
-  return 0;
-}
-
-/*
-** Compute all offsets for the current row of the query.
-** If the offsets have already been computed, this routine is a no-op.
-*/
-static void snippetAllOffsets(fulltext_cursor *p){
-  int nColumn;
-  int iColumn, i;
-  int iFirst, iLast;
-  int iTerm = 0;
-  fulltext_vtab *pFts = cursor_vtab(p);
-
-  if( p->snippet.nMatch || p->pExpr==0 ){
-    return;
-  }
-  nColumn = pFts->nColumn;
-  iColumn = (p->iCursorType - QUERY_FULLTEXT);
-  if( iColumn<0 || iColumn>=nColumn ){
-    /* Look for matches over all columns of the full-text index */
-    iFirst = 0;
-    iLast = nColumn-1;
-  }else{
-    /* Look for matches in the iColumn-th column of the index only */
-    iFirst = iColumn;
-    iLast = iColumn;
-  }
-  for(i=iFirst; i<=iLast; i++){
-    const char *zDoc;
-    int nDoc;
-    zDoc = (const char*)sqlite3_column_text(p->pStmt, i+1);
-    nDoc = sqlite3_column_bytes(p->pStmt, i+1);
-    snippetOffsetsOfColumn(p, &p->snippet, i, zDoc, nDoc);
-  }
-
-  while( trimSnippetOffsets(p->pExpr, &p->snippet, &iTerm) ){
-    iTerm = 0;
-  }
-}
-
-/*
-** Convert the information in the aMatch[] array of the snippet
-** into the string zOffset[0..nOffset-1]. This string is used as
-** the return of the SQL offsets() function.
-*/
-static void snippetOffsetText(Snippet *p){
-  int i;
-  int cnt = 0;
-  StringBuffer sb;
-  char zBuf[200];
-  if( p->zOffset ) return;
-  initStringBuffer(&sb);
-  for(i=0; i<p->nMatch; i++){
-    struct snippetMatch *pMatch = &p->aMatch[i];
-    if( pMatch->iTerm>=0 ){
-      /* If snippetMatch.iTerm is less than 0, then the match was
-      ** discarded as part of processing the NEAR operator (see the
-      ** trimSnippetOffsetsForNear() function for details). Ignore
-      ** it in this case
+
+      /* At this point this is probably a keyword. But for that to be true,
+      ** the next byte must contain either whitespace, an open or close
+      ** parenthesis, a quote character, or EOF.
       */
-      zBuf[0] = ' ';
-      sqlite3_snprintf(sizeof(zBuf)-1, &zBuf[cnt>0], "%d %d %d %d",
-          pMatch->iCol, pMatch->iTerm, pMatch->iStart, pMatch->nByte);
-      append(&sb, zBuf);
-      cnt++;
-    }
-  }
-  p->zOffset = stringBufferData(&sb);
-  p->nOffset = stringBufferLength(&sb);
-}
-
-/*
-** zDoc[0..nDoc-1] is phrase of text.  aMatch[0..nMatch-1] are a set
-** of matching words some of which might be in zDoc.  zDoc is column
-** number iCol.
-**
-** iBreak is suggested spot in zDoc where we could begin or end an
-** excerpt.  Return a value similar to iBreak but possibly adjusted
-** to be a little left or right so that the break point is better.
-*/
-static int wordBoundary(
-  int iBreak,                   /* The suggested break point */
-  const char *zDoc,             /* Document text */
-  int nDoc,                     /* Number of bytes in zDoc[] */
-  struct snippetMatch *aMatch,  /* Matching words */
-  int nMatch,                   /* Number of entries in aMatch[] */
-  int iCol                      /* The column number for zDoc[] */
-){
-  int i;
-  if( iBreak<=10 ){
-    return 0;
-  }
-  if( iBreak>=nDoc-10 ){
-    return nDoc;
-  }
-  for(i=0; i<nMatch && aMatch[i].iCol<iCol; i++){}
-  while( i<nMatch && aMatch[i].iStart+aMatch[i].nByte<iBreak ){ i++; }
-  if( i<nMatch ){
-    if( aMatch[i].iStart<iBreak+10 ){
-      return aMatch[i].iStart;
-    }
-    if( i>0 && aMatch[i-1].iStart+aMatch[i-1].nByte>=iBreak ){
-      return aMatch[i-1].iStart;
-    }
-  }
-  for(i=1; i<=10; i++){
-    if( safe_isspace(zDoc[iBreak-i]) ){
-      return iBreak - i + 1;
-    }
-    if( safe_isspace(zDoc[iBreak+i]) ){
-      return iBreak + i + 1;
-    }
-  }
-  return iBreak;
-}
-
-
-
-/*
-** Allowed values for Snippet.aMatch[].snStatus
-*/
-#define SNIPPET_IGNORE  0   /* It is ok to omit this match from the snippet */
-#define SNIPPET_DESIRED 1   /* We want to include this match in the snippet */
-
-/*
-** Generate the text of a snippet.
-*/
-static void snippetText(
-  fulltext_cursor *pCursor,   /* The cursor we need the snippet for */
-  const char *zStartMark,     /* Markup to appear before each match */
-  const char *zEndMark,       /* Markup to appear after each match */
-  const char *zEllipsis       /* Ellipsis mark */
-){
-  int i, j;
-  struct snippetMatch *aMatch;
-  int nMatch;
-  int nDesired;
-  StringBuffer sb;
-  int tailCol;
-  int tailOffset;
-  int iCol;
-  int nDoc;
-  const char *zDoc;
-  int iStart, iEnd;
-  int tailEllipsis = 0;
-  int iMatch;
-
-
-  sqlite3_free(pCursor->snippet.zSnippet);
-  pCursor->snippet.zSnippet = 0;
-  aMatch = pCursor->snippet.aMatch;
-  nMatch = pCursor->snippet.nMatch;
-  initStringBuffer(&sb);
-
-  for(i=0; i<nMatch; i++){
-    aMatch[i].snStatus = SNIPPET_IGNORE;
-  }
-  nDesired = 0;
-  for(i=0; i<FTS3_ROTOR_SZ; i++){
-    for(j=0; j<nMatch; j++){
-      if( aMatch[j].iTerm==i ){
-        aMatch[j].snStatus = SNIPPET_DESIRED;
-        nDesired++;
-        break;
-      }
-    }
-  }
-
-  iMatch = 0;
-  tailCol = -1;
-  tailOffset = 0;
-  for(i=0; i<nMatch && nDesired>0; i++){
-    if( aMatch[i].snStatus!=SNIPPET_DESIRED ) continue;
-    nDesired--;
-    iCol = aMatch[i].iCol;
-    zDoc = (const char*)sqlite3_column_text(pCursor->pStmt, iCol+1);
-    nDoc = sqlite3_column_bytes(pCursor->pStmt, iCol+1);
-    iStart = aMatch[i].iStart - 40;
-    iStart = wordBoundary(iStart, zDoc, nDoc, aMatch, nMatch, iCol);
-    if( iStart<=10 ){
-      iStart = 0;
-    }
-    if( iCol==tailCol && iStart<=tailOffset+20 ){
-      iStart = tailOffset;
-    }
-    if( (iCol!=tailCol && tailCol>=0) || iStart!=tailOffset ){
-      trimWhiteSpace(&sb);
-      appendWhiteSpace(&sb);
-      append(&sb, zEllipsis);
-      appendWhiteSpace(&sb);
-    }
-    iEnd = aMatch[i].iStart + aMatch[i].nByte + 40;
-    iEnd = wordBoundary(iEnd, zDoc, nDoc, aMatch, nMatch, iCol);
-    if( iEnd>=nDoc-10 ){
-      iEnd = nDoc;
-      tailEllipsis = 0;
-    }else{
-      tailEllipsis = 1;
-    }
-    while( iMatch<nMatch && aMatch[iMatch].iCol<iCol ){ iMatch++; }
-    while( iStart<iEnd ){
-      while( iMatch<nMatch && aMatch[iMatch].iStart<iStart
-             && aMatch[iMatch].iCol<=iCol ){
-        iMatch++;
-      }
-      if( iMatch<nMatch && aMatch[iMatch].iStart<iEnd
-             && aMatch[iMatch].iCol==iCol ){
-        nappend(&sb, &zDoc[iStart], aMatch[iMatch].iStart - iStart);
-        iStart = aMatch[iMatch].iStart;
-        append(&sb, zStartMark);
-        nappend(&sb, &zDoc[iStart], aMatch[iMatch].nByte);
-        append(&sb, zEndMark);
-        iStart += aMatch[iMatch].nByte;
-        for(j=iMatch+1; j<nMatch; j++){
-          if( aMatch[j].iTerm==aMatch[iMatch].iTerm
-              && aMatch[j].snStatus==SNIPPET_DESIRED ){
-            nDesired--;
-            aMatch[j].snStatus = SNIPPET_IGNORE;
-          }
-        }
-      }else{
-        nappend(&sb, &zDoc[iStart], iEnd - iStart);
-        iStart = iEnd;
-      }
-    }
-    tailCol = iCol;
-    tailOffset = iEnd;
-  }
-  trimWhiteSpace(&sb);
-  if( tailEllipsis ){
-    appendWhiteSpace(&sb);
-    append(&sb, zEllipsis);
-  }
-  pCursor->snippet.zSnippet = stringBufferData(&sb);
-  pCursor->snippet.nSnippet = stringBufferLength(&sb);
-}
-
-
-/*
-** Close the cursor.  For additional information see the documentation
-** on the xClose method of the virtual table interface.
-*/
-static int fulltextClose(sqlite3_vtab_cursor *pCursor){
-  fulltext_cursor *c = (fulltext_cursor *) pCursor;
-  FTSTRACE(("FTS3 Close %p\n", c));
-  sqlite3_finalize(c->pStmt);
-  sqlite3Fts3ExprFree(c->pExpr);
-  snippetClear(&c->snippet);
-  if( c->result.nData!=0 ){
-    dlrDestroy(&c->reader);
-  }
-  dataBufferDestroy(&c->result);
-  sqlite3_free(c);
-  return SQLITE_OK;
-}
-
-static int fulltextNext(sqlite3_vtab_cursor *pCursor){
-  fulltext_cursor *c = (fulltext_cursor *) pCursor;
-  int rc;
-
-  FTSTRACE(("FTS3 Next %p\n", pCursor));
-  snippetClear(&c->snippet);
-  if( c->iCursorType < QUERY_FULLTEXT ){
-    /* TODO(shess) Handle SQLITE_SCHEMA AND SQLITE_BUSY. */
-    rc = sqlite3_step(c->pStmt);
-    switch( rc ){
-      case SQLITE_ROW:
-        c->eof = 0;
-        return SQLITE_OK;
-      case SQLITE_DONE:
-        c->eof = 1;
-        return SQLITE_OK;
-      default:
-        c->eof = 1;
-        return rc;
-    }
-  } else {  /* full-text query */
-    rc = sqlite3_reset(c->pStmt);
-    if( rc!=SQLITE_OK ) return rc;
-
-    if( c->result.nData==0 || dlrAtEnd(&c->reader) ){
-      c->eof = 1;
-      return SQLITE_OK;
-    }
-    rc = sqlite3_bind_int64(c->pStmt, 1, dlrDocid(&c->reader));
-    dlrStep(&c->reader);
-    if( rc!=SQLITE_OK ) return rc;
-    /* TODO(shess) Handle SQLITE_SCHEMA AND SQLITE_BUSY. */
-    rc = sqlite3_step(c->pStmt);
-    if( rc==SQLITE_ROW ){   /* the case we expect */
-      c->eof = 0;
-      return SQLITE_OK;
-    }
-    /* an error occurred; abort */
-    return rc==SQLITE_DONE ? SQLITE_ERROR : rc;
-  }
-}
-
-
-/* TODO(shess) If we pushed LeafReader to the top of the file, or to
-** another file, term_select() could be pushed above
-** docListOfTerm().
-*/
-static int termSelect(fulltext_vtab *v, int iColumn,
-                      const char *pTerm, int nTerm, int isPrefix,
-                      DocListType iType, DataBuffer *out);
-
-/*
-** Return a DocList corresponding to the phrase *pPhrase.
-**
-** The resulting DL_DOCIDS doclist is stored in pResult, which is
-** overwritten.
-*/
-static int docListOfPhrase(
-  fulltext_vtab *pTab,   /* The full text index */
-  Fts3Phrase *pPhrase,   /* Phrase to return a doclist corresponding to */
-  DocListType eListType, /* Either DL_DOCIDS or DL_POSITIONS */
-  DataBuffer *pResult    /* Write the result here */
-){
-  int ii;
-  int rc = SQLITE_OK;
-  int iCol = pPhrase->iColumn;
-  DocListType eType = eListType;
-  assert( eType==DL_POSITIONS || eType==DL_DOCIDS );
-  if( pPhrase->nToken>1 ){
-    eType = DL_POSITIONS;
-  }
-
-  /* This code should never be called with buffered updates. */
-  assert( pTab->nPendingData<0 );
-
-  for(ii=0; rc==SQLITE_OK && ii<pPhrase->nToken; ii++){
-    DataBuffer tmp;
-    struct PhraseToken *p = &pPhrase->aToken[ii];
-    rc = termSelect(pTab, iCol, p->z, p->n, p->isPrefix, eType, &tmp);
-    if( rc==SQLITE_OK ){
-      if( ii==0 ){
-        *pResult = tmp;
-      }else{
-        DataBuffer res = *pResult;
-        dataBufferInit(pResult, 0);
-        if( ii==(pPhrase->nToken-1) ){
-          eType = eListType;
-        }
-        docListPhraseMerge(
-          res.pData, res.nData, tmp.pData, tmp.nData, 0, 0, eType, pResult
-        );
-        dataBufferDestroy(&res);
-        dataBufferDestroy(&tmp);
-      }
-    }
-  }
-
-  return rc;
-}
-
-/*
-** Evaluate the full-text expression pExpr against fts3 table pTab. Write
-** the results into pRes.
-*/
-static int evalFts3Expr(
-  fulltext_vtab *pTab,           /* Fts3 Virtual table object */
-  Fts3Expr *pExpr,               /* Parsed fts3 expression */
-  DataBuffer *pRes               /* OUT: Write results of the expression here */
-){
-  int rc = SQLITE_OK;
-
-  /* Initialize the output buffer. If this is an empty query (pExpr==0),
-  ** this is all that needs to be done. Empty queries produce empty
-  ** result sets.
-  */
-  dataBufferInit(pRes, 0);
-
-  if( pExpr ){
-    if( pExpr->eType==FTSQUERY_PHRASE ){
-      DocListType eType = DL_DOCIDS;
-      if( pExpr->pParent && pExpr->pParent->eType==FTSQUERY_NEAR ){
-        eType = DL_POSITIONS;
-      }
-      rc = docListOfPhrase(pTab, pExpr->pPhrase, eType, pRes);
-    }else{
-      DataBuffer lhs;
-      DataBuffer rhs;
-
-      dataBufferInit(&rhs, 0);
-      if( SQLITE_OK==(rc = evalFts3Expr(pTab, pExpr->pLeft, &lhs))
-       && SQLITE_OK==(rc = evalFts3Expr(pTab, pExpr->pRight, &rhs))
+      cNext = zInput[nKey];
+      if( fts3isspace(cNext)
+       || cNext=='"' || cNext=='(' || cNext==')' || cNext==0
       ){
-        switch( pExpr->eType ){
-          case FTSQUERY_NEAR: {
-            int nToken;
-            Fts3Expr *pLeft;
-            DocListType eType = DL_DOCIDS;
-            if( pExpr->pParent && pExpr->pParent->eType==FTSQUERY_NEAR ){
-              eType = DL_POSITIONS;
-            }
-            pLeft = pExpr->pLeft;
-            while( pLeft->eType==FTSQUERY_NEAR ){
-              pLeft=pLeft->pRight;
-            }
-            assert( pExpr->pRight->eType==FTSQUERY_PHRASE );
-            assert( pLeft->eType==FTSQUERY_PHRASE );
-            nToken = pLeft->pPhrase->nToken + pExpr->pRight->pPhrase->nToken;
-            docListPhraseMerge(lhs.pData, lhs.nData, rhs.pData, rhs.nData,
-                pExpr->nNear+1, nToken, eType, pRes
-            );
-            break;
-          }
-          case FTSQUERY_NOT: {
-            docListExceptMerge(lhs.pData, lhs.nData, rhs.pData, rhs.nData,pRes);
-            break;
-          }
-          case FTSQUERY_AND: {
-            docListAndMerge(lhs.pData, lhs.nData, rhs.pData, rhs.nData, pRes);
-            break;
-          }
-          case FTSQUERY_OR: {
-            docListOrMerge(lhs.pData, lhs.nData, rhs.pData, rhs.nData, pRes);
-            break;
-          }
-        }
-      }
-      dataBufferDestroy(&lhs);
-      dataBufferDestroy(&rhs);
-    }
-  }
-
-  return rc;
-}
-
-/* TODO(shess) Refactor the code to remove this forward decl. */
-static int flushPendingTerms(fulltext_vtab *v);
-
-/* Perform a full-text query using the search expression in
-** zInput[0..nInput-1].  Return a list of matching documents
-** in pResult.
-**
-** Queries must match column iColumn.  Or if iColumn>=nColumn
-** they are allowed to match against any column.
-*/
-static int fulltextQuery(
-  fulltext_vtab *v,      /* The full text index */
-  int iColumn,           /* Match against this column by default */
-  const char *zInput,    /* The query string */
-  int nInput,            /* Number of bytes in zInput[] */
-  DataBuffer *pResult,   /* Write the result doclist here */
-  Fts3Expr **ppExpr        /* Put parsed query string here */
-){
-  int rc;
-
-  /* TODO(shess) Instead of flushing pendingTerms, we could query for
-  ** the relevant term and merge the doclist into what we receive from
-  ** the database.  Wait and see if this is a common issue, first.
-  **
-  ** A good reason not to flush is to not generate update-related
-  ** error codes from here.
-  */
-
-  /* Flush any buffered updates before executing the query. */
-  rc = flushPendingTerms(v);
-  if( rc!=SQLITE_OK ){
-    return rc;
-  }
-
-  /* Parse the query passed to the MATCH operator. */
-  rc = sqlite3Fts3ExprParse(v->pTokenizer,
-      v->azColumn, v->nColumn, iColumn, zInput, nInput, ppExpr
-  );
-  if( rc!=SQLITE_OK ){
-    assert( 0==(*ppExpr) );
-    return rc;
-  }
-
-  return evalFts3Expr(v, *ppExpr, pResult);
-}
-
-/*
-** This is the xFilter interface for the virtual table.  See
-** the virtual table xFilter method documentation for additional
-** information.
-**
-** If idxNum==QUERY_GENERIC then do a full table scan against
-** the %_content table.
-**
-** If idxNum==QUERY_DOCID then do a docid lookup for a single entry
-** in the %_content table.
-**
-** If idxNum>=QUERY_FULLTEXT then use the full text index.  The
-** column on the left-hand side of the MATCH operator is column
-** number idxNum-QUERY_FULLTEXT, 0 indexed.  argv[0] is the right-hand
-** side of the MATCH operator.
-*/
-/* TODO(shess) Upgrade the cursor initialization and destruction to
-** account for fulltextFilter() being called multiple times on the
-** same cursor.  The current solution is very fragile.  Apply fix to
-** fts3 as appropriate.
-*/
-static int fulltextFilter(
-  sqlite3_vtab_cursor *pCursor,     /* The cursor used for this query */
-  int idxNum, const char *idxStr,   /* Which indexing scheme to use */
-  int argc, sqlite3_value **argv    /* Arguments for the indexing scheme */
-){
-  fulltext_cursor *c = (fulltext_cursor *) pCursor;
-  fulltext_vtab *v = cursor_vtab(c);
-  int rc;
-
-  FTSTRACE(("FTS3 Filter %p\n",pCursor));
-
-  /* If the cursor has a statement that was not prepared according to
-  ** idxNum, clear it.  I believe all calls to fulltextFilter with a
-  ** given cursor will have the same idxNum , but in this case it's
-  ** easy to be safe.
-  */
-  if( c->pStmt && c->iCursorType!=idxNum ){
-    sqlite3_finalize(c->pStmt);
-    c->pStmt = NULL;
-  }
-
-  /* Get a fresh statement appropriate to idxNum. */
-  /* TODO(shess): Add a prepared-statement cache in the vt structure.
-  ** The cache must handle multiple open cursors.  Easier to cache the
-  ** statement variants at the vt to reduce malloc/realloc/free here.
-  ** Or we could have a StringBuffer variant which allowed stack
-  ** construction for small values.
-  */
-  if( !c->pStmt ){
-    StringBuffer sb;
-    initStringBuffer(&sb);
-    append(&sb, "SELECT docid, ");
-    appendList(&sb, v->nColumn, v->azContentColumn);
-    append(&sb, " FROM %_content");
-    if( idxNum!=QUERY_GENERIC ) append(&sb, " WHERE docid = ?");
-    rc = sql_prepare(v->db, v->zDb, v->zName, &c->pStmt,
-                     stringBufferData(&sb));
-    stringBufferDestroy(&sb);
-    if( rc!=SQLITE_OK ) return rc;
-    c->iCursorType = idxNum;
-  }else{
-    sqlite3_reset(c->pStmt);
-    assert( c->iCursorType==idxNum );
-  }
-
-  switch( idxNum ){
-    case QUERY_GENERIC:
-      break;
-
-    case QUERY_DOCID:
-      rc = sqlite3_bind_int64(c->pStmt, 1, sqlite3_value_int64(argv[0]));
-      if( rc!=SQLITE_OK ) return rc;
-      break;
-
-    default:   /* full-text search */
-    {
-      int iCol = idxNum-QUERY_FULLTEXT;
-      const char *zQuery = (const char *)sqlite3_value_text(argv[0]);
-      assert( idxNum<=QUERY_FULLTEXT+v->nColumn);
-      assert( argc==1 );
-      if( c->result.nData!=0 ){
-        /* This case happens if the same cursor is used repeatedly. */
-        dlrDestroy(&c->reader);
-        dataBufferReset(&c->result);
-      }else{
-        dataBufferInit(&c->result, 0);
-      }
-      rc = fulltextQuery(v, iCol, zQuery, -1, &c->result, &c->pExpr);
-      if( rc!=SQLITE_OK ) return rc;
-      if( c->result.nData!=0 ){
-        dlrInit(&c->reader, DL_DOCIDS, c->result.pData, c->result.nData);
-      }
-      break;
-    }
-  }
-
-  return fulltextNext(pCursor);
-}
-
-/* This is the xEof method of the virtual table.  The SQLite core
-** calls this routine to find out if it has reached the end of
-** a query's results set.
-*/
-static int fulltextEof(sqlite3_vtab_cursor *pCursor){
-  fulltext_cursor *c = (fulltext_cursor *) pCursor;
-  return c->eof;
-}
-
-/* This is the xColumn method of the virtual table.  The SQLite
-** core calls this method during a query when it needs the value
-** of a column from the virtual table.  This method needs to use
-** one of the sqlite3_result_*() routines to store the requested
-** value back in the pContext.
-*/
-static int fulltextColumn(sqlite3_vtab_cursor *pCursor,
-                          sqlite3_context *pContext, int idxCol){
-  fulltext_cursor *c = (fulltext_cursor *) pCursor;
-  fulltext_vtab *v = cursor_vtab(c);
-
-  if( idxCol<v->nColumn ){
-    sqlite3_value *pVal = sqlite3_column_value(c->pStmt, idxCol+1);
-    sqlite3_result_value(pContext, pVal);
-  }else if( idxCol==v->nColumn ){
-    /* The extra column whose name is the same as the table.
-    ** Return a blob which is a pointer to the cursor
-    */
-    sqlite3_result_blob(pContext, &c, sizeof(c), SQLITE_TRANSIENT);
-  }else if( idxCol==v->nColumn+1 ){
-    /* The docid column, which is an alias for rowid. */
-    sqlite3_value *pVal = sqlite3_column_value(c->pStmt, 0);
-    sqlite3_result_value(pContext, pVal);
-  }
-  return SQLITE_OK;
-}
-
-/* This is the xRowid method.  The SQLite core calls this routine to
-** retrieve the rowid for the current row of the result set.  fts3
-** exposes %_content.docid as the rowid for the virtual table.  The
-** rowid should be written to *pRowid.
-*/
-static int fulltextRowid(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
-  fulltext_cursor *c = (fulltext_cursor *) pCursor;
-
-  *pRowid = sqlite3_column_int64(c->pStmt, 0);
-  return SQLITE_OK;
-}
-
-/* Add all terms in [zText] to pendingTerms table.  If [iColumn] > 0,
-** we also store positions and offsets in the hash table using that
-** column number.
-*/
-static int buildTerms(fulltext_vtab *v, sqlite_int64 iDocid,
-                      const char *zText, int iColumn){
-  sqlite3_tokenizer *pTokenizer = v->pTokenizer;
-  sqlite3_tokenizer_cursor *pCursor;
-  const char *pToken;
-  int nTokenBytes;
-  int iStartOffset, iEndOffset, iPosition;
-  int rc;
-
-  rc = pTokenizer->pModule->xOpen(pTokenizer, zText, -1, &pCursor);
-  if( rc!=SQLITE_OK ) return rc;
-
-  pCursor->pTokenizer = pTokenizer;
-  while( SQLITE_OK==(rc=pTokenizer->pModule->xNext(pCursor,
-                                                   &pToken, &nTokenBytes,
-                                                   &iStartOffset, &iEndOffset,
-                                                   &iPosition)) ){
-    DLCollector *p;
-    int nData;                   /* Size of doclist before our update. */
-
-    /* Positions can't be negative; we use -1 as a terminator
-     * internally.  Token can't be NULL or empty. */
-    if( iPosition<0 || pToken == NULL || nTokenBytes == 0 ){
-      rc = SQLITE_ERROR;
-      break;
-    }
-
-    p = fts3HashFind(&v->pendingTerms, pToken, nTokenBytes);
-    if( p==NULL ){
-      nData = 0;
-      p = dlcNew(iDocid, DL_DEFAULT);
-      fts3HashInsert(&v->pendingTerms, pToken, nTokenBytes, p);
-
-      /* Overhead for our hash table entry, the key, and the value. */
-      v->nPendingData += sizeof(struct fts3HashElem)+sizeof(*p)+nTokenBytes;
-    }else{
-      nData = p->b.nData;
-      if( p->dlw.iPrevDocid!=iDocid ) dlcNext(p, iDocid);
-    }
-    if( iColumn>=0 ){
-      dlcAddPos(p, iColumn, iPosition, iStartOffset, iEndOffset);
-    }
-
-    /* Accumulate data added by dlcNew or dlcNext, and dlcAddPos. */
-    v->nPendingData += p->b.nData-nData;
-  }
-
-  /* TODO(shess) Check return?  Should this be able to cause errors at
-  ** this point?  Actually, same question about sqlite3_finalize(),
-  ** though one could argue that failure there means that the data is
-  ** not durable.  *ponder*
-  */
-  pTokenizer->pModule->xClose(pCursor);
-  if( SQLITE_DONE == rc ) return SQLITE_OK;
-  return rc;
-}
-
-/* Add doclists for all terms in [pValues] to pendingTerms table. */
-static int insertTerms(fulltext_vtab *v, sqlite_int64 iDocid,
-                       sqlite3_value **pValues){
-  int i;
-  for(i = 0; i < v->nColumn ; ++i){
-    char *zText = (char*)sqlite3_value_text(pValues[i]);
-    int rc = buildTerms(v, iDocid, zText, i);
-    if( rc!=SQLITE_OK ) return rc;
-  }
-  return SQLITE_OK;
-}
-
-/* Add empty doclists for all terms in the given row's content to
-** pendingTerms.
-*/
-static int deleteTerms(fulltext_vtab *v, sqlite_int64 iDocid){
-  const char **pValues;
-  int i, rc;
-
-  /* TODO(shess) Should we allow such tables at all? */
-  if( DL_DEFAULT==DL_DOCIDS ) return SQLITE_ERROR;
-
-  rc = content_select(v, iDocid, &pValues);
-  if( rc!=SQLITE_OK ) return rc;
-
-  for(i = 0 ; i < v->nColumn; ++i) {
-    rc = buildTerms(v, iDocid, pValues[i], -1);
-    if( rc!=SQLITE_OK ) break;
-  }
-
-  freeStringArray(v->nColumn, pValues);
-  return SQLITE_OK;
-}
-
-/* TODO(shess) Refactor the code to remove this forward decl. */
-static int initPendingTerms(fulltext_vtab *v, sqlite_int64 iDocid);
-
-/* Insert a row into the %_content table; set *piDocid to be the ID of the
-** new row.  Add doclists for terms to pendingTerms.
-*/
-static int index_insert(fulltext_vtab *v, sqlite3_value *pRequestDocid,
-                        sqlite3_value **pValues, sqlite_int64 *piDocid){
-  int rc;
-
-  rc = content_insert(v, pRequestDocid, pValues);  /* execute an SQL INSERT */
-  if( rc!=SQLITE_OK ) return rc;
-
-  /* docid column is an alias for rowid. */
-  *piDocid = sqlite3_last_insert_rowid(v->db);
-  rc = initPendingTerms(v, *piDocid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  return insertTerms(v, *piDocid, pValues);
-}
-
-/* Delete a row from the %_content table; add empty doclists for terms
-** to pendingTerms.
-*/
-static int index_delete(fulltext_vtab *v, sqlite_int64 iRow){
-  int rc = initPendingTerms(v, iRow);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = deleteTerms(v, iRow);
-  if( rc!=SQLITE_OK ) return rc;
-
-  return content_delete(v, iRow);  /* execute an SQL DELETE */
-}
-
-/* Update a row in the %_content table; add delete doclists to
-** pendingTerms for old terms not in the new data, add insert doclists
-** to pendingTerms for terms in the new data.
-*/
-static int index_update(fulltext_vtab *v, sqlite_int64 iRow,
-                        sqlite3_value **pValues){
-  int rc = initPendingTerms(v, iRow);
-  if( rc!=SQLITE_OK ) return rc;
-
-  /* Generate an empty doclist for each term that previously appeared in this
-   * row. */
-  rc = deleteTerms(v, iRow);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = content_update(v, pValues, iRow);  /* execute an SQL UPDATE */
-  if( rc!=SQLITE_OK ) return rc;
-
-  /* Now add positions for terms which appear in the updated row. */
-  return insertTerms(v, iRow, pValues);
-}
-
-/*******************************************************************/
-/* InteriorWriter is used to collect terms and block references into
-** interior nodes in %_segments.  See commentary at top of file for
-** format.
-*/
-
-/* How large interior nodes can grow. */
-#define INTERIOR_MAX 2048
-
-/* Minimum number of terms per interior node (except the root). This
-** prevents large terms from making the tree too skinny - must be >0
-** so that the tree always makes progress.  Note that the min tree
-** fanout will be INTERIOR_MIN_TERMS+1.
-*/
-#define INTERIOR_MIN_TERMS 7
-#if INTERIOR_MIN_TERMS<1
-# error INTERIOR_MIN_TERMS must be greater than 0.
-#endif
-
-/* ROOT_MAX controls how much data is stored inline in the segment
-** directory.
-*/
-/* TODO(shess) Push ROOT_MAX down to whoever is writing things.  It's
-** only here so that interiorWriterRootInfo() and leafWriterRootInfo()
-** can both see it, but if the caller passed it in, we wouldn't even
-** need a define.
-*/
-#define ROOT_MAX 1024
-#if ROOT_MAX<VARINT_MAX*2
-# error ROOT_MAX must have enough space for a header.
-#endif
-
-/* InteriorBlock stores a linked-list of interior blocks while a lower
-** layer is being constructed.
-*/
-typedef struct InteriorBlock {
-  DataBuffer term;           /* Leftmost term in block's subtree. */
-  DataBuffer data;           /* Accumulated data for the block. */
-  struct InteriorBlock *next;
-} InteriorBlock;
-
-static InteriorBlock *interiorBlockNew(int iHeight, sqlite_int64 iChildBlock,
-                                       const char *pTerm, int nTerm){
-  InteriorBlock *block = sqlite3_malloc(sizeof(InteriorBlock));
-  char c[VARINT_MAX+VARINT_MAX];
-  int n;
-
-  if( block ){
-    memset(block, 0, sizeof(*block));
-    dataBufferInit(&block->term, 0);
-    dataBufferReplace(&block->term, pTerm, nTerm);
-
-    n = fts3PutVarint(c, iHeight);
-    n += fts3PutVarint(c+n, iChildBlock);
-    dataBufferInit(&block->data, INTERIOR_MAX);
-    dataBufferReplace(&block->data, c, n);
-  }
-  return block;
-}
-
-#ifndef NDEBUG
-/* Verify that the data is readable as an interior node. */
-static void interiorBlockValidate(InteriorBlock *pBlock){
-  const char *pData = pBlock->data.pData;
-  int nData = pBlock->data.nData;
-  int n, iDummy;
-  sqlite_int64 iBlockid;
-
-  assert( nData>0 );
-  assert( pData!=0 );
-  assert( pData+nData>pData );
-
-  /* Must lead with height of node as a varint(n), n>0 */
-  n = fts3GetVarint32(pData, &iDummy);
-  assert( n>0 );
-  assert( iDummy>0 );
-  assert( n<nData );
-  pData += n;
-  nData -= n;
-
-  /* Must contain iBlockid. */
-  n = fts3GetVarint(pData, &iBlockid);
-  assert( n>0 );
-  assert( n<=nData );
-  pData += n;
-  nData -= n;
-
-  /* Zero or more terms of positive length */
-  if( nData!=0 ){
-    /* First term is not delta-encoded. */
-    n = fts3GetVarint32(pData, &iDummy);
-    assert( n>0 );
-    assert( iDummy>0 );
-    assert( n+iDummy>0);
-    assert( n+iDummy<=nData );
-    pData += n+iDummy;
-    nData -= n+iDummy;
-
-    /* Following terms delta-encoded. */
-    while( nData!=0 ){
-      /* Length of shared prefix. */
-      n = fts3GetVarint32(pData, &iDummy);
-      assert( n>0 );
-      assert( iDummy>=0 );
-      assert( n<nData );
-      pData += n;
-      nData -= n;
-
-      /* Length and data of distinct suffix. */
-      n = fts3GetVarint32(pData, &iDummy);
-      assert( n>0 );
-      assert( iDummy>0 );
-      assert( n+iDummy>0);
-      assert( n+iDummy<=nData );
-      pData += n+iDummy;
-      nData -= n+iDummy;
-    }
-  }
-}
-#define ASSERT_VALID_INTERIOR_BLOCK(x) interiorBlockValidate(x)
-#else
-#define ASSERT_VALID_INTERIOR_BLOCK(x) assert( 1 )
-#endif
-
-typedef struct InteriorWriter {
-  int iHeight;                   /* from 0 at leaves. */
-  InteriorBlock *first, *last;
-  struct InteriorWriter *parentWriter;
-
-  DataBuffer term;               /* Last term written to block "last". */
-  sqlite_int64 iOpeningChildBlock; /* First child block in block "last". */
-#ifndef NDEBUG
-  sqlite_int64 iLastChildBlock;  /* for consistency checks. */
-#endif
-} InteriorWriter;
-
-/* Initialize an interior node where pTerm[nTerm] marks the leftmost
-** term in the tree.  iChildBlock is the leftmost child block at the
-** next level down the tree.
-*/
-static void interiorWriterInit(int iHeight, const char *pTerm, int nTerm,
-                               sqlite_int64 iChildBlock,
-                               InteriorWriter *pWriter){
-  InteriorBlock *block;
-  assert( iHeight>0 );
-  CLEAR(pWriter);
-
-  pWriter->iHeight = iHeight;
-  pWriter->iOpeningChildBlock = iChildBlock;
-#ifndef NDEBUG
-  pWriter->iLastChildBlock = iChildBlock;
-#endif
-  block = interiorBlockNew(iHeight, iChildBlock, pTerm, nTerm);
-  pWriter->last = pWriter->first = block;
-  ASSERT_VALID_INTERIOR_BLOCK(pWriter->last);
-  dataBufferInit(&pWriter->term, 0);
-}
-
-/* Append the child node rooted at iChildBlock to the interior node,
-** with pTerm[nTerm] as the leftmost term in iChildBlock's subtree.
-*/
-static void interiorWriterAppend(InteriorWriter *pWriter,
-                                 const char *pTerm, int nTerm,
-                                 sqlite_int64 iChildBlock){
-  char c[VARINT_MAX+VARINT_MAX];
-  int n, nPrefix = 0;
-
-  ASSERT_VALID_INTERIOR_BLOCK(pWriter->last);
-
-  /* The first term written into an interior node is actually
-  ** associated with the second child added (the first child was added
-  ** in interiorWriterInit, or in the if clause at the bottom of this
-  ** function).  That term gets encoded straight up, with nPrefix left
-  ** at 0.
-  */
-  if( pWriter->term.nData==0 ){
-    n = fts3PutVarint(c, nTerm);
-  }else{
-    while( nPrefix<pWriter->term.nData &&
-           pTerm[nPrefix]==pWriter->term.pData[nPrefix] ){
-      nPrefix++;
-    }
-
-    n = fts3PutVarint(c, nPrefix);
-    n += fts3PutVarint(c+n, nTerm-nPrefix);
-  }
-
-#ifndef NDEBUG
-  pWriter->iLastChildBlock++;
-#endif
-  assert( pWriter->iLastChildBlock==iChildBlock );
-
-  /* Overflow to a new block if the new term makes the current block
-  ** too big, and the current block already has enough terms.
-  */
-  if( pWriter->last->data.nData+n+nTerm-nPrefix>INTERIOR_MAX &&
-      iChildBlock-pWriter->iOpeningChildBlock>INTERIOR_MIN_TERMS ){
-    pWriter->last->next = interiorBlockNew(pWriter->iHeight, iChildBlock,
-                                           pTerm, nTerm);
-    pWriter->last = pWriter->last->next;
-    pWriter->iOpeningChildBlock = iChildBlock;
-    dataBufferReset(&pWriter->term);
-  }else{
-    dataBufferAppend2(&pWriter->last->data, c, n,
-                      pTerm+nPrefix, nTerm-nPrefix);
-    dataBufferReplace(&pWriter->term, pTerm, nTerm);
-  }
-  ASSERT_VALID_INTERIOR_BLOCK(pWriter->last);
-}
-
-/* Free the space used by pWriter, including the linked-list of
-** InteriorBlocks, and parentWriter, if present.
-*/
-static int interiorWriterDestroy(InteriorWriter *pWriter){
-  InteriorBlock *block = pWriter->first;
-
-  while( block!=NULL ){
-    InteriorBlock *b = block;
-    block = block->next;
-    dataBufferDestroy(&b->term);
-    dataBufferDestroy(&b->data);
-    sqlite3_free(b);
-  }
-  if( pWriter->parentWriter!=NULL ){
-    interiorWriterDestroy(pWriter->parentWriter);
-    sqlite3_free(pWriter->parentWriter);
-  }
-  dataBufferDestroy(&pWriter->term);
-  SCRAMBLE(pWriter);
-  return SQLITE_OK;
-}
-
-/* If pWriter can fit entirely in ROOT_MAX, return it as the root info
-** directly, leaving *piEndBlockid unchanged.  Otherwise, flush
-** pWriter to %_segments, building a new layer of interior nodes, and
-** recursively ask for their root into.
-*/
-static int interiorWriterRootInfo(fulltext_vtab *v, InteriorWriter *pWriter,
-                                  char **ppRootInfo, int *pnRootInfo,
-                                  sqlite_int64 *piEndBlockid){
-  InteriorBlock *block = pWriter->first;
-  sqlite_int64 iBlockid = 0;
-  int rc;
-
-  /* If we can fit the segment inline */
-  if( block==pWriter->last && block->data.nData<ROOT_MAX ){
-    *ppRootInfo = block->data.pData;
-    *pnRootInfo = block->data.nData;
-    return SQLITE_OK;
-  }
-
-  /* Flush the first block to %_segments, and create a new level of
-  ** interior node.
-  */
-  ASSERT_VALID_INTERIOR_BLOCK(block);
-  rc = block_insert(v, block->data.pData, block->data.nData, &iBlockid);
-  if( rc!=SQLITE_OK ) return rc;
-  *piEndBlockid = iBlockid;
-
-  pWriter->parentWriter = sqlite3_malloc(sizeof(*pWriter->parentWriter));
-  interiorWriterInit(pWriter->iHeight+1,
-                     block->term.pData, block->term.nData,
-                     iBlockid, pWriter->parentWriter);
-
-  /* Flush additional blocks and append to the higher interior
-  ** node.
-  */
-  for(block=block->next; block!=NULL; block=block->next){
-    ASSERT_VALID_INTERIOR_BLOCK(block);
-    rc = block_insert(v, block->data.pData, block->data.nData, &iBlockid);
-    if( rc!=SQLITE_OK ) return rc;
-    *piEndBlockid = iBlockid;
-
-    interiorWriterAppend(pWriter->parentWriter,
-                         block->term.pData, block->term.nData, iBlockid);
-  }
-
-  /* Parent node gets the chance to be the root. */
-  return interiorWriterRootInfo(v, pWriter->parentWriter,
-                                ppRootInfo, pnRootInfo, piEndBlockid);
-}
-
-/****************************************************************/
-/* InteriorReader is used to read off the data from an interior node
-** (see comment at top of file for the format).
-*/
-typedef struct InteriorReader {
-  const char *pData;
-  int nData;
-
-  DataBuffer term;          /* previous term, for decoding term delta. */
-
-  sqlite_int64 iBlockid;
-} InteriorReader;
-
-static void interiorReaderDestroy(InteriorReader *pReader){
-  dataBufferDestroy(&pReader->term);
-  SCRAMBLE(pReader);
-}
-
-/* TODO(shess) The assertions are great, but what if we're in NDEBUG
-** and the blob is empty or otherwise contains suspect data?
-*/
-static void interiorReaderInit(const char *pData, int nData,
-                               InteriorReader *pReader){
-  int n, nTerm;
-
-  /* Require at least the leading flag byte */
-  assert( nData>0 );
-  assert( pData[0]!='\0' );
-
-  CLEAR(pReader);
-
-  /* Decode the base blockid, and set the cursor to the first term. */
-  n = fts3GetVarint(pData+1, &pReader->iBlockid);
-  assert( 1+n<=nData );
-  pReader->pData = pData+1+n;
-  pReader->nData = nData-(1+n);
-
-  /* A single-child interior node (such as when a leaf node was too
-  ** large for the segment directory) won't have any terms.
-  ** Otherwise, decode the first term.
-  */
-  if( pReader->nData==0 ){
-    dataBufferInit(&pReader->term, 0);
-  }else{
-    n = fts3GetVarint32(pReader->pData, &nTerm);
-    dataBufferInit(&pReader->term, nTerm);
-    dataBufferReplace(&pReader->term, pReader->pData+n, nTerm);
-    assert( n+nTerm<=pReader->nData );
-    pReader->pData += n+nTerm;
-    pReader->nData -= n+nTerm;
-  }
-}
-
-static int interiorReaderAtEnd(InteriorReader *pReader){
-  return pReader->term.nData==0;
-}
-
-static sqlite_int64 interiorReaderCurrentBlockid(InteriorReader *pReader){
-  return pReader->iBlockid;
-}
-
-static int interiorReaderTermBytes(InteriorReader *pReader){
-  assert( !interiorReaderAtEnd(pReader) );
-  return pReader->term.nData;
-}
-static const char *interiorReaderTerm(InteriorReader *pReader){
-  assert( !interiorReaderAtEnd(pReader) );
-  return pReader->term.pData;
-}
-
-/* Step forward to the next term in the node. */
-static void interiorReaderStep(InteriorReader *pReader){
-  assert( !interiorReaderAtEnd(pReader) );
-
-  /* If the last term has been read, signal eof, else construct the
-  ** next term.
-  */
-  if( pReader->nData==0 ){
-    dataBufferReset(&pReader->term);
-  }else{
-    int n, nPrefix, nSuffix;
-
-    n = fts3GetVarint32(pReader->pData, &nPrefix);
-    n += fts3GetVarint32(pReader->pData+n, &nSuffix);
-
-    /* Truncate the current term and append suffix data. */
-    pReader->term.nData = nPrefix;
-    dataBufferAppend(&pReader->term, pReader->pData+n, nSuffix);
-
-    assert( n+nSuffix<=pReader->nData );
-    pReader->pData += n+nSuffix;
-    pReader->nData -= n+nSuffix;
-  }
-  pReader->iBlockid++;
-}
-
-/* Compare the current term to pTerm[nTerm], returning strcmp-style
-** results.  If isPrefix, equality means equal through nTerm bytes.
-*/
-static int interiorReaderTermCmp(InteriorReader *pReader,
-                                 const char *pTerm, int nTerm, int isPrefix){
-  const char *pReaderTerm = interiorReaderTerm(pReader);
-  int nReaderTerm = interiorReaderTermBytes(pReader);
-  int c, n = nReaderTerm<nTerm ? nReaderTerm : nTerm;
-
-  if( n==0 ){
-    if( nReaderTerm>0 ) return -1;
-    if( nTerm>0 ) return 1;
-    return 0;
-  }
-
-  c = memcmp(pReaderTerm, pTerm, n);
-  if( c!=0 ) return c;
-  if( isPrefix && n==nTerm ) return 0;
-  return nReaderTerm - nTerm;
-}
-
-/****************************************************************/
-/* LeafWriter is used to collect terms and associated doclist data
-** into leaf blocks in %_segments (see top of file for format info).
-** Expected usage is:
-**
-** LeafWriter writer;
-** leafWriterInit(0, 0, &writer);
-** while( sorted_terms_left_to_process ){
-**   // data is doclist data for that term.
-**   rc = leafWriterStep(v, &writer, pTerm, nTerm, pData, nData);
-**   if( rc!=SQLITE_OK ) goto err;
-** }
-** rc = leafWriterFinalize(v, &writer);
-**err:
-** leafWriterDestroy(&writer);
-** return rc;
-**
-** leafWriterStep() may write a collected leaf out to %_segments.
-** leafWriterFinalize() finishes writing any buffered data and stores
-** a root node in %_segdir.  leafWriterDestroy() frees all buffers and
-** InteriorWriters allocated as part of writing this segment.
-**
-** TODO(shess) Document leafWriterStepMerge().
-*/
-
-/* Put terms with data this big in their own block. */
-#define STANDALONE_MIN 1024
-
-/* Keep leaf blocks below this size. */
-#define LEAF_MAX 2048
-
-typedef struct LeafWriter {
-  int iLevel;
-  int idx;
-  sqlite_int64 iStartBlockid;     /* needed to create the root info */
-  sqlite_int64 iEndBlockid;       /* when we're done writing. */
-
-  DataBuffer term;                /* previous encoded term */
-  DataBuffer data;                /* encoding buffer */
-
-  /* bytes of first term in the current node which distinguishes that
-  ** term from the last term of the previous node.
-  */
-  int nTermDistinct;
-
-  InteriorWriter parentWriter;    /* if we overflow */
-  int has_parent;
-} LeafWriter;
-
-static void leafWriterInit(int iLevel, int idx, LeafWriter *pWriter){
-  CLEAR(pWriter);
-  pWriter->iLevel = iLevel;
-  pWriter->idx = idx;
-
-  dataBufferInit(&pWriter->term, 32);
-
-  /* Start out with a reasonably sized block, though it can grow. */
-  dataBufferInit(&pWriter->data, LEAF_MAX);
-}
-
-#ifndef NDEBUG
-/* Verify that the data is readable as a leaf node. */
-static void leafNodeValidate(const char *pData, int nData){
-  int n, iDummy;
-
-  if( nData==0 ) return;
-  assert( nData>0 );
-  assert( pData!=0 );
-  assert( pData+nData>pData );
-
-  /* Must lead with a varint(0) */
-  n = fts3GetVarint32(pData, &iDummy);
-  assert( iDummy==0 );
-  assert( n>0 );
-  assert( n<nData );
-  pData += n;
-  nData -= n;
-
-  /* Leading term length and data must fit in buffer. */
-  n = fts3GetVarint32(pData, &iDummy);
-  assert( n>0 );
-  assert( iDummy>0 );
-  assert( n+iDummy>0 );
-  assert( n+iDummy<nData );
-  pData += n+iDummy;
-  nData -= n+iDummy;
-
-  /* Leading term's doclist length and data must fit. */
-  n = fts3GetVarint32(pData, &iDummy);
-  assert( n>0 );
-  assert( iDummy>0 );
-  assert( n+iDummy>0 );
-  assert( n+iDummy<=nData );
-  ASSERT_VALID_DOCLIST(DL_DEFAULT, pData+n, iDummy, NULL);
-  pData += n+iDummy;
-  nData -= n+iDummy;
-
-  /* Verify that trailing terms and doclists also are readable. */
-  while( nData!=0 ){
-    n = fts3GetVarint32(pData, &iDummy);
-    assert( n>0 );
-    assert( iDummy>=0 );
-    assert( n<nData );
-    pData += n;
-    nData -= n;
-    n = fts3GetVarint32(pData, &iDummy);
-    assert( n>0 );
-    assert( iDummy>0 );
-    assert( n+iDummy>0 );
-    assert( n+iDummy<nData );
-    pData += n+iDummy;
-    nData -= n+iDummy;
-
-    n = fts3GetVarint32(pData, &iDummy);
-    assert( n>0 );
-    assert( iDummy>0 );
-    assert( n+iDummy>0 );
-    assert( n+iDummy<=nData );
-    ASSERT_VALID_DOCLIST(DL_DEFAULT, pData+n, iDummy, NULL);
-    pData += n+iDummy;
-    nData -= n+iDummy;
-  }
-}
-#define ASSERT_VALID_LEAF_NODE(p, n) leafNodeValidate(p, n)
-#else
-#define ASSERT_VALID_LEAF_NODE(p, n) assert( 1 )
-#endif
-
-/* Flush the current leaf node to %_segments, and adding the resulting
-** blockid and the starting term to the interior node which will
-** contain it.
-*/
-static int leafWriterInternalFlush(fulltext_vtab *v, LeafWriter *pWriter,
-                                   int iData, int nData){
-  sqlite_int64 iBlockid = 0;
-  const char *pStartingTerm;
-  int nStartingTerm, rc, n;
-
-  /* Must have the leading varint(0) flag, plus at least some
-  ** valid-looking data.
-  */
-  assert( nData>2 );
-  assert( iData>=0 );
-  assert( iData+nData<=pWriter->data.nData );
-  ASSERT_VALID_LEAF_NODE(pWriter->data.pData+iData, nData);
-
-  rc = block_insert(v, pWriter->data.pData+iData, nData, &iBlockid);
-  if( rc!=SQLITE_OK ) return rc;
-  assert( iBlockid!=0 );
-
-  /* Reconstruct the first term in the leaf for purposes of building
-  ** the interior node.
-  */
-  n = fts3GetVarint32(pWriter->data.pData+iData+1, &nStartingTerm);
-  pStartingTerm = pWriter->data.pData+iData+1+n;
-  assert( pWriter->data.nData>iData+1+n+nStartingTerm );
-  assert( pWriter->nTermDistinct>0 );
-  assert( pWriter->nTermDistinct<=nStartingTerm );
-  nStartingTerm = pWriter->nTermDistinct;
-
-  if( pWriter->has_parent ){
-    interiorWriterAppend(&pWriter->parentWriter,
-                         pStartingTerm, nStartingTerm, iBlockid);
-  }else{
-    interiorWriterInit(1, pStartingTerm, nStartingTerm, iBlockid,
-                       &pWriter->parentWriter);
-    pWriter->has_parent = 1;
-  }
-
-  /* Track the span of this segment's leaf nodes. */
-  if( pWriter->iEndBlockid==0 ){
-    pWriter->iEndBlockid = pWriter->iStartBlockid = iBlockid;
-  }else{
-    pWriter->iEndBlockid++;
-    assert( iBlockid==pWriter->iEndBlockid );
-  }
-
-  return SQLITE_OK;
-}
-static int leafWriterFlush(fulltext_vtab *v, LeafWriter *pWriter){
-  int rc = leafWriterInternalFlush(v, pWriter, 0, pWriter->data.nData);
-  if( rc!=SQLITE_OK ) return rc;
-
-  /* Re-initialize the output buffer. */
-  dataBufferReset(&pWriter->data);
-
-  return SQLITE_OK;
-}
-
-/* Fetch the root info for the segment.  If the entire leaf fits
-** within ROOT_MAX, then it will be returned directly, otherwise it
-** will be flushed and the root info will be returned from the
-** interior node.  *piEndBlockid is set to the blockid of the last
-** interior or leaf node written to disk (0 if none are written at
-** all).
-*/
-static int leafWriterRootInfo(fulltext_vtab *v, LeafWriter *pWriter,
-                              char **ppRootInfo, int *pnRootInfo,
-                              sqlite_int64 *piEndBlockid){
-  /* we can fit the segment entirely inline */
-  if( !pWriter->has_parent && pWriter->data.nData<ROOT_MAX ){
-    *ppRootInfo = pWriter->data.pData;
-    *pnRootInfo = pWriter->data.nData;
-    *piEndBlockid = 0;
-    return SQLITE_OK;
-  }
-
-  /* Flush remaining leaf data. */
-  if( pWriter->data.nData>0 ){
-    int rc = leafWriterFlush(v, pWriter);
-    if( rc!=SQLITE_OK ) return rc;
-  }
-
-  /* We must have flushed a leaf at some point. */
-  assert( pWriter->has_parent );
-
-  /* Tenatively set the end leaf blockid as the end blockid.  If the
-  ** interior node can be returned inline, this will be the final
-  ** blockid, otherwise it will be overwritten by
-  ** interiorWriterRootInfo().
-  */
-  *piEndBlockid = pWriter->iEndBlockid;
-
-  return interiorWriterRootInfo(v, &pWriter->parentWriter,
-                                ppRootInfo, pnRootInfo, piEndBlockid);
-}
-
-/* Collect the rootInfo data and store it into the segment directory.
-** This has the effect of flushing the segment's leaf data to
-** %_segments, and also flushing any interior nodes to %_segments.
-*/
-static int leafWriterFinalize(fulltext_vtab *v, LeafWriter *pWriter){
-  sqlite_int64 iEndBlockid;
-  char *pRootInfo;
-  int rc, nRootInfo;
-
-  rc = leafWriterRootInfo(v, pWriter, &pRootInfo, &nRootInfo, &iEndBlockid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  /* Don't bother storing an entirely empty segment. */
-  if( iEndBlockid==0 && nRootInfo==0 ) return SQLITE_OK;
-
-  return segdir_set(v, pWriter->iLevel, pWriter->idx,
-                    pWriter->iStartBlockid, pWriter->iEndBlockid,
-                    iEndBlockid, pRootInfo, nRootInfo);
-}
-
-static void leafWriterDestroy(LeafWriter *pWriter){
-  if( pWriter->has_parent ) interiorWriterDestroy(&pWriter->parentWriter);
-  dataBufferDestroy(&pWriter->term);
-  dataBufferDestroy(&pWriter->data);
-}
-
-/* Encode a term into the leafWriter, delta-encoding as appropriate.
-** Returns the length of the new term which distinguishes it from the
-** previous term, which can be used to set nTermDistinct when a node
-** boundary is crossed.
-*/
-static int leafWriterEncodeTerm(LeafWriter *pWriter,
-                                const char *pTerm, int nTerm){
-  char c[VARINT_MAX+VARINT_MAX];
-  int n, nPrefix = 0;
-
-  assert( nTerm>0 );
-  while( nPrefix<pWriter->term.nData &&
-         pTerm[nPrefix]==pWriter->term.pData[nPrefix] ){
-    nPrefix++;
-    /* Failing this implies that the terms weren't in order. */
-    assert( nPrefix<nTerm );
-  }
-
-  if( pWriter->data.nData==0 ){
-    /* Encode the node header and leading term as:
-    **  varint(0)
-    **  varint(nTerm)
-    **  char pTerm[nTerm]
-    */
-    n = fts3PutVarint(c, '\0');
-    n += fts3PutVarint(c+n, nTerm);
-    dataBufferAppend2(&pWriter->data, c, n, pTerm, nTerm);
-  }else{
-    /* Delta-encode the term as:
-    **  varint(nPrefix)
-    **  varint(nSuffix)
-    **  char pTermSuffix[nSuffix]
-    */
-    n = fts3PutVarint(c, nPrefix);
-    n += fts3PutVarint(c+n, nTerm-nPrefix);
-    dataBufferAppend2(&pWriter->data, c, n, pTerm+nPrefix, nTerm-nPrefix);
-  }
-  dataBufferReplace(&pWriter->term, pTerm, nTerm);
-
-  return nPrefix+1;
-}
-
-/* Used to avoid a memmove when a large amount of doclist data is in
-** the buffer.  This constructs a node and term header before
-** iDoclistData and flushes the resulting complete node using
-** leafWriterInternalFlush().
-*/
-static int leafWriterInlineFlush(fulltext_vtab *v, LeafWriter *pWriter,
-                                 const char *pTerm, int nTerm,
-                                 int iDoclistData){
-  char c[VARINT_MAX+VARINT_MAX];
-  int iData, n = fts3PutVarint(c, 0);
-  n += fts3PutVarint(c+n, nTerm);
-
-  /* There should always be room for the header.  Even if pTerm shared
-  ** a substantial prefix with the previous term, the entire prefix
-  ** could be constructed from earlier data in the doclist, so there
-  ** should be room.
-  */
-  assert( iDoclistData>=n+nTerm );
-
-  iData = iDoclistData-(n+nTerm);
-  memcpy(pWriter->data.pData+iData, c, n);
-  memcpy(pWriter->data.pData+iData+n, pTerm, nTerm);
-
-  return leafWriterInternalFlush(v, pWriter, iData, pWriter->data.nData-iData);
-}
-
-/* Push pTerm[nTerm] along with the doclist data to the leaf layer of
-** %_segments.
-*/
-static int leafWriterStepMerge(fulltext_vtab *v, LeafWriter *pWriter,
-                               const char *pTerm, int nTerm,
-                               DLReader *pReaders, int nReaders){
-  char c[VARINT_MAX+VARINT_MAX];
-  int iTermData = pWriter->data.nData, iDoclistData;
-  int i, nData, n, nActualData, nActual, rc, nTermDistinct;
-
-  ASSERT_VALID_LEAF_NODE(pWriter->data.pData, pWriter->data.nData);
-  nTermDistinct = leafWriterEncodeTerm(pWriter, pTerm, nTerm);
-
-  /* Remember nTermDistinct if opening a new node. */
-  if( iTermData==0 ) pWriter->nTermDistinct = nTermDistinct;
-
-  iDoclistData = pWriter->data.nData;
-
-  /* Estimate the length of the merged doclist so we can leave space
-  ** to encode it.
-  */
-  for(i=0, nData=0; i<nReaders; i++){
-    nData += dlrAllDataBytes(&pReaders[i]);
-  }
-  n = fts3PutVarint(c, nData);
-  dataBufferAppend(&pWriter->data, c, n);
-
-  docListMerge(&pWriter->data, pReaders, nReaders);
-  ASSERT_VALID_DOCLIST(DL_DEFAULT,
-                       pWriter->data.pData+iDoclistData+n,
-                       pWriter->data.nData-iDoclistData-n, NULL);
-
-  /* The actual amount of doclist data at this point could be smaller
-  ** than the length we encoded.  Additionally, the space required to
-  ** encode this length could be smaller.  For small doclists, this is
-  ** not a big deal, we can just use memmove() to adjust things.
-  */
-  nActualData = pWriter->data.nData-(iDoclistData+n);
-  nActual = fts3PutVarint(c, nActualData);
-  assert( nActualData<=nData );
-  assert( nActual<=n );
-
-  /* If the new doclist is big enough for force a standalone leaf
-  ** node, we can immediately flush it inline without doing the
-  ** memmove().
-  */
-  /* TODO(shess) This test matches leafWriterStep(), which does this
-  ** test before it knows the cost to varint-encode the term and
-  ** doclist lengths.  At some point, change to
-  ** pWriter->data.nData-iTermData>STANDALONE_MIN.
-  */
-  if( nTerm+nActualData>STANDALONE_MIN ){
-    /* Push leaf node from before this term. */
-    if( iTermData>0 ){
-      rc = leafWriterInternalFlush(v, pWriter, 0, iTermData);
-      if( rc!=SQLITE_OK ) return rc;
-
-      pWriter->nTermDistinct = nTermDistinct;
-    }
-
-    /* Fix the encoded doclist length. */
-    iDoclistData += n - nActual;
-    memcpy(pWriter->data.pData+iDoclistData, c, nActual);
-
-    /* Push the standalone leaf node. */
-    rc = leafWriterInlineFlush(v, pWriter, pTerm, nTerm, iDoclistData);
-    if( rc!=SQLITE_OK ) return rc;
-
-    /* Leave the node empty. */
-    dataBufferReset(&pWriter->data);
-
-    return rc;
-  }
-
-  /* At this point, we know that the doclist was small, so do the
-  ** memmove if indicated.
-  */
-  if( nActual<n ){
-    memmove(pWriter->data.pData+iDoclistData+nActual,
-            pWriter->data.pData+iDoclistData+n,
-            pWriter->data.nData-(iDoclistData+n));
-    pWriter->data.nData -= n-nActual;
-  }
-
-  /* Replace written length with actual length. */
-  memcpy(pWriter->data.pData+iDoclistData, c, nActual);
-
-  /* If the node is too large, break things up. */
-  /* TODO(shess) This test matches leafWriterStep(), which does this
-  ** test before it knows the cost to varint-encode the term and
-  ** doclist lengths.  At some point, change to
-  ** pWriter->data.nData>LEAF_MAX.
-  */
-  if( iTermData+nTerm+nActualData>LEAF_MAX ){
-    /* Flush out the leading data as a node */
-    rc = leafWriterInternalFlush(v, pWriter, 0, iTermData);
-    if( rc!=SQLITE_OK ) return rc;
-
-    pWriter->nTermDistinct = nTermDistinct;
-
-    /* Rebuild header using the current term */
-    n = fts3PutVarint(pWriter->data.pData, 0);
-    n += fts3PutVarint(pWriter->data.pData+n, nTerm);
-    memcpy(pWriter->data.pData+n, pTerm, nTerm);
-    n += nTerm;
-
-    /* There should always be room, because the previous encoding
-    ** included all data necessary to construct the term.
-    */
-    assert( n<iDoclistData );
-    /* So long as STANDALONE_MIN is half or less of LEAF_MAX, the
-    ** following memcpy() is safe (as opposed to needing a memmove).
-    */
-    assert( 2*STANDALONE_MIN<=LEAF_MAX );
-    assert( n+pWriter->data.nData-iDoclistData<iDoclistData );
-    memcpy(pWriter->data.pData+n,
-           pWriter->data.pData+iDoclistData,
-           pWriter->data.nData-iDoclistData);
-    pWriter->data.nData -= iDoclistData-n;
-  }
-  ASSERT_VALID_LEAF_NODE(pWriter->data.pData, pWriter->data.nData);
-
-  return SQLITE_OK;
-}
-
-/* Push pTerm[nTerm] along with the doclist data to the leaf layer of
-** %_segments.
-*/
-/* TODO(shess) Revise writeZeroSegment() so that doclists are
-** constructed directly in pWriter->data.
-*/
-static int leafWriterStep(fulltext_vtab *v, LeafWriter *pWriter,
-                          const char *pTerm, int nTerm,
-                          const char *pData, int nData){
-  int rc;
-  DLReader reader;
-
-  dlrInit(&reader, DL_DEFAULT, pData, nData);
-  rc = leafWriterStepMerge(v, pWriter, pTerm, nTerm, &reader, 1);
-  dlrDestroy(&reader);
-
-  return rc;
-}
-
-
-/****************************************************************/
-/* LeafReader is used to iterate over an individual leaf node. */
-typedef struct LeafReader {
-  DataBuffer term;          /* copy of current term. */
-
-  const char *pData;        /* data for current term. */
-  int nData;
-} LeafReader;
-
-static void leafReaderDestroy(LeafReader *pReader){
-  dataBufferDestroy(&pReader->term);
-  SCRAMBLE(pReader);
-}
-
-static int leafReaderAtEnd(LeafReader *pReader){
-  return pReader->nData<=0;
-}
-
-/* Access the current term. */
-static int leafReaderTermBytes(LeafReader *pReader){
-  return pReader->term.nData;
-}
-static const char *leafReaderTerm(LeafReader *pReader){
-  assert( pReader->term.nData>0 );
-  return pReader->term.pData;
-}
-
-/* Access the doclist data for the current term. */
-static int leafReaderDataBytes(LeafReader *pReader){
-  int nData;
-  assert( pReader->term.nData>0 );
-  fts3GetVarint32(pReader->pData, &nData);
-  return nData;
-}
-static const char *leafReaderData(LeafReader *pReader){
-  int n, nData;
-  assert( pReader->term.nData>0 );
-  n = fts3GetVarint32(pReader->pData, &nData);
-  return pReader->pData+n;
-}
-
-static void leafReaderInit(const char *pData, int nData,
-                           LeafReader *pReader){
-  int nTerm, n;
-
-  assert( nData>0 );
-  assert( pData[0]=='\0' );
-
-  CLEAR(pReader);
-
-  /* Read the first term, skipping the header byte. */
-  n = fts3GetVarint32(pData+1, &nTerm);
-  dataBufferInit(&pReader->term, nTerm);
-  dataBufferReplace(&pReader->term, pData+1+n, nTerm);
-
-  /* Position after the first term. */
-  assert( 1+n+nTerm<nData );
-  pReader->pData = pData+1+n+nTerm;
-  pReader->nData = nData-1-n-nTerm;
-}
-
-/* Step the reader forward to the next term. */
-static void leafReaderStep(LeafReader *pReader){
-  int n, nData, nPrefix, nSuffix;
-  assert( !leafReaderAtEnd(pReader) );
-
-  /* Skip previous entry's data block. */
-  n = fts3GetVarint32(pReader->pData, &nData);
-  assert( n+nData<=pReader->nData );
-  pReader->pData += n+nData;
-  pReader->nData -= n+nData;
-
-  if( !leafReaderAtEnd(pReader) ){
-    /* Construct the new term using a prefix from the old term plus a
-    ** suffix from the leaf data.
-    */
-    n = fts3GetVarint32(pReader->pData, &nPrefix);
-    n += fts3GetVarint32(pReader->pData+n, &nSuffix);
-    assert( n+nSuffix<pReader->nData );
-    pReader->term.nData = nPrefix;
-    dataBufferAppend(&pReader->term, pReader->pData+n, nSuffix);
-
-    pReader->pData += n+nSuffix;
-    pReader->nData -= n+nSuffix;
-  }
-}
-
-/* strcmp-style comparison of pReader's current term against pTerm.
-** If isPrefix, equality means equal through nTerm bytes.
-*/
-static int leafReaderTermCmp(LeafReader *pReader,
-                             const char *pTerm, int nTerm, int isPrefix){
-  int c, n = pReader->term.nData<nTerm ? pReader->term.nData : nTerm;
-  if( n==0 ){
-    if( pReader->term.nData>0 ) return -1;
-    if(nTerm>0 ) return 1;
-    return 0;
-  }
-
-  c = memcmp(pReader->term.pData, pTerm, n);
-  if( c!=0 ) return c;
-  if( isPrefix && n==nTerm ) return 0;
-  return pReader->term.nData - nTerm;
-}
-
-
-/****************************************************************/
-/* LeavesReader wraps LeafReader to allow iterating over the entire
-** leaf layer of the tree.
-*/
-typedef struct LeavesReader {
-  int idx;                  /* Index within the segment. */
-
-  sqlite3_stmt *pStmt;      /* Statement we're streaming leaves from. */
-  int eof;                  /* we've seen SQLITE_DONE from pStmt. */
-
-  LeafReader leafReader;    /* reader for the current leaf. */
-  DataBuffer rootData;      /* root data for inline. */
-} LeavesReader;
-
-/* Access the current term. */
-static int leavesReaderTermBytes(LeavesReader *pReader){
-  assert( !pReader->eof );
-  return leafReaderTermBytes(&pReader->leafReader);
-}
-static const char *leavesReaderTerm(LeavesReader *pReader){
-  assert( !pReader->eof );
-  return leafReaderTerm(&pReader->leafReader);
-}
-
-/* Access the doclist data for the current term. */
-static int leavesReaderDataBytes(LeavesReader *pReader){
-  assert( !pReader->eof );
-  return leafReaderDataBytes(&pReader->leafReader);
-}
-static const char *leavesReaderData(LeavesReader *pReader){
-  assert( !pReader->eof );
-  return leafReaderData(&pReader->leafReader);
-}
-
-static int leavesReaderAtEnd(LeavesReader *pReader){
-  return pReader->eof;
-}
-
-/* loadSegmentLeaves() may not read all the way to SQLITE_DONE, thus
-** leaving the statement handle open, which locks the table.
-*/
-/* TODO(shess) This "solution" is not satisfactory.  Really, there
-** should be check-in function for all statement handles which
-** arranges to call sqlite3_reset().  This most likely will require
-** modification to control flow all over the place, though, so for now
-** just punt.
-**
-** Note the the current system assumes that segment merges will run to
-** completion, which is why this particular probably hasn't arisen in
-** this case.  Probably a brittle assumption.
-*/
-static int leavesReaderReset(LeavesReader *pReader){
-  return sqlite3_reset(pReader->pStmt);
-}
-
-static void leavesReaderDestroy(LeavesReader *pReader){
-  /* If idx is -1, that means we're using a non-cached statement
-  ** handle in the optimize() case, so we need to release it.
-  */
-  if( pReader->pStmt!=NULL && pReader->idx==-1 ){
-    sqlite3_finalize(pReader->pStmt);
-  }
-  leafReaderDestroy(&pReader->leafReader);
-  dataBufferDestroy(&pReader->rootData);
-  SCRAMBLE(pReader);
-}
-
-/* Initialize pReader with the given root data (if iStartBlockid==0
-** the leaf data was entirely contained in the root), or from the
-** stream of blocks between iStartBlockid and iEndBlockid, inclusive.
-*/
-static int leavesReaderInit(fulltext_vtab *v,
-                            int idx,
-                            sqlite_int64 iStartBlockid,
-                            sqlite_int64 iEndBlockid,
-                            const char *pRootData, int nRootData,
-                            LeavesReader *pReader){
-  CLEAR(pReader);
-  pReader->idx = idx;
-
-  dataBufferInit(&pReader->rootData, 0);
-  if( iStartBlockid==0 ){
-    /* Entire leaf level fit in root data. */
-    dataBufferReplace(&pReader->rootData, pRootData, nRootData);
-    leafReaderInit(pReader->rootData.pData, pReader->rootData.nData,
-                   &pReader->leafReader);
-  }else{
-    sqlite3_stmt *s;
-    int rc = sql_get_leaf_statement(v, idx, &s);
-    if( rc!=SQLITE_OK ) return rc;
-
-    rc = sqlite3_bind_int64(s, 1, iStartBlockid);
-    if( rc!=SQLITE_OK ) return rc;
-
-    rc = sqlite3_bind_int64(s, 2, iEndBlockid);
-    if( rc!=SQLITE_OK ) return rc;
-
-    rc = sqlite3_step(s);
-    if( rc==SQLITE_DONE ){
-      pReader->eof = 1;
-      return SQLITE_OK;
-    }
-    if( rc!=SQLITE_ROW ) return rc;
-
-    pReader->pStmt = s;
-    leafReaderInit(sqlite3_column_blob(pReader->pStmt, 0),
-                   sqlite3_column_bytes(pReader->pStmt, 0),
-                   &pReader->leafReader);
-  }
-  return SQLITE_OK;
-}
-
-/* Step the current leaf forward to the next term.  If we reach the
-** end of the current leaf, step forward to the next leaf block.
-*/
-static int leavesReaderStep(fulltext_vtab *v, LeavesReader *pReader){
-  assert( !leavesReaderAtEnd(pReader) );
-  leafReaderStep(&pReader->leafReader);
-
-  if( leafReaderAtEnd(&pReader->leafReader) ){
-    int rc;
-    if( pReader->rootData.pData ){
-      pReader->eof = 1;
-      return SQLITE_OK;
-    }
-    rc = sqlite3_step(pReader->pStmt);
-    if( rc!=SQLITE_ROW ){
-      pReader->eof = 1;
-      return rc==SQLITE_DONE ? SQLITE_OK : rc;
-    }
-    leafReaderDestroy(&pReader->leafReader);
-    leafReaderInit(sqlite3_column_blob(pReader->pStmt, 0),
-                   sqlite3_column_bytes(pReader->pStmt, 0),
-                   &pReader->leafReader);
-  }
-  return SQLITE_OK;
-}
-
-/* Order LeavesReaders by their term, ignoring idx.  Readers at eof
-** always sort to the end.
-*/
-static int leavesReaderTermCmp(LeavesReader *lr1, LeavesReader *lr2){
-  if( leavesReaderAtEnd(lr1) ){
-    if( leavesReaderAtEnd(lr2) ) return 0;
-    return 1;
-  }
-  if( leavesReaderAtEnd(lr2) ) return -1;
-
-  return leafReaderTermCmp(&lr1->leafReader,
-                           leavesReaderTerm(lr2), leavesReaderTermBytes(lr2),
-                           0);
-}
-
-/* Similar to leavesReaderTermCmp(), with additional ordering by idx
-** so that older segments sort before newer segments.
-*/
-static int leavesReaderCmp(LeavesReader *lr1, LeavesReader *lr2){
-  int c = leavesReaderTermCmp(lr1, lr2);
-  if( c!=0 ) return c;
-  return lr1->idx-lr2->idx;
-}
-
-/* Assume that pLr[1]..pLr[nLr] are sorted.  Bubble pLr[0] into its
-** sorted position.
-*/
-static void leavesReaderReorder(LeavesReader *pLr, int nLr){
-  while( nLr>1 && leavesReaderCmp(pLr, pLr+1)>0 ){
-    LeavesReader tmp = pLr[0];
-    pLr[0] = pLr[1];
-    pLr[1] = tmp;
-    nLr--;
-    pLr++;
-  }
-}
-
-/* Initializes pReaders with the segments from level iLevel, returning
-** the number of segments in *piReaders.  Leaves pReaders in sorted
-** order.
-*/
-static int leavesReadersInit(fulltext_vtab *v, int iLevel,
-                             LeavesReader *pReaders, int *piReaders){
-  sqlite3_stmt *s;
-  int i, rc = sql_get_statement(v, SEGDIR_SELECT_LEVEL_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int(s, 1, iLevel);
-  if( rc!=SQLITE_OK ) return rc;
-
-  i = 0;
-  while( (rc = sqlite3_step(s))==SQLITE_ROW ){
-    sqlite_int64 iStart = sqlite3_column_int64(s, 0);
-    sqlite_int64 iEnd = sqlite3_column_int64(s, 1);
-    const char *pRootData = sqlite3_column_blob(s, 2);
-    int nRootData = sqlite3_column_bytes(s, 2);
-
-    assert( i<MERGE_COUNT );
-    rc = leavesReaderInit(v, i, iStart, iEnd, pRootData, nRootData,
-                          &pReaders[i]);
-    if( rc!=SQLITE_OK ) break;
-
-    i++;
-  }
-  if( rc!=SQLITE_DONE ){
-    while( i-->0 ){
-      leavesReaderDestroy(&pReaders[i]);
-    }
-    return rc;
-  }
-
-  *piReaders = i;
-
-  /* Leave our results sorted by term, then age. */
-  while( i-- ){
-    leavesReaderReorder(pReaders+i, *piReaders-i);
-  }
-  return SQLITE_OK;
-}
-
-/* Merge doclists from pReaders[nReaders] into a single doclist, which
-** is written to pWriter.  Assumes pReaders is ordered oldest to
-** newest.
-*/
-/* TODO(shess) Consider putting this inline in segmentMerge(). */
-static int leavesReadersMerge(fulltext_vtab *v,
-                              LeavesReader *pReaders, int nReaders,
-                              LeafWriter *pWriter){
-  DLReader dlReaders[MERGE_COUNT];
-  const char *pTerm = leavesReaderTerm(pReaders);
-  int i, nTerm = leavesReaderTermBytes(pReaders);
-
-  assert( nReaders<=MERGE_COUNT );
-
-  for(i=0; i<nReaders; i++){
-    dlrInit(&dlReaders[i], DL_DEFAULT,
-            leavesReaderData(pReaders+i),
-            leavesReaderDataBytes(pReaders+i));
-  }
-
-  return leafWriterStepMerge(v, pWriter, pTerm, nTerm, dlReaders, nReaders);
-}
-
-/* Forward ref due to mutual recursion with segdirNextIndex(). */
-static int segmentMerge(fulltext_vtab *v, int iLevel);
-
-/* Put the next available index at iLevel into *pidx.  If iLevel
-** already has MERGE_COUNT segments, they are merged to a higher
-** level to make room.
-*/
-static int segdirNextIndex(fulltext_vtab *v, int iLevel, int *pidx){
-  int rc = segdir_max_index(v, iLevel, pidx);
-  if( rc==SQLITE_DONE ){              /* No segments at iLevel. */
-    *pidx = 0;
-  }else if( rc==SQLITE_ROW ){
-    if( *pidx==(MERGE_COUNT-1) ){
-      rc = segmentMerge(v, iLevel);
-      if( rc!=SQLITE_OK ) return rc;
-      *pidx = 0;
-    }else{
-      (*pidx)++;
-    }
-  }else{
-    return rc;
-  }
-  return SQLITE_OK;
-}
-
-/* Merge MERGE_COUNT segments at iLevel into a new segment at
-** iLevel+1.  If iLevel+1 is already full of segments, those will be
-** merged to make room.
-*/
-static int segmentMerge(fulltext_vtab *v, int iLevel){
-  LeafWriter writer;
-  LeavesReader lrs[MERGE_COUNT];
-  int i, rc, idx = 0;
-
-  /* Determine the next available segment index at the next level,
-  ** merging as necessary.
-  */
-  rc = segdirNextIndex(v, iLevel+1, &idx);
-  if( rc!=SQLITE_OK ) return rc;
-
-  /* TODO(shess) This assumes that we'll always see exactly
-  ** MERGE_COUNT segments to merge at a given level.  That will be
-  ** broken if we allow the developer to request preemptive or
-  ** deferred merging.
-  */
-  memset(&lrs, '\0', sizeof(lrs));
-  rc = leavesReadersInit(v, iLevel, lrs, &i);
-  if( rc!=SQLITE_OK ) return rc;
-  assert( i==MERGE_COUNT );
-
-  leafWriterInit(iLevel+1, idx, &writer);
-
-  /* Since leavesReaderReorder() pushes readers at eof to the end,
-  ** when the first reader is empty, all will be empty.
-  */
-  while( !leavesReaderAtEnd(lrs) ){
-    /* Figure out how many readers share their next term. */
-    for(i=1; i<MERGE_COUNT && !leavesReaderAtEnd(lrs+i); i++){
-      if( 0!=leavesReaderTermCmp(lrs, lrs+i) ) break;
-    }
-
-    rc = leavesReadersMerge(v, lrs, i, &writer);
-    if( rc!=SQLITE_OK ) goto err;
-
-    /* Step forward those that were merged. */
-    while( i-->0 ){
-      rc = leavesReaderStep(v, lrs+i);
-      if( rc!=SQLITE_OK ) goto err;
-
-      /* Reorder by term, then by age. */
-      leavesReaderReorder(lrs+i, MERGE_COUNT-i);
-    }
-  }
-
-  for(i=0; i<MERGE_COUNT; i++){
-    leavesReaderDestroy(&lrs[i]);
-  }
-
-  rc = leafWriterFinalize(v, &writer);
-  leafWriterDestroy(&writer);
-  if( rc!=SQLITE_OK ) return rc;
-
-  /* Delete the merged segment data. */
-  return segdir_delete(v, iLevel);
-
- err:
-  for(i=0; i<MERGE_COUNT; i++){
-    leavesReaderDestroy(&lrs[i]);
-  }
-  leafWriterDestroy(&writer);
-  return rc;
-}
-
-/* Accumulate the union of *acc and *pData into *acc. */
-static void docListAccumulateUnion(DataBuffer *acc,
-                                   const char *pData, int nData) {
-  DataBuffer tmp = *acc;
-  dataBufferInit(acc, tmp.nData+nData);
-  docListUnion(tmp.pData, tmp.nData, pData, nData, acc);
-  dataBufferDestroy(&tmp);
-}
-
-/* TODO(shess) It might be interesting to explore different merge
-** strategies, here.  For instance, since this is a sorted merge, we
-** could easily merge many doclists in parallel.  With some
-** comprehension of the storage format, we could merge all of the
-** doclists within a leaf node directly from the leaf node's storage.
-** It may be worthwhile to merge smaller doclists before larger
-** doclists, since they can be traversed more quickly - but the
-** results may have less overlap, making them more expensive in a
-** different way.
-*/
-
-/* Scan pReader for pTerm/nTerm, and merge the term's doclist over
-** *out (any doclists with duplicate docids overwrite those in *out).
-** Internal function for loadSegmentLeaf().
-*/
-static int loadSegmentLeavesInt(fulltext_vtab *v, LeavesReader *pReader,
-                                const char *pTerm, int nTerm, int isPrefix,
-                                DataBuffer *out){
-  /* doclist data is accumulated into pBuffers similar to how one does
-  ** increment in binary arithmetic.  If index 0 is empty, the data is
-  ** stored there.  If there is data there, it is merged and the
-  ** results carried into position 1, with further merge-and-carry
-  ** until an empty position is found.
-  */
-  DataBuffer *pBuffers = NULL;
-  int nBuffers = 0, nMaxBuffers = 0, rc;
-
-  assert( nTerm>0 );
-
-  for(rc=SQLITE_OK; rc==SQLITE_OK && !leavesReaderAtEnd(pReader);
-      rc=leavesReaderStep(v, pReader)){
-    /* TODO(shess) Really want leavesReaderTermCmp(), but that name is
-    ** already taken to compare the terms of two LeavesReaders.  Think
-    ** on a better name.  [Meanwhile, break encapsulation rather than
-    ** use a confusing name.]
-    */
-    int c = leafReaderTermCmp(&pReader->leafReader, pTerm, nTerm, isPrefix);
-    if( c>0 ) break;      /* Past any possible matches. */
-    if( c==0 ){
-      const char *pData = leavesReaderData(pReader);
-      int iBuffer, nData = leavesReaderDataBytes(pReader);
-
-      /* Find the first empty buffer. */
-      for(iBuffer=0; iBuffer<nBuffers; ++iBuffer){
-        if( 0==pBuffers[iBuffer].nData ) break;
-      }
-
-      /* Out of buffers, add an empty one. */
-      if( iBuffer==nBuffers ){
-        if( nBuffers==nMaxBuffers ){
-          DataBuffer *p;
-          nMaxBuffers += 20;
-
-          /* Manual realloc so we can handle NULL appropriately. */
-          p = sqlite3_malloc(nMaxBuffers*sizeof(*pBuffers));
-          if( p==NULL ){
-            rc = SQLITE_NOMEM;
-            break;
-          }
-
-          if( nBuffers>0 ){
-            assert(pBuffers!=NULL);
-            memcpy(p, pBuffers, nBuffers*sizeof(*pBuffers));
-            sqlite3_free(pBuffers);
-          }
-          pBuffers = p;
-        }
-        dataBufferInit(&(pBuffers[nBuffers]), 0);
-        nBuffers++;
-      }
-
-      /* At this point, must have an empty at iBuffer. */
-      assert(iBuffer<nBuffers && pBuffers[iBuffer].nData==0);
-
-      /* If empty was first buffer, no need for merge logic. */
-      if( iBuffer==0 ){
-        dataBufferReplace(&(pBuffers[0]), pData, nData);
-      }else{
-        /* pAcc is the empty buffer the merged data will end up in. */
-        DataBuffer *pAcc = &(pBuffers[iBuffer]);
-        DataBuffer *p = &(pBuffers[0]);
-
-        /* Handle position 0 specially to avoid need to prime pAcc
-        ** with pData/nData.
-        */
-        dataBufferSwap(p, pAcc);
-        docListAccumulateUnion(pAcc, pData, nData);
-
-        /* Accumulate remaining doclists into pAcc. */
-        for(++p; p<pAcc; ++p){
-          docListAccumulateUnion(pAcc, p->pData, p->nData);
-
-          /* dataBufferReset() could allow a large doclist to blow up
-          ** our memory requirements.
-          */
-          if( p->nCapacity<1024 ){
-            dataBufferReset(p);
-          }else{
-            dataBufferDestroy(p);
-            dataBufferInit(p, 0);
-          }
-        }
-      }
-    }
-  }
-
-  /* Union all the doclists together into *out. */
-  /* TODO(shess) What if *out is big?  Sigh. */
-  if( rc==SQLITE_OK && nBuffers>0 ){
-    int iBuffer;
-    for(iBuffer=0; iBuffer<nBuffers; ++iBuffer){
-      if( pBuffers[iBuffer].nData>0 ){
-        if( out->nData==0 ){
-          dataBufferSwap(out, &(pBuffers[iBuffer]));
-        }else{
-          docListAccumulateUnion(out, pBuffers[iBuffer].pData,
-                                 pBuffers[iBuffer].nData);
-        }
-      }
-    }
-  }
-
-  while( nBuffers-- ){
-    dataBufferDestroy(&(pBuffers[nBuffers]));
-  }
-  if( pBuffers!=NULL ) sqlite3_free(pBuffers);
-
-  return rc;
-}
-
-/* Call loadSegmentLeavesInt() with pData/nData as input. */
-static int loadSegmentLeaf(fulltext_vtab *v, const char *pData, int nData,
-                           const char *pTerm, int nTerm, int isPrefix,
-                           DataBuffer *out){
-  LeavesReader reader;
-  int rc;
-
-  assert( nData>1 );
-  assert( *pData=='\0' );
-  rc = leavesReaderInit(v, 0, 0, 0, pData, nData, &reader);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = loadSegmentLeavesInt(v, &reader, pTerm, nTerm, isPrefix, out);
-  leavesReaderReset(&reader);
-  leavesReaderDestroy(&reader);
-  return rc;
-}
-
-/* Call loadSegmentLeavesInt() with the leaf nodes from iStartLeaf to
-** iEndLeaf (inclusive) as input, and merge the resulting doclist into
-** out.
-*/
-static int loadSegmentLeaves(fulltext_vtab *v,
-                             sqlite_int64 iStartLeaf, sqlite_int64 iEndLeaf,
-                             const char *pTerm, int nTerm, int isPrefix,
-                             DataBuffer *out){
-  int rc;
-  LeavesReader reader;
-
-  assert( iStartLeaf<=iEndLeaf );
-  rc = leavesReaderInit(v, 0, iStartLeaf, iEndLeaf, NULL, 0, &reader);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = loadSegmentLeavesInt(v, &reader, pTerm, nTerm, isPrefix, out);
-  leavesReaderReset(&reader);
-  leavesReaderDestroy(&reader);
-  return rc;
-}
-
-/* Taking pData/nData as an interior node, find the sequence of child
-** nodes which could include pTerm/nTerm/isPrefix.  Note that the
-** interior node terms logically come between the blocks, so there is
-** one more blockid than there are terms (that block contains terms >=
-** the last interior-node term).
-*/
-/* TODO(shess) The calling code may already know that the end child is
-** not worth calculating, because the end may be in a later sibling
-** node.  Consider whether breaking symmetry is worthwhile.  I suspect
-** it is not worthwhile.
-*/
-static void getChildrenContaining(const char *pData, int nData,
-                                  const char *pTerm, int nTerm, int isPrefix,
-                                  sqlite_int64 *piStartChild,
-                                  sqlite_int64 *piEndChild){
-  InteriorReader reader;
-
-  assert( nData>1 );
-  assert( *pData!='\0' );
-  interiorReaderInit(pData, nData, &reader);
-
-  /* Scan for the first child which could contain pTerm/nTerm. */
-  while( !interiorReaderAtEnd(&reader) ){
-    if( interiorReaderTermCmp(&reader, pTerm, nTerm, 0)>0 ) break;
-    interiorReaderStep(&reader);
-  }
-  *piStartChild = interiorReaderCurrentBlockid(&reader);
-
-  /* Keep scanning to find a term greater than our term, using prefix
-  ** comparison if indicated.  If isPrefix is false, this will be the
-  ** same blockid as the starting block.
-  */
-  while( !interiorReaderAtEnd(&reader) ){
-    if( interiorReaderTermCmp(&reader, pTerm, nTerm, isPrefix)>0 ) break;
-    interiorReaderStep(&reader);
-  }
-  *piEndChild = interiorReaderCurrentBlockid(&reader);
-
-  interiorReaderDestroy(&reader);
-
-  /* Children must ascend, and if !prefix, both must be the same. */
-  assert( *piEndChild>=*piStartChild );
-  assert( isPrefix || *piStartChild==*piEndChild );
-}
-
-/* Read block at iBlockid and pass it with other params to
-** getChildrenContaining().
-*/
-static int loadAndGetChildrenContaining(
-  fulltext_vtab *v,
-  sqlite_int64 iBlockid,
-  const char *pTerm, int nTerm, int isPrefix,
-  sqlite_int64 *piStartChild, sqlite_int64 *piEndChild
-){
-  sqlite3_stmt *s = NULL;
-  int rc;
-
-  assert( iBlockid!=0 );
-  assert( pTerm!=NULL );
-  assert( nTerm!=0 );        /* TODO(shess) Why not allow this? */
-  assert( piStartChild!=NULL );
-  assert( piEndChild!=NULL );
-
-  rc = sql_get_statement(v, BLOCK_SELECT_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int64(s, 1, iBlockid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_step(s);
-  if( rc==SQLITE_DONE ) return SQLITE_ERROR;
-  if( rc!=SQLITE_ROW ) return rc;
-
-  getChildrenContaining(sqlite3_column_blob(s, 0), sqlite3_column_bytes(s, 0),
-                        pTerm, nTerm, isPrefix, piStartChild, piEndChild);
-
-  /* We expect only one row.  We must execute another sqlite3_step()
-   * to complete the iteration; otherwise the table will remain
-   * locked. */
-  rc = sqlite3_step(s);
-  if( rc==SQLITE_ROW ) return SQLITE_ERROR;
-  if( rc!=SQLITE_DONE ) return rc;
-
-  return SQLITE_OK;
-}
-
-/* Traverse the tree represented by pData[nData] looking for
-** pTerm[nTerm], placing its doclist into *out.  This is internal to
-** loadSegment() to make error-handling cleaner.
-*/
-static int loadSegmentInt(fulltext_vtab *v, const char *pData, int nData,
-                          sqlite_int64 iLeavesEnd,
-                          const char *pTerm, int nTerm, int isPrefix,
-                          DataBuffer *out){
-  /* Special case where root is a leaf. */
-  if( *pData=='\0' ){
-    return loadSegmentLeaf(v, pData, nData, pTerm, nTerm, isPrefix, out);
-  }else{
-    int rc;
-    sqlite_int64 iStartChild, iEndChild;
-
-    /* Process pData as an interior node, then loop down the tree
-    ** until we find the set of leaf nodes to scan for the term.
-    */
-    getChildrenContaining(pData, nData, pTerm, nTerm, isPrefix,
-                          &iStartChild, &iEndChild);
-    while( iStartChild>iLeavesEnd ){
-      sqlite_int64 iNextStart, iNextEnd;
-      rc = loadAndGetChildrenContaining(v, iStartChild, pTerm, nTerm, isPrefix,
-                                        &iNextStart, &iNextEnd);
-      if( rc!=SQLITE_OK ) return rc;
-
-      /* If we've branched, follow the end branch, too. */
-      if( iStartChild!=iEndChild ){
-        sqlite_int64 iDummy;
-        rc = loadAndGetChildrenContaining(v, iEndChild, pTerm, nTerm, isPrefix,
-                                          &iDummy, &iNextEnd);
-        if( rc!=SQLITE_OK ) return rc;
-      }
-
-      assert( iNextStart<=iNextEnd );
-      iStartChild = iNextStart;
-      iEndChild = iNextEnd;
-    }
-    assert( iStartChild<=iLeavesEnd );
-    assert( iEndChild<=iLeavesEnd );
-
-    /* Scan through the leaf segments for doclists. */
-    return loadSegmentLeaves(v, iStartChild, iEndChild,
-                             pTerm, nTerm, isPrefix, out);
-  }
-}
-
-/* Call loadSegmentInt() to collect the doclist for pTerm/nTerm, then
-** merge its doclist over *out (any duplicate doclists read from the
-** segment rooted at pData will overwrite those in *out).
-*/
-/* TODO(shess) Consider changing this to determine the depth of the
-** leaves using either the first characters of interior nodes (when
-** ==1, we're one level above the leaves), or the first character of
-** the root (which will describe the height of the tree directly).
-** Either feels somewhat tricky to me.
-*/
-/* TODO(shess) The current merge is likely to be slow for large
-** doclists (though it should process from newest/smallest to
-** oldest/largest, so it may not be that bad).  It might be useful to
-** modify things to allow for N-way merging.  This could either be
-** within a segment, with pairwise merges across segments, or across
-** all segments at once.
-*/
-static int loadSegment(fulltext_vtab *v, const char *pData, int nData,
-                       sqlite_int64 iLeavesEnd,
-                       const char *pTerm, int nTerm, int isPrefix,
-                       DataBuffer *out){
-  DataBuffer result;
-  int rc;
-
-  assert( nData>1 );
-
-  /* This code should never be called with buffered updates. */
-  assert( v->nPendingData<0 );
-
-  dataBufferInit(&result, 0);
-  rc = loadSegmentInt(v, pData, nData, iLeavesEnd,
-                      pTerm, nTerm, isPrefix, &result);
-  if( rc==SQLITE_OK && result.nData>0 ){
-    if( out->nData==0 ){
-      DataBuffer tmp = *out;
-      *out = result;
-      result = tmp;
-    }else{
-      DataBuffer merged;
-      DLReader readers[2];
-
-      dlrInit(&readers[0], DL_DEFAULT, out->pData, out->nData);
-      dlrInit(&readers[1], DL_DEFAULT, result.pData, result.nData);
-      dataBufferInit(&merged, out->nData+result.nData);
-      docListMerge(&merged, readers, 2);
-      dataBufferDestroy(out);
-      *out = merged;
-      dlrDestroy(&readers[0]);
-      dlrDestroy(&readers[1]);
-    }
-  }
-  dataBufferDestroy(&result);
-  return rc;
-}
-
-/* Scan the database and merge together the posting lists for the term
-** into *out.
-*/
-static int termSelect(
-  fulltext_vtab *v,
-  int iColumn,
-  const char *pTerm, int nTerm,             /* Term to query for */
-  int isPrefix,                             /* True for a prefix search */
-  DocListType iType,
-  DataBuffer *out                           /* Write results here */
-){
-  DataBuffer doclist;
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, SEGDIR_SELECT_ALL_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  /* This code should never be called with buffered updates. */
-  assert( v->nPendingData<0 );
-
-  dataBufferInit(&doclist, 0);
-  dataBufferInit(out, 0);
-
-  /* Traverse the segments from oldest to newest so that newer doclist
-  ** elements for given docids overwrite older elements.
-  */
-  while( (rc = sqlite3_step(s))==SQLITE_ROW ){
-    const char *pData = sqlite3_column_blob(s, 2);
-    const int nData = sqlite3_column_bytes(s, 2);
-    const sqlite_int64 iLeavesEnd = sqlite3_column_int64(s, 1);
-    rc = loadSegment(v, pData, nData, iLeavesEnd, pTerm, nTerm, isPrefix,
-                     &doclist);
-    if( rc!=SQLITE_OK ) goto err;
-  }
-  if( rc==SQLITE_DONE ){
-    if( doclist.nData!=0 ){
-      /* TODO(shess) The old term_select_all() code applied the column
-      ** restrict as we merged segments, leading to smaller buffers.
-      ** This is probably worthwhile to bring back, once the new storage
-      ** system is checked in.
-      */
-      if( iColumn==v->nColumn) iColumn = -1;
-      docListTrim(DL_DEFAULT, doclist.pData, doclist.nData,
-                  iColumn, iType, out);
-    }
-    rc = SQLITE_OK;
-  }
-
- err:
-  dataBufferDestroy(&doclist);
-  return rc;
-}
-
-/****************************************************************/
-/* Used to hold hashtable data for sorting. */
-typedef struct TermData {
-  const char *pTerm;
-  int nTerm;
-  DLCollector *pCollector;
-} TermData;
-
-/* Orders TermData elements in strcmp fashion ( <0 for less-than, 0
-** for equal, >0 for greater-than).
-*/
-static int termDataCmp(const void *av, const void *bv){
-  const TermData *a = (const TermData *)av;
-  const TermData *b = (const TermData *)bv;
-  int n = a->nTerm<b->nTerm ? a->nTerm : b->nTerm;
-  int c = memcmp(a->pTerm, b->pTerm, n);
-  if( c!=0 ) return c;
-  return a->nTerm-b->nTerm;
-}
-
-/* Order pTerms data by term, then write a new level 0 segment using
-** LeafWriter.
-*/
-static int writeZeroSegment(fulltext_vtab *v, fts3Hash *pTerms){
-  fts3HashElem *e;
-  int idx, rc, i, n;
-  TermData *pData;
-  LeafWriter writer;
-  DataBuffer dl;
-
-  /* Determine the next index at level 0, merging as necessary. */
-  rc = segdirNextIndex(v, 0, &idx);
-  if( rc!=SQLITE_OK ) return rc;
-
-  n = fts3HashCount(pTerms);
-  pData = sqlite3_malloc(n*sizeof(TermData));
-
-  for(i = 0, e = fts3HashFirst(pTerms); e; i++, e = fts3HashNext(e)){
-    assert( i<n );
-    pData[i].pTerm = fts3HashKey(e);
-    pData[i].nTerm = fts3HashKeysize(e);
-    pData[i].pCollector = fts3HashData(e);
-  }
-  assert( i==n );
-
-  /* TODO(shess) Should we allow user-defined collation sequences,
-  ** here?  I think we only need that once we support prefix searches.
-  */
-  if( n>1 ) qsort(pData, n, sizeof(*pData), termDataCmp);
-
-  /* TODO(shess) Refactor so that we can write directly to the segment
-  ** DataBuffer, as happens for segment merges.
-  */
-  leafWriterInit(0, idx, &writer);
-  dataBufferInit(&dl, 0);
-  for(i=0; i<n; i++){
-    dataBufferReset(&dl);
-    dlcAddDoclist(pData[i].pCollector, &dl);
-    rc = leafWriterStep(v, &writer,
-                        pData[i].pTerm, pData[i].nTerm, dl.pData, dl.nData);
-    if( rc!=SQLITE_OK ) goto err;
-  }
-  rc = leafWriterFinalize(v, &writer);
-
- err:
-  dataBufferDestroy(&dl);
-  sqlite3_free(pData);
-  leafWriterDestroy(&writer);
-  return rc;
-}
-
-/* If pendingTerms has data, free it. */
-static int clearPendingTerms(fulltext_vtab *v){
-  if( v->nPendingData>=0 ){
-    fts3HashElem *e;
-    for(e=fts3HashFirst(&v->pendingTerms); e; e=fts3HashNext(e)){
-      dlcDelete(fts3HashData(e));
-    }
-    fts3HashClear(&v->pendingTerms);
-    v->nPendingData = -1;
-  }
-  return SQLITE_OK;
-}
-
-/* If pendingTerms has data, flush it to a level-zero segment, and
-** free it.
-*/
-static int flushPendingTerms(fulltext_vtab *v){
-  if( v->nPendingData>=0 ){
-    int rc = writeZeroSegment(v, &v->pendingTerms);
-    if( rc==SQLITE_OK ) clearPendingTerms(v);
-    return rc;
-  }
-  return SQLITE_OK;
-}
-
-/* If pendingTerms is "too big", or docid is out of order, flush it.
-** Regardless, be certain that pendingTerms is initialized for use.
-*/
-static int initPendingTerms(fulltext_vtab *v, sqlite_int64 iDocid){
-  /* TODO(shess) Explore whether partially flushing the buffer on
-  ** forced-flush would provide better performance.  I suspect that if
-  ** we ordered the doclists by size and flushed the largest until the
-  ** buffer was half empty, that would let the less frequent terms
-  ** generate longer doclists.
-  */
-  if( iDocid<=v->iPrevDocid || v->nPendingData>kPendingThreshold ){
-    int rc = flushPendingTerms(v);
-    if( rc!=SQLITE_OK ) return rc;
-  }
-  if( v->nPendingData<0 ){
-    fts3HashInit(&v->pendingTerms, FTS3_HASH_STRING, 1);
-    v->nPendingData = 0;
-  }
-  v->iPrevDocid = iDocid;
-  return SQLITE_OK;
-}
-
-/* This function implements the xUpdate callback; it is the top-level entry
- * point for inserting, deleting or updating a row in a full-text table. */
-static int fulltextUpdate(sqlite3_vtab *pVtab, int nArg, sqlite3_value **ppArg,
-                          sqlite_int64 *pRowid){
-  fulltext_vtab *v = (fulltext_vtab *) pVtab;
-  int rc;
-
-  FTSTRACE(("FTS3 Update %p\n", pVtab));
-
-  if( nArg<2 ){
-    rc = index_delete(v, sqlite3_value_int64(ppArg[0]));
-    if( rc==SQLITE_OK ){
-      /* If we just deleted the last row in the table, clear out the
-      ** index data.
-      */
-      rc = content_exists(v);
-      if( rc==SQLITE_ROW ){
-        rc = SQLITE_OK;
-      }else if( rc==SQLITE_DONE ){
-        /* Clear the pending terms so we don't flush a useless level-0
-        ** segment when the transaction closes.
-        */
-        rc = clearPendingTerms(v);
-        if( rc==SQLITE_OK ){
-          rc = segdir_delete_all(v);
-        }
-      }
-    }
-  } else if( sqlite3_value_type(ppArg[0]) != SQLITE_NULL ){
-    /* An update:
-     * ppArg[0] = old rowid
-     * ppArg[1] = new rowid
-     * ppArg[2..2+v->nColumn-1] = values
-     * ppArg[2+v->nColumn] = value for magic column (we ignore this)
-     * ppArg[2+v->nColumn+1] = value for docid
-     */
-    sqlite_int64 rowid = sqlite3_value_int64(ppArg[0]);
-    if( sqlite3_value_type(ppArg[1]) != SQLITE_INTEGER ||
-        sqlite3_value_int64(ppArg[1]) != rowid ){
-      rc = SQLITE_ERROR;  /* we don't allow changing the rowid */
-    }else if( sqlite3_value_type(ppArg[2+v->nColumn+1]) != SQLITE_INTEGER ||
-              sqlite3_value_int64(ppArg[2+v->nColumn+1]) != rowid ){
-      rc = SQLITE_ERROR;  /* we don't allow changing the docid */
-    }else{
-      assert( nArg==2+v->nColumn+2);
-      rc = index_update(v, rowid, &ppArg[2]);
-    }
-  } else {
-    /* An insert:
-     * ppArg[1] = requested rowid
-     * ppArg[2..2+v->nColumn-1] = values
-     * ppArg[2+v->nColumn] = value for magic column (we ignore this)
-     * ppArg[2+v->nColumn+1] = value for docid
-     */
-    sqlite3_value *pRequestDocid = ppArg[2+v->nColumn+1];
-    assert( nArg==2+v->nColumn+2);
-    if( SQLITE_NULL != sqlite3_value_type(pRequestDocid) &&
-        SQLITE_NULL != sqlite3_value_type(ppArg[1]) ){
-      /* TODO(shess) Consider allowing this to work if the values are
-      ** identical.  I'm inclined to discourage that usage, though,
-      ** given that both rowid and docid are special columns.  Better
-      ** would be to define one or the other as the default winner,
-      ** but should it be fts3-centric (docid) or SQLite-centric
-      ** (rowid)?
-      */
-      rc = SQLITE_ERROR;
-    }else{
-      if( SQLITE_NULL == sqlite3_value_type(pRequestDocid) ){
-        pRequestDocid = ppArg[1];
-      }
-      rc = index_insert(v, pRequestDocid, &ppArg[2], pRowid);
-    }
-  }
-
-  return rc;
-}
-
-static int fulltextSync(sqlite3_vtab *pVtab){
-  FTSTRACE(("FTS3 xSync()\n"));
-  return flushPendingTerms((fulltext_vtab *)pVtab);
-}
-
-static int fulltextBegin(sqlite3_vtab *pVtab){
-  fulltext_vtab *v = (fulltext_vtab *) pVtab;
-  FTSTRACE(("FTS3 xBegin()\n"));
-
-  /* Any buffered updates should have been cleared by the previous
-  ** transaction.
-  */
-  assert( v->nPendingData<0 );
-  return clearPendingTerms(v);
-}
-
-static int fulltextCommit(sqlite3_vtab *pVtab){
-  fulltext_vtab *v = (fulltext_vtab *) pVtab;
-  FTSTRACE(("FTS3 xCommit()\n"));
-
-  /* Buffered updates should have been cleared by fulltextSync(). */
-  assert( v->nPendingData<0 );
-  return clearPendingTerms(v);
-}
-
-static int fulltextRollback(sqlite3_vtab *pVtab){
-  FTSTRACE(("FTS3 xRollback()\n"));
-  return clearPendingTerms((fulltext_vtab *)pVtab);
-}
-
-/*
-** Implementation of the snippet() function for FTS3
-*/
-static void snippetFunc(
-  sqlite3_context *pContext,
-  int argc,
-  sqlite3_value **argv
-){
-  fulltext_cursor *pCursor;
-  if( argc<1 ) return;
-  if( sqlite3_value_type(argv[0])!=SQLITE_BLOB ||
-      sqlite3_value_bytes(argv[0])!=sizeof(pCursor) ){
-    sqlite3_result_error(pContext, "illegal first argument to html_snippet",-1);
-  }else{
-    const char *zStart = "<b>";
-    const char *zEnd = "</b>";
-    const char *zEllipsis = "<b>...</b>";
-    memcpy(&pCursor, sqlite3_value_blob(argv[0]), sizeof(pCursor));
-    if( argc>=2 ){
-      zStart = (const char*)sqlite3_value_text(argv[1]);
-      if( argc>=3 ){
-        zEnd = (const char*)sqlite3_value_text(argv[2]);
-        if( argc>=4 ){
-          zEllipsis = (const char*)sqlite3_value_text(argv[3]);
-        }
-      }
-    }
-    snippetAllOffsets(pCursor);
-    snippetText(pCursor, zStart, zEnd, zEllipsis);
-    sqlite3_result_text(pContext, pCursor->snippet.zSnippet,
-                        pCursor->snippet.nSnippet, SQLITE_STATIC);
-  }
-}
-
-/*
-** Implementation of the offsets() function for FTS3
-*/
-static void snippetOffsetsFunc(
-  sqlite3_context *pContext,
-  int argc,
-  sqlite3_value **argv
-){
-  fulltext_cursor *pCursor;
-  if( argc<1 ) return;
-  if( sqlite3_value_type(argv[0])!=SQLITE_BLOB ||
-      sqlite3_value_bytes(argv[0])!=sizeof(pCursor) ){
-    sqlite3_result_error(pContext, "illegal first argument to offsets",-1);
-  }else{
-    memcpy(&pCursor, sqlite3_value_blob(argv[0]), sizeof(pCursor));
-    snippetAllOffsets(pCursor);
-    snippetOffsetText(&pCursor->snippet);
-    sqlite3_result_text(pContext,
-                        pCursor->snippet.zOffset, pCursor->snippet.nOffset,
-                        SQLITE_STATIC);
-  }
-}
-
-/* OptLeavesReader is nearly identical to LeavesReader, except that
-** where LeavesReader is geared towards the merging of complete
-** segment levels (with exactly MERGE_COUNT segments), OptLeavesReader
-** is geared towards implementation of the optimize() function, and
-** can merge all segments simultaneously.  This version may be
-** somewhat less efficient than LeavesReader because it merges into an
-** accumulator rather than doing an N-way merge, but since segment
-** size grows exponentially (so segment count logrithmically) this is
-** probably not an immediate problem.
-*/
-/* TODO(shess): Prove that assertion, or extend the merge code to
-** merge tree fashion (like the prefix-searching code does).
-*/
-/* TODO(shess): OptLeavesReader and LeavesReader could probably be
-** merged with little or no loss of performance for LeavesReader.  The
-** merged code would need to handle >MERGE_COUNT segments, and would
-** also need to be able to optionally optimize away deletes.
-*/
-typedef struct OptLeavesReader {
-  /* Segment number, to order readers by age. */
-  int segment;
-  LeavesReader reader;
-} OptLeavesReader;
-
-static int optLeavesReaderAtEnd(OptLeavesReader *pReader){
-  return leavesReaderAtEnd(&pReader->reader);
-}
-static int optLeavesReaderTermBytes(OptLeavesReader *pReader){
-  return leavesReaderTermBytes(&pReader->reader);
-}
-static const char *optLeavesReaderData(OptLeavesReader *pReader){
-  return leavesReaderData(&pReader->reader);
-}
-static int optLeavesReaderDataBytes(OptLeavesReader *pReader){
-  return leavesReaderDataBytes(&pReader->reader);
-}
-static const char *optLeavesReaderTerm(OptLeavesReader *pReader){
-  return leavesReaderTerm(&pReader->reader);
-}
-static int optLeavesReaderStep(fulltext_vtab *v, OptLeavesReader *pReader){
-  return leavesReaderStep(v, &pReader->reader);
-}
-static int optLeavesReaderTermCmp(OptLeavesReader *lr1, OptLeavesReader *lr2){
-  return leavesReaderTermCmp(&lr1->reader, &lr2->reader);
-}
-/* Order by term ascending, segment ascending (oldest to newest), with
-** exhausted readers to the end.
-*/
-static int optLeavesReaderCmp(OptLeavesReader *lr1, OptLeavesReader *lr2){
-  int c = optLeavesReaderTermCmp(lr1, lr2);
-  if( c!=0 ) return c;
-  return lr1->segment-lr2->segment;
-}
-/* Bubble pLr[0] to appropriate place in pLr[1..nLr-1].  Assumes that
-** pLr[1..nLr-1] is already sorted.
-*/
-static void optLeavesReaderReorder(OptLeavesReader *pLr, int nLr){
-  while( nLr>1 && optLeavesReaderCmp(pLr, pLr+1)>0 ){
-    OptLeavesReader tmp = pLr[0];
-    pLr[0] = pLr[1];
-    pLr[1] = tmp;
-    nLr--;
-    pLr++;
-  }
-}
-
-/* optimize() helper function.  Put the readers in order and iterate
-** through them, merging doclists for matching terms into pWriter.
-** Returns SQLITE_OK on success, or the SQLite error code which
-** prevented success.
-*/
-static int optimizeInternal(fulltext_vtab *v,
-                            OptLeavesReader *readers, int nReaders,
-                            LeafWriter *pWriter){
-  int i, rc = SQLITE_OK;
-  DataBuffer doclist, merged, tmp;
-
-  /* Order the readers. */
-  i = nReaders;
-  while( i-- > 0 ){
-    optLeavesReaderReorder(&readers[i], nReaders-i);
-  }
-
-  dataBufferInit(&doclist, LEAF_MAX);
-  dataBufferInit(&merged, LEAF_MAX);
-
-  /* Exhausted readers bubble to the end, so when the first reader is
-  ** at eof, all are at eof.
-  */
-  while( !optLeavesReaderAtEnd(&readers[0]) ){
-
-    /* Figure out how many readers share the next term. */
-    for(i=1; i<nReaders && !optLeavesReaderAtEnd(&readers[i]); i++){
-      if( 0!=optLeavesReaderTermCmp(&readers[0], &readers[i]) ) break;
-    }
-
-    /* Special-case for no merge. */
-    if( i==1 ){
-      /* Trim deletions from the doclist. */
-      dataBufferReset(&merged);
-      docListTrim(DL_DEFAULT,
-                  optLeavesReaderData(&readers[0]),
-                  optLeavesReaderDataBytes(&readers[0]),
-                  -1, DL_DEFAULT, &merged);
-    }else{
-      DLReader dlReaders[MERGE_COUNT];
-      int iReader, nReaders;
-
-      /* Prime the pipeline with the first reader's doclist.  After
-      ** one pass index 0 will reference the accumulated doclist.
-      */
-      dlrInit(&dlReaders[0], DL_DEFAULT,
-              optLeavesReaderData(&readers[0]),
-              optLeavesReaderDataBytes(&readers[0]));
-      iReader = 1;
-
-      assert( iReader<i );  /* Must execute the loop at least once. */
-      while( iReader<i ){
-        /* Merge 16 inputs per pass. */
-        for( nReaders=1; iReader<i && nReaders<MERGE_COUNT;
-             iReader++, nReaders++ ){
-          dlrInit(&dlReaders[nReaders], DL_DEFAULT,
-                  optLeavesReaderData(&readers[iReader]),
-                  optLeavesReaderDataBytes(&readers[iReader]));
-        }
-
-        /* Merge doclists and swap result into accumulator. */
-        dataBufferReset(&merged);
-        docListMerge(&merged, dlReaders, nReaders);
-        tmp = merged;
-        merged = doclist;
-        doclist = tmp;
-
-        while( nReaders-- > 0 ){
-          dlrDestroy(&dlReaders[nReaders]);
-        }
-
-        /* Accumulated doclist to reader 0 for next pass. */
-        dlrInit(&dlReaders[0], DL_DEFAULT, doclist.pData, doclist.nData);
-      }
-
-      /* Destroy reader that was left in the pipeline. */
-      dlrDestroy(&dlReaders[0]);
-
-      /* Trim deletions from the doclist. */
-      dataBufferReset(&merged);
-      docListTrim(DL_DEFAULT, doclist.pData, doclist.nData,
-                  -1, DL_DEFAULT, &merged);
-    }
-
-    /* Only pass doclists with hits (skip if all hits deleted). */
-    if( merged.nData>0 ){
-      rc = leafWriterStep(v, pWriter,
-                          optLeavesReaderTerm(&readers[0]),
-                          optLeavesReaderTermBytes(&readers[0]),
-                          merged.pData, merged.nData);
-      if( rc!=SQLITE_OK ) goto err;
-    }
-
-    /* Step merged readers to next term and reorder. */
-    while( i-- > 0 ){
-      rc = optLeavesReaderStep(v, &readers[i]);
-      if( rc!=SQLITE_OK ) goto err;
-
-      optLeavesReaderReorder(&readers[i], nReaders-i);
-    }
-  }
-
- err:
-  dataBufferDestroy(&doclist);
-  dataBufferDestroy(&merged);
-  return rc;
-}
-
-/* Implement optimize() function for FTS3.  optimize(t) merges all
-** segments in the fts index into a single segment.  't' is the magic
-** table-named column.
-*/
-static void optimizeFunc(sqlite3_context *pContext,
-                         int argc, sqlite3_value **argv){
-  fulltext_cursor *pCursor;
-  if( argc>1 ){
-    sqlite3_result_error(pContext, "excess arguments to optimize()",-1);
-  }else if( sqlite3_value_type(argv[0])!=SQLITE_BLOB ||
-            sqlite3_value_bytes(argv[0])!=sizeof(pCursor) ){
-    sqlite3_result_error(pContext, "illegal first argument to optimize",-1);
-  }else{
-    fulltext_vtab *v;
-    int i, rc, iMaxLevel;
-    OptLeavesReader *readers;
-    int nReaders;
-    LeafWriter writer;
-    sqlite3_stmt *s;
-
-    memcpy(&pCursor, sqlite3_value_blob(argv[0]), sizeof(pCursor));
-    v = cursor_vtab(pCursor);
-
-    /* Flush any buffered updates before optimizing. */
-    rc = flushPendingTerms(v);
-    if( rc!=SQLITE_OK ) goto err;
-
-    rc = segdir_count(v, &nReaders, &iMaxLevel);
-    if( rc!=SQLITE_OK ) goto err;
-    if( nReaders==0 || nReaders==1 ){
-      sqlite3_result_text(pContext, "Index already optimal", -1,
-                          SQLITE_STATIC);
-      return;
-    }
-
-    rc = sql_get_statement(v, SEGDIR_SELECT_ALL_STMT, &s);
-    if( rc!=SQLITE_OK ) goto err;
-
-    readers = sqlite3_malloc(nReaders*sizeof(readers[0]));
-    if( readers==NULL ) goto err;
-
-    /* Note that there will already be a segment at this position
-    ** until we call segdir_delete() on iMaxLevel.
-    */
-    leafWriterInit(iMaxLevel, 0, &writer);
-
-    i = 0;
-    while( (rc = sqlite3_step(s))==SQLITE_ROW ){
-      sqlite_int64 iStart = sqlite3_column_int64(s, 0);
-      sqlite_int64 iEnd = sqlite3_column_int64(s, 1);
-      const char *pRootData = sqlite3_column_blob(s, 2);
-      int nRootData = sqlite3_column_bytes(s, 2);
-
-      assert( i<nReaders );
-      rc = leavesReaderInit(v, -1, iStart, iEnd, pRootData, nRootData,
-                            &readers[i].reader);
-      if( rc!=SQLITE_OK ) break;
-
-      readers[i].segment = i;
-      i++;
-    }
-
-    /* If we managed to successfully read them all, optimize them. */
-    if( rc==SQLITE_DONE ){
-      assert( i==nReaders );
-      rc = optimizeInternal(v, readers, nReaders, &writer);
-    }
-
-    while( i-- > 0 ){
-      leavesReaderDestroy(&readers[i].reader);
-    }
-    sqlite3_free(readers);
-
-    /* If we've successfully gotten to here, delete the old segments
-    ** and flush the interior structure of the new segment.
-    */
-    if( rc==SQLITE_OK ){
-      for( i=0; i<=iMaxLevel; i++ ){
-        rc = segdir_delete(v, i);
-        if( rc!=SQLITE_OK ) break;
-      }
-
-      if( rc==SQLITE_OK ) rc = leafWriterFinalize(v, &writer);
-    }
-
-    leafWriterDestroy(&writer);
-
-    if( rc!=SQLITE_OK ) goto err;
-
-    sqlite3_result_text(pContext, "Index optimized", -1, SQLITE_STATIC);
-    return;
-
-    /* TODO(shess): Error-handling needs to be improved along the
-    ** lines of the dump_ functions.
-    */
- err:
-    {
-      char buf[512];
-      sqlite3_snprintf(sizeof(buf), buf, "Error in optimize: %s",
-                       sqlite3_errmsg(sqlite3_context_db_handle(pContext)));
-      sqlite3_result_error(pContext, buf, -1);
-    }
-  }
-}
-
-#ifdef SQLITE_TEST
-/* Generate an error of the form "<prefix>: <msg>".  If msg is NULL,
-** pull the error from the context's db handle.
-*/
-static void generateError(sqlite3_context *pContext,
-                          const char *prefix, const char *msg){
-  char buf[512];
-  if( msg==NULL ) msg = sqlite3_errmsg(sqlite3_context_db_handle(pContext));
-  sqlite3_snprintf(sizeof(buf), buf, "%s: %s", prefix, msg);
-  sqlite3_result_error(pContext, buf, -1);
-}
-
-/* Helper function to collect the set of terms in the segment into
-** pTerms.  The segment is defined by the leaf nodes between
-** iStartBlockid and iEndBlockid, inclusive, or by the contents of
-** pRootData if iStartBlockid is 0 (in which case the entire segment
-** fit in a leaf).
-*/
-static int collectSegmentTerms(fulltext_vtab *v, sqlite3_stmt *s,
-                               fts3Hash *pTerms){
-  const sqlite_int64 iStartBlockid = sqlite3_column_int64(s, 0);
-  const sqlite_int64 iEndBlockid = sqlite3_column_int64(s, 1);
-  const char *pRootData = sqlite3_column_blob(s, 2);
-  const int nRootData = sqlite3_column_bytes(s, 2);
-  LeavesReader reader;
-  int rc = leavesReaderInit(v, 0, iStartBlockid, iEndBlockid,
-                            pRootData, nRootData, &reader);
-  if( rc!=SQLITE_OK ) return rc;
-
-  while( rc==SQLITE_OK && !leavesReaderAtEnd(&reader) ){
-    const char *pTerm = leavesReaderTerm(&reader);
-    const int nTerm = leavesReaderTermBytes(&reader);
-    void *oldValue = sqlite3Fts3HashFind(pTerms, pTerm, nTerm);
-    void *newValue = (void *)((char *)oldValue+1);
-
-    /* From the comment before sqlite3Fts3HashInsert in fts3_hash.c,
-    ** the data value passed is returned in case of malloc failure.
-    */
-    if( newValue==sqlite3Fts3HashInsert(pTerms, pTerm, nTerm, newValue) ){
-      rc = SQLITE_NOMEM;
-    }else{
-      rc = leavesReaderStep(v, &reader);
-    }
-  }
-
-  leavesReaderDestroy(&reader);
-  return rc;
-}
-
-/* Helper function to build the result string for dump_terms(). */
-static int generateTermsResult(sqlite3_context *pContext, fts3Hash *pTerms){
-  int iTerm, nTerms, nResultBytes, iByte;
-  char *result;
-  TermData *pData;
-  fts3HashElem *e;
-
-  /* Iterate pTerms to generate an array of terms in pData for
-  ** sorting.
-  */
-  nTerms = fts3HashCount(pTerms);
-  assert( nTerms>0 );
-  pData = sqlite3_malloc(nTerms*sizeof(TermData));
-  if( pData==NULL ) return SQLITE_NOMEM;
-
-  nResultBytes = 0;
-  for(iTerm = 0, e = fts3HashFirst(pTerms); e; iTerm++, e = fts3HashNext(e)){
-    nResultBytes += fts3HashKeysize(e)+1;   /* Term plus trailing space */
-    assert( iTerm<nTerms );
-    pData[iTerm].pTerm = fts3HashKey(e);
-    pData[iTerm].nTerm = fts3HashKeysize(e);
-    pData[iTerm].pCollector = fts3HashData(e);  /* unused */
-  }
-  assert( iTerm==nTerms );
-
-  assert( nResultBytes>0 );   /* nTerms>0, nResultsBytes must be, too. */
-  result = sqlite3_malloc(nResultBytes);
-  if( result==NULL ){
-    sqlite3_free(pData);
-    return SQLITE_NOMEM;
-  }
-
-  if( nTerms>1 ) qsort(pData, nTerms, sizeof(*pData), termDataCmp);
-
-  /* Read the terms in order to build the result. */
-  iByte = 0;
-  for(iTerm=0; iTerm<nTerms; ++iTerm){
-    memcpy(result+iByte, pData[iTerm].pTerm, pData[iTerm].nTerm);
-    iByte += pData[iTerm].nTerm;
-    result[iByte++] = ' ';
-  }
-  assert( iByte==nResultBytes );
-  assert( result[nResultBytes-1]==' ' );
-  result[nResultBytes-1] = '\0';
-
-  /* Passes away ownership of result. */
-  sqlite3_result_text(pContext, result, nResultBytes-1, sqlite3_free);
-  sqlite3_free(pData);
-  return SQLITE_OK;
-}
-
-/* Implements dump_terms() for use in inspecting the fts3 index from
-** tests.  TEXT result containing the ordered list of terms joined by
-** spaces.  dump_terms(t, level, idx) dumps the terms for the segment
-** specified by level, idx (in %_segdir), while dump_terms(t) dumps
-** all terms in the index.  In both cases t is the fts table's magic
-** table-named column.
-*/
-static void dumpTermsFunc(
-  sqlite3_context *pContext,
-  int argc, sqlite3_value **argv
-){
-  fulltext_cursor *pCursor;
-  if( argc!=3 && argc!=1 ){
-    generateError(pContext, "dump_terms", "incorrect arguments");
-  }else if( sqlite3_value_type(argv[0])!=SQLITE_BLOB ||
-            sqlite3_value_bytes(argv[0])!=sizeof(pCursor) ){
-    generateError(pContext, "dump_terms", "illegal first argument");
-  }else{
-    fulltext_vtab *v;
-    fts3Hash terms;
-    sqlite3_stmt *s = NULL;
-    int rc;
-
-    memcpy(&pCursor, sqlite3_value_blob(argv[0]), sizeof(pCursor));
-    v = cursor_vtab(pCursor);
-
-    /* If passed only the cursor column, get all segments.  Otherwise
-    ** get the segment described by the following two arguments.
-    */
-    if( argc==1 ){
-      rc = sql_get_statement(v, SEGDIR_SELECT_ALL_STMT, &s);
-    }else{
-      rc = sql_get_statement(v, SEGDIR_SELECT_SEGMENT_STMT, &s);
-      if( rc==SQLITE_OK ){
-        rc = sqlite3_bind_int(s, 1, sqlite3_value_int(argv[1]));
-        if( rc==SQLITE_OK ){
-          rc = sqlite3_bind_int(s, 2, sqlite3_value_int(argv[2]));
-        }
-      }
-    }
-
-    if( rc!=SQLITE_OK ){
-      generateError(pContext, "dump_terms", NULL);
-      return;
-    }
-
-    /* Collect the terms for each segment. */
-    sqlite3Fts3HashInit(&terms, FTS3_HASH_STRING, 1);
-    while( (rc = sqlite3_step(s))==SQLITE_ROW ){
-      rc = collectSegmentTerms(v, s, &terms);
-      if( rc!=SQLITE_OK ) break;
-    }
-
-    if( rc!=SQLITE_DONE ){
-      sqlite3_reset(s);
-      generateError(pContext, "dump_terms", NULL);
-    }else{
-      const int nTerms = fts3HashCount(&terms);
-      if( nTerms>0 ){
-        rc = generateTermsResult(pContext, &terms);
-        if( rc==SQLITE_NOMEM ){
-          generateError(pContext, "dump_terms", "out of memory");
-        }else{
-          assert( rc==SQLITE_OK );
-        }
-      }else if( argc==3 ){
-        /* The specific segment asked for could not be found. */
-        generateError(pContext, "dump_terms", "segment not found");
-      }else{
-        /* No segments found. */
-        /* TODO(shess): It should be impossible to reach this.  This
-        ** case can only happen for an empty table, in which case
-        ** SQLite has no rows to call this function on.
-        */
-        sqlite3_result_null(pContext);
-      }
-    }
-    sqlite3Fts3HashClear(&terms);
-  }
-}
-
-/* Expand the DL_DEFAULT doclist in pData into a text result in
-** pContext.
-*/
-static void createDoclistResult(sqlite3_context *pContext,
-                                const char *pData, int nData){
-  DataBuffer dump;
-  DLReader dlReader;
-
-  assert( pData!=NULL && nData>0 );
-
-  dataBufferInit(&dump, 0);
-  dlrInit(&dlReader, DL_DEFAULT, pData, nData);
-  for( ; !dlrAtEnd(&dlReader); dlrStep(&dlReader) ){
-    char buf[256];
-    PLReader plReader;
-
-    plrInit(&plReader, &dlReader);
-    if( DL_DEFAULT==DL_DOCIDS || plrAtEnd(&plReader) ){
-      sqlite3_snprintf(sizeof(buf), buf, "[%lld] ", dlrDocid(&dlReader));
-      dataBufferAppend(&dump, buf, strlen(buf));
-    }else{
-      int iColumn = plrColumn(&plReader);
-
-      sqlite3_snprintf(sizeof(buf), buf, "[%lld %d[",
-                       dlrDocid(&dlReader), iColumn);
-      dataBufferAppend(&dump, buf, strlen(buf));
-
-      for( ; !plrAtEnd(&plReader); plrStep(&plReader) ){
-        if( plrColumn(&plReader)!=iColumn ){
-          iColumn = plrColumn(&plReader);
-          sqlite3_snprintf(sizeof(buf), buf, "] %d[", iColumn);
-          assert( dump.nData>0 );
-          dump.nData--;                     /* Overwrite trailing space. */
-          assert( dump.pData[dump.nData]==' ');
-          dataBufferAppend(&dump, buf, strlen(buf));
-        }
-        if( DL_DEFAULT==DL_POSITIONS_OFFSETS ){
-          sqlite3_snprintf(sizeof(buf), buf, "%d,%d,%d ",
-                           plrPosition(&plReader),
-                           plrStartOffset(&plReader), plrEndOffset(&plReader));
-        }else if( DL_DEFAULT==DL_POSITIONS ){
-          sqlite3_snprintf(sizeof(buf), buf, "%d ", plrPosition(&plReader));
-        }else{
-          assert( NULL=="Unhandled DL_DEFAULT value");
-        }
-        dataBufferAppend(&dump, buf, strlen(buf));
-      }
-      plrDestroy(&plReader);
-
-      assert( dump.nData>0 );
-      dump.nData--;                     /* Overwrite trailing space. */
-      assert( dump.pData[dump.nData]==' ');
-      dataBufferAppend(&dump, "]] ", 3);
-    }
-  }
-  dlrDestroy(&dlReader);
-
-  assert( dump.nData>0 );
-  dump.nData--;                     /* Overwrite trailing space. */
-  assert( dump.pData[dump.nData]==' ');
-  dump.pData[dump.nData] = '\0';
-  assert( dump.nData>0 );
-
-  /* Passes ownership of dump's buffer to pContext. */
-  sqlite3_result_text(pContext, dump.pData, dump.nData, sqlite3_free);
-  dump.pData = NULL;
-  dump.nData = dump.nCapacity = 0;
-}
-
-/* Implements dump_doclist() for use in inspecting the fts3 index from
-** tests.  TEXT result containing a string representation of the
-** doclist for the indicated term.  dump_doclist(t, term, level, idx)
-** dumps the doclist for term from the segment specified by level, idx
-** (in %_segdir), while dump_doclist(t, term) dumps the logical
-** doclist for the term across all segments.  The per-segment doclist
-** can contain deletions, while the full-index doclist will not
-** (deletions are omitted).
-**
-** Result formats differ with the setting of DL_DEFAULTS.  Examples:
-**
-** DL_DOCIDS: [1] [3] [7]
-** DL_POSITIONS: [1 0[0 4] 1[17]] [3 1[5]]
-** DL_POSITIONS_OFFSETS: [1 0[0,0,3 4,23,26] 1[17,102,105]] [3 1[5,20,23]]
-**
-** In each case the number after the outer '[' is the docid.  In the
-** latter two cases, the number before the inner '[' is the column
-** associated with the values within.  For DL_POSITIONS the numbers
-** within are the positions, for DL_POSITIONS_OFFSETS they are the
-** position, the start offset, and the end offset.
-*/
-static void dumpDoclistFunc(
-  sqlite3_context *pContext,
-  int argc, sqlite3_value **argv
-){
-  fulltext_cursor *pCursor;
-  if( argc!=2 && argc!=4 ){
-    generateError(pContext, "dump_doclist", "incorrect arguments");
-  }else if( sqlite3_value_type(argv[0])!=SQLITE_BLOB ||
-            sqlite3_value_bytes(argv[0])!=sizeof(pCursor) ){
-    generateError(pContext, "dump_doclist", "illegal first argument");
-  }else if( sqlite3_value_text(argv[1])==NULL ||
-            sqlite3_value_text(argv[1])[0]=='\0' ){
-    generateError(pContext, "dump_doclist", "empty second argument");
-  }else{
-    const char *pTerm = (const char *)sqlite3_value_text(argv[1]);
-    const int nTerm = strlen(pTerm);
-    fulltext_vtab *v;
-    int rc;
-    DataBuffer doclist;
-
-    memcpy(&pCursor, sqlite3_value_blob(argv[0]), sizeof(pCursor));
-    v = cursor_vtab(pCursor);
-
-    dataBufferInit(&doclist, 0);
-
-    /* termSelect() yields the same logical doclist that queries are
-    ** run against.
-    */
-    if( argc==2 ){
-      rc = termSelect(v, v->nColumn, pTerm, nTerm, 0, DL_DEFAULT, &doclist);
-    }else{
-      sqlite3_stmt *s = NULL;
-
-      /* Get our specific segment's information. */
-      rc = sql_get_statement(v, SEGDIR_SELECT_SEGMENT_STMT, &s);
-      if( rc==SQLITE_OK ){
-        rc = sqlite3_bind_int(s, 1, sqlite3_value_int(argv[2]));
-        if( rc==SQLITE_OK ){
-          rc = sqlite3_bind_int(s, 2, sqlite3_value_int(argv[3]));
-        }
-      }
-
-      if( rc==SQLITE_OK ){
-        rc = sqlite3_step(s);
-
-        if( rc==SQLITE_DONE ){
-          dataBufferDestroy(&doclist);
-          generateError(pContext, "dump_doclist", "segment not found");
-          return;
-        }
-
-        /* Found a segment, load it into doclist. */
-        if( rc==SQLITE_ROW ){
-          const sqlite_int64 iLeavesEnd = sqlite3_column_int64(s, 1);
-          const char *pData = sqlite3_column_blob(s, 2);
-          const int nData = sqlite3_column_bytes(s, 2);
-
-          /* loadSegment() is used by termSelect() to load each
-          ** segment's data.
-          */
-          rc = loadSegment(v, pData, nData, iLeavesEnd, pTerm, nTerm, 0,
-                           &doclist);
-          if( rc==SQLITE_OK ){
-            rc = sqlite3_step(s);
-
-            /* Should not have more than one matching segment. */
-            if( rc!=SQLITE_DONE ){
-              sqlite3_reset(s);
-              dataBufferDestroy(&doclist);
-              generateError(pContext, "dump_doclist", "invalid segdir");
-              return;
-            }
-            rc = SQLITE_OK;
-          }
-        }
-      }
-
-      sqlite3_reset(s);
-    }
-
-    if( rc==SQLITE_OK ){
-      if( doclist.nData>0 ){
-        createDoclistResult(pContext, doclist.pData, doclist.nData);
-      }else{
-        /* TODO(shess): This can happen if the term is not present, or
-        ** if all instances of the term have been deleted and this is
-        ** an all-index dump.  It may be interesting to distinguish
-        ** these cases.
-        */
-        sqlite3_result_text(pContext, "", 0, SQLITE_STATIC);
-      }
-    }else if( rc==SQLITE_NOMEM ){
-      /* Handle out-of-memory cases specially because if they are
-      ** generated in fts3 code they may not be reflected in the db
-      ** handle.
-      */
-      /* TODO(shess): Handle this more comprehensively.
-      ** sqlite3ErrStr() has what I need, but is internal.
-      */
-      generateError(pContext, "dump_doclist", "out of memory");
-    }else{
-      generateError(pContext, "dump_doclist", NULL);
-    }
-
-    dataBufferDestroy(&doclist);
-  }
-}
-#endif
-
-/*
-** This routine implements the xFindFunction method for the FTS3
-** virtual table.
-*/
-static int fulltextFindFunction(
-  sqlite3_vtab *pVtab,
-  int nArg,
-  const char *zName,
-  void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
-  void **ppArg
-){
-  if( strcmp(zName,"snippet")==0 ){
-    *pxFunc = snippetFunc;
-    return 1;
-  }else if( strcmp(zName,"offsets")==0 ){
-    *pxFunc = snippetOffsetsFunc;
-    return 1;
-  }else if( strcmp(zName,"optimize")==0 ){
-    *pxFunc = optimizeFunc;
-    return 1;
-#ifdef SQLITE_TEST
-    /* NOTE(shess): These functions are present only for testing
-    ** purposes.  No particular effort is made to optimize their
-    ** execution or how they build their results.
-    */
-  }else if( strcmp(zName,"dump_terms")==0 ){
-    /* fprintf(stderr, "Found dump_terms\n"); */
-    *pxFunc = dumpTermsFunc;
-    return 1;
-  }else if( strcmp(zName,"dump_doclist")==0 ){
-    /* fprintf(stderr, "Found dump_doclist\n"); */
-    *pxFunc = dumpDoclistFunc;
-    return 1;
-#endif
-  }
-  return 0;
-}
-
-/*
-** Rename an fts3 table.
-*/
-static int fulltextRename(
-  sqlite3_vtab *pVtab,
-  const char *zName
-){
-  fulltext_vtab *p = (fulltext_vtab *)pVtab;
-  int rc = SQLITE_NOMEM;
-  char *zSql = sqlite3_mprintf(
-    "ALTER TABLE %Q.'%q_content'  RENAME TO '%q_content';"
-    "ALTER TABLE %Q.'%q_segments' RENAME TO '%q_segments';"
-    "ALTER TABLE %Q.'%q_segdir'   RENAME TO '%q_segdir';"
-    , p->zDb, p->zName, zName
-    , p->zDb, p->zName, zName
-    , p->zDb, p->zName, zName
-  );
-  if( zSql ){
-    rc = sqlite3_exec(p->db, zSql, 0, 0, 0);
-    sqlite3_free(zSql);
-  }
-  return rc;
-}
-
-static const sqlite3_module fts3Module = {
-  /* iVersion      */ 0,
-  /* xCreate       */ fulltextCreate,
-  /* xConnect      */ fulltextConnect,
-  /* xBestIndex    */ fulltextBestIndex,
-  /* xDisconnect   */ fulltextDisconnect,
-  /* xDestroy      */ fulltextDestroy,
-  /* xOpen         */ fulltextOpen,
-  /* xClose        */ fulltextClose,
-  /* xFilter       */ fulltextFilter,
-  /* xNext         */ fulltextNext,
-  /* xEof          */ fulltextEof,
-  /* xColumn       */ fulltextColumn,
-  /* xRowid        */ fulltextRowid,
-  /* xUpdate       */ fulltextUpdate,
-  /* xBegin        */ fulltextBegin,
-  /* xSync         */ fulltextSync,
-  /* xCommit       */ fulltextCommit,
-  /* xRollback     */ fulltextRollback,
-  /* xFindFunction */ fulltextFindFunction,
-  /* xRename */       fulltextRename,
-};
-
-static void hashDestroy(void *p){
-  fts3Hash *pHash = (fts3Hash *)p;
-  sqlite3Fts3HashClear(pHash);
-  sqlite3_free(pHash);
-}
-
-/*
-** The fts3 built-in tokenizers - "simple" and "porter" - are implemented
-** in files fts3_tokenizer1.c and fts3_porter.c respectively. The following
-** two forward declarations are for functions declared in these files
-** used to retrieve the respective implementations.
-**
-** Calling sqlite3Fts3SimpleTokenizerModule() sets the value pointed
-** to by the argument to point a the "simple" tokenizer implementation.
-** Function ...PorterTokenizerModule() sets *pModule to point to the
-** porter tokenizer/stemmer implementation.
-*/
-SQLITE_PRIVATE void sqlite3Fts3SimpleTokenizerModule(sqlite3_tokenizer_module const**ppModule);
-SQLITE_PRIVATE void sqlite3Fts3PorterTokenizerModule(sqlite3_tokenizer_module const**ppModule);
-SQLITE_PRIVATE void sqlite3Fts3IcuTokenizerModule(sqlite3_tokenizer_module const**ppModule);
-
-SQLITE_PRIVATE int sqlite3Fts3InitHashTable(sqlite3 *, fts3Hash *, const char *);
-
-/*
-** Initialise the fts3 extension. If this extension is built as part
-** of the sqlite library, then this function is called directly by
-** SQLite. If fts3 is built as a dynamically loadable extension, this
-** function is called by the sqlite3_extension_init() entry point.
-*/
-SQLITE_PRIVATE int sqlite3Fts3Init(sqlite3 *db){
-  int rc = SQLITE_OK;
-  fts3Hash *pHash = 0;
-  const sqlite3_tokenizer_module *pSimple = 0;
-  const sqlite3_tokenizer_module *pPorter = 0;
-  const sqlite3_tokenizer_module *pIcu = 0;
-
-  sqlite3Fts3SimpleTokenizerModule(&pSimple);
-  sqlite3Fts3PorterTokenizerModule(&pPorter);
-#ifdef SQLITE_ENABLE_ICU
-  sqlite3Fts3IcuTokenizerModule(&pIcu);
-#endif
-
-  /* Allocate and initialise the hash-table used to store tokenizers. */
-  pHash = sqlite3_malloc(sizeof(fts3Hash));
-  if( !pHash ){
-    rc = SQLITE_NOMEM;
-  }else{
-    sqlite3Fts3HashInit(pHash, FTS3_HASH_STRING, 1);
-  }
-
-  /* Load the built-in tokenizers into the hash table */
-  if( rc==SQLITE_OK ){
-    if( sqlite3Fts3HashInsert(pHash, "simple", 7, (void *)pSimple)
-     || sqlite3Fts3HashInsert(pHash, "porter", 7, (void *)pPorter)
-     || (pIcu && sqlite3Fts3HashInsert(pHash, "icu", 4, (void *)pIcu))
-    ){
-      rc = SQLITE_NOMEM;
-    }
-  }
-
-#ifdef SQLITE_TEST
-  sqlite3Fts3ExprInitTestInterface(db);
-#endif
-
-  /* Create the virtual table wrapper around the hash-table and overload
-  ** the two scalar functions. If this is successful, register the
-  ** module with sqlite.
-  */
-  if( SQLITE_OK==rc
-   && SQLITE_OK==(rc = sqlite3Fts3InitHashTable(db, pHash, "fts3_tokenizer"))
-   && SQLITE_OK==(rc = sqlite3_overload_function(db, "snippet", -1))
-   && SQLITE_OK==(rc = sqlite3_overload_function(db, "offsets", -1))
-   && SQLITE_OK==(rc = sqlite3_overload_function(db, "optimize", -1))
-#ifdef SQLITE_TEST
-   && SQLITE_OK==(rc = sqlite3_overload_function(db, "dump_terms", -1))
-   && SQLITE_OK==(rc = sqlite3_overload_function(db, "dump_doclist", -1))
-#endif
-  ){
-    return sqlite3_create_module_v2(
-        db, "fts3", &fts3Module, (void *)pHash, hashDestroy
-    );
-  }
-
-  /* An error has occurred. Delete the hash table and return the error code. */
-  assert( rc!=SQLITE_OK );
-  if( pHash ){
-    sqlite3Fts3HashClear(pHash);
-    sqlite3_free(pHash);
-  }
-  return rc;
-}
-
-#if !SQLITE_CORE
-SQLITE_API int sqlite3_extension_init(
-  sqlite3 *db,
-  char **pzErrMsg,
-  const sqlite3_api_routines *pApi
-){
-  SQLITE_EXTENSION_INIT2(pApi)
-  return sqlite3Fts3Init(db);
-}
-#endif
-
-#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
-
-/************** End of fts3.c ************************************************/
-/************** Begin file fts3_expr.c ***************************************/
-/*
-** 2008 Nov 28
-**
-** The author disclaims copyright to this source code.  In place of
-** a legal notice, here is a blessing:
-**
-**    May you do good and not evil.
-**    May you find forgiveness for yourself and forgive others.
-**    May you share freely, never taking more than you give.
-**
-******************************************************************************
-**
-** This module contains code that implements a parser for fts3 query strings
-** (the right-hand argument to the MATCH operator). Because the supported
-** syntax is relatively simple, the whole tokenizer/parser system is
-** hand-coded. The public interface to this module is declared in source
-** code file "fts3_expr.h".
-*/
-#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
-
-/*
-** By default, this module parses the legacy syntax that has been
-** traditionally used by fts3. Or, if SQLITE_ENABLE_FTS3_PARENTHESIS
-** is defined, then it uses the new syntax. The differences between
-** the new and the old syntaxes are:
-**
-**  a) The new syntax supports parenthesis. The old does not.
-**
-**  b) The new syntax supports the AND and NOT operators. The old does not.
-**
-**  c) The old syntax supports the "-" token qualifier. This is not
-**     supported by the new syntax (it is replaced by the NOT operator).
-**
-**  d) When using the old syntax, the OR operator has a greater precedence
-**     than an implicit AND. When using the new, both implicity and explicit
-**     AND operators have a higher precedence than OR.
-**
-** If compiled with SQLITE_TEST defined, then this module exports the
-** symbol "int sqlite3_fts3_enable_parentheses". Setting this variable
-** to zero causes the module to use the old syntax. If it is set to
-** non-zero the new syntax is activated. This is so both syntaxes can
-** be tested using a single build of testfixture.
-*/
-#ifdef SQLITE_TEST
-SQLITE_API int sqlite3_fts3_enable_parentheses = 0;
-#else
-# ifdef SQLITE_ENABLE_FTS3_PARENTHESIS
-#  define sqlite3_fts3_enable_parentheses 1
-# else
-#  define sqlite3_fts3_enable_parentheses 0
-# endif
-#endif
-
-/*
-** Default span for NEAR operators.
-*/
-#define SQLITE_FTS3_DEFAULT_NEAR_PARAM 10
-
-
-typedef struct ParseContext ParseContext;
-struct ParseContext {
-  sqlite3_tokenizer *pTokenizer;      /* Tokenizer module */
-  const char **azCol;                 /* Array of column names for fts3 table */
-  int nCol;                           /* Number of entries in azCol[] */
-  int iDefaultCol;                    /* Default column to query */
-  sqlite3_context *pCtx;              /* Write error message here */
-  int nNest;                          /* Number of nested brackets */
-};
-
-/*
-** This function is equivalent to the standard isspace() function.
-**
-** The standard isspace() can be awkward to use safely, because although it
-** is defined to accept an argument of type int, its behaviour when passed
-** an integer that falls outside of the range of the unsigned char type
-** is undefined (and sometimes, "undefined" means segfault). This wrapper
-** is defined to accept an argument of type char, and always returns 0 for
-** any values that fall outside of the range of the unsigned char type (i.e.
-** negative values).
-*/
-static int fts3isspace(char c){
-  return (c&0x80)==0 ? isspace(c) : 0;
-}
-
-/*
-** Extract the next token from buffer z (length n) using the tokenizer
-** and other information (column names etc.) in pParse. Create an Fts3Expr
-** structure of type FTSQUERY_PHRASE containing a phrase consisting of this
-** single token and set *ppExpr to point to it. If the end of the buffer is
-** reached before a token is found, set *ppExpr to zero. It is the
-** responsibility of the caller to eventually deallocate the allocated
-** Fts3Expr structure (if any) by passing it to sqlite3_free().
-**
-** Return SQLITE_OK if successful, or SQLITE_NOMEM if a memory allocation
-** fails.
-*/
-static int getNextToken(
-  ParseContext *pParse,                   /* fts3 query parse context */
-  int iCol,                               /* Value for Fts3Phrase.iColumn */
-  const char *z, int n,                   /* Input string */
-  Fts3Expr **ppExpr,                      /* OUT: expression */
-  int *pnConsumed                         /* OUT: Number of bytes consumed */
-){
-  sqlite3_tokenizer *pTokenizer = pParse->pTokenizer;
-  sqlite3_tokenizer_module const *pModule = pTokenizer->pModule;
-  int rc;
-  sqlite3_tokenizer_cursor *pCursor;
-  Fts3Expr *pRet = 0;
-  int nConsumed = 0;
-
-  rc = pModule->xOpen(pTokenizer, z, n, &pCursor);
-  if( rc==SQLITE_OK ){
-    const char *zToken;
-    int nToken, iStart, iEnd, iPosition;
-    int nByte;                               /* total space to allocate */
-
-    pCursor->pTokenizer = pTokenizer;
-    rc = pModule->xNext(pCursor, &zToken, &nToken, &iStart, &iEnd, &iPosition);
-
-    if( rc==SQLITE_OK ){
-      nByte = sizeof(Fts3Expr) + sizeof(Fts3Phrase) + nToken;
-      pRet = (Fts3Expr *)sqlite3_malloc(nByte);
-      if( !pRet ){
-        rc = SQLITE_NOMEM;
-      }else{
-        memset(pRet, 0, nByte);
-        pRet->eType = FTSQUERY_PHRASE;
-        pRet->pPhrase = (Fts3Phrase *)&pRet[1];
-        pRet->pPhrase->nToken = 1;
-        pRet->pPhrase->iColumn = iCol;
-        pRet->pPhrase->aToken[0].n = nToken;
-        pRet->pPhrase->aToken[0].z = (char *)&pRet->pPhrase[1];
-        memcpy(pRet->pPhrase->aToken[0].z, zToken, nToken);
-
-        if( iEnd<n && z[iEnd]=='*' ){
-          pRet->pPhrase->aToken[0].isPrefix = 1;
-          iEnd++;
-        }
-        if( !sqlite3_fts3_enable_parentheses && iStart>0 && z[iStart-1]=='-' ){
-          pRet->pPhrase->isNot = 1;
-        }
-      }
-      nConsumed = iEnd;
-    }
-
-    pModule->xClose(pCursor);
-  }
-
-  *pnConsumed = nConsumed;
-  *ppExpr = pRet;
-  return rc;
-}
-
-
-/*
-** Enlarge a memory allocation.  If an out-of-memory allocation occurs,
-** then free the old allocation.
-*/
-void *fts3ReallocOrFree(void *pOrig, int nNew){
-  void *pRet = sqlite3_realloc(pOrig, nNew);
-  if( !pRet ){
-    sqlite3_free(pOrig);
-  }
-  return pRet;
-}
-
-/*
-** Buffer zInput, length nInput, contains the contents of a quoted string
-** that appeared as part of an fts3 query expression. Neither quote character
-** is included in the buffer. This function attempts to tokenize the entire
-** input buffer and create an Fts3Expr structure of type FTSQUERY_PHRASE
-** containing the results.
-**
-** If successful, SQLITE_OK is returned and *ppExpr set to point at the
-** allocated Fts3Expr structure. Otherwise, either SQLITE_NOMEM (out of memory
-** error) or SQLITE_ERROR (tokenization error) is returned and *ppExpr set
-** to 0.
-*/
-static int getNextString(
-  ParseContext *pParse,                   /* fts3 query parse context */
-  const char *zInput, int nInput,         /* Input string */
-  Fts3Expr **ppExpr                       /* OUT: expression */
-){
-  sqlite3_tokenizer *pTokenizer = pParse->pTokenizer;
-  sqlite3_tokenizer_module const *pModule = pTokenizer->pModule;
-  int rc;
-  Fts3Expr *p = 0;
-  sqlite3_tokenizer_cursor *pCursor = 0;
-  char *zTemp = 0;
-  int nTemp = 0;
-
-  rc = pModule->xOpen(pTokenizer, zInput, nInput, &pCursor);
-  if( rc==SQLITE_OK ){
-    int ii;
-    pCursor->pTokenizer = pTokenizer;
-    for(ii=0; rc==SQLITE_OK; ii++){
-      const char *zToken;
-      int nToken, iBegin, iEnd, iPos;
-      rc = pModule->xNext(pCursor, &zToken, &nToken, &iBegin, &iEnd, &iPos);
-      if( rc==SQLITE_OK ){
-        int nByte = sizeof(Fts3Expr) + sizeof(Fts3Phrase);
-        p = fts3ReallocOrFree(p, nByte+ii*sizeof(struct PhraseToken));
-        zTemp = fts3ReallocOrFree(zTemp, nTemp + nToken);
-        if( !p || !zTemp ){
-          goto no_mem;
-        }
-        if( ii==0 ){
-          memset(p, 0, nByte);
-          p->pPhrase = (Fts3Phrase *)&p[1];
-        }
-        p->pPhrase = (Fts3Phrase *)&p[1];
-        p->pPhrase->nToken = ii+1;
-        p->pPhrase->aToken[ii].n = nToken;
-        memcpy(&zTemp[nTemp], zToken, nToken);
-        nTemp += nToken;
-        if( iEnd<nInput && zInput[iEnd]=='*' ){
-          p->pPhrase->aToken[ii].isPrefix = 1;
-        }else{
-          p->pPhrase->aToken[ii].isPrefix = 0;
-        }
-      }
-    }
-
-    pModule->xClose(pCursor);
-    pCursor = 0;
-  }
-
-  if( rc==SQLITE_DONE ){
-    int jj;
-    char *zNew;
-    int nNew = 0;
-    int nByte = sizeof(Fts3Expr) + sizeof(Fts3Phrase);
-    nByte += (p?(p->pPhrase->nToken-1):0) * sizeof(struct PhraseToken);
-    p = fts3ReallocOrFree(p, nByte + nTemp);
-    if( !p ){
-      goto no_mem;
-    }
-    if( zTemp ){
-      zNew = &(((char *)p)[nByte]);
-      memcpy(zNew, zTemp, nTemp);
-    }else{
-      memset(p, 0, nByte+nTemp);
-    }
-    p->pPhrase = (Fts3Phrase *)&p[1];
-    for(jj=0; jj<p->pPhrase->nToken; jj++){
-      p->pPhrase->aToken[jj].z = &zNew[nNew];
-      nNew += p->pPhrase->aToken[jj].n;
-    }
-    sqlite3_free(zTemp);
-    p->eType = FTSQUERY_PHRASE;
-    p->pPhrase->iColumn = pParse->iDefaultCol;
-    rc = SQLITE_OK;
-  }
-
-  *ppExpr = p;
-  return rc;
-no_mem:
-
-  if( pCursor ){
-    pModule->xClose(pCursor);
-  }
-  sqlite3_free(zTemp);
-  sqlite3_free(p);
-  *ppExpr = 0;
-  return SQLITE_NOMEM;
-}
-
-/*
-** Function getNextNode(), which is called by fts3ExprParse(), may itself
-** call fts3ExprParse(). So this forward declaration is required.
-*/
-static int fts3ExprParse(ParseContext *, const char *, int, Fts3Expr **, int *);
-
-/*
-** The output variable *ppExpr is populated with an allocated Fts3Expr
-** structure, or set to 0 if the end of the input buffer is reached.
-**
-** Returns an SQLite error code. SQLITE_OK if everything works, SQLITE_NOMEM
-** if a malloc failure occurs, or SQLITE_ERROR if a parse error is encountered.
-** If SQLITE_ERROR is returned, pContext is populated with an error message.
-*/
-static int getNextNode(
-  ParseContext *pParse,                   /* fts3 query parse context */
-  const char *z, int n,                   /* Input string */
-  Fts3Expr **ppExpr,                      /* OUT: expression */
-  int *pnConsumed                         /* OUT: Number of bytes consumed */
-){
-  static const struct Fts3Keyword {
-    char z[4];                            /* Keyword text */
-    unsigned char n;                      /* Length of the keyword */
-    unsigned char parenOnly;              /* Only valid in paren mode */
-    unsigned char eType;                  /* Keyword code */
-  } aKeyword[] = {
-    { "OR" ,  2, 0, FTSQUERY_OR   },
-    { "AND",  3, 1, FTSQUERY_AND  },
-    { "NOT",  3, 1, FTSQUERY_NOT  },
-    { "NEAR", 4, 0, FTSQUERY_NEAR }
-  };
-  int ii;
-  int iCol;
-  int iColLen;
-  int rc;
-  Fts3Expr *pRet = 0;
-
-  const char *zInput = z;
-  int nInput = n;
-
-  /* Skip over any whitespace before checking for a keyword, an open or
-  ** close bracket, or a quoted string.
-  */
-  while( nInput>0 && fts3isspace(*zInput) ){
-    nInput--;
-    zInput++;
-  }
-  if( nInput==0 ){
-    return SQLITE_DONE;
-  }
-
-  /* See if we are dealing with a keyword. */
-  for(ii=0; ii<(int)(sizeof(aKeyword)/sizeof(struct Fts3Keyword)); ii++){
-    const struct Fts3Keyword *pKey = &aKeyword[ii];
-
-    if( (pKey->parenOnly & ~sqlite3_fts3_enable_parentheses)!=0 ){
-      continue;
-    }
-
-    if( nInput>=pKey->n && 0==memcmp(zInput, pKey->z, pKey->n) ){
-      int nNear = SQLITE_FTS3_DEFAULT_NEAR_PARAM;
-      int nKey = pKey->n;
-      char cNext;
-
-      /* If this is a "NEAR" keyword, check for an explicit nearness. */
-      if( pKey->eType==FTSQUERY_NEAR ){
-        assert( nKey==4 );
-        if( zInput[4]=='/' && zInput[5]>='0' && zInput[5]<='9' ){
-          nNear = 0;
-          for(nKey=5; zInput[nKey]>='0' && zInput[nKey]<='9'; nKey++){
-            nNear = nNear * 10 + (zInput[nKey] - '0');
-          }
-        }
-      }
-
-      /* At this point this is probably a keyword. But for that to be true,
-      ** the next byte must contain either whitespace, an open or close
-      ** parenthesis, a quote character, or EOF.
-      */
-      cNext = zInput[nKey];
-      if( fts3isspace(cNext)
-       || cNext=='"' || cNext=='(' || cNext==')' || cNext==0
-      ){
         pRet = (Fts3Expr *)sqlite3_malloc(sizeof(Fts3Expr));
+        if( !pRet ){
+          return SQLITE_NOMEM;
+        }
         memset(pRet, 0, sizeof(Fts3Expr));
         pRet->eType = pKey->eType;
         pRet->nNear = nNear;
         *ppExpr = pRet;
         *pnConsumed = (zInput - z) + nKey;
@@ -105643,10 +100674,125 @@
 **       SQLite (in which case SQLITE_ENABLE_FTS3 is defined).
 */
 #if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
 
 
+/************** Include fts3_hash.h in the middle of fts3_hash.c *************/
+/************** Begin file fts3_hash.h ***************************************/
+/*
+** 2001 September 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This is the header file for the generic hash-table implemenation
+** used in SQLite.  We've modified it slightly to serve as a standalone
+** hash table implementation for the full-text indexing module.
+**
+*/
+#ifndef _FTS3_HASH_H_
+#define _FTS3_HASH_H_
+
+/* Forward declarations of structures. */
+typedef struct Fts3Hash Fts3Hash;
+typedef struct Fts3HashElem Fts3HashElem;
+
+/* A complete hash table is an instance of the following structure.
+** The internals of this structure are intended to be opaque -- client
+** code should not attempt to access or modify the fields of this structure
+** directly.  Change this structure only by using the routines below.
+** However, many of the "procedures" and "functions" for modifying and
+** accessing this structure are really macros, so we can't really make
+** this structure opaque.
+*/
+struct Fts3Hash {
+  char keyClass;          /* HASH_INT, _POINTER, _STRING, _BINARY */
+  char copyKey;           /* True if copy of key made on insert */
+  int count;              /* Number of entries in this table */
+  Fts3HashElem *first;    /* The first element of the array */
+  int htsize;             /* Number of buckets in the hash table */
+  struct _fts3ht {        /* the hash table */
+    int count;               /* Number of entries with this hash */
+    Fts3HashElem *chain;     /* Pointer to first entry with this hash */
+  } *ht;
+};
+
+/* Each element in the hash table is an instance of the following
+** structure.  All elements are stored on a single doubly-linked list.
+**
+** Again, this structure is intended to be opaque, but it can't really
+** be opaque because it is used by macros.
+*/
+struct Fts3HashElem {
+  Fts3HashElem *next, *prev; /* Next and previous elements in the table */
+  void *data;                /* Data associated with this element */
+  void *pKey; int nKey;      /* Key associated with this element */
+};
+
+/*
+** There are 2 different modes of operation for a hash table:
+**
+**   FTS3_HASH_STRING        pKey points to a string that is nKey bytes long
+**                           (including the null-terminator, if any).  Case
+**                           is respected in comparisons.
+**
+**   FTS3_HASH_BINARY        pKey points to binary data nKey bytes long.
+**                           memcmp() is used to compare keys.
+**
+** A copy of the key is made if the copyKey parameter to fts3HashInit is 1.
+*/
+#define FTS3_HASH_STRING    1
+#define FTS3_HASH_BINARY    2
+
+/*
+** Access routines.  To delete, insert a NULL pointer.
+*/
+SQLITE_PRIVATE void sqlite3Fts3HashInit(Fts3Hash*, int keytype, int copyKey);
+SQLITE_PRIVATE void *sqlite3Fts3HashInsert(Fts3Hash*, const void *pKey, int nKey, void *pData);
+SQLITE_PRIVATE void *sqlite3Fts3HashFind(const Fts3Hash*, const void *pKey, int nKey);
+SQLITE_PRIVATE void sqlite3Fts3HashClear(Fts3Hash*);
+
+/*
+** Shorthand for the functions above
+*/
+#define fts3HashInit   sqlite3Fts3HashInit
+#define fts3HashInsert sqlite3Fts3HashInsert
+#define fts3HashFind   sqlite3Fts3HashFind
+#define fts3HashClear  sqlite3Fts3HashClear
+
+/*
+** Macros for looping over all elements of a hash table.  The idiom is
+** like this:
+**
+**   Fts3Hash h;
+**   Fts3HashElem *p;
+**   ...
+**   for(p=fts3HashFirst(&h); p; p=fts3HashNext(p)){
+**     SomeStructure *pData = fts3HashData(p);
+**     // do something with pData
+**   }
+*/
+#define fts3HashFirst(H)  ((H)->first)
+#define fts3HashNext(E)   ((E)->next)
+#define fts3HashData(E)   ((E)->data)
+#define fts3HashKey(E)    ((E)->pKey)
+#define fts3HashKeysize(E) ((E)->nKey)
+
+/*
+** Number of entries in a hash table
+*/
+#define fts3HashCount(H)  ((H)->count)
+
+#endif /* _FTS3_HASH_H_ */
+
+/************** End of fts3_hash.h *******************************************/
+/************** Continuing where we left off in fts3_hash.c ******************/
 
 /*
 ** Malloc and Free functions
 */
 static void *fts3HashMalloc(int n){
@@ -105668,11 +100814,11 @@
 ** FTS3_HASH_BINARY or FTS3_HASH_STRING.  The value of keyClass
 ** determines what kind of key the hash table will use.  "copyKey" is
 ** true if the hash table should make its own private copy of keys and
 ** false if it should just use the supplied pointer.
 */
-SQLITE_PRIVATE void sqlite3Fts3HashInit(fts3Hash *pNew, int keyClass, int copyKey){
+SQLITE_PRIVATE void sqlite3Fts3HashInit(Fts3Hash *pNew, int keyClass, int copyKey){
   assert( pNew!=0 );
   assert( keyClass>=FTS3_HASH_STRING && keyClass<=FTS3_HASH_BINARY );
   pNew->keyClass = keyClass;
   pNew->copyKey = copyKey;
   pNew->first = 0;
@@ -105683,21 +100829,21 @@
 
 /* Remove all entries from a hash table.  Reclaim all memory.
 ** Call this routine to delete a hash table or to reset a hash table
 ** to the empty state.
 */
-SQLITE_PRIVATE void sqlite3Fts3HashClear(fts3Hash *pH){
-  fts3HashElem *elem;         /* For looping over all elements of the table */
+SQLITE_PRIVATE void sqlite3Fts3HashClear(Fts3Hash *pH){
+  Fts3HashElem *elem;         /* For looping over all elements of the table */
 
   assert( pH!=0 );
   elem = pH->first;
   pH->first = 0;
   fts3HashFree(pH->ht);
   pH->ht = 0;
   pH->htsize = 0;
   while( elem ){
-    fts3HashElem *next_elem = elem->next;
+    Fts3HashElem *next_elem = elem->next;
     if( pH->copyKey && elem->pKey ){
       fts3HashFree(elem->pKey);
     }
     fts3HashFree(elem);
     elem = next_elem;
@@ -105776,15 +100922,15 @@
 }
 
 /* Link an element into the hash table
 */
 static void fts3HashInsertElement(
-  fts3Hash *pH,            /* The complete hash table */
+  Fts3Hash *pH,            /* The complete hash table */
   struct _fts3ht *pEntry,  /* The entry into which pNew is inserted */
-  fts3HashElem *pNew       /* The element to be inserted */
-){
-  fts3HashElem *pHead;     /* First element already in pEntry */
+  Fts3HashElem *pNew       /* The element to be inserted */
+){
+  Fts3HashElem *pHead;     /* First element already in pEntry */
   pHead = pEntry->chain;
   if( pHead ){
     pNew->next = pHead;
     pNew->prev = pHead->prev;
     if( pHead->prev ){ pHead->prev->next = pNew; }
@@ -105803,13 +100949,13 @@
 
 /* Resize the hash table so that it cantains "new_size" buckets.
 ** "new_size" must be a power of 2.  The hash table might fail
 ** to resize if sqliteMalloc() fails.
 */
-static void fts3Rehash(fts3Hash *pH, int new_size){
+static void fts3Rehash(Fts3Hash *pH, int new_size){
   struct _fts3ht *new_ht;          /* The new hash table */
-  fts3HashElem *elem, *next_elem;  /* For looping over existing elements */
+  Fts3HashElem *elem, *next_elem;  /* For looping over existing elements */
   int (*xHash)(const void*,int);   /* The hash function */
 
   assert( (new_size & (new_size-1))==0 );
   new_ht = (struct _fts3ht *)fts3HashMalloc( new_size*sizeof(struct _fts3ht) );
   if( new_ht==0 ) return;
@@ -105826,17 +100972,17 @@
 
 /* This function (for internal use only) locates an element in an
 ** hash table that matches the given key.  The hash for this key has
 ** already been computed and is passed as the 4th parameter.
 */
-static fts3HashElem *fts3FindElementByHash(
-  const fts3Hash *pH, /* The pH to be searched */
+static Fts3HashElem *fts3FindElementByHash(
+  const Fts3Hash *pH, /* The pH to be searched */
   const void *pKey,   /* The key we are searching for */
   int nKey,
   int h               /* The hash for this key. */
 ){
-  fts3HashElem *elem;            /* Used to loop thru the element list */
+  Fts3HashElem *elem;            /* Used to loop thru the element list */
   int count;                     /* Number of elements left to test */
   int (*xCompare)(const void*,int,const void*,int);  /* comparison function */
 
   if( pH->ht ){
     struct _fts3ht *pEntry = &pH->ht[h];
@@ -105855,12 +101001,12 @@
 
 /* Remove a single entry from the hash table given a pointer to that
 ** element and a hash on the element's key.
 */
 static void fts3RemoveElementByHash(
-  fts3Hash *pH,         /* The pH containing "elem" */
-  fts3HashElem* elem,   /* The element to be removed from the pH */
+  Fts3Hash *pH,         /* The pH containing "elem" */
+  Fts3HashElem* elem,   /* The element to be removed from the pH */
   int h                 /* Hash value for the element */
 ){
   struct _fts3ht *pEntry;
   if( elem->prev ){
     elem->prev->next = elem->next;
@@ -105892,13 +101038,13 @@
 
 /* Attempt to locate an element of the hash table pH with a key
 ** that matches pKey,nKey.  Return the data for this element if it is
 ** found, or NULL if there is no match.
 */
-SQLITE_PRIVATE void *sqlite3Fts3HashFind(const fts3Hash *pH, const void *pKey, int nKey){
+SQLITE_PRIVATE void *sqlite3Fts3HashFind(const Fts3Hash *pH, const void *pKey, int nKey){
   int h;                 /* A hash on key */
-  fts3HashElem *elem;    /* The element that matches key */
+  Fts3HashElem *elem;    /* The element that matches key */
   int (*xHash)(const void*,int);  /* The hash function */
 
   if( pH==0 || pH->ht==0 ) return 0;
   xHash = ftsHashFunction(pH->keyClass);
   assert( xHash!=0 );
@@ -105922,19 +101068,19 @@
 **
 ** If the "data" parameter to this function is NULL, then the
 ** element corresponding to "key" is removed from the hash table.
 */
 SQLITE_PRIVATE void *sqlite3Fts3HashInsert(
-  fts3Hash *pH,        /* The hash table to insert into */
+  Fts3Hash *pH,        /* The hash table to insert into */
   const void *pKey,    /* The key */
   int nKey,            /* Number of bytes in the key */
   void *data           /* The data */
 ){
   int hraw;                 /* Raw hash value of the key */
   int h;                    /* the hash of the key modulo hash table size */
-  fts3HashElem *elem;       /* Used to loop thru the element list */
-  fts3HashElem *new_elem;   /* New element added to the pH */
+  Fts3HashElem *elem;       /* Used to loop thru the element list */
+  Fts3HashElem *new_elem;   /* New element added to the pH */
   int (*xHash)(const void*,int);  /* The hash function */
 
   assert( pH!=0 );
   xHash = ftsHashFunction(pH->keyClass);
   assert( xHash!=0 );
@@ -105957,11 +101103,11 @@
     if( pH->htsize==0 ){
       pH->count = 0;
       return data;
     }
   }
-  new_elem = (fts3HashElem*)fts3HashMalloc( sizeof(fts3HashElem) );
+  new_elem = (Fts3HashElem*)fts3HashMalloc( sizeof(Fts3HashElem) );
   if( new_elem==0 ) return data;
   if( pH->copyKey && pKey!=0 ){
     new_elem->pKey = fts3HashMalloc( nKey );
     if( new_elem->pKey==0 ){
       fts3HashFree(new_elem);
@@ -106014,10 +101160,162 @@
 */
 #if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
 
 
 
+/************** Include fts3_tokenizer.h in the middle of fts3_porter.c ******/
+/************** Begin file fts3_tokenizer.h **********************************/
+/*
+** 2006 July 10
+**
+** The author disclaims copyright to this source code.
+**
+*************************************************************************
+** Defines the interface to tokenizers used by fulltext-search.  There
+** are three basic components:
+**
+** sqlite3_tokenizer_module is a singleton defining the tokenizer
+** interface functions.  This is essentially the class structure for
+** tokenizers.
+**
+** sqlite3_tokenizer is used to define a particular tokenizer, perhaps
+** including customization information defined at creation time.
+**
+** sqlite3_tokenizer_cursor is generated by a tokenizer to generate
+** tokens from a particular input.
+*/
+#ifndef _FTS3_TOKENIZER_H_
+#define _FTS3_TOKENIZER_H_
+
+/* TODO(shess) Only used for SQLITE_OK and SQLITE_DONE at this time.
+** If tokenizers are to be allowed to call sqlite3_*() functions, then
+** we will need a way to register the API consistently.
+*/
+
+/*
+** Structures used by the tokenizer interface. When a new tokenizer
+** implementation is registered, the caller provides a pointer to
+** an sqlite3_tokenizer_module containing pointers to the callback
+** functions that make up an implementation.
+**
+** When an fts3 table is created, it passes any arguments passed to
+** the tokenizer clause of the CREATE VIRTUAL TABLE statement to the
+** sqlite3_tokenizer_module.xCreate() function of the requested tokenizer
+** implementation. The xCreate() function in turn returns an
+** sqlite3_tokenizer structure representing the specific tokenizer to
+** be used for the fts3 table (customized by the tokenizer clause arguments).
+**
+** To tokenize an input buffer, the sqlite3_tokenizer_module.xOpen()
+** method is called. It returns an sqlite3_tokenizer_cursor object
+** that may be used to tokenize a specific input buffer based on
+** the tokenization rules supplied by a specific sqlite3_tokenizer
+** object.
+*/
+typedef struct sqlite3_tokenizer_module sqlite3_tokenizer_module;
+typedef struct sqlite3_tokenizer sqlite3_tokenizer;
+typedef struct sqlite3_tokenizer_cursor sqlite3_tokenizer_cursor;
+
+struct sqlite3_tokenizer_module {
+
+  /*
+  ** Structure version. Should always be set to 0.
+  */
+  int iVersion;
+
+  /*
+  ** Create a new tokenizer. The values in the argv[] array are the
+  ** arguments passed to the "tokenizer" clause of the CREATE VIRTUAL
+  ** TABLE statement that created the fts3 table. For example, if
+  ** the following SQL is executed:
+  **
+  **   CREATE .. USING fts3( ... , tokenizer <tokenizer-name> arg1 arg2)
+  **
+  ** then argc is set to 2, and the argv[] array contains pointers
+  ** to the strings "arg1" and "arg2".
+  **
+  ** This method should return either SQLITE_OK (0), or an SQLite error
+  ** code. If SQLITE_OK is returned, then *ppTokenizer should be set
+  ** to point at the newly created tokenizer structure. The generic
+  ** sqlite3_tokenizer.pModule variable should not be initialised by
+  ** this callback. The caller will do so.
+  */
+  int (*xCreate)(
+    int argc,                           /* Size of argv array */
+    const char *const*argv,             /* Tokenizer argument strings */
+    sqlite3_tokenizer **ppTokenizer     /* OUT: Created tokenizer */
+  );
+
+  /*
+  ** Destroy an existing tokenizer. The fts3 module calls this method
+  ** exactly once for each successful call to xCreate().
+  */
+  int (*xDestroy)(sqlite3_tokenizer *pTokenizer);
+
+  /*
+  ** Create a tokenizer cursor to tokenize an input buffer. The caller
+  ** is responsible for ensuring that the input buffer remains valid
+  ** until the cursor is closed (using the xClose() method).
+  */
+  int (*xOpen)(
+    sqlite3_tokenizer *pTokenizer,       /* Tokenizer object */
+    const char *pInput, int nBytes,      /* Input buffer */
+    sqlite3_tokenizer_cursor **ppCursor  /* OUT: Created tokenizer cursor */
+  );
+
+  /*
+  ** Destroy an existing tokenizer cursor. The fts3 module calls this
+  ** method exactly once for each successful call to xOpen().
+  */
+  int (*xClose)(sqlite3_tokenizer_cursor *pCursor);
+
+  /*
+  ** Retrieve the next token from the tokenizer cursor pCursor. This
+  ** method should either return SQLITE_OK and set the values of the
+  ** "OUT" variables identified below, or SQLITE_DONE to indicate that
+  ** the end of the buffer has been reached, or an SQLite error code.
+  **
+  ** *ppToken should be set to point at a buffer containing the
+  ** normalized version of the token (i.e. after any case-folding and/or
+  ** stemming has been performed). *pnBytes should be set to the length
+  ** of this buffer in bytes. The input text that generated the token is
+  ** identified by the byte offsets returned in *piStartOffset and
+  ** *piEndOffset. *piStartOffset should be set to the index of the first
+  ** byte of the token in the input buffer. *piEndOffset should be set
+  ** to the index of the first byte just past the end of the token in
+  ** the input buffer.
+  **
+  ** The buffer *ppToken is set to point at is managed by the tokenizer
+  ** implementation. It is only required to be valid until the next call
+  ** to xNext() or xClose().
+  */
+  /* TODO(shess) current implementation requires pInput to be
+  ** nul-terminated.  This should either be fixed, or pInput/nBytes
+  ** should be converted to zInput.
+  */
+  int (*xNext)(
+    sqlite3_tokenizer_cursor *pCursor,   /* Tokenizer cursor */
+    const char **ppToken, int *pnBytes,  /* OUT: Normalized text for token */
+    int *piStartOffset,  /* OUT: Byte offset of token in input buffer */
+    int *piEndOffset,    /* OUT: Byte offset of end of token in input buffer */
+    int *piPosition      /* OUT: Number of tokens returned before this one */
+  );
+};
+
+struct sqlite3_tokenizer {
+  const sqlite3_tokenizer_module *pModule;  /* The module for this tokenizer */
+  /* Tokenizer implementations will typically add additional fields */
+};
+
+struct sqlite3_tokenizer_cursor {
+  sqlite3_tokenizer *pTokenizer;       /* Tokenizer for this cursor. */
+  /* Tokenizer implementations will typically add additional fields */
+};
+
+#endif /* _FTS3_TOKENIZER_H_ */
+
+/************** End of fts3_tokenizer.h **************************************/
+/************** Continuing where we left off in fts3_porter.c ****************/
 
 /*
 ** Class derived from sqlite3_tokenizer
 */
 typedef struct porter_tokenizer {
@@ -106682,18 +101980,18 @@
 static void scalarFunc(
   sqlite3_context *context,
   int argc,
   sqlite3_value **argv
 ){
-  fts3Hash *pHash;
+  Fts3Hash *pHash;
   void *pPtr = 0;
   const unsigned char *zName;
   int nName;
 
   assert( argc==1 || argc==2 );
 
-  pHash = (fts3Hash *)sqlite3_user_data(context);
+  pHash = (Fts3Hash *)sqlite3_user_data(context);
 
   zName = sqlite3_value_text(argv[0]);
   nName = sqlite3_value_bytes(argv[0])+1;
 
   if( argc==2 ){
@@ -106719,10 +102017,132 @@
     }
   }
 
   sqlite3_result_blob(context, (void *)&pPtr, sizeof(pPtr), SQLITE_TRANSIENT);
 }
+
+static int fts3IsIdChar(char c){
+  static const char isFtsIdChar[] = {
+      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 0x */
+      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 1x */
+      0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 2x */
+      1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,  /* 3x */
+      0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 4x */
+      1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1,  /* 5x */
+      0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 6x */
+      1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0,  /* 7x */
+  };
+  return (c&0x80 || isFtsIdChar[(int)(c)]);
+}
+
+SQLITE_PRIVATE const char *sqlite3Fts3NextToken(const char *zStr, int *pn){
+  const char *z1;
+  const char *z2 = 0;
+
+  /* Find the start of the next token. */
+  z1 = zStr;
+  while( z2==0 ){
+    switch( *z1 ){
+      case '\0': return 0;        /* No more tokens here */
+      case '\'':
+      case '"':
+      case '`': {
+        z2 = &z1[1];
+        while( *z2 && (z2[0]!=*z1 || z2[1]==*z1) ) z2++;
+        if( *z2 ) z2++;
+        break;
+      }
+      case '[':
+        z2 = &z1[1];
+        while( *z2 && z2[0]!=']' ) z2++;
+        if( *z2 ) z2++;
+        break;
+
+      default:
+        if( fts3IsIdChar(*z1) ){
+          z2 = &z1[1];
+          while( fts3IsIdChar(*z2) ) z2++;
+        }else{
+          z1++;
+        }
+    }
+  }
+
+  *pn = (z2-z1);
+  return z1;
+}
+
+SQLITE_PRIVATE int sqlite3Fts3InitTokenizer(
+  Fts3Hash *pHash,                /* Tokenizer hash table */
+  const char *zArg,               /* Possible tokenizer specification */
+  sqlite3_tokenizer **ppTok,      /* OUT: Tokenizer (if applicable) */
+  const char **pzTokenizer,       /* OUT: Set to zArg if is tokenizer */
+  char **pzErr                    /* OUT: Set to malloced error message */
+){
+  int rc;
+  char *z = (char *)zArg;
+  int n;
+  char *zCopy;
+  char *zEnd;                     /* Pointer to nul-term of zCopy */
+  sqlite3_tokenizer_module *m;
+
+  if( !z ){
+    zCopy = sqlite3_mprintf("simple");
+  }else{
+    while( (*z&0x80) && isspace(*z) ) z++;
+    if( sqlite3_strnicmp(z, "tokenize", 8) || fts3IsIdChar(z[8])){
+      return SQLITE_OK;
+    }
+    zCopy = sqlite3_mprintf("%s", &z[8]);
+    *pzTokenizer = zArg;
+  }
+  if( !zCopy ){
+    return SQLITE_NOMEM;
+  }
+
+  zEnd = &zCopy[strlen(zCopy)];
+
+  z = (char *)sqlite3Fts3NextToken(zCopy, &n);
+  z[n] = '\0';
+  sqlite3Fts3Dequote(z);
+
+  m = (sqlite3_tokenizer_module *)sqlite3Fts3HashFind(pHash, z, strlen(z)+1);
+  if( !m ){
+    *pzErr = sqlite3_mprintf("unknown tokenizer: %s", z);
+    rc = SQLITE_ERROR;
+  }else{
+    char const **aArg = 0;
+    int iArg = 0;
+    z = &z[n+1];
+    while( z<zEnd && (z = (char *)sqlite3Fts3NextToken(z, &n)) ){
+      int nNew = sizeof(char *)*(iArg+1);
+      char const **aNew = (const char **)sqlite3_realloc(aArg, nNew);
+      if( !aNew ){
+        sqlite3_free(zCopy);
+        sqlite3_free(aArg);
+        return SQLITE_NOMEM;
+      }
+      aArg = aNew;
+      aArg[iArg++] = z;
+      z[n] = '\0';
+      sqlite3Fts3Dequote(z);
+      z = &z[n+1];
+    }
+    rc = m->xCreate(iArg, aArg, ppTok);
+    assert( rc!=SQLITE_OK || *ppTok );
+    if( rc!=SQLITE_OK ){
+      *pzErr = sqlite3_mprintf("unknown tokenizer: %s", z);
+    }else{
+      (*ppTok)->pModule = m;
+    }
+    sqlite3_free(aArg);
+  }
+
+  sqlite3_free(zCopy);
+  return rc;
+}
+
 
 #ifdef SQLITE_TEST
 
 
 /*
@@ -106754,11 +102174,11 @@
 static void testFunc(
   sqlite3_context *context,
   int argc,
   sqlite3_value **argv
 ){
-  fts3Hash *pHash;
+  Fts3Hash *pHash;
   sqlite3_tokenizer_module *p;
   sqlite3_tokenizer *pTokenizer = 0;
   sqlite3_tokenizer_cursor *pCsr = 0;
 
   const char *zErr = 0;
@@ -106787,11 +102207,11 @@
 
   if( argc==3 ){
     zArg = (const char *)sqlite3_value_text(argv[1]);
   }
 
-  pHash = (fts3Hash *)sqlite3_user_data(context);
+  pHash = (Fts3Hash *)sqlite3_user_data(context);
   p = (sqlite3_tokenizer_module *)sqlite3Fts3HashFind(pHash, zName, nName+1);
 
   if( !p ){
     char *zErr = sqlite3_mprintf("unknown tokenizer: %s", zName);
     sqlite3_result_error(context, zErr, -1);
@@ -106956,11 +102376,11 @@
 ** The third argument to this function, zName, is used as the name
 ** of both the scalar and, if created, the virtual table.
 */
 SQLITE_PRIVATE int sqlite3Fts3InitHashTable(
   sqlite3 *db,
-  fts3Hash *pHash,
+  Fts3Hash *pHash,
   const char *zName
 ){
   int rc = SQLITE_OK;
   void *p = (void *)pHash;
   const int any = SQLITE_ANY;
@@ -107219,10 +102639,2911 @@
 }
 
 #endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
 
 /************** End of fts3_tokenizer1.c *************************************/
+/************** Begin file fts3_write.c **************************************/
+/*
+** 2009 Oct 23
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file is part of the SQLite FTS3 extension module. Specifically,
+** this file contains code to insert, update and delete rows from FTS3
+** tables. It also contains code to merge FTS3 b-tree segments. Some
+** of the sub-routines used to merge segments are also used by the query
+** code in fts3.c.
+*/
+
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+
+#define INTERIOR_MAX 2048         /* Soft limit for segment node size */
+#define LEAF_MAX 2048             /* Soft limit for segment leaf size */
+
+typedef struct PendingList PendingList;
+typedef struct SegmentNode SegmentNode;
+typedef struct SegmentWriter SegmentWriter;
+
+/*
+** Data structure used while accumulating terms in the pending-terms hash
+** table. The hash table entry maps from term (a string) to a malloced
+** instance of this structure.
+*/
+struct PendingList {
+  int nData;
+  char *aData;
+  int nSpace;
+  sqlite3_int64 iLastDocid;
+  sqlite3_int64 iLastCol;
+  sqlite3_int64 iLastPos;
+};
+
+/*
+** An instance of this structure is used to iterate through the terms on
+** a contiguous set of segment b-tree leaf nodes. Although the details of
+** this structure are only manipulated by code in this file, opaque handles
+** of type Fts3SegReader* are also used by code in fts3.c to iterate through
+** terms when querying the full-text index. See functions:
+**
+**   sqlite3Fts3SegReaderNew()
+**   sqlite3Fts3SegReaderFree()
+**   sqlite3Fts3SegReaderIterate()
+*/
+struct Fts3SegReader {
+  int iIdx;                       /* Index within level */
+  sqlite3_int64 iStartBlock;
+  sqlite3_int64 iEndBlock;
+  sqlite3_stmt *pStmt;            /* SQL Statement to access leaf nodes */
+  char *aNode;                    /* Pointer to node data (or NULL) */
+  int nNode;                      /* Size of buffer at aNode (or 0) */
+  int nTermAlloc;                 /* Allocated size of zTerm buffer */
+
+  /* Variables set by fts3SegReaderNext(). These may be read directly
+  ** by the caller. They are valid from the time SegmentReaderNew() returns
+  ** until SegmentReaderNext() returns something other than SQLITE_OK
+  ** (i.e. SQLITE_DONE).
+  */
+  int nTerm;                      /* Number of bytes in current term */
+  char *zTerm;                    /* Pointer to current term */
+  char *aDoclist;                 /* Pointer to doclist of current entry */
+  int nDoclist;                   /* Size of doclist in current entry */
+
+  /* The following variables are used to iterate through the current doclist */
+  char *pOffsetList;
+  sqlite3_int64 iDocid;
+};
+
+/*
+** An instance of this structure is used to create a segment b-tree in the
+** database. The internal details of this type are only accessed by the
+** following functions:
+**
+**   fts3SegWriterAdd()
+**   fts3SegWriterFlush()
+**   fts3SegWriterFree()
+*/
+struct SegmentWriter {
+  SegmentNode *pTree;             /* Pointer to interior tree structure */
+  sqlite3_int64 iFirst;           /* First slot in %_segments written */
+  sqlite3_int64 iFree;            /* Next free slot in %_segments */
+  char *zTerm;                    /* Pointer to previous term buffer */
+  int nTerm;                      /* Number of bytes in zTerm */
+  int nMalloc;                    /* Size of malloc'd buffer at zMalloc */
+  char *zMalloc;                  /* Malloc'd space (possibly) used for zTerm */
+  int nSize;                      /* Size of allocation at aData */
+  int nData;                      /* Bytes of data in aData */
+  char *aData;                    /* Pointer to block from malloc() */
+};
+
+/*
+** Type SegmentNode is used by the following three functions to create
+** the interior part of the segment b+-tree structures (everything except
+** the leaf nodes). These functions and type are only ever used by code
+** within the fts3SegWriterXXX() family of functions described above.
+**
+**   fts3NodeAddTerm()
+**   fts3NodeWrite()
+**   fts3NodeFree()
+*/
+struct SegmentNode {
+  SegmentNode *pParent;           /* Parent node (or NULL for root node) */
+  SegmentNode *pRight;            /* Pointer to right-sibling */
+  SegmentNode *pLeftmost;         /* Pointer to left-most node of this depth */
+  int nEntry;                     /* Number of terms written to node so far */
+  char *zTerm;                    /* Pointer to previous term buffer */
+  int nTerm;                      /* Number of bytes in zTerm */
+  int nMalloc;                    /* Size of malloc'd buffer at zMalloc */
+  char *zMalloc;                  /* Malloc'd space (possibly) used for zTerm */
+  int nData;                      /* Bytes of valid data so far */
+  char *aData;                    /* Node data */
+};
+
+/*
+** Valid values for the second argument to fts3SqlStmt().
+*/
+#define SQL_DELETE_CONTENT             0
+#define SQL_IS_EMPTY                   1
+#define SQL_DELETE_ALL_CONTENT         2
+#define SQL_DELETE_ALL_SEGMENTS        3
+#define SQL_DELETE_ALL_SEGDIR          4
+#define SQL_SELECT_CONTENT_BY_ROWID    5
+#define SQL_NEXT_SEGMENT_INDEX         6
+#define SQL_INSERT_SEGMENTS            7
+#define SQL_NEXT_SEGMENTS_ID           8
+#define SQL_INSERT_SEGDIR              9
+#define SQL_SELECT_LEVEL              10
+#define SQL_SELECT_ALL_LEVEL          11
+#define SQL_SELECT_LEVEL_COUNT        12
+#define SQL_SELECT_SEGDIR_COUNT_MAX   13
+#define SQL_DELETE_SEGDIR_BY_LEVEL    14
+#define SQL_DELETE_SEGMENTS_RANGE     15
+#define SQL_CONTENT_INSERT            16
+#define SQL_GET_BLOCK                 17
+
+/*
+** This function is used to obtain an SQLite prepared statement handle
+** for the statement identified by the second argument. If successful,
+** *pp is set to the requested statement handle and SQLITE_OK returned.
+** Otherwise, an SQLite error code is returned and *pp is set to 0.
+**
+** If argument apVal is not NULL, then it must point to an array with
+** at least as many entries as the requested statement has bound
+** parameters. The values are bound to the statements parameters before
+** returning.
+*/
+static int fts3SqlStmt(
+  Fts3Table *p,                   /* Virtual table handle */
+  int eStmt,                      /* One of the SQL_XXX constants above */
+  sqlite3_stmt **pp,              /* OUT: Statement handle */
+  sqlite3_value **apVal           /* Values to bind to statement */
+){
+  const char *azSql[] = {
+/* 0  */  "DELETE FROM %Q.'%q_content' WHERE rowid = ?",
+/* 1  */  "SELECT NOT EXISTS(SELECT docid FROM %Q.'%q_content' WHERE rowid!=?)",
+/* 2  */  "DELETE FROM %Q.'%q_content'",
+/* 3  */  "DELETE FROM %Q.'%q_segments'",
+/* 4  */  "DELETE FROM %Q.'%q_segdir'",
+/* 5  */  "SELECT * FROM %Q.'%q_content' WHERE rowid=?",
+/* 6  */  "SELECT coalesce(max(idx)+1, 0) FROM %Q.'%q_segdir' WHERE level=?",
+/* 7  */  "INSERT INTO %Q.'%q_segments'(blockid, block) VALUES(?, ?)",
+/* 8  */  "SELECT coalesce(max(blockid)+1, 1) FROM %Q.'%q_segments'",
+/* 9  */  "INSERT INTO %Q.'%q_segdir' VALUES(?,?,?,?,?,?)",
+
+          /* Return segments in order from oldest to newest.*/
+/* 10 */  "SELECT idx, start_block, leaves_end_block, end_block, root "
+            "FROM %Q.'%q_segdir' WHERE level = ? ORDER BY idx ASC",
+/* 11 */  "SELECT idx, start_block, leaves_end_block, end_block, root "
+            "FROM %Q.'%q_segdir' ORDER BY level DESC, idx ASC",
+
+/* 12 */  "SELECT count(*) FROM %Q.'%q_segdir' WHERE level = ?",
+/* 13 */  "SELECT count(*), max(level) FROM %Q.'%q_segdir'",
+
+/* 14 */  "DELETE FROM %Q.'%q_segdir' WHERE level = ?",
+/* 15 */  "DELETE FROM %Q.'%q_segments' WHERE blockid BETWEEN ? AND ?",
+/* 16 */  "INSERT INTO %Q.'%q_content' VALUES(%z)",
+/* 17 */  "SELECT block FROM %Q.'%q_segments' WHERE blockid = ?",
+  };
+  int rc = SQLITE_OK;
+  sqlite3_stmt *pStmt;
+
+  assert( SizeofArray(azSql)==SizeofArray(p->aStmt) );
+  assert( eStmt<SizeofArray(azSql) && eStmt>=0 );
+
+  pStmt = p->aStmt[eStmt];
+  if( !pStmt ){
+    char *zSql;
+    if( eStmt==SQL_CONTENT_INSERT ){
+      int i;                      /* Iterator variable */
+      char *zVarlist;             /* The "?, ?, ..." string */
+      zVarlist = (char *)sqlite3_malloc(2*p->nColumn+2);
+      if( !zVarlist ){
+        *pp = 0;
+        return SQLITE_NOMEM;
+      }
+      zVarlist[0] = '?';
+      zVarlist[p->nColumn*2+1] = '\0';
+      for(i=1; i<=p->nColumn; i++){
+        zVarlist[i*2-1] = ',';
+        zVarlist[i*2] = '?';
+      }
+      zSql = sqlite3_mprintf(azSql[eStmt], p->zDb, p->zName, zVarlist);
+    }else{
+      zSql = sqlite3_mprintf(azSql[eStmt], p->zDb, p->zName);
+    }
+    if( !zSql ){
+      rc = SQLITE_NOMEM;
+    }else{
+      rc = sqlite3_prepare_v2(p->db, zSql, -1, &pStmt, NULL);
+      sqlite3_free(zSql);
+      assert( rc==SQLITE_OK || pStmt==0 );
+      p->aStmt[eStmt] = pStmt;
+    }
+  }
+  if( apVal ){
+    int i;
+    int nParam = sqlite3_bind_parameter_count(pStmt);
+    for(i=0; rc==SQLITE_OK && i<nParam; i++){
+      rc = sqlite3_bind_value(pStmt, i+1, apVal[i]);
+    }
+  }
+  *pp = pStmt;
+  return rc;
+}
+
+/*
+** Similar to fts3SqlStmt(). Except, after binding the parameters in
+** array apVal[] to the SQL statement identified by eStmt, the statement
+** is executed.
+**
+** Returns SQLITE_OK if the statement is successfully executed, or an
+** SQLite error code otherwise.
+*/
+static int fts3SqlExec(Fts3Table *p, int eStmt, sqlite3_value **apVal){
+  sqlite3_stmt *pStmt;
+  int rc = fts3SqlStmt(p, eStmt, &pStmt, apVal);
+  if( rc==SQLITE_OK ){
+    sqlite3_step(pStmt);
+    rc = sqlite3_reset(pStmt);
+  }
+  return rc;
+}
+
+
+/*
+** Read a single block from the %_segments table. If the specified block
+** does not exist, return SQLITE_CORRUPT. If some other error (malloc, IO
+** etc.) occurs, return the appropriate SQLite error code.
+**
+** Otherwise, if successful, set *pzBlock to point to a buffer containing
+** the block read from the database, and *pnBlock to the size of the read
+** block in bytes.
+**
+** WARNING: The returned buffer is only valid until the next call to
+** sqlite3Fts3ReadBlock().
+*/
+SQLITE_PRIVATE int sqlite3Fts3ReadBlock(
+  Fts3Table *p,
+  sqlite3_int64 iBlock,
+  char const **pzBlock,
+  int *pnBlock
+){
+  sqlite3_stmt *pStmt;
+  int rc = fts3SqlStmt(p, SQL_GET_BLOCK, &pStmt, 0);
+  if( rc!=SQLITE_OK ) return rc;
+  sqlite3_reset(pStmt);
+
+  sqlite3_bind_int64(pStmt, 1, iBlock);
+  rc = sqlite3_step(pStmt);
+  if( rc!=SQLITE_ROW ){
+    return SQLITE_CORRUPT;
+  }
+
+  *pnBlock = sqlite3_column_bytes(pStmt, 0);
+  *pzBlock = (char *)sqlite3_column_blob(pStmt, 0);
+  if( !*pzBlock ){
+    return SQLITE_NOMEM;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Set *ppStmt to a statement handle that may be used to iterate through
+** all rows in the %_segdir table, from oldest to newest. If successful,
+** return SQLITE_OK. If an error occurs while preparing the statement,
+** return an SQLite error code.
+**
+** There is only ever one instance of this SQL statement compiled for
+** each FTS3 table.
+**
+** The statement returns the following columns from the %_segdir table:
+**
+**   0: idx
+**   1: start_block
+**   2: leaves_end_block
+**   3: end_block
+**   4: root
+*/
+SQLITE_PRIVATE int sqlite3Fts3AllSegdirs(Fts3Table *p, sqlite3_stmt **ppStmt){
+  return fts3SqlStmt(p, SQL_SELECT_ALL_LEVEL, ppStmt, 0);
+}
+
+
+/*
+** Append a single varint to a PendingList buffer. SQLITE_OK is returned
+** if successful, or an SQLite error code otherwise.
+**
+** This function also serves to allocate the PendingList structure itself.
+** For example, to create a new PendingList structure containing two
+** varints:
+**
+**   PendingList *p = 0;
+**   fts3PendingListAppendVarint(&p, 1);
+**   fts3PendingListAppendVarint(&p, 2);
+*/
+static int fts3PendingListAppendVarint(
+  PendingList **pp,               /* IN/OUT: Pointer to PendingList struct */
+  sqlite3_int64 i                 /* Value to append to data */
+){
+  PendingList *p = *pp;
+
+  /* Allocate or grow the PendingList as required. */
+  if( !p ){
+    p = sqlite3_malloc(sizeof(*p) + 100);
+    if( !p ){
+      return SQLITE_NOMEM;
+    }
+    p->nSpace = 100;
+    p->aData = (char *)&p[1];
+    p->nData = 0;
+  }
+  else if( p->nData+FTS3_VARINT_MAX+1>p->nSpace ){
+    int nNew = p->nSpace * 2;
+    p = sqlite3_realloc(p, sizeof(*p) + nNew);
+    if( !p ){
+      sqlite3_free(*pp);
+      *pp = 0;
+      return SQLITE_NOMEM;
+    }
+    p->nSpace = nNew;
+    p->aData = (char *)&p[1];
+  }
+
+  /* Append the new serialized varint to the end of the list. */
+  p->nData += sqlite3Fts3PutVarint(&p->aData[p->nData], i);
+  p->aData[p->nData] = '\0';
+  *pp = p;
+  return SQLITE_OK;
+}
+
+/*
+** Add a docid/column/position entry to a PendingList structure. Non-zero
+** is returned if the structure is sqlite3_realloced as part of adding
+** the entry. Otherwise, zero.
+**
+** If an OOM error occurs, *pRc is set to SQLITE_NOMEM before returning.
+** Zero is always returned in this case. Otherwise, if no OOM error occurs,
+** it is set to SQLITE_OK.
+*/
+static int fts3PendingListAppend(
+  PendingList **pp,               /* IN/OUT: PendingList structure */
+  sqlite3_int64 iDocid,           /* Docid for entry to add */
+  sqlite3_int64 iCol,             /* Column for entry to add */
+  sqlite3_int64 iPos,             /* Position of term for entry to add */
+  int *pRc                        /* OUT: Return code */
+){
+  PendingList *p = *pp;
+  int rc = SQLITE_OK;
+
+  assert( !p || p->iLastDocid<=iDocid );
+
+  if( !p || p->iLastDocid!=iDocid ){
+    sqlite3_int64 iDelta = iDocid - (p ? p->iLastDocid : 0);
+    if( p ){
+      assert( p->nData<p->nSpace );
+      assert( p->aData[p->nData]==0 );
+      p->nData++;
+    }
+    if( SQLITE_OK!=(rc = fts3PendingListAppendVarint(&p, iDelta)) ){
+      goto pendinglistappend_out;
+    }
+    p->iLastCol = -1;
+    p->iLastPos = 0;
+    p->iLastDocid = iDocid;
+  }
+  if( iCol>0 && p->iLastCol!=iCol ){
+    if( SQLITE_OK!=(rc = fts3PendingListAppendVarint(&p, 1))
+     || SQLITE_OK!=(rc = fts3PendingListAppendVarint(&p, iCol))
+    ){
+      goto pendinglistappend_out;
+    }
+    p->iLastCol = iCol;
+    p->iLastPos = 0;
+  }
+  if( iCol>=0 ){
+    assert( iPos>p->iLastPos || (iPos==0 && p->iLastPos==0) );
+    rc = fts3PendingListAppendVarint(&p, 2+iPos-p->iLastPos);
+    p->iLastPos = iPos;
+  }
+
+ pendinglistappend_out:
+  *pRc = rc;
+  if( p!=*pp ){
+    *pp = p;
+    return 1;
+  }
+  return 0;
+}
+
+/*
+** Tokenize the nul-terminated string zText and add all tokens to the
+** pending-terms hash-table. The docid used is that currently stored in
+** p->iPrevDocid, and the column is specified by argument iCol.
+**
+** If successful, SQLITE_OK is returned. Otherwise, an SQLite error code.
+*/
+static int fts3PendingTermsAdd(Fts3Table *p, const char *zText, int iCol){
+  int rc;
+  int iStart;
+  int iEnd;
+  int iPos;
+
+  char const *zToken;
+  int nToken;
+
+  sqlite3_tokenizer *pTokenizer = p->pTokenizer;
+  sqlite3_tokenizer_module const *pModule = pTokenizer->pModule;
+  sqlite3_tokenizer_cursor *pCsr;
+  int (*xNext)(sqlite3_tokenizer_cursor *pCursor,
+      const char**,int*,int*,int*,int*);
+
+  assert( pTokenizer && pModule );
+
+  rc = pModule->xOpen(pTokenizer, zText, -1, &pCsr);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+  pCsr->pTokenizer = pTokenizer;
+
+  xNext = pModule->xNext;
+  while( SQLITE_OK==rc
+      && SQLITE_OK==(rc = xNext(pCsr, &zToken, &nToken, &iStart, &iEnd, &iPos))
+  ){
+    PendingList *pList;
+
+    /* Positions cannot be negative; we use -1 as a terminator internally.
+    ** Tokens must have a non-zero length.
+    */
+    if( iPos<0 || !zToken || nToken<=0 ){
+      rc = SQLITE_ERROR;
+      break;
+    }
+
+    pList = (PendingList *)fts3HashFind(&p->pendingTerms, zToken, nToken);
+    if( pList ){
+      p->nPendingData -= (pList->nData + nToken + sizeof(Fts3HashElem));
+    }
+    if( fts3PendingListAppend(&pList, p->iPrevDocid, iCol, iPos, &rc) ){
+      if( pList==fts3HashInsert(&p->pendingTerms, zToken, nToken, pList) ){
+        /* Malloc failed while inserting the new entry. This can only
+        ** happen if there was no previous entry for this token.
+        */
+        assert( 0==fts3HashFind(&p->pendingTerms, zToken, nToken) );
+        sqlite3_free(pList);
+        rc = SQLITE_NOMEM;
+      }
+    }
+    if( rc==SQLITE_OK ){
+      p->nPendingData += (pList->nData + nToken + sizeof(Fts3HashElem));
+    }
+  }
+
+  pModule->xClose(pCsr);
+  return (rc==SQLITE_DONE ? SQLITE_OK : rc);
+}
+
+/*
+** Calling this function indicates that subsequent calls to
+** fts3PendingTermsAdd() are to add term/position-list pairs for the
+** contents of the document with docid iDocid.
+*/
+static int fts3PendingTermsDocid(Fts3Table *p, sqlite_int64 iDocid){
+  /* TODO(shess) Explore whether partially flushing the buffer on
+  ** forced-flush would provide better performance.  I suspect that if
+  ** we ordered the doclists by size and flushed the largest until the
+  ** buffer was half empty, that would let the less frequent terms
+  ** generate longer doclists.
+  */
+  if( iDocid<=p->iPrevDocid || p->nPendingData>FTS3_MAX_PENDING_DATA ){
+    int rc = sqlite3Fts3PendingTermsFlush(p);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+  p->iPrevDocid = iDocid;
+  return SQLITE_OK;
+}
+
+SQLITE_PRIVATE void sqlite3Fts3PendingTermsClear(Fts3Table *p){
+  Fts3HashElem *pElem;
+  for(pElem=fts3HashFirst(&p->pendingTerms); pElem; pElem=fts3HashNext(pElem)){
+    sqlite3_free(fts3HashData(pElem));
+  }
+  fts3HashClear(&p->pendingTerms);
+  p->nPendingData = 0;
+}
+
+/*
+** This function is called by the xUpdate() method as part of an INSERT
+** operation. It adds entries for each term in the new record to the
+** pendingTerms hash table.
+**
+** Argument apVal is the same as the similarly named argument passed to
+** fts3InsertData(). Parameter iDocid is the docid of the new row.
+*/
+static int fts3InsertTerms(Fts3Table *p, sqlite3_value **apVal){
+  int i;                          /* Iterator variable */
+  for(i=2; i<p->nColumn+2; i++){
+    const char *zText = (const char *)sqlite3_value_text(apVal[i]);
+    if( zText ){
+      int rc = fts3PendingTermsAdd(p, zText, i-2);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** This function is called by the xUpdate() method for an INSERT operation.
+** The apVal parameter is passed a copy of the apVal argument passed by
+** SQLite to the xUpdate() method. i.e:
+**
+**   apVal[0]                Not used for INSERT.
+**   apVal[1]                rowid
+**   apVal[2]                Left-most user-defined column
+**   ...
+**   apVal[p->nColumn+1]     Right-most user-defined column
+**   apVal[p->nColumn+2]     Hidden column with same name as table
+**   apVal[p->nColumn+3]     Hidden "docid" column (alias for rowid)
+*/
+static int fts3InsertData(
+  Fts3Table *p,                   /* Full-text table */
+  sqlite3_value **apVal,          /* Array of values to insert */
+  sqlite3_int64 *piDocid          /* OUT: Docid for row just inserted */
+){
+  int rc;                         /* Return code */
+  int i;                          /* Iterator variable */
+  sqlite3_stmt *pContentInsert;   /* INSERT INTO %_content VALUES(...) */
+
+  /* Locate the statement handle used to insert data into the %_content
+  ** table. The SQL for this statement is:
+  **
+  **   INSERT INTO %_content VALUES(?, ?, ?, ...)
+  **
+  ** The statement features N '?' variables, where N is the number of user
+  ** defined columns in the FTS3 table, plus one for the docid field.
+  */
+  rc = fts3SqlStmt(p, SQL_CONTENT_INSERT, &pContentInsert, &apVal[1]);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  /* There is a quirk here. The users INSERT statement may have specified
+  ** a value for the "rowid" field, for the "docid" field, or for both.
+  ** Which is a problem, since "rowid" and "docid" are aliases for the
+  ** same value. For example:
+  **
+  **   INSERT INTO fts3tbl(rowid, docid) VALUES(1, 2);
+  **
+  ** In FTS3, if a non-NULL docid value is specified, it is the value
+  ** inserted. Otherwise, the rowid value is used.
+  */
+  if( SQLITE_NULL!=sqlite3_value_type(apVal[3+p->nColumn]) ){
+    rc = sqlite3_bind_value(pContentInsert, 1, apVal[3+p->nColumn]);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+
+  /* Execute the statement to insert the record. Set *piDocid to the
+  ** new docid value.
+  */
+  sqlite3_step(pContentInsert);
+  rc = sqlite3_reset(pContentInsert);
+
+  *piDocid = sqlite3_last_insert_rowid(p->db);
+  return rc;
+}
+
+
+
+/*
+** Remove all data from the FTS3 table. Clear the hash table containing
+** pending terms.
+*/
+static int fts3DeleteAll(Fts3Table *p){
+  int rc;                         /* Return code */
+
+  /* Discard the contents of the pending-terms hash table. */
+  sqlite3Fts3PendingTermsClear(p);
+
+  /* Delete everything from the %_content, %_segments and %_segdir tables. */
+  rc = fts3SqlExec(p, SQL_DELETE_ALL_CONTENT, 0);
+  if( rc==SQLITE_OK ){
+    rc = fts3SqlExec(p, SQL_DELETE_ALL_SEGMENTS, 0);
+  }
+  if( rc==SQLITE_OK ){
+    rc = fts3SqlExec(p, SQL_DELETE_ALL_SEGDIR, 0);
+  }
+  return rc;
+}
+
+/*
+** The first element in the apVal[] array is assumed to contain the docid
+** (an integer) of a row about to be deleted. Remove all terms from the
+** full-text index.
+*/
+static int fts3DeleteTerms(Fts3Table *p, sqlite3_value **apVal){
+  int rc;
+  sqlite3_stmt *pSelect;
+
+  rc = fts3SqlStmt(p, SQL_SELECT_CONTENT_BY_ROWID, &pSelect, apVal);
+  if( rc==SQLITE_OK ){
+    if( SQLITE_ROW==sqlite3_step(pSelect) ){
+      int i;
+      for(i=1; i<=p->nColumn; i++){
+        const char *zText = (const char *)sqlite3_column_text(pSelect, i);
+        rc = fts3PendingTermsAdd(p, zText, -1);
+        if( rc!=SQLITE_OK ){
+          sqlite3_reset(pSelect);
+          return rc;
+        }
+      }
+    }
+  }
+
+  return sqlite3_reset(pSelect);
+}
+
+/*
+** Forward declaration to account for the circular dependency between
+** functions fts3SegmentMerge() and fts3AllocateSegdirIdx().
+*/
+static int fts3SegmentMerge(Fts3Table *, int);
+
+/*
+** This function allocates a new level iLevel index in the segdir table.
+** Usually, indexes are allocated within a level sequentially starting
+** with 0, so the allocated index is one greater than the value returned
+** by:
+**
+**   SELECT max(idx) FROM %_segdir WHERE level = :iLevel
+**
+** However, if there are already FTS3_MERGE_COUNT indexes at the requested
+** level, they are merged into a single level (iLevel+1) segment and the
+** allocated index is 0.
+**
+** If successful, *piIdx is set to the allocated index slot and SQLITE_OK
+** returned. Otherwise, an SQLite error code is returned.
+*/
+static int fts3AllocateSegdirIdx(Fts3Table *p, int iLevel, int *piIdx){
+  int rc;                         /* Return Code */
+  sqlite3_stmt *pNextIdx;         /* Query for next idx at level iLevel */
+  int iNext;                      /* Result of query pNextIdx */
+
+  /* Set variable iNext to the next available segdir index at level iLevel. */
+  rc = fts3SqlStmt(p, SQL_NEXT_SEGMENT_INDEX, &pNextIdx, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int(pNextIdx, 1, iLevel);
+    if( SQLITE_ROW==sqlite3_step(pNextIdx) ){
+      iNext = sqlite3_column_int64(pNextIdx, 0);
+    }
+    rc = sqlite3_reset(pNextIdx);
+  }
+
+  if( rc==SQLITE_OK ){
+    /* If iNext is FTS3_MERGE_COUNT, indicating that level iLevel is already
+    ** full, merge all segments in level iLevel into a single iLevel+1
+    ** segment and allocate (newly freed) index 0 at level iLevel. Otherwise,
+    ** if iNext is less than FTS3_MERGE_COUNT, allocate index iNext.
+    */
+    if( iNext>=FTS3_MERGE_COUNT ){
+      rc = fts3SegmentMerge(p, iLevel);
+      *piIdx = 0;
+    }else{
+      *piIdx = iNext;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Move the iterator passed as the first argument to the next term in the
+** segment. If successful, SQLITE_OK is returned. If there is no next term,
+** SQLITE_DONE. Otherwise, an SQLite error code.
+*/
+static int fts3SegReaderNext(Fts3SegReader *pReader){
+  char *pNext;                    /* Cursor variable */
+  int nPrefix;                    /* Number of bytes in term prefix */
+  int nSuffix;                    /* Number of bytes in term suffix */
+
+  if( !pReader->aDoclist ){
+    pNext = pReader->aNode;
+  }else{
+    pNext = &pReader->aDoclist[pReader->nDoclist];
+  }
+
+  if( !pNext || pNext>=&pReader->aNode[pReader->nNode] ){
+    int rc;
+    if( !pReader->pStmt ){
+      pReader->aNode = 0;
+      return SQLITE_OK;
+    }
+    rc = sqlite3_step(pReader->pStmt);
+    if( rc!=SQLITE_ROW ){
+      pReader->aNode = 0;
+      return (rc==SQLITE_DONE ? SQLITE_OK : rc);
+    }
+    pReader->nNode = sqlite3_column_bytes(pReader->pStmt, 0);
+    pReader->aNode = (char *)sqlite3_column_blob(pReader->pStmt, 0);
+    pNext = pReader->aNode;
+  }
+
+  pNext += sqlite3Fts3GetVarint32(pNext, &nPrefix);
+  pNext += sqlite3Fts3GetVarint32(pNext, &nSuffix);
+
+  if( nPrefix+nSuffix>pReader->nTermAlloc ){
+    int nNew = (nPrefix+nSuffix)*2;
+    char *zNew = sqlite3_realloc(pReader->zTerm, nNew);
+    if( !zNew ){
+      return SQLITE_NOMEM;
+    }
+    pReader->zTerm = zNew;
+    pReader->nTermAlloc = nNew;
+  }
+  memcpy(&pReader->zTerm[nPrefix], pNext, nSuffix);
+  pReader->nTerm = nPrefix+nSuffix;
+  pNext += nSuffix;
+  pNext += sqlite3Fts3GetVarint32(pNext, &pReader->nDoclist);
+  assert( pNext<&pReader->aNode[pReader->nNode] );
+  pReader->aDoclist = pNext;
+  pReader->pOffsetList = 0;
+  return SQLITE_OK;
+}
+
+/*
+** Set the SegReader to point to the first docid in the doclist associated
+** with the current term.
+*/
+static void fts3SegReaderFirstDocid(Fts3SegReader *pReader){
+  int n;
+  assert( pReader->aDoclist );
+  assert( !pReader->pOffsetList );
+  n = sqlite3Fts3GetVarint(pReader->aDoclist, &pReader->iDocid);
+  pReader->pOffsetList = &pReader->aDoclist[n];
+}
+
+/*
+** Advance the SegReader to point to the next docid in the doclist
+** associated with the current term.
+**
+** If arguments ppOffsetList and pnOffsetList are not NULL, then
+** *ppOffsetList is set to point to the first column-offset list
+** in the doclist entry (i.e. immediately past the docid varint).
+** *pnOffsetList is set to the length of the set of column-offset
+** lists, not including the nul-terminator byte. For example:
+*/
+static void fts3SegReaderNextDocid(
+  Fts3SegReader *pReader,
+  char **ppOffsetList,
+  int *pnOffsetList
+){
+  char *p = pReader->pOffsetList;
+  char c = 0;
+
+  /* Pointer p currently points at the first byte of an offset list. The
+  ** following two lines advance it to point one byte past the end of
+  ** the same offset list.
+  */
+  while( *p | c ) c = *p++ & 0x80;
+  p++;
+
+  /* If required, populate the output variables with a pointer to and the
+  ** size of the previous offset-list.
+  */
+  if( ppOffsetList ){
+    *ppOffsetList = pReader->pOffsetList;
+    *pnOffsetList = p - pReader->pOffsetList - 1;
+  }
+
+  /* If there are no more entries in the doclist, set pOffsetList to
+  ** NULL. Otherwise, set Fts3SegReader.iDocid to the next docid and
+  ** Fts3SegReader.pOffsetList to point to the next offset list before
+  ** returning.
+  */
+  if( p>=&pReader->aDoclist[pReader->nDoclist] ){
+    pReader->pOffsetList = 0;
+  }else{
+    sqlite3_int64 iDelta;
+    pReader->pOffsetList = p + sqlite3Fts3GetVarint(p, &iDelta);
+    pReader->iDocid += iDelta;
+  }
+}
+
+/*
+** Free all allocations associated with the iterator passed as the
+** second argument.
+*/
+SQLITE_PRIVATE void sqlite3Fts3SegReaderFree(Fts3Table *p, Fts3SegReader *pReader){
+  if( pReader ){
+    if( pReader->pStmt ){
+      /* Move the leaf-range SELECT statement to the aLeavesStmt[] array,
+      ** so that it can be reused when required by another query.
+      */
+      assert( p->nLeavesStmt<p->nLeavesTotal );
+      sqlite3_reset(pReader->pStmt);
+      p->aLeavesStmt[p->nLeavesStmt++] = pReader->pStmt;
+    }
+    sqlite3_free(pReader->zTerm);
+    sqlite3_free(pReader);
+  }
+}
+
+/*
+** Allocate a new SegReader object.
+*/
+SQLITE_PRIVATE int sqlite3Fts3SegReaderNew(
+  Fts3Table *p,                   /* Virtual table handle */
+  int iAge,                       /* Segment "age". */
+  sqlite3_int64 iStartLeaf,       /* First leaf to traverse */
+  sqlite3_int64 iEndLeaf,         /* Final leaf to traverse */
+  sqlite3_int64 iEndBlock,        /* Final block of segment */
+  const char *zRoot,              /* Buffer containing root node */
+  int nRoot,                      /* Size of buffer containing root node */
+  Fts3SegReader **ppReader        /* OUT: Allocated Fts3SegReader */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  Fts3SegReader *pReader;         /* Newly allocated SegReader object */
+  int nExtra = 0;                 /* Bytes to allocate segment root node */
+
+  if( iStartLeaf==0 ){
+    nExtra = nRoot;
+  }
+
+  pReader = (Fts3SegReader *)sqlite3_malloc(sizeof(Fts3SegReader) + nExtra);
+  if( !pReader ){
+    return SQLITE_NOMEM;
+  }
+  memset(pReader, 0, sizeof(Fts3SegReader));
+  pReader->iStartBlock = iStartLeaf;
+  pReader->iIdx = iAge;
+  pReader->iEndBlock = iEndBlock;
+
+  if( nExtra ){
+    /* The entire segment is stored in the root node. */
+    pReader->aNode = (char *)&pReader[1];
+    pReader->nNode = nRoot;
+    memcpy(pReader->aNode, zRoot, nRoot);
+  }else{
+    sqlite3_stmt *pStmt;
+
+    /* If the text of the SQL statement to iterate through a contiguous
+    ** set of entries in the %_segments table has not yet been composed,
+    ** compose it now.
+    */
+    if( !p->zSelectLeaves ){
+      p->zSelectLeaves = sqlite3_mprintf(
+          "SELECT block FROM %Q.'%q_segments' WHERE blockid BETWEEN ? AND ? "
+          "ORDER BY blockid", p->zDb, p->zName
+      );
+      if( !p->zSelectLeaves ){
+        rc = SQLITE_NOMEM;
+        goto finished;
+      }
+    }
+
+    /* If there are no free statements in the aLeavesStmt[] array, prepare
+    ** a new statement now. Otherwise, reuse a prepared statement from
+    ** aLeavesStmt[].
+    */
+    if( p->nLeavesStmt==0 ){
+      if( p->nLeavesTotal==p->nLeavesAlloc ){
+        int nNew = p->nLeavesAlloc + 16;
+        sqlite3_stmt **aNew = (sqlite3_stmt **)sqlite3_realloc(
+            p->aLeavesStmt, nNew*sizeof(sqlite3_stmt *)
+        );
+        if( !aNew ){
+          rc = SQLITE_NOMEM;
+          goto finished;
+        }
+        p->nLeavesAlloc = nNew;
+        p->aLeavesStmt = aNew;
+      }
+      rc = sqlite3_prepare_v2(p->db, p->zSelectLeaves, -1, &pReader->pStmt, 0);
+      if( rc!=SQLITE_OK ){
+        goto finished;
+      }
+      p->nLeavesTotal++;
+    }else{
+      pReader->pStmt = p->aLeavesStmt[--p->nLeavesStmt];
+    }
+
+    /* Bind the start and end leaf blockids to the prepared SQL statement. */
+    sqlite3_bind_int64(pReader->pStmt, 1, iStartLeaf);
+    sqlite3_bind_int64(pReader->pStmt, 2, iEndLeaf);
+  }
+  rc = fts3SegReaderNext(pReader);
+
+ finished:
+  if( rc==SQLITE_OK ){
+    *ppReader = pReader;
+  }else{
+    sqlite3Fts3SegReaderFree(p, pReader);
+  }
+  return rc;
+}
+
+
+/*
+** The second argument to this function is expected to be a statement of
+** the form:
+**
+**   SELECT
+**     idx,                  -- col 0
+**     start_block,          -- col 1
+**     leaves_end_block,     -- col 2
+**     end_block,            -- col 3
+**     root                  -- col 4
+**   FROM %_segdir ...
+**
+** This function allocates and initializes a Fts3SegReader structure to
+** iterate through the terms stored in the segment identified by the
+** current row that pStmt is pointing to.
+**
+** If successful, the Fts3SegReader is left pointing to the first term
+** in the segment and SQLITE_OK is returned. Otherwise, an SQLite error
+** code is returned.
+*/
+static int fts3SegReaderNew(
+  Fts3Table *p,                   /* Virtual table handle */
+  sqlite3_stmt *pStmt,            /* See above */
+  int iAge,                       /* Segment "age". */
+  Fts3SegReader **ppReader        /* OUT: Allocated Fts3SegReader */
+){
+  return sqlite3Fts3SegReaderNew(p, iAge,
+      sqlite3_column_int64(pStmt, 1),
+      sqlite3_column_int64(pStmt, 2),
+      sqlite3_column_int64(pStmt, 3),
+      sqlite3_column_blob(pStmt, 4),
+      sqlite3_column_bytes(pStmt, 4),
+      ppReader
+  );
+}
+
+/*
+** Compare the entries pointed to by two Fts3SegReader structures.
+** Comparison is as follows:
+**
+**   1) EOF is greater than not EOF.
+**
+**   2) The current terms (if any) are compared with memcmp(). If one
+**      term is a prefix of another, the longer term is considered the
+**      larger.
+**
+**   3) By segment age. An older segment is considered larger.
+*/
+static int fts3SegReaderCmp(Fts3SegReader *pLhs, Fts3SegReader *pRhs){
+  int rc;
+  if( pLhs->aNode && pRhs->aNode ){
+    int rc2 = pLhs->nTerm - pRhs->nTerm;
+    if( rc2<0 ){
+      rc = memcmp(pLhs->zTerm, pRhs->zTerm, pLhs->nTerm);
+    }else{
+      rc = memcmp(pLhs->zTerm, pRhs->zTerm, pRhs->nTerm);
+    }
+    if( rc==0 ){
+      rc = rc2;
+    }
+  }else{
+    rc = (pLhs->aNode==0) - (pRhs->aNode==0);
+  }
+  if( rc==0 ){
+    rc = pRhs->iIdx - pLhs->iIdx;
+  }
+  assert( rc!=0 );
+  return rc;
+}
+
+/*
+** A different comparison function for SegReader structures. In this
+** version, it is assumed that each SegReader points to an entry in
+** a doclist for identical terms. Comparison is made as follows:
+**
+**   1) EOF (end of doclist in this case) is greater than not EOF.
+**
+**   2) By current docid.
+**
+**   3) By segment age. An older segment is considered larger.
+*/
+static int fts3SegReaderDoclistCmp(Fts3SegReader *pLhs, Fts3SegReader *pRhs){
+  int rc = (pLhs->pOffsetList==0)-(pRhs->pOffsetList==0);
+  if( rc==0 ){
+    if( pLhs->iDocid==pRhs->iDocid ){
+      rc = pRhs->iIdx - pLhs->iIdx;
+    }else{
+      rc = (pLhs->iDocid > pRhs->iDocid) ? 1 : -1;
+    }
+  }
+  assert( pLhs->aNode && pRhs->aNode );
+  return rc;
+}
+
+/*
+** Compare the term that the Fts3SegReader object passed as the first argument
+** points to with the term specified by arguments zTerm and nTerm.
+**
+** If the pSeg iterator is already at EOF, return 0. Otherwise, return
+** -ve if the pSeg term is less than zTerm/nTerm, 0 if the two terms are
+** equal, or +ve if the pSeg term is greater than zTerm/nTerm.
+*/
+static int fts3SegReaderTermCmp(
+  Fts3SegReader *pSeg,            /* Segment reader object */
+  const char *zTerm,              /* Term to compare to */
+  int nTerm                       /* Size of term zTerm in bytes */
+){
+  int res = 0;
+  if( pSeg->aNode ){
+    if( pSeg->nTerm>nTerm ){
+      res = memcmp(pSeg->zTerm, zTerm, nTerm);
+    }else{
+      res = memcmp(pSeg->zTerm, zTerm, pSeg->nTerm);
+    }
+    if( res==0 ){
+      res = pSeg->nTerm-nTerm;
+    }
+  }
+  return res;
+}
+
+/*
+** Argument apSegment is an array of nSegment elements. It is known that
+** the final (nSegment-nSuspect) members are already in sorted order
+** (according to the comparison function provided). This function shuffles
+** the array around until all entries are in sorted order.
+*/
+static void fts3SegReaderSort(
+  Fts3SegReader **apSegment,                     /* Array to sort entries of */
+  int nSegment,                                  /* Size of apSegment array */
+  int nSuspect,                                  /* Unsorted entry count */
+  int (*xCmp)(Fts3SegReader *, Fts3SegReader *)  /* Comparison function */
+){
+  int i;                          /* Iterator variable */
+
+  assert( nSuspect<=nSegment );
+
+  if( nSuspect==nSegment ) nSuspect--;
+  for(i=nSuspect-1; i>=0; i--){
+    int j;
+    for(j=i; j<(nSegment-1); j++){
+      Fts3SegReader *pTmp;
+      if( xCmp(apSegment[j], apSegment[j+1])<0 ) break;
+      pTmp = apSegment[j+1];
+      apSegment[j+1] = apSegment[j];
+      apSegment[j] = pTmp;
+    }
+  }
+
+#ifndef NDEBUG
+  /* Check that the list really is sorted now. */
+  for(i=0; i<(nSuspect-1); i++){
+    assert( xCmp(apSegment[i], apSegment[i+1])<0 );
+  }
+#endif
+}
+
+/*
+** Insert a record into the %_segments table.
+*/
+static int fts3WriteSegment(
+  Fts3Table *p,                   /* Virtual table handle */
+  sqlite3_int64 iBlock,           /* Block id for new block */
+  char *z,                        /* Pointer to buffer containing block data */
+  int n                           /* Size of buffer z in bytes */
+){
+  sqlite3_stmt *pStmt;
+  int rc = fts3SqlStmt(p, SQL_INSERT_SEGMENTS, &pStmt, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pStmt, 1, iBlock);
+    rc = sqlite3_bind_blob(pStmt, 2, z, n, SQLITE_STATIC);
+    if( rc==SQLITE_OK ){
+      sqlite3_step(pStmt);
+      rc = sqlite3_reset(pStmt);
+    }
+  }
+  return rc;
+}
+
+/*
+** Insert a record into the %_segdir table.
+*/
+static int fts3WriteSegdir(
+  Fts3Table *p,                   /* Virtual table handle */
+  int iLevel,                     /* Value for "level" field */
+  int iIdx,                       /* Value for "idx" field */
+  sqlite3_int64 iStartBlock,      /* Value for "start_block" field */
+  sqlite3_int64 iLeafEndBlock,    /* Value for "leaves_end_block" field */
+  sqlite3_int64 iEndBlock,        /* Value for "end_block" field */
+  char *zRoot,                    /* Blob value for "root" field */
+  int nRoot                       /* Number of bytes in buffer zRoot */
+){
+  sqlite3_stmt *pStmt;
+  int rc = fts3SqlStmt(p, SQL_INSERT_SEGDIR, &pStmt, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int(pStmt, 1, iLevel);
+    sqlite3_bind_int(pStmt, 2, iIdx);
+    sqlite3_bind_int64(pStmt, 3, iStartBlock);
+    sqlite3_bind_int64(pStmt, 4, iLeafEndBlock);
+    sqlite3_bind_int64(pStmt, 5, iEndBlock);
+    rc = sqlite3_bind_blob(pStmt, 6, zRoot, nRoot, SQLITE_STATIC);
+    if( rc==SQLITE_OK ){
+      sqlite3_step(pStmt);
+      rc = sqlite3_reset(pStmt);
+    }
+  }
+  return rc;
+}
+
+/*
+** Return the size of the common prefix (if any) shared by zPrev and
+** zNext, in bytes. For example,
+**
+**   fts3PrefixCompress("abc", 3, "abcdef", 6)   // returns 3
+**   fts3PrefixCompress("abX", 3, "abcdef", 6)   // returns 2
+**   fts3PrefixCompress("abX", 3, "Xbcdef", 6)   // returns 0
+*/
+static int fts3PrefixCompress(
+  const char *zPrev,              /* Buffer containing previous term */
+  int nPrev,                      /* Size of buffer zPrev in bytes */
+  const char *zNext,              /* Buffer containing next term */
+  int nNext                       /* Size of buffer zNext in bytes */
+){
+  int n;
+  for(n=0; n<nPrev && zPrev[n]==zNext[n]; n++);
+  return n;
+}
+
+/*
+** Add term zTerm to the SegmentNode. It is guaranteed that zTerm is larger
+** (according to memcmp) than the previous term.
+*/
+static int fts3NodeAddTerm(
+  Fts3Table *p,               /* Virtual table handle */
+  SegmentNode **ppTree,           /* IN/OUT: SegmentNode handle */
+  int isCopyTerm,                 /* True if zTerm/nTerm is transient */
+  const char *zTerm,              /* Pointer to buffer containing term */
+  int nTerm                       /* Size of term in bytes */
+){
+  SegmentNode *pTree = *ppTree;
+  int rc;
+  SegmentNode *pNew;
+
+  /* First try to append the term to the current node. Return early if
+  ** this is possible.
+  */
+  if( pTree ){
+    int nData = pTree->nData;     /* Current size of node in bytes */
+    int nReq = nData;             /* Required space after adding zTerm */
+    int nPrefix;                  /* Number of bytes of prefix compression */
+    int nSuffix;                  /* Suffix length */
+
+    nPrefix = fts3PrefixCompress(pTree->zTerm, pTree->nTerm, zTerm, nTerm);
+    nSuffix = nTerm-nPrefix;
+
+    nReq += sqlite3Fts3VarintLen(nPrefix)+sqlite3Fts3VarintLen(nSuffix)+nSuffix;
+    if( nReq<=INTERIOR_MAX || !pTree->zTerm ){
+
+      if( nReq>INTERIOR_MAX ){
+        /* An unusual case: this is the first term to be added to the node
+        ** and the static node buffer (INTERIOR_MAX bytes) is not large
+        ** enough. Use a separately malloced buffer instead This wastes
+        ** INTERIOR_MAX bytes, but since this scenario only comes about when
+        ** the database contain two terms that share a prefix of almost 2KB,
+        ** this is not expected to be a serious problem.
+        */
+        assert( pTree->aData==(char *)&pTree[1] );
+        pTree->aData = (char *)sqlite3_malloc(nReq);
+        if( !pTree->aData ){
+          return SQLITE_NOMEM;
+        }
+      }
+
+      if( pTree->zTerm ){
+        /* There is no prefix-length field for first term in a node */
+        nData += sqlite3Fts3PutVarint(&pTree->aData[nData], nPrefix);
+      }
+
+      nData += sqlite3Fts3PutVarint(&pTree->aData[nData], nSuffix);
+      memcpy(&pTree->aData[nData], &zTerm[nPrefix], nSuffix);
+      pTree->nData = nData + nSuffix;
+      pTree->nEntry++;
+
+      if( isCopyTerm ){
+        if( pTree->nMalloc<nTerm ){
+          char *zNew = sqlite3_realloc(pTree->zMalloc, nTerm*2);
+          if( !zNew ){
+            return SQLITE_NOMEM;
+          }
+          pTree->nMalloc = nTerm*2;
+          pTree->zMalloc = zNew;
+        }
+        pTree->zTerm = pTree->zMalloc;
+        memcpy(pTree->zTerm, zTerm, nTerm);
+        pTree->nTerm = nTerm;
+      }else{
+        pTree->zTerm = (char *)zTerm;
+        pTree->nTerm = nTerm;
+      }
+      return SQLITE_OK;
+    }
+  }
+
+  /* If control flows to here, it was not possible to append zTerm to the
+  ** current node. Create a new node (a right-sibling of the current node).
+  ** If this is the first node in the tree, the term is added to it.
+  **
+  ** Otherwise, the term is not added to the new node, it is left empty for
+  ** now. Instead, the term is inserted into the parent of pTree. If pTree
+  ** has no parent, one is created here.
+  */
+  pNew = (SegmentNode *)sqlite3_malloc(sizeof(SegmentNode) + INTERIOR_MAX);
+  if( !pNew ){
+    return SQLITE_NOMEM;
+  }
+  memset(pNew, 0, sizeof(SegmentNode));
+  pNew->nData = 1 + FTS3_VARINT_MAX;
+  pNew->aData = (char *)&pNew[1];
+
+  if( pTree ){
+    SegmentNode *pParent = pTree->pParent;
+    rc = fts3NodeAddTerm(p, &pParent, isCopyTerm, zTerm, nTerm);
+    if( pTree->pParent==0 ){
+      pTree->pParent = pParent;
+    }
+    pTree->pRight = pNew;
+    pNew->pLeftmost = pTree->pLeftmost;
+    pNew->pParent = pParent;
+    pNew->zMalloc = pTree->zMalloc;
+    pNew->nMalloc = pTree->nMalloc;
+    pTree->zMalloc = 0;
+  }else{
+    pNew->pLeftmost = pNew;
+    rc = fts3NodeAddTerm(p, &pNew, isCopyTerm, zTerm, nTerm);
+  }
+
+  *ppTree = pNew;
+  return rc;
+}
+
+/*
+** Helper function for fts3NodeWrite().
+*/
+static int fts3TreeFinishNode(
+  SegmentNode *pTree,
+  int iHeight,
+  sqlite3_int64 iLeftChild
+){
+  int nStart;
+  assert( iHeight>=1 && iHeight<128 );
+  nStart = FTS3_VARINT_MAX - sqlite3Fts3VarintLen(iLeftChild);
+  pTree->aData[nStart] = (char)iHeight;
+  sqlite3Fts3PutVarint(&pTree->aData[nStart+1], iLeftChild);
+  return nStart;
+}
+
+/*
+** Write the buffer for the segment node pTree and all of its peers to the
+** database. Then call this function recursively to write the parent of
+** pTree and its peers to the database.
+**
+** Except, if pTree is a root node, do not write it to the database. Instead,
+** set output variables *paRoot and *pnRoot to contain the root node.
+**
+** If successful, SQLITE_OK is returned and output variable *piLast is
+** set to the largest blockid written to the database (or zero if no
+** blocks were written to the db). Otherwise, an SQLite error code is
+** returned.
+*/
+static int fts3NodeWrite(
+  Fts3Table *p,                   /* Virtual table handle */
+  SegmentNode *pTree,             /* SegmentNode handle */
+  int iHeight,                    /* Height of this node in tree */
+  sqlite3_int64 iLeaf,            /* Block id of first leaf node */
+  sqlite3_int64 iFree,            /* Block id of next free slot in %_segments */
+  sqlite3_int64 *piLast,          /* OUT: Block id of last entry written */
+  char **paRoot,                  /* OUT: Data for root node */
+  int *pnRoot                     /* OUT: Size of root node in bytes */
+){
+  int rc = SQLITE_OK;
+
+  if( !pTree->pParent ){
+    /* Root node of the tree. */
+    int nStart = fts3TreeFinishNode(pTree, iHeight, iLeaf);
+    *piLast = iFree-1;
+    *pnRoot = pTree->nData - nStart;
+    *paRoot = &pTree->aData[nStart];
+  }else{
+    SegmentNode *pIter;
+    sqlite3_int64 iNextFree = iFree;
+    sqlite3_int64 iNextLeaf = iLeaf;
+    for(pIter=pTree->pLeftmost; pIter && rc==SQLITE_OK; pIter=pIter->pRight){
+      int nStart = fts3TreeFinishNode(pIter, iHeight, iNextLeaf);
+      int nWrite = pIter->nData - nStart;
+
+      rc = fts3WriteSegment(p, iNextFree, &pIter->aData[nStart], nWrite);
+      iNextFree++;
+      iNextLeaf += (pIter->nEntry+1);
+    }
+    if( rc==SQLITE_OK ){
+      assert( iNextLeaf==iFree );
+      rc = fts3NodeWrite(
+          p, pTree->pParent, iHeight+1, iFree, iNextFree, piLast, paRoot, pnRoot
+      );
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Free all memory allocations associated with the tree pTree.
+*/
+static void fts3NodeFree(SegmentNode *pTree){
+  if( pTree ){
+    SegmentNode *p = pTree->pLeftmost;
+    fts3NodeFree(p->pParent);
+    while( p ){
+      SegmentNode *pRight = p->pRight;
+      if( p->aData!=(char *)&p[1] ){
+        sqlite3_free(p->aData);
+      }
+      assert( pRight==0 || p->zMalloc==0 );
+      sqlite3_free(p->zMalloc);
+      sqlite3_free(p);
+      p = pRight;
+    }
+  }
+}
+
+/*
+** Add a term to the segment being constructed by the SegmentWriter object
+** *ppWriter. When adding the first term to a segment, *ppWriter should
+** be passed NULL. This function will allocate a new SegmentWriter object
+** and return it via the input/output variable *ppWriter in this case.
+**
+** If successful, SQLITE_OK is returned. Otherwise, an SQLite error code.
+*/
+static int fts3SegWriterAdd(
+  Fts3Table *p,                   /* Virtual table handle */
+  SegmentWriter **ppWriter,       /* IN/OUT: SegmentWriter handle */
+  int isCopyTerm,                 /* True if buffer zTerm must be copied */
+  const char *zTerm,              /* Pointer to buffer containing term */
+  int nTerm,                      /* Size of term in bytes */
+  const char *aDoclist,           /* Pointer to buffer containing doclist */
+  int nDoclist                    /* Size of doclist in bytes */
+){
+  int nPrefix;                    /* Size of term prefix in bytes */
+  int nSuffix;                    /* Size of term suffix in bytes */
+  int nReq;                       /* Number of bytes required on leaf page */
+  int nData;
+  SegmentWriter *pWriter = *ppWriter;
+
+  if( !pWriter ){
+    int rc;
+    sqlite3_stmt *pStmt;
+
+    /* Allocate the SegmentWriter structure */
+    pWriter = (SegmentWriter *)sqlite3_malloc(sizeof(SegmentWriter));
+    if( !pWriter ) return SQLITE_NOMEM;
+    memset(pWriter, 0, sizeof(SegmentWriter));
+    *ppWriter = pWriter;
+
+    /* Allocate a buffer in which to accumulate data */
+    pWriter->aData = (char *)sqlite3_malloc(LEAF_MAX);
+    if( !pWriter->aData ) return SQLITE_NOMEM;
+    pWriter->nSize = LEAF_MAX;
+
+    /* Find the next free blockid in the %_segments table */
+    rc = fts3SqlStmt(p, SQL_NEXT_SEGMENTS_ID, &pStmt, 0);
+    if( rc!=SQLITE_OK ) return rc;
+    if( SQLITE_ROW==sqlite3_step(pStmt) ){
+      pWriter->iFree = sqlite3_column_int64(pStmt, 0);
+      pWriter->iFirst = pWriter->iFree;
+    }
+    rc = sqlite3_reset(pStmt);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+  nData = pWriter->nData;
+
+  nPrefix = fts3PrefixCompress(pWriter->zTerm, pWriter->nTerm, zTerm, nTerm);
+  nSuffix = nTerm-nPrefix;
+
+  /* Figure out how many bytes are required by this new entry */
+  nReq = sqlite3Fts3VarintLen(nPrefix) +    /* varint containing prefix size */
+    sqlite3Fts3VarintLen(nSuffix) +         /* varint containing suffix size */
+    nSuffix +                               /* Term suffix */
+    sqlite3Fts3VarintLen(nDoclist) +        /* Size of doclist */
+    nDoclist;                               /* Doclist data */
+
+  if( nData>0 && nData+nReq>LEAF_MAX ){
+    int rc;
+
+    /* The current leaf node is full. Write it out to the database. */
+    rc = fts3WriteSegment(p, pWriter->iFree++, pWriter->aData, nData);
+    if( rc!=SQLITE_OK ) return rc;
+
+    /* Add the current term to the interior node tree. The term added to
+    ** the interior tree must:
+    **
+    **   a) be greater than the largest term on the leaf node just written
+    **      to the database (still available in pWriter->zTerm), and
+    **
+    **   b) be less than or equal to the term about to be added to the new
+    **      leaf node (zTerm/nTerm).
+    **
+    ** In other words, it must be the prefix of zTerm 1 byte longer than
+    ** the common prefix (if any) of zTerm and pWriter->zTerm.
+    */
+    assert( nPrefix<nTerm );
+    rc = fts3NodeAddTerm(p, &pWriter->pTree, isCopyTerm, zTerm, nPrefix+1);
+    if( rc!=SQLITE_OK ) return rc;
+
+    nData = 0;
+    pWriter->nTerm = 0;
+
+    nPrefix = 0;
+    nSuffix = nTerm;
+    nReq = 1 +                              /* varint containing prefix size */
+      sqlite3Fts3VarintLen(nTerm) +         /* varint containing suffix size */
+      nTerm +                               /* Term suffix */
+      sqlite3Fts3VarintLen(nDoclist) +      /* Size of doclist */
+      nDoclist;                             /* Doclist data */
+  }
+
+  /* If the buffer currently allocated is too small for this entry, realloc
+  ** the buffer to make it large enough.
+  */
+  if( nReq>pWriter->nSize ){
+    char *aNew = sqlite3_realloc(pWriter->aData, nReq);
+    if( !aNew ) return SQLITE_NOMEM;
+    pWriter->aData = aNew;
+    pWriter->nSize = nReq;
+  }
+  assert( nData+nReq<=pWriter->nSize );
+
+  /* Append the prefix-compressed term and doclist to the buffer. */
+  nData += sqlite3Fts3PutVarint(&pWriter->aData[nData], nPrefix);
+  nData += sqlite3Fts3PutVarint(&pWriter->aData[nData], nSuffix);
+  memcpy(&pWriter->aData[nData], &zTerm[nPrefix], nSuffix);
+  nData += nSuffix;
+  nData += sqlite3Fts3PutVarint(&pWriter->aData[nData], nDoclist);
+  memcpy(&pWriter->aData[nData], aDoclist, nDoclist);
+  pWriter->nData = nData + nDoclist;
+
+  /* Save the current term so that it can be used to prefix-compress the next.
+  ** If the isCopyTerm parameter is true, then the buffer pointed to by
+  ** zTerm is transient, so take a copy of the term data. Otherwise, just
+  ** store a copy of the pointer.
+  */
+  if( isCopyTerm ){
+    if( nTerm>pWriter->nMalloc ){
+      char *zNew = sqlite3_realloc(pWriter->zMalloc, nTerm*2);
+      if( !zNew ){
+        return SQLITE_NOMEM;
+      }
+      pWriter->nMalloc = nTerm*2;
+      pWriter->zMalloc = zNew;
+      pWriter->zTerm = zNew;
+    }
+    assert( pWriter->zTerm==pWriter->zMalloc );
+    memcpy(pWriter->zTerm, zTerm, nTerm);
+  }else{
+    pWriter->zTerm = (char *)zTerm;
+  }
+  pWriter->nTerm = nTerm;
+
+  return SQLITE_OK;
+}
+
+/*
+** Flush all data associated with the SegmentWriter object pWriter to the
+** database. This function must be called after all terms have been added
+** to the segment using fts3SegWriterAdd(). If successful, SQLITE_OK is
+** returned. Otherwise, an SQLite error code.
+*/
+static int fts3SegWriterFlush(
+  Fts3Table *p,                   /* Virtual table handle */
+  SegmentWriter *pWriter,         /* SegmentWriter to flush to the db */
+  int iLevel,                     /* Value for 'level' column of %_segdir */
+  int iIdx                        /* Value for 'idx' column of %_segdir */
+){
+  int rc;                         /* Return code */
+  if( pWriter->pTree ){
+    sqlite3_int64 iLast;          /* Largest block id written to database */
+    sqlite3_int64 iLastLeaf;      /* Largest leaf block id written to db */
+    char *zRoot;                  /* Pointer to buffer containing root node */
+    int nRoot;                    /* Size of buffer zRoot */
+
+    iLastLeaf = pWriter->iFree;
+    rc = fts3WriteSegment(p, pWriter->iFree++, pWriter->aData, pWriter->nData);
+    if( rc==SQLITE_OK ){
+      rc = fts3NodeWrite(p, pWriter->pTree, 1,
+          pWriter->iFirst, pWriter->iFree, &iLast, &zRoot, &nRoot);
+    }
+    if( rc==SQLITE_OK ){
+      rc = fts3WriteSegdir(
+          p, iLevel, iIdx, pWriter->iFirst, iLastLeaf, iLast, zRoot, nRoot);
+    }
+  }else{
+    /* The entire tree fits on the root node. Write it to the segdir table. */
+    rc = fts3WriteSegdir(
+        p, iLevel, iIdx, 0, 0, 0, pWriter->aData, pWriter->nData);
+  }
+  return rc;
+}
+
+/*
+** Release all memory held by the SegmentWriter object passed as the
+** first argument.
+*/
+static void fts3SegWriterFree(SegmentWriter *pWriter){
+  if( pWriter ){
+    sqlite3_free(pWriter->aData);
+    sqlite3_free(pWriter->zMalloc);
+    fts3NodeFree(pWriter->pTree);
+    sqlite3_free(pWriter);
+  }
+}
+
+/*
+** The first value in the apVal[] array is assumed to contain an integer.
+** This function tests if there exist any documents with docid values that
+** are different from that integer. i.e. if deleting the document with docid
+** apVal[0] would mean the FTS3 table were empty.
+**
+** If successful, *pisEmpty is set to true if the table is empty except for
+** document apVal[0], or false otherwise, and SQLITE_OK is returned. If an
+** error occurs, an SQLite error code is returned.
+*/
+static int fts3IsEmpty(Fts3Table *p, sqlite3_value **apVal, int *pisEmpty){
+  sqlite3_stmt *pStmt;
+  int rc;
+  rc = fts3SqlStmt(p, SQL_IS_EMPTY, &pStmt, apVal);
+  if( rc==SQLITE_OK ){
+    if( SQLITE_ROW==sqlite3_step(pStmt) ){
+      *pisEmpty = sqlite3_column_int(pStmt, 0);
+    }
+    rc = sqlite3_reset(pStmt);
+  }
+  return rc;
+}
+
+/*
+** Set *pnSegment to the number of segments of level iLevel in the database.
+**
+** Return SQLITE_OK if successful, or an SQLite error code if not.
+*/
+static int fts3SegmentCount(Fts3Table *p, int iLevel, int *pnSegment){
+  sqlite3_stmt *pStmt;
+  int rc;
+
+  assert( iLevel>=0 );
+  rc = fts3SqlStmt(p, SQL_SELECT_LEVEL_COUNT, &pStmt, 0);
+  if( rc!=SQLITE_OK ) return rc;
+  sqlite3_bind_int(pStmt, 1, iLevel);
+  if( SQLITE_ROW==sqlite3_step(pStmt) ){
+    *pnSegment = sqlite3_column_int(pStmt, 0);
+  }
+  return sqlite3_reset(pStmt);
+}
+
+/*
+** Set *pnSegment to the total number of segments in the database. Set
+** *pnMax to the largest segment level in the database (segment levels
+** are stored in the 'level' column of the %_segdir table).
+**
+** Return SQLITE_OK if successful, or an SQLite error code if not.
+*/
+static int fts3SegmentCountMax(Fts3Table *p, int *pnSegment, int *pnMax){
+  sqlite3_stmt *pStmt;
+  int rc;
+
+  rc = fts3SqlStmt(p, SQL_SELECT_SEGDIR_COUNT_MAX, &pStmt, 0);
+  if( rc!=SQLITE_OK ) return rc;
+  if( SQLITE_ROW==sqlite3_step(pStmt) ){
+    *pnSegment = sqlite3_column_int(pStmt, 0);
+    *pnMax = sqlite3_column_int(pStmt, 1);
+  }
+  return sqlite3_reset(pStmt);
+}
+
+/*
+** This function is used after merging multiple segments into a single large
+** segment to delete the old, now redundant, segment b-trees. Specifically,
+** it:
+**
+**   1) Deletes all %_segments entries for the segments associated with
+**      each of the SegReader objects in the array passed as the third
+**      argument, and
+**
+**   2) deletes all %_segdir entries with level iLevel, or all %_segdir
+**      entries regardless of level if (iLevel<0).
+**
+** SQLITE_OK is returned if successful, otherwise an SQLite error code.
+*/
+static int fts3DeleteSegdir(
+  Fts3Table *p,                   /* Virtual table handle */
+  int iLevel,                     /* Level of %_segdir entries to delete */
+  Fts3SegReader **apSegment,      /* Array of SegReader objects */
+  int nReader                     /* Size of array apSegment */
+){
+  int rc;                         /* Return Code */
+  int i;                          /* Iterator variable */
+  sqlite3_stmt *pDelete;          /* SQL statement to delete rows */
+
+  rc = fts3SqlStmt(p, SQL_DELETE_SEGMENTS_RANGE, &pDelete, 0);
+  for(i=0; rc==SQLITE_OK && i<nReader; i++){
+    Fts3SegReader *pSegment = apSegment[i];
+    if( pSegment->iStartBlock ){
+      sqlite3_bind_int64(pDelete, 1, pSegment->iStartBlock);
+      sqlite3_bind_int64(pDelete, 2, pSegment->iEndBlock);
+      sqlite3_step(pDelete);
+      rc = sqlite3_reset(pDelete);
+    }
+  }
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  if( iLevel>=0 ){
+    rc = fts3SqlStmt(p, SQL_DELETE_SEGDIR_BY_LEVEL, &pDelete, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int(pDelete, 1, iLevel);
+      sqlite3_step(pDelete);
+      rc = sqlite3_reset(pDelete);
+    }
+  }else{
+    rc = fts3SqlExec(p, SQL_DELETE_ALL_SEGDIR, 0);
+  }
+
+  return rc;
+}
+
+/*
+** When this function is called, buffer *ppList (size *pnList bytes) contains
+** a position list that may (or may not) feature multiple columns. This
+** function adjusts the pointer *ppList and the length *pnList so that they
+** identify the subset of the position list that corresponds to column iCol.
+**
+** If there are no entries in the input position list for column iCol, then
+** *pnList is set to zero before returning.
+*/
+static void fts3ColumnFilter(
+  int iCol,                       /* Column to filter on */
+  char **ppList,                  /* IN/OUT: Pointer to position list */
+  int *pnList                     /* IN/OUT: Size of buffer *ppList in bytes */
+){
+  char *pList = *ppList;
+  int nList = *pnList;
+  char *pEnd = &pList[nList];
+  int iCurrent = 0;
+  char *p = pList;
+
+  assert( iCol>=0 );
+  while( 1 ){
+    char c = 0;
+    while( p<pEnd && (c | *p)&0xFE ) c = *p++ & 0x80;
+
+    if( iCol==iCurrent ){
+      nList = (p - pList);
+      break;
+    }
+
+    nList -= (p - pList);
+    pList = p;
+    if( nList==0 ){
+      break;
+    }
+    p = &pList[1];
+    p += sqlite3Fts3GetVarint32(p, &iCurrent);
+  }
+
+  *ppList = pList;
+  *pnList = nList;
+}
+
+/*
+** sqlite3Fts3SegReaderIterate() callback used when merging multiple
+** segments to create a single, larger segment.
+*/
+static int fts3MergeCallback(
+  Fts3Table *p,
+  void *pContext,
+  char *zTerm,
+  int nTerm,
+  char *aDoclist,
+  int nDoclist
+){
+  SegmentWriter **ppW = (SegmentWriter **)pContext;
+  return fts3SegWriterAdd(p, ppW, 1, zTerm, nTerm, aDoclist, nDoclist);
+}
+
+/*
+** This function is used to iterate through a contiguous set of terms
+** stored in the full-text index. It merges data contained in one or
+** more segments to support this.
+**
+** The second argument is passed an array of pointers to SegReader objects
+** allocated with sqlite3Fts3SegReaderNew(). This function merges the range
+** of terms selected by each SegReader. If a single term is present in
+** more than one segment, the associated doclists are merged. For each
+** term and (possibly merged) doclist in the merged range, the callback
+** function xFunc is invoked with its arguments set as follows.
+**
+**   arg 0: Copy of 'p' parameter passed to this function
+**   arg 1: Copy of 'pContext' parameter passed to this function
+**   arg 2: Pointer to buffer containing term
+**   arg 3: Size of arg 2 buffer in bytes
+**   arg 4: Pointer to buffer containing doclist
+**   arg 5: Size of arg 2 buffer in bytes
+**
+** The 4th argument to this function is a pointer to a structure of type
+** Fts3SegFilter, defined in fts3Int.h. The contents of this structure
+** further restrict the range of terms that callbacks are made for and
+** modify the behaviour of this function. See comments above structure
+** definition for details.
+*/
+SQLITE_PRIVATE int sqlite3Fts3SegReaderIterate(
+  Fts3Table *p,                   /* Virtual table handle */
+  Fts3SegReader **apSegment,      /* Array of Fts3SegReader objects */
+  int nSegment,                   /* Size of apSegment array */
+  Fts3SegFilter *pFilter,         /* Restrictions on range of iteration */
+  int (*xFunc)(Fts3Table *, void *, char *, int, char *, int),  /* Callback */
+  void *pContext                  /* Callback context (2nd argument) */
+){
+  int i;                          /* Iterator variable */
+  char *aBuffer = 0;              /* Buffer to merge doclists in */
+  int nAlloc = 0;                 /* Allocated size of aBuffer buffer */
+  int rc = SQLITE_OK;             /* Return code */
+
+  int isIgnoreEmpty =  (pFilter->flags & FTS3_SEGMENT_IGNORE_EMPTY);
+  int isRequirePos =   (pFilter->flags & FTS3_SEGMENT_REQUIRE_POS);
+  int isColFilter =    (pFilter->flags & FTS3_SEGMENT_COLUMN_FILTER);
+  int isPrefix =       (pFilter->flags & FTS3_SEGMENT_PREFIX);
+
+  /* If the Fts3SegFilter defines a specific term (or term prefix) to search
+  ** for, then advance each segment iterator until it points to a term of
+  ** equal or greater value than the specified term. This prevents many
+  ** unnecessary merge/sort operations for the case where single segment
+  ** b-tree leaf nodes contain more than one term.
+  */
+  if( pFilter->zTerm ){
+    int nTerm = pFilter->nTerm;
+    const char *zTerm = pFilter->zTerm;
+    for(i=0; i<nSegment; i++){
+      Fts3SegReader *pSeg = apSegment[i];
+      while( fts3SegReaderTermCmp(pSeg, zTerm, nTerm)<0 ){
+        rc = fts3SegReaderNext(pSeg);
+        if( rc!=SQLITE_OK ) goto finished;
+      }
+    }
+  }
+
+  fts3SegReaderSort(apSegment, nSegment, nSegment, fts3SegReaderCmp);
+  while( apSegment[0]->aNode ){
+    int nTerm = apSegment[0]->nTerm;
+    char *zTerm = apSegment[0]->zTerm;
+    int nMerge = 1;
+
+    /* If this is a prefix-search, and if the term that apSegment[0] points
+    ** to does not share a suffix with pFilter->zTerm/nTerm, then all
+    ** required callbacks have been made. In this case exit early.
+    **
+    ** Similarly, if this is a search for an exact match, and the first term
+    ** of segment apSegment[0] is not a match, exit early.
+    */
+    if( pFilter->zTerm ){
+      if( nTerm<pFilter->nTerm
+       || (!isPrefix && nTerm>pFilter->nTerm)
+       || memcmp(zTerm, pFilter->zTerm, pFilter->nTerm)
+    ){
+        goto finished;
+      }
+    }
+
+    while( nMerge<nSegment
+        && apSegment[nMerge]->aNode
+        && apSegment[nMerge]->nTerm==nTerm
+        && 0==memcmp(zTerm, apSegment[nMerge]->zTerm, nTerm)
+    ){
+      nMerge++;
+    }
+
+    if( nMerge==1 && !isIgnoreEmpty && !isColFilter && isRequirePos ){
+      Fts3SegReader *p0 = apSegment[0];
+      rc = xFunc(p, pContext, zTerm, nTerm, p0->aDoclist, p0->nDoclist);
+      if( rc!=SQLITE_OK ) goto finished;
+    }else{
+      int nDoclist = 0;           /* Size of doclist */
+      sqlite3_int64 iPrev = 0;    /* Previous docid stored in doclist */
+
+      /* The current term of the first nMerge entries in the array
+      ** of Fts3SegReader objects is the same. The doclists must be merged
+      ** and a single term added to the new segment.
+      */
+      for(i=0; i<nMerge; i++){
+        fts3SegReaderFirstDocid(apSegment[i]);
+      }
+      fts3SegReaderSort(apSegment, nMerge, nMerge, fts3SegReaderDoclistCmp);
+      while( apSegment[0]->pOffsetList ){
+        int j;                    /* Number of segments that share a docid */
+        char *pList;
+        int nList;
+        int nByte;
+        sqlite3_int64 iDocid = apSegment[0]->iDocid;
+        fts3SegReaderNextDocid(apSegment[0], &pList, &nList);
+        j = 1;
+        while( j<nMerge
+            && apSegment[j]->pOffsetList
+            && apSegment[j]->iDocid==iDocid
+        ){
+          fts3SegReaderNextDocid(apSegment[j], 0, 0);
+          j++;
+        }
+
+        if( isColFilter ){
+          fts3ColumnFilter(pFilter->iCol, &pList, &nList);
+        }
+
+        if( !isIgnoreEmpty || nList>0 ){
+          nByte = sqlite3Fts3VarintLen(iDocid-iPrev) + (isRequirePos?nList+1:0);
+          if( nDoclist+nByte>nAlloc ){
+            char *aNew;
+            nAlloc = nDoclist+nByte*2;
+            aNew = sqlite3_realloc(aBuffer, nAlloc);
+            if( !aNew ){
+              rc = SQLITE_NOMEM;
+              goto finished;
+            }
+            aBuffer = aNew;
+          }
+          nDoclist += sqlite3Fts3PutVarint(&aBuffer[nDoclist], iDocid-iPrev);
+          iPrev = iDocid;
+          if( isRequirePos ){
+            memcpy(&aBuffer[nDoclist], pList, nList);
+            nDoclist += nList;
+            aBuffer[nDoclist++] = '\0';
+          }
+        }
+
+        fts3SegReaderSort(apSegment, nMerge, j, fts3SegReaderDoclistCmp);
+      }
+
+      if( nDoclist>0 ){
+        rc = xFunc(p, pContext, zTerm, nTerm, aBuffer, nDoclist);
+        if( rc!=SQLITE_OK ) goto finished;
+      }
+    }
+
+    /* If there is a term specified to filter on, and this is not a prefix
+    ** search, return now. The callback that corresponds to the required
+    ** term (if such a term exists in the index) has already been made.
+    */
+    if( pFilter->zTerm && !isPrefix ){
+      goto finished;
+    }
+
+    for(i=0; i<nMerge; i++){
+      rc = fts3SegReaderNext(apSegment[i]);
+      if( rc!=SQLITE_OK ) goto finished;
+    }
+    fts3SegReaderSort(apSegment, nSegment, nMerge, fts3SegReaderCmp);
+  }
+
+ finished:
+  sqlite3_free(aBuffer);
+  return rc;
+}
+
+/*
+** Merge all level iLevel segments in the database into a single
+** iLevel+1 segment. Or, if iLevel<0, merge all segments into a
+** single segment with a level equal to the numerically largest level
+** currently present in the database.
+**
+** If this function is called with iLevel<0, but there is only one
+** segment in the database, SQLITE_DONE is returned immediately.
+** Otherwise, if successful, SQLITE_OK is returned. If an error occurs,
+** an SQLite error code is returned.
+*/
+static int fts3SegmentMerge(Fts3Table *p, int iLevel){
+  int i;                          /* Iterator variable */
+  int rc;                         /* Return code */
+  int iIdx;                       /* Index of new segment */
+  int iNewLevel;                  /* Level to create new segment at */
+  sqlite3_stmt *pStmt;
+  SegmentWriter *pWriter = 0;
+  int nSegment = 0;               /* Number of segments being merged */
+  Fts3SegReader **apSegment = 0;  /* Array of Segment iterators */
+  Fts3SegFilter filter;           /* Segment term filter condition */
+
+  if( iLevel<0 ){
+    /* This call is to merge all segments in the database to a single
+    ** segment. The level of the new segment is equal to the the numerically
+    ** greatest segment level currently present in the database. The index
+    ** of the new segment is always 0.
+    */
+    iIdx = 0;
+    rc = fts3SegmentCountMax(p, &nSegment, &iNewLevel);
+    if( nSegment==1 ){
+      return SQLITE_DONE;
+    }
+  }else{
+    /* This call is to merge all segments at level iLevel. Find the next
+    ** available segment index at level iLevel+1. The call to
+    ** fts3AllocateSegdirIdx() will merge the segments at level iLevel+1 to
+    ** a single iLevel+2 segment if necessary.
+    */
+    iNewLevel = iLevel+1;
+    rc = fts3AllocateSegdirIdx(p, iNewLevel, &iIdx);
+    if( rc!=SQLITE_OK ) return rc;
+    rc = fts3SegmentCount(p, iLevel, &nSegment);
+  }
+  if( rc!=SQLITE_OK ) return rc;
+  assert( nSegment>0 );
+  assert( iNewLevel>=0 );
+
+  /* Allocate space for an array of pointers to segment iterators. */
+  apSegment = (Fts3SegReader**)sqlite3_malloc(sizeof(Fts3SegReader *)*nSegment);
+  if( !apSegment ){
+    return SQLITE_NOMEM;
+  }
+  memset(apSegment, 0, sizeof(Fts3SegReader *)*nSegment);
+
+  /* Allocate a Fts3SegReader structure for each segment being merged. A
+  ** Fts3SegReader stores the state data required to iterate through all
+  ** entries on all leaves of a single segment.
+  */
+  assert( SQL_SELECT_LEVEL+1==SQL_SELECT_ALL_LEVEL);
+  rc = fts3SqlStmt(p, SQL_SELECT_LEVEL+(iLevel<0), &pStmt, 0);
+  if( rc!=SQLITE_OK ) goto finished;
+  sqlite3_bind_int(pStmt, 1, iLevel);
+  for(i=0; SQLITE_ROW==(sqlite3_step(pStmt)); i++){
+    rc = fts3SegReaderNew(p, pStmt, i, &apSegment[i]);
+    if( rc!=SQLITE_OK ){
+      goto finished;
+    }
+  }
+  rc = sqlite3_reset(pStmt);
+  pStmt = 0;
+  if( rc!=SQLITE_OK ) goto finished;
+
+  memset(&filter, 0, sizeof(Fts3SegFilter));
+  filter.flags = FTS3_SEGMENT_REQUIRE_POS;
+  filter.flags |= (iLevel<0 ? FTS3_SEGMENT_IGNORE_EMPTY : 0);
+  rc = sqlite3Fts3SegReaderIterate(p, apSegment, nSegment,
+      &filter, fts3MergeCallback, (void *)&pWriter
+  );
+  if( rc!=SQLITE_OK ) goto finished;
+
+  rc = fts3DeleteSegdir(p, iLevel, apSegment, nSegment);
+  if( rc==SQLITE_OK ){
+    rc = fts3SegWriterFlush(p, pWriter, iNewLevel, iIdx);
+  }
+
+ finished:
+  fts3SegWriterFree(pWriter);
+  if( apSegment ){
+    for(i=0; i<nSegment; i++){
+      sqlite3Fts3SegReaderFree(p, apSegment[i]);
+    }
+    sqlite3_free(apSegment);
+  }
+  sqlite3_reset(pStmt);
+  return rc;
+}
+
+/*
+** This is a comparison function used as a qsort() callback when sorting
+** an array of pending terms by term. This occurs as part of flushing
+** the contents of the pending-terms hash table to the database.
+*/
+static int qsortCompare(const void *lhs, const void *rhs){
+  char *z1 = fts3HashKey(*(Fts3HashElem **)lhs);
+  char *z2 = fts3HashKey(*(Fts3HashElem **)rhs);
+  int n1 = fts3HashKeysize(*(Fts3HashElem **)lhs);
+  int n2 = fts3HashKeysize(*(Fts3HashElem **)rhs);
+
+  int n = (n1<n2 ? n1 : n2);
+  int c = memcmp(z1, z2, n);
+  if( c==0 ){
+    c = n1 - n2;
+  }
+  return c;
+}
+
+
+/*
+** Flush the contents of pendingTerms to a level 0 segment.
+*/
+SQLITE_PRIVATE int sqlite3Fts3PendingTermsFlush(Fts3Table *p){
+  Fts3HashElem *pElem;
+  int idx, rc, i;
+  Fts3HashElem **apElem;          /* Array of pointers to hash elements */
+  int nElem;                      /* Number of terms in new segment */
+  SegmentWriter *pWriter = 0;     /* Used to write the segment */
+
+  /* Find the number of terms that will make up the new segment. If there
+  ** are no terms, return early (do not bother to write an empty segment).
+  */
+  nElem = fts3HashCount(&p->pendingTerms);
+  if( nElem==0 ){
+    assert( p->nPendingData==0 );
+    return SQLITE_OK;
+  }
+
+  /* Determine the next index at level 0, merging as necessary. */
+  rc = fts3AllocateSegdirIdx(p, 0, &idx);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  apElem = sqlite3_malloc(nElem*sizeof(Fts3HashElem *));
+  if( !apElem ){
+    return SQLITE_NOMEM;
+  }
+
+  i = 0;
+  for(pElem=fts3HashFirst(&p->pendingTerms); pElem; pElem=fts3HashNext(pElem)){
+    apElem[i++] = pElem;
+  }
+  assert( i==nElem );
+
+  /* TODO(shess) Should we allow user-defined collation sequences,
+  ** here?  I think we only need that once we support prefix searches.
+  ** Also, should we be using qsort()?
+  */
+  if( nElem>1 ){
+    qsort(apElem, nElem, sizeof(Fts3HashElem *), qsortCompare);
+  }
+
+
+  /* Write the segment tree into the database. */
+  for(i=0; rc==SQLITE_OK && i<nElem; i++){
+    const char *z = fts3HashKey(apElem[i]);
+    int n = fts3HashKeysize(apElem[i]);
+    PendingList *pList = fts3HashData(apElem[i]);
+    rc = fts3SegWriterAdd(p, &pWriter, 0, z, n, pList->aData, pList->nData+1);
+  }
+  if( rc==SQLITE_OK ){
+    rc = fts3SegWriterFlush(p, pWriter, 0, idx);
+  }
+
+  /* Free all allocated resources before returning */
+  fts3SegWriterFree(pWriter);
+  sqlite3_free(apElem);
+  sqlite3Fts3PendingTermsClear(p);
+  return rc;
+}
+
+/*
+** This function does the work for the xUpdate method of FTS3 virtual
+** tables.
+*/
+SQLITE_PRIVATE int sqlite3Fts3UpdateMethod(
+  sqlite3_vtab *pVtab,            /* FTS3 vtab object */
+  int nArg,                       /* Size of argument array */
+  sqlite3_value **apVal,          /* Array of arguments */
+  sqlite_int64 *pRowid            /* OUT: The affected (or effected) rowid */
+){
+  Fts3Table *p = (Fts3Table *)pVtab;
+  int rc = SQLITE_OK;             /* Return Code */
+  int isRemove = 0;               /* True for an UPDATE or DELETE */
+  sqlite3_int64 iRemove;          /* Rowid removed by UPDATE or DELETE */
+
+  /* If this is a DELETE or UPDATE operation, remove the old record. */
+  if( sqlite3_value_type(apVal[0])!=SQLITE_NULL ){
+    int isEmpty;
+    rc = fts3IsEmpty(p, apVal, &isEmpty);
+    if( rc==SQLITE_OK ){
+      if( isEmpty ){
+        /* Deleting this row means the whole table is empty. In this case
+        ** delete the contents of all three tables and throw away any
+        ** data in the pendingTerms hash table.
+        */
+        rc = fts3DeleteAll(p);
+      }else{
+        isRemove = 1;
+        iRemove = sqlite3_value_int64(apVal[0]);
+        rc = fts3PendingTermsDocid(p, iRemove);
+        if( rc==SQLITE_OK ){
+          rc = fts3DeleteTerms(p, apVal);
+          if( rc==SQLITE_OK ){
+            rc = fts3SqlExec(p, SQL_DELETE_CONTENT, apVal);
+          }
+        }
+      }
+    }
+  }
+
+  /* If this is an INSERT or UPDATE operation, insert the new record. */
+  if( nArg>1 && rc==SQLITE_OK ){
+    rc = fts3InsertData(p, apVal, pRowid);
+    if( rc==SQLITE_OK && (!isRemove || *pRowid!=iRemove) ){
+      rc = fts3PendingTermsDocid(p, *pRowid);
+    }
+    if( rc==SQLITE_OK ){
+      rc = fts3InsertTerms(p, apVal);
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Flush any data in the pending-terms hash table to disk. If successful,
+** merge all segments in the database (including the new segment, if
+** there was any data to flush) into a single segment.
+*/
+SQLITE_PRIVATE int sqlite3Fts3Optimize(Fts3Table *p){
+  int rc = sqlite3Fts3PendingTermsFlush(p);
+  if( rc==SQLITE_OK ){
+    rc = fts3SegmentMerge(p, -1);
+  }
+  return rc;
+}
+
+#endif
+
+/************** End of fts3_write.c ******************************************/
+/************** Begin file fts3_snippet.c ************************************/
+/*
+** 2009 Oct 23
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+*/
+
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+
+typedef struct Snippet Snippet;
+
+/*
+** An instance of the following structure keeps track of generated
+** matching-word offset information and snippets.
+*/
+struct Snippet {
+  int nMatch;                     /* Total number of matches */
+  int nAlloc;                     /* Space allocated for aMatch[] */
+  struct snippetMatch {  /* One entry for each matching term */
+    char snStatus;       /* Status flag for use while constructing snippets */
+    short int iCol;      /* The column that contains the match */
+    short int iTerm;     /* The index in Query.pTerms[] of the matching term */
+    int iToken;          /* The index of the matching document token */
+    short int nByte;     /* Number of bytes in the term */
+    int iStart;          /* The offset to the first character of the term */
+  } *aMatch;                      /* Points to space obtained from malloc */
+  char *zOffset;                  /* Text rendering of aMatch[] */
+  int nOffset;                    /* strlen(zOffset) */
+  char *zSnippet;                 /* Snippet text */
+  int nSnippet;                   /* strlen(zSnippet) */
+};
+
+
+/* It is not safe to call isspace(), tolower(), or isalnum() on
+** hi-bit-set characters.  This is the same solution used in the
+** tokenizer.
+*/
+/* TODO(shess) The snippet-generation code should be using the
+** tokenizer-generated tokens rather than doing its own local
+** tokenization.
+*/
+/* TODO(shess) Is __isascii() a portable version of (c&0x80)==0? */
+static int safe_isspace(char c){
+  return (c&0x80)==0 ? isspace(c) : 0;
+}
+static int safe_isalnum(char c){
+  return (c&0x80)==0 ? isalnum(c) : 0;
+}
+
+/*******************************************************************/
+/* DataBuffer is used to collect data into a buffer in piecemeal
+** fashion.  It implements the usual distinction between amount of
+** data currently stored (nData) and buffer capacity (nCapacity).
+**
+** dataBufferInit - create a buffer with given initial capacity.
+** dataBufferReset - forget buffer's data, retaining capacity.
+** dataBufferSwap - swap contents of two buffers.
+** dataBufferExpand - expand capacity without adding data.
+** dataBufferAppend - append data.
+** dataBufferAppend2 - append two pieces of data at once.
+** dataBufferReplace - replace buffer's data.
+*/
+typedef struct DataBuffer {
+  char *pData;          /* Pointer to malloc'ed buffer. */
+  int nCapacity;        /* Size of pData buffer. */
+  int nData;            /* End of data loaded into pData. */
+} DataBuffer;
+
+static void dataBufferInit(DataBuffer *pBuffer, int nCapacity){
+  assert( nCapacity>=0 );
+  pBuffer->nData = 0;
+  pBuffer->nCapacity = nCapacity;
+  pBuffer->pData = nCapacity==0 ? NULL : sqlite3_malloc(nCapacity);
+}
+static void dataBufferReset(DataBuffer *pBuffer){
+  pBuffer->nData = 0;
+}
+static void dataBufferExpand(DataBuffer *pBuffer, int nAddCapacity){
+  assert( nAddCapacity>0 );
+  /* TODO(shess) Consider expanding more aggressively.  Note that the
+  ** underlying malloc implementation may take care of such things for
+  ** us already.
+  */
+  if( pBuffer->nData+nAddCapacity>pBuffer->nCapacity ){
+    pBuffer->nCapacity = pBuffer->nData+nAddCapacity;
+    pBuffer->pData = sqlite3_realloc(pBuffer->pData, pBuffer->nCapacity);
+  }
+}
+static void dataBufferAppend(DataBuffer *pBuffer,
+                             const char *pSource, int nSource){
+  assert( nSource>0 && pSource!=NULL );
+  dataBufferExpand(pBuffer, nSource);
+  memcpy(pBuffer->pData+pBuffer->nData, pSource, nSource);
+  pBuffer->nData += nSource;
+}
+static void dataBufferAppend2(DataBuffer *pBuffer,
+                              const char *pSource1, int nSource1,
+                              const char *pSource2, int nSource2){
+  assert( nSource1>0 && pSource1!=NULL );
+  assert( nSource2>0 && pSource2!=NULL );
+  dataBufferExpand(pBuffer, nSource1+nSource2);
+  memcpy(pBuffer->pData+pBuffer->nData, pSource1, nSource1);
+  memcpy(pBuffer->pData+pBuffer->nData+nSource1, pSource2, nSource2);
+  pBuffer->nData += nSource1+nSource2;
+}
+static void dataBufferReplace(DataBuffer *pBuffer,
+                              const char *pSource, int nSource){
+  dataBufferReset(pBuffer);
+  dataBufferAppend(pBuffer, pSource, nSource);
+}
+
+
+/* StringBuffer is a null-terminated version of DataBuffer. */
+typedef struct StringBuffer {
+  DataBuffer b;            /* Includes null terminator. */
+} StringBuffer;
+
+static void initStringBuffer(StringBuffer *sb){
+  dataBufferInit(&sb->b, 100);
+  dataBufferReplace(&sb->b, "", 1);
+}
+static int stringBufferLength(StringBuffer *sb){
+  return sb->b.nData-1;
+}
+static char *stringBufferData(StringBuffer *sb){
+  return sb->b.pData;
+}
+
+static void nappend(StringBuffer *sb, const char *zFrom, int nFrom){
+  assert( sb->b.nData>0 );
+  if( nFrom>0 ){
+    sb->b.nData--;
+    dataBufferAppend2(&sb->b, zFrom, nFrom, "", 1);
+  }
+}
+static void append(StringBuffer *sb, const char *zFrom){
+  nappend(sb, zFrom, strlen(zFrom));
+}
+
+static int endsInWhiteSpace(StringBuffer *p){
+  return stringBufferLength(p)>0 &&
+    safe_isspace(stringBufferData(p)[stringBufferLength(p)-1]);
+}
+
+/* If the StringBuffer ends in something other than white space, add a
+** single space character to the end.
+*/
+static void appendWhiteSpace(StringBuffer *p){
+  if( stringBufferLength(p)==0 ) return;
+  if( !endsInWhiteSpace(p) ) append(p, " ");
+}
+
+/* Remove white space from the end of the StringBuffer */
+static void trimWhiteSpace(StringBuffer *p){
+  while( endsInWhiteSpace(p) ){
+    p->b.pData[--p->b.nData-1] = '\0';
+  }
+}
+
+
+/*
+** Release all memory associated with the Snippet structure passed as
+** an argument.
+*/
+static void fts3SnippetFree(Snippet *p){
+  sqlite3_free(p->aMatch);
+  sqlite3_free(p->zOffset);
+  sqlite3_free(p->zSnippet);
+  sqlite3_free(p);
+}
+
+/*
+** Append a single entry to the p->aMatch[] log.
+*/
+static void snippetAppendMatch(
+  Snippet *p,               /* Append the entry to this snippet */
+  int iCol, int iTerm,      /* The column and query term */
+  int iToken,               /* Matching token in document */
+  int iStart, int nByte     /* Offset and size of the match */
+){
+  int i;
+  struct snippetMatch *pMatch;
+  if( p->nMatch+1>=p->nAlloc ){
+    p->nAlloc = p->nAlloc*2 + 10;
+    p->aMatch = sqlite3_realloc(p->aMatch, p->nAlloc*sizeof(p->aMatch[0]) );
+    if( p->aMatch==0 ){
+      p->nMatch = 0;
+      p->nAlloc = 0;
+      return;
+    }
+  }
+  i = p->nMatch++;
+  pMatch = &p->aMatch[i];
+  pMatch->iCol = iCol;
+  pMatch->iTerm = iTerm;
+  pMatch->iToken = iToken;
+  pMatch->iStart = iStart;
+  pMatch->nByte = nByte;
+}
+
+/*
+** Sizing information for the circular buffer used in snippetOffsetsOfColumn()
+*/
+#define FTS3_ROTOR_SZ   (32)
+#define FTS3_ROTOR_MASK (FTS3_ROTOR_SZ-1)
+
+/*
+** Function to iterate through the tokens of a compiled expression.
+**
+** Except, skip all tokens on the right-hand side of a NOT operator.
+** This function is used to find tokens as part of snippet and offset
+** generation and we do nt want snippets and offsets to report matches
+** for tokens on the RHS of a NOT.
+*/
+static int fts3NextExprToken(Fts3Expr **ppExpr, int *piToken){
+  Fts3Expr *p = *ppExpr;
+  int iToken = *piToken;
+  if( iToken<0 ){
+    /* In this case the expression p is the root of an expression tree.
+    ** Move to the first token in the expression tree.
+    */
+    while( p->pLeft ){
+      p = p->pLeft;
+    }
+    iToken = 0;
+  }else{
+    assert(p && p->eType==FTSQUERY_PHRASE );
+    if( iToken<(p->pPhrase->nToken-1) ){
+      iToken++;
+    }else{
+      iToken = 0;
+      while( p->pParent && p->pParent->pLeft!=p ){
+        assert( p->pParent->pRight==p );
+        p = p->pParent;
+      }
+      p = p->pParent;
+      if( p ){
+        assert( p->pRight!=0 );
+        p = p->pRight;
+        while( p->pLeft ){
+          p = p->pLeft;
+        }
+      }
+    }
+  }
+
+  *ppExpr = p;
+  *piToken = iToken;
+  return p?1:0;
+}
+
+/*
+** Return TRUE if the expression node pExpr is located beneath the
+** RHS of a NOT operator.
+*/
+static int fts3ExprBeneathNot(Fts3Expr *p){
+  Fts3Expr *pParent;
+  while( p ){
+    pParent = p->pParent;
+    if( pParent && pParent->eType==FTSQUERY_NOT && pParent->pRight==p ){
+      return 1;
+    }
+    p = pParent;
+  }
+  return 0;
+}
+
+/*
+** Add entries to pSnippet->aMatch[] for every match that occurs against
+** document zDoc[0..nDoc-1] which is stored in column iColumn.
+*/
+static void snippetOffsetsOfColumn(
+  Fts3Cursor *pCur,         /* The fulltest search cursor */
+  Snippet *pSnippet,             /* The Snippet object to be filled in */
+  int iColumn,                   /* Index of fulltext table column */
+  const char *zDoc,              /* Text of the fulltext table column */
+  int nDoc                       /* Length of zDoc in bytes */
+){
+  const sqlite3_tokenizer_module *pTModule;  /* The tokenizer module */
+  sqlite3_tokenizer *pTokenizer;             /* The specific tokenizer */
+  sqlite3_tokenizer_cursor *pTCursor;        /* Tokenizer cursor */
+  Fts3Table *pVtab;                /* The full text index */
+  int nColumn;                         /* Number of columns in the index */
+  int i, j;                            /* Loop counters */
+  int rc;                              /* Return code */
+  unsigned int match, prevMatch;       /* Phrase search bitmasks */
+  const char *zToken;                  /* Next token from the tokenizer */
+  int nToken;                          /* Size of zToken */
+  int iBegin, iEnd, iPos;              /* Offsets of beginning and end */
+
+  /* The following variables keep a circular buffer of the last
+  ** few tokens */
+  unsigned int iRotor = 0;             /* Index of current token */
+  int iRotorBegin[FTS3_ROTOR_SZ];      /* Beginning offset of token */
+  int iRotorLen[FTS3_ROTOR_SZ];        /* Length of token */
+
+  pVtab =  (Fts3Table *)pCur->base.pVtab;
+  nColumn = pVtab->nColumn;
+  pTokenizer = pVtab->pTokenizer;
+  pTModule = pTokenizer->pModule;
+  rc = pTModule->xOpen(pTokenizer, zDoc, nDoc, &pTCursor);
+  if( rc ) return;
+  pTCursor->pTokenizer = pTokenizer;
+
+  prevMatch = 0;
+  while( !pTModule->xNext(pTCursor, &zToken, &nToken, &iBegin, &iEnd, &iPos) ){
+    Fts3Expr *pIter = pCur->pExpr;
+    int iIter = -1;
+    iRotorBegin[iRotor&FTS3_ROTOR_MASK] = iBegin;
+    iRotorLen[iRotor&FTS3_ROTOR_MASK] = iEnd-iBegin;
+    match = 0;
+    for(i=0; i<(FTS3_ROTOR_SZ-1) && fts3NextExprToken(&pIter, &iIter); i++){
+      int nPhrase;                    /* Number of tokens in current phrase */
+      struct PhraseToken *pToken;     /* Current token */
+      int iCol;                       /* Column index */
+
+      if( fts3ExprBeneathNot(pIter) ) continue;
+      nPhrase = pIter->pPhrase->nToken;
+      pToken = &pIter->pPhrase->aToken[iIter];
+      iCol = pIter->pPhrase->iColumn;
+      if( iCol>=0 && iCol<nColumn && iCol!=iColumn ) continue;
+      if( pToken->n>nToken ) continue;
+      if( !pToken->isPrefix && pToken->n<nToken ) continue;
+      assert( pToken->n<=nToken );
+      if( memcmp(pToken->z, zToken, pToken->n) ) continue;
+      if( iIter>0 && (prevMatch & (1<<i))==0 ) continue;
+      match |= 1<<i;
+      if( i==(FTS3_ROTOR_SZ-2) || nPhrase==iIter+1 ){
+        for(j=nPhrase-1; j>=0; j--){
+          int k = (iRotor-j) & FTS3_ROTOR_MASK;
+          snippetAppendMatch(pSnippet, iColumn, i-j, iPos-j,
+                iRotorBegin[k], iRotorLen[k]);
+        }
+      }
+    }
+    prevMatch = match<<1;
+    iRotor++;
+  }
+  pTModule->xClose(pTCursor);
+}
+
+/*
+** Remove entries from the pSnippet structure to account for the NEAR
+** operator. When this is called, pSnippet contains the list of token
+** offsets produced by treating all NEAR operators as AND operators.
+** This function removes any entries that should not be present after
+** accounting for the NEAR restriction. For example, if the queried
+** document is:
+**
+**     "A B C D E A"
+**
+** and the query is:
+**
+**     A NEAR/0 E
+**
+** then when this function is called the Snippet contains token offsets
+** 0, 4 and 5. This function removes the "0" entry (because the first A
+** is not near enough to an E).
+**
+** When this function is called, the value pointed to by parameter piLeft is
+** the integer id of the left-most token in the expression tree headed by
+** pExpr. This function increments *piLeft by the total number of tokens
+** in the expression tree headed by pExpr.
+**
+** Return 1 if any trimming occurs.  Return 0 if no trimming is required.
+*/
+static int trimSnippetOffsets(
+  Fts3Expr *pExpr,      /* The search expression */
+  Snippet *pSnippet,    /* The set of snippet offsets to be trimmed */
+  int *piLeft           /* Index of left-most token in pExpr */
+){
+  if( pExpr ){
+    if( trimSnippetOffsets(pExpr->pLeft, pSnippet, piLeft) ){
+      return 1;
+    }
+
+    switch( pExpr->eType ){
+      case FTSQUERY_PHRASE:
+        *piLeft += pExpr->pPhrase->nToken;
+        break;
+      case FTSQUERY_NEAR: {
+        /* The right-hand-side of a NEAR operator is always a phrase. The
+        ** left-hand-side is either a phrase or an expression tree that is
+        ** itself headed by a NEAR operator. The following initializations
+        ** set local variable iLeft to the token number of the left-most
+        ** token in the right-hand phrase, and iRight to the right most
+        ** token in the same phrase. For example, if we had:
+        **
+        **     <col> MATCH '"abc def" NEAR/2 "ghi jkl"'
+        **
+        ** then iLeft will be set to 2 (token number of ghi) and nToken will
+        ** be set to 4.
+        */
+        Fts3Expr *pLeft = pExpr->pLeft;
+        Fts3Expr *pRight = pExpr->pRight;
+        int iLeft = *piLeft;
+        int nNear = pExpr->nNear;
+        int nToken = pRight->pPhrase->nToken;
+        int jj, ii;
+        if( pLeft->eType==FTSQUERY_NEAR ){
+          pLeft = pLeft->pRight;
+        }
+        assert( pRight->eType==FTSQUERY_PHRASE );
+        assert( pLeft->eType==FTSQUERY_PHRASE );
+        nToken += pLeft->pPhrase->nToken;
+
+        for(ii=0; ii<pSnippet->nMatch; ii++){
+          struct snippetMatch *p = &pSnippet->aMatch[ii];
+          if( p->iTerm==iLeft ){
+            int isOk = 0;
+            /* Snippet ii is an occurence of query term iLeft in the document.
+            ** It occurs at position (p->iToken) of the document. We now
+            ** search for an instance of token (iLeft-1) somewhere in the
+            ** range (p->iToken - nNear)...(p->iToken + nNear + nToken) within
+            ** the set of snippetMatch structures. If one is found, proceed.
+            ** If one cannot be found, then remove snippets ii..(ii+N-1)
+            ** from the matching snippets, where N is the number of tokens
+            ** in phrase pRight->pPhrase.
+            */
+            for(jj=0; isOk==0 && jj<pSnippet->nMatch; jj++){
+              struct snippetMatch *p2 = &pSnippet->aMatch[jj];
+              if( p2->iTerm==(iLeft-1) ){
+                if( p2->iToken>=(p->iToken-nNear-1)
+                 && p2->iToken<(p->iToken+nNear+nToken)
+                ){
+                  isOk = 1;
+                }
+              }
+            }
+            if( !isOk ){
+              int kk;
+              for(kk=0; kk<pRight->pPhrase->nToken; kk++){
+                pSnippet->aMatch[kk+ii].iTerm = -2;
+              }
+              return 1;
+            }
+          }
+          if( p->iTerm==(iLeft-1) ){
+            int isOk = 0;
+            for(jj=0; isOk==0 && jj<pSnippet->nMatch; jj++){
+              struct snippetMatch *p2 = &pSnippet->aMatch[jj];
+              if( p2->iTerm==iLeft ){
+                if( p2->iToken<=(p->iToken+nNear+1)
+                 && p2->iToken>(p->iToken-nNear-nToken)
+                ){
+                  isOk = 1;
+                }
+              }
+            }
+            if( !isOk ){
+              int kk;
+              for(kk=0; kk<pLeft->pPhrase->nToken; kk++){
+                pSnippet->aMatch[ii-kk].iTerm = -2;
+              }
+              return 1;
+            }
+          }
+        }
+        break;
+      }
+    }
+
+    if( trimSnippetOffsets(pExpr->pRight, pSnippet, piLeft) ){
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** Compute all offsets for the current row of the query.
+** If the offsets have already been computed, this routine is a no-op.
+*/
+static int snippetAllOffsets(Fts3Cursor *pCsr, Snippet **ppSnippet){
+  Fts3Table *p = (Fts3Table *)pCsr->base.pVtab;
+  int nColumn;
+  int iColumn, i;
+  int iFirst, iLast;
+  int iTerm = 0;
+  Snippet *pSnippet;
+
+  if( pCsr->pExpr==0 ){
+    return SQLITE_OK;
+  }
+
+  pSnippet = (Snippet *)sqlite3_malloc(sizeof(Snippet));
+  *ppSnippet = pSnippet;
+  if( !pSnippet ){
+    return SQLITE_NOMEM;
+  }
+  memset(pSnippet, 0, sizeof(Snippet));
+
+  nColumn = p->nColumn;
+  iColumn = (pCsr->eType - 2);
+  if( iColumn<0 || iColumn>=nColumn ){
+    /* Look for matches over all columns of the full-text index */
+    iFirst = 0;
+    iLast = nColumn-1;
+  }else{
+    /* Look for matches in the iColumn-th column of the index only */
+    iFirst = iColumn;
+    iLast = iColumn;
+  }
+  for(i=iFirst; i<=iLast; i++){
+    const char *zDoc;
+    int nDoc;
+    zDoc = (const char*)sqlite3_column_text(pCsr->pStmt, i+1);
+    nDoc = sqlite3_column_bytes(pCsr->pStmt, i+1);
+    snippetOffsetsOfColumn(pCsr, pSnippet, i, zDoc, nDoc);
+  }
+
+  while( trimSnippetOffsets(pCsr->pExpr, pSnippet, &iTerm) ){
+    iTerm = 0;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** Convert the information in the aMatch[] array of the snippet
+** into the string zOffset[0..nOffset-1]. This string is used as
+** the return of the SQL offsets() function.
+*/
+static void snippetOffsetText(Snippet *p){
+  int i;
+  int cnt = 0;
+  StringBuffer sb;
+  char zBuf[200];
+  if( p->zOffset ) return;
+  initStringBuffer(&sb);
+  for(i=0; i<p->nMatch; i++){
+    struct snippetMatch *pMatch = &p->aMatch[i];
+    if( pMatch->iTerm>=0 ){
+      /* If snippetMatch.iTerm is less than 0, then the match was
+      ** discarded as part of processing the NEAR operator (see the
+      ** trimSnippetOffsetsForNear() function for details). Ignore
+      ** it in this case
+      */
+      zBuf[0] = ' ';
+      sqlite3_snprintf(sizeof(zBuf)-1, &zBuf[cnt>0], "%d %d %d %d",
+          pMatch->iCol, pMatch->iTerm, pMatch->iStart, pMatch->nByte);
+      append(&sb, zBuf);
+      cnt++;
+    }
+  }
+  p->zOffset = stringBufferData(&sb);
+  p->nOffset = stringBufferLength(&sb);
+}
+
+/*
+** zDoc[0..nDoc-1] is phrase of text.  aMatch[0..nMatch-1] are a set
+** of matching words some of which might be in zDoc.  zDoc is column
+** number iCol.
+**
+** iBreak is suggested spot in zDoc where we could begin or end an
+** excerpt.  Return a value similar to iBreak but possibly adjusted
+** to be a little left or right so that the break point is better.
+*/
+static int wordBoundary(
+  int iBreak,                   /* The suggested break point */
+  const char *zDoc,             /* Document text */
+  int nDoc,                     /* Number of bytes in zDoc[] */
+  struct snippetMatch *aMatch,  /* Matching words */
+  int nMatch,                   /* Number of entries in aMatch[] */
+  int iCol                      /* The column number for zDoc[] */
+){
+  int i;
+  if( iBreak<=10 ){
+    return 0;
+  }
+  if( iBreak>=nDoc-10 ){
+    return nDoc;
+  }
+  for(i=0; i<nMatch && aMatch[i].iCol<iCol; i++){}
+  while( i<nMatch && aMatch[i].iStart+aMatch[i].nByte<iBreak ){ i++; }
+  if( i<nMatch ){
+    if( aMatch[i].iStart<iBreak+10 ){
+      return aMatch[i].iStart;
+    }
+    if( i>0 && aMatch[i-1].iStart+aMatch[i-1].nByte>=iBreak ){
+      return aMatch[i-1].iStart;
+    }
+  }
+  for(i=1; i<=10; i++){
+    if( safe_isspace(zDoc[iBreak-i]) ){
+      return iBreak - i + 1;
+    }
+    if( safe_isspace(zDoc[iBreak+i]) ){
+      return iBreak + i + 1;
+    }
+  }
+  return iBreak;
+}
+
+
+
+/*
+** Allowed values for Snippet.aMatch[].snStatus
+*/
+#define SNIPPET_IGNORE  0   /* It is ok to omit this match from the snippet */
+#define SNIPPET_DESIRED 1   /* We want to include this match in the snippet */
+
+/*
+** Generate the text of a snippet.
+*/
+static void snippetText(
+  Fts3Cursor *pCursor,   /* The cursor we need the snippet for */
+  Snippet *pSnippet,
+  const char *zStartMark,     /* Markup to appear before each match */
+  const char *zEndMark,       /* Markup to appear after each match */
+  const char *zEllipsis       /* Ellipsis mark */
+){
+  int i, j;
+  struct snippetMatch *aMatch;
+  int nMatch;
+  int nDesired;
+  StringBuffer sb;
+  int tailCol;
+  int tailOffset;
+  int iCol;
+  int nDoc;
+  const char *zDoc;
+  int iStart, iEnd;
+  int tailEllipsis = 0;
+  int iMatch;
+
+
+  sqlite3_free(pSnippet->zSnippet);
+  pSnippet->zSnippet = 0;
+  aMatch = pSnippet->aMatch;
+  nMatch = pSnippet->nMatch;
+  initStringBuffer(&sb);
+
+  for(i=0; i<nMatch; i++){
+    aMatch[i].snStatus = SNIPPET_IGNORE;
+  }
+  nDesired = 0;
+  for(i=0; i<FTS3_ROTOR_SZ; i++){
+    for(j=0; j<nMatch; j++){
+      if( aMatch[j].iTerm==i ){
+        aMatch[j].snStatus = SNIPPET_DESIRED;
+        nDesired++;
+        break;
+      }
+    }
+  }
+
+  iMatch = 0;
+  tailCol = -1;
+  tailOffset = 0;
+  for(i=0; i<nMatch && nDesired>0; i++){
+    if( aMatch[i].snStatus!=SNIPPET_DESIRED ) continue;
+    nDesired--;
+    iCol = aMatch[i].iCol;
+    zDoc = (const char*)sqlite3_column_text(pCursor->pStmt, iCol+1);
+    nDoc = sqlite3_column_bytes(pCursor->pStmt, iCol+1);
+    iStart = aMatch[i].iStart - 40;
+    iStart = wordBoundary(iStart, zDoc, nDoc, aMatch, nMatch, iCol);
+    if( iStart<=10 ){
+      iStart = 0;
+    }
+    if( iCol==tailCol && iStart<=tailOffset+20 ){
+      iStart = tailOffset;
+    }
+    if( (iCol!=tailCol && tailCol>=0) || iStart!=tailOffset ){
+      trimWhiteSpace(&sb);
+      appendWhiteSpace(&sb);
+      append(&sb, zEllipsis);
+      appendWhiteSpace(&sb);
+    }
+    iEnd = aMatch[i].iStart + aMatch[i].nByte + 40;
+    iEnd = wordBoundary(iEnd, zDoc, nDoc, aMatch, nMatch, iCol);
+    if( iEnd>=nDoc-10 ){
+      iEnd = nDoc;
+      tailEllipsis = 0;
+    }else{
+      tailEllipsis = 1;
+    }
+    while( iMatch<nMatch && aMatch[iMatch].iCol<iCol ){ iMatch++; }
+    while( iStart<iEnd ){
+      while( iMatch<nMatch && aMatch[iMatch].iStart<iStart
+             && aMatch[iMatch].iCol<=iCol ){
+        iMatch++;
+      }
+      if( iMatch<nMatch && aMatch[iMatch].iStart<iEnd
+             && aMatch[iMatch].iCol==iCol ){
+        nappend(&sb, &zDoc[iStart], aMatch[iMatch].iStart - iStart);
+        iStart = aMatch[iMatch].iStart;
+        append(&sb, zStartMark);
+        nappend(&sb, &zDoc[iStart], aMatch[iMatch].nByte);
+        append(&sb, zEndMark);
+        iStart += aMatch[iMatch].nByte;
+        for(j=iMatch+1; j<nMatch; j++){
+          if( aMatch[j].iTerm==aMatch[iMatch].iTerm
+              && aMatch[j].snStatus==SNIPPET_DESIRED ){
+            nDesired--;
+            aMatch[j].snStatus = SNIPPET_IGNORE;
+          }
+        }
+      }else{
+        nappend(&sb, &zDoc[iStart], iEnd - iStart);
+        iStart = iEnd;
+      }
+    }
+    tailCol = iCol;
+    tailOffset = iEnd;
+  }
+  trimWhiteSpace(&sb);
+  if( tailEllipsis ){
+    appendWhiteSpace(&sb);
+    append(&sb, zEllipsis);
+  }
+  pSnippet->zSnippet = stringBufferData(&sb);
+  pSnippet->nSnippet = stringBufferLength(&sb);
+}
+
+SQLITE_PRIVATE void sqlite3Fts3Offsets(
+  sqlite3_context *pCtx,          /* SQLite function call context */
+  Fts3Cursor *pCsr                /* Cursor object */
+){
+  Snippet *p;                     /* Snippet structure */
+  int rc = snippetAllOffsets(pCsr, &p);
+  snippetOffsetText(p);
+  sqlite3_result_text(pCtx, p->zOffset, p->nOffset, SQLITE_TRANSIENT);
+  fts3SnippetFree(p);
+}
+
+SQLITE_PRIVATE void sqlite3Fts3Snippet(
+  sqlite3_context *pCtx,          /* SQLite function call context */
+  Fts3Cursor *pCsr,               /* Cursor object */
+  const char *zStart,             /* Snippet start text - "<b>" */
+  const char *zEnd,               /* Snippet end text - "</b>" */
+  const char *zEllipsis           /* Snippet ellipsis text - "<b>...</b>" */
+){
+  Snippet *p;                     /* Snippet structure */
+  int rc = snippetAllOffsets(pCsr, &p);
+  snippetText(pCsr, p, zStart, zEnd, zEllipsis);
+  sqlite3_result_text(pCtx, p->zSnippet, p->nSnippet, SQLITE_TRANSIENT);
+  fts3SnippetFree(p);
+}
+
+#endif
+
+/************** End of fts3_snippet.c ****************************************/
 /************** Begin file rtree.c *******************************************/
 /*
 ** 2001 September 15
 **
 ** The author disclaims copyright to this source code.  In place of
@@ -107233,12 +105554,10 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 ** This file contains code for implementations of the r-tree and r*-tree
 ** algorithms packaged as an SQLite virtual table module.
-**
-** $Id: rtree.c,v 1.14 2009/08/06 18:36:47 danielk1977 Exp $
 */
 
 #if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_RTREE)
 
 /*

Modified src/sqlite3.h from [da93a40cb3] to [d1070060b5].

@@ -117,13 +117,13 @@
 ** [sqlite3_libversion_number()], [sqlite3_sourceid()],
 ** [sqlite_version()] and [sqlite_source_id()].
 **
 ** Requirements: [H10011] [H10014]
 */
-#define SQLITE_VERSION        "3.6.20"
-#define SQLITE_VERSION_NUMBER 3006020
-#define SQLITE_SOURCE_ID      "2009-11-04 23:02:52 f1c09acaca3e205acf5b077c9b2d0fe35f035c1e"
+#define SQLITE_VERSION        "3.6.21"
+#define SQLITE_VERSION_NUMBER 3006021
+#define SQLITE_SOURCE_ID      "2009-11-23 13:17:27 39214aee6553db76309851e7aa74fcc02d4f59b7"
 
 /*
 ** CAPI3REF: Run-Time Library Version Numbers {H10020} <S60100>
 ** KEYWORDS: sqlite3_version
 **