serialport.cpp

很好用的串口类

	);

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

	LocalFree(lpMsgBuf);
}

//
// Character received. Inform the owner
//
void CSerialPortEx::ReceiveChar(CSerialPortEx* port, COMSTAT comstat)
{
	BOOL  bRead = TRUE; 
	BOOL  bResult = TRUE;
	DWORD dwError = 0;
	DWORD BytesRead = 0;
	unsigned char RXBuff=0;

	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_Owner, WM_COMM_RXCHAR, (WPARAM) RXBuff, (LPARAM) port->m_nPortNr);
	} // end forever loop		

}

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

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

/*
DWORD CSerialPortEx::ReadCommBlock(unsigned char *string, int nMaxLength)
{
    BOOL       fReadStat ;
	COMSTAT    ComStat ;
    DWORD      dwErrorFlags;
    DWORD      dwLength;
    DWORD      dwError;
 
    // only try to read number of bytes in queue

	EnterCriticalSection(&m_csCommunicationSync);
	dwLength = 0;
	int n = 0;
	while(dwLength < nMaxLength && n < 10)
	{
	  Sleep(10);
      BOOL ok=ClearCommError( m_hComm, &dwErrorFlags, &ComStat ) ;
      dwLength = min( (DWORD) nMaxLength, ComStat.cbInQue ) ;
	  n++;
    }
    if (dwLength > 0)
    {
 	  fReadStat = ReadFile(m_hComm,string,dwLength,&dwLength,&m_ov) ;
       if (!fReadStat)
       {
          if ((dwError=GetLastError()) == ERROR_IO_PENDING)
          {
		     ;
 	      }
          else
          {
             // some other error occurred
             dwLength = 0 ;
             ClearCommError( m_hComm, &dwErrorFlags, &ComStat ) ;
           }
       }
    }
	string[dwLength] = '\0';
	LeaveCriticalSection(&m_csCommunicationSync);
    return dwLength ;
}
*/
DWORD CSerialPortEx::ReadCommBlock(unsigned char *string, int nMaxLength)
{
    BOOL       fReadStat ;
	COMSTAT    ComStat ;
    DWORD      dwErrorFlags;
    DWORD      dwLength;
    DWORD      dwError;
 
    // only try to read number of bytes in queue

	EnterCriticalSection(&m_csCommunicationSync);
	dwLength = 0;
	int n = 0,curr = 0;;
	while(dwLength < nMaxLength && n < 20)
	{
	  Sleep(80);
      BOOL ok=ClearCommError( m_hComm, &dwErrorFlags, &ComStat ) ;
      dwLength = min( (DWORD) nMaxLength, ComStat.cbInQue ) ;
	  n++;
      if (dwLength > 0)
	  {
 	    fReadStat = ReadFile(m_hComm,&string[curr],dwLength,&dwLength,&m_ov) ;
        if (!fReadStat)
        {
          if ((dwError=GetLastError()) == ERROR_IO_PENDING)
          {
		     continue;
 	      }
          else
          {
             // some other error occurred
             dwLength = 0 ;
             ClearCommError( m_hComm, &dwErrorFlags, &ComStat ) ;
           }
        }
		else
		{
			curr += dwLength;
			if(strchr((char *)string,0x03))
				break;
		}
	  }
	}
	string[curr] = '\0';
	LeaveCriticalSection(&m_csCommunicationSync);
    return curr ;
}
//Extension: not tested

BYTE* CSerialPortEx::ReadBlock(CSerialPortEx *port, int& readLen)
{
	COMSTAT comstat;
	BOOL  bRead = TRUE; 
	BOOL  bResult = TRUE;
	DWORD dwError = 0;
	DWORD BytesRead = 0;
	DWORD BytesToRead=readLen;
	BYTE* pRec;

		// Gain ownership of the comm port critical section.
		// This process guarantees no other part of this program 
		// is using the port object.

		// ClearCommError() will update the COMSTAT structure and
		// clear any other errors.
		
		int n = 0;
		do 
		{
			Sleep(10);
			EnterCriticalSection(&port->m_csCommunicationSync);
	        bResult = ClearCommError(port->m_hComm, &dwError, &comstat);
			LeaveCriticalSection(&port->m_csCommunicationSync);
			n++;
	
		} while(comstat.cbInQue != BytesToRead && n < 10);

		// 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 < BytesToRead)
		{
			// break out when all bytes have been read
			readLen=0;
			return NULL;
		}
		else
		{
			BytesToRead= BytesToRead+2 > comstat.cbInQue ? comstat.cbInQue : BytesToRead+2;
			pRec=new BYTE[BytesToRead];
		}

		EnterCriticalSection(&port->m_csCommunicationSync);

		if (bRead)
		{
			bResult = ReadFile(port->m_hComm,		// Handle to COMM port 
							   pRec,				// Reader Buffer Pointer
							   BytesToRead,			// to read bytes
							   &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)

	
		LeaveCriticalSection(&port->m_csCommunicationSync);
		
		readLen=BytesRead;

		return pRec;

		// notify parent that a byte was received
//		::SendMessage((port->m_pOwner)->m_hWnd, WM_COMM_RXCHAR, (WPARAM)pRec, (LPARAM) BytesRead);

}
BOOL CSerialPortEx::WriteBlock(CSerialPortEx *port, BYTE* string, int nLength)
{
	BOOL bWrite = TRUE;
	BOOL bResult = TRUE;
	DWORD dwError = 0;
	DWORD BytesSent = 0;


	// Gain ownership of the critical section
	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
							string,					// Pointer to message buffer in calling finction
							nLength,								// 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)  
		{
			dwError = GetLastError();
			switch (dwError)
			{
				case ERROR_IO_PENDING:
					{
						// continue to GetOverlappedResults()
						BytesSent = 0;
						bWrite = FALSE;
						break;
					}
				default:
					{
						// all other error codes
						port->ProcessErrorMessage("WriteFile()");
					}
			}
		} 
	} // end if(bWrite)
    LeaveCriticalSection(&port->m_csCommunicationSync);
	if (BytesSent != nLength) return FALSE;
	return TRUE;
}

BOOL CSerialPortEx::isopen()
{
	return (m_hComm != NULL && m_hComm != INVALID_HANDLE_VALUE );
}


void CSerialPortEx::Close()
{
	if (m_bThreadAlive)
	{
		do
		{
			SetEvent(m_hShutdownEvent); //关闭线程，用一个事件SetEvent() ，然后在线程内部WaitForMultipleObjects()等待此事件的产生，在线程内部调用AfxEndThread()终止线程。 
			Sleep(1000);                //需要等待一会，然后再重新初始化，否则出错
		} while (m_bThreadAlive);
		TRACE("Thread ended\n");
	}
	if (m_hComm != NULL)
	{
		CloseHandle(m_hComm);
		m_hComm = NULL;
	}
}