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   源码介绍

---

// MySerial.cpp: implementation of the CMySerial class.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "comElves.h"
#include "MySerial.h"

#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

CMySerial::CMySerial()
{
	m_hComm = NULL;

	// 初始化异步操作成员变量
	m_ov.Offset = 0;
	m_ov.OffsetHigh = 0;

	// 创建异步操作的事件成员变量
	m_ov.hEvent = NULL;

	// 初始化发送及关闭事件
	m_hWriteEvent = NULL;
	m_hShutdownEvent = NULL;
	
	//初始化发送变量
	m_szWriteBuffer = NULL;
	m_nWriteSize=1;

	// 串口监控线程出于非激活状态
	m_bThreadAlive = FALSE;

}

CMySerial::~CMySerial()
{
	do
	{
		SetEvent(m_hShutdownEvent);	// 关闭串口
	} while (m_bThreadAlive);

	
	// 如果上面没有关闭成功，则继续关闭 
	if (m_hComm != NULL)
	{
		CloseHandle(m_hComm);
		m_hComm = NULL;
	}
	// 关闭事件句柄
	if(m_hShutdownEvent!=NULL)
		CloseHandle( m_hShutdownEvent); 
	if(m_ov.hEvent!=NULL)
		CloseHandle( m_ov.hEvent ); 
	if(m_hWriteEvent!=NULL)
		CloseHandle( m_hWriteEvent ); 

	TRACE("Thread ended\n");
	delete [] m_szWriteBuffer;	//删除发送缓冲区
}
bool CMySerial::OpenSerialPort(CWnd* pParent, UINT portnr, UINT baud, char parity, UINT databits, UINT stopbits, DWORD dwCommEvents, UINT writebuffersize)
{
	assert(portnr > 0 && portnr < 5);
	assert(pParent != NULL);

	// 如果串口监控线程活动，则关闭它
	if (m_bThreadAlive)
	{
		do
		{
			SetEvent(m_hShutdownEvent);
		} while (m_bThreadAlive);
		TRACE("Thread ended\n");
	}

	// 创建串口异步通讯事件
	if (m_ov.hEvent != NULL)
		ResetEvent(m_ov.hEvent);
	else
		m_ov.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
	// 创建发送事件
	if (m_hWriteEvent != NULL)
		ResetEvent(m_hWriteEvent);
	else
		m_hWriteEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
	// 创建关闭串口事件
	if (m_hShutdownEvent != NULL)
		ResetEvent(m_hShutdownEvent);
	else
		m_hShutdownEvent = CreateEvent(NULL, TRUE, FALSE, NULL);

	// 初始化事件数组
	m_hEventArray[0] = m_hShutdownEvent;	// 最高的优先级
	m_hEventArray[1] = m_ov.hEvent;
	m_hEventArray[2] = m_hWriteEvent;

	// 初始化临界资源
	InitializeCriticalSection(&m_csCommunicationSync);
	
	// 保存串口操作窗口指针
	m_pParent = pParent;
	
	// 为发送缓冲申请空间
	if (m_szWriteBuffer != NULL)
		delete [] m_szWriteBuffer;
	m_szWriteBuffer = new char[writebuffersize];
	
	// 保存串口号
	m_nPortNr = portnr;
	
	// 将要发送的数据
	m_nWriteBufferSize = writebuffersize;
	m_dwCommEvents = dwCommEvents;

	BOOL bResult = FALSE;
	char *szPort = new char[50];
	char *szBaud = new char[50];

	// 锁定临界变量
	EnterCriticalSection(&m_csCommunicationSync);

	// 如果串口已经打开，则关闭他
	if (m_hComm != NULL)
	{
		CloseHandle(m_hComm);
		m_hComm = NULL;
	}

	// 状态信息
	sprintf(szPort, "COM%d", portnr);
	sprintf(szBaud, "baud=%d parity=%c data=%d stop=%d", baud, parity, databits, stopbits);

	// 打开串口
	m_hComm = CreateFile(szPort,						// communication port string (COMX)
					     GENERIC_READ | GENERIC_WRITE,	// read/write types
					     0,								// comm devices must be opened with exclusive access
					     NULL,							// no security attributes
					     OPEN_EXISTING,					// comm devices must use OPEN_EXISTING
					     FILE_FLAG_OVERLAPPED,			// Async I/O
					     NULL);							// template must be 0 for comm devices

	if (m_hComm == INVALID_HANDLE_VALUE)
	{
		// 打开失败
		delete [] szPort;
		delete [] szBaud;

		return FALSE;
	}

	// 超时参数
	m_CommTimeouts.ReadIntervalTimeout = 1000;
	m_CommTimeouts.ReadTotalTimeoutMultiplier = 1000;
	m_CommTimeouts.ReadTotalTimeoutConstant = 1000;
	m_CommTimeouts.WriteTotalTimeoutMultiplier = 1000;
	m_CommTimeouts.WriteTotalTimeoutConstant = 1000;

	// 设置串口参数
	if (SetCommTimeouts(m_hComm, &m_CommTimeouts))
	{						   
		if (SetCommMask(m_hComm, dwCommEvents))
		{
			if (GetCommState(m_hComm, &m_dcb))
			{
				m_dcb.EvtChar = 'q';
				m_dcb.fRtsControl = RTS_CONTROL_ENABLE;	
				if (BuildCommDCB(szBaud, &m_dcb))
				{
					if (!SetCommState(m_hComm, &m_dcb))
						ProcessErrorMessage("SetCommState()");
				}
				else
					ProcessErrorMessage("BuildCommDCB()");
			}
			else
				ProcessErrorMessage("GetCommState()");
		}
		else
			ProcessErrorMessage("SetCommMask()");
	}
	else
		ProcessErrorMessage("SetCommTimeouts()");

	delete [] szPort;
	delete [] szBaud;

	// 清空发送及接受缓冲区
	PurgeComm(m_hComm, PURGE_RXCLEAR | PURGE_TXCLEAR | PURGE_RXABORT | PURGE_TXABORT);

	// 解锁临界变量
	LeaveCriticalSection(&m_csCommunicationSync);

	TRACE("Initialisation for communicationport %d completed.\nUse Startmonitor to communicate.\n", portnr);

	return TRUE;
}
void CMySerial::ReceiveChar(CMySerial* port, COMSTAT comstat)
{
	BOOL  bRead = TRUE; 
	BOOL  bResult = TRUE;
	DWORD dwError = 0;
	DWORD BytesRead = 0;
	unsigned char RXBuff;

	for (;;) 
	{ 
		// Gain ownership of the comm port critical section.
		// This process guarantees no other part of this program 
		// is using the port object. 
		
		EnterCriticalSection(&port->m_csCommunicationSync);

		// ClearCommError() will update the COMSTAT structure and
		// clear any other errors.
		
		bResult = ClearCommError(port->m_hComm, &dwError, &comstat);

		LeaveCriticalSection(&port->m_csCommunicationSync);

		// start forever loop.  I use this type of loop because I
		// do not know at runtime how many loops this will have to
		// run. My solution is to start a forever loop and to
		// break out of it when I have processed all of the
		// data available.  Be careful with this approach and
		// be sure your loop will exit.
		// My reasons for this are not as clear in this sample 
		// as it is in my production code, but I have found this 
		// solutiion to be the most efficient way to do this.
		
		if (comstat.cbInQue == 0)
		{
			// break out when all bytes have been read
			break;
		}
						
		EnterCriticalSection(&port->m_csCommunicationSync);

		if (bRead)
		{
			bResult = ReadFile(port->m_hComm,		// Handle to COMM port 
							   &RXBuff,				// RX Buffer Pointer
							   1,					// Read one byte
							   &BytesRead,			// Stores number of bytes read
							   &port->m_ov);		// pointer to the m_ov structure
			// deal with the error code 
			if (!bResult)  
			{ 
				switch (dwError = GetLastError()) 
				{ 
					case ERROR_IO_PENDING: 	
						{ 
							// asynchronous i/o is still in progress 
							// Proceed on to GetOverlappedResults();
							bRead = FALSE;
							break;
						}
					default:
						{
							// Another error has occured.  Process this error.
							port->ProcessErrorMessage("ReadFile()");
							break;
						} 
				}
			}
			else
			{
				// ReadFile() returned complete. It is not necessary to call GetOverlappedResults()
				bRead = TRUE;
			}
		}  // close if (bRead)

		if (!bRead)
		{
			bRead = TRUE;
			bResult = GetOverlappedResult(port->m_hComm,	// Handle to COMM port 
										  &port->m_ov,		// Overlapped structure
										  &BytesRead,		// Stores number of bytes read
										  TRUE); 			// Wait flag

			// deal with the error code 
			if (!bResult)  
			{
				port->ProcessErrorMessage("GetOverlappedResults() in ReadFile()");
			}	
		}  // close if (!bRead)
				
		LeaveCriticalSection(&port->m_csCommunicationSync);

		// notify parent that a byte was received
		::SendMessage((port->m_pParent)->m_hWnd, WM_COMM_RXCHAR, (WPARAM) RXBuff, (LPARAM) port->m_nPortNr);
	} // end forever loop

}
void CMySerial::ProcessErrorMessage(char* ErrorText)
{
	char *Temp = new char[200];
	
	LPVOID lpMsgBuf;

	FormatMessage( 
		FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
		NULL,
		GetLastError(),
		MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
		(LPTSTR) &lpMsgBuf,
		0,
		NULL 
	);

	sprintf(Temp, "WARNING:  %s Failed with the following error: \n%s\nPort: %d\n", (char*)ErrorText, lpMsgBuf, m_nPortNr); 
	MessageBox(NULL, Temp, "Application Error", MB_ICONSTOP);

	LocalFree(lpMsgBuf);
	delete [] Temp;
}
UINT CMySerial::CommThread(LPVOID pParam)
{
	// Cast the void pointer passed to the thread back to
	// a pointer of CMySerial class
	CMySerial *port = (CMySerial*)pParam;
	
	// Set the status variable in the dialog class to
	// TRUE to indicate the thread is running.
	port->m_bThreadAlive = TRUE;	
		
	// Misc. variables
	DWORD BytesTransfered = 0; 
	DWORD Event = 0;
	DWORD CommEvent = 0;
	DWORD dwError = 0;
	COMSTAT comstat;
	BOOL  bResult = TRUE;
		
	// Clear comm buffers at startup
	if (port->m_hComm)		// check if the port is opened
		PurgeComm(port->m_hComm, PURGE_RXCLEAR | PURGE_TXCLEAR | PURGE_RXABORT | PURGE_TXABORT);

	// begin forever loop.  This loop will run as long as the thread is alive.
	for (;;) 
	{ 

		// Make a call to WaitCommEvent().  This call will return immediatly
		// because our port was created as an async port (FILE_FLAG_OVERLAPPED
		// and an m_OverlappedStructerlapped structure specified).  This call will cause the 
		// m_OverlappedStructerlapped element m_OverlappedStruct.hEvent, which is part of the m_hEventArray to 
		// be placed in a non-signeled state if there are no bytes available to be read,
		// or to a signeled state if there are bytes available.  If this event handle 
		// is set to the non-signeled state, it will be set to signeled when a 
		// character arrives at the port.

		// we do this for each port!

		bResult = WaitCommEvent(port->m_hComm, &Event, &port->m_ov);

		if (!bResult)  
		{ 
			// If WaitCommEvent() returns FALSE, process the last error to determin
			// the reason..
			switch (dwError = GetLastError()) 
			{ 
			case ERROR_IO_PENDING: 	
				{ 
					// This is a normal return value if there are no bytes
					// to read at the port.
					// Do nothing and continue
					break;
				}
			case 87:
				{
					// Under Windows NT, this value is returned for some reason.
					// I have not investigated why, but it is also a valid reply
					// Also do nothing and continue.
					break;
				}
			default:
				{
					// All other error codes indicate a serious error has
					// occured.  Process this error.
					port->ProcessErrorMessage("WaitCommEvent()");
					break;
				}
			}
		}
		else
		{
			// If WaitCommEvent() returns TRUE, check to be sure there are
			// actually bytes in the buffer to read.  
			//
			// If you are reading more than one byte at a time from the buffer 
			// (which this program does not do) you will have the situation occur 
			// where the first byte to arrive will cause the WaitForMultipleObjects() 
			// function to stop waiting.  The WaitForMultipleObjects() function 
			// resets the event handle in m_OverlappedStruct.hEvent to the non-signelead state
			// as it returns.  
			//
			// If in the time between the reset of this event and the call to 
			// ReadFile() more bytes arrive, the m_OverlappedStruct.hEvent handle will be set again
			// to the signeled state. When the call to ReadFile() occurs, it will 
			// read all of the bytes from the buffer, and the program will
			// loop back around to WaitCommEvent().
			// 
			// At this point you will be in the situation where m_OverlappedStruct.hEvent is set,
			// but there are no bytes available to read.  If you proceed and call
			// ReadFile(), it will return immediatly due to the async port setup, but
			// GetOverlappedResults() will not return until the next character arrives.
			//
			// It is not desirable for the GetOverlappedResults() function to be in 
			// this state.  The thread shutdown event (event 0) and the WriteFile()
			// event (Event2) will not work if the thread is blocked by GetOverlappedResults().
			//
			// The solution to this is to check the buffer with a call to ClearCommError().
			// This call will reset the event handle, and if there are no bytes to read
			// we can loop back through WaitCommEvent() again, then proceed.
			// If there are really bytes to read, do nothing and proceed.
		
			bResult = ClearCommError(port->m_hComm, &dwError, &comstat);

			if (comstat.cbInQue == 0)
				continue;
		}	// end if bResult

		// Main wait function.  This function will normally block the thread
		// until one of nine events occur that require action.
		Event = WaitForMultipleObjects(3, port->m_hEventArray, FALSE, INFINITE);

		switch (Event)
		{
		case 0:
			{
				// Shutdown event.  This is event zero so it will be
				// the higest priority and be serviced first.
				CloseHandle(port->m_hComm);
				port->m_hComm=NULL;
				port->m_bThreadAlive = FALSE;
				
				// Kill this thread.  break is not needed, but makes me feel better.
				AfxEndThread(100);

				break;
			}
		case 1:	// read event
			{
				GetCommMask(port->m_hComm, &CommEvent);
				if (CommEvent & EV_RXCHAR)
					// Receive character event from port.
					ReceiveChar(port, comstat);
					
				break;
			}  
		case 2: // write event
			{
				// Write character event from port
				WriteChar(port);
				break;
			}

		} // end switch

	} // close forever loop

	return 0;
}
void CMySerial::WriteToPort(char* string)
{		
	assert(m_hComm != 0);
	
	memset(m_szWriteBuffer, 0, sizeof(m_szWriteBuffer));
	strcpy(m_szWriteBuffer, string);
	m_nWriteSize=strlen(string);

	SetEvent(m_hWriteEvent);
}


void CMySerial::WriteToPort(char* string,int n)
{		
	assert(m_hComm != 0);

	memset(m_szWriteBuffer, 0, sizeof(m_szWriteBuffer));
	memcpy(m_szWriteBuffer, string, n);
	m_nWriteSize=n;

	SetEvent(m_hWriteEvent);
}

void CMySerial::WriteToPort(LPCTSTR string)
{		
	assert(m_hComm != 0);

	memset(m_szWriteBuffer, 0, sizeof(m_szWriteBuffer));
	strcpy(m_szWriteBuffer, string);
	m_nWriteSize=strlen(string);

	SetEvent(m_hWriteEvent);
}

void CMySerial::WriteToPort(LPCTSTR string,int n)
{		
	assert(m_hComm != 0);

	memset(m_szWriteBuffer, 0, sizeof(m_szWriteBuffer));
	memcpy(m_szWriteBuffer, string, n);
	m_nWriteSize=n;

	SetEvent(m_hWriteEvent);
}

//
// Return the device control block
//
DCB CMySerial::GetDCB()
{
	return m_dcb;
}

//
// Return the communication event masks
//
DWORD CMySerial::GetCommEvents()
{
	return m_dwCommEvents;
}

//
// Return the output buffer size
//
DWORD CMySerial::GetWriteBufferSize()
{
	return m_nWriteBufferSize;
}


void CMySerial::ClosePort()
{
	SetEvent(m_hShutdownEvent);
}
void CMySerial::WriteChar(CMySerial* port)
{
	BOOL bWrite = TRUE;
	BOOL bResult = TRUE;

	DWORD BytesSent = 0;

	ResetEvent(port->m_hWriteEvent);

	// 获取m_csCommunicationSync的所有权
	EnterCriticalSection(&port->m_csCommunicationSync);

	if (bWrite)
	{
		// Initailize variables
		port->m_ov.Offset = 0;
		port->m_ov.OffsetHigh = 0;

		// Clear buffer
		PurgeComm(port->m_hComm, PURGE_RXCLEAR | PURGE_TXCLEAR | PURGE_RXABORT | PURGE_TXABORT);

		bResult = WriteFile(port->m_hComm,							// Handle to COMM Port
							port->m_szWriteBuffer,					// Pointer to message buffer in calling finction
//							strlen((char*)port->m_szWriteBuffer),	// Length of message to send
							port->m_nWriteSize,	// Length of message to send
							&BytesSent,								// Where to store the number of bytes sent
							&port->m_ov);							// Overlapped structure

		// deal with any error codes
		if (!bResult)  
		{
			DWORD dwError = GetLastError();
			switch (dwError)
			{
				case ERROR_IO_PENDING:
					{
						// continue to GetOverlappedResults()
						BytesSent = 0;
						bWrite = FALSE;
						break;
					}
				default:
					{
						// all other error codes
						port->ProcessErrorMessage("WriteFile()");
					}
			}
		} 
		else
		{
			LeaveCriticalSection(&port->m_csCommunicationSync);
		}
	} // end if(bWrite)

	if (!bWrite)
	{
		bWrite = TRUE;
	
		bResult = GetOverlappedResult(port->m_hComm,	// Handle to COMM port 
									  &port->m_ov,		// Overlapped structure
									  &BytesSent,		// Stores number of bytes sent
									  TRUE); 			// Wait flag

		LeaveCriticalSection(&port->m_csCommunicationSync);

		// deal with the error code 
		if (!bResult)  
		{
			port->ProcessErrorMessage("GetOverlappedResults() in WriteFile()");
		}	
	} 

	//Verify that the data size send equals what we tried to send
	if (BytesSent != port->m_nWriteSize)	// Length of message to send)
	{
		TRACE("WARNING: WriteFile() error.. Bytes Sent: %d; Message Length: %d\n", BytesSent, strlen((char*)port->m_szWriteBuffer));
	}
}
BOOL CMySerial::StartMonitoring()
{
	if (!(m_Thread = AfxBeginThread(CommThread, this)))
		return FALSE;
	TRACE("Thread started\n");
	return TRUE;	
}

//
// Restart the comm thread
//
BOOL CMySerial::RestartMonitoring()
{
	TRACE("Thread resumed\n");
	m_Thread->ResumeThread();
	return TRUE;	
}


//
// Suspend the comm thread
//
BOOL CMySerial::StopMonitoring()
{
	TRACE("Thread suspended\n");
	m_Thread->SuspendThread(); 
	return TRUE;	
}