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Faster version of patternCompare() that uses new return values rather than

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an extra parameter to communicate wildcard information back up to parent
searches.

FossilOrigin-Name: a1e2b6ce3af690ae91bda3d056357205c4018da7
This commit is contained in:
drh
2016-12-01 18:49:40 +00:00
parent 1a4a73764c
commit 698a01ca2f
3 changed files with 48 additions and 50 deletions
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src/func.c
+40 -39
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@@ -598,9 +598,19 @@ static const struct compareInfo likeInfoNorm = { '%', '_', 0, 1 };
static const struct compareInfo likeInfoAlt = { '%', '_', 0, 0 };
/*
** Compare two UTF-8 strings for equality where the first string can
** potentially be a "glob" or "like" expression. Return true (1) if they
** are the same and false (0) if they are different.
** Possible error returns from patternMatch()
*/
#define SQLITE_MATCH 0
#define SQLITE_NOMATCH 1
#define SQLITE_NOWILDCARDMATCH 2
/*
** Compare two UTF-8 strings for equality where the first string is
** a GLOB or LIKE expression. Return values:
**
** SQLITE_MATCH: Match
** SQLITE_NOMATCH: No match
** SQLITE_NOWILDCARDMATCH: No match in spite of having * or % wildcards.
**
** Globbing rules:
**
@@ -636,8 +646,7 @@ 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 matchOther, /* The escape char (LIKE) or '[' (GLOB) */
int *pbSeenMatchAll /* OUT: True if have seen matchAll */
u32 matchOther /* The escape char (LIKE) or '[' (GLOB) */
){
u32 c, c2; /* Next pattern and input string chars */
u32 matchOne = pInfo->matchOne; /* "?" or "_" */
@@ -650,30 +659,27 @@ static int patternCompare(
/* Skip over multiple "*" characters in the pattern. If there
** are also "?" characters, skip those as well, but consume a
** single character of the input string for each "?" skipped */
*pbSeenMatchAll = 1;
while( (c=Utf8Read(zPattern)) == matchAll || c == matchOne ){
if( c==matchOne && sqlite3Utf8Read(&zString)==0 ){
return 0;
return SQLITE_NOWILDCARDMATCH;
}
}
if( c==0 ){
return 1; /* "*" at the end of the pattern matches */
return SQLITE_MATCH; /* "*" at the end of the pattern matches */
}else if( c==matchOther ){
if( pInfo->matchSet==0 ){
c = sqlite3Utf8Read(&zPattern);
if( c==0 ) return 0;
if( c==0 ) return SQLITE_NOWILDCARDMATCH;
}else{
int bMA = 0; /* True if patternCompare sees matchAll */
/* "[...]" immediately follows the "*". We have to do a slow
** 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,matchOther,&bMA)==0
){
if( bMA ) return 0;
while( *zString ){
int bMatch = patternCompare(&zPattern[-1],zString,pInfo,matchOther);
if( bMatch!=SQLITE_NOMATCH ) return bMatch;
SQLITE_SKIP_UTF8(zString);
}
return *zString!=0;
return SQLITE_NOWILDCARDMATCH;
}
}
@@ -688,7 +694,7 @@ static int patternCompare(
*/
if( c<=0x80 ){
u32 cx;
int bMatchAll = 0;
int bMatch;
if( noCase ){
cx = sqlite3Toupper(c);
c = sqlite3Tolower(c);
@@ -697,34 +703,30 @@ static int patternCompare(
}
while( (c2 = *(zString++))!=0 ){
if( c2!=c && c2!=cx ) continue;
if( patternCompare(zPattern,zString,pInfo,matchOther, &bMatchAll) ){
return 1;
}
if( bMatchAll ) break;
bMatch = patternCompare(zPattern,zString,pInfo,matchOther);
if( bMatch!=SQLITE_NOMATCH ) return bMatch;
}
}else{
int bMatchAll = 0;
int bMatch;
while( (c2 = Utf8Read(zString))!=0 ){
if( c2!=c ) continue;
if( patternCompare(zPattern,zString,pInfo,matchOther, &bMatchAll) ){
return 1;
}
if( bMatchAll ) break;
bMatch = patternCompare(zPattern,zString,pInfo,matchOther);
if( bMatch!=SQLITE_NOMATCH ) return bMatch;
}
}
return 0;
return SQLITE_NOWILDCARDMATCH;
}
if( c==matchOther ){
if( pInfo->matchSet==0 ){
c = sqlite3Utf8Read(&zPattern);
if( c==0 ) return 0;
if( c==0 ) return SQLITE_NOMATCH;
zEscaped = zPattern;
}else{
u32 prior_c = 0;
int seen = 0;
int invert = 0;
c = sqlite3Utf8Read(&zString);
if( c==0 ) return 0;
if( c==0 ) return SQLITE_NOMATCH;
c2 = sqlite3Utf8Read(&zPattern);
if( c2=='^' ){
invert = 1;
@@ -748,7 +750,7 @@ static int patternCompare(
c2 = sqlite3Utf8Read(&zPattern);
}
if( c2==0 || (seen ^ invert)==0 ){
return 0;
return SQLITE_NOMATCH;
}
continue;
}
@@ -759,25 +761,25 @@ static int patternCompare(
continue;
}
if( c==matchOne && zPattern!=zEscaped && c2!=0 ) continue;
return 0;
return SQLITE_NOMATCH;
}
return *zString==0;
return *zString==0 ? SQLITE_MATCH : SQLITE_NOMATCH;
}
/*
** The sqlite3_strglob() interface.
** The sqlite3_strglob() interface. Return 0 on a match (like strcmp()) and
** non-zero if there is no match.
*/
int sqlite3_strglob(const char *zGlobPattern, const char *zString){
int dummy = 0;
return patternCompare((u8*)zGlobPattern, (u8*)zString, &globInfo, '[', &dummy)==0;
return patternCompare((u8*)zGlobPattern, (u8*)zString, &globInfo, '[');
}
/*
** The sqlite3_strlike() interface.
** The sqlite3_strlike() interface. Return 0 on a match and non-zero for
** a miss - like strcmp().
*/
int sqlite3_strlike(const char *zPattern, const char *zStr, unsigned int esc){
int dummy = 0;
return patternCompare((u8*)zPattern, (u8*)zStr, &likeInfoNorm, esc, &dummy)==0;
return patternCompare((u8*)zPattern, (u8*)zStr, &likeInfoNorm, esc);
}
/*
@@ -855,11 +857,10 @@ static void likeFunc(
escape = pInfo->matchSet;
}
if( zA && zB ){
int dummy = 0;
#ifdef SQLITE_TEST
sqlite3_like_count++;
#endif
sqlite3_result_int(context, patternCompare(zB, zA, pInfo, escape, &dummy));
sqlite3_result_int(context, patternCompare(zB, zA, pInfo, escape)==SQLITE_MATCH);
}
}