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d3a156caf5
A common complain with libSQL is how to run extensions. The main mechanism, with a .so, has a lot of issues around how those .so are distributed. The most common extensions are the ones in the sqlean package. We can improve this experience by bundling them in our sqlite build. Not all SQLean extensions are kosher: some of them, like fileio, use the vfs. Others, are deemed too complex. The extensions included here are a subset that we deem important enough, and low risk enough, to just be a part of the main bundle.
88 lines
2.5 KiB
C
88 lines
2.5 KiB
C
// Ooriginally from the spellfix SQLite exension, Public Domain
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// https://www.sqlite.org/src/file/ext/misc/spellfix.c
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// Modified by Anton Zhiyanov, https://github.com/nalgeon/sqlean/, MIT License
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#include <assert.h>
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#include <stdlib.h>
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#include "fuzzy/common.h"
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extern const unsigned char midClass[];
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extern const unsigned char initClass[];
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extern const unsigned char className[];
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/*
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** Generate a "phonetic hash" from a string of ASCII characters
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** in zIn[0..nIn-1].
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**
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** * Map characters by character class as defined above.
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** * Omit double-letters
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** * Omit vowels beside R and L
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** * Omit T when followed by CH
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** * Omit W when followed by R
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** * Omit D when followed by J or G
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** * Omit K in KN or G in GN at the beginning of a word
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**
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** Space to hold the result is obtained from sqlite3_malloc()
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**
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** Return NULL if memory allocation fails.
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*/
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unsigned char* phonetic_hash(const unsigned char* zIn, int nIn) {
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unsigned char* zOut = malloc(nIn + 1);
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int i;
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int nOut = 0;
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char cPrev = 0x77;
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char cPrevX = 0x77;
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const unsigned char* aClass = initClass;
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if (zOut == 0)
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return 0;
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if (nIn > 2) {
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switch (zIn[0]) {
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case 'g':
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case 'k': {
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if (zIn[1] == 'n') {
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zIn++;
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nIn--;
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}
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break;
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}
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}
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}
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for (i = 0; i < nIn; i++) {
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unsigned char c = zIn[i];
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if (i + 1 < nIn) {
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if (c == 'w' && zIn[i + 1] == 'r')
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continue;
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if (c == 'd' && (zIn[i + 1] == 'j' || zIn[i + 1] == 'g'))
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continue;
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if (i + 2 < nIn) {
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if (c == 't' && zIn[i + 1] == 'c' && zIn[i + 2] == 'h')
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continue;
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}
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}
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c = aClass[c & 0x7f];
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if (c == CCLASS_SPACE)
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continue;
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if (c == CCLASS_OTHER && cPrev != CCLASS_DIGIT)
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continue;
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aClass = midClass;
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if (c == CCLASS_VOWEL && (cPrevX == CCLASS_R || cPrevX == CCLASS_L)) {
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continue; /* No vowels beside L or R */
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}
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if ((c == CCLASS_R || c == CCLASS_L) && cPrevX == CCLASS_VOWEL) {
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nOut--; /* No vowels beside L or R */
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}
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cPrev = c;
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if (c == CCLASS_SILENT)
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continue;
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cPrevX = c;
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c = className[c];
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assert(nOut >= 0);
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if (nOut == 0 || c != zOut[nOut - 1])
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zOut[nOut++] = c;
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}
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zOut[nOut] = 0;
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return zOut;
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}
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