private static function setStr($str)
    {
        self::$str = $str;
        self::$curI = 0;
        self::$stats = array(
            'bytesOther' => 0,
            'bytesSpecial' => 0,        // special UTF-8
            'bytesUtf8' => 0,           // includes ASCII
            'strLen' => \strlen($str),
        );
    }