Change ILIKE to invoke lower() and then do plain LIKE comparison when

working in a multibyte encoding.  This fixes the problems exhibited in
bug #1931 and other reports of ILIKE misbehavior in UTF8 encoding.
It's a pretty grotty solution though --- should rethink how to do it
after we install better locale support, someday.

diff --git a/src/backend/utils/adt/like.c b/src/backend/utils/adt/like.c
index 4037c28a609f44851a3d8583908e96d3c0bb7df8..e2026218bf523c1fa754e1be0b2ba46e51d9ddc9 100644 (file)
--- 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 1.64 2006/03/05 15:58:42 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/like.c,v 1.65 2006/09/04 18:32:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -64,50 +64,23 @@ wchareq(char *p1, char *p2)
    return 1;
 }
 
-/*--------------------
- * Support routine for MatchTextIC. Compares given multibyte streams
- * as wide characters ignoring case.
- * If they match, returns 1 otherwise returns 0.
- *--------------------
+/*
+ * Formerly we had a routine iwchareq() here that tried to do case-insensitive
+ * comparison of multibyte characters.  It did not work at all, however,
+ * because it relied on tolower() which has a single-byte API ... and
+ * towlower() wouldn't be much better since we have no suitably cheap way
+ * 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 CHARMAX 0x80
-
-static int
-iwchareq(char *p1, char *p2)
-{
-   pg_wchar    c1[2],
-               c2[2];
-   int         l;
-
-   /*
-    * short cut. if *p1 and *p2 is lower than CHARMAX, then we could assume
-    * they are ASCII
-    */
-   if ((unsigned char) *p1 < CHARMAX && (unsigned char) *p2 < CHARMAX)
-       return (tolower((unsigned char) *p1) == tolower((unsigned char) *p2));
-
-   /*
-    * if one of them is an ASCII while the other is not, then they must be
-    * different characters
-    */
-   else if ((unsigned char) *p1 < CHARMAX || (unsigned char) *p2 < CHARMAX)
-       return 0;
-
-   /*
-    * ok, p1 and p2 are both > CHARMAX, then they must be multibyte
-    * characters
-    */
-   l = pg_mblen(p1);
-   (void) pg_mb2wchar_with_len(p1, c1, l);
-   c1[0] = tolower(c1[0]);
-   l = pg_mblen(p2);
-   (void) pg_mb2wchar_with_len(p2, c2, l);
-   c2[0] = tolower(c2[0]);
-   return (c1[0] == c2[0]);
-}
 
+/* Set up to compile like_match.c for multibyte characters */
 #define CHAREQ(p1, p2) wchareq(p1, p2)
-#define ICHAREQ(p1, p2) iwchareq(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) \
@@ -120,7 +93,9 @@ iwchareq(char *p1, char *p2)
 #define MatchText  MBMatchText
 #define MatchTextIC MBMatchTextIC
 #define do_like_escape MB_do_like_escape
+
 #include "like_match.c"
+
 #undef CHAREQ
 #undef ICHAREQ
 #undef NextChar
@@ -129,15 +104,19 @@ iwchareq(char *p1, char *p2)
 #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)--)
-#include "like_match.c"
+
 
 /*
  * interface routines called by the function manager
@@ -296,15 +275,32 @@ nameiclike(PG_FUNCTION_ARGS)
    int         slen,
                plen;
 
-   s = NameStr(*str);
-   slen = strlen(s);
-   p = VARDATA(pat);
-   plen = (VARSIZE(pat) - VARHDRSZ);
-
    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);
 }
@@ -320,15 +316,32 @@ nameicnlike(PG_FUNCTION_ARGS)
    int         slen,
                plen;
 
-   s = NameStr(*str);
-   slen = strlen(s);
-   p = VARDATA(pat);
-   plen = (VARSIZE(pat) - VARHDRSZ);
-
    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);
 }
@@ -344,15 +357,27 @@ texticlike(PG_FUNCTION_ARGS)
    int         slen,
                plen;
 
-   s = VARDATA(str);
-   slen = (VARSIZE(str) - VARHDRSZ);
-   p = VARDATA(pat);
-   plen = (VARSIZE(pat) - VARHDRSZ);
-
    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);
 }
@@ -368,15 +393,27 @@ texticnlike(PG_FUNCTION_ARGS)
    int         slen,
                plen;
 
-   s = VARDATA(str);
-   slen = (VARSIZE(str) - VARHDRSZ);
-   p = VARDATA(pat);
-   plen = (VARSIZE(pat) - VARHDRSZ);
-
    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);
 }