realtime_clock.h

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/*
 * Copyright (c) 2013 hiDOF, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the Willow Garage, Inc. nor the names of its
 *       contributors may be used to endorse or promote products derived from
 *       this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
 
/*
 * Publishing ROS messages is difficult, as the publish function is
 * not realtime safe.  This class provides the proper locking so that
 * you can call publish in realtime and a separate (non-realtime)
 * thread will ensure that the message gets published over ROS.
 *
 * Author: Wim Meeussen
 */
 
#ifndef REALTIME_TOOLS__REALTIME_CLOCK_H_
#define REALTIME_TOOLS__REALTIME_CLOCK_H_
 
#include <ros/ros.h>
 
#include <mutex>
#include <thread>
 
namespace realtime_tools
{
 
class RealtimeClock
{
 public:
  RealtimeClock();
  ~RealtimeClock();
 
  ros::Time getSystemTime(const ros::Time& realtime_time);
  void loop();
 
 
 private:
  unsigned int lock_misses_ = 0;
  ros::Time system_time_;
  ros::Duration clock_offset_;
 
  ros::Time last_realtime_time_;
  bool running_ = false;
  bool initialized_ = false;
  std::mutex mutex_;
  std::thread thread_;
 
 
 
}; // class
}// namespace
 
#endif