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owntone-server/sqlext/sqlext.c
ejurgensen 616be4d8cb [db] Use custom LIKE operator adapted from sqlite's icu.c (closes #1390) 
Improves the search, e.g.:
- 'é' LIKE 'e'
- 'æ' LIKE 'Æ'
- 'Ö' LIKE 'o'
2022-02-13 20:52:40 +01:00

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/*
* Copyright (C) 2009-2010 Julien BLACHE <jb@jblache.org>
* Copyright (C) 2010 Kai Elwert <elwertk@googlemail.com>
* Copyright (C) 2022 Espen Jürgensen <espenjurgensen@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
How to test and debug
---------------------
1. Build extension with debug flag
gcc -Wall -g -fPIC -shared sqlext.c -o sqlext.so -lunistring
2. Start sqlite3 in gdb
gdb --args sqlite3
3. Optionally add a breakpoint, and then run sqlite3
b sqlext.c:123
run
4. Load extension and run tests
.load ./sqlext.so
select '01', like('æ', 'Æ') = 1;
select '02', like('o', 'Ö') = 1;
select '03', like('é', 'e') = 1;
select '04', like('O', 'Ø') = 0;
select '05', like('%test\%', 'testx', '\') = 0;
select '06', like('Ö', 'o') = 1;
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <string.h>
#include <stdint.h>
#include <stdlib.h>
#include <inttypes.h>
#include <assert.h>
#include <unistr.h>
#include <unictype.h>
#include <unicase.h>
#include <sqlite3ext.h>
SQLITE_EXTENSION_INIT1
/* ============ Fast Unicode case folding and diacritics removal ============ */
/* The code in this section is copied from sqlite's fts5_unicode.c, */
/* because it is about 4x faster than using libunistring's u32_casefold() */
/*
** If the argument is a codepoint corresponding to a lowercase letter
** in the ASCII range with a diacritic added, return the codepoint
** of the ASCII letter only. For example, if passed 235 - "LATIN
** SMALL LETTER E WITH DIAERESIS" - return 65 ("LATIN SMALL LETTER
** E"). The resuls of passing a codepoint that corresponds to an
** uppercase letter are undefined.
*/
static int fts5_remove_diacritic(int c, int bComplex){
unsigned short aDia[] = {
0, 1797, 1848, 1859, 1891, 1928, 1940, 1995,
2024, 2040, 2060, 2110, 2168, 2206, 2264, 2286,
2344, 2383, 2472, 2488, 2516, 2596, 2668, 2732,
2782, 2842, 2894, 2954, 2984, 3000, 3028, 3336,
3456, 3696, 3712, 3728, 3744, 3766, 3832, 3896,
3912, 3928, 3944, 3968, 4008, 4040, 4056, 4106,
4138, 4170, 4202, 4234, 4266, 4296, 4312, 4344,
4408, 4424, 4442, 4472, 4488, 4504, 6148, 6198,
6264, 6280, 6360, 6429, 6505, 6529, 61448, 61468,
61512, 61534, 61592, 61610, 61642, 61672, 61688, 61704,
61726, 61784, 61800, 61816, 61836, 61880, 61896, 61914,
61948, 61998, 62062, 62122, 62154, 62184, 62200, 62218,
62252, 62302, 62364, 62410, 62442, 62478, 62536, 62554,
62584, 62604, 62640, 62648, 62656, 62664, 62730, 62766,
62830, 62890, 62924, 62974, 63032, 63050, 63082, 63118,
63182, 63242, 63274, 63310, 63368, 63390,
};
#define HIBIT ((unsigned char)0x80)
unsigned char aChar[] = {
'\0', 'a', 'c', 'e', 'i', 'n',
'o', 'u', 'y', 'y', 'a', 'c',
'd', 'e', 'e', 'g', 'h', 'i',
'j', 'k', 'l', 'n', 'o', 'r',
's', 't', 'u', 'u', 'w', 'y',
'z', 'o', 'u', 'a', 'i', 'o',
'u', 'u'|HIBIT, 'a'|HIBIT, 'g', 'k', 'o',
'o'|HIBIT, 'j', 'g', 'n', 'a'|HIBIT, 'a',
'e', 'i', 'o', 'r', 'u', 's',
't', 'h', 'a', 'e', 'o'|HIBIT, 'o',
'o'|HIBIT, 'y', '\0', '\0', '\0', '\0',
'\0', '\0', '\0', '\0', 'a', 'b',
'c'|HIBIT, 'd', 'd', 'e'|HIBIT, 'e', 'e'|HIBIT,
'f', 'g', 'h', 'h', 'i', 'i'|HIBIT,
'k', 'l', 'l'|HIBIT, 'l', 'm', 'n',
'o'|HIBIT, 'p', 'r', 'r'|HIBIT, 'r', 's',
's'|HIBIT, 't', 'u', 'u'|HIBIT, 'v', 'w',
'w', 'x', 'y', 'z', 'h', 't',
'w', 'y', 'a', 'a'|HIBIT, 'a'|HIBIT, 'a'|HIBIT,
'e', 'e'|HIBIT, 'e'|HIBIT, 'i', 'o', 'o'|HIBIT,
'o'|HIBIT, 'o'|HIBIT, 'u', 'u'|HIBIT, 'u'|HIBIT, 'y',
};
unsigned int key = (((unsigned int)c)<<3) | 0x00000007;
int iRes = 0;
int iHi = sizeof(aDia)/sizeof(aDia[0]) - 1;
int iLo = 0;
while( iHi>=iLo ){
int iTest = (iHi + iLo) / 2;
if( key >= aDia[iTest] ){
iRes = iTest;
iLo = iTest+1;
}else{
iHi = iTest-1;
}
}
assert( key>=aDia[iRes] );
if( bComplex==0 && (aChar[iRes] & 0x80) ) return c;
return (c > (aDia[iRes]>>3) + (aDia[iRes]&0x07)) ? c : ((int)aChar[iRes] & 0x7F);
}
/*
** Interpret the argument as a unicode codepoint. If the codepoint
** is an upper case character that has a lower case equivalent,
** return the codepoint corresponding to the lower case version.
** Otherwise, return a copy of the argument.
**
** The results are undefined if the value passed to this function
** is less than zero.
*/
static int sqlite3Fts5UnicodeFold(int c, int eRemoveDiacritic){
/* Each entry in the following array defines a rule for folding a range
** of codepoints to lower case. The rule applies to a range of nRange
** codepoints starting at codepoint iCode.
**
** If the least significant bit in flags is clear, then the rule applies
** to all nRange codepoints (i.e. all nRange codepoints are upper case and
** need to be folded). Or, if it is set, then the rule only applies to
** every second codepoint in the range, starting with codepoint C.
**
** The 7 most significant bits in flags are an index into the aiOff[]
** array. If a specific codepoint C does require folding, then its lower
** case equivalent is ((C + aiOff[flags>>1]) & 0xFFFF).
**
** The contents of this array are generated by parsing the CaseFolding.txt
** file distributed as part of the "Unicode Character Database". See
** http://www.unicode.org for details.
*/
static const struct TableEntry {
unsigned short iCode;
unsigned char flags;
unsigned char nRange;
} aEntry[] = {
{65, 14, 26}, {181, 64, 1}, {192, 14, 23},
{216, 14, 7}, {256, 1, 48}, {306, 1, 6},
{313, 1, 16}, {330, 1, 46}, {376, 116, 1},
{377, 1, 6}, {383, 104, 1}, {385, 50, 1},
{386, 1, 4}, {390, 44, 1}, {391, 0, 1},
{393, 42, 2}, {395, 0, 1}, {398, 32, 1},
{399, 38, 1}, {400, 40, 1}, {401, 0, 1},
{403, 42, 1}, {404, 46, 1}, {406, 52, 1},
{407, 48, 1}, {408, 0, 1}, {412, 52, 1},
{413, 54, 1}, {415, 56, 1}, {416, 1, 6},
{422, 60, 1}, {423, 0, 1}, {425, 60, 1},
{428, 0, 1}, {430, 60, 1}, {431, 0, 1},
{433, 58, 2}, {435, 1, 4}, {439, 62, 1},
{440, 0, 1}, {444, 0, 1}, {452, 2, 1},
{453, 0, 1}, {455, 2, 1}, {456, 0, 1},
{458, 2, 1}, {459, 1, 18}, {478, 1, 18},
{497, 2, 1}, {498, 1, 4}, {502, 122, 1},
{503, 134, 1}, {504, 1, 40}, {544, 110, 1},
{546, 1, 18}, {570, 70, 1}, {571, 0, 1},
{573, 108, 1}, {574, 68, 1}, {577, 0, 1},
{579, 106, 1}, {580, 28, 1}, {581, 30, 1},
{582, 1, 10}, {837, 36, 1}, {880, 1, 4},
{886, 0, 1}, {902, 18, 1}, {904, 16, 3},
{908, 26, 1}, {910, 24, 2}, {913, 14, 17},
{931, 14, 9}, {962, 0, 1}, {975, 4, 1},
{976, 140, 1}, {977, 142, 1}, {981, 146, 1},
{982, 144, 1}, {984, 1, 24}, {1008, 136, 1},
{1009, 138, 1}, {1012, 130, 1}, {1013, 128, 1},
{1015, 0, 1}, {1017, 152, 1}, {1018, 0, 1},
{1021, 110, 3}, {1024, 34, 16}, {1040, 14, 32},
{1120, 1, 34}, {1162, 1, 54}, {1216, 6, 1},
{1217, 1, 14}, {1232, 1, 88}, {1329, 22, 38},
{4256, 66, 38}, {4295, 66, 1}, {4301, 66, 1},
{7680, 1, 150}, {7835, 132, 1}, {7838, 96, 1},
{7840, 1, 96}, {7944, 150, 8}, {7960, 150, 6},
{7976, 150, 8}, {7992, 150, 8}, {8008, 150, 6},
{8025, 151, 8}, {8040, 150, 8}, {8072, 150, 8},
{8088, 150, 8}, {8104, 150, 8}, {8120, 150, 2},
{8122, 126, 2}, {8124, 148, 1}, {8126, 100, 1},
{8136, 124, 4}, {8140, 148, 1}, {8152, 150, 2},
{8154, 120, 2}, {8168, 150, 2}, {8170, 118, 2},
{8172, 152, 1}, {8184, 112, 2}, {8186, 114, 2},
{8188, 148, 1}, {8486, 98, 1}, {8490, 92, 1},
{8491, 94, 1}, {8498, 12, 1}, {8544, 8, 16},
{8579, 0, 1}, {9398, 10, 26}, {11264, 22, 47},
{11360, 0, 1}, {11362, 88, 1}, {11363, 102, 1},
{11364, 90, 1}, {11367, 1, 6}, {11373, 84, 1},
{11374, 86, 1}, {11375, 80, 1}, {11376, 82, 1},
{11378, 0, 1}, {11381, 0, 1}, {11390, 78, 2},
{11392, 1, 100}, {11499, 1, 4}, {11506, 0, 1},
{42560, 1, 46}, {42624, 1, 24}, {42786, 1, 14},
{42802, 1, 62}, {42873, 1, 4}, {42877, 76, 1},
{42878, 1, 10}, {42891, 0, 1}, {42893, 74, 1},
{42896, 1, 4}, {42912, 1, 10}, {42922, 72, 1},
{65313, 14, 26},
};
static const unsigned short aiOff[] = {
1, 2, 8, 15, 16, 26, 28, 32,
37, 38, 40, 48, 63, 64, 69, 71,
79, 80, 116, 202, 203, 205, 206, 207,
209, 210, 211, 213, 214, 217, 218, 219,
775, 7264, 10792, 10795, 23228, 23256, 30204, 54721,
54753, 54754, 54756, 54787, 54793, 54809, 57153, 57274,
57921, 58019, 58363, 61722, 65268, 65341, 65373, 65406,
65408, 65410, 65415, 65424, 65436, 65439, 65450, 65462,
65472, 65476, 65478, 65480, 65482, 65488, 65506, 65511,
65514, 65521, 65527, 65528, 65529,
};
int ret = c;
assert( sizeof(unsigned short)==2 && sizeof(unsigned char)==1 );
if( c<128 ){
if( c>='A' && c<='Z' ) ret = c + ('a' - 'A');
}else if( c<65536 ){
const struct TableEntry *p;
int iHi = sizeof(aEntry)/sizeof(aEntry[0]) - 1;
int iLo = 0;
int iRes = -1;
assert( c>aEntry[0].iCode );
while( iHi>=iLo ){
int iTest = (iHi + iLo) / 2;
int cmp = (c - aEntry[iTest].iCode);
if( cmp>=0 ){
iRes = iTest;
iLo = iTest+1;
}else{
iHi = iTest-1;
}
}
assert( iRes>=0 && c>=aEntry[iRes].iCode );
p = &aEntry[iRes];
if( c<(p->iCode + p->nRange) && 0==(0x01 & p->flags & (p->iCode ^ c)) ){
ret = (c + (aiOff[p->flags>>1])) & 0x0000FFFF;
assert( ret>0 );
}
if( eRemoveDiacritic ){
ret = fts5_remove_diacritic(ret, eRemoveDiacritic==2);
}
}
else if( c>=66560 && c<66600 ){
ret = c + 40;
}
return ret;
}
/* ========================= Custom LIKE function =========================== */
/* The code in this section is copied from sqlite's icu.c, but instead of */
/* libicu it is modified to use the above, plus a bit of libunistring */
/*
** Maximum length (in bytes) of the pattern in a LIKE or GLOB
** operator.
*/
#ifndef SQLITE_MAX_LIKE_PATTERN_LENGTH
# define SQLITE_MAX_LIKE_PATTERN_LENGTH 50000
#endif
// Not defined in Debian Buster's version of SQLite
#ifdef SQLITE_INNOCUOUS
# define SQLITEICU_EXTRAFLAGS (SQLITE_DETERMINISTIC|SQLITE_INNOCUOUS)
#else
# define SQLITEICU_EXTRAFLAGS SQLITE_DETERMINISTIC
#endif
/*
** This lookup table is used to help decode the first byte of
** a multi-byte UTF8 character. It is copied here from SQLite source
** code file utf8.c.
*/
static const unsigned char icuUtf8Trans1[] = {
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x00, 0x00,
};
#define SQLITE_ICU_READ_UTF8(zIn, c) \
c = *(zIn++); \
if( c>=0xc0 ){ \
c = icuUtf8Trans1[c-0xc0]; \
while( (*zIn & 0xc0)==0x80 ){ \
c = (c<<6) + (0x3f & *(zIn++)); \
} \
}
#define SQLITE_ICU_SKIP_UTF8(zIn) \
assert( *zIn ); \
if( *(zIn++)>=0xc0 ){ \
while( (*zIn & 0xc0)==0x80 ){zIn++;} \
}
/*
** Compare two UTF-8 strings for equality where the first string is
** a "LIKE" expression. Return true (1) if they are the same and
** false (0) if they are different.
*/
static int icuLikeCompare(
const uint8_t *zPattern, /* LIKE pattern */
const uint8_t *zString, /* The UTF-8 string to compare against */
const uint32_t uEsc /* The escape character */
){
static const uint32_t MATCH_ONE = (uint32_t)'_';
static const uint32_t MATCH_ALL = (uint32_t)'%';
int prevEscape = 0; /* True if the previous character was uEsc */
while( 1 ){
/* Read (and consume) the next character from the input pattern. */
uint32_t uPattern;
SQLITE_ICU_READ_UTF8(zPattern, uPattern);
if( uPattern==0 ) break;
/* There are now 4 possibilities:
**
** 1. uPattern is an unescaped match-all character "%",
** 2. uPattern is an unescaped match-one character "_",
** 3. uPattern is an unescaped escape character, or
** 4. uPattern is to be handled as an ordinary character
*/
if( uPattern==MATCH_ALL && !prevEscape && uPattern!=uEsc ){
/* Case 1. */
uint8_t c;
/* Skip any MATCH_ALL or MATCH_ONE characters that follow a
** MATCH_ALL. For each MATCH_ONE, skip one character in the
** test string.
*/
while( (c=*zPattern) == MATCH_ALL || c == MATCH_ONE ){
if( c==MATCH_ONE ){
if( *zString==0 ) return 0;
SQLITE_ICU_SKIP_UTF8(zString);
}
zPattern++;
}
if( *zPattern==0 ) return 1;
while( *zString ){
if( icuLikeCompare(zPattern, zString, uEsc) ){
return 1;
}
SQLITE_ICU_SKIP_UTF8(zString);
}
return 0;
}else if( uPattern==MATCH_ONE && !prevEscape && uPattern!=uEsc ){
/* Case 2. */
if( *zString==0 ) return 0;
SQLITE_ICU_SKIP_UTF8(zString);
}else if( uPattern==uEsc && !prevEscape ){
/* Case 3. */
prevEscape = 1;
}else{
/* Case 4. */
uint32_t uString;
SQLITE_ICU_READ_UTF8(zString, uString);
if( sqlite3Fts5UnicodeFold(uString, 1) != sqlite3Fts5UnicodeFold(uPattern, 1) )
{
return 0;
}
prevEscape = 0;
}
}
return *zString==0;
}
/*
** Implementation of the like() SQL function. This function implements
** the build-in LIKE operator. The first argument to the function is the
** pattern and the second argument is the string. So, the SQL statements:
**
** A LIKE B
**
** is implemented as like(B, A). If there is an escape character E,
**
** A LIKE B ESCAPE E
**
** is mapped to like(B, A, E).
*/
static void icuLikeFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
const unsigned char *zA = sqlite3_value_text(argv[0]);
const unsigned char *zB = sqlite3_value_text(argv[1]);
uint32_t uEsc = 0;
/* Limit the length of the LIKE or GLOB pattern to avoid problems
** of deep recursion and N*N behavior in patternCompare().
*/
if( sqlite3_value_bytes(argv[0])>SQLITE_MAX_LIKE_PATTERN_LENGTH ){
sqlite3_result_error(context, "LIKE or GLOB pattern too complex", -1);
return;
}
if( argc==3 ){
/* The escape character string must consist of a single UTF-8 character.
** Otherwise, return an error.
*/
int nE= sqlite3_value_bytes(argv[2]);
const unsigned char *zE = sqlite3_value_text(argv[2]);
if( zE==0 ) return;
/* Extract first utf-8 character */
ucs4_t uc;
if( u8_mbtoucr(&uc, zE, nE) != nE || u32_uctomb(&uEsc, uc, 1) < 0 ){
sqlite3_result_error(context,
"ESCAPE expression must be a single character", -1);
return;
}
}
if( zA && zB ){
sqlite3_result_int(context, icuLikeCompare(zA, zB, uEsc));
}
}
/* ================== Other custom functions/collations ===================== */
static void
daap_no_zero_xfunc(sqlite3_context *pv, int n, sqlite3_value **ppv)
{
sqlite3_int64 new_value;
sqlite3_int64 old_value;
if (n != 2)
{
sqlite3_result_error(pv, "daap_no_zero() requires 2 parameters, new_value and old_value", -1);
return;
}
if ((sqlite3_value_type(ppv[0]) != SQLITE_INTEGER)
|| (sqlite3_value_type(ppv[1]) != SQLITE_INTEGER))
{
sqlite3_result_error(pv, "daap_no_zero() requires 2 integer parameters", -1);
return;
}
new_value = sqlite3_value_int64(ppv[0]);
old_value = sqlite3_value_int64(ppv[1]);
if (new_value != 0)
sqlite3_result_int64(pv, new_value);
else
sqlite3_result_int64(pv, old_value);
}
static int
daap_unicode_xcollation(void *notused, int llen, const void *left, int rlen, const void *right)
{
ucs4_t lch;
ucs4_t rch;
int lalpha;
int ralpha;
int rpp;
int ret;
/* Extract first utf-8 character */
ret = u8_mbtoucr(&lch, (const uint8_t *)left, llen);
if (ret < 0)
return 0;
ret = u8_mbtoucr(&rch, (const uint8_t *)right, rlen);
if (ret < 0)
return 0;
/* Ensure digits and other non-alphanum sort to tail */
lalpha = uc_is_alpha(lch);
ralpha = uc_is_alpha(rch);
if (!lalpha && ralpha)
return 1;
else if (lalpha && !ralpha)
return -1;
/* Compare case and normalization insensitive */
ret = u8_casecmp((const uint8_t *)left, llen, (const uint8_t*)right, rlen, NULL, UNINORM_NFD, &rpp);
if (ret < 0)
return 0;
return rpp;
}
int
sqlite3_extension_init(sqlite3 *db, char **pzErrMsg, const sqlite3_api_routines *pApi)
{
SQLITE_EXTENSION_INIT2(pApi);
const char *errmsg = NULL;
int ret;
ret = sqlite3_create_function(db, "like", 2, SQLITE_UTF8|SQLITEICU_EXTRAFLAGS, NULL, icuLikeFunc, NULL, NULL);
if (ret != SQLITE_OK)
{
errmsg = "Could not create custom LIKE function (non-escaped)";
goto error;
}
ret = sqlite3_create_function(db, "like", 3, SQLITE_UTF8|SQLITEICU_EXTRAFLAGS, NULL, icuLikeFunc, NULL, NULL);
if (ret != SQLITE_OK)
{
errmsg = "Could not create custom LIKE function (escaped)";
goto error;
}
ret = sqlite3_create_function(db, "daap_no_zero", 2, SQLITE_UTF8, NULL, daap_no_zero_xfunc, NULL, NULL);
if (ret != SQLITE_OK)
{
errmsg = "Could not create daap_no_zero function";
goto error;
}
ret = sqlite3_create_collation(db, "DAAP", SQLITE_UTF8, NULL, daap_unicode_xcollation);
if (ret != SQLITE_OK)
{
errmsg = "Could not create sqlite3 custom collation DAAP";
goto error;
}
return 0;
error:
if (pzErrMsg)
*pzErrMsg = sqlite3_mprintf("%s: %s\n", errmsg, sqlite3_errmsg(db));
return -1;
}
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