diff options
| -rw-r--r-- | src/backend/utils/adt/like.c | 38 |
1 files changed, 26 insertions, 12 deletions
diff --git a/src/backend/utils/adt/like.c b/src/backend/utils/adt/like.c index e3d37739a9f..6057fa2f154 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: 1.22 $ +/* $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; + } } |