Symfony\Component\Templating\PhpEngine::convertEncoding PHP Method

    public function convertEncoding($string, $to, $from)
    {
        if (function_exists('iconv')) {
            return iconv($from, $to, $string);
        } elseif (function_exists('mb_convert_encoding')) {
            return mb_convert_encoding($string, $to, $from);
        }

        throw new \RuntimeException('No suitable convert encoding function (use UTF-8 as your encoding or install the iconv or mbstring extension).');
    }