juce_BufferingAudioSource.h

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/*
  ==============================================================================
 
   This file is part of the JUCE library.
   Copyright (c) 2022 - Raw Material Software Limited
 
   JUCE is an open source library subject to commercial or open-source
   licensing.
 
   The code included in this file is provided under the terms of the ISC license
   http://www.isc.org/downloads/software-support-policy/isc-license. Permission
   To use, copy, modify, and/or distribute this software for any purpose with or
   without fee is hereby granted provided that the above copyright notice and
   this permission notice appear in all copies.
 
   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.
 
  ==============================================================================
*/
 
namespace juce
{
 
//==============================================================================
class JUCE_API  BufferingAudioSource  : public PositionableAudioSource,
                                        private TimeSliceClient
{
public:
    //==============================================================================
    BufferingAudioSource (PositionableAudioSource* source,
                          TimeSliceThread& backgroundThread,
                          bool deleteSourceWhenDeleted,
                          int numberOfSamplesToBuffer,
                          int numberOfChannels = 2,
                          bool prefillBufferOnPrepareToPlay = true);

    ~BufferingAudioSource() override;
 
    //==============================================================================
    void prepareToPlay (int samplesPerBlockExpected, double sampleRate) override;

    void releaseResources() override;

    void getNextAudioBlock (const AudioSourceChannelInfo&) override;
 
    //==============================================================================
    void setNextReadPosition (int64 newPosition) override;

    int64 getNextReadPosition() const override;

    int64 getTotalLength() const override       { return source->getTotalLength(); }

    bool isLooping() const override             { return source->isLooping(); }

    bool waitForNextAudioBlockReady (const AudioSourceChannelInfo& info, const uint32 timeout);
 
private:
    //==============================================================================
    Range<int> getValidBufferRange (int numSamples) const;
    bool readNextBufferChunk();
    void readBufferSection (int64 start, int length, int bufferOffset);
    int useTimeSlice() override;
 
    //==============================================================================
    OptionalScopedPointer<PositionableAudioSource> source;
    TimeSliceThread& backgroundThread;
    int numberOfSamplesToBuffer, numberOfChannels;
    AudioBuffer<float> buffer;
    CriticalSection callbackLock, bufferRangeLock;
    WaitableEvent bufferReadyEvent;
    int64 bufferValidStart = 0, bufferValidEnd = 0;
    std::atomic<int64> nextPlayPos { 0 };
    double sampleRate = 0;
    bool wasSourceLooping = false, isPrepared = false;
    const bool prefillBuffer;
 
    //==============================================================================
    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (BufferingAudioSource)
};
 
} // namespace juce