/// <summary>
/// Tries to create a packet from the header information.
/// </summary>
/// <param name="data">The data.</param>
/// <param name="timeStamp">The time stamp.</param>
/// <param name="packet">The packet.</param>
/// <returns></returns>
internal static bool TryBuild(DJTapRecieveData data, DateTime timeStamp, out DJTapPacket packet)
{
DJTapHeader header = new DJTapHeader(MessageTypes.None);
packet = header;
try
{
//We have read all the data.
if (data.EndOfData())
{
data.Reset();
return(false);
}
//Check we have enough data to construct the header.
if (data.Length - data.ReadPosition < DJTapHeader.PacketSize)
{
return(false);
}
//Read the packet header.
header.ReadData(data.GetReader());
//Ensure the header packet is valid
if (!header.IsValid())
{
//Purge data as it is probably corrupted.
data.Reset(); //Reset position to start so we dump the data.
return(false);
}
//Read the sub packet
switch (header.ContentType)
{
case MessageTypes.GWOffer:
packet = new GWOffer();
break;
case MessageTypes.Timecode:
packet = new Timecode();
break;
default:
return(false);
}
packet.TimeStamp = timeStamp;
packet.ReadData(data.GetReader());
}
catch (EndOfStreamException)
{
return(false);
}
return(packet != null);
}
/// <summary>
/// Starts recieving data on an open socket.
/// </summary>
/// <param name="socket">The socket to recieve data on.</param>
/// <param name="port">The port to recieve data on.</param>
protected void StartRecieve(Socket socket, int port)
{
try
{
EndPoint localPort = new IPEndPoint(IPAddress.Any, port);
DJTapRecieveData recieveState = new DJTapRecieveData()
{
Socket = socket,
Port = port
};
recieveState.SetLength(1500);
socket.BeginReceiveFrom(recieveState.GetBuffer(), 0, (int)recieveState.Length, SocketFlags.None, ref localPort, new AsyncCallback(OnRecieve), recieveState);
}
catch (Exception ex)
{
OnUnhandledException(new ApplicationException("An error ocurred while trying to start recieving ArtNet.", ex));
}
}
/// <summary>
/// Called when when new data is recieved on a socket.
/// </summary>
/// <param name="state">The recieve data for this transaction.</param>
private void OnRecieve(IAsyncResult state)
{
EndPoint remoteEndPoint = new IPEndPoint(IPAddress.Any, 0);
if (PortOpen)
{
DJTapRecieveData recieveState = (DJTapRecieveData)(state.AsyncState);
if (recieveState != null)
{
try
{
recieveState.SetLength((recieveState.Length - recieveState.ReadNibble) + recieveState.Socket.EndReceiveFrom(state, ref remoteEndPoint));
//Protect against UDP loopback where we recieve our own packets.
if (LocalEndPoint != remoteEndPoint && recieveState.Valid)
{
LastPacket = DateTime.UtcNow;
DJTapPacket newPacket;
while (DJTapPacketBuilder.TryBuild(recieveState, (DateTime)LastPacket, out newPacket))
{
recieveState.ReadPosition = (int)recieveState.Position;
//Packet has been read successfully.
if (NewPacket != null)
{
NewPacket(this, new NewPacketEventArgs <DJTapPacket>((IPEndPoint)remoteEndPoint, newPacket));
}
}
}
}
catch (Exception ex)
{
OnUnhandledException(ex);
}
finally
{
//Attempt to recieve another packet.
StartRecieve(recieveState.Socket, recieveState.Port);
}
}
}
}
