Allow null as a default value for length in mb_substr() and mb_strcut()

NEWS

@@ -14,6 +14,10 @@ PHP                                                                        NEWS
   . Bug #62987 (Assigning to ArrayObject[null][something] overrides all 
     undefined variables). (Laruence)
 
+- mbstring:
+  . Allow passing null as a default value to mb_substr() and mb_strcut(). Patch
+    by Alexander Moskaliov via GitHub PR #133. (Lars)
+
 ?? ??? 2012, PHP 5.4.7
 
 - Core:

ext/mbstring/mbstring.c

@@ -2715,9 +2715,10 @@ PHP_FUNCTION(mb_substr)
 	char *str, *encoding;
 	long from, len;
 	int mblen, str_len, encoding_len;
+	zval **z_len = NULL;
 	mbfl_string string, result, *ret;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "sl|ls", &str, &str_len, &from, &len, &encoding, &encoding_len) == FAILURE) {
+	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "sl|Zs", &str, &str_len, &from, &z_len, &encoding, &encoding_len) == FAILURE) {
 		return;
 	}
 
@@ -2736,8 +2737,11 @@ PHP_FUNCTION(mb_substr)
 	string.val = (unsigned char *)str;
 	string.len = str_len;
 
-	if (argc < 3) {
+	if (argc < 3 || Z_TYPE_PP(z_len) == IS_NULL) {
 		len = str_len;
+	} else {
+		convert_to_long_ex(z_len);
+		len = Z_LVAL_PP(z_len);
 	}
 
 	/* measures length */
@@ -2788,13 +2792,14 @@ PHP_FUNCTION(mb_strcut)
 	char *encoding;
 	long from, len;
 	int encoding_len;
+	zval **z_len = NULL;
 	mbfl_string string, result, *ret;
 
 	mbfl_string_init(&string);
 	string.no_language = MBSTRG(language);
 	string.no_encoding = MBSTRG(current_internal_encoding)->no_encoding;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "sl|ls", (char **)&string.val, (int **)&string.len, &from, &len, &encoding, &encoding_len) == FAILURE) {
+	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "sl|Zs", (char **)&string.val, (int **)&string.len, &from, &z_len, &encoding, &encoding_len) == FAILURE) {
 		return;
 	}
 
@@ -2806,8 +2811,11 @@ PHP_FUNCTION(mb_strcut)
 		}
 	}
 
-	if (argc < 3) {
+	if (argc < 3 || Z_TYPE_PP(z_len) == IS_NULL) {
 		len = string.len;
+	} else {
+		convert_to_long_ex(z_len);
+		len = Z_LVAL_PP(z_len);
 	}
 
 	/* if "from" position is negative, count start position from the end

ext/mbstring/tests/mb_str_functions_opt-parameter.phpt

@@ -28,5 +28,3 @@ baz
 baz
 foo
 ==DONE==
---XFAIL--
-mb functions fail to allow null instead of actual value