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Overview
| Comment: | Tweaks to the keyword hash generator. Tried to make it a little faster. If nothing else, the keyword hash table is now a little smaller. (CVS 2297) |
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| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: | 4eca6c05abdf3955c5fd7bd3a22c87cd |
| User & Date: | drh 2005-02-01 01:40:44 |
Context
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2005-02-01
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| 02:13 | Change to sqlite3AffinityType() to remove hex constants. (CVS 2298) check-in: d8b4b0ef user: danielk1977 tags: trunk | |
| 01:40 | Tweaks to the keyword hash generator. Tried to make it a little faster. If nothing else, the keyword hash table is now a little smaller. (CVS 2297) check-in: 4eca6c05 user: drh tags: trunk | |
| 01:21 | Replace sqlite3AffinityType() with a slightly faster version. (CVS 2296) check-in: abe9f5e8 user: danielk1977 tags: trunk | |
Changes
Changes to tool/mkkeywordhash.c.
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}
NKEYWORD = j;
/* Fill in the lengths of strings and hashes for all entries. */
for(i=0; i<NKEYWORD; i++){
Keyword *p = &aKeywordTable[i];
p->len = strlen(p->zName);
p->hash = UpperToLower[p->zName[0]]*5 +
UpperToLower[p->zName[p->len-1]]*3 + p->len;
p->id = i+1;
}
/* Sort the table from shortest to longest keyword */
qsort(aKeywordTable, NKEYWORD, sizeof(aKeywordTable[0]), keywordCompare1);
/* Look for short keywords embedded in longer keywords */
................................................................................
for(i=0; i<NKEYWORD; i++){
h = aKeywordTable[i].hash % bestSize;
aKeywordTable[i].iNext = aHash[h];
aHash[h] = i+1;
}
/* Begin generating code */
printf("static int keywordCode(const char *z, int n){\n");
printf(" static const char zText[%d] =\n", nChar+1);
for(i=j=0; i<NKEYWORD; i++){
Keyword *p = &aKeywordTable[i];
if( p->substrId ) continue;
if( j==0 ) printf(" \"");
................................................................................
j = 0;
}
}
printf("%s };\n", j==0 ? "" : "\n");
printf(" int h, i;\n");
printf(" if( n<2 ) return TK_ID;\n");
printf(" h = (sqlite3UpperToLower[((unsigned char*)z)[0]]*5 + \n"
" sqlite3UpperToLower[((unsigned char*)z)[n-1]]*3 +\n"
" n) %% %d;\n", bestSize);
printf(" for(i=((int)aHash[h])-1; i>=0; i=((int)aNext[i])-1){\n");
printf(" if( aLen[i]==n &&"
" sqlite3StrNICmp(&zText[aOffset[i]],z,n)==0 ){\n");
printf(" return aCode[i];\n");
printf(" }\n");
printf(" }\n");
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315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 ... 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 ... 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 |
}
NKEYWORD = j;
/* Fill in the lengths of strings and hashes for all entries. */
for(i=0; i<NKEYWORD; i++){
Keyword *p = &aKeywordTable[i];
p->len = strlen(p->zName);
p->hash = (UpperToLower[p->zName[0]]*4) ^
(UpperToLower[p->zName[p->len-1]]*3) ^ p->len;
p->id = i+1;
}
/* Sort the table from shortest to longest keyword */
qsort(aKeywordTable, NKEYWORD, sizeof(aKeywordTable[0]), keywordCompare1);
/* Look for short keywords embedded in longer keywords */
................................................................................
for(i=0; i<NKEYWORD; i++){
h = aKeywordTable[i].hash % bestSize;
aKeywordTable[i].iNext = aHash[h];
aHash[h] = i+1;
}
/* Begin generating code */
printf("/* Hash score: %d */\n", bestCount);
printf("static int keywordCode(const char *z, int n){\n");
printf(" static const char zText[%d] =\n", nChar+1);
for(i=j=0; i<NKEYWORD; i++){
Keyword *p = &aKeywordTable[i];
if( p->substrId ) continue;
if( j==0 ) printf(" \"");
................................................................................
j = 0;
}
}
printf("%s };\n", j==0 ? "" : "\n");
printf(" int h, i;\n");
printf(" if( n<2 ) return TK_ID;\n");
printf(" h = ((sqlite3UpperToLower[((unsigned char*)z)[0]]*4) ^\n"
" (sqlite3UpperToLower[((unsigned char*)z)[n-1]]*3) ^\n"
" n) %% %d;\n", bestSize);
printf(" for(i=((int)aHash[h])-1; i>=0; i=((int)aNext[i])-1){\n");
printf(" if( aLen[i]==n &&"
" sqlite3StrNICmp(&zText[aOffset[i]],z,n)==0 ){\n");
printf(" return aCode[i];\n");
printf(" }\n");
printf(" }\n");
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