From 15f8202c204386b7a3b95b00976b4c1e7ba062c1 Mon Sep 17 00:00:00 2001
From: Andrew Dunstan <andrew@dunslane.net>
Date: Sat, 2 Jun 2007 02:03:42 +0000
Subject: [PATCH] Improve efficiency of LIKE/ILIKE code, especially for
multi-byte charsets, and most especially for UTF8. Remove unnecessary special
cases for bytea processing and single-byte charset ILIKE. a ILIKE b is now
processed as lower(a) LIKE lower(b) in all cases. The code is now
considerably simpler. All comparisons are now performed byte-wise, and the
text and pattern are also advanced byte-wise where it is safe to do so -
essentially where a wildcard is not being matched. Andrew Dunstan, from an
original patch by ITAGAKI Takahiro, with ideas from Tom Lane and Mark Mielke.
---
src/backend/utils/adt/like.c | 402 ++++++-----------------------
src/backend/utils/adt/like_match.c | 220 ++++++++--------
2 files changed, 183 insertions(+), 439 deletions(-)
diff --git a/src/backend/utils/adt/like.c b/src/backend/utils/adt/like.c
index 46f223b38ff..de5d7e7c859 100644
--- a/src/backend/utils/adt/like.c
+++ b/src/backend/utils/adt/like.c
@@ -11,7 +11,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/adt/like.c,v 1.68 2007/02/27 23:48:08 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/like.c,v 1.69 2007/06/02 02:03:42 adunstan Exp $
*
*-------------------------------------------------------------------------
*/
@@ -28,21 +28,23 @@
#define LIKE_ABORT (-1)
-static int MatchText(char *t, int tlen, char *p, int plen);
-static int MatchTextIC(char *t, int tlen, char *p, int plen);
-static int MatchBytea(char *t, int tlen, char *p, int plen);
-static text *do_like_escape(text *, text *);
+static int SB_MatchText(char *t, int tlen, char *p, int plen);
+static text *SB_do_like_escape(text *, text *);
-static int MBMatchText(char *t, int tlen, char *p, int plen);
-static int MBMatchTextIC(char *t, int tlen, char *p, int plen);
+static int MB_MatchText(char *t, int tlen, char *p, int plen);
static text *MB_do_like_escape(text *, text *);
+static int UTF8_MatchText(char *t, int tlen, char *p, int plen);
+
+static int GenericMatchText(char *s, int slen, char* p, int plen);
+static int Generic_Text_IC_like(text *str, text *pat);
+
/*--------------------
* Support routine for MatchText. Compares given multibyte streams
* as wide characters. If they match, returns 1 otherwise returns 0.
*--------------------
*/
-static int
+static inline int
wchareq(char *p1, char *p2)
{
int p1_len;
@@ -72,15 +74,12 @@ wchareq(char *p1, char *p2)
* of getting a single character transformed to the system's wchar_t format.
* So now, we just downcase the strings using lower() and apply regular LIKE
* comparison. This should be revisited when we install better locale support.
- *
- * Note that MBMatchText and MBMatchTextIC do exactly the same thing now.
- * Is it worth refactoring to avoid duplicated code? They might become
- * different again in the future.
*/
+#define NextByte(p, plen) ((p)++, (plen)--)
+
/* Set up to compile like_match.c for multibyte characters */
-#define CHAREQ(p1, p2) wchareq(p1, p2)
-#define ICHAREQ(p1, p2) wchareq(p1, p2)
+#define CHAREQ(p1, p2) wchareq((p1), (p2))
#define NextChar(p, plen) \
do { int __l = pg_mblen(p); (p) +=__l; (plen) -=__l; } while (0)
#define CopyAdvChar(dst, src, srclen) \
@@ -90,33 +89,59 @@ wchareq(char *p1, char *p2)
*(dst)++ = *(src)++; \
} while (0)
-#define MatchText MBMatchText
-#define MatchTextIC MBMatchTextIC
+#define MatchText MB_MatchText
#define do_like_escape MB_do_like_escape
#include "like_match.c"
-#undef CHAREQ
-#undef ICHAREQ
-#undef NextChar
-#undef CopyAdvChar
-#undef MatchText
-#undef MatchTextIC
-#undef do_like_escape
-
/* Set up to compile like_match.c for single-byte characters */
#define CHAREQ(p1, p2) (*(p1) == *(p2))
-#define ICHAREQ(p1, p2) (tolower((unsigned char) *(p1)) == tolower((unsigned char) *(p2)))
-#define NextChar(p, plen) ((p)++, (plen)--)
+#define NextChar(p, plen) NextByte((p), (plen))
#define CopyAdvChar(dst, src, srclen) (*(dst)++ = *(src)++, (srclen)--)
+#define MatchText SB_MatchText
+#define do_like_escape SB_do_like_escape
+
+#include "like_match.c"
+
+
+/* setup to compile like_match.c for UTF8 encoding, using fast NextChar */
+
+#define NextChar(p, plen) \
+ do { (p)++; (plen)--; } while ((plen) > 0 && (*(p) & 0xC0) == 0x80 )
+#define MatchText UTF8_MatchText
+
#include "like_match.c"
-/* And some support for BYTEA */
-#define BYTEA_CHAREQ(p1, p2) (*(p1) == *(p2))
-#define BYTEA_NextChar(p, plen) ((p)++, (plen)--)
-#define BYTEA_CopyAdvChar(dst, src, srclen) (*(dst)++ = *(src)++, (srclen)--)
+static inline int
+GenericMatchText(char *s, int slen, char* p, int plen)
+{
+ if (pg_database_encoding_max_length() == 1)
+ return SB_MatchText(s, slen, p, plen);
+ else if (GetDatabaseEncoding() == PG_UTF8)
+ return UTF8_MatchText(s, slen, p, plen);
+ else
+ return MB_MatchText(s, slen, p, plen);
+}
+
+static inline int
+Generic_Text_IC_like(text *str, text *pat)
+{
+ char *s,
+ *p;
+ int slen,
+ plen;
+
+ /* Force inputs to lower case to achieve case insensitivity */
+ str = DatumGetTextP(DirectFunctionCall1(lower, PointerGetDatum(str)));
+ pat = DatumGetTextP(DirectFunctionCall1(lower, PointerGetDatum(pat)));
+ s = VARDATA(str);
+ slen = (VARSIZE(str) - VARHDRSZ);
+ p = VARDATA(pat);
+ plen = (VARSIZE(pat) - VARHDRSZ);
+ return GenericMatchText(s, slen, p, plen);
+}
/*
* interface routines called by the function manager
@@ -138,10 +163,7 @@ namelike(PG_FUNCTION_ARGS)
p = VARDATA(pat);
plen = (VARSIZE(pat) - VARHDRSZ);
- if (pg_database_encoding_max_length() == 1)
- result = (MatchText(s, slen, p, plen) == LIKE_TRUE);
- else
- result = (MBMatchText(s, slen, p, plen) == LIKE_TRUE);
+ result = (GenericMatchText(s, slen, p, plen) == LIKE_TRUE);
PG_RETURN_BOOL(result);
}
@@ -162,10 +184,7 @@ namenlike(PG_FUNCTION_ARGS)
p = VARDATA(pat);
plen = (VARSIZE(pat) - VARHDRSZ);
- if (pg_database_encoding_max_length() == 1)
- result = (MatchText(s, slen, p, plen) != LIKE_TRUE);
- else
- result = (MBMatchText(s, slen, p, plen) != LIKE_TRUE);
+ result = (GenericMatchText(s, slen, p, plen) != LIKE_TRUE);
PG_RETURN_BOOL(result);
}
@@ -186,10 +205,7 @@ textlike(PG_FUNCTION_ARGS)
p = VARDATA(pat);
plen = (VARSIZE(pat) - VARHDRSZ);
- if (pg_database_encoding_max_length() == 1)
- result = (MatchText(s, slen, p, plen) == LIKE_TRUE);
- else
- result = (MBMatchText(s, slen, p, plen) == LIKE_TRUE);
+ result = (GenericMatchText(s, slen, p, plen) == LIKE_TRUE);
PG_RETURN_BOOL(result);
}
@@ -210,10 +226,7 @@ textnlike(PG_FUNCTION_ARGS)
p = VARDATA(pat);
plen = (VARSIZE(pat) - VARHDRSZ);
- if (pg_database_encoding_max_length() == 1)
- result = (MatchText(s, slen, p, plen) != LIKE_TRUE);
- else
- result = (MBMatchText(s, slen, p, plen) != LIKE_TRUE);
+ result = (GenericMatchText(s, slen, p, plen) != LIKE_TRUE);
PG_RETURN_BOOL(result);
}
@@ -234,7 +247,7 @@ bytealike(PG_FUNCTION_ARGS)
p = VARDATA(pat);
plen = (VARSIZE(pat) - VARHDRSZ);
- result = (MatchBytea(s, slen, p, plen) == LIKE_TRUE);
+ result = (SB_MatchText(s, slen, p, plen) == LIKE_TRUE);
PG_RETURN_BOOL(result);
}
@@ -255,7 +268,7 @@ byteanlike(PG_FUNCTION_ARGS)
p = VARDATA(pat);
plen = (VARSIZE(pat) - VARHDRSZ);
- result = (MatchBytea(s, slen, p, plen) != LIKE_TRUE);
+ result = (SB_MatchText(s, slen, p, plen) != LIKE_TRUE);
PG_RETURN_BOOL(result);
}
@@ -270,37 +283,11 @@ nameiclike(PG_FUNCTION_ARGS)
Name str = PG_GETARG_NAME(0);
text *pat = PG_GETARG_TEXT_P(1);
bool result;
- char *s,
- *p;
- int slen,
- plen;
-
- if (pg_database_encoding_max_length() == 1)
- {
- s = NameStr(*str);
- slen = strlen(s);
- p = VARDATA(pat);
- plen = (VARSIZE(pat) - VARHDRSZ);
- result = (MatchTextIC(s, slen, p, plen) == LIKE_TRUE);
- }
- else
- {
- /* Force inputs to lower case to achieve case insensitivity */
- text *strtext;
+ text *strtext;
- strtext = DatumGetTextP(DirectFunctionCall1(name_text,
+ strtext = DatumGetTextP(DirectFunctionCall1(name_text,
NameGetDatum(str)));
- strtext = DatumGetTextP(DirectFunctionCall1(lower,
- PointerGetDatum(strtext)));
- pat = DatumGetTextP(DirectFunctionCall1(lower,
- PointerGetDatum(pat)));
-
- s = VARDATA(strtext);
- slen = (VARSIZE(strtext) - VARHDRSZ);
- p = VARDATA(pat);
- plen = (VARSIZE(pat) - VARHDRSZ);
- result = (MBMatchTextIC(s, slen, p, plen) == LIKE_TRUE);
- }
+ result = (Generic_Text_IC_like(strtext, pat) == LIKE_TRUE);
PG_RETURN_BOOL(result);
}
@@ -311,37 +298,11 @@ nameicnlike(PG_FUNCTION_ARGS)
Name str = PG_GETARG_NAME(0);
text *pat = PG_GETARG_TEXT_P(1);
bool result;
- char *s,
- *p;
- int slen,
- plen;
-
- if (pg_database_encoding_max_length() == 1)
- {
- s = NameStr(*str);
- slen = strlen(s);
- p = VARDATA(pat);
- plen = (VARSIZE(pat) - VARHDRSZ);
- result = (MatchTextIC(s, slen, p, plen) != LIKE_TRUE);
- }
- else
- {
- /* Force inputs to lower case to achieve case insensitivity */
- text *strtext;
+ text *strtext;
- strtext = DatumGetTextP(DirectFunctionCall1(name_text,
+ strtext = DatumGetTextP(DirectFunctionCall1(name_text,
NameGetDatum(str)));
- strtext = DatumGetTextP(DirectFunctionCall1(lower,
- PointerGetDatum(strtext)));
- pat = DatumGetTextP(DirectFunctionCall1(lower,
- PointerGetDatum(pat)));
-
- s = VARDATA(strtext);
- slen = (VARSIZE(strtext) - VARHDRSZ);
- p = VARDATA(pat);
- plen = (VARSIZE(pat) - VARHDRSZ);
- result = (MBMatchTextIC(s, slen, p, plen) != LIKE_TRUE);
- }
+ result = (Generic_Text_IC_like(strtext, pat) != LIKE_TRUE);
PG_RETURN_BOOL(result);
}
@@ -352,32 +313,8 @@ texticlike(PG_FUNCTION_ARGS)
text *str = PG_GETARG_TEXT_P(0);
text *pat = PG_GETARG_TEXT_P(1);
bool result;
- char *s,
- *p;
- int slen,
- plen;
- if (pg_database_encoding_max_length() == 1)
- {
- s = VARDATA(str);
- slen = (VARSIZE(str) - VARHDRSZ);
- p = VARDATA(pat);
- plen = (VARSIZE(pat) - VARHDRSZ);
- result = (MatchTextIC(s, slen, p, plen) == LIKE_TRUE);
- }
- else
- {
- /* Force inputs to lower case to achieve case insensitivity */
- str = DatumGetTextP(DirectFunctionCall1(lower,
- PointerGetDatum(str)));
- pat = DatumGetTextP(DirectFunctionCall1(lower,
- PointerGetDatum(pat)));
- s = VARDATA(str);
- slen = (VARSIZE(str) - VARHDRSZ);
- p = VARDATA(pat);
- plen = (VARSIZE(pat) - VARHDRSZ);
- result = (MBMatchTextIC(s, slen, p, plen) == LIKE_TRUE);
- }
+ result = (Generic_Text_IC_like(str, pat) == LIKE_TRUE);
PG_RETURN_BOOL(result);
}
@@ -388,32 +325,8 @@ texticnlike(PG_FUNCTION_ARGS)
text *str = PG_GETARG_TEXT_P(0);
text *pat = PG_GETARG_TEXT_P(1);
bool result;
- char *s,
- *p;
- int slen,
- plen;
- if (pg_database_encoding_max_length() == 1)
- {
- s = VARDATA(str);
- slen = (VARSIZE(str) - VARHDRSZ);
- p = VARDATA(pat);
- plen = (VARSIZE(pat) - VARHDRSZ);
- result = (MatchTextIC(s, slen, p, plen) != LIKE_TRUE);
- }
- else
- {
- /* Force inputs to lower case to achieve case insensitivity */
- str = DatumGetTextP(DirectFunctionCall1(lower,
- PointerGetDatum(str)));
- pat = DatumGetTextP(DirectFunctionCall1(lower,
- PointerGetDatum(pat)));
- s = VARDATA(str);
- slen = (VARSIZE(str) - VARHDRSZ);
- p = VARDATA(pat);
- plen = (VARSIZE(pat) - VARHDRSZ);
- result = (MBMatchTextIC(s, slen, p, plen) != LIKE_TRUE);
- }
+ result = (Generic_Text_IC_like(str, pat) != LIKE_TRUE);
PG_RETURN_BOOL(result);
}
@@ -430,7 +343,7 @@ like_escape(PG_FUNCTION_ARGS)
text *result;
if (pg_database_encoding_max_length() == 1)
- result = do_like_escape(pat, esc);
+ result = SB_do_like_escape(pat, esc);
else
result = MB_do_like_escape(pat, esc);
@@ -446,179 +359,8 @@ like_escape_bytea(PG_FUNCTION_ARGS)
{
bytea *pat = PG_GETARG_BYTEA_P(0);
bytea *esc = PG_GETARG_BYTEA_P(1);
- bytea *result;
- 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.
- */
- 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++ = '\\';
- BYTEA_CopyAdvChar(r, p, plen);
- }
- }
- else
- {
- /*
- * The specified escape must be only a single character.
- */
- BYTEA_NextChar(e, elen);
- if (elen != 0)
- ereport(ERROR,
- (errcode(ERRCODE_INVALID_ESCAPE_SEQUENCE),
- errmsg("invalid escape string"),
- errhint("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_BYTEA_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 (BYTEA_CHAREQ(p, e) && !afterescape)
- {
- *r++ = '\\';
- BYTEA_NextChar(p, plen);
- afterescape = true;
- }
- else if (*p == '\\')
- {
- *r++ = '\\';
- if (!afterescape)
- *r++ = '\\';
- BYTEA_NextChar(p, plen);
- afterescape = false;
- }
- else
- {
- BYTEA_CopyAdvChar(r, p, plen);
- afterescape = false;
- }
- }
- }
-
- SET_VARSIZE(result, r - ((char *) result));
+ bytea *result = SB_do_like_escape((text *)pat, (text *)esc);
- PG_RETURN_BYTEA_P(result);
+ PG_RETURN_BYTEA_P((bytea *)result);
}
-/*
- * Same as above, but specifically for bytea (binary) datatype
- */
-static int
-MatchBytea(char *t, int tlen, char *p, int plen)
-{
- /* Fast path for match-everything pattern */
- if ((plen == 1) && (*p == '%'))
- return LIKE_TRUE;
-
- while ((tlen > 0) && (plen > 0))
- {
- if (*p == '\\')
- {
- /* Next pattern char must match literally, whatever it is */
- BYTEA_NextChar(p, plen);
- if ((plen <= 0) || !BYTEA_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 == '%'))
- BYTEA_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 (BYTEA_CHAREQ(t, p) || (*p == '\\') || (*p == '_'))
- {
- int matched = MatchBytea(t, tlen, p, plen);
-
- if (matched != LIKE_FALSE)
- return matched; /* TRUE or ABORT */
- }
-
- BYTEA_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 != '_') && !BYTEA_CHAREQ(t, p))
- {
- /*
- * Not the single-character wildcard and no explicit match? Then
- * time to quit...
- */
- return LIKE_FALSE;
- }
-
- BYTEA_NextChar(t, tlen);
- BYTEA_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 */
- BYTEA_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;
-} /* MatchBytea() */
diff --git a/src/backend/utils/adt/like_match.c b/src/backend/utils/adt/like_match.c
index 22e2705fb36..62f8bc40a15 100644
--- a/src/backend/utils/adt/like_match.c
+++ b/src/backend/utils/adt/like_match.c
@@ -3,23 +3,21 @@
* like_match.c
* like expression handling internal code.
*
- * This file is included by like.c *twice*, to provide an optimization
- * for single-byte encodings.
+ * This file is included by like.c three times, to provide natching code for
+ * single-byte encodings, UTF8, and for other multi-byte encodings.
+ * UTF8 is a special case because we can use a much more efficient version
+ * of NextChar than can be used for other multi-byte encodings.
*
* Before the inclusion, we need to define following macros:
*
- * CHAREQ
- * ICHAREQ
- * NextChar
- * CopyAdvChar
- * MatchText (MBMatchText)
- * MatchTextIC (MBMatchTextIC)
- * do_like_escape (MB_do_like_escape)
+ * NextChar
+ * MatchText - to name of function wanted
+ * do_like_escape - name of function if wanted - needs CHAREQ and CopyAdvChar
*
* Copyright (c) 1996-2007, PostgreSQL Global Development Group
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/adt/like_match.c,v 1.15 2007/02/27 23:48:08 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/like_match.c,v 1.16 2007/06/02 02:03:42 adunstan Exp $
*
*-------------------------------------------------------------------------
*/
@@ -77,21 +75,36 @@ MatchText(char *t, int tlen, char *p, int plen)
if ((plen == 1) && (*p == '%'))
return LIKE_TRUE;
+ /*
+ * In this loop, we advance by char when matching wildcards (and thus
+ * on recursive entry to this function we are properly char-synced). On
+ * other occasions it is safe to advance by byte, as the text and pattern
+ * will be in lockstep. This allows us to perform all comparisons between
+ * the text and pattern on a byte by byte basis, even for multi-byte
+ * encodings.
+ */
+
while ((tlen > 0) && (plen > 0))
{
if (*p == '\\')
{
- /* Next pattern char must match literally, whatever it is */
- NextChar(p, plen);
- if ((plen <= 0) || !CHAREQ(t, p))
+ /* Next byte must match literally, whatever it is */
+ NextByte(p, plen);
+ if ((plen <= 0) || *p != *t )
return LIKE_FALSE;
}
else if (*p == '%')
{
+ /*
+ * % processing is essentially a search for a match for what
+ * follows the %, plus a recursive match of the remainder.
+ * We succeed if and only if both conditions are met.
+ */
+
/* %% is the same as % according to the SQL standard */
/* Advance past all %'s */
while ((plen > 0) && (*p == '%'))
- NextChar(p, plen);
+ NextByte(p, plen);
/* Trailing percent matches everything. */
if (plen <= 0)
return LIKE_TRUE;
@@ -100,107 +113,62 @@ MatchText(char *t, int tlen, char *p, int plen)
* 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 == '\\') || (*p == '_'))
- {
- int matched = MatchText(t, tlen, p, plen);
+ if (*p == '_')
- if (matched != LIKE_FALSE)
- return matched; /* TRUE or ABORT */
- }
+ {
+ /* %_ is the same as _% - avoid matching _ repeatedly */
NextChar(t, tlen);
- }
+ NextByte(p, plen);
- /*
- * 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 */
+ if (tlen <= 0)
+ {
+ return (plen <= 0) ? LIKE_TRUE : LIKE_ABORT;
+ }
+ else if (plen <= 0)
+ {
+ return LIKE_FALSE;
+ }
- /* 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;
+ while (tlen > 0)
+ {
+ int matched = MatchText(t, tlen, p, plen);
+
+ if (matched != LIKE_FALSE)
+ return matched; /* TRUE or ABORT */
- /*
- * End of text with no match, so no point in trying later places to start
- * matching this pattern.
- */
- return LIKE_ABORT;
-} /* MatchText() */
+ NextChar(t, tlen);
+ }
+ }
+ else
+ {
-/*
- * Same as above, but ignore case
- */
-static int
-MatchTextIC(char *t, int tlen, char *p, int plen)
-{
- /* Fast path for match-everything pattern */
- if ((plen == 1) && (*p == '%'))
- return LIKE_TRUE;
+ char firstpat = *p ;
- while ((tlen > 0) && (plen > 0))
- {
- if (*p == '\\')
- {
- /* Next pattern char must match literally, whatever it is */
- 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;
+ if (*p == '\\')
+ {
+ if (plen < 2)
+ return LIKE_FALSE;
+ firstpat = p[1];
+ }
- /*
- * 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 == '\\') || (*p == '_'))
+ while (tlen > 0)
{
- int matched = MatchTextIC(t, tlen, p, plen);
+ /*
+ * Optimization to prevent most recursion: don't recurse
+ * unless first pattern byte matches first text byte.
+ */
+ if (*t == firstpat)
+ {
+ int matched = MatchText(t, tlen, p, plen);
+
+ if (matched != LIKE_FALSE)
+ return matched; /* TRUE or ABORT */
+ }
+
+ NextChar(t, tlen);
- if (matched != LIKE_FALSE)
- return matched; /* TRUE or ABORT */
}
-
- NextChar(t, tlen);
}
/*
@@ -209,7 +177,13 @@ MatchTextIC(char *t, int tlen, char *p, int plen)
*/
return LIKE_ABORT;
}
- else if ((*p != '_') && !ICHAREQ(t, p))
+ else if (*p == '_')
+ {
+ NextChar(t, tlen);
+ NextByte(p, plen);
+ continue;
+ }
+ else if (*t != *p)
{
/*
* Not the single-character wildcard and no explicit match? Then
@@ -217,9 +191,20 @@ MatchTextIC(char *t, int tlen, char *p, int plen)
*/
return LIKE_FALSE;
}
-
- NextChar(t, tlen);
- NextChar(p, plen);
+ /*
+ * It is safe to use NextByte instead of NextChar here, even for
+ * multi-byte character sets, because we are not following
+ * immediately after a wildcard character.
+ * If we are in the middle of a multibyte character, we must
+ * already have matched at least one byte of the character from
+ * both text and pattern; so we cannot get out-of-sync
+ * on character boundaries. And we know that no backend-legal
+ * encoding allows ASCII characters such as '%' to appear as
+ * non-first bytes of characters, so we won't mistakenly detect
+ * a new wildcard.
+ */
+ NextByte(t, tlen);
+ NextByte(p, plen);
}
if (tlen > 0)
@@ -228,7 +213,8 @@ MatchTextIC(char *t, int tlen, char *p, int plen)
/* End of input string. Do we have matching pattern remaining? */
while ((plen > 0) && (*p == '%')) /* allow multiple %'s at end of
* pattern */
- NextChar(p, plen);
+ NextByte(p, plen);
+
if (plen <= 0)
return LIKE_TRUE;
@@ -237,12 +223,14 @@ MatchTextIC(char *t, int tlen, char *p, int plen)
* matching this pattern.
*/
return LIKE_ABORT;
-} /* MatchTextIC() */
+} /* MatchText() */
/*
* like_escape() --- given a pattern and an ESCAPE string,
* convert the pattern to use Postgres' standard backslash escape convention.
*/
+#ifdef do_like_escape
+
static text *
do_like_escape(text *pat, text *esc)
{
@@ -336,3 +324,17 @@ do_like_escape(text *pat, text *esc)
return result;
}
+#endif /* do_like_escape */
+
+#ifdef CHAREQ
+#undef CHAREQ
+#endif
+
+#undef NextChar
+#undef CopyAdvChar
+#undef MatchText
+
+#ifdef do_like_escape
+#undef do_like_escape
+#endif
+
--
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