realtime_box.h

// Copyright (c) 2009, Willow Garage, Inc.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
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//    * Redistributions in binary form must reproduce the above copyright
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//      this software without specific prior written permission.
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// Author: Stuart Glaser
 
#ifndef REALTIME_TOOLS__REALTIME_BOX_H__
#define REALTIME_TOOLS__REALTIME_BOX_H__
 
#include <mutex>
#include <string>
 
namespace realtime_tools
{
template <class T>
class RealtimeBox
{
public:
  explicit RealtimeBox(const T & initial = T()) : thing_(initial) {}
 
  void set(const T & value)
  {
    std::lock_guard<std::mutex> guard(thing_lock_RT_);
    thing_ = value;
  }
 
  void get(T & ref)
  {
    std::lock_guard<std::mutex> guard(thing_lock_RT_);
    ref = thing_;
  }
 
private:
  // The thing that's in the box.
  T thing_;
 
  // Protects access to the thing in the box.  This mutex is
  // guaranteed to be locked for no longer than the duration of the
  // copy, so as long as the copy is realtime safe and the OS has
  // priority inheritance for mutexes, this lock can be safely locked
  // from within realtime.
  std::mutex thing_lock_RT_;
};
 
}  // namespace realtime_tools
 
#endif  // REALTIME_TOOLS__REALTIME_BOX_H_