    //------------------------------------------------------------------------------
    // emTimer.h
    //
    // Copyright (C) 2006-2008,2010,2016 Oliver Hamann.
    //
    // Homepage: http://eaglemode.sourceforge.net/
    //
    // This program is free software: you can redistribute it and/or modify it under
    // the terms of the GNU General Public License version 3 as published by the
    // Free Software Foundation.
    //
    // 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 version 3 for
    // more details.
    //
    // You should have received a copy of the GNU General Public License version 3
    // along with this program. If not, see <http://www.gnu.org/licenses/>.
    //------------------------------------------------------------------------------

    #ifndef emTimer_h
    #define emTimer_h

    #ifndef emEngine_h
    #include <emCore/emEngine.h>
    #endif

    //==============================================================================
    //================================== emTimer ===================================
    //==============================================================================

    class emTimer : public emUncopyable {

    public:

            // Class for a timer which signals an emSignal on each timer event.

            emTimer(emScheduler & scheduler);
                    // Construct a timer. The given scheduler is used for signaling
                    // the timer signal (and for an internal engine which serves all
                    // the timers on that scheduler).

            virtual ~emTimer();
                    // Destructor.

            emScheduler & GetScheduler() const;
                    // Get the scheduler.

            const emSignal & GetSignal() const;
                    // This signal is signaled on each timer event.

            void Start(emUInt64 millisecs, bool periodic=false);
                    // Start the timer.
                    // Arguments:
                    //   millisecs - Time in milliseconds after which a timer event
                    //               shall be generated.
                    //   periodic  - If true, additional timer events are generated
                    //               periodically. The given number of milliseconds
                    //               is the period duration. The timer tries to keep
                    //               up that rate on average, even if timer events
                    //               are delayed through blockings of the scheduler,
                    //               but it is limited to the rate of scheduler time
                    //               slices by all means.

            bool IsRunning() const;
                    // Ask whether the timer is still active.

            void Stop(bool abortSignal);
                    // Stop the timer.
                    // Arguments:
                    //   abortSignal - Whether to perform an Abort() on the signal,
                    //                 but remember that engines could already have
                    //                 been woken up. Say false for an asynchronous
                    //                 stop, or true for a synchronous stop.

    private:

            struct TimeNode {
                    emUInt64 SigTime;
                    TimeNode * Prev;
                    TimeNode * Next;
            };

            class TimerCentral : public emEngine {
            public:
                    TimerCentral(emScheduler & scheduler);
                    void Insert(TimeNode * node, emUInt64 sigTime);
                    int RefCount;
            protected:
                    virtual bool Cycle();
            private:
                    TimeNode InList;
                    TimeNode OutList;
                    bool Busy;
            };

            friend class TimerCentral;

            TimerCentral * Central;
            emSignal TimerSignal;
            emUInt64 Period;
            TimeNode Node;
    };

    inline emScheduler & emTimer::GetScheduler() const
    {
            return Central->GetScheduler();
    }

    inline const emSignal & emTimer::GetSignal() const
    {
            return TimerSignal;
    }

    inline bool emTimer::IsRunning() const
    {
            return Node.Prev!=NULL;
    }

    #endif