/// <summary>
/// Write data to a comm object.
/// </summary>
/// <param name="buf">Buffer to write from</param>
/// <param name="nToSend">Number to buyes to send.</param>
/// <param name="nSent">Number of actually bytes sent.</param>
/// <param name="olMem">Pointer to overlap struct.</param>
/// <returns>True if executed successfully.</returns>
internal bool Write(byte[] buf, uint nToSend, out uint nSent, Win32Ovrlap ovlap)
{
// Write done pre/post check.
bool postCheck = true;
// Wait until last write done.
if(postCheck == false)
{
if(ovlap.MemPtr != IntPtr.Zero)
{
while(this.nUnsent > 0)
{
if(ovlap.Get(out nSent, true))
{
this.nUnsent -= nSent;
}
}
}
}
// Send data buffer.
bool status = WriteFile(this.handle, buf, nToSend, out nSent, ovlap.MemPtr);
this.nUnsent = nToSend-nSent;
// Return status.
if(status == false)
{
int error = Marshal.GetLastWin32Error();
// Wait until this write done.
if(postCheck == true)
{
if(error == ERROR_IO_PENDING)
{
while(this.nUnsent > 0)
{
if(ovlap.Get(out nSent, true))
{
this.nUnsent -= nSent;
}
}
}
else
{
this.SetFault("WriteFile()", error);
return false;
}
}
else
{
if(error != ERROR_IO_PENDING)
{
this.SetFault("WriteFile()", error);
return false;
}
nSent = nToSend; // assume write will pass.
}
}
return true;
}
/// <summary>
/// Closes and destroys the com port.
/// </summary>
protected void Destroy()
{
// Cancel I/O, kill receiver & close port.
if(this.portOpen)
{
this.port.Cancel();
if(this.rxThread != null)
{
this.rxThread.Abort();
this.rxThread = null;
}
this.port.Close();
this.portOpen = false;
}
// Reinit resources.
this.dcb = null;
this.port = null;
this.stats = null;
this.props = null;
this.tmout = null;
this.rxOvr = null;
this.txOvr = null;
this.escape = null;
this.writeEvent = null;
this.recvrEvent = null;
return;
}
/// <summary>
/// Main receiver thread for this com port instance.
/// </summary>
private void ReceiveThread()
{
// Create locals.
uint firedEvent = 0;
uint nBytes = 0;
byte[] buf = new Byte[1];
// Create thread signal (initial state is non-signaled).
AutoResetEvent signal = new AutoResetEvent(false);
// Create overlap memory pointer. Install signal.
this.rxOvr = new Win32Ovrlap(port.Handle, signal.Handle);
// Instantiate the event class.
this.events = new Win32Events(rxOvr.MemPtr);
// Instantiate the modem signal class.
this.modem = new Win32Modem();
// Set initial modem signal states.
this.Signals();
// Signal the main thread that
// the receive thread is started.
this.recvrEvent.Set();
try
{
while(true)
{
// Arm the event monitoring mask.
if(this.events.Set(this.port.Handle, Win32Events.EV_DEFAULT))
{
// Wait for any armed event to occur.
this.events.Wait(this.port.Handle, signal);
// Get mask of fired events.
firedEvent = this.events.GetMask;
// Error event (override).
if((firedEvent & Win32Events.EV_ERR) != 0)
{
if(this.stats.Reset(this.port.Handle) == false)
{
if(this.stats.Status == Win32Status.CE_BREAK)
{
firedEvent &= ~Win32Events.EV_BREAK;
}
else
{
this.CommError(this.stats.Fault);
}
}
}
else
{
// Receive event (override).
if(((firedEvent & Win32Events.EV_RXCHAR) != 0) && (this.immediate))
{
do
{
nBytes = 0;
if(this.port.Read(buf, 1, out nBytes, this.rxOvr.MemPtr))
{
if(nBytes == 1)
this.OnRxChar(buf);
}
} while(nBytes > 0);
}
// TX queue empty event (override).
if((firedEvent & Win32Events.EV_TXEMPTY) != 0)
this.OnTxDone();
// Line break event (override).
if((firedEvent & Win32Events.EV_BREAK) != 0)
this.OnBreak();
// Modem signal change event(s) (override).
if((firedEvent & Win32Events.EV_MODEM) > 0)
{
this.modem.Get(this.port.Handle);
if((firedEvent & Win32Events.EV_CTS) > 0)
this.OnCTS(this.modem.CtsState);
if((firedEvent & Win32Events.EV_DSR) > 0)
this.OnDSR(this.modem.DsrState);
if((firedEvent & Win32Events.EV_RLSD) > 0)
this.OnRLSD(this.modem.RlsdState);
if((firedEvent & Win32Events.EV_RING) > 0)
this.OnRING(this.modem.RingState);
}
}
}
}
}
catch(Exception e)
{
if((e is ThreadAbortException))
{
this.modem = null;
this.events = null;
this.rxOvr = null;
}
else
{
this.CommError("Receiver Exception: " + e.Message);
}
}
}
/// <summary>
/// Create & opens the com port and configures it with the required settings.
/// </summary>
/// <param name="cfg">Reference to port user config.</param>
/// <returns>True if port opened successfully.</returns>
protected bool Create(SerialCnfg cfg)
{
// If port already open, return.
if(portOpen)
{
this.CommError("Com Port Already Open.");
return false;
}
// Init members.
this.fault = "";
this.rxThread = null;
this.writeEvent = new ManualResetEvent(false);
this.recvrEvent = new ManualResetEvent(false);
// Copy config to DCB.
this.dcb = new Win32DCB(cfg);
// Create handle to comm port.
this.port = new Win32Com();
if((this.portOpen = this.port.Open(cfg.PortName, true)) == false)
{
this.CommError(this.port.Fault);
return false;
}
this.portName = cfg.PortName;
// Instantiate support classes.
this.stats = new Win32Status();
this.tmout = new Win32Tmout();
this.props = new Win32Props();
this.escape = new Win32Escape(port.Handle);
// Set read/write timeouts.
this.tmout.WriteConstant = cfg.TxTmoConst;
this.tmout.WriteMultiplier = cfg.TxTmoMulti;
if(this.tmout.Set(this.port.Handle) == false)
{
this.CommError(this.tmout.Fault);
this.Destroy();
return false;
}
// Overide OS default queue sizes.
if((cfg.RxQueLen != 0) || (cfg.TxQueLen != 0))
{
if(this.props.Set(this.port.Handle, (uint)cfg.RxQueLen, (uint)cfg.TxQueLen) == false)
{
this.Destroy();
this.CommError(this.props.Fault);
return false;
}
}
// Get the current properties.
if(this.props.Get(this.port.Handle) == false)
{
this.Destroy();
this.CommError(this.props.Fault);
return false;
}
// Set flow control limits.
this.dcb.Limits(cfg, this.props.RxCurSize);
// Update the port settings.
if(this.dcb.Set(this.port.Handle) == false)
{
this.Destroy();
this.CommError(this.dcb.Fault);
return false;
}
// XON/OFF extended functionality.
this.escape.XOFFavailable = true;
// RTS extended functionality.
if(cfg.RtsControl == PinState.Disable)
this.escape.RTS = false;
else if(cfg.RtsControl == PinState.Enable)
this.escape.RTS = true;
else if(cfg.RtsControl == PinState.Handshake)
this.escape.RTSavailable = false;
// DTR extended functionality.
if(cfg.DtrControl == PinState.Disable)
this.escape.DTR = false;
else if(cfg.DtrControl == PinState.Enable)
this.escape.DTR = true;
else if(cfg.DtrControl == PinState.Toggle)
this.escape.DTR = false;
else if(cfg.DtrControl == PinState.Handshake)
this.escape.DTRavailable = false;
// Create TX overlap memory pointer.
this.txOvr = new Win32Ovrlap(this.port.Handle, this.writeEvent.Handle);
// Set the receiver mode.
this.immediate = cfg.ReceiveMode;
// Start the receiver thread.
this.rxThread = new Thread(new ThreadStart(ReceiveThread));
this.rxThread.Name = "COMReceiver";
this.rxThread.Priority = ThreadPriority.AboveNormal;
this.rxThread.Start();
// Wait for receive thread to start.
this.recvrEvent.WaitOne(500, false);
// Port opened OK.
return true;
}
