📄 serialport.cpp
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/*
Module : SERIALPORT.CPP
Purpose: Implementation for an MFC wrapper class for serial ports
Created: PJN / 31-05-1999
History: PJN / 03-06-1999 1. Fixed problem with code using CancelIo which does not exist on 95.
2. Fixed leaks which can occur in sample app when an exception is thrown
PJN / 16-06-1999 1. Fixed a bug whereby CString::ReleaseBuffer was not being called in
CSerialException::GetErrorMessage
PJN / 29-09-1999 1. Fixed a simple copy and paste bug in CSerialPort::SetDTR
PJN / 08-05-2000 1. Fixed an unreferrenced variable in CSerialPort::GetOverlappedResult in VC 6
PJN / 10-12-2000 1. Made class destructor virtual
PJN / 15-01-2001 1. Attach method now also allows you to specify whether the serial port
is being attached to in overlapped mode
2. Removed some ASSERTs which were unnecessary in some of the functions
3. Updated the Read method which uses OVERLAPPED IO to also return the bytes
read. This allows calls to WriteFile with a zeroed overlapped structure (This
is required when dealing with TAPI and serial communications)
4. Now includes copyright message in the source code and documentation.
PJN / 24-03-2001 1. Added a BytesWaiting method
PJN / 04-04-2001 1. Provided an overriden version of BytesWaiting which specifies a timeout
PJN / 23-04-2001 1. Fixed a memory leak in DataWaiting method
PJN / 01-05-2002 1. Fixed a problem in Open method which was failing to initialize the DCB
structure incorrectly, when calling GetState. Thanks to Ben Newson for this fix.
PJN / 29-05-2002 1. Fixed an problem where the GetProcAddress for CancelIO was using the
wrong calling convention
PJN / 07-08-2002 1. Changed the declaration of CSerialPort::WaitEvent to be consistent with the
rest of the methods in CSerialPort which can operate in "OVERLAPPED" mode. A note
about the usage of this: If the method succeeds then the overlapped operation
has completed synchronously and there is no need to do a WaitForSingle/MultipleObjects.
If any other unexpected error occurs then a CSerialException will be thrown. See
the implementation of the CSerialPort::DataWaiting which has been rewritten to use
this new design pattern. Thanks to Serhiy Pavlov for spotting this inconsistency.
PJN / 20-09-2002 1. Addition of an additional ASSERT in the internal _OnCompletion function.
2. Addition of an optional out parameter to the Write method which operates in
overlapped mode. Thanks to Kevin Pinkerton for this addition.
PJN / 10-04-2006 1. Updated copyright details.
2. Addition of a CSERIALPORT_EXT_CLASS and CSERIALPORT_EXT_API macros which makes
the class easier to use in an extension dll.
3. Removed derivation of CSerialPort from CObject as it was not really needed.
4. Fixed a number of level 4 warnings in the sample app.
5. Reworked the overlapped IO methods to expose the LPOVERLAPPED structure to client
code.
6. Updated the documentation to use the same style as the web site.
7. Did a spell check of the HTML documentation.
8. Updated the documentation on possible blocking in Read/Ex function. Thanks to
D Kerrison for reporting this issue.
9. Fixed a minor issue in the sample app when the code is compiled using /Wp64
PJN / 02-06-2006 1. Removed the bOverlapped as a member variable from the class. There was no
real need for this setting, since the SDK functions will perform their own
checking of how overlapped operations should
2. Fixed a bug in GetOverlappedResult where the code incorrectly checking against
the error ERROR_IO_PENDING instead of ERROR_IO_INCOMPLETE. Thanks to Sasho Darmonski
for reporting this bug.
3. Reviewed all TRACE statements for correctness.
PJN / 05-06-2006 1. Fixed an issue with the creation of the internal event object. It was incorrectly
being created as an auto-reset event object instead of a manual reset event object.
Thanks to Sasho Darmonski for reporting this issue.
PJN / 24-06-2006 1. Fixed some typos in the history list. Thanks to Simon Wong for reporting this.
2. Made the class which handles the construction of function pointers at runtime a
member variable of CSerialPort
3. Made AfxThrowSerialPortException part of the CSerialPort class. Thanks to Simon Wong
for reporting this.
4. Removed the unnecessary CSerialException destructor. Thanks to Simon Wong for
reporting this.
5. Fixed a minor error in the TRACE text in CSerialPort::SetDefaultConfig. Again thanks
to Simon Wong for reporting this.
6. Code now uses new C++ style casts rather than old style C casts where necessary.
Again thanks to Simon Wong for reporting this.
7. CSerialException::GetErrorMessage now uses the strsafe functions. This does mean
that the code now requires the Platform SDK if compiled using VC 6.
PJN / 25-06-2006 1. Combined the functionality of the CSerialPortData class into the main CSerialPort class.
2. Renamed AfxThrowSerialPortException to ThrowSerialPortException and made the method
public.
Copyright (c) 1996 - 2006 by PJ Naughter (Web: www.naughter.com, Email: pjna@naughter.com)
All rights reserved.
Copyright / Usage Details:
You are allowed to include the source code in any product (commercial, shareware, freeware or otherwise)
when your product is released in binary form. You are allowed to modify the source code in any way you want
except you cannot modify the copyright details at the top of each module. If you want to distribute source
code with your application, then you are only allowed to distribute versions released by the author. This is
to maintain a single distribution point for the source code.
*/
///////////////////////////////// Includes //////////////////////////////////
#include "stdafx.h"
#include "serialport.h"
#include "RuntimeException.h"
#ifndef _STRSAFE_H_INCLUDED_
#pragma message("To avoid this message, please put strsafe.h in your PCH (normally stdafx.h)")
#include <strsafe.h>
#endif
///////////////////////////////// Defines /////////////////////////////////////
#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif
//////////////////////////////// Implementation ///////////////////////////////
CSerialPort::CSerialPort() : m_hComm(INVALID_HANDLE_VALUE),
m_hEvent(NULL)
{
m_hKernel32 = GetModuleHandle(_T("KERNEL32.DLL"));
VERIFY(m_hKernel32 != NULL);
m_lpfnCancelIo = (LPCANCELIO) GetProcAddress(m_hKernel32, "CancelIo");
}
CSerialPort::~CSerialPort()
{
Close();
}
void CSerialPort::ThrowSerialException(DWORD dwError /*= 0*/)
{
if (dwError == 0)
dwError = ::GetLastError();
CRuntimeException* pException = new CRuntimeException (dwError);
TRACE(_T("Warning: throwing CRuntimeException for error %d\n"), dwError);
THROW(pException);
}
#ifdef _DEBUG
void CSerialPort::Dump(CDumpContext& dc) const
{
dc << _T("m_hComm = ") << m_hComm << _T("\n");
}
#endif
void CSerialPort::SetDataBytes(BYTE dataBits)
{
//Get the current state prior to changing it
DCB dcb;
dcb.DCBlength = sizeof(DCB);
GetState(dcb);
dcb.ByteSize = dataBits;
SetState(dcb);
}
void CSerialPort::SetBaud(DWORD dwBaud)
{
//Get the current state prior to changing it
DCB dcb;
dcb.DCBlength = sizeof(DCB);
GetState(dcb);
dcb.BaudRate = dwBaud;
SetState(dcb);
}
void CSerialPort::SetParity(Parity parity)
{
//Get the current state prior to changing it
DCB dcb;
dcb.DCBlength = sizeof(DCB);
GetState(dcb);
//Setup the Parity
switch (parity)
{
case EvenParity: dcb.Parity = EVENPARITY; break;
case MarkParity: dcb.Parity = MARKPARITY; break;
case NoParity: dcb.Parity = NOPARITY; break;
case OddParity: dcb.Parity = ODDPARITY; break;
case SpaceParity: dcb.Parity = SPACEPARITY; break;
default: ASSERT(FALSE); break;
}
SetState(dcb);
}
void CSerialPort::SetStopBits(StopBits stopbits)
{
//Get the current state prior to changing it
DCB dcb;
dcb.DCBlength = sizeof(DCB);
GetState(dcb);
//Setup the stop bits
switch (stopbits)
{
case OneStopBit: dcb.StopBits = ONESTOPBIT; break;
case OnePointFiveStopBits: dcb.StopBits = ONE5STOPBITS; break;
case TwoStopBits: dcb.StopBits = TWOSTOPBITS; break;
default: ASSERT(FALSE); break;
}
SetState(dcb);
}
void CSerialPort::SetFlowControl(FlowControl fc)
{
//Get the current state prior to changing it
DCB dcb;
dcb.DCBlength = sizeof(DCB);
GetState(dcb);
//Setup the flow control
dcb.fDsrSensitivity = FALSE;
switch (fc)
{
case NoFlowControl:
{
dcb.fOutxCtsFlow = FALSE;
dcb.fOutxDsrFlow = FALSE;
dcb.fOutX = FALSE;
dcb.fInX = FALSE;
break;
}
case CtsRtsFlowControl:
{
dcb.fOutxCtsFlow = TRUE;
dcb.fOutxDsrFlow = FALSE;
dcb.fRtsControl = RTS_CONTROL_HANDSHAKE;
dcb.fOutX = FALSE;
dcb.fInX = FALSE;
break;
}
case CtsDtrFlowControl:
{
dcb.fOutxCtsFlow = TRUE;
dcb.fOutxDsrFlow = FALSE;
dcb.fDtrControl = DTR_CONTROL_HANDSHAKE;
dcb.fOutX = FALSE;
dcb.fInX = FALSE;
break;
}
case DsrRtsFlowControl:
{
dcb.fOutxCtsFlow = FALSE;
dcb.fOutxDsrFlow = TRUE;
dcb.fRtsControl = RTS_CONTROL_HANDSHAKE;
dcb.fOutX = FALSE;
dcb.fInX = FALSE;
break;
}
case DsrDtrFlowControl:
{
dcb.fOutxCtsFlow = FALSE;
dcb.fOutxDsrFlow = TRUE;
dcb.fDtrControl = DTR_CONTROL_HANDSHAKE;
dcb.fOutX = FALSE;
dcb.fInX = FALSE;
break;
}
case XonXoffFlowControl:
{
dcb.fOutxCtsFlow = FALSE;
dcb.fOutxDsrFlow = FALSE;
dcb.fOutX = TRUE;
dcb.fInX = TRUE;
dcb.XonChar = 0x11;
dcb.XoffChar = 0x13;
dcb.XoffLim = 100;
dcb.XonLim = 100;
break;
}
default:
{
ASSERT(FALSE);
break;
}
}
SetState(dcb);
}
void CSerialPort::Open(int nPort, DWORD dwBaud, Parity parity, BYTE DataBits, StopBits stopbits, FlowControl fc, BOOL bOverlapped)
{
//Validate our parameters
ASSERT(nPort>0 && nPort<=255);
Close(); //In case we are already open
//Call CreateFile to open the comms port
CString sPort;
sPort.Format(_T("\\\\.\\COM%d"), nPort);
m_hComm = CreateFile(sPort, GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, bOverlapped ? FILE_FLAG_OVERLAPPED : 0, NULL);
if (m_hComm == INVALID_HANDLE_VALUE)
{
TRACE(_T("CSerialPort::Open, Failed to open the comms port\n"));
ThrowSerialException();
}
//Create the event we need for later synchronisation use
m_hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
if (m_hEvent == NULL)
{
Close();
TRACE(_T("CSerialPort::Open, Failed in call to CreateEvent in Open\n"));
ThrowSerialException();
}
//Get the current state prior to changing it
DCB dcb;
dcb.DCBlength = sizeof(DCB);
GetState(dcb);
//Setup the baud rate
dcb.BaudRate = dwBaud;
//Setup the Parity
switch (parity)
{
case EvenParity: dcb.Parity = EVENPARITY; break;
case MarkParity: dcb.Parity = MARKPARITY; break;
case NoParity: dcb.Parity = NOPARITY; break;
case OddParity: dcb.Parity = ODDPARITY; break;
case SpaceParity: dcb.Parity = SPACEPARITY; break;
default: ASSERT(FALSE); break;
}
//Setup the data bits
dcb.ByteSize = DataBits;
//Setup the stop bits
switch (stopbits)
{
case OneStopBit: dcb.StopBits = ONESTOPBIT; break;
case OnePointFiveStopBits: dcb.StopBits = ONE5STOPBITS; break;
case TwoStopBits: dcb.StopBits = TWOSTOPBITS; break;
default: ASSERT(FALSE); break;
}
//Setup the flow control
dcb.fDsrSensitivity = FALSE;
switch (fc)
{
case NoFlowControl:
{
dcb.fOutxCtsFlow = FALSE;
dcb.fOutxDsrFlow = FALSE;
dcb.fOutX = FALSE;
dcb.fInX = FALSE;
break;
}
case CtsRtsFlowControl:
{
dcb.fOutxCtsFlow = TRUE;
dcb.fOutxDsrFlow = FALSE;
dcb.fRtsControl = RTS_CONTROL_HANDSHAKE;
dcb.fOutX = FALSE;
dcb.fInX = FALSE;
break;
}
case CtsDtrFlowControl:
{
dcb.fOutxCtsFlow = TRUE;
dcb.fOutxDsrFlow = FALSE;
dcb.fDtrControl = DTR_CONTROL_HANDSHAKE;
dcb.fOutX = FALSE;
dcb.fInX = FALSE;
break;
}
case DsrRtsFlowControl:
{
dcb.fOutxCtsFlow = FALSE;
dcb.fOutxDsrFlow = TRUE;
dcb.fRtsControl = RTS_CONTROL_HANDSHAKE;
dcb.fOutX = FALSE;
dcb.fInX = FALSE;
break;
}
case DsrDtrFlowControl:
{
dcb.fOutxCtsFlow = FALSE;
dcb.fOutxDsrFlow = TRUE;
dcb.fDtrControl = DTR_CONTROL_HANDSHAKE;
dcb.fOutX = FALSE;
dcb.fInX = FALSE;
break;
}
case XonXoffFlowControl:
{
dcb.fOutxCtsFlow = FALSE;
dcb.fOutxDsrFlow = FALSE;
dcb.fOutX = TRUE;
dcb.fInX = TRUE;
dcb.XonChar = 0x11;
dcb.XoffChar = 0x13;
dcb.XoffLim = 100;
dcb.XonLim = 100;
break;
}
default:
{
ASSERT(FALSE);
break;
}
}
//Now that we have all the settings in place, make the changes
SetState(dcb);
}
void CSerialPort::Close()
{
if (IsOpen())
{
//Close down the comms port
BOOL bSuccess = CloseHandle(m_hComm);
m_hComm = INVALID_HANDLE_VALUE;
if (!bSuccess)
TRACE(_T("CSerialPort::Close, Failed to close up the comms port, GetLastError:%d\n"), GetLastError());
//Free the event object we are using
if (m_hEvent)
{
CloseHandle(m_hEvent);
m_hEvent = NULL;
}
}
}
void CSerialPort::Attach(HANDLE hComm)
{
Close();
//Validate our parameters, now that the port has been closed
ASSERT(m_hComm == INVALID_HANDLE_VALUE);
ASSERT(m_hEvent == NULL);
m_hComm = hComm;
//Create the event we need for later synchronisation use
m_hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
if (m_hEvent == NULL)
{
DWORD dwError = GetLastError();
Close();
TRACE(_T("CSerialPort::Attach, Failed in call to CreateEvent in Attach\n"));
ThrowSerialException(dwError);
}
}
HANDLE CSerialPort::Detach()
{
//What will be the return value from this function
HANDLE hrVal = m_hComm;
m_hComm = INVALID_HANDLE_VALUE;
if (m_hEvent)
{
CloseHandle(m_hEvent);
m_hEvent = NULL;
}
return hrVal;
}
DWORD CSerialPort::Read(void* lpBuf, DWORD dwCount)
{
ASSERT(IsOpen());
DWORD dwBytesRead = 0;
if (!ReadFile(m_hComm, lpBuf, dwCount, &dwBytesRead, NULL))
{
TRACE(_T("CSerialPort::Read, Failed in call to ReadFile\n"));
ThrowSerialException();
}
return dwBytesRead;
}
BOOL CSerialPort::Read(void* lpBuf, DWORD dwCount, OVERLAPPED& overlapped, DWORD* pBytesRead)
{
ASSERT(IsOpen());
DWORD dwBytesRead = 0;
BOOL bSuccess = ReadFile(m_hComm, lpBuf, dwCount, &dwBytesRead, &overlapped);
if (!bSuccess)
{
if (GetLastError() != ERROR_IO_PENDING)
{
TRACE(_T("CSerialPort::Read, Failed in call to ReadFile\n"));
ThrowSerialException();
}
}
else
{
if (pBytesRead)
*pBytesRead = dwBytesRead;
}
return bSuccess;
}
DWORD CSerialPort::Write(const void* lpBuf, DWORD dwCount)
{
ASSERT(IsOpen());
DWORD dwBytesWritten = 0;
if (!WriteFile(m_hComm, lpBuf, dwCount, &dwBytesWritten, NULL))
{
TRACE(_T("CSerialPort::Write, Failed in call to WriteFile\n"));
ThrowSerialException();
}
return dwBytesWritten;
}
BOOL CSerialPort::Write(const void* lpBuf, DWORD dwCount, OVERLAPPED& overlapped, DWORD* pBytesWritten)
{
ASSERT(IsOpen());
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