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<?php declare(strict_types=1); |
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namespace DaveRandom\LibLifxLan\Decoding; |
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use DaveRandom\LibLifxLan\Decoding\Exceptions\DecodingException; |
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use DaveRandom\LibLifxLan\Decoding\Exceptions\InsufficientDataException; |
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use DaveRandom\LibLifxLan\Decoding\Exceptions\InvalidMessagePayloadLengthException; |
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use DaveRandom\LibLifxLan\Header\Header; |
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use DaveRandom\LibLifxLan\Packet; |
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final class PacketDecoder |
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{ |
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private const HEADER_OFFSET = 0; |
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private const MESSAGE_OFFSET = Header::WIRE_SIZE; |
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private $headerDecoder; |
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private $messageDecoder; |
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/** |
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* @param string $buffer |
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* @param int $offset |
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* @param int $length |
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* @return int |
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* @throws InsufficientDataException |
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* @throws InvalidMessagePayloadLengthException |
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*/ |
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private function getValidDataLength(string $buffer, int $offset, ?int $length): int |
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{ |
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$dataLength = $length ?? (\strlen($buffer) - $offset); |
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if ($dataLength < Header::WIRE_SIZE) { |
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throw new InsufficientDataException( |
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"Data length {$dataLength} less than minimum packet size " . Header::WIRE_SIZE |
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); |
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} |
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$statedLength = \unpack('vlength', $buffer, $offset)['length']; |
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if ($statedLength !== $dataLength) { |
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throw new InvalidMessagePayloadLengthException( |
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"Packet length is stated to be {$statedLength} bytes, buffer is {$dataLength} bytes" |
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); |
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} |
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return $statedLength; |
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} |
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public function __construct(HeaderDecoder $headerDecoder = null, MessageDecoder $messageDecoder = null) |
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{ |
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$this->headerDecoder = $headerDecoder ?? new HeaderDecoder; |
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$this->messageDecoder = $messageDecoder ?? new MessageDecoder; |
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} |
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public function getHeaderDecoder(): HeaderDecoder |
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{ |
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return $this->headerDecoder; |
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} |
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public function getMessageDecoder(): MessageDecoder |
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{ |
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return $this->messageDecoder; |
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} |
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/** |
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* @param string $buffer |
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* @param int $offset |
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* @param int|null $length |
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* @return Packet |
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* @throws DecodingException |
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* @throws InsufficientDataException |
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* @throws InvalidMessagePayloadLengthException |
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*/ |
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public function decodePacket(string $buffer, int $offset = 0, int $length = null): Packet |
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{ |
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$dataLength = $this->getValidDataLength($buffer, $offset, $length); |
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$header = $this->headerDecoder->decodeHeader($buffer, $offset + self::HEADER_OFFSET); |
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$payload = $this->messageDecoder->decodeMessage( |
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$header->getProtocolHeader()->getType(), |
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$buffer, |
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$offset + self::MESSAGE_OFFSET, |
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$dataLength - Header::WIRE_SIZE |
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); |
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return new Packet($header, $payload); |
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} |
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} |
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DaveRandom /
LibLifxLan
