joystick.cpp

// 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 3 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.

#include "joystick.h"

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <iostream>
#include <string>
#include <sstream>
#include "unistd.h"

Joystick::Joystick()
{
  openPath("/dev/input/js0");
}

Joystick::Joystick(int joystickNumber)
{
  std::stringstream sstm;
  sstm << "/dev/input/js" << joystickNumber;
  openPath(sstm.str());
}

Joystick::Joystick(std::string devicePath)
{
  openPath(devicePath);
}

void Joystick::openPath(std::string devicePath)
{
  _fd = open(devicePath.c_str(), O_RDONLY | O_NONBLOCK);
}

bool Joystick::sample(JoystickEvent* event)
{
  int bytes = read(_fd, event, sizeof(*event)); 

  if (bytes == -1)
    return false;

  // NOTE if this condition is not met, we're probably out of sync and this
  // Joystick instance is likely unusable
  return bytes == sizeof(*event);
}

bool Joystick::isFound()
{
  return _fd >= 0;
}

Joystick::~Joystick()
{
  close(_fd);
};