port.cpp

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//======================================================================
// File:        port.cpp
// Author:      Matthias Toussaint
// Created:     Sat Nov 25 13:49:23 CET 2006
// Project:     QtDMM
// Description: Base class for multimter 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 <port.h>
#include <errno.h>

Port::Port() :
  m_handle( -1 )
{
}

Port::~Port()
{
}
  
Port::Error Port::writeByte( int byte ) const
{
  ssize_t retval;
  unsigned char cByte = byte;
  
  do
  {
    retval = ::write( m_handle, &cByte, 1 ); 
  }
  while (retval != -1 && retval != 1);
  
  if (retval < 0)
  {
    return errnoValue();
  }
  
  return Port::Ok;
}

Port::Error Port::readByte( int *byte ) const
{
  ssize_t retval;
  unsigned char cByte;
  
  do
  {
    retval = ::read( m_handle, &cByte, 1 ); 
  }
  while (retval != -1 && retval != 1);
  
  if (retval < 0)
  {
    return errnoValue();
  }
  
  *byte = cByte;
  
  return Port::Ok;
}
  
Port::Error Port::writeString( const char *string, ssize_t len ) const
{
  ssize_t retval;
  ssize_t remain = len;
  const char *data = string;
  
  do
  {
    retval = ::write( m_handle, data, remain ); 
    if (retval != -1) 
    {
      data += retval;
      remain -= retval;
    }
  }
  while (retval != -1 && remain);
  
  if (retval < 0)
  {
    return errnoValue();
  }
  
  return Port::Ok;
}

Port::Error Port::readString( char *string, ssize_t len ) const
{
  ssize_t retval;
  ssize_t remain = len;
  char *data = string;
  
  do
  {
    retval = ::read( m_handle, data, remain ); 
    if (retval != -1) 
    {
      data += retval;
      remain -= retval;
    }
  }
  while (retval != -1 && remain);

  if (retval < 0)
  {
    return errnoValue();
  }
  
  return Port::Ok;
}

Port::Error Port::errnoValue() const
{
  switch (errno)
  {
    case EAGAIN:
      return NoData;
    case EBADF:
      return BadFileDescriptor;
    case EFAULT:
      return BadAddress;
    case EINTR:
      return Interrupted;
    case EINVAL:
      return Invalid;
    case EIO:
      return IOError;
    case EISDIR:
      return IsDirectory;
  }
  
  return UnknownError;
}

const char *Port::errorString( Error err )
{
  switch (err)
  {
    case Ok:
      return "Ok";
    case SyntaxError:
      return "Syntax error";
    case PermissionDenied:
      return "Permission denied";
    case NoSuchPort:
      return "No such device";
    case ConfigError:
      return "Configuration error";
    case OpenError:
      return "Open error";
    case WriteError:
      return "Write error";
    case ReadError:
      return "Read error";
    case UnknownBaudRate:
      return "Unknown baud rate";
    case UnknownNumberOfBits:
      return "Unknown number of bits";
    case UnknownParity:
      return "Unknown parity";
    case UnknownStopBits:
      return "Unknown stop bits";
    case NoData:
      return "No data available";
    case BadFileDescriptor:
      return "Bad file descriptor";
    case BadAddress:
      return "Bad address";
    case Interrupted:
      return "Interrupted";
    case Invalid:
      return "Invalid device";
    case IOError:
      return "I/O error";
    case IsDirectory:
      return "File is directory";
    case UnknownError:
      return "Unknown error code";
  }
  
  return "Unknown error code";
}

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