Remove mbfl_strlen call when offset is positive in strpos functions

Author: Girgias

ext/mbstring/mbstring.c

@@ -2100,12 +2100,10 @@ PHP_FUNCTION(mb_strpos)
 		RETURN_THROWS();
 	}
 
-	if (offset != 0) {
+	if (offset < 0) {
 		size_t slen = mbfl_strlen(&haystack);
+		offset += slen;
 		if (offset < 0) {
-			offset += slen;
-		}
-		if (offset < 0 || offset > slen) {
 			zend_value_error("Offset not contained in string");
 			RETURN_THROWS();
 		}
@@ -4886,18 +4884,12 @@ MBSTRING_API size_t php_mb_stripos(int mode, const char *old_haystack, size_t ol
 			break;
 		}
 
- 		if (offset != 0) {
+ 		if (offset < 0 && !mode) {
  			size_t haystack_char_len = mbfl_strlen(&haystack);
-
- 			if (!mode) {
-				if (offset < 0) {
-					offset += (zend_long)haystack_char_len;
-				}
-				if (offset < 0 || (size_t)offset > haystack_char_len) {
- 					zend_value_error("Offset not contained in string");
- 					n = -1;
- 					break;
- 				}
+ 			offset += (zend_long)haystack_char_len;
+			if (offset < 0) {
+ 				n = -16;
+ 				break;
  			}
 		}