/**
* Decode the header section of the message
*
* @param \LibDNS\Decoder\DecodingContext $decodingContext
* @param \LibDNS\Messages\Message $message
* @throws \UnexpectedValueException When the header section is invalid
*/
private function decodeHeader(DecodingContext $decodingContext, Message $message)
{
$header = unpack('nid/nmeta/nqd/nan/nns/nar', $this->readDataFromPacket($decodingContext->getPacket(), 12));
if (!$header) {
throw new \UnexpectedValueException('Decode error: Header unpack failed');
}
$message->setID($header['id']);
$message->setType(($header['meta'] & 0b1000000000000000) >> 15);
$message->setOpCode(($header['meta'] & 0b111100000000000) >> 11);
$message->isAuthoritative(($header['meta'] & 0b10000000000) >> 10);
$message->isTruncated(($header['meta'] & 0b1000000000) >> 9);
$message->isRecursionDesired(($header['meta'] & 0b100000000) >> 8);
$message->isRecursionAvailable(($header['meta'] & 0b10000000) >> 7);
$message->setResponseCode($header['meta'] & 0b1111);
$decodingContext->setExpectedQuestionRecords($header['qd']);
$decodingContext->setExpectedAnswerRecords($header['an']);
$decodingContext->setExpectedAuthorityRecords($header['ns']);
$decodingContext->setExpectedAdditionalRecords($header['ar']);
}
