Avoid allocation in zend_enum_get_case_cstr() (php#18239)

Future uses of this internal API are planned, and we can easily avoid an
allocation by factoring out the common code.

Author: ndossche

Zend/zend_enum.c

@@ -610,8 +610,7 @@ ZEND_API void zend_enum_add_case_cstr(zend_class_entry *ce, const char *name, zv
 	zend_string_release(name_str);
 }
 
-ZEND_API zend_object *zend_enum_get_case(zend_class_entry *ce, zend_string *name) {
-	zend_class_constant *c = zend_hash_find_ptr(CE_CONSTANTS_TABLE(ce), name);
+static zend_object *zend_enum_case_from_class_constant(zend_class_constant *c) {
 	ZEND_ASSERT(c && "Must be a valid enum case");
 	ZEND_ASSERT(ZEND_CLASS_CONST_FLAGS(c) & ZEND_CLASS_CONST_IS_CASE);
 
@@ -624,9 +623,12 @@ ZEND_API zend_object *zend_enum_get_case(zend_class_entry *ce, zend_string *name
 	return Z_OBJ(c->value);
 }
 
+ZEND_API zend_object *zend_enum_get_case(zend_class_entry *ce, zend_string *name) {
+	zend_class_constant *c = zend_hash_find_ptr(CE_CONSTANTS_TABLE(ce), name);
+	return zend_enum_case_from_class_constant(c);
+}
+
 ZEND_API zend_object *zend_enum_get_case_cstr(zend_class_entry *ce, const char *name) {
-	zend_string *name_str = zend_string_init(name, strlen(name), 0);
-	zend_object *result = zend_enum_get_case(ce, name_str);
-	zend_string_release(name_str);
-	return result;
+	zend_class_constant *c = zend_hash_str_find_ptr(CE_CONSTANTS_TABLE(ce), name, strlen(name));
+	return zend_enum_case_from_class_constant(c);
 }