serialio-win32.cpp

Powerful and Portable GPS application -- support Linux, Windows, Windows CE GPS navigation and Map m

/*
 *  Roadnav
 *  SerialIO-Win32.cpp
 *
 *  Copyright (c) 2004 - 2007 Richard L. Lynch <[e-mail]>
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of version 2 of the GNU General Public License
 *  as published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */ 
 
//////////////////////////////////////////////////////////////////////////////
/// \file
///
/// Windows serial support functions
///
//////////////////////////////////////////////////////////////////////////////

#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif

#include <wx/wx.h>

#include "SerialIO.h"
#include "App.h"

#if defined(__WINDOWS__)

#include <stdio.h>
#include <windows.h>

HANDLE hCom = NULL;
static wxString g_strSerialError;

wxString GetLastSerialIOError()
{
	return g_strSerialError;
}

//////////////////////////////////////////////////////////////////////////////
///
/// \brief Get the name of the nth serial port in the computer
///
//////////////////////////////////////////////////////////////////////////////
wxString EnumSerialPort(int n)
{
	int iPort;
	int iCount;
	
	iCount = 0;
	for (iPort = 1; iPort <= 256; iPort++)
	{
		wxString strName;
		COMMCONFIG cc;
		DWORD dwCCSize;
		
		strName = wxString::Format(wxT("COM%d"), iPort);
		
		dwCCSize = sizeof(cc);
		
		if (GetDefaultCommConfig(strName, &cc, &dwCCSize))
		{
			HANDLE hCom;
			
			hCom = CreateFile(
					strName,
					GENERIC_WRITE | GENERIC_READ,
					0,
					0,
					OPEN_EXISTING,
					0, 
					NULL);
			
			if (hCom)
			{
				iCount++;
				
				CloseHandle(hCom);

				if (iCount > n)
					return strName;
			}
		}
	}
	return wxT("");
}

//////////////////////////////////////////////////////////////////////////////
///
/// \brief Initialize serial port
///
//////////////////////////////////////////////////////////////////////////////
bool InitSerialIO()
{
	wxString strPort;
	int iBaudRate;

	g_pConfig->Read(wxT("GPSSerialPort"), &strPort, wxT(""));
	g_pConfig->Read(wxT("GPSBaudRate"), &iBaudRate, 4800);

	if (strPort == wxT("") || iBaudRate <= 0)
	{
		hCom = NULL;
		g_strSerialError = wxT("Invalid COM port or baud rate");
		return true;
	}

	hCom = CreateFile(
			wxT("\\\\.\\") + strPort,
			GENERIC_WRITE | GENERIC_READ,
			0,
			0,
			OPEN_EXISTING,
			0, 
			NULL);
			
	if (hCom == INVALID_HANDLE_VALUE)
	{
		LPVOID lpMsgBuf;

		FormatMessage( 
			FORMAT_MESSAGE_ALLOCATE_BUFFER | 
			FORMAT_MESSAGE_FROM_SYSTEM | 
			FORMAT_MESSAGE_IGNORE_INSERTS,
			NULL,
			GetLastError(),
			MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
			(LPTSTR) &lpMsgBuf,
			0,
			NULL 
		);
		
		g_strSerialError = strPort + wxT(": ") + (LPTSTR) lpMsgBuf;

		// Free the buffer.
		LocalFree( lpMsgBuf );
		return true;
	}

	DCB dcb;

	ZeroMemory(&dcb, sizeof(DCB));

	GetCommState(hCom, &dcb);

	BuildCommDCB(wxString::Format(wxT("baud=%d parity=N data=8 stop=1"), iBaudRate), &dcb);

	SetupComm(hCom, 4096, 4096);
	
	SetCommState(hCom, &dcb);

	COMMTIMEOUTS sCT;

	memset(&sCT, 0, sizeof(sCT));
	sCT.ReadTotalTimeoutConstant = 1000;

	SetCommTimeouts(hCom, &sCT);

	return false;
}

//////////////////////////////////////////////////////////////////////////////
///
/// \brief Read up to nBuffer bytes into szBuffer.
///
/// Should block if nothing is available, and return as soon as anything is
/// available.
///
////////////////////////////////////////////////////////////////////////////
int ReadSerial(char * szBuffer, int nBuffer)
{
	DWORD dwBytesIn = 0;
	
	if (!hCom)
	{
		wxThread::Sleep(1000);
		*szBuffer = 0;
		return 0;
	}

	ReadFile(hCom, szBuffer, nBuffer - 1, &dwBytesIn, NULL);

	if (dwBytesIn >= 0)
		szBuffer[dwBytesIn] = 0;

	szBuffer[nBuffer - 1] = 0;

	if (dwBytesIn <= 0)
	{
		wxThread::Sleep(1000);

		dwBytesIn = 0;
	}

	return dwBytesIn;
}

//////////////////////////////////////////////////////////////////////////////
///
/// \brief Clean up serial stuff.
///
//////////////////////////////////////////////////////////////////////////////
bool ShutdownSerialIO()
{
	if (hCom)
	{
		CloseHandle(hCom); //close the handle
		hCom = NULL;
	}

	return false;
}

#endif