📄 serialport.cpp
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/*
** FILENAME CSerialPort.cpp
**
** PURPOSE This class can read, write and watch one serial port.
** It sends messages to its owner when something happends on the port
** The class creates a thread for reading and writing so the main
** program is not blocked.
**
** CREATION DATE 15-09-1997
** LAST MODIFICATION 12-11-1997
**
** AUTHOR Remon Spekreijse
**
**
*/
#include "stdafx.h"
#include "SerialPort.h"
#include <assert.h>
BEGIN_MESSAGE_MAP(CSerialPort::CSerialWnd, CWnd)
//{{AFX_MSG_MAP(CWnd)
ON_MESSAGE(WM_COMM_RXCHAR, CSerialPort::CSerialWnd::OnCommRxchar)
//}}AFX_MSG_MAP
END_MESSAGE_MAP()
CSerialPort::CSerialWnd::CSerialWnd() : m_pNotifyWnd(NULL), m_callbackProc(0)
{
}
BOOL CSerialPort::CSerialWnd::Create(CWnd * pNotifyWnd)
{
m_pNotifyWnd = pNotifyWnd;
return Create();
}
BOOL CSerialPort::CSerialWnd::Create(SMSCALLBACKPROC proc)
{
m_callbackProc = proc;
return Create();
}
BOOL CSerialPort::CSerialWnd::Create()
{
m_hWnd = NULL;
BOOL bRet = CreateEx(0, AfxRegisterWndClass(0), _T("串口消息窗口"), WS_OVERLAPPED, 0, 0, 0, 0, NULL, NULL);
if(bRet)
ShowWindow(SW_HIDE);
return bRet;
}
void CSerialPort::CSerialWnd::OnCommRxchar(WPARAM ch, LPARAM port)
{
//转发消息
if(m_pNotifyWnd != NULL && IsWindow(m_pNotifyWnd->m_hWnd))
m_pNotifyWnd->PostMessage(WM_COMM_RXCHAR, ch, port);
//回调
if(m_callbackProc != 0)
m_callbackProc(ch, port);
}
//
// 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_Thread = NULL;
}
//
// 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::Open(SMSCALLBACKPROC proc, // the owner (CWnd) of the port (receives message)
BOOL CSerialPort::Open(CWnd * pOwner, // 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;
}
//if(!m_serialWnd.Create(pPortOwner))
if(!m_serialWnd.Create(pOwner))
{
CloseHandle(m_hComm);
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.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()");
*/
SetCommTimeouts(m_hComm, &m_CommTimeouts);
SetCommMask(m_hComm, dwCommEvents);
GetCommState(m_hComm, &m_dcb);
m_dcb.fRtsControl = RTS_CONTROL_ENABLE; // set RTS bit high!
m_dcb.BaudRate = DWORD(baud);
m_dcb.ByteSize = BYTE(databits);
m_dcb.Parity = BYTE(parity);
m_dcb.StopBits = BYTE(stopbits);
m_dcb.fParity = (parity != NOPARITY);
// Set the new DCB structure
SetCommState(m_hComm, &m_dcb);
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);
StartMonitoring();
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.
//
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