LIKE cleanup.

diff --git a/src/backend/utils/adt/like.c b/src/backend/utils/adt/like.c
index e3d37739a9f99d9325816e5d9a07a0dc9944b31f..6057fa2f1542bd928008cf05efbe236de30a447f 100644 (file)
--- 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: 1.22 $
+/* $Revision: 1.23 $
 ** "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.
@@ -150,10 +150,8 @@ DoMatch(pg_wchar *text, pg_wchar *p)
 {
    int         matched;
 
-   for (; *p; text ++, p++)
+   for (; *p && *text; text++, p++)
    {
-       if (*text == '\0' && *p != '%')
-           return LIKE_ABORT;
        switch (*p)
        {
            case '\\':
@@ -161,27 +159,43 @@ DoMatch(pg_wchar *text, pg_wchar *p)
                p++;
                /* FALLTHROUGH */
            default:
-               if (*text !=*p)
+               if (*text != *p)
                    return LIKE_FALSE;
-               continue;
+               break;
            case '_':
                /* Match anything. */
-               continue;
+               break;
            case '%':
-               while (*++p == '%')
-                   /* Consecutive percents act just like one. */
-                   continue;
+               /* %% is the same as % according to the SQL standard */
+               /* Advance past all %'s */
+               while (*p == '%')
+                   p++;
                if (*p == '\0')
                    /* Trailing percent matches everything. */
                    return LIKE_TRUE;
                while (*text)
-                   if ((matched = DoMatch(text ++, p)) != LIKE_FALSE)
+               {
+                   /* Optimization to prevent most recursion */
+                   if ((*text == *p ||
+                        *p == '\\' || *p == '%' || *p == '_') &&
+                       (matched = DoMatch(text, p)) != LIKE_FALSE)
                        return matched;
+                   text++;
+               }
                return LIKE_ABORT;
        }
    }
 
-   return *text == '\0';
+   if (*text != '\0')
+       return LIKE_ABORT;
+   else
+   {
+       /* End of input string.  Do we have matching string remaining? */
+       if (p[0] == '\0' || (p[0] == '%' && p[1] == '\0'))
+           return LIKE_TRUE;
+       else
+           return LIKE_ABORT;
+   }
 }