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Overview
Comment:Change the (machine-generated) keywordhash.h file to increase the scope of the tables used for keyword matching, so that the tables are accessible to functions other then keywordCode().
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SHA3-256: c5ed5ebdf660501fde7cc8aefaaaeae2a68e5899a64ac93f26684842a235281d
User & Date: drh 2017-07-06 16:33:14
Context
2017-07-06
22:43
Small adjustment to main.mk that facilitates giving non-standard compile-time options to the shell. check-in: 7c7d53a9 user: drh tags: trunk
17:36
Initial implementation of a highly experimental interface for listing all keywords and symbolic names for an SQLite database connection. check-in: 04ef6783 user: drh tags: experimental-namelist
16:33
Change the (machine-generated) keywordhash.h file to increase the scope of the tables used for keyword matching, so that the tables are accessible to functions other then keywordCode(). check-in: c5ed5ebd user: drh tags: trunk
13:51
More compact implementation of the typeof() SQL function. check-in: efb4aab0 user: drh tags: trunk
Changes
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Changes to tool/mkkeywordhash.c.

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*/
int main(int argc, char **argv){
  int i, j, k, h;
  int bestSize, bestCount;
  int count;
  int nChar;
  int totalLen = 0;
  int aHash[1000];  /* 1000 is much bigger than nKeyword */
  char zText[2000];

  /* Remove entries from the list of keywords that have mask==0 */
  for(i=j=0; i<nKeyword; i++){
    if( aKeywordTable[i].mask==0 ) continue;
    if( j<i ){
      aKeywordTable[j] = aKeywordTable[i];
    }
................................................................................
  qsort(aKeywordTable, nKeyword, sizeof(aKeywordTable[0]), keywordCompare3);

  /* Figure out how big to make the hash table in order to minimize the
  ** number of collisions */
  bestSize = nKeyword;
  bestCount = nKeyword*nKeyword;
  for(i=nKeyword/2; i<=2*nKeyword; i++){
    for(j=0; j<i; j++) aHash[j] = 0;
    for(j=0; j<nKeyword; j++){
      h = aKeywordTable[j].hash % i;
      aHash[h] *= 2;
      aHash[h]++;
    }
    for(j=count=0; j<i; j++) count += aHash[j];
    if( count<bestCount ){
      bestCount = count;
      bestSize = i;
    }
  }

  /* Compute the hash */
  for(i=0; i<bestSize; i++) aHash[i] = 0;
  for(i=0; i<nKeyword; i++){
    h = aKeywordTable[i].hash % bestSize;
    aKeywordTable[i].iNext = aHash[h];
    aHash[h] = i+1;
  }

  /* Begin generating code */
  printf("%s", zHdr);
  printf("/* Hash score: %d */\n", bestCount);
  printf("static int keywordCode(const char *z, int n, int *pType){\n");
  printf("  /* zText[] encodes %d bytes of keywords in %d bytes */\n",
          totalLen + nKeyword, nChar+1 );
  for(i=j=k=0; i<nKeyword; i++){
    Keyword *p = &aKeywordTable[i];
    if( p->substrId ) continue;
    memcpy(&zText[k], p->zName, p->len);
    k += p->len;
    if( j+p->len>70 ){
      printf("%*s */\n", 74-j, "");
      j = 0;
    }
    if( j==0 ){
      printf("  /*   ");
      j = 8;
    }
    printf("%s", p->zName);
    j += p->len;
  }
  if( j>0 ){
    printf("%*s */\n", 74-j, "");
  }
  printf("  static const char zText[%d] = {\n", nChar);
  zText[nChar] = 0;
  for(i=j=0; i<k; i++){
    if( j==0 ){
      printf("    ");
    }
    if( zText[i]==0 ){
      printf("0");
    }else{
      printf("'%c',", zText[i]);
    }
    j += 4;
    if( j>68 ){
      printf("\n");
      j = 0;
    }
  }
  if( j>0 ) printf("\n");
  printf("  };\n");


  printf("  static const unsigned char aHash[%d] = {\n", bestSize);
  for(i=j=0; i<bestSize; i++){
    if( j==0 ) printf("    ");
    printf(" %3d,", aHash[i]);
    j++;
    if( j>12 ){
      printf("\n");
      j = 0;
    }
  }
  printf("%s  };\n", j==0 ? "" : "\n");    




  printf("  static const unsigned char aNext[%d] = {\n", nKeyword);
  for(i=j=0; i<nKeyword; i++){
    if( j==0 ) printf("    ");
    printf(" %3d,", aKeywordTable[i].iNext);
    j++;
    if( j>12 ){
      printf("\n");
      j = 0;
    }
  }
  printf("%s  };\n", j==0 ? "" : "\n");    


  printf("  static const unsigned char aLen[%d] = {\n", nKeyword);
  for(i=j=0; i<nKeyword; i++){
    if( j==0 ) printf("    ");
    printf(" %3d,", aKeywordTable[i].len+aKeywordTable[i].prefix);
    j++;
    if( j>12 ){
      printf("\n");
      j = 0;
    }
  }
  printf("%s  };\n", j==0 ? "" : "\n");    



  printf("  static const unsigned short int aOffset[%d] = {\n", nKeyword);
  for(i=j=0; i<nKeyword; i++){
    if( j==0 ) printf("    ");
    printf(" %3d,", aKeywordTable[i].offset);
    j++;
    if( j>12 ){
      printf("\n");
      j = 0;
    }
  }
  printf("%s  };\n", j==0 ? "" : "\n");


  printf("  static const unsigned char aCode[%d] = {\n", nKeyword);
  for(i=j=0; i<nKeyword; i++){
    char *zToken = aKeywordTable[i].zTokenType;
    if( j==0 ) printf("    ");
    printf("%s,%*s", zToken, (int)(14-strlen(zToken)), "");
    j++;
    if( j>=5 ){
      printf("\n");
      j = 0;
    }
  }
  printf("%s  };\n", j==0 ? "" : "\n");





  printf("  int i, j;\n");
  printf("  const char *zKW;\n");
  printf("  if( n>=2 ){\n");
  printf("    i = ((charMap(z[0])*4) ^ (charMap(z[n-1])*3) ^ n) %% %d;\n",
          bestSize);
  printf("    for(i=((int)aHash[i])-1; i>=0; i=((int)aNext[i])-1){\n");
  printf("      if( aLen[i]!=n ) continue;\n");
  printf("      j = 0;\n");
  printf("      zKW = &zText[aOffset[i]];\n");
  printf("#ifdef SQLITE_ASCII\n");
  printf("      while( j<n && (z[j]&~0x20)==zKW[j] ){ j++; }\n");
  printf("#endif\n");
  printf("#ifdef SQLITE_EBCDIC\n");
  printf("      while( j<n && toupper(z[j])==zKW[j] ){ j++; }\n");
  printf("#endif\n");
  printf("      if( j<n ) continue;\n");
  for(i=0; i<nKeyword; i++){
    printf("      testcase( i==%d ); /* %s */\n",
           i, aKeywordTable[i].zOrigName);
  }
  printf("      *pType = aCode[i];\n");
  printf("      break;\n");
  printf("    }\n");
  printf("  }\n");
  printf("  return n;\n");
  printf("}\n");
  printf("int sqlite3KeywordCode(const unsigned char *z, int n){\n");
  printf("  int id = TK_ID;\n");







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*/
int main(int argc, char **argv){
  int i, j, k, h;
  int bestSize, bestCount;
  int count;
  int nChar;
  int totalLen = 0;
  int aKWHash[1000];  /* 1000 is much bigger than nKeyword */
  char zKWText[2000];

  /* Remove entries from the list of keywords that have mask==0 */
  for(i=j=0; i<nKeyword; i++){
    if( aKeywordTable[i].mask==0 ) continue;
    if( j<i ){
      aKeywordTable[j] = aKeywordTable[i];
    }
................................................................................
  qsort(aKeywordTable, nKeyword, sizeof(aKeywordTable[0]), keywordCompare3);

  /* Figure out how big to make the hash table in order to minimize the
  ** number of collisions */
  bestSize = nKeyword;
  bestCount = nKeyword*nKeyword;
  for(i=nKeyword/2; i<=2*nKeyword; i++){
    for(j=0; j<i; j++) aKWHash[j] = 0;
    for(j=0; j<nKeyword; j++){
      h = aKeywordTable[j].hash % i;
      aKWHash[h] *= 2;
      aKWHash[h]++;
    }
    for(j=count=0; j<i; j++) count += aKWHash[j];
    if( count<bestCount ){
      bestCount = count;
      bestSize = i;
    }
  }

  /* Compute the hash */
  for(i=0; i<bestSize; i++) aKWHash[i] = 0;
  for(i=0; i<nKeyword; i++){
    h = aKeywordTable[i].hash % bestSize;
    aKeywordTable[i].iNext = aKWHash[h];
    aKWHash[h] = i+1;
  }

  /* Begin generating code */
  printf("%s", zHdr);
  printf("/* Hash score: %d */\n", bestCount);

  printf("/* zKWText[] encodes %d bytes of keyword text in %d bytes */\n",
          totalLen + nKeyword, nChar+1 );
  for(i=j=k=0; i<nKeyword; i++){
    Keyword *p = &aKeywordTable[i];
    if( p->substrId ) continue;
    memcpy(&zKWText[k], p->zName, p->len);
    k += p->len;
    if( j+p->len>70 ){
      printf("%*s */\n", 74-j, "");
      j = 0;
    }
    if( j==0 ){
      printf("/*   ");
      j = 8;
    }
    printf("%s", p->zName);
    j += p->len;
  }
  if( j>0 ){
    printf("%*s */\n", 74-j, "");
  }
  printf("static const char zKWText[%d] = {\n", nChar);
  zKWText[nChar] = 0;
  for(i=j=0; i<k; i++){
    if( j==0 ){
      printf("  ");
    }
    if( zKWText[i]==0 ){
      printf("0");
    }else{
      printf("'%c',", zKWText[i]);
    }
    j += 4;
    if( j>68 ){
      printf("\n");
      j = 0;
    }
  }
  if( j>0 ) printf("\n");
  printf("};\n");

  printf("/* aKWHash[i] is the hash value for the i-th keyword */\n");
  printf("static const unsigned char aKWHash[%d] = {\n", bestSize);
  for(i=j=0; i<bestSize; i++){
    if( j==0 ) printf("  ");
    printf(" %3d,", aKWHash[i]);
    j++;
    if( j>12 ){
      printf("\n");
      j = 0;
    }
  }
  printf("%s};\n", j==0 ? "" : "\n");    

  printf("/* aKWNext[] forms the hash collision chain.  If aKWHash[i]==0\n");
  printf("** then the i-th keyword has no more hash collisions.  Otherwise,\n");
  printf("** the next keyword with the same hash is aKWHash[i]-1. */\n");
  printf("static const unsigned char aKWNext[%d] = {\n", nKeyword);
  for(i=j=0; i<nKeyword; i++){
    if( j==0 ) printf("  ");
    printf(" %3d,", aKeywordTable[i].iNext);
    j++;
    if( j>12 ){
      printf("\n");
      j = 0;
    }
  }
  printf("%s};\n", j==0 ? "" : "\n");    

  printf("/* aKWLen[i] is the length (in bytes) of the i-th keyword */\n");
  printf("static const unsigned char aKWLen[%d] = {\n", nKeyword);
  for(i=j=0; i<nKeyword; i++){
    if( j==0 ) printf("  ");
    printf(" %3d,", aKeywordTable[i].len+aKeywordTable[i].prefix);
    j++;
    if( j>12 ){
      printf("\n");
      j = 0;
    }
  }
  printf("%s};\n", j==0 ? "" : "\n");    

  printf("/* aKWOffset[i] is the index into zKWText[] of the start of\n");
  printf("** the text for the i-th keyword. */\n");
  printf("static const unsigned short int aKWOffset[%d] = {\n", nKeyword);
  for(i=j=0; i<nKeyword; i++){
    if( j==0 ) printf("  ");
    printf(" %3d,", aKeywordTable[i].offset);
    j++;
    if( j>12 ){
      printf("\n");
      j = 0;
    }
  }
  printf("%s};\n", j==0 ? "" : "\n");

  printf("/* aKWCode[i] is the parser symbol code for the i-th keyword */\n");
  printf("static const unsigned char aKWCode[%d] = {\n", nKeyword);
  for(i=j=0; i<nKeyword; i++){
    char *zToken = aKeywordTable[i].zTokenType;
    if( j==0 ) printf("  ");
    printf("%s,%*s", zToken, (int)(14-strlen(zToken)), "");
    j++;
    if( j>=5 ){
      printf("\n");
      j = 0;
    }
  }
  printf("%s};\n", j==0 ? "" : "\n");

  printf("/* Check to see if z[0..n-1] is a keyword. If it is, write the\n");
  printf("** parser symbol code for that keyword into *pType.  Always\n");
  printf("** return the integer n (the length of the token). */\n");
  printf("static int keywordCode(const char *z, int n, int *pType){\n");
  printf("  int i, j;\n");
  printf("  const char *zKW;\n");
  printf("  if( n>=2 ){\n");
  printf("    i = ((charMap(z[0])*4) ^ (charMap(z[n-1])*3) ^ n) %% %d;\n",
          bestSize);
  printf("    for(i=((int)aKWHash[i])-1; i>=0; i=((int)aKWNext[i])-1){\n");
  printf("      if( aKWLen[i]!=n ) continue;\n");
  printf("      j = 0;\n");
  printf("      zKW = &zKWText[aKWOffset[i]];\n");
  printf("#ifdef SQLITE_ASCII\n");
  printf("      while( j<n && (z[j]&~0x20)==zKW[j] ){ j++; }\n");
  printf("#endif\n");
  printf("#ifdef SQLITE_EBCDIC\n");
  printf("      while( j<n && toupper(z[j])==zKW[j] ){ j++; }\n");
  printf("#endif\n");
  printf("      if( j<n ) continue;\n");
  for(i=0; i<nKeyword; i++){
    printf("      testcase( i==%d ); /* %s */\n",
           i, aKeywordTable[i].zOrigName);
  }
  printf("      *pType = aKWCode[i];\n");
  printf("      break;\n");
  printf("    }\n");
  printf("  }\n");
  printf("  return n;\n");
  printf("}\n");
  printf("int sqlite3KeywordCode(const unsigned char *z, int n){\n");
  printf("  int id = TK_ID;\n");