//download from http://blog.csdn.net/bmbm546/article/details/5740707

//头文件.h


#ifndef __SERIALPORT_H__
#define __SERIALPORT_H__

#define WM_COMM_BREAK_DETECTED  WM_USER+1 // A break was detected on input.
#define WM_COMM_CTS_DETECTED  WM_USER+2 // The CTS (clear-to-send) signal changed state. 
#define WM_COMM_DSR_DETECTED  WM_USER+3 // The DSR (data-set-ready) signal changed state. 
#define WM_COMM_ERR_DETECTED  WM_USER+4 // A line-status error occurred. Line-status errors are CE_FRAME, CE_OVERRUN, and CE_RXPARITY. 
#define WM_COMM_RING_DETECTED  WM_USER+5 // A ring indicator was detected. 
#define WM_COMM_RLSD_DETECTED  WM_USER+6 // The RLSD (receive-line-signal-detect) signal changed state. 
#define WM_COMM_RXCHAR    WM_USER+7 // A character was received and placed in the input buffer. 
#define WM_COMM_RXFLAG_DETECTED  WM_USER+8 // The event character was received and placed in the input buffer.  
#define WM_COMM_TXEMPTY_DETECTED WM_USER+9 // The last character in the output buffer was sent.  

class CSerialPort
{               
public:
 int m_nWriteSize;
 void ClosePort();
 // contruction and destruction
 CSerialPort();
 virtual  ~CSerialPort();

 // port initialisation           
 BOOL  InitPort(CWnd* pPortOwner, UINT portnr = 1, UINT baud = 19200, char parity = ''N'', UINT databits = 8, UINT stopbits = 1, DWORD dwCommEvents = EV_RXCHAR, UINT writebuffersize = 1024);
 HANDLE    m_hComm;

 // start/stop comm watching
 BOOL  StartMonitoring();
 BOOL  RestartMonitoring();
 BOOL  StopMonitoring();

 DWORD  GetWriteBufferSize();
 DWORD  GetCommEvents();
 DCB   GetDCB();

 void  WriteToPort(char* string);
 void  WriteToPort(char* string,int n);
 void  WriteToPort(LPCTSTR string);
 void  WriteToPort(LPCTSTR string,int n);

protected:
 // protected memberfunctions
 void  ProcessErrorMessage(char* ErrorText);
 static UINT CommThread(LPVOID pParam);
 static void ReceiveChar(CSerialPort* port, COMSTAT comstat);
 static void WriteChar(CSerialPort* port);

 // thread
 CWinThread*   m_Thread;

 // synchronisation objects
 CRITICAL_SECTION m_csCommunicationSync;
 BOOL    m_bThreadAlive;

 // handles
 HANDLE    m_hWriteEvent;
 HANDLE    m_hShutdownEvent;

 // Event array. 
 // One element is used for each event. There are two event handles for each port.
 // A Write event and a receive character event which is located in the overlapped structure (m_ov.hEvent).
 // There is a general shutdown when the port is closed. 
 HANDLE    m_hEventArray[3];

 // structures
 OVERLAPPED   m_ov;
 COMMTIMEOUTS  m_CommTimeouts;
 DCB     m_dcb;

 // owner window
 CWnd*    m_pOwner;

 // misc
 UINT    m_nPortNr;
 char*    m_szWriteBuffer;
 DWORD    m_dwCommEvents;
 DWORD    m_nWriteBufferSize;
};

#endif __SERIALPORT_H__


 

// 程序文件C++文件.cpp

 

#include "stdafx.h"
#include "SerialPort.h"

#include <assert.h>

 
//
// Constructor
//
CSerialPort::CSerialPort()
{
 m_hComm = NULL;

 // initialize overlapped structure members to zero
 m_ov.Offset = 0;
 m_ov.OffsetHigh = 0;

 // create events
 m_ov.hEvent = NULL;
 m_hWriteEvent = NULL;
 m_hShutdownEvent = NULL;

 m_szWriteBuffer = NULL;
 m_nWriteSize=1;

 m_bThreadAlive = FALSE;
}

//
// Delete dynamic memory
//
CSerialPort::~CSerialPort()
{
 do
 {
  SetEvent(m_hShutdownEvent);
 } while (m_bThreadAlive);


 TRACE("Thread ended/n");

 delete [] m_szWriteBuffer;
}

//
// Initialize the port. This can be port 1 to 4.
//
BOOL CSerialPort::InitPort(CWnd* pPortOwner, // the owner (CWnd) of the port (receives message)
         UINT  portnr,  // portnumber (1..4)
         UINT  baud,   // baudrate
         char  parity,  // parity 
         UINT  databits,  // databits 
         UINT  stopbits,  // stopbits 
         DWORD dwCommEvents, // EV_RXCHAR, EV_CTS etc
         UINT  writebuffersize) // size to the writebuffer
{
 assert(portnr > 0 && portnr < 5);
 assert(pPortOwner != NULL);

 // if the thread is alive: Kill
 if (m_bThreadAlive)
 {
  do
  {
   SetEvent(m_hShutdownEvent);
  } while (m_bThreadAlive);
  TRACE("Thread ended/n");
 }

 // create events
 if (m_ov.hEvent != NULL)
  ResetEvent(m_ov.hEvent);
 m_ov.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);

 if (m_hWriteEvent != NULL)
  ResetEvent(m_hWriteEvent);
 m_hWriteEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
 
 if (m_hShutdownEvent != NULL)
  ResetEvent(m_hShutdownEvent);
 m_hShutdownEvent = CreateEvent(NULL, TRUE, FALSE, NULL);

 // initialize the event objects
 m_hEventArray[0] = m_hShutdownEvent; // highest priority
 m_hEventArray[1] = m_ov.hEvent;
 m_hEventArray[2] = m_hWriteEvent;

 // initialize critical section
 InitializeCriticalSection(&m_csCommunicationSync);
 
 // set buffersize for writing and save the owner
 m_pOwner = pPortOwner;

 if (m_szWriteBuffer != NULL)
  delete [] m_szWriteBuffer;
 m_szWriteBuffer = new char[writebuffersize];

 m_nPortNr = portnr;

 m_nWriteBufferSize = writebuffersize;
 m_dwCommEvents = dwCommEvents;

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

 // now it critical!
 EnterCriticalSection(&m_csCommunicationSync);

 // if the port is already opened: close it
 if (m_hComm != NULL)
 {
  CloseHandle(m_hComm);
  m_hComm = NULL;
 }

 // prepare port strings
 sprintf(szPort, "COM%d", portnr);
 sprintf(szBaud, "baud=%d parity=%c data=%d stop=%d", baud, parity, databits, stopbits);

 // get a handle to the port
 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
          0);       // template must be 0 for comm devices

 if (m_hComm == INVALID_HANDLE_VALUE)
 {
  // port not found
  delete [] szPort;
  delete [] szBaud;

  return FALSE;
 }

 // set the timeout values
 m_CommTimeouts.ReadIntervalTimeout = 1000;
 m_CommTimeouts.ReadTotalTimeoutMultiplier = 1000;
 m_CommTimeouts.ReadTotalTimeoutConstant = 1000;
 m_CommTimeouts.WriteTotalTimeoutMultiplier = 1000;
 m_CommTimeouts.WriteTotalTimeoutConstant = 1000;

 // configure
 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;  // set RTS bit high!
    if (BuildCommDCB(szBaud, &m_dcb))
    {
     if (SetCommState(m_hComm, &m_dcb))
      ; // normal operation... continue
     else
      ProcessErrorMessage("SetCommState()");
    }
    else
     ProcessErrorMessage("BuildCommDCB()");
   }
   else
    ProcessErrorMessage("GetCommState()");
  }
  else
   ProcessErrorMessage("SetCommMask()");
 }
 else
  ProcessErrorMessage("SetCommTimeouts()");

 delete [] szPort;
 delete [] szBaud;

 // flush the port
 PurgeComm(m_hComm, PURGE_RXCLEAR | PURGE_TXCLEAR | PURGE_RXABORT | PURGE_TXABORT);

 // release critical section
 LeaveCriticalSection(&m_csCommunicationSync);

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

 return TRUE;
}

//
//  The CommThread Function.
//
UINT CSerialPort::CommThread(LPVOID pParam)
{
 // Cast the void pointer passed to the thread back to
 // a pointer of CSerialPort class
 CSerialPort *port = (CSerialPort*)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);
    if (CommEvent & EV_CTS)
     ::SendMessage(port->m_pOwner->m_hWnd, WM_COMM_CTS_DETECTED, (WPARAM) 0, (LPARAM) port->m_nPortNr);
    if (CommEvent & EV_BREAK)
     ::SendMessage(port->m_pOwner->m_hWnd, WM_COMM_BREAK_DETECTED, (WPARAM) 0, (LPARAM) port->m_nPortNr);
    if (CommEvent & EV_ERR)
     ::SendMessage(port->m_pOwner->m_hWnd, WM_COMM_ERR_DETECTED, (WPARAM) 0, (LPARAM) port->m_nPortNr);
    if (CommEvent & EV_RING)
     ::SendMessage(port->m_pOwner->m_hWnd, WM_COMM_RING_DETECTED, (WPARAM) 0, (LPARAM) port->m_nPortNr);
    
    if (CommEvent & EV_RXFLAG)
     ::SendMessage(port->m_pOwner->m_hWnd, WM_COMM_RXFLAG_DETECTED, (WPARAM) 0, (LPARAM) port->m_nPortNr);
     
    break;
   }  
  case 2: // write event
   {
    // Write character event from port
    WriteChar(port);
    break;
   }

  } // end switch

 } // close forever loop

 return 0;
}

//
// start comm watching
//
BOOL CSerialPort::StartMonitoring()
{
 if (!(m_Thread = AfxBeginThread(CommThread, this)))
  return FALSE;
 TRACE("Thread started/n");
 return TRUE; 
}

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


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


//
// If there is a error, give the right message
//
void CSerialPort::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;
}

//
// Write a character.
//
void CSerialPort::WriteChar(CSerialPort* port)
{
 BOOL bWrite = TRUE;
 BOOL bResult = TRUE;

 DWORD BytesSent = 0;

 ResetEvent(port->m_hWriteEvent);

 // 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
       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()");
  } 
 } // end if (!bWrite)

 // Verify that the data size send equals what we tried to send
// if (BytesSent != strlen((char*)port->m_szWriteBuffer))
 {
//  TRACE("WARNING: WriteFile() error.. Bytes Sent: %d; Message Length: %d/n", BytesSent, strlen((char*)port->m_szWriteBuffer));
 }
// ::SendMessage((port->m_pOwner)->m_hWnd, WM_COMM_TXEMPTY_DETECTED, (WPARAM) RXBuff, (LPARAM) port->m_nPortNr);
 ::SendMessage((port->m_pOwner)->m_hWnd, WM_COMM_TXEMPTY_DETECTED,0,(LPARAM) port->m_nPortNr);

}

//
// Character received. Inform the owner
//
void CSerialPort::ReceiveChar(CSerialPort* 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_pOwner)->m_hWnd, WM_COMM_RXCHAR, (WPARAM) RXBuff, (LPARAM) port->m_nPortNr);
 } // end forever loop

}

//
// Write a string to the port
//
void CSerialPort::WriteToPort(char* string)
{  
 assert(m_hComm != 0);
 
 memset(m_szWriteBuffer, 0, sizeof(m_szWriteBuffer));
 strcpy(m_szWriteBuffer, string);
 m_nWriteSize=strlen(string);

 // set event for write
 SetEvent(m_hWriteEvent);
}


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

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

 // set event for write
 SetEvent(m_hWriteEvent);
}

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

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

 // set event for write
 SetEvent(m_hWriteEvent);
}

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

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

 // set event for write
 SetEvent(m_hWriteEvent);
}

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

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

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


void CSerialPort::ClosePort()
{
 SetEvent(m_hShutdownEvent);
}