深入浅出VC++串口编程之第三方类
2008-10-09 19:26:58 来源：WEB开发网串口类
从本系列文章可以看出，与通过WIN32 API进行串口访问相比，通过MScomm这个Activex控件进行串口访问要来的方便许多，它基本上可以向用户屏蔽多线程的细节，以事件（发出OnComm消息）方式实现串口的异步访问。
尽管如此，MScomm控件的使用仍有诸多不便，譬如其发送和接收数据都要进行VARIANT类型对象与字符串的转化等。因此，国内外许多优秀的程序员自己编写了一些串口类，使用这些类，我们将可以更方便的操作串口。在笔者的《深入浅出Win32多线程程序设计之综合实例》（网址：http://dev.yesky.com）一文中，曾向读者展示了由Remon Spekreijse编写的CSerialPort串口类，而本文将向您展示由程序员llbird编写的cnComm(中国串口？)串口类。
llbird是一位优秀的程序员，他的代码风格简洁而紧凑，类的声明和实现都被定义在一个头文件中，使用这个类的朋友只需要在工程中包含这一头文件即可：
/*
Comm Base Library(WIN98/NT/2000) ver 1.1
Compile by： BC++ 5; C++ BUILDER 4, 5, 6, X; VC++ 5, 6; VC.NET; GCC;
copyright(c) 2004.5 - 2005.8 llbird wushaojian@21cn.com
*/
#ifndef _CN_COMM_H_
#define _CN_COMM_H_
#pragma warning(disable: 4530)
#pragma warning(disable: 4786)
#pragma warning(disable: 4800)
#include <assert.h>
#include <stdio.h>
#include <windows.h>
//送到窗口的消息 WPARAM 端口号
#define ON_COM_RECEIVE WM_USER + 618
#define ON_COM_CTS WM_USER + 619 //LPARAM 1 valid
#define ON_COM_DSR WM_USER + 621 //LPARAM 1 valid
#define ON_COM_RING WM_USER + 623
#define ON_COM_RLSD WM_USER + 624
#define ON_COM_BREAK WM_USER + 625
#define ON_COM_TXEMPTY WM_USER + 626
#define ON_COM_ERROR WM_USER + 627 //LPARAM save Error ID
#define DEFAULT_COM_MASK_EVENT EV_RXCHAR | EV_ERR | EV_CTS | EV_DSR | EV_BREAK | EV_TXEMPTY | EV_RING | EV_RLSD
class cnComm
{
public:
//------------------------------Construction-----------------------------------
//第1个参数为是否在打开串口时启动监视线程， 第2个参数为IO方式 阻塞方式（0）/ 异步重叠方式（默认）
cnComm(bool fAutoBeginThread = true, DWORD dwIOMode =
FILE_FLAG_OVERLAPPED): _dwIOMode(dwIOMode), _fAutoBeginThread(fAutoBeginThread)
{
Init();
}
virtual ~cnComm()
{
Close();
UnInit();
}
//----------------------------------Attributes----------------------------------
//判断串口是否打开
inline bool IsOpen()
{
return _hCommHandle != INVALID_HANDLE_VALUE;
}
//判断串口是否打开
operator bool()
{
return _hCommHandle != INVALID_HANDLE_VALUE;
}
//获得串口句炳
inline HANDLE GetHandle()
{
return _hCommHandle;
}
//获得串口句炳
operator HANDLE()
{
return _hCommHandle;
}
//获得串口参数 DCB
DCB *GetState()
{
return IsOpen() && ::GetCommState(_hCommHandle, &_DCB) == TRUE ?
&_DCB: NULL;
}
//设置串口参数 DCB
bool SetState(DCB *pdcb = NULL)
{
return IsOpen() ? ::SetCommState(_hCommHandle, pdcb == NULL ? &_DCB:pdcb) == TRUE: false;
}
//设置串口参数：波特率，停止位，等 支持设置字符串 "9600, 8, n, 1"
bool SetState(char *szSetStr)
{
if (IsOpen())
{
if (::GetCommState(_hCommHandle, &_DCB) != TRUE)
return false;
if (::BuildCommDCB(szSetStr, &_DCB) != TRUE)
return false;
return ::SetCommState(_hCommHandle, &_DCB) == TRUE;
}
return false;
}
//设置串口参数：波特率，停止位，等
bool SetState(DWORD dwBaudRate, DWORD dwByteSize = 8, DWORD dwParity =
NOPARITY, DWORD dwStopBits = ONESTOPBIT)
{
if (IsOpen())
{
if (::GetCommState(_hCommHandle, &_DCB) != TRUE)
return false;
_DCB.BaudRate = dwBaudRate;
_DCB.ByteSize = (unsigned char)dwByteSize;
_DCB.Parity = (unsigned char)dwParity;
_DCB.StopBits = (unsigned char)dwStopBits;
return ::SetCommState(_hCommHandle, &_DCB) == TRUE;
}
return false;
}
//获得超时结构
LPCOMMTIMEOUTS GetTimeouts(void)
{
return IsOpen() && ::GetCommTimeouts(_hCommHandle, &_CO) == TRUE ?
&_CO: NULL;
}
//设置超时
bool SetTimeouts(LPCOMMTIMEOUTS lpCO)
{
return IsOpen() ? ::SetCommTimeouts(_hCommHandle, lpCO) == TRUE:false;
}
//设置串口的I/O缓冲区大小
bool SetBufferSize(DWORD dwInputSize, DWORD dwOutputSize)
{
return IsOpen() ? ::SetupComm(_hCommHandle, dwInputSize, dwOutputSize)== TRUE: false;
}
//关联消息的窗口句柄
inline void SetWnd(HWND hWnd)
{
assert(::IsWindow(hWnd));
_hNotifyWnd = hWnd;
}
//设定发送通知, 接受字符最小值
inline void SetNotifyNum(DWORD dwNum)
{
_dwNotifyNum = dwNum;
}
//线程是否运行
inline bool IsThreadRunning()
{
return _hThreadHandle != NULL;
}
//获得线程句柄
inline HANDLE GetThread()
{
return _hThreadHandle;
}
//设置要监视的事件， 打开前设置有效
void SetMaskEvent(DWORD dwEvent = DEFAULT_COM_MASK_EVENT)
{
_dwMaskEvent = dwEvent;
}
//获得读缓冲区的字符数
int GetInputSize()
{
COMSTAT Stat;
DWORD dwError;
return ::ClearCommError(_hCommHandle, &dwError, &Stat) == TRUE ? Stat.cbInQue : (DWORD) - 1L;
}
//----------------------------------Operations----------------------------------
//打开串口 缺省 9600, 8, n, 1
bool Open(DWORD dwPort)
{
return Open(dwPort, 9600);
}
//打开串口 缺省 baud_rate, 8, n, 1
bool Open(DWORD dwPort, DWORD dwBaudRate)
{
if (dwPort < 1 || dwPort > 1024)
return false;
BindCommPort(dwPort);
if (!OpenCommPort())
return false;
if (!SetupPort())
return false;
return SetState(dwBaudRate);
}
//打开串口, 使用类似"9600, 8, n, 1"的设置字符串设置串口
bool Open(DWORD dwPort, char *szSetStr)
{
if (dwPort < 1 || dwPort > 1024)
return false;
BindCommPort(dwPort);
if (!OpenCommPort())
return false;
if (!SetupPort())
return false;
return SetState(szSetStr);
}
//读取串口 dwBufferLength个字符到 Buffer 返回实际读到的字符数 可读任意数据
DWORD Read(LPVOID Buffer, DWORD dwBufferLength, DWORD dwWaitTime = 10)
{
if (!IsOpen())
return 0;
COMSTAT Stat;
DWORD dwError;
if (::ClearCommError(_hCommHandle, &dwError, &Stat) && dwError > 0)
{
::PurgeComm(_hCommHandle,PURGE_RXABORT | PURGE_RXCLEAR);
return 0;
}
if (!Stat.cbInQue)
// 缓冲区无数据
return 0;
unsigned long uReadLength = 0;
dwBufferLength = dwBufferLength > Stat.cbInQue ? Stat.cbInQue :dwBufferLength;
if (!::ReadFile(_hCommHandle, Buffer, dwBufferLength, &uReadLength,&_ReadOverlapped))
{
if (::GetLastError() == ERROR_IO_PENDING)
{
WaitForSingleObject(_ReadOverlapped.hEvent, dwWaitTime);
// 结束异步I/O
if (!::GetOverlappedResult(_hCommHandle, &_ReadOverlapped,&uReadLength, false))
{
if (::GetLastError() != ERROR_IO_INCOMPLETE)
uReadLength = 0;
}
}
else
uReadLength = 0;
}
return uReadLength;
}
//读取串口 dwBufferLength - 1 个字符到 szBuffer 返回ANSI C 模式字符串指针 适合一般字符通讯
char *ReadString(char *szBuffer, DWORD dwBufferLength, DWORD dwWaitTime =20)
{
unsigned long uReadLength = Read(szBuffer, dwBufferLength - 1,dwWaitTime);
szBuffer[uReadLength] = '';
return szBuffer;
}
//写串口 可写任意数据 "abcd" or "x0x1x2"
DWORD Write(LPVOID Buffer, DWORD dwBufferLength)
{
if (!IsOpen())
return 0;
DWORD dwError;
if (::ClearCommError(_hCommHandle, &dwError, NULL) && dwError > 0)
::PurgeComm(_hCommHandle, PURGE_TXABORT | PURGE_TXCLEAR);
unsigned long uWriteLength = 0;
if (!::WriteFile(_hCommHandle, Buffer, dwBufferLength, &uWriteLength,&_WriteOverlapped))
if (::GetLastError() != ERROR_IO_PENDING)
uWriteLength = 0;
return uWriteLength;
}
//写串口 写ANSI C 模式字符串指针
DWORD Write(const char *szBuffer)
{
assert(szBuffer);
return Write((void*)szBuffer, strlen(szBuffer));
}
//读串口 同步应用
DWORD ReadSync(LPVOID Buffer, DWORD dwBufferLength)
{
if (!IsOpen())
return 0;
DWORD dwError;
if (::ClearCommError(_hCommHandle, &dwError, NULL) && dwError > 0)
{
::PurgeComm(_hCommHandle,PURGE_RXABORT | PURGE_RXCLEAR);
return 0;
}
DWORD uReadLength = 0;
::ReadFile(_hCommHandle, Buffer, dwBufferLength, &uReadLength, NULL);
return uReadLength;
}
//写串口 同步应用
DWORD WriteSync(LPVOID Buffer, DWORD dwBufferLength)
{
if (!IsOpen())
return 0;
DWORD dwError;
if (::ClearCommError(_hCommHandle, &dwError, NULL) && dwError > 0)
::PurgeComm(_hCommHandle, PURGE_TXABORT | PURGE_TXCLEAR);
unsigned long uWriteLength = 0;
::WriteFile(_hCommHandle, Buffer, dwBufferLength, &uWriteLength, NULL);
return uWriteLength;
}
//写串口 szBuffer 可以输出格式字符串 包含缓冲区长度
DWORD Write(char *szBuffer, DWORD dwBufferLength, char *szFormat, ...)
{
if (!IsOpen())
return 0;
va_list va;
va_start(va, szFormat);
_vsnprintf(szBuffer, dwBufferLength, szFormat, va);
va_end(va);
return Write(szBuffer);
}
//写串口 szBuffer 可以输出格式字符串 不检查缓冲区长度 小心溢出
DWORD Write(char *szBuffer, char *szFormat, ...)
{
if (!IsOpen())
return 0;
va_list va;
va_start(va, szFormat);
vsprintf(szBuffer, szFormat, va);
va_end(va);
return Write(szBuffer);
}
//关闭串口 同时也关闭关联线程
virtual void Close()
{
if (IsOpen())
{
PurgeComm(_hCommHandle, PURGE_TXABORT | PURGE_TXCLEAR);
EndThread();
::CloseHandle(_hCommHandle);
_hCommHandle = INVALID_HANDLE_VALUE;
}
}
//DTR 电平控制
bool SetDTR(bool OnOrOff)
{
return IsOpen() ? EscapeCommFunction(_hCommHandle, OnOrOff ? SETDTR :CLRDTR): false;
}
//RTS 电平控制
bool SetRTS(bool OnOrOff)
{
return IsOpen() ? EscapeCommFunction(_hCommHandle, OnOrOff ? SETRTS :CLRRTS): false;
}
//
bool SetBreak(bool OnOrOff)
{
return IsOpen() ? EscapeCommFunction(_hCommHandle, OnOrOff ? SETBREAK: CLRBREAK): false;
}
//辅助线程控制 建监视线程
bool BeginThread()
{
if (!IsThreadRunning())
{
_fRunFlag = true;
_hThreadHandle = NULL;
DWORD id;
_hThreadHandle = ::CreateThread(NULL, 0, CommThreadProc, this, 0,&id);
return (_hThreadHandle != NULL);
}
return false;
}
//暂停监视线程
inline bool SuspendThread()
{
return IsThreadRunning() ? ::SuspendThread(_hThreadHandle) !=0xFFFFFFFF: false;
}
//恢复监视线程
inline bool ResumeThread()
{
return IsThreadRunning() ? ::ResumeThread(_hThreadHandle) !=0xFFFFFFFF: false;
}
//终止线程
bool EndThread(DWORD dwWaitTime = 100)
{
if (IsThreadRunning())
{
_fRunFlag = false;
::SetCommMask(_hCommHandle, 0);
::SetEvent(_WaitOverlapped.hEvent);
if (::WaitForSingleObject(_hThreadHandle, dwWaitTime) !=WAIT_OBJECT_0)
if (!::TerminateThread(_hThreadHandle, 0))
return false;
::CloseHandle(_hThreadHandle);
::ResetEvent(_WaitOverlapped.hEvent);
_hThreadHandle = NULL;
return true;
}
return false;
}
protected:
volatile DWORD _dwPort; //串口号
volatile HANDLE _hCommHandle; //串口句柄
char _szCommStr[20]; //保存COM1类似的字符串
DCB _DCB; //波特率，停止位，等
COMMTIMEOUTS _CO; //超时结构
DWORD _dwIOMode; // 0 同步 默认 FILE_FLAG_OVERLAPPED重叠I/O异步
OVERLAPPED _ReadOverlapped, _WriteOverlapped; // 重叠I/O
volatile HANDLE _hThreadHandle; //辅助线程
volatile HWND _hNotifyWnd; // 通知窗口
volatile DWORD _dwNotifyNum; //接受多少字节(>=_dwNotifyNum)发送通知消息
volatile DWORD _dwMaskEvent; //监视的事件
volatile bool _fRunFlag; //线程运行循环标志
bool _fAutoBeginThread; //Open() 自动 BeginThread();
OVERLAPPED _WaitOverlapped; //WaitCommEvent use
//初始化
void Init()
{
memset(_szCommStr, 0, 20);
memset(&_DCB, 0, sizeof(_DCB));
_DCB.DCBlength = sizeof(_DCB);
_hCommHandle = INVALID_HANDLE_VALUE;
memset(&_ReadOverlapped, 0, sizeof(_ReadOverlapped));
memset(&_WriteOverlapped, 0, sizeof(_WriteOverlapped));
_ReadOverlapped.hEvent = ::CreateEvent(NULL, true, false, NULL);
assert(_ReadOverlapped.hEvent != INVALID_HANDLE_VALUE);
_WriteOverlapped.hEvent = ::CreateEvent(NULL, true, false, NULL);
assert(_WriteOverlapped.hEvent != INVALID_HANDLE_VALUE);
_hNotifyWnd = NULL;
_dwNotifyNum = 0;
_dwMaskEvent = DEFAULT_COM_MASK_EVENT;
_hThreadHandle = NULL;
memset(&_WaitOverlapped, 0, sizeof(_WaitOverlapped));
_WaitOverlapped.hEvent = ::CreateEvent(NULL, true, false, NULL);
assert(_WaitOverlapped.hEvent != INVALID_HANDLE_VALUE);
}
//析构
void UnInit()
{
if (_ReadOverlapped.hEvent != INVALID_HANDLE_VALUE)
CloseHandle(_ReadOverlapped.hEvent);
if (_WriteOverlapped.hEvent != INVALID_HANDLE_VALUE)
CloseHandle(_WriteOverlapped.hEvent);
if (_WaitOverlapped.hEvent != INVALID_HANDLE_VALUE)
CloseHandle(_WaitOverlapped.hEvent);
}
//绑定串口
void BindCommPort(DWORD dwPort)
{
assert(dwPort >= 1 && dwPort <= 1024);
char p[5];
_dwPort = dwPort;
strcpy(_szCommStr, ".COM");
ltoa(_dwPort, p, 10);
strcat(_szCommStr, p);
}
//打开串口
virtual bool OpenCommPort()
{
if (IsOpen())
Close();
_hCommHandle = ::CreateFile(_szCommStr, GENERIC_READ | GENERIC_WRITE, 0, NULL,
OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | _dwIOMode,NULL);
if (_fAutoBeginThread)
{
if (IsOpen() && BeginThread())
return true;
else
{
Close(); //创建线程失败
return false;
}
}
return IsOpen();
}
//设置串口
virtual bool SetupPort()
{
if (!IsOpen())
return false;
if (!::SetupComm(_hCommHandle, 4096, 4096))
return false;
if (!::GetCommTimeouts(_hCommHandle, &_CO))
return false;
_CO.ReadIntervalTimeout = 0;
_CO.ReadTotalTimeoutMultiplier = 1;
_CO.ReadTotalTimeoutConstant = 1000;
_CO.WriteTotalTimeoutMultiplier = 1;
_CO.WriteTotalTimeoutConstant = 1000;
if (!::SetCommTimeouts(_hCommHandle, &_CO))
return false;
if (!::PurgeComm(_hCommHandle, PURGE_TXABORT | PURGE_RXABORT |PURGE_TXCLEAR | PURGE_RXCLEAR))
return false;
return true;
}
//---------------------------------------threads callback-----------------------------------
//线程收到消息自动调用, 如窗口句柄有效, 送出消息, 包含串口编号， 均为虚函数可以在基层类中扩展
virtual void OnReceive() //EV_RXCHAR
{
if (::IsWindow(_hNotifyWnd))
::PostMessage(_hNotifyWnd, ON_COM_RECEIVE, WPARAM(_dwPort), LPARAM (0));
}
virtual void OnDSR()
{
if (::IsWindow(_hNotifyWnd))
{
DWORD Status;
if (GetCommModemStatus(_hCommHandle, &Status))
::PostMessage(_hNotifyWnd, ON_COM_DSR, WPARAM(_dwPort),LPARAM((Status &MS_DSR_ON) ? 1 : 0));
}
}
virtual void OnCTS()
{
if (::IsWindow(_hNotifyWnd))
{
DWORD Status;
if (GetCommModemStatus(_hCommHandle, &Status))
::PostMessage(_hNotifyWnd, ON_COM_CTS, WPARAM(_dwPort), LPARAM( (Status &MS_CTS_ON) ? 1 : 0));
}
}
virtual void OnBreak()
{
if (::IsWindow(_hNotifyWnd))
{
::PostMessage(_hNotifyWnd, ON_COM_BREAK, WPARAM(_dwPort), LPARAM(0));
}
}
virtual void OnTXEmpty()
{
if (::IsWindow(_hNotifyWnd))
::PostMessage(_hNotifyWnd, ON_COM_TXEMPTY, WPARAM(_dwPort), LPARAM (0));
}
virtual void OnError()
{
DWORD dwError;
::ClearCommError(_hCommHandle, &dwError, NULL);
if (::IsWindow(_hNotifyWnd))
::PostMessage(_hNotifyWnd, ON_COM_ERROR, WPARAM(_dwPort), LPARAM (dwError));
}
virtual void OnRing()
{
if (::IsWindow(_hNotifyWnd))
::PostMessage(_hNotifyWnd, ON_COM_RING, WPARAM(_dwPort), LPARAM(0));
}
virtual void OnRLSD()
{
if (::IsWindow(_hNotifyWnd))
::PostMessage(_hNotifyWnd, ON_COM_RLSD, WPARAM(_dwPort), LPARAM(0));
}
virtual DWORD ThreadFunc()
{
if (!::SetCommMask(_hCommHandle, _dwMaskEvent))
{
char szBuffer[256];
_snprintf(szBuffer, 255,
"%s(%d) : COM%d Call WINAPI SetCommMask(%x, %x) Fail, thread work invalid! GetLastError() = %d;", __FILE__, __LINE__, _dwPort, _hCommHandle, _dwMaskEvent, GetLastError());
MessageBox(NULL, szBuffer, "Class cnComm", MB_OK);
return 1;
}
COMSTAT Stat;
DWORD dwError;
for (DWORD dwLength, dwMask = 0; _fRunFlag && IsOpen(); dwMask = 0)
{
if (!::WaitCommEvent(_hCommHandle, &dwMask, &_WaitOverlapped))
{
if (::GetLastError() == ERROR_IO_PENDING)
// asynchronous
::GetOverlappedResult(_hCommHandle, &_WaitOverlapped,&dwLength, TRUE);
else
continue;
}
if (dwMask == 0)
continue;
switch (dwMask)
{
case EV_RXCHAR:
::ClearCommError(_hCommHandle, &dwError, &Stat);
if (Stat.cbInQue >= _dwNotifyNum)
OnReceive();
break;
case EV_TXEMPTY:
OnTXEmpty();
break;
case EV_CTS:
OnCTS();
break;
case EV_DSR:
OnDSR();
break;
case EV_RING:
OnRing();
break;
case EV_RLSD:
OnRLSD();
break;
case EV_BREAK:
OnBreak();
break;
case EV_ERR:
OnError();
break;
} //case
} //for
return 0;
}
private:
//the function protected
cnComm(const cnComm &);
cnComm &operator = (const cnComm &);
//base function for thread
static DWORD WINAPI CommThreadProc(LPVOID lpPara)
{
return ((cnComm*)lpPara)->ThreadFunc();
}
};
#endif //_CN_COMM_H_
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