From bad3b3068d97c8acf68958176fa017d5033fe773 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Mon, 7 Jun 1999 14:28:26 +0000
Subject: [PATCH] Repair recently-introduced error in makeIndexable for LIKE: a
non-leading % would be put into the >=/<= patterns. Also, repair
longstanding confusion about whether %% means a literal %%. The SQL92
doesn't say any such thing, and textlike() knows that, but gram.y didn't.
---
src/backend/parser/gram.y | 37 ++++++++++++++++++++++++------------
src/backend/utils/adt/like.c | 6 ++++--
2 files changed, 29 insertions(+), 14 deletions(-)
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index c038f43caae..bb36c6f0422 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.83 1999/05/22 05:06:43 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.84 1999/06/07 14:28:25 tgl Exp $
*
* HISTORY
* AUTHOR DATE MAJOR EVENT
@@ -5357,6 +5357,7 @@ static Node *makeIndexable(char *opname, Node *lexpr, Node *rexpr)
int pos, match_pos=0;
bool found_special = false;
+ /* Cannot optimize if unquoted | { } is present in pattern */
for (pos = 1; n->val.val.str[pos]; pos++)
{
if (n->val.val.str[pos] == '|' ||
@@ -5367,12 +5368,16 @@ static Node *makeIndexable(char *opname, Node *lexpr, Node *rexpr)
break;
}
if (n->val.val.str[pos] == '\\')
+ {
pos++;
+ if (n->val.val.str[pos] == '\0')
+ break;
+ }
}
- /* skip leading ^ */
if (!found_special)
{
+ /* note start at pos 1 to skip leading ^ */
for (pos = 1; n->val.val.str[pos]; pos++)
{
if (n->val.val.str[pos] == '.' ||
@@ -5383,9 +5388,11 @@ static Node *makeIndexable(char *opname, Node *lexpr, Node *rexpr)
(strcmp(opname,"~*") == 0 && isalpha(n->val.val.str[pos])))
break;
if (n->val.val.str[pos] == '\\')
+ {
pos++;
- if (n->val.val.str[pos] == '\0')
- break;
+ if (n->val.val.str[pos] == '\0')
+ break;
+ }
match_least[match_pos] = n->val.val.str[pos];
match_most[match_pos++] = n->val.val.str[pos];
}
@@ -5430,16 +5437,22 @@ static Node *makeIndexable(char *opname, Node *lexpr, Node *rexpr)
for (pos = 0; n->val.val.str[pos]; pos++)
{
- if (n->val.val.str[pos] == '%' &&
- n->val.val.str[pos+1] != '%')
- break;
- if(n->val.val.str[pos] == '_')
+ /* % and _ are wildcard characters in LIKE */
+ if (n->val.val.str[pos] == '%' ||
+ n->val.val.str[pos] == '_')
break;
- if (n->val.val.str[pos] == '\\' ||
- n->val.val.str[pos+1] == '%')
+ /* Backslash quotes the next character */
+ if (n->val.val.str[pos] == '\\')
+ {
pos++;
- if (n->val.val.str[pos] == '\0')
- break;
+ if (n->val.val.str[pos] == '\0')
+ break;
+ }
+ /*
+ * NOTE: this code used to think that %% meant a literal %,
+ * but textlike() itself does not think that, and the SQL92
+ * spec doesn't say any such thing either.
+ */
match_least[match_pos] = n->val.val.str[pos];
match_most[match_pos++] = n->val.val.str[pos];
}
diff --git a/src/backend/utils/adt/like.c b/src/backend/utils/adt/like.c
index 14fc5314d0c..2d35bfabaca 100644
--- a/src/backend/utils/adt/like.c
+++ b/src/backend/utils/adt/like.c
@@ -111,7 +111,7 @@ textnlike(struct varlena * s, struct varlena * p)
}
-/* $Revision: 1.24 $
+/* $Revision: 1.25 $
** "like.c" A first attempt at a LIKE operator for Postgres95.
**
** Originally written by Rich $alz, mirror!rs, Wed Nov 26 19:03:17 EST 1986.
@@ -191,7 +191,9 @@ DoMatch(pg_wchar * text, pg_wchar * p)
else
{
/* End of input string. Do we have matching string remaining? */
- if (p[0] == '\0' || (p[0] == '%' && p[1] == '\0'))
+ while (*p == '%') /* allow multiple %'s at end of pattern */
+ p++;
+ if (*p == '\0')
return LIKE_TRUE;
else
return LIKE_ABORT;
--
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