126 lines
3.8 KiB
C++
126 lines
3.8 KiB
C++
/*
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TICK-SERVICE.hpp - issuing timed callbacks
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Copyright (C) Lumiera.org
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2009, Joel Holdsworth <joel@airwebreathe.org.uk>,
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Hermann Vosseler <Ichthyostega@web.de>
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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/** @file tick-service.hpp
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** A timer service invoking a given callback periodically.
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** This is a rough preliminary implementation as of 1/2009. We use it to
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** drive the frame "creation" of a player dummy (the render engine is not
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** ready yet). The intention is to make this a real service later on, which
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** might consolidate and sync various ongoing output processes to a common
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** beat, which it implements by precision posix timers. Probably then this
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** service will become part of the backend, or rely on a timing service.
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**
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** @see proc::play::DummyPlayerService
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**
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*/
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#ifndef PROC_PLAY_TICKSERVICE_H
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#define PROC_PLAY_TICKSERVICE_H
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#include "backend/thread-wrapper.hpp"
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#include <tr1/functional>
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#include <limits>
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namespace proc {
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namespace play {
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using std::tr1::function;
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/************************************************************
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* Tick generating service for a periodic callback,
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* with adjustable frequency. Quick'n dirty implementation!
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*/
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class TickService
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: backend::Thread
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{
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typedef function<void(void)> Tick;
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volatile uint timespan_;
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/** poll interval for new settings in wait state */
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static const uint POLL_TIMEOUT = 1000;
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public:
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TickService (Tick callback)
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: Thread("Tick generator (dummy)",
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bind (&TickService::timerLoop, this, callback))
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{
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INFO (proc, "TickService started.");
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}
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~TickService ()
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{
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uint curr_tick = timespan_;
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timespan_ = 0;
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usleep (2*curr_tick); ////TODO actually should wait for timer thread termination
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INFO (proc, "TickService shutdown.");
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}
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/** set the periodic timer to run with a given frequency,
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* starting \em now. Well, not actually now, but at the next
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* opportunity. It should be \em now, but this implementation
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* is sloppy! setting fps==0 halts (pauses) the timer.
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*/
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void activate (uint fps)
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{
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REQUIRE ( 0==fps
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|| 1000000/fps < std::numeric_limits<uint>::max()
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&& 1000000/fps > POLL_TIMEOUT);
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if (fps)
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timespan_ = 1000000/fps; // microseconds per tick
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else
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timespan_ = POLL_TIMEOUT;
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}
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private:
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void timerLoop(Tick periodicFun)
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{
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timespan_ = POLL_TIMEOUT;
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while (0 < timespan_)
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{
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if (timespan_ > POLL_TIMEOUT)
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periodicFun();
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usleep (timespan_);
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}
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TRACE (proc_dbg, "Tick Thread timer loop exiting...");
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}
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};
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} // namespace play
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} // namespace proc
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#endif // PROC_PLAY_TICKSERVICE_H
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