SerialPort.h SerialPort.cpp

SerialPort.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:
    // contruction and destruction
    CSerialPort();                   // 构造函数
    virtual        ~CSerialPort();  //析构函数虚拟化了，是为了不同端口对象被消灭的时候，可以进行不同的收尾工作

    // port initialisation                                            
    BOOL        InitPort(CWnd* pPortOwner, UINT portnr = 1, UINT baud = 19200,           
                char parity = 'N', UINT databits = 8, UINT stopsbits = 1, 
                DWORD dwCommEvents = EV_RXCHAR | EV_CTS, UINT nBufferSize = 512,
            
                DWORD ReadIntervalTimeout = 1000,
                DWORD ReadTotalTimeoutMultiplier = 1000,
                DWORD ReadTotalTimeoutConstant = 1000,
                DWORD WriteTotalTimeoutMultiplier = 1000,
                DWORD WriteTotalTimeoutConstant = 1000);

    // 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); // add by mrlong 2007-12-25
    void        WriteToPort(LPCTSTR string);     // add by mrlong 2007-12-25
    void        WriteToPort(BYTE* Buffer, int n);// add by mrlong
    void        ClosePort();                     // add by mrlong 2007-12-2  

    void SendData(LPCTSTR lpszData, const int nLength);   //串口发送函数 by mrlong 2008-2-15
    BOOL RecvData(LPTSTR lpszData, const int nSize);      //串口接收函数 by mrlong 2008-2-15

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_hShutdownEvent;  //stop发生的事件
    HANDLE                m_hComm;           // read  
    HANDLE                m_hWriteEvent;     // write
    
    // 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;
    
    int                 m_nWriteSize; //add by mrlong 2007-12-25
};

#endif __SERIALPORT_H__

SerialPort.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_bThreadAlive = FALSE;
    m_nWriteSize = 1;
}

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

    if (m_hComm != NULL)
    {
        CloseHandle(m_hComm);
        m_hComm = NULL;
    }
    // Close Handles  
    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
");

    delete [] m_szWriteBuffer;
}

//
// Initialize the port. This can be port 1 to 4.
//
//
//parity:
//  n=none
//  e=even
//  o=odd
//  m=mark
//  s=space
//data:
//  5,6,7,8
//stop:
//  1,1.5,2 
//
BOOL CSerialPort::InitPort(CWnd* pPortOwner,    // the owner (CWnd) of the port (receives message)
                           UINT  portnr,        
                           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
                           
                           DWORD   ReadIntervalTimeout,
                           DWORD   ReadTotalTimeoutMultiplier,
                           DWORD   ReadTotalTimeoutConstant,
                           DWORD   WriteTotalTimeoutMultiplier,
                           DWORD   WriteTotalTimeoutConstant )    

{
    //assert(portnr > 0 && portnr < 5);//Del by wl 20120612
    assert(pPortOwner != NULL);

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

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

    if (m_hWriteEvent != NULL)
        ResetEvent(m_hWriteEvent);
    else
        m_hWriteEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
    
    if (m_hShutdownEvent != NULL)
        ResetEvent(m_hShutdownEvent);
    else
        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);
    // stop is index 0 = 1 1=1.5 2=2
    int mystop;
    int myparity;
    switch(stopbits)
    {
        case 0:
            mystop = ONESTOPBIT;
            break;
        case 1:
            mystop = ONE5STOPBITS;
            break;
        case 2:
            mystop = TWOSTOPBITS;
            break;
    }
    myparity = 0;
    switch(parity)
    {
        case 'N':
            myparity = 0;
            break;
        case 'E':
            myparity = 1;
            break;
        case 'O':
            myparity = 2;
            break;
        case 'M':
            myparity = 3;
            break;
        case 'S':
            myparity = 4;
            break;
    }
    sprintf(szBaud, "baud=%d parity=%c data=%d stop=%d", baud, parity, databits, mystop);

    // 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         = ReadIntervalTimeout * 1000;
    m_CommTimeouts.ReadTotalTimeoutMultiplier  = ReadTotalTimeoutMultiplier * 1000;
    m_CommTimeouts.ReadTotalTimeoutConstant    = ReadTotalTimeoutConstant * 1000;
    m_CommTimeouts.WriteTotalTimeoutMultiplier = WriteTotalTimeoutMultiplier * 1000;
    m_CommTimeouts.WriteTotalTimeoutConstant   = 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!
                m_dcb.BaudRate = baud;  // add by mrlong
                m_dcb.Parity   = myparity;
                m_dcb.ByteSize = databits;
                m_dcb.StopBits = mystop;
                        
                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.
Use Startmonitor to communicate.
", 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.

                 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);
                memset(&comstat, 0, sizeof(COMSTAT));
                if (CommEvent & EV_RXCHAR) //接收到字符，并置于输入缓冲区中 
                    ReceiveChar(port, comstat);
                
                if (CommEvent & EV_CTS) //CTS信号状态发生变化
                    ::SendMessage(port->m_pOwner->m_hWnd, WM_COMM_CTS_DETECTED, (WPARAM) 0, (LPARAM) port->m_nPortNr);
                if (CommEvent & EV_RXFLAG) //接收到事件字符，并置于输入缓冲区中 
                    ::SendMessage(port->m_pOwner->m_hWnd, WM_COMM_RXFLAG_DETECTED, (WPARAM) 0, (LPARAM) port->m_nPortNr);
                if (CommEvent & EV_BREAK)  //输入中发生中断
                    ::SendMessage(port->m_pOwner->m_hWnd, WM_COMM_BREAK_DETECTED, (WPARAM) 0, (LPARAM) port->m_nPortNr);
                if (CommEvent & EV_ERR) //发生线路状态错误，线路状态错误包括CE_FRAME,CE_OVERRUN和CE_RXPARITY 
                    ::SendMessage(port->m_pOwner->m_hWnd, WM_COMM_ERR_DETECTED, (WPARAM) 0, (LPARAM) port->m_nPortNr);
                if (CommEvent & EV_RING) //检测到振铃指示
                    ::SendMessage(port->m_pOwner->m_hWnd, WM_COMM_RING_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
");
    return TRUE;    
}
//
// Restart the comm thread
//
BOOL CSerialPort::RestartMonitoring()
{
    TRACE("Thread resumed
");
    m_Thread->ResumeThread();
    return TRUE;    
}


//
// Suspend the comm thread
//
BOOL CSerialPort::StopMonitoring()
{
    TRACE("Thread suspended
");
    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: 
%s
Port: %d
", (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;
    DWORD SendLen   = port->m_nWriteSize;
    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
                            SendLen,    // add by mrlong
                            //strlen((char*)port->m_szWriteBuffer),    // 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 != SendLen /*strlen((char*)port->m_szWriteBuffer)*/)  // add by 
    {
        TRACE("WARNING: WriteFile() error.. Bytes Sent: %d; Message Length: %d
", BytesSent, strlen((char*)port->m_szWriteBuffer));
    }
}

//
// 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 (;;) 
    { 
       //add by liquanhai  防止死锁
       if(WaitForSingleObject(port->m_hShutdownEvent,0)==WAIT_OBJECT_0)
        return;

        // 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);
        
        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); // add by mrlong
    // 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()
{
    MSG message;  
    do
    {
        SetEvent(m_hShutdownEvent);
        if(::PeekMessage(&message,m_pOwner->m_hWnd,0,0,PM_REMOVE))
        {
            ::TranslateMessage(&message);
            ::DispatchMessage(&message);
        }
               
    } while (m_bThreadAlive);

    // if the port is still opened: close it 
    if (m_hComm != NULL)
    {
        CloseHandle(m_hComm);
        m_hComm = NULL;
    }
    
    // Close Handles  
    if(m_hShutdownEvent!=NULL)
        ResetEvent(m_hShutdownEvent);
    if(m_ov.hEvent!=NULL)
        ResetEvent(m_ov.hEvent);
    if(m_hWriteEvent!=NULL)
        ResetEvent(m_hWriteEvent);            
        
    //delete [] m_szWriteBuffer;
    
}

void CSerialPort::WriteToPort(char* string,int n)
{
    assert(m_hComm != 0);
    memset(m_szWriteBuffer, 0, sizeof(m_szWriteBuffer));
    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(BYTE* Buffer, int n)
{
    assert(m_hComm != 0);
    memset(m_szWriteBuffer, 0, sizeof(m_szWriteBuffer));//清零
    int i;
    for(i=0; i<n; i++)
    {
        m_szWriteBuffer[i] = Buffer[i];//读缓存
    }
    m_nWriteSize=n;

    // set event for write
    SetEvent(m_hWriteEvent);//SetEvent/ResetEvent分别将EVENT置为这两种状态分别是发信号与不发信号
}


void CSerialPort::SendData(LPCTSTR lpszData, const int nLength)
{
    assert(m_hComm != 0);
    memset(m_szWriteBuffer, 0, nLength);
    strcpy(m_szWriteBuffer, lpszData);
    m_nWriteSize=nLength;
    // set event for write
    SetEvent(m_hWriteEvent);
}

BOOL CSerialPort::RecvData(LPTSTR lpszData, const int nSize)
{
    //
    //接收数据
    //
    assert(m_hComm!=0);
    memset(lpszData,0,nSize);
    DWORD mylen  = 0;
    DWORD mylen2 = 0;
    while (mylen<nSize) {
        if(!ReadFile(m_hComm,lpszData,nSize,&mylen2,NULL)) 
            return FALSE;
        mylen += mylen2;

        
    }
    
    return TRUE;
}