/*
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 ASSERT's 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 0'ized 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/Multiple]Object.
                          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.



Copyright (c) 1996 - 2002 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"
#ifndef _WINERROR_
#include "winerror.h"
#endif



///////////////////////////////// defines /////////////////////////////////////

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif




//////////////////////////////// Implementation ///////////////////////////////

//Class which handles CancelIo function which must be constructed at run time
//since it is not imeplemented on NT 3.51 or Windows 95. To avoid the loader
//bringing up a message such as "Failed to load due to missing export...", the
//function is constructed using GetProcAddress. The CSerialPort::CancelIo 
//function then checks to see if the function pointer is NULL and if it is it 
//throws an exception using the error code ERROR_CALL_NOT_IMPLEMENTED which
//is what 95 would have done if it had implemented a stub for it in the first
//place !!

class _SERIAL_PORT_DATA
{
public:
//Constructors /Destructors
  _SERIAL_PORT_DATA();
  ~_SERIAL_PORT_DATA();

  HINSTANCE m_hKernel32;
  typedef BOOL (WINAPI CANCELIO)(HANDLE);
  typedef CANCELIO* LPCANCELIO;
  LPCANCELIO m_lpfnCancelIo;
};

_SERIAL_PORT_DATA::_SERIAL_PORT_DATA()
{
  m_hKernel32 = LoadLibrary(_T("KERNEL32.DLL"));
  VERIFY(m_hKernel32 != NULL);
  m_lpfnCancelIo = (LPCANCELIO) GetProcAddress(m_hKernel32, "CancelIo");
}

_SERIAL_PORT_DATA::~_SERIAL_PORT_DATA()
{
  FreeLibrary(m_hKernel32);
  m_hKernel32 = NULL;
}


//The local variable which handle the function pointers

_SERIAL_PORT_DATA _SerialPortData;




////////// Exception handling code

void AfxThrowSerialException(DWORD dwError /* = 0 */)
{
	if (dwError == 0)
		dwError = ::GetLastError();

	CSerialException* pException = new CSerialException(dwError);

	TRACE(_T("Warning: throwing CSerialException for error %d\n"), dwError);
	THROW(pException);
}

BOOL CSerialException::GetErrorMessage(LPTSTR pstrError, UINT nMaxError, PUINT pnHelpContext)
{
	ASSERT(pstrError != NULL && AfxIsValidString(pstrError, nMaxError));

	if (pnHelpContext != NULL)
		*pnHelpContext = 0;

	LPTSTR lpBuffer;
	BOOL bRet = FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
			                      NULL,  m_dwError, MAKELANGID(LANG_NEUTRAL, SUBLANG_SYS_DEFAULT),
			                      (LPTSTR) &lpBuffer, 0, NULL);

	if (bRet == FALSE)
		*pstrError = '\0';
	else
	{
		lstrcpyn(pstrError, lpBuffer, nMaxError);
		bRet = TRUE;

		LocalFree(lpBuffer);
	}

	return bRet;
}

CString CSerialException::GetErrorMessage()
{
  CString rVal;
  LPTSTR pstrError = rVal.GetBuffer(4096);
  GetErrorMessage(pstrError, 4096, NULL);
  rVal.ReleaseBuffer();
  return rVal;
}

CSerialException::CSerialException(DWORD dwError)
{
	m_dwError = dwError;
}

CSerialException::~CSerialException()
{
}

IMPLEMENT_DYNAMIC(CSerialException, CException)

#ifdef _DEBUG
void CSerialException::Dump(CDumpContext& dc) const
{
	CObject::Dump(dc);

	dc << "m_dwError = " << m_dwError;
}
#endif





////////// The actual serial port code

CSerialPort::CSerialPort()
{
  m_hComm = INVALID_HANDLE_VALUE;
  m_bOverlapped = FALSE;
  m_hEvent = NULL;
}

CSerialPort::~CSerialPort()
{
  Close();
}

IMPLEMENT_DYNAMIC(CSerialPort, CObject)

#ifdef _DEBUG
void CSerialPort::Dump(CDumpContext& dc) const
{
	CObject::Dump(dc);

	dc << _T("m_hComm = ") << m_hComm << _T("\n");
  dc << _T("m_bOverlapped = ") << m_bOverlapped;
}
#endif

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 up 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("Failed to open up the comms port\n"));
    AfxThrowSerialException();
  }

  //Create the event we need for later synchronisation use
  m_hEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
  if (m_hEvent == NULL)
  {
    Close();
    TRACE(_T("Failed in call to CreateEvent in Open\n"));
    AfxThrowSerialException();
  }
  
  m_bOverlapped = bOverlapped;

  //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("Failed to close up the comms port, GetLastError:%d\n"), GetLastError());
    m_bOverlapped = FALSE;

    //Free up the event object we are using
    CloseHandle(m_hEvent);
    m_hEvent = NULL;
  }
}

void CSerialPort::Attach(HANDLE hComm, BOOL bOverlapped)
{
  Close();
  m_hComm = hComm;  
  m_bOverlapped = bOverlapped;

  //Create the event we need for later synchronisation use
  m_hEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
  if (m_hEvent == NULL)
  {
    Close();
    TRACE(_T("Failed in call to CreateEvent in Attach\n"));
    AfxThrowSerialException();
  }
}

HANDLE CSerialPort::Detach()
{
  HANDLE hrVal = m_hComm;
  m_hComm = INVALID_HANDLE_VALUE;
  CloseHandle(m_hEvent);
  m_hEvent = NULL;
  return hrVal;
}

DWORD CSerialPort::Read(void* lpBuf, DWORD dwCount)
{
  ASSERT(IsOpen());
  ASSERT(!m_bOverlapped);

  DWORD dwBytesRead = 0;
  if (!ReadFile(m_hComm, lpBuf, dwCount, &dwBytesRead, NULL))
  {
    TRACE(_T("Failed in call to ReadFile\n"));
    AfxThrowSerialException();
  }

  return dwBytesRead;
}

BOOL CSerialPort::Read(void* lpBuf, DWORD dwCount, OVERLAPPED& overlapped, DWORD* pBytesRead)
{
  ASSERT(IsOpen());
  ASSERT(m_bOverlapped);

  DWORD dwBytesRead = 0;
  BOOL bSuccess = ReadFile(m_hComm, lpBuf, dwCount, &dwBytesRead, &overlapped);
  if (!bSuccess)
  {
    if (GetLastError() != ERROR_IO_PENDING)
    {
      TRACE(_T("Failed in call to ReadFile\n"));
      AfxThrowSerialException();
    }
  }
  else
  {
    if (pBytesRead)
      *pBytesRead = dwBytesRead;
  }
  return bSuccess;
}

DWORD CSerialPort::Write(const void* lpBuf, DWORD dwCount)
{
  ASSERT(IsOpen());
  ASSERT(!m_bOverlapped);

  DWORD dwBytesWritten = 0;
  if (!WriteFile(m_hComm, lpBuf, dwCount, &dwBytesWritten, NULL))
  {
    TRACE(_T("Failed in call to WriteFile\n"));
    AfxThrowSerialException();
  }

  return dwBytesWritten;
}

BOOL CSerialPort::Write(const void* lpBuf, DWORD dwCount, OVERLAPPED& overlapped, DWORD* pBytesWritten)
{
  ASSERT(IsOpen());
  ASSERT(m_bOverlapped);

  DWORD dwBytesWritten = 0;
  BOOL bSuccess = WriteFile(m_hComm, lpBuf, dwCount, &dwBytesWritten, &overlapped);
  if (!bSuccess)
  {
    if (GetLastError() != ERROR_IO_PENDING)
    {
      TRACE(_T("Failed in call to WriteFile\n"));
      AfxThrowSerialException();
    }
  }
  else
  {
    if (pBytesWritten)
      *pBytesWritten = dwBytesWritten;
  }

  return bSuccess;
}

void CSerialPort::GetOverlappedResult(OVERLAPPED& overlapped, DWORD& dwBytesTransferred, BOOL bWait)
{
  ASSERT(IsOpen());
  ASSERT(m_bOverlapped);

  if (!::GetOverlappedResult(m_hComm, &overlapped, &dwBytesTransferred, bWait))
  {
    if (GetLastError() != ERROR_IO_PENDING)
    {
      TRACE(_T("Failed in call to GetOverlappedResult\n"));