SerialMonitor.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.IO.Ports;
using System.Windows.Threading;

namespace NintendoSpy
{
    public delegate void PacketEventHandler (object sender, byte[] packet);

    public class SerialMonitor
    {
        const int BAUD_RATE = 115200;
        const int TIMER_MS  = 30;

        public event PacketEventHandler PacketReceived;
        public event EventHandler Disconnected;

        SerialPort _datPort;
        List <byte> _localBuffer;

        DispatcherTimer _timer;

        public SerialMonitor (string portName)
        {
            _localBuffer = new List <byte> ();
            _datPort = new SerialPort (portName, BAUD_RATE);
            _datPort.Handshake = Handshake.RequestToSend;
            _datPort.DtrEnable = true;
        }

        public void Start ()
        {
            if (_timer != null) return;

            _localBuffer.Clear ();
            _datPort.Open ();

            _timer = new DispatcherTimer ();
            _timer.Interval = TimeSpan.FromMilliseconds (TIMER_MS); 
            _timer.Tick += tick;
            _timer.Start ();
        }

        public void Stop ()
        {
            if (_datPort != null) {
                try { // If the device has been unplugged, Close will throw an IOException.  This is fine, we'll just keep cleaning up.
                    _datPort.Close ();
                }
                catch (IOException) {}
                _datPort = null;
            }
            if (_timer != null) {
                _timer.Stop ();
                _timer = null;
            }
        }

        void tick (object sender, EventArgs e)
        {
            if (_datPort == null || !_datPort.IsOpen || PacketReceived == null) return;

            // Try to read some data from the COM port and append it to our localBuffer.
            // If there's an IOException then the device has been disconnected.
            try {
                int readCount = _datPort.BytesToRead;
                if (readCount < 1) return;
                byte[] readBuffer = new byte [readCount];
                _datPort.Read (readBuffer, 0, readCount);
                _datPort.DiscardInBuffer ();
                _localBuffer.AddRange (readBuffer);
            }
            catch (IOException) {
                Stop ();
                if (Disconnected != null) Disconnected (this, EventArgs.Empty);
                return;
            }

            // Try and find 2 splitting characters in our buffer.
            int lastSplitIndex = _localBuffer.LastIndexOf (0x0A);
            if (lastSplitIndex <= 1) return;
            int sndLastSplitIndex = _localBuffer.LastIndexOf (0x0A, lastSplitIndex - 1);
            if (lastSplitIndex == -1) return;

            // Grab the latest packet out of the buffer and fire it off to the receive event listeners.
            int packetStart = sndLastSplitIndex + 1;
            int packetSize  = lastSplitIndex - packetStart;
            PacketReceived (this, _localBuffer.GetRange (packetStart, packetSize).ToArray ());

            // Clear our buffer up until the last split character.
            _localBuffer.RemoveRange (0, lastSplitIndex);
        }
    }
}