serialport.cpp

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//======================================================================
// File:        serialport.cpp
// Author:      Matthias Toussaint
// Created:     Sat Nov 25 13:49:23 CET 2006
// Project:     QtDMM
// Description: Encapsulation of serial port
//----------------------------------------------------------------------
// This file  may  be used under  the terms of  the GNU  General Public
// License  version 2.0 as published   by the Free Software  Foundation
// and appearing  in the file LICENSE.GPL included  in the packaging of
// this file.
// 
// This file is provided AS IS with  NO WARRANTY OF ANY KIND, INCLUDING 
// THE WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR 
// PURPOSE.
//----------------------------------------------------------------------
// Copyright 2006 Matthias Toussaint
//======================================================================

#include <serialport.h>
#include <errno.h>
#include <ctype.h>
#include <iostream>
#include <util.h>

SerialPort::SerialPort() : 
  Port()
{
}

SerialPort::~SerialPort()
{
  close();
}

Port::Error SerialPort::open( const std::string & config )
{
  bool rts=false, dtr=false, dsr=false, cts=false;
  
  TokenList token = Util::tokenize( config, ":" );
  int tokenCnt = token.size();
  
  for (int i=5; i<tokenCnt; ++i)
  {
    for (unsigned j=0; j<token[i].size(); ++j) 
    {
      token[i][j] = toupper( token[i][j] );
    }
    if (token[i] == "RTS")      rts=true;
    else if (token[i] == "DTR") dtr=true;
    else if (token[i] == "DSR") dsr=true;
    else if (token[i] == "CTS") cts=true;
  }
  
  int baud; 
  if (!Util::fromString( &baud, token[1] )) return Port::SyntaxError;
  int bits; 
  if (!Util::fromString( &bits, token[2] )) return Port::SyntaxError;
  int stopBits; 
  if (!Util::fromString( &stopBits, token[4] )) return Port::SyntaxError;
  
  int parity = -1;
  
  if (token[3] == "N" || token[3] == "n") parity = 0;
  if (token[3] == "E" || token[3] == "e") parity = 1;
  if (token[3] == "O" || token[3] == "o") parity = 2;
  
  if (parity == -1) return Port::UnknownParity;
  if (stopBits != 1 && stopBits != 2) return Port::UnknownStopBits;
  
  tcflag_t cflag = CREAD | CLOCAL;
  
  if (stopBits == 2)
  {
    cflag |= CSTOPB;
  }
  
  switch (bits)
  {
    case 5:
      cflag |= CS5;
      break;
    case 6:
      cflag |= CS6;
      break;
    case 7:
      cflag |= CS7;
      break;
    case 8:
      cflag |= CS8;
      break;
    default:
      return Port::UnknownNumberOfBits;
  }
  
  switch (parity)
  {
    case 0: // None
      break;
    case 1: // Even
      cflag |= PARENB;
      break;
    case 2: // Odd
      cflag |= PARENB;
      cflag |= PARODD;
  }    
  
  struct termios attr;
  int            mdlns;
  
  memset( &attr, 0, sizeof( struct termios ) );
  
  m_handle = ::open( token[0].c_str(), O_RDWR | O_NOCTTY | O_NDELAY);
  
  if (-1 == m_handle)
  {
    switch (errno) 
    {
      case EACCES:
        return Port::PermissionDenied;
      case ENXIO: 
      case ENODEV: 
      case ENOENT:
        return Port::NoSuchPort;
      default:  
        return Port::OpenError;
    }
  }
  
  fcntl( m_handle, F_SETFL, 0 );
  tcgetattr( m_handle, &m_oldSettings );
  
  attr.c_oflag = 0;
  attr.c_lflag = 0;
  attr.c_cflag = cflag;
  
  // According to Thomas Hoffman flags should be like this
  //
  if (0 == parity)          // Ignore parity errors
  {
    attr.c_iflag = IGNBRK | IGNPAR ;
  }
  else
  {
    attr.c_iflag = IGNBRK | INPCK | ISTRIP;
  }
  
  attr.c_cc[VTIME]= 0;
  attr.c_cc[VMIN]= 1;
  
  if (300 == baud)
  {
    cfsetospeed( &attr, B300 ); 
    cfsetispeed( &attr, B300 );
  }
  else if (600 == baud)
  {
    cfsetospeed( &attr, B600 ); 
    cfsetispeed( &attr, B600 );
  }
  else if (1200 == baud)
  {
    cfsetospeed( &attr, B1200 ); 
    cfsetispeed( &attr, B1200 );
  }
  else if (1800 == baud)
  {
    cfsetospeed( &attr, B1800 ); 
    cfsetispeed( &attr, B1800 );
  }
  else if (2400 == baud)
  {
    cfsetospeed( &attr, B2400 ); 
    cfsetispeed( &attr, B2400 );
  }
  else if (4800 == baud)
  {
    cfsetospeed( &attr, B4800 ); 
    cfsetispeed( &attr, B4800 );
  }
  else if (9600 == baud)
  {
    cfsetospeed( &attr, B9600 ); 
    cfsetispeed( &attr, B9600 );
  }
  else if (19200 == baud)
  {
    cfsetospeed( &attr, B19200 ); 
    cfsetispeed( &attr, B19200 );
  }
  else
  {
    cfsetospeed( &attr, B38400 ); 
    cfsetispeed( &attr, B38400 );
  }
  
  if (-1 == tcsetattr( m_handle, TCSANOW, &attr )) 
  {  
    goto config_error;
  }
  
  mdlns = 0;
  if (-1 == ioctl( m_handle, TIOCMGET, &mdlns )) 
  {
    goto config_error;
  }

  if (rts) mdlns |= TIOCM_RTS;
  else     mdlns &= ~TIOCM_RTS;

  if (dtr) mdlns |= TIOCM_DTR;
  else     mdlns &= ~TIOCM_DTR;

  if (dsr) mdlns |= TIOCM_DSR;
  else     mdlns &= ~TIOCM_DSR;

  if (cts) mdlns |= TIOCM_CTS;
  else     mdlns &= ~TIOCM_CTS;
  
  if (-1 == ioctl( m_handle, TIOCMSET, &mdlns )) 
  {
    goto config_error;
  }
  
  tcsetattr( m_handle, TCSAFLUSH, &attr );

  return Port::Ok;
  
config_error:
  ::close(m_handle);
  m_handle = -1;
    
  return Port::ConfigError;
}

Port::Error SerialPort::close()
{
  if (-1 != m_handle)
  {
    // restore
    ::tcsetattr( m_handle, TCSANOW, &m_oldSettings );
    ::close( m_handle );
    m_handle = -1;
  }
  
  return Port::Ok;
}

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