PlaybackSchedule::TimeQueue Class Reference

A circular buffer. More...

#include <PlaybackSchedule.h>

Collaboration diagram for PlaybackSchedule::TimeQueue:

Classes
struct	Cursor
struct	Record

Public Member Functions
void	Clear ()
void	Resize (size_t size)
void	Producer (PlaybackSchedule &schedule, PlaybackSlice slice)
	Enqueue track time value advanced by the slice according to schedule's PlaybackPolicy. More...
double	GetLastTime () const
	Return the last time saved by Producer. More...
void	SetLastTime (double time)
double	Consumer (size_t nSamples, double rate)
	Find the track time value nSamples after the last consumed sample. More...
void	Prime (double time)
	Empty the queue and reassign the last produced time. More...

Private Types
using	Records = std::vector< Record >

Private Attributes
Records	mData
double	mLastTime {}
NonInterfering< Cursor >	mHead
	Aligned to avoid false sharing. More...
NonInterfering< Cursor >	mTail

Detailed Description

A circular buffer.

Definition at line 209 of file PlaybackSchedule.h.

Member Typedef Documentation

Records

using PlaybackSchedule::TimeQueue::Records = std::vector<Record>

private

Definition at line 243 of file PlaybackSchedule.h.

Member Function Documentation

Clear()

void PlaybackSchedule::TimeQueue::Clear

(

)

by main thread

Definition at line 268 of file PlaybackSchedule.cpp.

{
   mData = Records{};
   mHead = {};
   mTail = {};
}

References mData, mHead, and mTail.

Referenced by AudioIO::StartStream(), AudioIO::StartStreamCleanup(), and AudioIO::StopStream().

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Consumer()

double PlaybackSchedule::TimeQueue::Consumer	(	size_t	nSamples,
		double	rate
	)

Find the track time value nSamples after the last consumed sample.

by main thread

Definition at line 345 of file PlaybackSchedule.cpp.

{
   if ( mData.empty() ) {
      // Recording only.  No scrub or playback time warp.  Don't use the queue.
      return ( mLastTime += nSamples / rate );
   }
 
   // Don't check available space:  assume it is enough because of coordination
   // with RingBuffer.
   auto remainder = mHead.mRemainder;
   auto space = TimeQueueGrainSize - remainder;
   const auto size = mData.size();
   if ( nSamples >= space ) {
      remainder = 0,
      mHead.mIndex = (mHead.mIndex + 1) % size,
      nSamples -= space;
      if ( nSamples >= TimeQueueGrainSize )
         mHead.mIndex =
            (mHead.mIndex + ( nSamples / TimeQueueGrainSize ) ) % size,
         nSamples %= TimeQueueGrainSize;
   }
   mHead.mRemainder = remainder + nSamples;
   return mData[ mHead.mIndex ].timeValue;
}

References size, and TimeQueueGrainSize.

Referenced by AudioIoCallback::UpdateTimePosition().

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GetLastTime()

double PlaybackSchedule::TimeQueue::GetLastTime

(

)

const

Return the last time saved by Producer.

Definition at line 335 of file PlaybackSchedule.cpp.

{
   return mLastTime;
}

Referenced by DefaultPlaybackPolicy::RepositionPlayback(), and DefaultPlaybackPolicy::RevertToOldDefault().

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Prime()

void PlaybackSchedule::TimeQueue::Prime

(

double

time

)

Empty the queue and reassign the last produced time.

by main thread

Assumes producer and consumer are suspended

Definition at line 370 of file PlaybackSchedule.cpp.

{
   mHead = mTail = {};
   mLastTime = time;
   if ( !mData.empty() )
      mData[0].timeValue = time;
}

Referenced by AudioIoCallback::CallbackDoSeek(), and AudioIO::StartStream().

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Producer()

void PlaybackSchedule::TimeQueue::Producer	(	PlaybackSchedule &	schedule,
		PlaybackSlice	slice
	)

Enqueue track time value advanced by the slice according to schedule's PlaybackPolicy.

by the main thread

Definition at line 280 of file PlaybackSchedule.cpp.

{
   auto &policy = schedule.GetPolicy();
 
   if ( mData.empty() )
      // Recording only.  Don't fill the queue.
      return;
 
   // Don't check available space:  assume it is enough because of coordination
   // with RingBuffer.
   auto index = mTail.mIndex;
   auto time = mLastTime;
   auto remainder = mTail.mRemainder;
   auto space = TimeQueueGrainSize - remainder;
   const auto size = mData.size();
 
   // Produce advancing times
   auto frames = slice.toProduce;
   while ( frames >= space ) {
      auto times = policy.AdvancedTrackTime( schedule, time, space );
      time = times.second;
      if (!std::isfinite(time))
         time = times.first;
      index = (index + 1) % size;
      mData[ index ].timeValue = time;
      frames -= space;
      remainder = 0;
      space = TimeQueueGrainSize;
   }
   // Last odd lot
   if ( frames > 0 ) {
      auto times = policy.AdvancedTrackTime( schedule, time, frames );
      time = times.second;
      if (!std::isfinite(time))
         time = times.first;
      remainder += frames;
      space -= frames;
   }
 
   // Produce constant times if there is also some silence in the slice
   frames = slice.frames - slice.toProduce;
   while ( frames > 0 && frames >= space ) {
      index = (index + 1) % size;
      mData[ index ].timeValue = time;
      frames -= space;
      remainder = 0;
      space = TimeQueueGrainSize;
   }
 
   mLastTime = time;
   mTail.mRemainder = remainder + frames;
   mTail.mIndex = index;
}

References PlaybackSlice::frames, PlaybackSchedule::GetPolicy(), size, TimeQueueGrainSize, and PlaybackSlice::toProduce.

Referenced by AudioIO::ProcessPlaybackSlices().

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Resize()

void PlaybackSchedule::TimeQueue::Resize

(

size_t

size

)

Definition at line 275 of file PlaybackSchedule.cpp.

{
   mData.resize(size);
}

References size.

Referenced by AudioIO::AllocateBuffers().

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SetLastTime()

void PlaybackSchedule::TimeQueue::SetLastTime

(

double

time

)

Definition at line 340 of file PlaybackSchedule.cpp.

{
   mLastTime = time;
}

Referenced by DefaultPlaybackPolicy::RepositionPlayback().

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Member Data Documentation

mData

Records PlaybackSchedule::TimeQueue::mData

private

Definition at line 244 of file PlaybackSchedule.h.

Referenced by Clear().

mHead

NonInterfering<Cursor> PlaybackSchedule::TimeQueue::mHead

private

Aligned to avoid false sharing.

Definition at line 251 of file PlaybackSchedule.h.

Referenced by Clear().

mLastTime

double PlaybackSchedule::TimeQueue::mLastTime {}

private

Definition at line 245 of file PlaybackSchedule.h.

mTail

NonInterfering<Cursor> PlaybackSchedule::TimeQueue::mTail

private

Definition at line 251 of file PlaybackSchedule.h.

Referenced by Clear().

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The documentation for this class was generated from the following files:

• PlaybackSchedule.h
• PlaybackSchedule.cpp