return zDelta - zOrigDelta;
  }

  /* Compute the hash table used to locate matching sections in the
  ** source file.
  */
  nHash = lenSrc/NHASH;
  collide = malloc( nHash*2*sizeof(int) );
  collide = fossil_malloc( nHash*2*sizeof(int) );
  if( collide==0 ) return -1;
  landmark = &collide[nHash];
  memset(landmark, -1, nHash*sizeof(int));
  memset(collide, -1, nHash*sizeof(int));
  for(i=0; i<lenSrc-NHASH; i+=NHASH){
    int hv;
    hash_init(&h, &zSrc[i]);
    hv = hash_32bit(&h) % nHash;