timings.cpp

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/*
  Timings  -  timing specifications for a frame quantised data stream

  Copyright (C)         Lumiera.org
    2012,               Hermann Vosseler <Ichthyostega@web.de>

  This program 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.

  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 for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

* *****************************************************/


#include "steam/play/timings.hpp"
#include "lib/time/formats.hpp"
#include "lib/time/timequant.hpp"
#include "lib/rational.hpp"


namespace steam {
namespace play {
  
  using lib::time::PQuant;
  using lib::time::Time;
  using lib::time::TimeVar;
  using lib::time::FrameCnt;
  using lib::time::FSecs;
  
  namespace { // Hard wired placeholder settings...
    
    const Duration DEFAULT_ENGINE_LATENCY  = Duration{Time{10,0}};    
    const Duration DEFAULT_JOB_PLANNING_TURNOVER(FSecs(3,2));
    
  }//(End)hard wired settings
  
  
  namespace { // hidden local details of the service implementation....
    
    inline PQuant
    buildStandardGridForFramerate (FrameRate fps)
    {
      return PQuant (new lib::time::FixedFrameQuantiser (fps));
    }                         
    
  } // (End) hidden service impl details
  
  
  
  Timings::Timings (FrameRate fps)
    : grid_{buildStandardGridForFramerate(fps)}
    , playbackUrgency {ASAP}
    , playbackSpeed {1}
    , scheduledDelivery{Time::NEVER}
    , outputLatency{Duration::NIL}
    , engineLatency{DEFAULT_ENGINE_LATENCY}    
    { 
      ENSURE (grid_);
    }
  
  Timings::Timings (FrameRate fps, Time realTimeAnchor)
    : grid_{buildStandardGridForFramerate(fps)}
    , playbackUrgency {TIMEBOUND}
    , playbackSpeed {1}
    , scheduledDelivery{realTimeAnchor}
    , outputLatency {Duration::NIL}
    , engineLatency{DEFAULT_ENGINE_LATENCY}
    {
      ENSURE (grid_);
    }
  
  
  
  Timings Timings::DISABLED(FrameRate::HALTED);
  
  
  
  bool
  Timings::isValid()  const
  {
    return bool(grid_)
        && (( (ASAP == playbackUrgency || NICE == playbackUrgency)
            && Time::NEVER == scheduledDelivery)
           ||
            (TIMEBOUND == playbackUrgency
            && Time::MIN < scheduledDelivery && scheduledDelivery < Time::MAX)
           );
  }
  
  Time
  Timings::getOrigin()  const
  {
    return Time(grid_->timeOf(0));
  }
  
  
  Time
  Timings::getFrameStartAt (FrameCnt frameNr)  const
  {
    return Time(grid_->timeOf(frameNr));
  }
  
  
  Duration
  Timings::getFrameDurationAt (TimeValue refPoint)  const
  {
    FrameCnt frameNr = grid_->gridPoint (refPoint);
    return getFrameDurationAt(frameNr);
  }
  
  
  Duration
  Timings::getFrameDurationAt (FrameCnt refFrameNr)  const
  {
    return Offset (grid_->timeOf(refFrameNr), grid_->timeOf(refFrameNr + 1));
  }
  
  
  FrameCnt
  Timings::getBreakPointAfter (TimeValue refPoint)  const
  {
    FrameCnt frameNr = grid_->gridPoint (refPoint);
    return grid_->timeOf(frameNr) == refPoint? frameNr
                                             : frameNr+1;
  }
  
  
                                    
  Duration
  Timings::constantFrameTimingsInterval (TimeValue)  const
  {
    return Duration (Time::MAX);
  }
  
  
  Time
  Timings::getTimeDue(FrameCnt frameOffset)  const
  {
    if (TIMEBOUND == playbackUrgency)
      {
        REQUIRE (scheduledDelivery != Time::NEVER);
        return scheduledDelivery
             + getRealOffset (frameOffset);
      }
    else
      return Time::NEVER;
  }
  
  
  Offset
  Timings::getRealOffset (FrameCnt frameOffset)  const
  {
    Offset nominalOffset (grid_->timeOf(0), grid_->timeOf(frameOffset));
    return isOriginalSpeed()? nominalOffset
                            : nominalOffset * playbackSpeed;
  }
  
  
  Duration
  Timings::getPlanningChunkDuration()  const
  {
    UNIMPLEMENTED ("controlling the job planning rhythm");
  }
  
  
  FrameCnt
  Timings::establishNextPlanningChunkStart(FrameCnt anchorFrame)  const
  {
    TimeVar breakingPoint = grid_->timeOf(anchorFrame);
    breakingPoint += getPlanningChunkDuration();
    FrameCnt nextFrame = grid_->gridPoint (breakingPoint);
    
    ASSERT (breakingPoint <= grid_->timeOf(nextFrame));
    ASSERT (breakingPoint >  grid_->timeOf(nextFrame-1));
    
    if (grid_->timeOf(nextFrame) == breakingPoint)
      return nextFrame;
    else
      return nextFrame+1;
  }
  
  
  
  Timings
  Timings::constrainedBy (Timings additionalConditions)
  {
    UNIMPLEMENTED ("how to combine timing constraints");
  }
  
  
  
}} // namespace steam::play