A circular buffer. More...

#include <PlaybackSchedule.h>

Collaboration diagram for PlaybackSchedule::TimeQueue:

Classes
struct	Cursor

Public Member Functions
void	Producer (PlaybackSchedule &schedule, size_t nSamples)

double	Consumer (size_t nSamples, double rate)

void	Prime (double time)
	Empty the queue and reassign the last produced time. More...

Public Attributes
ArrayOf< double >	mData

size_t	mSize { 0 }

double	mLastTime {}

NonInterfering< Cursor >	mHead
	Aligned to avoid false sharing. More...

NonInterfering< Cursor >	mTail

Detailed Description

A circular buffer.

Definition at line 315 of file PlaybackSchedule.h.

Member Function Documentation

◆ Consumer()

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

Definition at line 397 of file PlaybackSchedule.cpp.

 {
    if ( ! mData ) {
       // 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;
    if ( nSamples >= space ) {
       remainder = 0,
       mHead.mIndex = (mHead.mIndex + 1) % mSize,
       nSamples -= space;
       if ( nSamples >= TimeQueueGrainSize )
          mHead.mIndex =
             (mHead.mIndex + ( nSamples / TimeQueueGrainSize ) ) % mSize,
          nSamples %= TimeQueueGrainSize;
    }
    mHead.mRemainder = remainder + nSamples;
    return mData[ mHead.mIndex ];
 }

References TimeQueueGrainSize.

Referenced by AudioIoCallback::UpdateTimePosition().

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◆ Prime()

void PlaybackSchedule::TimeQueue::Prime ( double time )

Empty the queue and reassign the last produced time.

Assumes the producer and consumer are suspended

Definition at line 421 of file PlaybackSchedule.cpp.

 {
    mHead = mTail = {};
    mLastTime = time;
 }

Referenced by AudioIoCallback::CallbackDoSeek().

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◆ Producer()

void PlaybackSchedule::TimeQueue::Producer	(	PlaybackSchedule &	schedule,
		size_t	nSamples
	)

Definition at line 356 of file PlaybackSchedule.cpp.

 {
    auto &policy = schedule.GetPolicy();
  
    if ( ! mData )
       // 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;
  
    while ( nSamples >= space ) {
       auto times = policy.AdvancedTrackTime( schedule, time, space );
       time = times.second;
       if (!std::isfinite(time))
          time = times.first;
       index = (index + 1) % mSize;
       mData[ index ] = time;
       nSamples -= space;
       remainder = 0;
       space = TimeQueueGrainSize;
    }
  
    // Last odd lot
    if ( nSamples > 0 ) {
       auto times = policy.AdvancedTrackTime( schedule, time, nSamples );
       time = times.second;
       if (!std::isfinite(time))
          time = times.first;
    }
  
    mLastTime = time;
    mTail.mRemainder = remainder + nSamples;
    mTail.mIndex = index;
 }