Re: [HACKERS] like/ilike improvements - Mailing list pgsql-patches
| From | Andrew Dunstan |
|---|---|
| Subject | Re: [HACKERS] like/ilike improvements |
| Date | |
| Msg-id | 465F94F2.1070707@dunslane.net Whole thread Raw |
| Responses |
Re: [HACKERS] like/ilike improvements
Re: [HACKERS] like/ilike improvements |
| List | pgsql-patches |
Tom Lane wrote:
> Andrew Dunstan <andrew@dunslane.net> writes:
>
>> do { (t)++; (tlen)--} while ((*(t) & 0xC0) == 0x80 && tlen > 0)
>>
>
> The while *must* test those two conditions in the other order.
> (Don't laugh --- we've had reproducible bugs before in which the backend
> dumped core because of running off the end of memory due to this type
> of mistake.)
>
>
>> In fact, I'm wondering if that might make the other UTF8 stuff redundant
>> - the whole point of what we're doing is to avoid expensive calls to
>> NextChar;
>>
>
> +1 I think. This test will be approximately the same expense as what
> the outer loop would otherwise be (tlen > 0 and *t != firstpat), and
> doing it this way removes an entire layer of intellectual complexity.
> Even though the code is hardly different, we are no longer dealing in
> misaligned pointers anywhere in the match algorithm.
>
>
>
OK, here is a patch that I think incorporates all the ideas discussed
(including part of Mark Mielke's suggestion about optimising %_). There
is now no special treatment of UTF8 other than its use of a faster
NextChar macro.
cheers
andrew
Index: src/backend/utils/adt/like.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/utils/adt/like.c,v
retrieving revision 1.68
diff -c -r1.68 like.c
*** src/backend/utils/adt/like.c 27 Feb 2007 23:48:08 -0000 1.68
--- src/backend/utils/adt/like.c 1 Jun 2007 02:21:59 -0000
***************
*** 28,48 ****
#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 MBMatchText(char *t, int tlen, char *p, int plen);
! static int MBMatchTextIC(char *t, int tlen, char *p, int plen);
static text *MB_do_like_escape(text *, text *);
/*--------------------
* Support routine for MatchText. Compares given multibyte streams
* as wide characters. If they match, returns 1 otherwise returns 0.
*--------------------
*/
! static int
wchareq(char *p1, char *p2)
{
int p1_len;
--- 28,50 ----
#define LIKE_ABORT (-1)
! static int SB_MatchText(char *t, int tlen, char *p, int plen);
! static text *SB_do_like_escape(text *, text *);
! 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 inline int
wchareq(char *p1, char *p2)
{
int p1_len;
***************
*** 72,86 ****
* 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.
*/
/* 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 NextChar(p, plen) \
do { int __l = pg_mblen(p); (p) +=__l; (plen) -=__l; } while (0)
#define CopyAdvChar(dst, src, srclen) \
--- 74,85 ----
* 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.
*/
+ #define NextByte(p, plen) ((p)++, (plen)--)
+
/* Set up to compile like_match.c for multibyte characters */
! #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) \
***************
*** 90,122 ****
*(dst)++ = *(src)++; \
} while (0)
! #define MatchText MBMatchText
! #define MatchTextIC MBMatchTextIC
#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 CopyAdvChar(dst, src, srclen) (*(dst)++ = *(src)++, (srclen)--)
#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)--)
/*
* interface routines called by the function manager
--- 89,147 ----
*(dst)++ = *(src)++; \
} while (0)
! #define MatchText MB_MatchText
#define do_like_escape MB_do_like_escape
#include "like_match.c"
/* Set up to compile like_match.c for single-byte characters */
#define CHAREQ(p1, p2) (*(p1) == *(p2))
! #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"
+
+ 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
***************
*** 138,147 ****
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);
PG_RETURN_BOOL(result);
}
--- 163,169 ----
p = VARDATA(pat);
plen = (VARSIZE(pat) - VARHDRSZ);
! result = (GenericMatchText(s, slen, p, plen) == LIKE_TRUE);
PG_RETURN_BOOL(result);
}
***************
*** 162,171 ****
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);
PG_RETURN_BOOL(result);
}
--- 184,190 ----
p = VARDATA(pat);
plen = (VARSIZE(pat) - VARHDRSZ);
! result = (GenericMatchText(s, slen, p, plen) != LIKE_TRUE);
PG_RETURN_BOOL(result);
}
***************
*** 186,195 ****
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);
PG_RETURN_BOOL(result);
}
--- 205,211 ----
p = VARDATA(pat);
plen = (VARSIZE(pat) - VARHDRSZ);
! result = (GenericMatchText(s, slen, p, plen) == LIKE_TRUE);
PG_RETURN_BOOL(result);
}
***************
*** 210,219 ****
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);
PG_RETURN_BOOL(result);
}
--- 226,232 ----
p = VARDATA(pat);
plen = (VARSIZE(pat) - VARHDRSZ);
! result = (GenericMatchText(s, slen, p, plen) != LIKE_TRUE);
PG_RETURN_BOOL(result);
}
***************
*** 234,240 ****
p = VARDATA(pat);
plen = (VARSIZE(pat) - VARHDRSZ);
! result = (MatchBytea(s, slen, p, plen) == LIKE_TRUE);
PG_RETURN_BOOL(result);
}
--- 247,253 ----
p = VARDATA(pat);
plen = (VARSIZE(pat) - VARHDRSZ);
! result = (SB_MatchText(s, slen, p, plen) == LIKE_TRUE);
PG_RETURN_BOOL(result);
}
***************
*** 255,261 ****
p = VARDATA(pat);
plen = (VARSIZE(pat) - VARHDRSZ);
! result = (MatchBytea(s, slen, p, plen) != LIKE_TRUE);
PG_RETURN_BOOL(result);
}
--- 268,274 ----
p = VARDATA(pat);
plen = (VARSIZE(pat) - VARHDRSZ);
! result = (SB_MatchText(s, slen, p, plen) != LIKE_TRUE);
PG_RETURN_BOOL(result);
}
***************
*** 270,306 ****
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;
! 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);
! }
PG_RETURN_BOOL(result);
}
--- 283,293 ----
Name str = PG_GETARG_NAME(0);
text *pat = PG_GETARG_TEXT_P(1);
bool result;
! text *strtext;
! strtext = DatumGetTextP(DirectFunctionCall1(name_text,
NameGetDatum(str)));
! result = (Generic_Text_IC_like(strtext, pat) == LIKE_TRUE);
PG_RETURN_BOOL(result);
}
***************
*** 311,347 ****
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;
! 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);
! }
PG_RETURN_BOOL(result);
}
--- 298,308 ----
Name str = PG_GETARG_NAME(0);
text *pat = PG_GETARG_TEXT_P(1);
bool result;
! text *strtext;
! strtext = DatumGetTextP(DirectFunctionCall1(name_text,
NameGetDatum(str)));
! result = (Generic_Text_IC_like(strtext, pat) != LIKE_TRUE);
PG_RETURN_BOOL(result);
}
***************
*** 352,383 ****
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);
! }
PG_RETURN_BOOL(result);
}
--- 313,320 ----
text *str = PG_GETARG_TEXT_P(0);
text *pat = PG_GETARG_TEXT_P(1);
bool result;
! result = (Generic_Text_IC_like(str, pat) == LIKE_TRUE);
PG_RETURN_BOOL(result);
}
***************
*** 388,419 ****
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);
! }
PG_RETURN_BOOL(result);
}
--- 325,332 ----
text *str = PG_GETARG_TEXT_P(0);
text *pat = PG_GETARG_TEXT_P(1);
bool result;
! result = (Generic_Text_IC_like(str, pat) != LIKE_TRUE);
PG_RETURN_BOOL(result);
}
***************
*** 430,436 ****
text *result;
if (pg_database_encoding_max_length() == 1)
! result = do_like_escape(pat, esc);
else
result = MB_do_like_escape(pat, esc);
--- 343,349 ----
text *result;
if (pg_database_encoding_max_length() == 1)
! result = SB_do_like_escape(pat, esc);
else
result = MB_do_like_escape(pat, esc);
***************
*** 446,624 ****
{
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));
! PG_RETURN_BYTEA_P(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() */
--- 359,366 ----
{
bytea *pat = PG_GETARG_BYTEA_P(0);
bytea *esc = PG_GETARG_BYTEA_P(1);
! bytea *result = SB_do_like_escape((text *)pat, (text *)esc);
! PG_RETURN_BYTEA_P((bytea *)result);
}
Index: src/backend/utils/adt/like_match.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/utils/adt/like_match.c,v
retrieving revision 1.15
diff -c -r1.15 like_match.c
*** src/backend/utils/adt/like_match.c 27 Feb 2007 23:48:08 -0000 1.15
--- src/backend/utils/adt/like_match.c 1 Jun 2007 02:21:59 -0000
***************
*** 3,20 ****
* like_match.c
* like expression handling internal code.
*
! * This file is included by like.c *twice*, to provide an optimization
! * for single-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)
*
* Copyright (c) 1996-2007, PostgreSQL Global Development Group
*
--- 3,18 ----
* like_match.c
* like expression handling internal code.
*
! * 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:
*
! * 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
*
***************
*** 81,97 ****
{
if (*p == '\\')
{
! /* Next pattern char must match literally, whatever it is */
! 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;
--- 79,101 ----
{
if (*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 == '%'))
! NextByte(p, plen);
/* Trailing percent matches everything. */
if (plen <= 0)
return LIKE_TRUE;
***************
*** 100,206 ****
* 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 (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() */
! /*
! * 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;
! 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;
! /*
! * 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 == '_'))
{
! int matched = MatchTextIC(t, tlen, p, plen);
! if (matched != LIKE_FALSE)
! return matched; /* TRUE or ABORT */
! }
! NextChar(t, tlen);
}
/*
--- 104,165 ----
* Otherwise, scan for a text position at which we can match the
* rest of the pattern.
*/
! if (*p == '_')
! {
! /* %_ is the same as _% - avoid matching _ repeatedly */
NextChar(t, tlen);
! NextByte(p, plen);
! if (tlen == 0)
! {
! return (plen == 0) ? LIKE_TRUE : LIKE_ABORT;
! }
! else if (plen == 0)
! {
! return LIKE_FALSE;
! }
! while (tlen > 0)
! {
! int matched = MatchText(t, tlen, p, plen);
!
! if (matched != LIKE_FALSE)
! return matched; /* TRUE or ABORT */
! NextChar(t, tlen);
! }
! }
! else
! {
! char firstpat = *p ;
! if (*p == '\\')
! {
! if (plen < 2)
! return LIKE_FALSE;
! firstpat = p[1];
! }
! while (tlen > 0)
{
! /*
! * 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);
! }
}
/*
***************
*** 209,215 ****
*/
return LIKE_ABORT;
}
! else if ((*p != '_') && !ICHAREQ(t, p))
{
/*
* Not the single-character wildcard and no explicit match? Then
--- 168,180 ----
*/
return LIKE_ABORT;
}
! else if (*p == '_')
! {
! NextChar(t, tlen);
! NextByte(p, plen);
! continue;
! }
! else if (*t != *p)
{
/*
* Not the single-character wildcard and no explicit match? Then
***************
*** 217,225 ****
*/
return LIKE_FALSE;
}
!
! NextChar(t, tlen);
! NextChar(p, plen);
}
if (tlen > 0)
--- 182,194 ----
*/
return LIKE_FALSE;
}
! /*
! * 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.
! */
! NextByte(t, tlen);
! NextByte(p, plen);
}
if (tlen > 0)
***************
*** 228,234 ****
/* 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;
--- 197,204 ----
/* End of input string. Do we have matching pattern remaining? */
while ((plen > 0) && (*p == '%')) /* allow multiple %'s at end of
* pattern */
! NextByte(p, plen);
!
if (plen <= 0)
return LIKE_TRUE;
***************
*** 237,248 ****
* matching this pattern.
*/
return LIKE_ABORT;
! } /* MatchTextIC() */
/*
* like_escape() --- given a pattern and an ESCAPE string,
* convert the pattern to use Postgres' standard backslash escape convention.
*/
static text *
do_like_escape(text *pat, text *esc)
{
--- 207,220 ----
* matching this pattern.
*/
return LIKE_ABORT;
! } /* 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)
{
***************
*** 336,338 ****
--- 308,324 ----
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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