private function computeAccess($and, $xor, $bit)
    {
        $xorBit = \databox_status::bitIsSet($xor, $bit);
        $andBit = \databox_status::bitIsSet($and, $bit);

        if (!$xorBit && !$andBit) {
            return self::FLAG_ALLOW_BOTH;
        }

        if ($xorBit && $andBit) {
            return self::FLAG_SET_ONLY;
        }

        return self::FLAG_UNSET_ONLY;
    }