mirror of
https://github.com/postgres/postgres.git
synced 2025-11-12 05:01:15 +03:00
Reimplement LIKE/ESCAPE as operators so that indexscan optimization
can still work, per recent discussion on pghackers. Correct some bugs in ILIKE implementation.
This commit is contained in:
@@ -11,12 +11,14 @@
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/utils/adt/like.c,v 1.41 2000/08/22 06:33:57 ishii Exp $
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* $Header: /cvsroot/pgsql/src/backend/utils/adt/like.c,v 1.42 2000/09/15 18:45:26 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include <ctype.h>
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#ifdef MULTIBYTE
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#include "mb/pg_wchar.h"
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#endif
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@@ -28,391 +30,12 @@
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#define LIKE_ABORT (-1)
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static int MatchText(unsigned char * t, int tlen, unsigned char * p, int plen, char *e);
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static int MatchTextLower(unsigned char * t, int tlen, unsigned char * p, int plen, char *e);
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static int MatchText(unsigned char * t, int tlen,
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unsigned char * p, int plen);
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static int MatchTextIC(unsigned char * t, int tlen,
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unsigned char * p, int plen);
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/*
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* interface routines called by the function manager
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*/
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Datum
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namelike(PG_FUNCTION_ARGS)
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{
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bool result;
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Name str = PG_GETARG_NAME(0);
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text *pat = PG_GETARG_TEXT_P(1);
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unsigned char *s, *p;
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int slen, plen;
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s = NameStr(*str);
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slen = strlen(s);
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p = VARDATA(pat);
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plen = (VARSIZE(pat)-VARHDRSZ);
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result = (MatchText(s, slen, p, plen, "\\") == LIKE_TRUE);
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PG_RETURN_BOOL(result);
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}
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Datum
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namenlike(PG_FUNCTION_ARGS)
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{
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bool result;
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Name str = PG_GETARG_NAME(0);
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text *pat = PG_GETARG_TEXT_P(1);
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unsigned char *s, *p;
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int slen, plen;
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s = NameStr(*str);
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slen = strlen(s);
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p = VARDATA(pat);
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plen = (VARSIZE(pat)-VARHDRSZ);
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result = (MatchText(s, slen, p, plen, "\\") != LIKE_TRUE);
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PG_RETURN_BOOL(result);
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}
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Datum
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namelike_escape(PG_FUNCTION_ARGS)
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{
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bool result;
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Name str = PG_GETARG_NAME(0);
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text *pat = PG_GETARG_TEXT_P(1);
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text *esc = PG_GETARG_TEXT_P(2);
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unsigned char *s, *p;
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int slen, plen;
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char *e;
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s = NameStr(*str);
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slen = strlen(s);
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p = VARDATA(pat);
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plen = (VARSIZE(pat)-VARHDRSZ);
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e = ((VARSIZE(esc)-VARHDRSZ) > 0? VARDATA(esc): NULL);
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result = (MatchText(s, slen, p, plen, e) == LIKE_TRUE);
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PG_RETURN_BOOL(result);
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}
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Datum
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namenlike_escape(PG_FUNCTION_ARGS)
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{
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bool result;
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Name str = PG_GETARG_NAME(0);
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text *pat = PG_GETARG_TEXT_P(1);
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text *esc = PG_GETARG_TEXT_P(2);
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unsigned char *s, *p;
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int slen, plen;
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char *e;
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s = NameStr(*str);
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slen = strlen(s);
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p = VARDATA(pat);
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plen = (VARSIZE(pat)-VARHDRSZ);
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e = ((VARSIZE(esc)-VARHDRSZ) > 0? VARDATA(esc): NULL);
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result = (MatchText(s, slen, p, plen, e) != LIKE_TRUE);
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PG_RETURN_BOOL(result);
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}
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Datum
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textlike(PG_FUNCTION_ARGS)
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{
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bool result;
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text *str = PG_GETARG_TEXT_P(0);
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text *pat = PG_GETARG_TEXT_P(1);
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unsigned char *s, *p;
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int slen, plen;
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s = VARDATA(str);
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slen = (VARSIZE(str)-VARHDRSZ);
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p = VARDATA(pat);
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plen = (VARSIZE(pat)-VARHDRSZ);
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result = (MatchText(s, slen, p, plen, NULL) == LIKE_TRUE);
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PG_RETURN_BOOL(result);
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}
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Datum
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textnlike(PG_FUNCTION_ARGS)
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{
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bool result;
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text *str = PG_GETARG_TEXT_P(0);
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text *pat = PG_GETARG_TEXT_P(1);
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unsigned char *s, *p;
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int slen, plen;
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s = VARDATA(str);
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slen = (VARSIZE(str)-VARHDRSZ);
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p = VARDATA(pat);
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plen = (VARSIZE(pat)-VARHDRSZ);
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result = (MatchText(s, slen, p, plen, "\\") != LIKE_TRUE);
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PG_RETURN_BOOL(result);
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}
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Datum
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textlike_escape(PG_FUNCTION_ARGS)
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{
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bool result;
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text *str = PG_GETARG_TEXT_P(0);
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text *pat = PG_GETARG_TEXT_P(1);
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text *esc = PG_GETARG_TEXT_P(2);
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unsigned char *s, *p;
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int slen, plen;
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char *e;
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s = VARDATA(str);
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slen = (VARSIZE(str)-VARHDRSZ);
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p = VARDATA(pat);
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plen = (VARSIZE(pat)-VARHDRSZ);
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e = ((VARSIZE(esc)-VARHDRSZ) > 0? VARDATA(esc): NULL);
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result = (MatchText(s, slen, p, plen, e) == LIKE_TRUE);
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PG_RETURN_BOOL(result);
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}
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Datum
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textnlike_escape(PG_FUNCTION_ARGS)
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{
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bool result;
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text *str = PG_GETARG_TEXT_P(0);
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text *pat = PG_GETARG_TEXT_P(1);
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text *esc = PG_GETARG_TEXT_P(2);
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unsigned char *s, *p;
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int slen, plen;
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char *e;
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s = VARDATA(str);
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slen = (VARSIZE(str)-VARHDRSZ);
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p = VARDATA(pat);
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plen = (VARSIZE(pat)-VARHDRSZ);
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e = ((VARSIZE(esc)-VARHDRSZ) > 0? VARDATA(esc): NULL);
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result = (MatchText(s, slen, p, plen, e) != LIKE_TRUE);
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PG_RETURN_BOOL(result);
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}
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/*
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* Case-insensitive versions
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*/
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Datum
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inamelike(PG_FUNCTION_ARGS)
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{
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bool result;
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Name str = PG_GETARG_NAME(0);
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text *pat = PG_GETARG_TEXT_P(1);
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unsigned char *s, *p;
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int slen, plen;
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s = NameStr(*str);
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slen = strlen(s);
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p = VARDATA(pat);
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plen = (VARSIZE(pat)-VARHDRSZ);
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result = (MatchTextLower(s, slen, p, plen, "\\") == LIKE_TRUE);
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PG_RETURN_BOOL(result);
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}
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Datum
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inamenlike(PG_FUNCTION_ARGS)
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{
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bool result;
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Name str = PG_GETARG_NAME(0);
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text *pat = PG_GETARG_TEXT_P(1);
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unsigned char *s, *p;
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int slen, plen;
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s = NameStr(*str);
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slen = strlen(s);
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p = VARDATA(pat);
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plen = (VARSIZE(pat)-VARHDRSZ);
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result = (MatchTextLower(s, slen, p, plen, "\\") != LIKE_TRUE);
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PG_RETURN_BOOL(result);
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}
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Datum
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inamelike_escape(PG_FUNCTION_ARGS)
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{
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bool result;
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Name str = PG_GETARG_NAME(0);
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text *pat = PG_GETARG_TEXT_P(1);
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text *esc = PG_GETARG_TEXT_P(2);
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unsigned char *s, *p;
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int slen, plen;
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char *e;
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s = NameStr(*str);
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slen = strlen(s);
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p = VARDATA(pat);
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plen = (VARSIZE(pat)-VARHDRSZ);
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e = ((VARSIZE(esc)-VARHDRSZ) > 0? VARDATA(esc): NULL);
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result = (MatchTextLower(s, slen, p, plen, e) == LIKE_TRUE);
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PG_RETURN_BOOL(result);
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}
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Datum
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inamenlike_escape(PG_FUNCTION_ARGS)
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{
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bool result;
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Name str = PG_GETARG_NAME(0);
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text *pat = PG_GETARG_TEXT_P(1);
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text *esc = PG_GETARG_TEXT_P(2);
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unsigned char *s, *p;
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int slen, plen;
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char *e;
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s = NameStr(*str);
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slen = strlen(s);
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p = VARDATA(pat);
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plen = (VARSIZE(pat)-VARHDRSZ);
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e = ((VARSIZE(esc)-VARHDRSZ) > 0? VARDATA(esc): NULL);
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result = (MatchTextLower(s, slen, p, plen, e) != LIKE_TRUE);
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PG_RETURN_BOOL(result);
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}
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Datum
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itextlike(PG_FUNCTION_ARGS)
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{
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bool result;
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text *str = PG_GETARG_TEXT_P(0);
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text *pat = PG_GETARG_TEXT_P(1);
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unsigned char *s, *p;
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int slen, plen;
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s = VARDATA(str);
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slen = (VARSIZE(str)-VARHDRSZ);
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p = VARDATA(pat);
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plen = (VARSIZE(pat)-VARHDRSZ);
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result = (MatchTextLower(s, slen, p, plen, "\\") == LIKE_TRUE);
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PG_RETURN_BOOL(result);
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}
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Datum
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itextnlike(PG_FUNCTION_ARGS)
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{
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bool result;
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text *str = PG_GETARG_TEXT_P(0);
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text *pat = PG_GETARG_TEXT_P(1);
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unsigned char *s, *p;
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int slen, plen;
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s = VARDATA(str);
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slen = (VARSIZE(str)-VARHDRSZ);
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p = VARDATA(pat);
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plen = (VARSIZE(pat)-VARHDRSZ);
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result = (MatchTextLower(s, slen, p, plen, "\\") != LIKE_TRUE);
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PG_RETURN_BOOL(result);
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}
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Datum
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itextlike_escape(PG_FUNCTION_ARGS)
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{
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bool result;
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text *str = PG_GETARG_TEXT_P(0);
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text *pat = PG_GETARG_TEXT_P(1);
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text *esc = PG_GETARG_TEXT_P(2);
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unsigned char *s, *p;
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int slen, plen;
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char *e;
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s = VARDATA(str);
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slen = (VARSIZE(str)-VARHDRSZ);
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p = VARDATA(pat);
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plen = (VARSIZE(pat)-VARHDRSZ);
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e = ((VARSIZE(esc)-VARHDRSZ) > 0? VARDATA(esc): NULL);
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result = (MatchTextLower(s, slen, p, plen, e) == LIKE_TRUE);
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PG_RETURN_BOOL(result);
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}
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Datum
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itextnlike_escape(PG_FUNCTION_ARGS)
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{
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bool result;
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text *str = PG_GETARG_TEXT_P(0);
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text *pat = PG_GETARG_TEXT_P(1);
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text *esc = PG_GETARG_TEXT_P(2);
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unsigned char *s, *p;
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int slen, plen;
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char *e;
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s = VARDATA(str);
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slen = (VARSIZE(str)-VARHDRSZ);
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p = VARDATA(pat);
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plen = (VARSIZE(pat)-VARHDRSZ);
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e = ((VARSIZE(esc)-VARHDRSZ) > 0? VARDATA(esc): NULL);
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result = (MatchTextLower(s, slen, p, plen, e) != LIKE_TRUE);
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PG_RETURN_BOOL(result);
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}
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|
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/*
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** Originally written by Rich $alz, mirror!rs, Wed Nov 26 19:03:17 EST 1986.
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** Rich $alz is now <rsalz@bbn.com>.
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** Special thanks to Lars Mathiesen <thorinn@diku.dk> for the LABORT code.
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**
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** This code was shamelessly stolen from the "pql" code by myself and
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** slightly modified :)
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**
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** All references to the word "star" were replaced by "percent"
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** All references to the word "wild" were replaced by "like"
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**
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** All the nice shell RE matching stuff was replaced by just "_" and "%"
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**
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** As I don't have a copy of the SQL standard handy I wasn't sure whether
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** to leave in the '\' escape character handling.
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**
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** Keith Parks. <keith@mtcc.demon.co.uk>
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**
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** [SQL92 lets you specify the escape character by saying
|
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** LIKE <pattern> ESCAPE <escape character>. We are a small operation
|
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** so we force you to use '\'. - ay 7/95]
|
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**
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** OK, we now support the SQL9x LIKE <pattern> ESCAPE <char> syntax.
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** We should kill the backslash escaping mechanism since it is non-standard
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** and undocumented afaik.
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** The code is rewritten to avoid requiring null-terminated strings,
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** which in turn allows us to leave out some memcpy() operations.
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** This code should be faster and take less memory, but no promises...
|
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** - thomas 2000-08-06
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**
|
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*/
|
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|
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/*--------------------
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* Match text and p, return LIKE_TRUE, LIKE_FALSE, or LIKE_ABORT.
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*
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* LIKE_TRUE: they match
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* LIKE_FALSE: they don't match
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* LIKE_ABORT: not only don't they match, but the text is too short.
|
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*
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* If LIKE_ABORT is returned, then no suffix of the text can match the
|
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* pattern either, so an upper-level % scan can stop scanning now.
|
||||
*--------------------
|
||||
*/
|
||||
|
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#ifdef MULTIBYTE
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/*--------------------
|
||||
* Support routine for MatchText. Compares given multibyte streams
|
||||
@@ -435,7 +58,7 @@ static int wchareq(unsigned char *p1, unsigned char *p2)
|
||||
}
|
||||
|
||||
/*--------------------
|
||||
* Support routine for MatchTextLower. Compares given multibyte streams
|
||||
* Support routine for MatchTextIC. Compares given multibyte streams
|
||||
* as wide characters ignoring case.
|
||||
* If they match, returns 1 otherwise returns 0.
|
||||
*--------------------
|
||||
@@ -470,36 +93,338 @@ static int iwchareq(unsigned char *p1, unsigned char *p2)
|
||||
}
|
||||
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;}
|
||||
#define NextChar(p, plen) \
|
||||
do { int __l = pg_mblen(p); (p) +=__l; (plen) -=__l; } while (0)
|
||||
#define CopyAdvChar(dst, src, srclen) \
|
||||
do { int __l = pg_mblen(src); \
|
||||
(srclen) -= __l; \
|
||||
while (__l-- > 0) \
|
||||
*(dst)++ = *(src)++; \
|
||||
} while (0)
|
||||
#else
|
||||
#define CHAREQ(p1, p2) (*(p1) == *(p2))
|
||||
#define ICHAREQ(p1, p2) (tolower(*(p1)) == tolower(*(p2)))
|
||||
#define NextChar(p, plen) (p)++, (plen)--
|
||||
#define NextChar(p, plen) ((p)++, (plen)--)
|
||||
#define CopyAdvChar(dst, src, srclen) (*(dst)++ = *(src)++, (srclen)--)
|
||||
#endif
|
||||
|
||||
static int
|
||||
MatchText(unsigned char * t, int tlen, unsigned char * p, int plen, char *e)
|
||||
|
||||
/*
|
||||
* interface routines called by the function manager
|
||||
*/
|
||||
|
||||
Datum
|
||||
namelike(PG_FUNCTION_ARGS)
|
||||
{
|
||||
/* 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.
|
||||
Name str = PG_GETARG_NAME(0);
|
||||
text *pat = PG_GETARG_TEXT_P(1);
|
||||
bool result;
|
||||
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)
|
||||
{
|
||||
Name str = PG_GETARG_NAME(0);
|
||||
text *pat = PG_GETARG_TEXT_P(1);
|
||||
bool result;
|
||||
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
|
||||
textlike(PG_FUNCTION_ARGS)
|
||||
{
|
||||
text *str = PG_GETARG_TEXT_P(0);
|
||||
text *pat = PG_GETARG_TEXT_P(1);
|
||||
bool result;
|
||||
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
|
||||
textnlike(PG_FUNCTION_ARGS)
|
||||
{
|
||||
text *str = PG_GETARG_TEXT_P(0);
|
||||
text *pat = PG_GETARG_TEXT_P(1);
|
||||
bool result;
|
||||
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);
|
||||
}
|
||||
|
||||
/*
|
||||
* Case-insensitive versions
|
||||
*/
|
||||
|
||||
Datum
|
||||
nameiclike(PG_FUNCTION_ARGS)
|
||||
{
|
||||
Name str = PG_GETARG_NAME(0);
|
||||
text *pat = PG_GETARG_TEXT_P(1);
|
||||
bool result;
|
||||
unsigned char *s, *p;
|
||||
int slen, plen;
|
||||
|
||||
s = NameStr(*str);
|
||||
slen = strlen(s);
|
||||
p = VARDATA(pat);
|
||||
plen = (VARSIZE(pat)-VARHDRSZ);
|
||||
|
||||
result = (MatchTextIC(s, slen, p, plen) == LIKE_TRUE);
|
||||
|
||||
PG_RETURN_BOOL(result);
|
||||
}
|
||||
|
||||
Datum
|
||||
nameicnlike(PG_FUNCTION_ARGS)
|
||||
{
|
||||
Name str = PG_GETARG_NAME(0);
|
||||
text *pat = PG_GETARG_TEXT_P(1);
|
||||
bool result;
|
||||
unsigned char *s, *p;
|
||||
int slen, plen;
|
||||
|
||||
s = NameStr(*str);
|
||||
slen = strlen(s);
|
||||
p = VARDATA(pat);
|
||||
plen = (VARSIZE(pat)-VARHDRSZ);
|
||||
|
||||
result = (MatchTextIC(s, slen, p, plen) != LIKE_TRUE);
|
||||
|
||||
PG_RETURN_BOOL(result);
|
||||
}
|
||||
|
||||
Datum
|
||||
texticlike(PG_FUNCTION_ARGS)
|
||||
{
|
||||
text *str = PG_GETARG_TEXT_P(0);
|
||||
text *pat = PG_GETARG_TEXT_P(1);
|
||||
bool result;
|
||||
unsigned char *s, *p;
|
||||
int slen, plen;
|
||||
|
||||
s = VARDATA(str);
|
||||
slen = (VARSIZE(str)-VARHDRSZ);
|
||||
p = VARDATA(pat);
|
||||
plen = (VARSIZE(pat)-VARHDRSZ);
|
||||
|
||||
result = (MatchTextIC(s, slen, p, plen) == LIKE_TRUE);
|
||||
|
||||
PG_RETURN_BOOL(result);
|
||||
}
|
||||
|
||||
Datum
|
||||
texticnlike(PG_FUNCTION_ARGS)
|
||||
{
|
||||
text *str = PG_GETARG_TEXT_P(0);
|
||||
text *pat = PG_GETARG_TEXT_P(1);
|
||||
bool result;
|
||||
unsigned char *s, *p;
|
||||
int slen, plen;
|
||||
|
||||
s = VARDATA(str);
|
||||
slen = (VARSIZE(str)-VARHDRSZ);
|
||||
p = VARDATA(pat);
|
||||
plen = (VARSIZE(pat)-VARHDRSZ);
|
||||
|
||||
result = (MatchTextIC(s, slen, p, plen) != LIKE_TRUE);
|
||||
|
||||
PG_RETURN_BOOL(result);
|
||||
}
|
||||
|
||||
/*
|
||||
* like_escape() --- given a pattern and an ESCAPE string,
|
||||
* convert the pattern to use Postgres' standard backslash escape convention.
|
||||
*/
|
||||
Datum
|
||||
like_escape(PG_FUNCTION_ARGS)
|
||||
{
|
||||
text *pat = PG_GETARG_TEXT_P(0);
|
||||
text *esc = PG_GETARG_TEXT_P(1);
|
||||
text *result;
|
||||
unsigned char *p, *e, *r;
|
||||
int plen, elen;
|
||||
bool afterescape;
|
||||
|
||||
p = VARDATA(pat);
|
||||
plen = (VARSIZE(pat)-VARHDRSZ);
|
||||
e = VARDATA(esc);
|
||||
elen = (VARSIZE(esc)-VARHDRSZ);
|
||||
|
||||
/*
|
||||
* Worst-case pattern growth is 2x --- unlikely, but it's hardly worth
|
||||
* trying to calculate the size more accurately than that.
|
||||
*/
|
||||
if ((plen == 1) && (*p == '%')
|
||||
&& ! ((e != NULL) && (*e == '%')))
|
||||
result = (text *) palloc(plen * 2 + VARHDRSZ);
|
||||
r = VARDATA(result);
|
||||
|
||||
if (elen == 0)
|
||||
{
|
||||
/*
|
||||
* No escape character is wanted. Double any backslashes in the
|
||||
* pattern to make them act like ordinary characters.
|
||||
*/
|
||||
while (plen > 0)
|
||||
{
|
||||
if (*p == '\\')
|
||||
*r++ = '\\';
|
||||
CopyAdvChar(r, p, plen);
|
||||
}
|
||||
}
|
||||
else
|
||||
{
|
||||
/*
|
||||
* The specified escape must be only a single character.
|
||||
*/
|
||||
NextChar(e, elen);
|
||||
if (elen != 0)
|
||||
elog(ERROR, "ESCAPE string must be empty or one character");
|
||||
e = VARDATA(esc);
|
||||
/*
|
||||
* If specified escape is '\', just copy the pattern as-is.
|
||||
*/
|
||||
if (*e == '\\')
|
||||
{
|
||||
memcpy(result, pat, VARSIZE(pat));
|
||||
PG_RETURN_TEXT_P(result);
|
||||
}
|
||||
/*
|
||||
* Otherwise, convert occurrences of the specified escape character
|
||||
* to '\', and double occurrences of '\' --- unless they immediately
|
||||
* follow an escape character!
|
||||
*/
|
||||
afterescape = false;
|
||||
while (plen > 0)
|
||||
{
|
||||
if (CHAREQ(p,e) && !afterescape)
|
||||
{
|
||||
*r++ = '\\';
|
||||
NextChar(p, plen);
|
||||
afterescape = true;
|
||||
}
|
||||
else if (*p == '\\')
|
||||
{
|
||||
*r++ = '\\';
|
||||
if (! afterescape)
|
||||
*r++ = '\\';
|
||||
NextChar(p, plen);
|
||||
afterescape = false;
|
||||
}
|
||||
else
|
||||
{
|
||||
CopyAdvChar(r, p, plen);
|
||||
afterescape = false;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
VARATT_SIZEP(result) = r - ((unsigned char *) result);
|
||||
|
||||
PG_RETURN_TEXT_P(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
|
||||
**
|
||||
** Now we have the like_escape() function that converts patterns with
|
||||
** any specified escape character (or none at all) to the internal
|
||||
** default escape character, which is still '\'. - tgl 9/2000
|
||||
**
|
||||
** 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.
|
||||
*--------------------
|
||||
*/
|
||||
|
||||
static int
|
||||
MatchText(unsigned char * t, int tlen, unsigned char * p, int plen)
|
||||
{
|
||||
/* Fast path for match-everything pattern */
|
||||
if ((plen == 1) && (*p == '%'))
|
||||
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))
|
||||
if (*p == '\\')
|
||||
{
|
||||
/* Next pattern char must match literally, whatever it is */
|
||||
NextChar(p, plen);
|
||||
if ((plen <= 0) || !CHAREQ(t,p))
|
||||
return LIKE_FALSE;
|
||||
@@ -525,10 +450,9 @@ MatchText(unsigned char * t, int tlen, unsigned char * p, int plen, char *e)
|
||||
* recurse unless first pattern char might match this
|
||||
* text char.
|
||||
*/
|
||||
if (CHAREQ(t,p) || (*p == '_')
|
||||
|| ((e != NULL) && CHAREQ(p,e)))
|
||||
if (CHAREQ(t,p) || (*p == '\\') || (*p == '_'))
|
||||
{
|
||||
int matched = MatchText(t, tlen, p, plen, e);
|
||||
int matched = MatchText(t, tlen, p, plen);
|
||||
|
||||
if (matched != LIKE_FALSE)
|
||||
return matched; /* TRUE or ABORT */
|
||||
@@ -571,24 +495,21 @@ MatchText(unsigned char * t, int tlen, unsigned char * p, int plen, char *e)
|
||||
return LIKE_ABORT;
|
||||
} /* MatchText() */
|
||||
|
||||
/*
|
||||
* Same as above, but ignore case
|
||||
*/
|
||||
static int
|
||||
MatchTextLower(unsigned char * t, int tlen, unsigned char * p, int plen, char *e)
|
||||
MatchTextIC(unsigned char * t, int tlen, unsigned char * p, int plen)
|
||||
{
|
||||
/* 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 == '%')))
|
||||
/* Fast path for match-everything pattern */
|
||||
if ((plen == 1) && (*p == '%'))
|
||||
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))
|
||||
if (*p == '\\')
|
||||
{
|
||||
/* Next pattern char must match literally, whatever it is */
|
||||
NextChar(p, plen);
|
||||
if ((plen <= 0) || !ICHAREQ(t,p))
|
||||
return LIKE_FALSE;
|
||||
@@ -614,10 +535,9 @@ MatchTextLower(unsigned char * t, int tlen, unsigned char * p, int plen, char *e
|
||||
* recurse unless first pattern char might match this
|
||||
* text char.
|
||||
*/
|
||||
if (ICHAREQ(t,p) || (*p == '_')
|
||||
|| ((e != NULL) && ICHAREQ(p,e)))
|
||||
if (ICHAREQ(t,p) || (*p == '\\') || (*p == '_'))
|
||||
{
|
||||
int matched = MatchText(t, tlen, p, plen, e);
|
||||
int matched = MatchTextIC(t, tlen, p, plen);
|
||||
|
||||
if (matched != LIKE_FALSE)
|
||||
return matched; /* TRUE or ABORT */
|
||||
@@ -634,6 +554,9 @@ MatchTextLower(unsigned char * t, int tlen, unsigned char * p, int plen, char *e
|
||||
}
|
||||
else if ((*p != '_') && !ICHAREQ(t,p))
|
||||
{
|
||||
/* Not the single-character wildcard and no explicit match?
|
||||
* Then time to quit...
|
||||
*/
|
||||
return LIKE_FALSE;
|
||||
}
|
||||
|
||||
@@ -655,4 +578,4 @@ MatchTextLower(unsigned char * t, int tlen, unsigned char * p, int plen, char *e
|
||||
* start matching this pattern.
|
||||
*/
|
||||
return LIKE_ABORT;
|
||||
} /* MatchTextLower() */
|
||||
} /* MatchTextIC() */
|
||||
|
||||
Reference in New Issue
Block a user