串口类的编写

CSerial类只有2个文件，分别是CSerial.cpp和CSerial.h。

CSerial.h内容如下：

/***************************************************
 *作    者:温子祺
 *联系方式:wenziqi@hotmail.com
 *说    明:CSerial.h
           提供外部调用的函数
           Open(),Close(),Send()
           接收数据时通过消息来实现
 ***************************************************/
#ifndef __CSERIAL_H__
 #define __CSERIAL_H__
 #pragma once

 class CSerial
{
 public:
            CSerial(void);
    virtual~CSerial(void);

    BOOL Open(CWnd *pPortOwner,
              UINT  portnr,
              UINT  baud,
              UINT  parity,
              UINT  databits,
              UINT  stopbits,
              UINT  rxdmsg);

    BOOL Close(void);

    UINT Send(UCHAR *pbuf,UINT len);

 protected:

    BOOL  Ready(void) const;
    BOOL  CreateThreadAndEvent(void);
 static
    DWORD RecvThread(LPVOID lpArg);

private:
    CWnd *  m_pOwner;
    BOOL    m_bInit;

    HANDLE  m_hSerial;
    HANDLE  m_hRecvEvent;
    HANDLE  m_hRecvExitEvent;

    UINT    m_unRxdMsg;
};
#endif

CSerial.cpp代码如下：

/***************************************************
 *作    者:温子祺
 *联系方式:wenziqi@hotmail.com
 *说    明:CSerial.cpp
           提供外部调用的函数
           Open(),Close(),Send()
           接收数据时通过消息来实现
 ***************************************************/
#include "StdAfx.h"
#include "CSerial.h"
#include <assert.h>            //使用断言

CSerial::CSerial(void)       
{
    m_pOwner=NULL;
    m_bInit=FALSE;
    m_hRecvEvent=NULL;
    m_hRecvExitEvent=NULL;
    m_hSerial=NULL;
    m_bInit=FALSE;
}

CSerial::~CSerial(void)
{
    Close();
}

BOOL CSerial::Ready(void)const
{
     return m_bInit;
}

BOOL CSerial::Close(void)
{

    if (m_hSerial)
    {    
        CloseHandle(m_hSerial);
        m_hSerial=NULL;
    }

    if (m_hRecvEvent)
    {
        CloseHandle(m_hRecvEvent);
        m_hRecvEvent=NULL;
    }

    if (m_hRecvExitEvent)
    {
        SetEvent(m_hRecvExitEvent);    //退出线程
        Sleep(10);
        CloseHandle(m_hRecvExitEvent);
        m_hRecvExitEvent=NULL;
    }

    if (m_bInit)
    {
        m_bInit=FALSE;
    }

    if (m_pOwner)
    {
        m_pOwner=NULL;
    }

    return TRUE;
}

BOOL CSerial::Open(CWnd *pPortOwner,
                   UINT  portnr, 
                   UINT  baud, 
                   UINT  parity, 
                   UINT  databits, 
                   UINT  stopbits,
                   UINT  rxdmsg)
{
     assert(NULL != pPortOwner);

     m_pOwner  = pPortOwner;

     if (Ready())
     {
         Close();
     }

     COMMTIMEOUTS CommTimeOuts;
     DCB dcb;

     LPSTR   sz= new  CHAR[64];
     LPWSTR wsz= new WCHAR[64];

     // 打开串口
     //wprintf_s(wsz,64,"COM%d",portnr);//用wprintf无效
     sprintf_s(sz,64,"COM%d",portnr);
     MultiByteToWideChar(CP_ACP,
                         0,
                         sz,
                         64,
                         wsz,
                         64);
    
     m_hSerial = CreateFile(wsz, 
                            GENERIC_READ | GENERIC_WRITE,
                            0, 
                            0, 
                            OPEN_EXISTING, 
                            0, 
                            0);
     
     delete []sz;
     delete []wsz;
    
     if(m_hSerial == INVALID_HANDLE_VALUE)
     {
         return FALSE;
     }

     GetCommState(m_hSerial, &dcb);                        /* 读取串口的DCB */
     dcb.BaudRate = baud;                                //波特率        
     dcb.ByteSize = databits;                           //数据位
     dcb.Parity   = parity;                               //校验位
     dcb.StopBits = stopbits;                            //停止位

     dcb.fParity = FALSE;                                /* 禁止奇偶校验 */
     dcb.fBinary = TRUE;
     dcb.fDtrControl = 0;                                /* 禁止流量控制 */
     dcb.fRtsControl = 0;
     dcb.fOutX = 0;
     dcb.fInX = 0;
     dcb.fTXContinueOnXoff = 0;
     dcb.EvtChar='q';                                    // 这个一定要,否则大于127的数值会接收不了啊
     
     //设置状态参数
     SetCommMask(m_hSerial, EV_RXFLAG|EV_RXCHAR);                    /* 串口事件:接收到一个字符 */    
     SetupComm(m_hSerial, 1024, 1024);                /* 设置接收与发送的缓冲区大小 */
     
     if(!SetCommState(m_hSerial, &dcb))                    /* 设置串口的DCB */
     {
         return FALSE;
     }

     //设置超时参数
     GetCommTimeouts(m_hSerial, &CommTimeOuts);        
     CommTimeOuts.ReadIntervalTimeout = 100;                /* 接收字符间最大时间间隔 */
     CommTimeOuts.ReadTotalTimeoutMultiplier = 1;        
     CommTimeOuts.ReadTotalTimeoutConstant = 100;            /* 读数据总超时常量 */
     CommTimeOuts.WriteTotalTimeoutMultiplier = 0;
     CommTimeOuts.WriteTotalTimeoutConstant = 0;    

     if(!SetCommTimeouts(m_hSerial, &CommTimeOuts))
     {
         return FALSE;
     }

     PurgeComm(m_hSerial, PURGE_RXCLEAR | PURGE_TXCLEAR | PURGE_RXABORT | PURGE_TXABORT);     /* 清除收/发缓冲区 */

     if (!CreateThreadAndEvent())
     {
         return FALSE;
     }

     m_unRxdMsg=rxdmsg;

     m_bInit = TRUE;

     return TRUE;
}
BOOL CSerial::CreateThreadAndEvent(void)
{
    m_hRecvExitEvent = CreateEvent(NULL, TRUE, FALSE, NULL);        /* 创建串口接收线程退出事件*/

    if (NULL==m_hRecvExitEvent)
    {
        return FALSE;
    }

    ResetEvent(m_hRecvExitEvent);                                    //设置线程没有退出

    HANDLE hRecvThread=NULL;
    DWORD  dwThreadID =0;

    // 创建串口接收线程
    hRecvThread=CreateThread(0, 
                             0, 
     (LPTHREAD_START_ROUTINE)RecvThread, 
                             this, 
                             0, 
                             &dwThreadID);

    if (NULL==hRecvThread)
    {
        return FALSE;
    }

    CloseHandle(hRecvThread);
    hRecvThread=NULL;    

    return TRUE;
}

UINT CSerial::Send(UCHAR *pbuf,UINT len)
{
    if (!Ready())
    {
        //AfxMessageBox(_T("请确保串口已正常打开"));
        return 0;
    }

    BOOL rt=FALSE;

    DWORD dwBytesSend=0,dwCnt=0;

    while (len>dwCnt)
    {
       rt=WriteFile(m_hSerial,pbuf+dwCnt,len-dwCnt,&dwBytesSend,NULL);

       if (!rt)
       {
           return FALSE;
       }

       dwCnt+=dwBytesSend;

       if (len > dwCnt)
       {
           Sleep(100); //有可能I/O挂起
       }
    }

    return (UINT)dwCnt;
}

DWORD CSerial::RecvThread(LPVOID lpArg)
{

    assert(NULL != lpArg);

    CSerial *pArg=(CSerial *)lpArg;

    assert(NULL != pArg);

    DWORD   dwBytesRecv=0;
    DWORD   dwError=0;
    UCHAR   ucDat=0;
    COMSTAT ComStat;

    memset(&ComStat,0,sizeof(ComStat));

    while (1)
    {
        if (WaitForSingleObject(pArg->m_hRecvExitEvent,0)==WAIT_OBJECT_0)
        {
            break; //线程退出
        }

        if (pArg->Ready())
        {
            ClearCommError(pArg->m_hSerial,&dwError,&ComStat);

            if (0 == ComStat.cbInQue)
            {
                Sleep(1);
                continue;
            }

            if (ReadFile(pArg->m_hSerial,&ucDat,1,&dwBytesRecv,NULL))
            {
                if (dwBytesRecv)
                {
                  ::SendMessage((pArg->m_pOwner)->m_hWnd,
                                 pArg->m_unRxdMsg,
                         (WPARAM)ucDat,
                                 NULL);
                }
            }
        }

        Sleep(1);
        
    }

    Sleep(10);  //让线程安全退出

    return 0;
}