public static function encode($string)
    {
        return is_null($string) ? self::NULL : strtr($string, self::$encodeMap);
    }
public static function encode($string)
    {
        return is_null($string) ? self::NULL : strtr($string, self::$encodeMap);
    }
public static function encode ( $ string ) { return is_null ( $ string ) ? self :: NULL : strtr ( $ string , self :: $ encodeMap ) ; }
Encode string for sending to server

@param $string
@return string
Encode string for sending to server