SHA1 Hash:	b816fadfc76c2e7b00da9ed2c23a8dfdddd6a7b8
Date:	2007-09-05 18:46:59
User:	drh
Comment:	Fix pathological N*2 behavior in the delta generator.
Timelines:	ancestors | descendants | both | trunk
Other Links:	files | ZIP archive | manifest

• branch=trunk inherited from [a28c83647d]
• sym-trunk inherited from [a28c83647d]

Modified src/delta.c from [4f6e9c70e9] to [d84dda2bcd].

@@ -340,15 +340,16 @@
     hash_init(&h, &zOut[base]);
     i = 0;     /* Trying to match a landmark against zOut[base+i] */
     bestCnt = 0;
     while( 1 ){
       int hv;
+      int limit = 50;
 
       hv = hash_32bit(&h) & (MX_LANDMARK-1);
       DEBUG2( printf("LOOKING: %4d [%s]\n", base+i, print16(&zOut[base+i])); )
       iBlock = landmark[hv];
-      while( iBlock>=0 ){
+      while( iBlock>=0 && (limit--)>0 ){
         /*
         ** The hash window has identified a potential match against
         ** landmark block iBlock.  But we need to investigate further.
         **
         ** Look for a region in zOut that matches zSrc. Anchor the search
@@ -404,11 +405,11 @@
       }
 
       /* We have a copy command that does not cause the delta to be larger
       ** than a literal insert.  So add the copy command to the delta.
       */
-      if( bestCnt>0 && base+i>=bestOfst+NHASH ){
+      if( bestCnt>0 ){
         if( bestLitsz>0 ){
           /* Add an insert command before the copy */
           putInt(bestLitsz,&zDelta);
           *(zDelta++) = ':';
           memcpy(zDelta, &zOut[base], bestLitsz);

Deleted test/basic1.test version [d90e14fae8]