protected function matchUserAgent($regex)
    {
        // only match if useragent begins with given regex or there is no letter before it
        $regex = '/(?:^|[^A-Z0-9\-_]|[^A-Z0-9\-]_|sprd-)(?:' . str_replace('/', '\/', $regex) . ')/i';

        if (preg_match($regex, $this->userAgent, $matches)) {
            return $matches;
        }

        return false;
    }