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* Copyright (c) 1996-2009, PostgreSQL Global Development Group
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* $PostgreSQL: pgsql/src/backend/utils/adt/like_match.c,v 1.24 2009/01/01 17:23:49 momjian Exp $
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* $PostgreSQL: pgsql/src/backend/utils/adt/like_match.c,v 1.26 2009/06/11 14:49:03 momjian Exp $
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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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** This code was shamelessly stolen from the "pql" code by myself and
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** slightly modified :)
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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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** All the nice shell RE matching stuff was replaced by just "_" and "%"
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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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** Keith Parks. <keith@mtcc.demon.co.uk>
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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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** Now we have the like_escape() function that converts patterns with
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** any specified escape character (or none at all) to the internal
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** default escape character, which is still '\'. - tgl 9/2000
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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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* 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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* This code was shamelessly stolen from the "pql" code by myself and
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* slightly modified :)
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* All references to the word "star" were replaced by "percent"
36
* All references to the word "wild" were replaced by "like"
38
* All the nice shell RE matching stuff was replaced by just "_" and "%"
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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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* Keith Parks. <keith@mtcc.demon.co.uk>
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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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* Now we have the like_escape() function that converts patterns with
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* any specified escape character (or none at all) to the internal
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* default escape character, which is still '\'. - tgl 9/2000
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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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/*--------------------
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* Match text and p, return LIKE_TRUE, LIKE_FALSE, or LIKE_ABORT.
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* Match text and pattern, return LIKE_TRUE, LIKE_FALSE, or LIKE_ABORT.
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* LIKE_TRUE: they match
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* LIKE_FALSE: they don't match
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MatchText(char *t, int tlen, char *p, int plen)
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/* Fast path for match-everything pattern */
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if ((plen == 1) && (*p == '%'))
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if (plen == 1 && *p == '%')
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* In this loop, we advance by char when matching wildcards (and thus on
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* recursive entry to this function we are properly char-synced). On other
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* occasions it is safe to advance by byte, as the text and pattern will
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* be in lockstep. This allows us to perform all comparisons between the
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* be in lockstep. This allows us to perform all comparisons between the
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* text and pattern on a byte by byte basis, even for multi-byte
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while ((tlen > 0) && (plen > 0))
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while (tlen > 0 && plen > 0)
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* rest of the pattern.
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/* %_ is the same as _% - avoid matching _ repeatedly */
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return (plen <= 0) ? LIKE_TRUE : LIKE_ABORT;
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} while (tlen > 0 && plen > 0 && *p == '_');
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* If we are at the end of the pattern, succeed: % followed by
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* n _'s matches any string of at least n characters, and we
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* have now found there are at least n characters.
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/* Look for a place that matches the rest of the pattern */
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int matched = MatchText(t, tlen, p, plen);
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else if (*p == '_')
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/* _ matches any single character, and we know there is one */
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NextChar(t, tlen);
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NextByte(p, plen);
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else if (TCHAR(*t) != TCHAR(*p))
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else if (TCHAR (*p) != TCHAR (*t))
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* Not the single-character wildcard and no explicit match? Then
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/* non-wildcard pattern char fails to match text char */
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return LIKE_FALSE;
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* Pattern and text match, so advance.
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* It is safe to use NextByte instead of NextChar here, even for
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* multi-byte character sets, because we are not following immediately
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* after a wildcard character. If we are in the middle of a multibyte
added
removed
src/backend/utils/adt/like_match.c
