protected function _filePutContents($file, $string)
    {
        $result = false;
        $f = @fopen($file, 'ab+');
        if ($f) {
            if ($this->_options['file_locking']) @flock($f, LOCK_EX);
            fseek($f, 0);
            ftruncate($f, 0);
            $tmp = @fwrite($f, $string);
            if (!($tmp === FALSE)) {
                $result = true;
            }
            @fclose($f);
        }
        @chmod($file, $this->_options['cache_file_umask']);
        return $result;
    }