flightgear/Lib/Serial/serial.cxx

// serial.cxx -- Unix serial I/O support
//
// Written by Curtis Olson, started November 1998.
//
// Copyright (C) 1998  Curtis L. Olson - curt@flightgear.org
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of the
// License, or (at your option) any later version.
//
// 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., 675 Mass Ave, Cambridge, MA 02139, USA.
//
// $Id$


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

#include "Include/compiler.h"
#ifdef FG_HAVE_STD_INCLUDE
#  include <cerrno>
#else
#  include <errno.h>
#endif

#if defined( WIN32 ) && !defined( __CYGWIN__) && !defined( __CYGWIN32__ )
  // maybe include something???
#else
#  include <termios.h>
#  include <sys/types.h>
#  include <sys/stat.h>
#  include <fcntl.h>
#  include <unistd.h>
#endif

#include <Debug/logstream.hxx>

#include "serial.hxx"


fgSERIAL::fgSERIAL()
    : dev_open(false)
{
    // empty
}

fgSERIAL::fgSERIAL(const string& device, int baud) {
    open_port(device);
    
    if ( dev_open ) {
	set_baud(baud);
    }
}

fgSERIAL::~fgSERIAL() {
    // closing the port here screws us up because if we would even so
    // much as make a copy of an fgSERIAL object and then delete it,
    // the file descriptor gets closed.  Doh!!!
}

bool fgSERIAL::open_port(const string& device) {

#if defined( WIN32 ) && !defined( __CYGWIN__) && !defined( __CYGWIN32__ )

    fd = CreateFile( device.c_str(),
        GENERIC_READ | GENERIC_WRITE,
        0, // dwShareMode
        NULL, // lpSecurityAttributes
        OPEN_EXISTING,
        FILE_FLAG_OVERLAPPED,
        NULL );
    if ( fd == 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 );

        FG_LOG( FG_SERIAL, FG_ALERT, "Error opening serial device \"" 
            << device << "\" " << (const char*) lpMsgBuf );
        LocalFree( lpMsgBuf );
        return false;
    }

    dev_open = true;
    return true;

#else

    struct termios config;

    fd = open(device.c_str(), O_RDWR | O_NONBLOCK);
    cout << "Serial fd created = " << fd << endl;

    if ( fd  == -1 ) {
	FG_LOG( FG_SERIAL, FG_ALERT, "Cannot open " << device
		<< " for serial I/O" );
	return false;
    } else {
	dev_open = true;
    }

    // set required port parameters 
    if ( tcgetattr( fd, &config ) != 0 ) {
	FG_LOG( FG_SERIAL, FG_ALERT, "Unable to poll port settings" );
	return false;
    }

    // cfmakeraw( &config );

    // cout << "config.c_iflag = " << config.c_iflag << endl;

    // software flow control on
    config.c_iflag |= IXON;
    // config.c_iflag |= IXOFF;

    // config.c_cflag |= CLOCAL;

#if ! defined( sgi )    
    // disable hardware flow control
    config.c_cflag &= ~(CRTSCTS);
#endif

    // cout << "config.c_iflag = " << config.c_iflag << endl;

    if ( tcsetattr( fd, TCSANOW, &config ) != 0 ) {
	FG_LOG( FG_SERIAL, FG_ALERT, "Unable to update port settings" );
	return false;
    }

    return true;
#endif
}


bool fgSERIAL::close_port() {
#if defined( WIN32 ) && !defined( __CYGWIN__) && !defined( __CYGWIN32__ )
    CloseHandle( fd );
#else
    close(fd);
#endif

    return true;
}


bool fgSERIAL::set_baud(int baud) {

#if defined( WIN32 ) && !defined( __CYGWIN__) && !defined( __CYGWIN32__ )

    return true;

#else

    struct termios config;
    speed_t speed = B9600;

    if ( tcgetattr( fd, &config ) != 0 ) {
	FG_LOG( FG_SERIAL, FG_ALERT, "Unable to poll port settings" );
	return false;
    }

    if ( baud == 300 ) {
	speed = B300;
    } else if ( baud == 1200 ) {
	speed = B1200;
    } else if ( baud == 2400 ) {
	speed = B2400;
    } else if ( baud == 4800 ) {
	speed = B4800;
    } else if ( baud == 9600 ) {
	speed = B9600;
    } else if ( baud == 19200 ) {
	speed = B19200;
    } else if ( baud == 38400 ) {
	speed = B38400;
    } else if ( baud == 57600 ) {
	speed = B57600;
    } else if ( baud == 115200 ) {
	speed = B115200;
#if defined( linux ) || defined( __FreeBSD__ )
    } else if ( baud == 230400 ) {
	speed = B230400;
#endif
    } else {
	FG_LOG( FG_SERIAL, FG_ALERT, "Unsupported baud rate " << baud );
	return false;
    }

    if ( cfsetispeed( &config, speed ) != 0 ) {
	FG_LOG( FG_SERIAL, FG_ALERT, "Problem setting input baud rate" );
	return false;
    }

    if ( cfsetospeed( &config, speed ) != 0 ) {
	FG_LOG( FG_SERIAL, FG_ALERT, "Problem setting output baud rate" );
	return false;
    }

    if ( tcsetattr( fd, TCSANOW, &config ) != 0 ) {
	FG_LOG( FG_SERIAL, FG_ALERT, "Unable to update port settings" );
	return false;
    }

    return true;

#endif

}

string fgSERIAL::read_port() {

#if defined( WIN32 ) && !defined( __CYGWIN__) && !defined( __CYGWIN32__ )

    string result = "";
    return result;

#else

    const int max_count = 1024;
    char buffer[max_count+1];
    int count;
    string result;

    count = read(fd, buffer, max_count);
    // cout << "read " << count << " bytes" << endl;

    if ( count < 0 ) {
	// error condition
	if ( errno != EAGAIN ) {
	    FG_LOG( FG_SERIAL, FG_ALERT, 
		    "Serial I/O on read, error number = " << errno );
	}

	return "";
    } else {
	buffer[count] = '\0';
	result = buffer;

	return result;
    }

#endif

}

int fgSERIAL::write_port(const string& value) {

#if defined( WIN32 ) && !defined( __CYGWIN__) && !defined( __CYGWIN32__ )

    LPCVOID lpBuffer = value.c_str();
    DWORD nNumberOfBytesToWrite = value.length();
    DWORD lpNumberOfBytesWritten;
    OVERLAPPED lpOverlapped;

    if ( WriteFile( fd,
        lpBuffer,
        nNumberOfBytesToWrite,
        &lpNumberOfBytesWritten,
        &lpOverlapped ) == 0 )
    {
        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 );

        FG_LOG( FG_SERIAL, FG_ALERT, "Serial I/O write error: " 
             << (const char*) lpMsgBuf );
        LocalFree( lpMsgBuf );
        return int(lpNumberOfBytesWritten);
    }

    return int(lpNumberOfBytesWritten);

#else

    static bool error = false;
    int count;

    if ( error ) {
	// attempt some sort of error recovery
	count = write(fd, "\n", 1);
	if ( count == 1 ) {
	    // cout << "Serial error recover successful!\n";
	    error = false;
	} else {
	    return 0;
	}
    }

    count = write(fd, value.c_str(), value.length());
    // cout << "write '" << value << "'  " << count << " bytes" << endl;

    if ( (int)count == (int)value.length() ) {
	error = false;
    } else {
	error = true;
	if ( errno == EAGAIN ) {
	    // ok ... in our context we don't really care if we can't
	    // write a string, we'll just get it the next time around
	} else {
	    FG_LOG( FG_SERIAL, FG_ALERT,
		    "Serial I/O on write, error number = " << errno );
	}
    }

    return count;

#endif

}