dispatch method

@override T? dispatch(List<int> data)

Implementation

@override
T? dispatch(List<int> data) {
  if (data == null || data.length < 5) {
    logger.warning('packet too small: $data');
    return null;
  }
  if (data[0] != SOF) {
    logger.warning('expected SOF (1st byte) to be $SOF in $data');
    return null;
  }
  var expectedLen = data.length - 2;
  if (data[1] != expectedLen) {
    logger.warning('expected length (2nd byte) to be $expectedLen in $data');
    return null;
  }
  int expectedCrc = 0xFF;
  for (int index = 1; index < data.length - 1; ++index) {
    expectedCrc ^= data[index];
  }
  if (data[data.length - 1] != expectedCrc) {
    logger.warning('expected CRC (last byte) to be $expectedCrc in $data');
    return null;
  }
  return super.dispatch(data);
}