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postgresql/src/backend/utils/adt/like.c

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/*-------------------------------------------------------------------------
*
* like.c
* like expression handling code.
*
* NOTES
* A big hack of the regexp.c code!! Contributed by
* Keith Parks <emkxp01@mtcc.demon.co.uk> (7/95).
*
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/adt/like.c,v 1.41 2000/08/22 06:33:57 ishii Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <ctype.h>
#ifdef MULTIBYTE
#include "mb/pg_wchar.h"
#endif
#include "utils/builtins.h"
#define LIKE_TRUE 1
#define LIKE_FALSE 0
#define LIKE_ABORT (-1)
static int MatchText(unsigned char * t, int tlen, unsigned char * p, int plen, char *e);
static int MatchTextLower(unsigned char * t, int tlen, unsigned char * p, int plen, char *e);
/*
* interface routines called by the function manager
*/
Datum
namelike(PG_FUNCTION_ARGS)
{
bool result;
Name str = PG_GETARG_NAME(0);
text *pat = PG_GETARG_TEXT_P(1);
unsigned char *s, *p;
int slen, plen;
s = NameStr(*str);
slen = strlen(s);
p = VARDATA(pat);
plen = (VARSIZE(pat)-VARHDRSZ);
result = (MatchText(s, slen, p, plen, "\\") == LIKE_TRUE);
PG_RETURN_BOOL(result);
}
Datum
namenlike(PG_FUNCTION_ARGS)
{
bool result;
Name str = PG_GETARG_NAME(0);
text *pat = PG_GETARG_TEXT_P(1);
unsigned char *s, *p;
int slen, plen;
s = NameStr(*str);
slen = strlen(s);
p = VARDATA(pat);
plen = (VARSIZE(pat)-VARHDRSZ);
result = (MatchText(s, slen, p, plen, "\\") != LIKE_TRUE);
PG_RETURN_BOOL(result);
}
Datum
namelike_escape(PG_FUNCTION_ARGS)
{
bool result;
Name str = PG_GETARG_NAME(0);
text *pat = PG_GETARG_TEXT_P(1);
text *esc = PG_GETARG_TEXT_P(2);
unsigned char *s, *p;
int slen, plen;
char *e;
s = NameStr(*str);
slen = strlen(s);
p = VARDATA(pat);
plen = (VARSIZE(pat)-VARHDRSZ);
e = ((VARSIZE(esc)-VARHDRSZ) > 0? VARDATA(esc): NULL);
result = (MatchText(s, slen, p, plen, e) == LIKE_TRUE);
PG_RETURN_BOOL(result);
}
Datum
namenlike_escape(PG_FUNCTION_ARGS)
{
bool result;
Name str = PG_GETARG_NAME(0);
text *pat = PG_GETARG_TEXT_P(1);
text *esc = PG_GETARG_TEXT_P(2);
unsigned char *s, *p;
int slen, plen;
char *e;
s = NameStr(*str);
slen = strlen(s);
p = VARDATA(pat);
plen = (VARSIZE(pat)-VARHDRSZ);
e = ((VARSIZE(esc)-VARHDRSZ) > 0? VARDATA(esc): NULL);
result = (MatchText(s, slen, p, plen, e) != LIKE_TRUE);
PG_RETURN_BOOL(result);
}
Datum
textlike(PG_FUNCTION_ARGS)
{
bool result;
text *str = PG_GETARG_TEXT_P(0);
text *pat = PG_GETARG_TEXT_P(1);
unsigned char *s, *p;
int slen, plen;
s = VARDATA(str);
slen = (VARSIZE(str)-VARHDRSZ);
p = VARDATA(pat);
plen = (VARSIZE(pat)-VARHDRSZ);
result = (MatchText(s, slen, p, plen, NULL) == LIKE_TRUE);
PG_RETURN_BOOL(result);
}
Datum
textnlike(PG_FUNCTION_ARGS)
{
bool result;
text *str = PG_GETARG_TEXT_P(0);
text *pat = PG_GETARG_TEXT_P(1);
unsigned char *s, *p;
int slen, plen;
s = VARDATA(str);
slen = (VARSIZE(str)-VARHDRSZ);
p = VARDATA(pat);
plen = (VARSIZE(pat)-VARHDRSZ);
result = (MatchText(s, slen, p, plen, "\\") != LIKE_TRUE);
PG_RETURN_BOOL(result);
}
Datum
textlike_escape(PG_FUNCTION_ARGS)
{
bool result;
text *str = PG_GETARG_TEXT_P(0);
text *pat = PG_GETARG_TEXT_P(1);
text *esc = PG_GETARG_TEXT_P(2);
unsigned char *s, *p;
int slen, plen;
char *e;
s = VARDATA(str);
slen = (VARSIZE(str)-VARHDRSZ);
p = VARDATA(pat);
plen = (VARSIZE(pat)-VARHDRSZ);
e = ((VARSIZE(esc)-VARHDRSZ) > 0? VARDATA(esc): NULL);
result = (MatchText(s, slen, p, plen, e) == LIKE_TRUE);
PG_RETURN_BOOL(result);
}
Datum
textnlike_escape(PG_FUNCTION_ARGS)
{
bool result;
text *str = PG_GETARG_TEXT_P(0);
text *pat = PG_GETARG_TEXT_P(1);
text *esc = PG_GETARG_TEXT_P(2);
unsigned char *s, *p;
int slen, plen;
char *e;
s = VARDATA(str);
slen = (VARSIZE(str)-VARHDRSZ);
p = VARDATA(pat);
plen = (VARSIZE(pat)-VARHDRSZ);
e = ((VARSIZE(esc)-VARHDRSZ) > 0? VARDATA(esc): NULL);
result = (MatchText(s, slen, p, plen, e) != LIKE_TRUE);
PG_RETURN_BOOL(result);
}
/*
* Case-insensitive versions
*/
Datum
inamelike(PG_FUNCTION_ARGS)
{
bool result;
Name str = PG_GETARG_NAME(0);
text *pat = PG_GETARG_TEXT_P(1);
unsigned char *s, *p;
int slen, plen;
s = NameStr(*str);
slen = strlen(s);
p = VARDATA(pat);
plen = (VARSIZE(pat)-VARHDRSZ);
result = (MatchTextLower(s, slen, p, plen, "\\") == LIKE_TRUE);
PG_RETURN_BOOL(result);
}
Datum
inamenlike(PG_FUNCTION_ARGS)
{
bool result;
Name str = PG_GETARG_NAME(0);
text *pat = PG_GETARG_TEXT_P(1);
unsigned char *s, *p;
int slen, plen;
s = NameStr(*str);
slen = strlen(s);
p = VARDATA(pat);
plen = (VARSIZE(pat)-VARHDRSZ);
result = (MatchTextLower(s, slen, p, plen, "\\") != LIKE_TRUE);
PG_RETURN_BOOL(result);
}
Datum
inamelike_escape(PG_FUNCTION_ARGS)
{
bool result;
Name str = PG_GETARG_NAME(0);
text *pat = PG_GETARG_TEXT_P(1);
text *esc = PG_GETARG_TEXT_P(2);
unsigned char *s, *p;
int slen, plen;
char *e;
s = NameStr(*str);
slen = strlen(s);
p = VARDATA(pat);
plen = (VARSIZE(pat)-VARHDRSZ);
e = ((VARSIZE(esc)-VARHDRSZ) > 0? VARDATA(esc): NULL);
result = (MatchTextLower(s, slen, p, plen, e) == LIKE_TRUE);
PG_RETURN_BOOL(result);
}
Datum
inamenlike_escape(PG_FUNCTION_ARGS)
{
bool result;
Name str = PG_GETARG_NAME(0);
text *pat = PG_GETARG_TEXT_P(1);
text *esc = PG_GETARG_TEXT_P(2);
unsigned char *s, *p;
int slen, plen;
char *e;
s = NameStr(*str);
slen = strlen(s);
p = VARDATA(pat);
plen = (VARSIZE(pat)-VARHDRSZ);
e = ((VARSIZE(esc)-VARHDRSZ) > 0? VARDATA(esc): NULL);
result = (MatchTextLower(s, slen, p, plen, e) != LIKE_TRUE);
PG_RETURN_BOOL(result);
}
Datum
itextlike(PG_FUNCTION_ARGS)
{
bool result;
text *str = PG_GETARG_TEXT_P(0);
text *pat = PG_GETARG_TEXT_P(1);
unsigned char *s, *p;
int slen, plen;
s = VARDATA(str);
slen = (VARSIZE(str)-VARHDRSZ);
p = VARDATA(pat);
plen = (VARSIZE(pat)-VARHDRSZ);
result = (MatchTextLower(s, slen, p, plen, "\\") == LIKE_TRUE);
PG_RETURN_BOOL(result);
}
Datum
itextnlike(PG_FUNCTION_ARGS)
{
bool result;
text *str = PG_GETARG_TEXT_P(0);
text *pat = PG_GETARG_TEXT_P(1);
unsigned char *s, *p;
int slen, plen;
s = VARDATA(str);
slen = (VARSIZE(str)-VARHDRSZ);
p = VARDATA(pat);
plen = (VARSIZE(pat)-VARHDRSZ);
result = (MatchTextLower(s, slen, p, plen, "\\") != LIKE_TRUE);
PG_RETURN_BOOL(result);
}
Datum
itextlike_escape(PG_FUNCTION_ARGS)
{
bool result;
text *str = PG_GETARG_TEXT_P(0);
text *pat = PG_GETARG_TEXT_P(1);
text *esc = PG_GETARG_TEXT_P(2);
unsigned char *s, *p;
int slen, plen;
char *e;
s = VARDATA(str);
slen = (VARSIZE(str)-VARHDRSZ);
p = VARDATA(pat);
plen = (VARSIZE(pat)-VARHDRSZ);
e = ((VARSIZE(esc)-VARHDRSZ) > 0? VARDATA(esc): NULL);
result = (MatchTextLower(s, slen, p, plen, e) == LIKE_TRUE);
PG_RETURN_BOOL(result);
}
Datum
itextnlike_escape(PG_FUNCTION_ARGS)
{
bool result;
text *str = PG_GETARG_TEXT_P(0);
text *pat = PG_GETARG_TEXT_P(1);
text *esc = PG_GETARG_TEXT_P(2);
unsigned char *s, *p;
int slen, plen;
char *e;
s = VARDATA(str);
slen = (VARSIZE(str)-VARHDRSZ);
p = VARDATA(pat);
plen = (VARSIZE(pat)-VARHDRSZ);
e = ((VARSIZE(esc)-VARHDRSZ) > 0? VARDATA(esc): NULL);
result = (MatchTextLower(s, slen, p, plen, e) != LIKE_TRUE);
PG_RETURN_BOOL(result);
}
/*
** Originally written by Rich $alz, mirror!rs, Wed Nov 26 19:03:17 EST 1986.
** Rich $alz is now <rsalz@bbn.com>.
** Special thanks to Lars Mathiesen <thorinn@diku.dk> for the LABORT code.
**
** This code was shamelessly stolen from the "pql" code by myself and
** slightly modified :)
**
** All references to the word "star" were replaced by "percent"
** All references to the word "wild" were replaced by "like"
**
** All the nice shell RE matching stuff was replaced by just "_" and "%"
**
** As I don't have a copy of the SQL standard handy I wasn't sure whether
** to leave in the '\' escape character handling.
**
** Keith Parks. <keith@mtcc.demon.co.uk>
**
** [SQL92 lets you specify the escape character by saying
** LIKE <pattern> ESCAPE <escape character>. We are a small operation
** so we force you to use '\'. - ay 7/95]
**
** OK, we now support the SQL9x LIKE <pattern> ESCAPE <char> syntax.
** We should kill the backslash escaping mechanism since it is non-standard
** and undocumented afaik.
** The code is rewritten to avoid requiring null-terminated strings,
** which in turn allows us to leave out some memcpy() operations.
** This code should be faster and take less memory, but no promises...
** - thomas 2000-08-06
**
*/
/*--------------------
* Match text and p, return LIKE_TRUE, LIKE_FALSE, or LIKE_ABORT.
*
* LIKE_TRUE: they match
* LIKE_FALSE: they don't match
* LIKE_ABORT: not only don't they match, but the text is too short.
*
* If LIKE_ABORT is returned, then no suffix of the text can match the
* pattern either, so an upper-level % scan can stop scanning now.
*--------------------
*/
#ifdef MULTIBYTE
/*--------------------
* Support routine for MatchText. Compares given multibyte streams
* as wide characters. If they match, returns 1 otherwise returns 0.
*--------------------
*/
static int wchareq(unsigned char *p1, unsigned char *p2)
{
int l;
l = pg_mblen(p1);
if (pg_mblen(p2) != l) {
return(0);
}
while (l--) {
if (*p1++ != *p2++)
return(0);
}
return(1);
}
/*--------------------
* Support routine for MatchTextLower. Compares given multibyte streams
* as wide characters ignoring case.
* If they match, returns 1 otherwise returns 0.
*--------------------
*/
#define UCHARMAX 0xff
static int iwchareq(unsigned char *p1, unsigned char *p2)
{
int c1, c2;
int l;
/* short cut. if *p1 and *p2 is lower than UCHARMAX, then
we assume they are ASCII */
if (*p1 < UCHARMAX && *p2 < UCHARMAX)
return(tolower(*p1) == tolower(*p2));
if (*p1 < UCHARMAX)
c1 = tolower(*p1);
else
{
l = pg_mblen(p1);
(void)pg_mb2wchar_with_len(p1, (pg_wchar *)&c1, l);
c1 = tolower(c1);
}
if (*p2 < UCHARMAX)
c2 = tolower(*p2);
else
{
l = pg_mblen(p2);
(void)pg_mb2wchar_with_len(p2, (pg_wchar *)&c2, l);
c2 = tolower(c2);
}
return(c1 == c2);
}
#endif
#ifdef MULTIBYTE
#define CHAREQ(p1, p2) wchareq(p1, p2)
#define ICHAREQ(p1, p2) iwchareq(p1, p2)
#define NextChar(p, plen) {int __l = pg_mblen(p); (p) +=__l; (plen) -=__l;}
#else
#define CHAREQ(p1, p2) (*(p1) == *(p2))
#define ICHAREQ(p1, p2) (tolower(*(p1)) == tolower(*(p2)))
#define NextChar(p, plen) (p)++, (plen)--
#endif
static int
MatchText(unsigned char * t, int tlen, unsigned char * p, int plen, char *e)
{
/* Fast path for match-everything pattern
* Include weird case of escape character as a percent sign or underscore,
* when presumably that wildcard character becomes a literal.
*/
if ((plen == 1) && (*p == '%')
&& ! ((e != NULL) && (*e == '%')))
return LIKE_TRUE;
while ((tlen > 0) && (plen > 0))
{
/* If an escape character was specified and we find it here in the pattern,
* then we'd better have an exact match for the next character.
*/
if ((e != NULL) && CHAREQ(p,e))
{
NextChar(p, plen);
if ((plen <= 0) || !CHAREQ(t,p))
return LIKE_FALSE;
}
else if (*p == '%')
{
/* %% is the same as % according to the SQL standard */
/* Advance past all %'s */
while ((plen > 0) && (*p == '%'))
NextChar(p, plen);
/* Trailing percent matches everything. */
if (plen <= 0)
return LIKE_TRUE;
/*
* Otherwise, scan for a text position at which we can
* match the rest of the pattern.
*/
while (tlen > 0)
{
/*
* Optimization to prevent most recursion: don't
* recurse unless first pattern char might match this
* text char.
*/
if (CHAREQ(t,p) || (*p == '_')
|| ((e != NULL) && CHAREQ(p,e)))
{
int matched = MatchText(t, tlen, p, plen, e);
if (matched != LIKE_FALSE)
return matched; /* TRUE or ABORT */
}
NextChar(t, tlen);
}
/*
* End of text with no match, so no point in trying later
* places to start matching this pattern.
*/
return LIKE_ABORT;
}
else if ((*p != '_') && !CHAREQ(t,p))
{
/* Not the single-character wildcard and no explicit match?
* Then time to quit...
*/
return LIKE_FALSE;
}
NextChar(t, tlen);
NextChar(p, plen);
}
if (tlen > 0)
return LIKE_FALSE; /* end of pattern, but not of text */
/* End of input string. Do we have matching pattern remaining? */
while ((plen > 0) && (*p == '%')) /* allow multiple %'s at end of pattern */
NextChar(p, plen);
if (plen <= 0)
return LIKE_TRUE;
/*
* End of text with no match, so no point in trying later places to
* start matching this pattern.
*/
return LIKE_ABORT;
} /* MatchText() */
static int
MatchTextLower(unsigned char * t, int tlen, unsigned char * p, int plen, char *e)
{
/* Fast path for match-everything pattern
* Include weird case of escape character as a percent sign or underscore,
* when presumably that wildcard character becomes a literal.
*/
if ((plen == 1) && (*p == '%')
&& ! ((e != NULL) && (*e == '%')))
return LIKE_TRUE;
while ((tlen > 0) && (plen > 0))
{
/* If an escape character was specified and we find it here in the pattern,
* then we'd better have an exact match for the next character.
*/
if ((e != NULL) && ICHAREQ(p,e))
{
NextChar(p, plen);
if ((plen <= 0) || !ICHAREQ(t,p))
return LIKE_FALSE;
}
else if (*p == '%')
{
/* %% is the same as % according to the SQL standard */
/* Advance past all %'s */
while ((plen > 0) && (*p == '%'))
NextChar(p, plen);
/* Trailing percent matches everything. */
if (plen <= 0)
return LIKE_TRUE;
/*
* Otherwise, scan for a text position at which we can
* match the rest of the pattern.
*/
while (tlen > 0)
{
/*
* Optimization to prevent most recursion: don't
* recurse unless first pattern char might match this
* text char.
*/
if (ICHAREQ(t,p) || (*p == '_')
|| ((e != NULL) && ICHAREQ(p,e)))
{
int matched = MatchText(t, tlen, p, plen, e);
if (matched != LIKE_FALSE)
return matched; /* TRUE or ABORT */
}
NextChar(t, tlen);
}
/*
* End of text with no match, so no point in trying later
* places to start matching this pattern.
*/
return LIKE_ABORT;
}
else if ((*p != '_') && !ICHAREQ(t,p))
{
return LIKE_FALSE;
}
NextChar(t, tlen);
NextChar(p, plen);
}
if (tlen > 0)
return LIKE_FALSE; /* end of pattern, but not of text */
/* End of input string. Do we have matching pattern remaining? */
while ((plen > 0) && (*p == '%')) /* allow multiple %'s at end of pattern */
NextChar(p, plen);
if (plen <= 0)
return LIKE_TRUE;
/*
* End of text with no match, so no point in trying later places to
* start matching this pattern.
*/
return LIKE_ABORT;
} /* MatchTextLower() */
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