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Add the ESCAPE clause to the LIKE operator. Not fully tested yet. (CVS 2107)

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FossilOrigin-Name: 49268c2b7a84c4c618214dac8bef0f541440fe6b
This commit is contained in:
danielk1977
2004-11-17 16:41:29 +00:00
parent c7dc75334f
commit 7c6303c042
7 changed files with 216 additions and 23 deletions
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47
src/func.c
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@@ -16,7 +16,7 @@
** sqliteRegisterBuildinFunctions() found at the bottom of the file.
** All other code has file scope.
**
** $Id: func.c,v 1.87 2004/11/14 21:56:30 drh Exp $
** $Id: func.c,v 1.88 2004/11/17 16:41:30 danielk1977 Exp $
*/
#include <ctype.h>
#include <math.h>
@@ -347,10 +347,11 @@ static const struct compareInfo likeInfo = { '%', '_', 0, 1 };
**
** abc[*]xyz Matches "abc*xyz" only
*/
int patternCompare(
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 */
const struct compareInfo *pInfo, /* Information about how to do the compare */
const int esc /* The escape character */
){
register int c;
int invert;
@@ -360,9 +361,10 @@ int patternCompare(
u8 matchAll = pInfo->matchAll;
u8 matchSet = pInfo->matchSet;
u8 noCase = pInfo->noCase;
int prevEscape = 0; /* True if the previous character was 'escape' */
while( (c = *zPattern)!=0 ){
if( c==matchAll ){
if( !prevEscape && c==matchAll ){
while( (c=zPattern[1]) == matchAll || c == matchOne ){
if( c==matchOne ){
if( *zString==0 ) return 0;
@@ -370,9 +372,15 @@ int patternCompare(
}
zPattern++;
}
if( c && sqlite3ReadUtf8(&zPattern[1])==esc ){
u8 const *zTemp = &zPattern[1];
sqliteNextChar(zTemp);
c = *zTemp;
}
if( c==0 ) return 1;
if( c==matchSet ){
while( *zString && patternCompare(&zPattern[1],zString,pInfo)==0 ){
assert( esc==0 ); /* This is GLOB, not LIKE */
while( *zString && patternCompare(&zPattern[1],zString,pInfo,esc)==0 ){
sqliteNextChar(zString);
}
return *zString!=0;
@@ -386,17 +394,18 @@ int patternCompare(
while( c2 != 0 && c2 != c ){ c2 = *++zString; }
}
if( c2==0 ) return 0;
if( patternCompare(&zPattern[1],zString,pInfo) ) return 1;
if( patternCompare(&zPattern[1],zString,pInfo,esc) ) return 1;
sqliteNextChar(zString);
}
return 0;
}
}else if( c==matchOne ){
}else if( !prevEscape && c==matchOne ){
if( *zString==0 ) return 0;
sqliteNextChar(zString);
zPattern++;
}else if( c==matchSet ){
int prior_c = 0;
assert( esc==0 ); /* This only occurs for GLOB, not LIKE */
seen = 0;
invert = 0;
c = sqliteCharVal(zString);
@@ -424,6 +433,9 @@ int patternCompare(
if( c2==0 || (seen ^ invert)==0 ) return 0;
sqliteNextChar(zString);
zPattern++;
}else if( !prevEscape && sqlite3ReadUtf8(zPattern)==esc){
prevEscape = 1;
sqliteNextChar(zPattern);
}else{
if( noCase ){
if( sqlite3UpperToLower[c] != sqlite3UpperToLower[*zString] ) return 0;
@@ -432,6 +444,7 @@ int patternCompare(
}
zPattern++;
zString++;
prevEscape = 0;
}
}
return *zString==0;
@@ -457,8 +470,21 @@ static void likeFunc(
){
const unsigned char *zA = sqlite3_value_text(argv[0]);
const unsigned char *zB = sqlite3_value_text(argv[1]);
int escape = 0;
if( argc==3 ){
/* The escape character string must consist of a single UTF-8 character.
** Otherwise, return an error.
*/
const unsigned char *zEsc = sqlite3_value_text(argv[2]);
if( sqlite3utf8CharLen(zEsc, -1)!=1 ){
sqlite3_result_error(context,
"ESCAPE expression must be a single character", -1);
return;
}
escape = sqlite3ReadUtf8(zEsc);
}
if( zA && zB ){
sqlite3_result_int(context, patternCompare(zA, zB, &likeInfo));
sqlite3_result_int(context, patternCompare(zA, zB, &likeInfo, escape));
}
}
@@ -469,13 +495,13 @@ static void likeFunc(
**
** A GLOB B
**
** is implemented as glob(A,B).
** is implemented as glob(B,A).
*/
static void globFunc(sqlite3_context *context, int arg, sqlite3_value **argv){
const unsigned char *zA = sqlite3_value_text(argv[0]);
const unsigned char *zB = sqlite3_value_text(argv[1]);
if( zA && zB ){
sqlite3_result_int(context, patternCompare(zA, zB, &globInfo));
sqlite3_result_int(context, patternCompare(zA, zB, &globInfo, 0));
}
}
@@ -992,6 +1018,7 @@ void sqlite3RegisterBuiltinFunctions(sqlite3 *db){
{ "ifnull", 2, 0, SQLITE_UTF8, 1, ifnullFunc },
{ "random", -1, 0, SQLITE_UTF8, 0, randomFunc },
{ "like", 2, 0, SQLITE_UTF8, 0, likeFunc },
{ "like", 3, 0, SQLITE_UTF8, 0, likeFunc },
{ "glob", 2, 0, SQLITE_UTF8, 0, globFunc },
{ "nullif", 2, 0, SQLITE_UTF8, 1, nullifFunc },
{ "sqlite_version", 0, 0, SQLITE_UTF8, 0, versionFunc},