Added php_ob_handler_used to check if a specific output handler is used

in c.

main/output.c

@@ -403,6 +403,40 @@ PHP_FUNCTION(ob_list_handlers)
 }
 /* }}} */
 
+/* {{{ php_ob_used_each
+   Sets handler_name to NULL is found
+ */
+static int php_ob_handler_used_each(php_ob_buffer *ob_buffer, char **handler_name) 
+{
+	if ((!strcmp(ob_buffer->handler_name, "zlib output compression") && ob_buffer->internal_output_handler && !strcmp("ob_gzhandler", *handler_name))
+	  || !strcmp(ob_buffer->handler_name, *handler_name))
+	{
+		*handler_name = NULL;
+		return 1;
+	}
+	return 0;
+}
+/* }}} */
+
+/* {{{ php_ob_used
+   returns 1 if given handler_name is used as output_handler
+ */
+PHPAPI int php_ob_handler_used(char *handler_name TSRMLS_DC)
+{
+	char *tmp = handler_name;
+
+	if (OG(ob_nesting_level)) {
+		if (!strcmp(OG(active_ob_buffer).handler_name, handler_name)) {
+			return 1;
+		}
+		if (OG(ob_nesting_level)>1) {
+			zend_stack_apply_with_argument(&OG(ob_buffers), ZEND_STACK_APPLY_BOTTOMUP, (int (*)(void *element, void *)) php_ob_handler_used_each, &tmp);
+		}
+	}
+	return tmp ? 0 : 1;
+}
+/* }}} */
+
 /* {{{ php_ob_append
  */
 static void php_ob_append(const char *text, uint text_length TSRMLS_DC)

main/php_output.h

@@ -39,6 +39,7 @@ PHPAPI void php_end_implicit_flush(TSRMLS_D);
 PHPAPI char *php_get_output_start_filename(TSRMLS_D);
 PHPAPI int php_get_output_start_lineno(TSRMLS_D);
 PHPAPI void php_ob_set_internal_handler(php_output_handler_func_t internal_output_handler, uint buffer_size, char *handler_name, zend_bool erase TSRMLS_DC);
+PHPAPI int php_ob_handler_used(char *handler_name TSRMLS_DC);
 
 PHP_FUNCTION(ob_start);
 PHP_FUNCTION(ob_flush);