public static Packet ReadPacket(Stream stream)
{
var headerBuffer = new byte[1];
var bytesRead = stream.Read(headerBuffer, 0, 1);
if (bytesRead == 0)
{
return null;
}
var headerVal = (byte)(headerBuffer[0] >> 4);
var payloadLength = (headerBuffer[0] & 0x0F);
var packet = new Packet((PacketHeaderType)Enum.Parse(typeof(PacketHeaderType), headerVal.ToString()));
var bytesRemaining = payloadLength;
var offset = 0;
if (payloadLength > 0)
{
var payloadBytes = new byte[payloadLength];
do
{
bytesRead = stream.Read(payloadBytes, offset, bytesRemaining);
if (bytesRead == 0)
{
throw new XpressNetProtocolViolationException("Unexpected end of stream");
}
bytesRemaining -= bytesRead;
offset += bytesRead;
} while (bytesRemaining > 0);
packet.Payload.AddRange(payloadBytes);
// .ToString() is relatively expensive, so only do it if we're logging
if (XpressNetConstants.XpressNetTraceSource.Switch.ShouldTrace(TraceEventType.Verbose))
{
XpressNetConstants.XpressNetTraceSource.TraceEvent(TraceEventType.Verbose, 0, "Received Packet: {0}", packet.ToString());
}
if (Debugger.IsAttached)
{
Console.Out.WriteLineAsync(string.Format("Received Packet: {0}", packet));
}
}
//check the xor matches
var xorByte = new byte[1];
stream.Read(xorByte, 0, 1);
if (xorByte[0] != packet.GetXoredByte())
throw new XpressNetProtocolViolationException("Packet checksum is invalid");
PacketReceived(packet, stream);
return packet;
}
protected override bool ValidResponse(Packet packet)
{
if (packet.Header == PacketHeaderType.LocomotiveFunction) //TODO: unit test to check this works
{
ResponseData = new LocoInfoResp_NormalResp(); //TODO: if the loco is in a dh or mu it may return a different resp?! (it is probably better to modify the response to make it generic!
return true;
}
else
{
return false;
}
}
protected override bool ValidResponse(Packet packet)
{
if (packet.Header == PacketHeaderType.LocomotiveFunction && (packet.Payload[0] > 0x80 && packet.Payload[0] < 0x89)) //TODO: unit test to check this works
{
ResponseData = new SetMultiUnitOrDoubleHeaderErrorResp();
return true;
}
else
{
return false;
}
}
//TODO: check that this actually happens as the specification is a little ambigous
protected override bool ValidResponse(Packet packet)
{
if (packet.Header == PacketHeaderType.CommandStationOperationResponse &&
packet.Payload[0] == Convert.ToByte(PacketIdentifier.CommandStationOperationResponse.ServiceModeEntryBroadcast))
{
ResponseData = new GeneralResponse();
return true;
}
else
{
return false;
}
}
protected override bool ValidResponse(Packet packet)
{
if (packet.Header == PacketHeaderType.CommandStationOperationResponse &&
packet.Payload[0] == Convert.ToByte(PacketIdentifier.CommandStationOperationResponse.CmdStnSoftwareVersion))
{
ResponseData = new CmdStnSoftwareVersionResp();
return true;
}
else
{
return false;
}
}
protected override bool ValidResponse(Packet packet)
{
if (packet.Header == PacketHeaderType.LocomotiveFunction &&
(packet.Payload[0] > Convert.ToByte(PacketIdentifier.LocomotiveFunctionResponse.MultiUnitOrDoubleHeaderError) &&
packet.Payload[0] < (Convert.ToByte(PacketIdentifier.LocomotiveFunctionResponse.MultiUnitOrDoubleHeaderError) + 9))) //TODO: unit test to check this works
{
ResponseData = new SetMultiUnitOrDoubleHeaderErrorResp();
return true;
}
else
{
return false;
}
}
protected override bool ValidResponse(Packet packet)
{
if (packet.Header == PacketHeaderType.CommandStationOperationResponse &&
packet.Payload[0] == Convert.ToByte(PacketIdentifier.CommandStationOperationResponse.ServiceModeForRegisterAndPagedMode))
{
ResponseData = new ServiceModeProgrammingResultsResp();
return true;
}
else if (packet.Header == PacketHeaderType.CommandStationOperationResponse &&
packet.Payload[0] == Convert.ToByte(PacketIdentifier.CommandStationOperationResponse.ServiceModeForDirectCvMode))
{
ResponseData = new ServiceModeProgrammingResultsResp();
return true;
}
else if (packet.Header == PacketHeaderType.CommandStationOperationResponse &&
packet.Payload[0] == Convert.ToByte(PacketIdentifier.CommandStationOperationResponse.ProgrammingInfoDataByteNotFound))
{
ResponseData = new GeneralResponse();
return true;
}
else if (packet.Header == PacketHeaderType.CommandStationOperationResponse &&
packet.Payload[0] == Convert.ToByte(PacketIdentifier.CommandStationOperationResponse.ProgrammingInfoShortCircuit))
{
ResponseData = new GeneralResponse();
return true;
}
else if (packet.Header == PacketHeaderType.CommandStationOperationResponse &&
packet.Payload[0] == Convert.ToByte(PacketIdentifier.CommandStationOperationResponse.ProgrammingInfoCommandStationBusy))
{
ResponseData = new GeneralResponse();
return true;
}
else if (packet.Header == PacketHeaderType.CommandStationOperationResponse &&
packet.Payload[0] == Convert.ToByte(PacketIdentifier.CommandStationOperationResponse.ProgrammingInfoCommandStationReady))
{
ResponseData = new GeneralResponse();
return true;
}
else if (packet.Header == PacketHeaderType.CommandStationOperationResponse &&
packet.Payload[0] == Convert.ToByte(PacketIdentifier.CommandStationOperationResponse.InstructionUnsupported))
{
ResponseData = new GeneralResponse();
return true;
}
else
{
return false;
}
}
internal async static void PacketReceived(Packet packet, Stream stream)
{
//Handle Direct return messages : it is possible this should be placed in the packet class!
if (packet.Header == PacketHeaderType.CommandStationOperationResponse && packet.Payload[0] == Convert.ToByte(PacketIdentifier.CommandStationOperationResponse.TransferErrors))
{
var ackResp = new AckRespMessage();
//if (XpressNetConstants.UseAsyncWrite)
//{
// //ackResp.WriteAsync(stream);
//}
//else
//{
await ackResp.WriteAsync(stream);
//}
}
//Handle Broadcast Messages
if (packet.Header == PacketHeaderType.EmergencyStopAll)
{
var bmr = new BroadcastMessageReceivedEventArgs
{
ResponseType = BroadcastType.EmergencyStop,
ReceivedTime = DateTime.Now
};
OnBroadcastMessageReceived(bmr);
}
else if (packet.Header == PacketHeaderType.CommandStationOperationResponse && packet.Payload[0] == Convert.ToByte(PacketIdentifier.CommandStationOperationResponse.NormalOperationsResumedBroadcast))
{
var bmr = new BroadcastMessageReceivedEventArgs
{
ResponseType = BroadcastType.NormalOperationResumed,
ReceivedTime = DateTime.Now
};
OnBroadcastMessageReceived(bmr);
}
else if (packet.Header == PacketHeaderType.CommandStationOperationResponse && packet.Payload[0] == Convert.ToByte(PacketIdentifier.CommandStationOperationResponse.TrackPowerOffBroadcast))
{
var bmr = new BroadcastMessageReceivedEventArgs
{
ResponseType = BroadcastType.TrackPowerOff,
ReceivedTime = DateTime.Now
};
OnBroadcastMessageReceived(bmr);
}
else if (packet.Header == PacketHeaderType.CommandStationOperationResponse && packet.Payload[0] == Convert.ToByte(PacketIdentifier.CommandStationOperationResponse.ServiceModeEntryBroadcast))
{
var bmr = new BroadcastMessageReceivedEventArgs
{
ResponseType = BroadcastType.ServiceModeEntry,
ReceivedTime = DateTime.Now
};
OnBroadcastMessageReceived(bmr);
}
else if (packet.Header == PacketHeaderType.AccessoryDecoderInformation)
{
var bmr = new BroadcastMessageReceivedEventArgs
{
ResponseType = BroadcastType.AccessoryFeedback,
ReceivedTime = DateTime.Now
};
//bmr.Response =
OnBroadcastMessageReceived(bmr);
}
//else if (packet.Header == PacketHeaderType.LocomotiveFunction && packet.Payload[0] == Convert.ToByte(PacketIdentifier.LocomotiveFunctionResponses.LocomotiveOperatedByAnotherDevice))
//{
//BroadcastMessageReceivedEventArgs bmr = new BroadcastMessageReceivedEventArgs();
//bmr.ResponseType = BroadcastType.LocomotiveOperatedByAnotherDevice;
//bmr.Response =
//OnBroadcastMessageReceived(bmr);
//}
//else if (packet.Header == PacketHeaderType.LocomotiveFunction && packet.Payload[0] == Convert.ToByte(PacketIdentifier.LocomotiveFunctionResponses.LocomotiveDoubleHeaderOccupied))
//{
//BroadcastMessageReceivedEventArgs bmr = new BroadcastMessageReceivedEventArgs();
//bmr.ResponseType = BroadcastType.DoubleHeaderOccupied;
//bmr.Response =
//OnBroadcastMessageReceived(bmr);
//}
//else //we may wish to send the broadcasts on anyway so this else may have to be removed!!
//{
var pump = new PacketRouter();
pump.DisseminatePacket(packet);
//}
}
