readFrom method

void readFrom(MqttByteBuffer headerStream)

Creates a new MqttHeader based on a list of bytes.

Implementation

void readFrom(MqttByteBuffer headerStream) {
  if (headerStream.length < 2) {
    headerStream.reset();
    throw InvalidHeaderException(
        'The supplied header is invalid. Header must be at '
        'least 2 bytes long.');
  }
  final firstHeaderByte = headerStream.readByte();
  // Pull out the first byte
  retain = (firstHeaderByte & 1) == 1;
  qos = MqttUtilities.getQosLevel((firstHeaderByte & 6) >> 1);
  duplicate = ((firstHeaderByte & 8) >> 3) == 1;
  messageType = MqttMessageType.values[((firstHeaderByte & 240) >> 4)];

  // Decode the remaining bytes as the remaining/payload size, input param is the 2nd to last byte of the header byte list
  try {
    _messageSize = readRemainingLength(headerStream);
  } on Exception {
    throw InvalidHeaderException(
        'The header being processed contained an invalid size byte pattern. '
        'Message size must take a most 4 bytes, and the last byte '
        'must have bit 8 set to 0.');
  } on Error {
    throw InvalidHeaderException(
        'The header being processed contained an invalid size byte pattern. '
        'Message size must take a most 4 bytes, and the last byte '
        'must have bit 8 set to 0.');
  }
}