Nefarius.Peripherals.SerialPort/PInvokeSerialPort/SerialPort.cs

using System;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading;
using PInvokeSerialPort.Win32PInvoke;

namespace PInvokeSerialPort
{
    /// <summary>
    /// PInvokeSerialPort main class.
    /// Borrowed from http://msdn.microsoft.com/en-us/magazine/cc301786.aspx ;)
    /// </summary>
    public class SerialPort : IDisposable
    {
        private IntPtr _hPort;
        private IntPtr _ptrUwo = IntPtr.Zero;
        private Thread _rxThread;
        private bool _online;
        private bool _auto;
        private bool _checkSends = true;
        private Exception _rxException;
        private bool _rxExceptionReported;
        private int _writeCount;
        private readonly ManualResetEvent _writeEvent = new ManualResetEvent(false);
        private int _stateRts = 2;
        private int _stateDtr = 2;
        private int _stateBrk = 2;

        /// <summary>
        /// Class contructor
        /// </summary>
        public SerialPort(string portName)
        {
            PortName = portName;
        }

        /// <summary>
        /// Class contructor
        /// </summary>
        public SerialPort(string portName, int baudRate)
        {
            PortName = portName;
            BaudRate = baudRate;
        }

        /// <summary>
        /// Opens the com port and configures it with the required settings
        /// </summary>
        /// <returns>false if the port could not be opened</returns>
        public bool Open()
        {
            var portDcb = new DCB();
            var commTimeouts = new COMMTIMEOUTS();
            var wo = new OVERLAPPED();

            if (_online) return false;

            _hPort = Win32Com.CreateFile(PortName, Win32Com.GENERIC_READ | Win32Com.GENERIC_WRITE, 0, IntPtr.Zero,
                Win32Com.OPEN_EXISTING, Win32Com.FILE_FLAG_OVERLAPPED, IntPtr.Zero);
            if (_hPort == (IntPtr)Win32Com.INVALID_HANDLE_VALUE)
            {
                if (Marshal.GetLastWin32Error() == Win32Com.ERROR_ACCESS_DENIED)
                {
                    return false;
                }
                throw new CommPortException("Port Open Failure");
            }

            _online = true;

            commTimeouts.ReadIntervalTimeout = 0;
            commTimeouts.ReadTotalTimeoutConstant = 0;
            commTimeouts.ReadTotalTimeoutMultiplier = 0;
            commTimeouts.WriteTotalTimeoutConstant = SendTimeoutConstant;
            commTimeouts.WriteTotalTimeoutMultiplier = SendTimeoutMultiplier;
            portDcb.Init(((Parity == Parity.Odd) || (Parity == Parity.Even)), TxFlowCts, TxFlowDsr,
                (int)UseDtr, RxGateDsr, !TxWhenRxXoff, TxFlowX, RxFlowX, (int)UseRts);
            portDcb.BaudRate = BaudRate;
            portDcb.ByteSize = (byte)DataBits;
            portDcb.Parity = (byte)Parity;
            portDcb.StopBits = (byte)StopBits;
            portDcb.XoffChar = (byte)XoffChar;
            portDcb.XonChar = (byte)XonChar;
            portDcb.XoffLim = (short)RxHighWater;
            portDcb.XonLim = (short)RxLowWater;
            if ((RxQueue != 0) || (TxQueue != 0))
                if (!Win32Com.SetupComm(_hPort, (uint)RxQueue, (uint)TxQueue)) ThrowException("Bad queue settings");
            if (!Win32Com.SetCommState(_hPort, ref portDcb)) ThrowException("Bad com settings");
            if (!Win32Com.SetCommTimeouts(_hPort, ref commTimeouts)) ThrowException("Bad timeout settings");

            _stateBrk = 0;
            if (UseDtr == HsOutput.None) _stateDtr = 0;
            if (UseDtr == HsOutput.Online) _stateDtr = 1;
            if (UseRts == HsOutput.None) _stateRts = 0;
            if (UseRts == HsOutput.Online) _stateRts = 1;

            _checkSends = CheckAllSends;
            wo.Offset = 0;
            wo.OffsetHigh = 0;
            wo.hEvent = _checkSends ? _writeEvent.Handle : IntPtr.Zero;
            _ptrUwo = Marshal.AllocHGlobal(Marshal.SizeOf(wo));
            Marshal.StructureToPtr(wo, _ptrUwo, true);
            _writeCount = 0;

            _rxException = null;
            _rxExceptionReported = false;
            _rxThread = new Thread(ReceiveThread)
                            {
                                Name = "CommBaseRx",
                                Priority = ThreadPriority.AboveNormal
                            };
            //If not set to true, my application process will not exit completely after UI closed
            _rxThread.IsBackground = true;
            _rxThread.Start();
            Thread.Sleep(1); //Give rx thread time to start. By documentation, 0 should work, but it does not!

            _auto = false;
            if (AfterOpen())
            {
                _auto = AutoReopen;
                return true;
            }
            Close();
            return false;
        }

        /// <summary>
        /// Closes the com port.
        /// </summary>
        public void Close()
        {
            if (_online)
            {
                _auto = false;
                BeforeClose(false);
                InternalClose();
                _rxException = null;
            }
        }

        private void InternalClose()
        {
            Win32Com.CancelIo(_hPort);
            if (_rxThread != null)
            {
                _rxThread.Abort();
                _rxThread = null;
            }
            Win32Com.CloseHandle(_hPort);
            if (_ptrUwo != IntPtr.Zero) Marshal.FreeHGlobal(_ptrUwo);
            _stateRts = 2;
            _stateDtr = 2;
            _stateBrk = 2;
            _online = false;
        }

        /// <summary>
        /// For IDisposable
        /// </summary>
        public void Dispose() { Close(); }

        /// <summary>
        /// Destructor (just in case)
        /// </summary>
        ~SerialPort() { Close(); }

        /// <summary>
        /// True if online.
        /// </summary>
        public bool Online { get { return _online && CheckOnline(); } }

        /// <summary>
        /// Block until all bytes in the queue have been transmitted.
        /// </summary>
        public void Flush()
        {
            CheckOnline();
            CheckResult();
        }

        /// <summary>
        /// Use this to throw exceptions in derived classes. Correctly handles threading issues
        /// and closes the port if necessary.
        /// </summary>
        /// <param name="reason">Description of fault</param>
        protected void ThrowException(string reason)
        {
            if (Thread.CurrentThread == _rxThread)
            {
                throw new CommPortException(reason);
            }
            if (_online)
            {
                BeforeClose(true);
                InternalClose();
            }
            if (_rxException == null)
            {
                throw new CommPortException(reason);
            }
            throw new CommPortException(_rxException);
        }

        /// <summary>
        /// Queues bytes for transmission. 
        /// </summary>
        /// <param name="toSend">Array of bytes to be sent</param>
        public void Write(byte[] toSend)
        {
            uint sent;
            CheckOnline();
            CheckResult();
            _writeCount = toSend.GetLength(0);
            if (Win32Com.WriteFile(_hPort, toSend, (uint)_writeCount, out sent, _ptrUwo))
            {
                _writeCount -= (int)sent;
            }
            else
            {
                if (Marshal.GetLastWin32Error() != Win32Com.ERROR_IO_PENDING) ThrowException("Unexpected failure");
            }
        }

        /// <summary>
        /// Queues string for transmission. 
        /// </summary>
        /// <param name="toSend">Array of bytes to be sent</param>
        public void Write(string toSend)
        {
            Write(new ASCIIEncoding().GetBytes(toSend));
        }

        /// <summary>
        /// Queues a single byte for transmission.
        /// </summary>
        /// <param name="toSend">Byte to be sent</param>
        public void Write(byte toSend)
        {
            var b = new byte[1];
            b[0] = toSend;
            Write(b);
        }

        /// <summary>
        /// Queues a single char for transmission.
        /// </summary>
        /// <param name="toSend">Byte to be sent</param>
        public void Write(char toSend)
        {
            Write(toSend.ToString());
        }

        /// <summary>
        /// Queues string with a new line ("\r\n") for transmission. 
        /// </summary>
        /// <param name="toSend">Array of bytes to be sent</param>
        public void WriteLine(string toSend)
        {
            Write(new ASCIIEncoding().GetBytes(toSend + Environment.NewLine));
        }

        private void CheckResult()
        {
            if (_writeCount <= 0) return;
            uint sent;
            if (Win32Com.GetOverlappedResult(_hPort, _ptrUwo, out sent, _checkSends))
            {
                _writeCount -= (int)sent;
                if (_writeCount != 0) ThrowException("Send Timeout");
            }
            else
            {
                if (Marshal.GetLastWin32Error() != Win32Com.ERROR_IO_PENDING) ThrowException("Unexpected failure");
            }
        }

        /// <summary>
        /// Sends a protocol byte immediately ahead of any queued bytes.
        /// </summary>
        /// <param name="tosend">Byte to send</param>
        /// <returns>False if an immediate byte is already scheduled and not yet sent</returns>
        public void SendImmediate(byte tosend)
        {
            CheckOnline();
            if (!Win32Com.TransmitCommChar(_hPort, tosend)) ThrowException("Transmission failure");
        }

        /// <summary>
        /// Delay processing.
        /// </summary>
        /// <param name="milliseconds">Milliseconds to delay by</param>
        protected void Sleep(int milliseconds)
        {
            Thread.Sleep(milliseconds);
        }

        /// <summary>
        /// Gets the status of the modem control input signals.
        /// </summary>
        /// <returns>Modem status object</returns>
        protected ModemStatus GetModemStatus()
        {
            uint f;

            CheckOnline();
            if (!Win32Com.GetCommModemStatus(_hPort, out f)) ThrowException("Unexpected failure");
            return new ModemStatus(f);
        }


        /// <summary>
        /// Get the status of the queues
        /// </summary>
        /// <returns>Queue status object</returns>
        protected QueueStatus GetQueueStatus()
        {
            COMSTAT cs;
            COMMPROP cp;
            uint er;

            CheckOnline();
            if (!Win32Com.ClearCommError(_hPort, out er, out cs)) ThrowException("Unexpected failure");
            if (!Win32Com.GetCommProperties(_hPort, out cp)) ThrowException("Unexpected failure");
            return new QueueStatus(cs.Flags, cs.cbInQue, cs.cbOutQue, cp.dwCurrentRxQueue, cp.dwCurrentTxQueue);
        }

        /// <summary>
        /// True if the RTS pin is controllable via the RTS property
        /// </summary>
        protected bool RtSavailable { get { return (_stateRts < 2); } }

        /// <summary>
        /// Set the state of the RTS modem control output
        /// </summary>
        protected bool Rts
        {
            set
            {
                if (_stateRts > 1) return;
                CheckOnline();
                if (value)
                {
                    if (Win32Com.EscapeCommFunction(_hPort, Win32Com.SETRTS))
                        _stateRts = 1;
                    else
                        ThrowException("Unexpected Failure");
                }
                else
                {
                    if (Win32Com.EscapeCommFunction(_hPort, Win32Com.CLRRTS))
                        _stateRts = 1;
                    else
                        ThrowException("Unexpected Failure");
                }
            }
            get
            {
                return (_stateRts == 1);
            }
        }

        /// <summary>
        /// True if the DTR pin is controllable via the DTR property
        /// </summary>
        protected bool DtrAvailable { get { return (_stateDtr < 2); } }

        /// <summary>
        /// The state of the DTR modem control output
        /// </summary>
        protected bool Dtr
        {
            set
            {
                if (_stateDtr > 1) return;
                CheckOnline();
                if (value)
                {
                    if (Win32Com.EscapeCommFunction(_hPort, Win32Com.SETDTR))
                        _stateDtr = 1;
                    else
                        ThrowException("Unexpected Failure");
                }
                else
                {
                    if (Win32Com.EscapeCommFunction(_hPort, Win32Com.CLRDTR))
                        _stateDtr = 0;
                    else
                        ThrowException("Unexpected Failure");
                }
            }
            get
            {
                return (_stateDtr == 1);
            }
        }

        /// <summary>
        /// Assert or remove a break condition from the transmission line
        /// </summary>
        protected bool Break
        {
            set
            {
                if (_stateBrk > 1) return;
                CheckOnline();
                if (value)
                {
                    if (Win32Com.EscapeCommFunction(_hPort, Win32Com.SETBREAK))
                        _stateBrk = 0;
                    else
                        ThrowException("Unexpected Failure");
                }
                else
                {
                    if (Win32Com.EscapeCommFunction(_hPort, Win32Com.CLRBREAK))
                        _stateBrk = 0;
                    else
                        ThrowException("Unexpected Failure");
                }
            }
            get
            {
                return (_stateBrk == 1);
            }
        }

        /// <summary>
        /// Override this to provide processing after the port is openned (i.e. to configure remote
        /// device or just check presence).
        /// </summary>
        /// <returns>false to close the port again</returns>
        protected virtual bool AfterOpen() { return true; }

        /// <summary>
        /// Override this to provide processing prior to port closure.
        /// </summary>
        /// <param name="error">True if closing due to an error</param>
        protected virtual void BeforeClose(bool error) { }

        public event Action<byte> DataReceived;
        /// <summary>
        /// Override this to process received bytes.
        /// </summary>
        /// <param name="ch">The byte that was received</param>
        protected void OnRxChar(byte ch)
        {
            if (DataReceived != null)
                DataReceived(ch);
        }

        /// <summary>
        /// Override this to take action when transmission is complete (i.e. all bytes have actually
        /// been sent, not just queued).
        /// </summary>
        protected virtual void OnTxDone() { }

        /// <summary>
        /// Override this to take action when a break condition is detected on the input line.
        /// </summary>
        protected virtual void OnBreak() { }

        /// <summary>
        /// Override this to take action when a ring condition is signalled by an attached modem.
        /// </summary>
        protected virtual void OnRing() { }

        /// <summary>
        /// Override this to take action when one or more modem status inputs change state
        /// </summary>
        /// <param name="mask">The status inputs that have changed state</param>
        /// <param name="state">The state of the status inputs</param>
        protected virtual void OnStatusChange(ModemStatus mask, ModemStatus state) { }

        /// <summary>
        /// Override this to take action when the reception thread closes due to an exception being thrown.
        /// </summary>
        /// <param name="e">The exception which was thrown</param>
        protected virtual void OnRxException(Exception e) { }

        private void ReceiveThread()
        {
            var buf = new Byte[1];

            var sg = new AutoResetEvent(false);
            var ov = new OVERLAPPED();
            var unmanagedOv = Marshal.AllocHGlobal(Marshal.SizeOf(ov));
            ov.Offset = 0; ov.OffsetHigh = 0;
            ov.hEvent = sg.Handle;
            Marshal.StructureToPtr(ov, unmanagedOv, true);

            uint eventMask = 0;
            var uMask = Marshal.AllocHGlobal(Marshal.SizeOf(eventMask));

            try
            {
                while (true)
                {
                    if (!Win32Com.SetCommMask(_hPort, Win32Com.EV_RXCHAR | Win32Com.EV_TXEMPTY | Win32Com.EV_CTS | Win32Com.EV_DSR
                        | Win32Com.EV_BREAK | Win32Com.EV_RLSD | Win32Com.EV_RING | Win32Com.EV_ERR))
                    {
                        throw new CommPortException("IO Error [001]");
                    }
                    Marshal.WriteInt32(uMask, 0);
                    if (!Win32Com.WaitCommEvent(_hPort, uMask, unmanagedOv))
                    {
                        if (Marshal.GetLastWin32Error() == Win32Com.ERROR_IO_PENDING)
                        {
                            sg.WaitOne();
                        }
                        else
                        {
                            throw new CommPortException("IO Error [002]");
                        }
                    }
                    eventMask = (uint)Marshal.ReadInt32(uMask);
                    if ((eventMask & Win32Com.EV_ERR) != 0)
                    {
                        UInt32 errs;
                        if (Win32Com.ClearCommError(_hPort, out errs, IntPtr.Zero))
                        {
                            var s = new StringBuilder("UART Error: ", 40);
                            if ((errs & Win32Com.CE_FRAME) != 0) s = s.Append("Framing,");
                            if ((errs & Win32Com.CE_IOE) != 0) s = s.Append("IO,");
                            if ((errs & Win32Com.CE_OVERRUN) != 0) s = s.Append("Overrun,");
                            if ((errs & Win32Com.CE_RXOVER) != 0) s = s.Append("Receive Cverflow,");
                            if ((errs & Win32Com.CE_RXPARITY) != 0) s = s.Append("Parity,");
                            if ((errs & Win32Com.CE_TXFULL) != 0) s = s.Append("Transmit Overflow,");
                            s.Length = s.Length - 1;
                            throw new CommPortException(s.ToString());
                        }
                        throw new CommPortException("IO Error [003]");
                    }
                    if ((eventMask & Win32Com.EV_RXCHAR) != 0)
                    {
                        uint gotbytes;
                        do
                        {
                            if (!Win32Com.ReadFile(_hPort, buf, 1, out gotbytes, unmanagedOv))
                            {
                                if (Marshal.GetLastWin32Error() == Win32Com.ERROR_IO_PENDING)
                                {
                                    Win32Com.CancelIo(_hPort);
                                    gotbytes = 0;
                                }
                                else
                                {
                                    throw new CommPortException("IO Error [004]");
                                }
                            }
                            if (gotbytes == 1) OnRxChar(buf[0]);
                            
                        } while (gotbytes > 0);
                    }
                    if ((eventMask & Win32Com.EV_TXEMPTY) != 0)
                    {
                        OnTxDone();
                    }
                    if ((eventMask & Win32Com.EV_BREAK) != 0) OnBreak();

                    uint i = 0;
                    if ((eventMask & Win32Com.EV_CTS) != 0) i |= Win32Com.MS_CTS_ON;
                    if ((eventMask & Win32Com.EV_DSR) != 0) i |= Win32Com.MS_DSR_ON;
                    if ((eventMask & Win32Com.EV_RLSD) != 0) i |= Win32Com.MS_RLSD_ON;
                    if ((eventMask & Win32Com.EV_RING) != 0) i |= Win32Com.MS_RING_ON;
                    if (i != 0)
                    {
                        uint f;
                        if (!Win32Com.GetCommModemStatus(_hPort, out f)) throw new CommPortException("IO Error [005]");
                        OnStatusChange(new ModemStatus(i), new ModemStatus(f));
                    }
                }
            }
            catch (Exception e)
            {
                if (uMask != IntPtr.Zero) Marshal.FreeHGlobal(uMask);
                if (unmanagedOv != IntPtr.Zero) Marshal.FreeHGlobal(unmanagedOv);
                if (!(e is ThreadAbortException))
                {
                    _rxException = e;
                    OnRxException(e);
                }
            }
        }

        private bool CheckOnline()
        {
            if ((_rxException != null) && (!_rxExceptionReported))
            {
                _rxExceptionReported = true;
                ThrowException("rx");
            }
            if (_online)
            {
                uint f;
                if (Win32Com.GetHandleInformation(_hPort, out f)) return true;
                ThrowException("Offline");
                return false;
            }
            if (_auto)
            {
                if (Open()) return true;
            }
            ThrowException("Offline");
            return false;
        }



        /// <summary>
        /// Port Name
        /// </summary>
        public string PortName { get; set; }
        /// <summary>
        /// Baud Rate (default: 2400) unsupported rates will throw "Bad settings"
        /// </summary>
        public int BaudRate = 115200;
        /// <summary>
        /// The parity checking scheme (default: none)
        /// </summary>
        public Parity Parity = Parity.None;
        /// <summary>
        /// Number of databits 1..8 (default: 8) unsupported values will throw "Bad settings"
        /// </summary>
        public int DataBits = 8;
        /// <summary>
        /// Number of stop bits (default: one)
        /// </summary>
        public StopBits StopBits = StopBits.one;
        /// <summary>
        /// If true, transmission is halted unless CTS is asserted by the remote station (default: false)
        /// </summary>
        public bool TxFlowCts;
        /// <summary>
        /// If true, transmission is halted unless DSR is asserted by the remote station (default: false)
        /// </summary>
        public bool TxFlowDsr;
        /// <summary>
        /// If true, transmission is halted when Xoff is received and restarted when Xon is received (default: false)
        /// </summary>
        public bool TxFlowX;
        /// <summary>
        /// If false, transmission is suspended when this station has sent Xoff to the remote station (default: true)
        /// Set false if the remote station treats any character as an Xon.
        /// </summary>
        public bool TxWhenRxXoff = true;
        /// <summary>
        /// If true, received characters are ignored unless DSR is asserted by the remote station (default: false)
        /// </summary>
        public bool RxGateDsr;
        /// <summary>
        /// If true, Xon and Xoff characters are sent to control the data flow from the remote station (default: false)
        /// </summary>
        public bool RxFlowX;
        /// <summary>
        /// Specifies the use to which the RTS output is put (default: none)
        /// </summary>
        public HsOutput UseRts = HsOutput.None;
        /// <summary>
        /// Specidies the use to which the DTR output is put (default: none)
        /// </summary>
        public HsOutput UseDtr = HsOutput.None;
        /// <summary>
        /// The character used to signal Xon for X flow control (default: DC1)
        /// </summary>
        public ASCII XonChar = ASCII.DC1;
        /// <summary>
        /// The character used to signal Xoff for X flow control (default: DC3)
        /// </summary>
        public ASCII XoffChar = ASCII.DC3;
        /// <summary>
        /// The number of free bytes in the reception queue at which flow is disabled (default: 2048)
        /// </summary>
        public int RxHighWater = 2048;
        /// <summary>
        /// The number of bytes in the reception queue at which flow is re-enabled (default: 512)
        /// </summary>
        public int RxLowWater = 512;
        /// <summary>
        /// Multiplier. Max time for Send in ms = (Multiplier * Characters) + Constant
        /// (default: 0 = No timeout)
        /// </summary>
        public int SendTimeoutMultiplier;
        /// <summary>
        /// Constant.  Max time for Send in ms = (Multiplier * Characters) + Constant (default: 0)
        /// </summary>
        public int SendTimeoutConstant;
        /// <summary>
        /// Requested size for receive queue (default: 0 = use operating system default)
        /// </summary>
        public int RxQueue;
        /// <summary>
        /// Requested size for transmit queue (default: 0 = use operating system default)
        /// </summary>
        public int TxQueue;
        /// <summary>
        /// If true, the port will automatically re-open on next send if it was previously closed due
        /// to an error (default: false)
        /// </summary>
        public bool AutoReopen;

        /// <summary>
        /// If true, subsequent Send commands wait for completion of earlier ones enabling the results
        /// to be checked. If false, errors, including timeouts, may not be detected, but performance
        /// may be better.
        /// </summary>
        public bool CheckAllSends = true;

        private Handshake _handShake;
        public Handshake Handshake
        {
            get { return _handShake; }
            set
            {
                _handShake = value;
                switch (_handShake)
                {
                    case Handshake.None:
                        TxFlowCts = false; TxFlowDsr = false; TxFlowX = false;
                        RxFlowX = false; UseRts = HsOutput.Online; UseDtr = HsOutput.Online;
                        TxWhenRxXoff = true; RxGateDsr = false;
                        break;
                    case Handshake.XonXoff:
                        TxFlowCts = false; TxFlowDsr = false; TxFlowX = true;
                        RxFlowX = true; UseRts = HsOutput.Online; UseDtr = HsOutput.Online;
                        TxWhenRxXoff = true; RxGateDsr = false;
                        XonChar = ASCII.DC1; XoffChar = ASCII.DC3;
                        break;
                    case Handshake.CtsRts:
                        TxFlowCts = true; TxFlowDsr = false; TxFlowX = false;
                        RxFlowX = false; UseRts = HsOutput.Handshake; UseDtr = HsOutput.Online;
                        TxWhenRxXoff = true; RxGateDsr = false;
                        break;
                    case Handshake.DsrDtr:
                        TxFlowCts = false; TxFlowDsr = true; TxFlowX = false;
                        RxFlowX = false; UseRts = HsOutput.Online; UseDtr = HsOutput.Handshake;
                        TxWhenRxXoff = true; RxGateDsr = false;
                        break;
                }
            }
        }
    }
}