RC1 optimisation for strto{lower,upper}

Author: ndossche

Zend/zend_operators.c

@@ -2877,6 +2877,18 @@ ZEND_API char* ZEND_FASTCALL zend_str_toupper_dup_ex(const char *source, size_t
 }
 /* }}} */
 
+static zend_string* ZEND_FASTCALL zend_string_alloc_or_partial_dup(zend_string *str, bool persistent, const unsigned char *p)
+{
+	if (persistent || !zend_may_modify_string_in_place(str)) {
+		zend_string *res = zend_string_alloc(ZSTR_LEN(str), persistent);
+		memcpy(ZSTR_VAL(res), ZSTR_VAL(str), p - (unsigned char *) ZSTR_VAL(str));
+		return res;
+	} else {
+		zend_string_forget_hash_val(str);
+		return str;
+	}
+}
+
 ZEND_API zend_string* ZEND_FASTCALL zend_string_tolower_ex(zend_string *str, bool persistent) /* {{{ */
 {
 	size_t length = ZSTR_LEN(str);
@@ -2888,8 +2900,7 @@ ZEND_API zend_string* ZEND_FASTCALL zend_string_tolower_ex(zend_string *str, boo
 	while (p + BLOCKCONV_STRIDE <= end) {
 		BLOCKCONV_LOAD(p);
 		if (BLOCKCONV_FOUND()) {
-			zend_string *res = zend_string_alloc(length, persistent);
-			memcpy(ZSTR_VAL(res), ZSTR_VAL(str), p - (unsigned char *) ZSTR_VAL(str));
+			zend_string *res = zend_string_alloc_or_partial_dup(str, persistent, p);
 			unsigned char *q = (unsigned char*) ZSTR_VAL(res) + (p - (unsigned char*) ZSTR_VAL(str));
 
 			/* Lowercase the chunk we already compared. */
@@ -2909,8 +2920,7 @@ ZEND_API zend_string* ZEND_FASTCALL zend_string_tolower_ex(zend_string *str, boo
 
 	while (p < end) {
 		if (*p != zend_tolower_ascii(*p)) {
-			zend_string *res = zend_string_alloc(length, persistent);
-			memcpy(ZSTR_VAL(res), ZSTR_VAL(str), p - (unsigned char*) ZSTR_VAL(str));
+			zend_string *res = zend_string_alloc_or_partial_dup(str, persistent, p);
 
 			unsigned char *q = (unsigned char*) ZSTR_VAL(res) + (p - (unsigned char*) ZSTR_VAL(str));
 			while (p < end) {
@@ -2937,8 +2947,7 @@ ZEND_API zend_string* ZEND_FASTCALL zend_string_toupper_ex(zend_string *str, boo
 	while (p + BLOCKCONV_STRIDE <= end) {
 		BLOCKCONV_LOAD(p);
 		if (BLOCKCONV_FOUND()) {
-			zend_string *res = zend_string_alloc(length, persistent);
-			memcpy(ZSTR_VAL(res), ZSTR_VAL(str), p - (unsigned char *) ZSTR_VAL(str));
+			zend_string *res = zend_string_alloc_or_partial_dup(str, persistent, p);
 			unsigned char *q = (unsigned char *) ZSTR_VAL(res) + (p - (unsigned char *) ZSTR_VAL(str));
 
 			/* Uppercase the chunk we already compared. */
@@ -2958,8 +2967,7 @@ ZEND_API zend_string* ZEND_FASTCALL zend_string_toupper_ex(zend_string *str, boo
 
 	while (p < end) {
 		if (*p != zend_toupper_ascii(*p)) {
-			zend_string *res = zend_string_alloc(length, persistent);
-			memcpy(ZSTR_VAL(res), ZSTR_VAL(str), p - (unsigned char*) ZSTR_VAL(str));
+			zend_string *res = zend_string_alloc_or_partial_dup(str, persistent, p);
 
 			unsigned char *q = (unsigned char *) ZSTR_VAL(res) + (p - (unsigned char *) ZSTR_VAL(str));
 			while (p < end) {