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Slightly smaller and faster LIKE/GLOB comparison implementation.

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FossilOrigin-Name: 5dddcc78eec5bcd0c7e8fe1b70875ce775488f0c
This commit is contained in:
drh
2016-01-11 03:48:18 +00:00
parent a829992969
commit 07e8347221
3 changed files with 22 additions and 29 deletions
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37
src/func.c
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@@ -567,10 +567,10 @@ static void total_changes(
** A structure defining how to do GLOB-style comparisons.
*/
struct compareInfo {
u8 matchAll;
u8 matchOne;
u8 matchSet;
u8 noCase;
u8 matchAll; /* "*" or "%" */
u8 matchOne; /* "?" or "_" */
u8 matchSet; /* "[" or 0 */
u8 noCase; /* true to ignore case differences */
};
/*
@@ -633,22 +633,14 @@ static int patternCompare(
const u8 *zPattern, /* The glob pattern */
const u8 *zString, /* The string to compare against the glob */
const struct compareInfo *pInfo, /* Information about how to do the compare */
u32 esc /* The escape character */
u32 matchOther /* The escape char (LIKE) or '[' (GLOB) */
){
u32 c, c2; /* Next pattern and input string chars */
u32 matchOne = pInfo->matchOne; /* "?" or "_" */
u32 matchAll = pInfo->matchAll; /* "*" or "%" */
u32 matchOther; /* "[" or the escape character */
u8 noCase = pInfo->noCase; /* True if uppercase==lowercase */
const u8 *zEscaped = 0; /* One past the last escaped input char */
/* The GLOB operator does not have an ESCAPE clause. And LIKE does not
** have the matchSet operator. So we either have to look for one or
** the other, never both. Hence the single variable matchOther is used
** to store the one we have to look for.
*/
matchOther = esc ? esc : pInfo->matchSet;
while( (c = Utf8Read(zPattern))!=0 ){
if( c==matchAll ){ /* Match "*" */
/* Skip over multiple "*" characters in the pattern. If there
@@ -662,7 +654,7 @@ static int patternCompare(
if( c==0 ){
return 1; /* "*" at the end of the pattern matches */
}else if( c==matchOther ){
if( esc ){
if( pInfo->matchSet==0 ){
c = sqlite3Utf8Read(&zPattern);
if( c==0 ) return 0;
}else{
@@ -670,7 +662,7 @@ static int patternCompare(
** recursive search in this case, but it is an unusual case. */
assert( matchOther<0x80 ); /* '[' is a single-byte character */
while( *zString
&& patternCompare(&zPattern[-1],zString,pInfo,esc)==0 ){
&& patternCompare(&zPattern[-1],zString,pInfo,matchOther)==0 ){
SQLITE_SKIP_UTF8(zString);
}
return *zString!=0;
@@ -696,18 +688,18 @@ static int patternCompare(
}
while( (c2 = *(zString++))!=0 ){
if( c2!=c && c2!=cx ) continue;
if( patternCompare(zPattern,zString,pInfo,esc) ) return 1;
if( patternCompare(zPattern,zString,pInfo,matchOther) ) return 1;
}
}else{
while( (c2 = Utf8Read(zString))!=0 ){
if( c2!=c ) continue;
if( patternCompare(zPattern,zString,pInfo,esc) ) return 1;
if( patternCompare(zPattern,zString,pInfo,matchOther) ) return 1;
}
}
return 0;
}
if( c==matchOther ){
if( esc ){
if( pInfo->matchSet==0 ){
c = sqlite3Utf8Read(&zPattern);
if( c==0 ) return 0;
zEscaped = zPattern;
@@ -760,7 +752,7 @@ static int patternCompare(
** The sqlite3_strglob() interface.
*/
int sqlite3_strglob(const char *zGlobPattern, const char *zString){
return patternCompare((u8*)zGlobPattern, (u8*)zString, &globInfo, 0)==0;
return patternCompare((u8*)zGlobPattern, (u8*)zString, &globInfo, '[')==0;
}
/*
@@ -798,9 +790,10 @@ static void likeFunc(
sqlite3_value **argv
){
const unsigned char *zA, *zB;
u32 escape = 0;
u32 escape;
int nPat;
sqlite3 *db = sqlite3_context_db_handle(context);
struct compareInfo *pInfo = sqlite3_user_data(context);
#ifdef SQLITE_LIKE_DOESNT_MATCH_BLOBS
if( sqlite3_value_type(argv[0])==SQLITE_BLOB
@@ -840,13 +833,13 @@ static void likeFunc(
return;
}
escape = sqlite3Utf8Read(&zEsc);
}else{
escape = pInfo->matchSet;
}
if( zA && zB ){
struct compareInfo *pInfo = sqlite3_user_data(context);
#ifdef SQLITE_TEST
sqlite3_like_count++;
#endif
sqlite3_result_int(context, patternCompare(zB, zA, pInfo, escape));
}
}