StretchingSequence.h

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/*  SPDX-License-Identifier: GPL-2.0-or-later */
/*!********************************************************************
 
  Audacity: A Digital Audio Editor
 
  StretchingSequence.h
 
  Matthieu Hodgkinson
 
**********************************************************************/
#pragma once
 
#include "AudioIOSequences.h"
#include "PlaybackDirection.h"
 
#include <memory>
#include <optional>
#include <vector>
 
class AudioSegment;
class AudioSegmentFactoryInterface;
class ClipInterface;
using ClipConstHolders = std::vector<std::shared_ptr<const ClipInterface>>;
 
// For now this class assumes forward reading, which will be sufficient for the
// first goal of allowing export and rendering.
class STRETCHING_SEQUENCE_API StretchingSequence final : public PlayableSequence
{
public:
   static std::shared_ptr<StretchingSequence>
   Create(const PlayableSequence&, const ClipConstHolders& clips);
 
   StretchingSequence(
      const PlayableSequence&, int sampleRate, size_t numChannels,
      std::unique_ptr<AudioSegmentFactoryInterface>);
 
   // WideSampleSequence
   size_t NChannels() const override;
   float GetChannelVolume(int channel) const override;
   double GetStartTime() const override;
   double GetEndTime() const override;
   double GetRate() const override;
   sampleFormat WidestEffectiveFormat() const override;
   bool HasTrivialEnvelope() const override;
   void GetEnvelopeValues(
      double* buffer, size_t bufferLen, double t0,
      bool backwards) const override;
   bool DoGet(
      size_t iChannel, size_t nBuffers, const samplePtr buffers[],
      sampleFormat format, sampleCount start, size_t len, bool backwards,
      fillFormat fill = FillFormat::fillZero, bool mayThrow = true,
      sampleCount* pNumWithinClips = nullptr) const override;
 
   // PlayableSequence
   const ChannelGroup *FindChannelGroup() const override;
   bool GetSolo() const override;
   bool GetMute() const override;
 
   // AudioGraph::Channel
   AudioGraph::ChannelType GetChannelType() const override;
 
   // class methods
   bool GetFloats(
      float* buffers[], sampleCount start, size_t len, bool backwards) const;
 
private:
   using AudioSegments = std::vector<std::shared_ptr<AudioSegment>>;
 
   void ResetCursor(double t, PlaybackDirection);
   bool GetNext(float *const buffers[], size_t numChannels, size_t numSamples);
   bool MutableGet(
      size_t iChannel, size_t nBuffers, const samplePtr buffers[],
      sampleFormat format, sampleCount start, size_t len, bool backwards);
 
   const PlayableSequence& mSequence;
   const std::unique_ptr<AudioSegmentFactoryInterface> mAudioSegmentFactory;
   AudioSegments mAudioSegments;
   AudioSegments::const_iterator mActiveAudioSegmentIt = mAudioSegments.end();
   std::optional<sampleCount> mExpectedStart;
   PlaybackDirection mPlaybackDirection = PlaybackDirection::forward;
};