/*
    Copyright (C) 2017-2021 Carl Hetherington <cth@carlh.net>

    This file is part of DCP-o-matic.

    DCP-o-matic 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 2 of the License, or
    (at your option) any later version.

    DCP-o-matic 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.

    You should have received a copy of the GNU General Public License
    along with DCP-o-matic.  If not, see <http://www.gnu.org/licenses/>.

*/


#ifndef DCPOMATIC_EVENT_HISTORY_H
#define DCPOMATIC_EVENT_HISTORY_H


#include <boost/optional.hpp>
#include <boost/thread/mutex.hpp>
#include <list>


class EventHistory
{
public:
	explicit EventHistory(int size);

	boost::optional<float> rate() const;
	void event();
	int events() const;

private:
	/** Mutex for _history and _events */
	mutable boost::mutex _mutex;
	/** List of the times of the last _history_size events
	    first is the most recently completed.
	*/
	std::list<struct timeval> _history;
	int _events = 0;
	/** Number of events that we should keep history for */
	int const _size;
};


#endif