port.cs

win CE .net Serial port class lib

					{
						m_CommAPI.WriteFile(hPort, txBuffer, ptxBuffer, ref written, txOverlapped);
						ptxBuffer = 0;
					}
				}
			}
		}

		/// <summary>
		/// The Port's input buffer.  Incoming data is read from here and a read will pull InputLen bytes from the buffer
		/// <seealso cref="InputLen"/>
		/// </summary>
		public byte[] Input
		{
			get
			{
				if(!isOpen) return null;

				int dequeueLength = 0;

				// lock the rx FIFO while reading
				rxBufferBusy.WaitOne();

				// how much data are we *actually* going to return from the call?
				if(inputLength == 0)
					dequeueLength = rxFIFO.Count;  // pull the entire buffer
				else
					dequeueLength = (inputLength < rxFIFO.Count) ? inputLength : rxFIFO.Count;

				byte[] data = new byte[dequeueLength];

				// dequeue the data
				for(int p = 0 ; p < dequeueLength ; p++)
					data[p] = (byte)rxFIFO.Dequeue();

				// release the mutex so the Rx thread can continue
				rxBufferBusy.ReleaseMutex();

				return data;
			}
		}

		/// <summary>
		/// The length of the input buffer
		/// </summary>
		public int InputLen
		{
			get
			{
				return inputLength;
			}
			set
			{
				inputLength = value;
			}
		}

		/// <summary>
		/// The actual amount of data in the input buffer
		/// </summary>
		public int InBufferCount
		{
			get
			{
				if(!isOpen) return 0;

				return rxFIFO.Count;
			}
		}

		/// <summary>
		/// The actual amount of data in the output buffer
		/// </summary>
		public int OutBufferCount
		{
			get
			{
				if(!isOpen) return 0;

				return ptxBuffer;
			}
		}

		/// <summary>
		/// The number of bytes that the receive buffer must exceed to trigger a Receive event
		/// </summary>
		public int RThreshold
		{
			get
			{
				return rthreshold;
			}
			set
			{
				rthreshold = value;
			}
		}

		/// <summary>
		/// The number of bytes that the transmit buffer must exceed to trigger a Transmit event
		/// </summary>
		public int SThreshold
		{
			get
			{
				return sthreshold;
			}
			set
			{
				sthreshold = value;
			}
		}

		/// <summary>
		/// Send or check for a communications BREAK event
		/// </summary>
		public bool Break
		{
			get 
			{
				if(!isOpen) return false;

				return (brk == 1);
			}		
			set 
			{
				if(!isOpen) return;
				if(brk < 0) return;
				if(hPort == (IntPtr)CommAPI.INVALID_HANDLE_VALUE) return;

				if (value)
				{
					if (m_CommAPI.EscapeCommFunction(hPort, CommEscapes.SETBREAK))
						brk = 1;
					else
						throw new CommPortException("Failed to set break!");
				}
				else
				{
					if (m_CommAPI.EscapeCommFunction(hPort, CommEscapes.CLRBREAK))
						brk = 0;
					else
						throw new CommPortException("Failed to clear break!");
				}
			}
		}

		/// <summary>
		/// Returns whether or not the current port support a DTR signal
		/// </summary>
		public bool DTRAvailable
		{
			get
			{
				return dtravail;
			}
		}

		/// <summary>
		/// Gets or sets the current DTR line state (true = 1, false = 0)
		/// </summary>
		public bool DTREnable
		{
			get
			{
				return (dtr == 1);
			}
			set
			{
				if(dtr < 0) return;
				if(hPort == (IntPtr)CommAPI.INVALID_HANDLE_VALUE) return;

				if (value)
				{
					if (m_CommAPI.EscapeCommFunction(hPort, CommEscapes.SETDTR))
						dtr = 1;
					else
						throw new CommPortException("Failed to set DTR!");
				}
				else
				{
					if (m_CommAPI.EscapeCommFunction(hPort, CommEscapes.CLRDTR))
						dtr = 0;
					else
						throw new CommPortException("Failed to clear DTR!");
				}
			}
		}

		/// <summary>
		/// Returns whether or not the current port support an RTS signal
		/// </summary>
		public bool RTSAvailable
		{
			get
			{
				return rtsavail;
			}
		}

		/// <summary>
		/// Gets or sets the current RTS line state (true = 1, false = 0)
		/// </summary>
		public bool RTSEnable
		{
			get
			{
				return (rts == 1);
			}
			set
			{
				if(rts < 0) return;
				if(hPort == (IntPtr)CommAPI.INVALID_HANDLE_VALUE) return;

				if (value)
				{
					if (m_CommAPI.EscapeCommFunction(hPort, CommEscapes.SETRTS))
						rts = 1;
					else
						throw new CommPortException("Failed to set RTS!");
				}
				else
				{
					if (m_CommAPI.EscapeCommFunction(hPort, CommEscapes.CLRRTS))
						rts = 0;
					else
						throw new CommPortException("Failed to clear RTS!");
				}
			}
		}
		/// <summary>
		/// Gets or sets the com port for IR use (true = 1, false = 0)
		/// </summary>

		public bool IREnable
		{
			get
			{
				return (setir == 1);
			}
			set
			{
				if(setir < 0) return;
				if(hPort == (IntPtr)CommAPI.INVALID_HANDLE_VALUE) return;

				if (value)
				{
					if (m_CommAPI.EscapeCommFunction(hPort, CommEscapes.SETIR))
						setir = 1;
					else
						throw new CommPortException("Failed to set IR!");
				}
				else
				{
					if (m_CommAPI.EscapeCommFunction(hPort, CommEscapes.CLRIR))
						setir = 0;
					else
						throw new CommPortException("Failed to clear IR!");
				}
			}
		}

		/// <summary>
		/// Get or Set the Port's DetailedPortSettings
		/// </summary>
		public DetailedPortSettings DetailedSettings
		{
			get
			{
				return portSettings;
			}
			set
			{
				portSettings = value;
				UpdateSettings();
			}
		}

		/// <summary>
		/// Get or Set the Port's BasicPortSettings
		/// </summary>
		public BasicPortSettings Settings
		{
			get
			{
				return portSettings.BasicSettings;
			}
			set
			{
				portSettings.BasicSettings = value;
				UpdateSettings();
			}
		}

		/// <summary>
		/// <code>GetPortProperties initializes the commprop member of the port object</code>
		/// </summary>
		/// <returns></returns>
		private bool GetPortProperties()
		{
			bool success;

			success=m_CommAPI.GetCommProperties(hPort,Capabilities);

			return (success);
		}

		private void CommEventThread()
		{
			CommEventFlags	eventFlags	= new CommEventFlags();
			byte[]			readbuffer	= new Byte[rxBufferSize];
			int				bytesread	= 0;
			AutoResetEvent	rxevent		= new AutoResetEvent(false);

			// specify the set of events to be monitored for the port.
			if(CommAPI.FullFramework)
			{
				m_CommAPI.SetCommMask(hPort, CommEventFlags.ALLPC);

				// set up the overlapped IO
				OVERLAPPED o = new OVERLAPPED();
				rxOverlapped = LocalAlloc(0x40, Marshal.SizeOf(o));
				o.Offset = 0; 
				o.OffsetHigh = 0;
				o.hEvent = rxevent.Handle;
				Marshal.StructureToPtr(o, rxOverlapped, true);
			}
			else
			{
				m_CommAPI.SetCommMask(hPort, CommEventFlags.ALLCE);
			}
			

			try
			{
				// let Open() know we're started
				threadStarted.Set();

				#region >>>> thread loop <<<<
				while(hPort != (IntPtr)CommAPI.INVALID_HANDLE_VALUE)
				{
					// wait for a Comm event
					if(!m_CommAPI.WaitCommEvent(hPort, ref eventFlags))
					{
						int e = Marshal.GetLastWin32Error();

						if(e == (int)APIErrors.ERROR_IO_PENDING)
						{
							// IO pending so just wait and try again
							rxevent.WaitOne();
							Thread.Sleep(0);
							continue;
						}

						if(e == (int)APIErrors.ERROR_INVALID_HANDLE)
						{
							// Calling Port.Close() causes hPort to become invalid
							// Since Thread.Abort() is unsupported in the CF, we must
							// accept that calling Close will throw an error here.

							// Close signals the closeEvent, so wait on it
							// We wait 1 second, though Close should happen much sooner
							int eventResult = m_CommAPI.WaitForSingleObject(closeEvent, 1000);

							if(eventResult == (int)APIConstants.WAIT_OBJECT_0)
							{
								// the event was set so close was called
								hPort = (IntPtr)CommAPI.INVALID_HANDLE_VALUE;
					
								// reset our ResetEvent for the next call to Open
								threadStarted.Reset();

								if(isOpen) // this should not be the case...if so, throw an exception for the owner
								{
									string error = String.Format("Wait Failed: {0}", e);
									throw new CommPortException(error);
								}

								return;
							}
						}

						// WaitCommEvent failed
						// 995 means an exit was requested (thread killed)
						if(e == 995)
						{
							return;
						}
						else
						{
							string error = String.Format("Wait Failed: {0}", e);
							throw new CommPortException(error);
						}
					}

					// Re-specify the set of events to be monitored for the port.
					if(CommAPI.FullFramework)
					{
						m_CommAPI.SetCommMask(hPort, CommEventFlags.ALLPC);
					}
					else
					{
						m_CommAPI.SetCommMask(hPort, CommEventFlags.ALLCE);
					}

					// check the event for errors
					#region >>>> error checking <<<<
					if(((uint)eventFlags & (uint)CommEventFlags.ERR) != 0)
					{
						CommErrorFlags errorFlags = new CommErrorFlags();
						CommStat commStat = new CommStat();

						// get the error status
						if(!m_CommAPI.ClearCommError(hPort, ref errorFlags, commStat))
						{
							// ClearCommError failed!
							string error = String.Format("ClearCommError Failed: {0}", Marshal.GetLastWin32Error());
							throw new CommPortException(error);
						}

						if(((uint)errorFlags & (uint)CommErrorFlags.BREAK) != 0)
						{
							// BREAK can set an error, so make sure the BREAK bit is set an continue
							eventFlags |= CommEventFlags.BREAK;
						}
						else
						{
							// we have an error.  Build a meaningful string and throw an exception
							StringBuilder s = new StringBuilder("UART Error: ", 80);
							if ((errorFlags & CommErrorFlags.FRAME) != 0) 
							{ s = s.Append("Framing,");	}
							if ((errorFlags & CommErrorFlags.IOE) != 0) 
							{ s = s.Append("IO,"); }
							if ((errorFlags & CommErrorFlags.OVERRUN) != 0)
							{ s = s.Append("Overrun,"); }
							if ((errorFlags & CommErrorFlags.RXOVER) != 0)
							{ s = s.Append("Receive Overflow,"); }
							if ((errorFlags & CommErrorFlags.RXPARITY) != 0)
							{ s = s.Append("Parity,"); }
							if ((errorFlags & CommErrorFlags.TXFULL) != 0)
							{ s = s.Append("Transmit Overflow,"); }

							// no known bits are set
							if(s.Length == 12)
							{ s = s.Append("Unknown"); }
					
							// raise an error event
							if(OnError != null)
								OnError(s.ToString());

							continue;
						}
					} // if(((uint)eventFlags & (uint)CommEventFlags.ERR) != 0)
					#endregion

					#region >>>> line status checking <<<<
					// check for status changes
					uint status = 0;
					m_CommAPI.GetCommModemStatus(hPort, ref status);

					// check the CTS
					if(((uint)eventFlags & (uint)CommEventFlags.CTS) != 0)
					{
						if(CTSChange != null)
							CTSChange((status & (uint)CommModemStatusFlags.MS_CTS_ON) != 0);
					}

					// check the DSR
					if(((uint)eventFlags & (uint)CommEventFlags.DSR) != 0)
					{
						if(DSRChange != null)
							DSRChange((status & (uint)CommModemStatusFlags.MS_DSR_ON) != 0);
					}
				
					// check for a RING
					if(((uint)eventFlags & (uint)CommEventFlags.RING) != 0)
					{
						if(RingChange != null)
							RingChange((status & (uint)CommModemStatusFlags.MS_RING_ON) != 0);
					}

					// check for a RLSD
					if(((uint)eventFlags & (uint)CommEventFlags.RLSD) != 0)
					{
						if(RLSDChange != null)
							RLSDChange((status & (uint)CommModemStatusFlags.MS_RLSD_ON) != 0);
					}

					// check for TXEMPTY
					if(((uint)eventFlags & (uint)CommEventFlags.TXEMPTY) != 0)
						if(TxDone != null) { TxDone(); }

					// check for RXFLAG
					if(((uint)eventFlags & (uint)CommEventFlags.RXFLAG) != 0)
						if(FlagCharReceived != null) { FlagCharReceived(); }
					
					// check for POWER
					if(((uint)eventFlags & (uint)CommEventFlags.POWER) != 0)
						if(PowerEvent != null) { PowerEvent(); }

					// check for high-water state
					if((eventFlags & CommEventFlags.RX80FULL) != 0)
						if(HighWater != null) { HighWater(); }
					#endregion

					#region >>>> Receive data subsection <<<<
					// check for RXCHAR
					if((eventFlags & CommEventFlags.RXCHAR) != 0) 
					{
						do 
						{
							// make sure the port handle is valid
							if(hPort == (IntPtr)CommAPI.INVALID_HANDLE_VALUE)
							{
								bytesread = 0;
								break;
							}

							// data came in, put it in the buffer and set the event
							if (!m_CommAPI.ReadFile(hPort, readbuffer, rxBufferSize, ref bytesread, rxOverlapped)) 
							{
								string errString = String.Format("ReadFile Failed: {0}", Marshal.GetLastWin32Error());
								if(OnError != null)
									OnError(errString);

								return;
							}
							if (bytesread >= 1) 
							{
								// take the mutex
								rxBufferBusy.WaitOne();

								// put the data into the fifo
								// this *may*  be a perf problem and needs testing
								for(int b = 0 ; b < bytesread ; b++)
									rxFIFO.Enqueue(readbuffer[b]);

								// get the FIFO length
								int fifoLength = rxFIFO.Count;

								// release the mutex
								rxBufferBusy.ReleaseMutex();

								// fire the DataReceived event every RThreshold bytes
								if((DataReceived != null) && (rthreshold != 0) && (fifoLength >= rthreshold))
								{
									DataReceived();
								}
							}
						} while (bytesread > 0);
					} // if((eventFlags & CommEventFlags.RXCHAR) != 0) 
					#endregion
				} // while(true)
				#endregion
			} // try
			catch(Exception e)
			{
				if(rxOverlapped != IntPtr.Zero) 
					LocalFree(rxOverlapped);

				if(OnError != null)
					OnError(e.Message);

				return;
			}
		}
	}
}