Fix (I think) broken usage of MultiByteToWideChar. I had missed the

subtlety that this function only returns a null terminator if it's
fed input that includes one; which, in the usage here, it's not.
This probably fixes bugs reported by Thomas Haegi.

diff --git a/src/backend/tsearch/ts_locale.c b/src/backend/tsearch/ts_locale.c
index acec56bfeb229ec8f751dd94525cbd82c98e4b10..8a34cc5269a7b5f14d94a569a2d30c9dbf656a34 100644 (file)
--- a/src/backend/tsearch/ts_locale.c
+++ b/src/backend/tsearch/ts_locale.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/tsearch/ts_locale.c,v 1.4 2007/11/15 21:14:38 momjian Exp $
+ *   $PostgreSQL: pgsql/src/backend/tsearch/ts_locale.c,v 1.5 2007/11/24 21:20:07 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -23,7 +23,7 @@
  * wchar2char --- convert wide characters to multibyte format
  *
  * This has the same API as the standard wcstombs() function; in particular,
- * tolen is the maximum number of bytes to store at *to, and *from should be
+ * tolen is the maximum number of bytes to store at *to, and *from must be
  * zero-terminated.  The output will be zero-terminated iff there is room.
  */
 size_t
@@ -73,21 +73,28 @@ char2wchar(wchar_t *to, size_t tolen, const char *from, size_t fromlen)
    {
        int         r;
 
-       r = MultiByteToWideChar(CP_UTF8, 0, from, fromlen, to, tolen);
-
-       if (r <= 0)
+       /* stupid Microsloth API does not work for zero-length input */
+       if (fromlen == 0)
+           r = 0;
+       else
        {
-           pg_verifymbstr(from, fromlen, false);
-           ereport(ERROR,
-                   (errcode(ERRCODE_CHARACTER_NOT_IN_REPERTOIRE),
-                    errmsg("invalid multibyte character for locale"),
-                    errhint("The server's LC_CTYPE locale is probably incompatible with the database encoding.")));
+           r = MultiByteToWideChar(CP_UTF8, 0, from, fromlen, to, tolen - 1);
+
+           if (r <= 0)
+           {
+               /* see notes in oracle_compat.c about error reporting */
+               pg_verifymbstr(from, fromlen, false);
+               ereport(ERROR,
+                       (errcode(ERRCODE_CHARACTER_NOT_IN_REPERTOIRE),
+                        errmsg("invalid multibyte character for locale"),
+                        errhint("The server's LC_CTYPE locale is probably incompatible with the database encoding.")));
+           }
        }
 
-       Assert(r <= tolen);
+       Assert(r < tolen);
+       to[r] = 0;
 
-       /* Microsoft counts the zero terminator in the result */
-       return r - 1;
+       return r;
    }
 #endif   /* WIN32 */