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File src/printf.c part of check-in [8c3ec00311] - On the printf extension converters (ex: %T, %w) the "alternate form flag" (ex: %#T, %#w) means first read an integer from the argument list and then only process that number of characters from the string or blob that is read next from the argument list. by drh on 2008-02-04 19:07:58.

/*
** Copyright (c) 2006 D. Richard Hipp
**
** This program is free software; you can redistribute it and/or
** modify it under the terms of the GNU General Public
** License version 2 as published by the Free Software Foundation.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
** General Public License for more details.
** 
** You should have received a copy of the GNU General Public
** License along with this library; if not, write to the
** Free Software Foundation, Inc., 59 Temple Place - Suite 330,
** Boston, MA  02111-1307, USA.
**
** Author contact information:
**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*******************************************************************************
**
** An implementation of printf() with extra conversion fields.
*/
#include "config.h"
#include "printf.h"

/*
** Conversion types fall into various categories as defined by the
** following enumeration.
*/
#define etRADIX       1 /* Integer types.  %d, %x, %o, and so forth */
#define etFLOAT       2 /* Floating point.  %f */
#define etEXP         3 /* Exponentional notation. %e and %E */
#define etGENERIC     4 /* Floating or exponential, depending on exponent. %g */
#define etSIZE        5 /* Return number of characters processed so far. %n */
#define etSTRING      6 /* Strings. %s */
#define etDYNSTRING   7 /* Dynamically allocated strings. %z */
#define etPERCENT     8 /* Percent symbol. %% */
#define etCHARX       9 /* Characters. %c */
#define etERROR      10 /* Used to indicate no such conversion type */
/* The rest are extensions, not normally found in printf() */
#define etBLOB       11 /* Blob objects.  %b */
#define etBLOBSQL    12 /* Blob objects quoted for SQL.  %B */
#define etSQLESCAPE  13 /* Strings with '\'' doubled.  %q */
#define etSQLESCAPE2 14 /* Strings with '\'' doubled and enclosed in '',
                          NULL pointers replaced by SQL NULL.  %Q */
#define etPOINTER    15 /* The %p conversion */
#define etHTMLIZE    16 /* Make text safe for HTML */
#define etHTTPIZE    17 /* Make text safe for HTTP.  "/" encoded as %2f */
#define etURLIZE     18 /* Make text safe for HTTP.  "/" not encoded */
#define etFOSSILIZE  19 /* The fossil header encoding format. */
#define etPATH       20 /* Path type */
#define etWIKISTR    21 /* Wiki text rendered from a char* */
#define etWIKIBLOB   22 /* Wiki text rendered from a Blob* */


/*
** An "etByte" is an 8-bit unsigned value.
*/
typedef unsigned char etByte;

/*
** Each builtin conversion character (ex: the 'd' in "%d") is described
** by an instance of the following structure
*/
typedef struct et_info {   /* Information about each format field */
  char fmttype;            /* The format field code letter */
  etByte base;             /* The base for radix conversion */
  etByte flags;            /* One or more of FLAG_ constants below */
  etByte type;             /* Conversion paradigm */
  etByte charset;          /* Offset into aDigits[] of the digits string */
  etByte prefix;           /* Offset into aPrefix[] of the prefix string */
} et_info;

/*
** Allowed values for et_info.flags
*/
#define FLAG_SIGNED  1     /* True if the value to convert is signed */
#define FLAG_INTERN  2     /* True if for internal use only */
#define FLAG_STRING  4     /* Allow infinity precision */


/*
** The following table is searched linearly, so it is good to put the
** most frequently used conversion types first.
*/
static const char aDigits[] = "0123456789ABCDEF0123456789abcdef";
static const char aPrefix[] = "-x0\000X0";
static const et_info fmtinfo[] = {
  {  'd', 10, 1, etRADIX,      0,  0 },
  {  's',  0, 4, etSTRING,     0,  0 },
  {  'g',  0, 1, etGENERIC,    30, 0 },
  {  'z',  0, 6, etDYNSTRING,  0,  0 },
  {  'q',  0, 4, etSQLESCAPE,  0,  0 },
  {  'Q',  0, 4, etSQLESCAPE2, 0,  0 },
  {  'b',  0, 2, etBLOB,       0,  0 },
  {  'B',  0, 2, etBLOBSQL,    0,  0 },
  {  'w',  0, 2, etWIKISTR,    0,  0 },
  {  'W',  0, 2, etWIKIBLOB,   0,  0 },
  {  'h',  0, 4, etHTMLIZE,    0,  0 },
  {  't',  0, 4, etHTTPIZE,    0,  0 },  /* "/" -> "%2F" */
  {  'T',  0, 4, etURLIZE,     0,  0 },  /* "/" unchanged */
  {  'F',  0, 4, etFOSSILIZE,  0,  0 },
  {  'c',  0, 0, etCHARX,      0,  0 },
  {  'o',  8, 0, etRADIX,      0,  2 },
  {  'u', 10, 0, etRADIX,      0,  0 },
  {  'x', 16, 0, etRADIX,      16, 1 },
  {  'X', 16, 0, etRADIX,      0,  4 },
  {  'f',  0, 1, etFLOAT,      0,  0 },
  {  'e',  0, 1, etEXP,        30, 0 },
  {  'E',  0, 1, etEXP,        14, 0 },
  {  'G',  0, 1, etGENERIC,    14, 0 },
  {  'i', 10, 1, etRADIX,      0,  0 },
  {  'n',  0, 0, etSIZE,       0,  0 },
  {  '%',  0, 0, etPERCENT,    0,  0 },
  {  'p', 16, 0, etPOINTER,    0,  1 },
  {  '/',  0, 0, etPATH,       0,  0 },
};
#define etNINFO  (sizeof(fmtinfo)/sizeof(fmtinfo[0]))

/*
** "*val" is a double such that 0.1 <= *val < 10.0
** Return the ascii code for the leading digit of *val, then
** multiply "*val" by 10.0 to renormalize.
**
** Example:
**     input:     *val = 3.14159
**     output:    *val = 1.4159    function return = '3'
**
** The counter *cnt is incremented each time.  After counter exceeds
** 16 (the number of significant digits in a 64-bit float) '0' is
** always returned.
*/
static int et_getdigit(long double *val, int *cnt){
  int digit;
  long double d;
  if( (*cnt)++ >= 16 ) return '0';
  digit = (int)*val;
  d = digit;
  digit += '0';
  *val = (*val - d)*10.0;
  return digit;
}

/*
** Size of temporary conversion buffer.
*/
#define etBUFSIZE 500

/*
** Find the length of a string as long as that length does not
** exceed N bytes.  If no zero terminator is seen in the first
** N bytes then return N.  If N is negative, then this routine
** is an alias for strlen().
*/
static int strnlen(const char *z, int N){
  int n = 0;
  while( (N-- != 0) && *(z++)!=0 ){ n++; }
  return n;
}


/*
** The root program.  All variations call this core.
**
** INPUTS:
**   func   This is a pointer to a function taking three arguments
**            1. A pointer to anything.  Same as the "arg" parameter.
**            2. A pointer to the list of characters to be output
**               (Note, this list is NOT null terminated.)
**            3. An integer number of characters to be output.
**               (Note: This number might be zero.)
**
**   arg    This is the pointer to anything which will be passed as the
**          first argument to "func".  Use it for whatever you like.
**
**   fmt    This is the format string, as in the usual print.
**
**   ap     This is a pointer to a list of arguments.  Same as in
**          vfprint.
**
** OUTPUTS:
**          The return value is the total number of characters sent to
**          the function "func".  Returns -1 on a error.
**
** Note that the order in which automatic variables are declared below
** seems to make a big difference in determining how fast this beast
** will run.
*/
int vxprintf(
  Blob *pBlob,                       /* Append output to this blob */
  const char *fmt,                   /* Format string */
  va_list ap                         /* arguments */
){
  int c;                     /* Next character in the format string */
  char *bufpt;               /* Pointer to the conversion buffer */
  int precision;             /* Precision of the current field */
  int length;                /* Length of the field */
  int idx;                   /* A general purpose loop counter */
  int count;                 /* Total number of characters output */
  int width;                 /* Width of the current field */
  etByte flag_leftjustify;   /* True if "-" flag is present */
  etByte flag_plussign;      /* True if "+" flag is present */
  etByte flag_blanksign;     /* True if " " flag is present */
  etByte flag_alternateform; /* True if "#" flag is present */
  etByte flag_altform2;      /* True if "!" flag is present */
  etByte flag_zeropad;       /* True if field width constant starts with zero */
  etByte flag_long;          /* True if "l" flag is present */
  etByte flag_longlong;      /* True if the "ll" flag is present */
  etByte done;               /* Loop termination flag */
  u64 longvalue;             /* Value for integer types */
  long double realvalue;     /* Value for real types */
  const et_info *infop;      /* Pointer to the appropriate info structure */
  char buf[etBUFSIZE];       /* Conversion buffer */
  char prefix;               /* Prefix character.  "+" or "-" or " " or '\0'. */
  etByte errorflag = 0;      /* True if an error is encountered */
  etByte xtype;              /* Conversion paradigm */
  char *zExtra;              /* Extra memory used for etTCLESCAPE conversions */
  static const char spaces[] =
   "                                                                         ";
#define etSPACESIZE (sizeof(spaces)-1)
  int  exp, e2;              /* exponent of real numbers */
  double rounder;            /* Used for rounding floating point values */
  etByte flag_dp;            /* True if decimal point should be shown */
  etByte flag_rtz;           /* True if trailing zeros should be removed */
  etByte flag_exp;           /* True to force display of the exponent */
  int nsd;                   /* Number of significant digits returned */

  count = length = 0;
  bufpt = 0;
  for(; (c=(*fmt))!=0; ++fmt){
    if( c!='%' ){
      int amt;
      bufpt = (char *)fmt;
      amt = 1;
      while( (c=(*++fmt))!='%' && c!=0 ) amt++;
      blob_append(pBlob,bufpt,amt);
      count += amt;
      if( c==0 ) break;
    }
    if( (c=(*++fmt))==0 ){
      errorflag = 1;
      blob_append(pBlob,"%",1);
      count++;
      break;
    }
    /* Find out what flags are present */
    flag_leftjustify = flag_plussign = flag_blanksign = 
     flag_alternateform = flag_altform2 = flag_zeropad = 0;
    done = 0;
    do{
      switch( c ){
        case '-':   flag_leftjustify = 1;     break;
        case '+':   flag_plussign = 1;        break;
        case ' ':   flag_blanksign = 1;       break;
        case '#':   flag_alternateform = 1;   break;
        case '!':   flag_altform2 = 1;        break;
        case '0':   flag_zeropad = 1;         break;
        default:    done = 1;                 break;
      }
    }while( !done && (c=(*++fmt))!=0 );
    /* Get the field width */
    width = 0;
    if( c=='*' ){
      width = va_arg(ap,int);
      if( width<0 ){
        flag_leftjustify = 1;
        width = -width;
      }
      c = *++fmt;
    }else{
      while( c>='0' && c<='9' ){
        width = width*10 + c - '0';
        c = *++fmt;
      }
    }
    if( width > etBUFSIZE-10 ){
      width = etBUFSIZE-10;
    }
    /* Get the precision */
    if( c=='.' ){
      precision = 0;
      c = *++fmt;
      if( c=='*' ){
        precision = va_arg(ap,int);
        if( precision<0 ) precision = -precision;
        c = *++fmt;
      }else{
        while( c>='0' && c<='9' ){
          precision = precision*10 + c - '0';
          c = *++fmt;
        }
      }
    }else{
      precision = -1;
    }
    /* Get the conversion type modifier */
    if( c=='l' ){
      flag_long = 1;
      c = *++fmt;
      if( c=='l' ){
        flag_longlong = 1;
        c = *++fmt;
      }else{
        flag_longlong = 0;
      }
    }else{
      flag_long = flag_longlong = 0;
    }
    /* Fetch the info entry for the field */
    infop = 0;
    xtype = etERROR;
    for(idx=0; idx<etNINFO; idx++){
      if( c==fmtinfo[idx].fmttype ){
        infop = &fmtinfo[idx];
        xtype = infop->type;
        break;
      }
    }
    zExtra = 0;

    /* Limit the precision to prevent overflowing buf[] during conversion */
    if( precision>etBUFSIZE-40 && (infop->flags & FLAG_STRING)==0 ){
      precision = etBUFSIZE-40;
    }

    /*
    ** At this point, variables are initialized as follows:
    **
    **   flag_alternateform          TRUE if a '#' is present.
    **   flag_altform2               TRUE if a '!' is present.
    **   flag_plussign               TRUE if a '+' is present.
    **   flag_leftjustify            TRUE if a '-' is present or if the
    **                               field width was negative.
    **   flag_zeropad                TRUE if the width began with 0.
    **   flag_long                   TRUE if the letter 'l' (ell) prefixed
    **                               the conversion character.
    **   flag_longlong               TRUE if the letter 'll' (ell ell) prefixed
    **                               the conversion character.
    **   flag_blanksign              TRUE if a ' ' is present.
    **   width                       The specified field width.  This is
    **                               always non-negative.  Zero is the default.
    **   precision                   The specified precision.  The default
    **                               is -1.
    **   xtype                       The class of the conversion.
    **   infop                       Pointer to the appropriate info struct.
    */
    switch( xtype ){
      case etPOINTER:
        flag_longlong = sizeof(char*)==sizeof(i64);
        flag_long = sizeof(char*)==sizeof(long int);
        /* Fall through into the next case */
      case etRADIX:
        if( infop->flags & FLAG_SIGNED ){
          i64 v;
          if( flag_longlong )   v = va_arg(ap,i64);
          else if( flag_long )  v = va_arg(ap,long int);
          else                  v = va_arg(ap,int);
          if( v<0 ){
            longvalue = -v;
            prefix = '-';
          }else{
            longvalue = v;
            if( flag_plussign )        prefix = '+';
            else if( flag_blanksign )  prefix = ' ';
            else                       prefix = 0;
          }
        }else{
          if( flag_longlong )   longvalue = va_arg(ap,u64);
          else if( flag_long )  longvalue = va_arg(ap,unsigned long int);
          else                  longvalue = va_arg(ap,unsigned int);
          prefix = 0;
        }
        if( longvalue==0 ) flag_alternateform = 0;
        if( flag_zeropad && precision<width-(prefix!=0) ){
          precision = width-(prefix!=0);
        }
        bufpt = &buf[etBUFSIZE-1];
        {
          register const char *cset;      /* Use registers for speed */
          register int base;
          cset = &aDigits[infop->charset];
          base = infop->base;
          do{                                           /* Convert to ascii */
            *(--bufpt) = cset[longvalue%base];
            longvalue = longvalue/base;
          }while( longvalue>0 );
        }
        length = &buf[etBUFSIZE-1]-bufpt;
        for(idx=precision-length; idx>0; idx--){
          *(--bufpt) = '0';                             /* Zero pad */
        }
        if( prefix ) *(--bufpt) = prefix;               /* Add sign */
        if( flag_alternateform && infop->prefix ){      /* Add "0" or "0x" */
          const char *pre;
          char x;
          pre = &aPrefix[infop->prefix];
          if( *bufpt!=pre[0] ){
            for(; (x=(*pre))!=0; pre++) *(--bufpt) = x;
          }
        }
        length = &buf[etBUFSIZE-1]-bufpt;
        break;
      case etFLOAT:
      case etEXP:
      case etGENERIC:
        realvalue = va_arg(ap,double);
        if( precision<0 ) precision = 6;         /* Set default precision */
        if( precision>etBUFSIZE/2-10 ) precision = etBUFSIZE/2-10;
        if( realvalue<0.0 ){
          realvalue = -realvalue;
          prefix = '-';
        }else{
          if( flag_plussign )          prefix = '+';
          else if( flag_blanksign )    prefix = ' ';
          else                         prefix = 0;
        }
        if( xtype==etGENERIC && precision>0 ) precision--;
#if 0
        /* Rounding works like BSD when the constant 0.4999 is used.  Wierd! */
        for(idx=precision, rounder=0.4999; idx>0; idx--, rounder*=0.1);
#else
        /* It makes more sense to use 0.5 */
        for(idx=precision, rounder=0.5; idx>0; idx--, rounder*=0.1);
#endif
        if( xtype==etFLOAT ) realvalue += rounder;
        /* Normalize realvalue to within 10.0 > realvalue >= 1.0 */
        exp = 0;
        if( realvalue>0.0 ){
          while( realvalue>=1e32 && exp<=350 ){ realvalue *= 1e-32; exp+=32; }
          while( realvalue>=1e8 && exp<=350 ){ realvalue *= 1e-8; exp+=8; }
          while( realvalue>=10.0 && exp<=350 ){ realvalue *= 0.1; exp++; }
          while( realvalue<1e-8 && exp>=-350 ){ realvalue *= 1e8; exp-=8; }
          while( realvalue<1.0 && exp>=-350 ){ realvalue *= 10.0; exp--; }
          if( exp>350 || exp<-350 ){
            bufpt = "NaN";
            length = 3;
            break;
          }
        }
        bufpt = buf;
        /*
        ** If the field type is etGENERIC, then convert to either etEXP
        ** or etFLOAT, as appropriate.
        */
        flag_exp = xtype==etEXP;
        if( xtype!=etFLOAT ){
          realvalue += rounder;
          if( realvalue>=10.0 ){ realvalue *= 0.1; exp++; }
        }
        if( xtype==etGENERIC ){
          flag_rtz = !flag_alternateform;
          if( exp<-4 || exp>precision ){
            xtype = etEXP;
          }else{
            precision = precision - exp;
            xtype = etFLOAT;
          }
        }else{
          flag_rtz = 0;
        }
        if( xtype==etEXP ){
          e2 = 0;
        }else{
          e2 = exp;
        }
        nsd = 0;
        flag_dp = (precision>0) | flag_alternateform | flag_altform2;
        /* The sign in front of the number */
        if( prefix ){
          *(bufpt++) = prefix;
        }
        /* Digits prior to the decimal point */
        if( e2<0 ){
          *(bufpt++) = '0';
        }else{
          for(; e2>=0; e2--){
            *(bufpt++) = et_getdigit(&realvalue,&nsd);
          }
        }
        /* The decimal point */
        if( flag_dp ){
          *(bufpt++) = '.';
        }
        /* "0" digits after the decimal point but before the first
        ** significant digit of the number */
        for(e2++; e2<0 && precision>0; precision--, e2++){
          *(bufpt++) = '0';
        }
        /* Significant digits after the decimal point */
        while( (precision--)>0 ){
          *(bufpt++) = et_getdigit(&realvalue,&nsd);
        }
        /* Remove trailing zeros and the "." if no digits follow the "." */
        if( flag_rtz && flag_dp ){
          while( bufpt[-1]=='0' ) *(--bufpt) = 0;
          assert( bufpt>buf );
          if( bufpt[-1]=='.' ){
            if( flag_altform2 ){
              *(bufpt++) = '0';
            }else{
              *(--bufpt) = 0;
            }
          }
        }
        /* Add the "eNNN" suffix */
        if( flag_exp || (xtype==etEXP && exp) ){
          *(bufpt++) = aDigits[infop->charset];
          if( exp<0 ){
            *(bufpt++) = '-'; exp = -exp;
          }else{
            *(bufpt++) = '+';
          }
          if( exp>=100 ){
            *(bufpt++) = (exp/100)+'0';                /* 100's digit */
            exp %= 100;
          }
          *(bufpt++) = exp/10+'0';                     /* 10's digit */
          *(bufpt++) = exp%10+'0';                     /* 1's digit */
        }
        *bufpt = 0;

        /* The converted number is in buf[] and zero terminated. Output it.
        ** Note that the number is in the usual order, not reversed as with
        ** integer conversions. */
        length = bufpt-buf;
        bufpt = buf;

        /* Special case:  Add leading zeros if the flag_zeropad flag is
        ** set and we are not left justified */
        if( flag_zeropad && !flag_leftjustify && length < width){
          int i;
          int nPad = width - length;
          for(i=width; i>=nPad; i--){
            bufpt[i] = bufpt[i-nPad];
          }
          i = prefix!=0;
          while( nPad-- ) bufpt[i++] = '0';
          length = width;
        }
        break;
      case etSIZE:
        *(va_arg(ap,int*)) = count;
        length = width = 0;
        break;
      case etPERCENT:
        buf[0] = '%';
        bufpt = buf;
        length = 1;
        break;
      case etCHARX:
        c = buf[0] = (xtype==etCHARX ? va_arg(ap,int) : *++fmt);
        if( precision>=0 ){
          for(idx=1; idx<precision; idx++) buf[idx] = c;
          length = precision;
        }else{
          length =1;
        }
        bufpt = buf;
        break;
      case etPATH: {
        int i;
        int limit = flag_alternateform ? va_arg(ap,int) : -1;
        char *e = va_arg(ap,char*);
        if( e==0 ){e="";}
        length = strnlen(e, limit);
        zExtra = bufpt = malloc(length+1);
        for( i=0; i<length; i++ ){
          if( e[i]=='\\' ){
            bufpt[i]='/';
          }else{
            bufpt[i]=e[i];
          }
        }
        bufpt[length]='\0';
        break;
      }
      case etSTRING:
      case etDYNSTRING: {
        int limit = flag_alternateform ? va_arg(ap,int) : -1;
        bufpt = va_arg(ap,char*);
        if( bufpt==0 ){
          bufpt = "";
        }else if( xtype==etDYNSTRING ){
          zExtra = bufpt;
        }
        length = strnlen(bufpt, limit);
        if( precision>=0 && precision<length ) length = precision;
        break;
      }
      case etBLOB: {
        int limit = flag_alternateform ? va_arg(ap, int) : -1;
        Blob *pBlob = va_arg(ap, Blob*);
        bufpt = blob_buffer(pBlob);
        length = blob_size(pBlob);
        if( limit>=0 && limit<length ) length = limit;
        break;
      }
      case etBLOBSQL: {
        int limit = flag_alternateform ? va_arg(ap, int) : -1;
        Blob *pBlob = va_arg(ap, Blob*);
        char *zOrig = blob_buffer(pBlob);
        int i, j, n, cnt;
        n = blob_size(pBlob);
        if( limit>=0 && limit<n ) n = limit;
        for(cnt=i=0; i<n; i++){ if( zOrig[i]=='\'' ) cnt++; }
        if( n+cnt+2 > etBUFSIZE ){
          bufpt = zExtra = malloc( n + cnt + 2 );
        }else{
          bufpt = buf;
        }
        bufpt[0] = '\'';
        for(i=0, j=1; i<n; i++, j++){
          if( zOrig[i]=='\'' ){ bufpt[j++] = '\''; }
          bufpt[j] = zOrig[i];
        }
        bufpt[j++] = '\'';
        length = j;
        assert( length==n+cnt+2 );
        break;
      }
      case etSQLESCAPE:
      case etSQLESCAPE2: {
        int i, j, n, ch, isnull;
        int needQuote;
        int limit = flag_alternateform ? va_arg(ap,int) : -1;
        char *escarg = va_arg(ap,char*);
        isnull = escarg==0;
        if( isnull ) escarg = (xtype==etSQLESCAPE2 ? "NULL" : "(NULL)");
        if( limit<0 ) limit = strlen(escarg);
        for(i=n=0; i<limit; i++){
          if( escarg[i]=='\'' )  n++;
        }
        needQuote = !isnull && xtype==etSQLESCAPE2;
        n += i + 1 + needQuote*2;
        if( n>etBUFSIZE ){
          bufpt = zExtra = malloc( n );
          if( bufpt==0 ) return -1;
        }else{
          bufpt = buf;
        }
        j = 0;
        if( needQuote ) bufpt[j++] = '\'';
        for(i=0; i<limit; i++){
          bufpt[j++] = ch = escarg[i];
          if( ch=='\'' ) bufpt[j++] = ch;
        }
        if( needQuote ) bufpt[j++] = '\'';
        bufpt[j] = 0;
        length = j;
        if( precision>=0 && precision<length ) length = precision;
        break;
      }
      case etHTMLIZE: {
        int limit = flag_alternateform ? va_arg(ap,int) : -1;
        char *zMem = va_arg(ap,char*);
        if( zMem==0 ) zMem = "";
        zExtra = bufpt = htmlize(zMem, limit);
        length = strlen(bufpt);
        if( precision>=0 && precision<length ) length = precision;
        break;
      }
      case etHTTPIZE: {
        int limit = flag_alternateform ? va_arg(ap,int) : -1;
        char *zMem = va_arg(ap,char*);
        if( zMem==0 ) zMem = "";
        zExtra = bufpt = httpize(zMem, limit);
        length = strlen(bufpt);
        if( precision>=0 && precision<length ) length = precision;
        break;
      }
      case etURLIZE: {
        int limit = flag_alternateform ? va_arg(ap,int) : -1;
        char *zMem = va_arg(ap,char*);
        if( zMem==0 ) zMem = "";
        zExtra = bufpt = urlize(zMem, limit);
        length = strlen(bufpt);
        if( precision>=0 && precision<length ) length = precision;
        break;
      }
      case etFOSSILIZE: {
        int limit = flag_alternateform ? va_arg(ap,int) : -1;
        char *zMem = va_arg(ap,char*);
        if( zMem==0 ) zMem = "";
        zExtra = bufpt = fossilize(zMem, limit);
        length = strlen(bufpt);
        if( precision>=0 && precision<length ) length = precision;
        break;
      }
      case etWIKISTR: {
        int limit = flag_alternateform ? va_arg(ap,int) : -1;
        char *zWiki = va_arg(ap, char*);
        Blob wiki;
        blob_init(&wiki, zWiki, limit);
        wiki_convert(&wiki, pBlob, WIKI_INLINE);
        blob_reset(&wiki);
        length = width = 0;
        break;
      }
      case etWIKIBLOB: {
        Blob *pWiki = va_arg(ap, Blob*);
        wiki_convert(pWiki, pBlob, WIKI_INLINE);
        length = width = 0;
        break;
      }
      case etERROR:
        buf[0] = '%';
        buf[1] = c;
        errorflag = 0;
        idx = 1+(c!=0);
        blob_append(pBlob,"%",idx);
        count += idx;
        if( c==0 ) fmt--;
        break;
    }/* End switch over the format type */
    /*
    ** The text of the conversion is pointed to by "bufpt" and is
    ** "length" characters long.  The field width is "width".  Do
    ** the output.
    */
    if( !flag_leftjustify ){
      register int nspace;
      nspace = width-length;
      if( nspace>0 ){
        count += nspace;
        while( nspace>=etSPACESIZE ){
          blob_append(pBlob,spaces,etSPACESIZE);
          nspace -= etSPACESIZE;
        }
        if( nspace>0 ) blob_append(pBlob,spaces,nspace);
      }
    }
    if( length>0 ){
      blob_append(pBlob,bufpt,length);
      count += length;
    }
    if( flag_leftjustify ){
      register int nspace;
      nspace = width-length;
      if( nspace>0 ){
        count += nspace;
        while( nspace>=etSPACESIZE ){
          blob_append(pBlob,spaces,etSPACESIZE);
          nspace -= etSPACESIZE;
        }
        if( nspace>0 ) blob_append(pBlob,spaces,nspace);
      }
    }
    if( zExtra ){
      free(zExtra);
    }
  }/* End for loop over the format string */
  return errorflag ? -1 : count;
} /* End of function */

/*
** Print into memory obtained from malloc().
*/
char *mprintf(const char *zFormat, ...){
  va_list ap;
  char *z;
  va_start(ap,zFormat);
  z = vmprintf(zFormat, ap);
  va_end(ap);
  return z;
}
char *vmprintf(const char *zFormat, va_list ap){
  Blob blob = empty_blob;
  blob_vappendf(&blob, zFormat, ap);
  blob_materialize(&blob);
  return blob.aData;
}

/*
** Record an error message in the global g.zErrMsg variable.
**
** If there is already another error message, only overwrite it if
** the current error has a higher priority.
*/
void fossil_error(int iPriority, const char *zFormat, ...){
  va_list ap;
  if( iPriority<=0 ){
    return;
  }
  if( g.zErrMsg ){
    if( g.iErrPriority>=iPriority ){
      return;
    }
    free(g.zErrMsg);
  }
  va_start(ap, zFormat);
  g.zErrMsg = vmprintf(zFormat, ap);
  va_end(ap);
  g.iErrPriority = iPriority;
}
void fossil_error_reset(void){
  free(g.zErrMsg);
  g.zErrMsg = 0;
  g.iErrPriority = 0;
}