Carla/source/modules/juce_audio_devices/sources/juce_AudioTransportSource.cpp

/*
  ==============================================================================

   This file is part of the JUCE library.
   Copyright (c) 2016 - ROLI Ltd.

   Permission is granted to use this software 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.

   THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH REGARD
   TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
   FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT,
   OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
   USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
   TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
   OF THIS SOFTWARE.

   -----------------------------------------------------------------------------

   To release a closed-source product which uses other parts of JUCE not
   licensed under the ISC terms, commercial licenses are available: visit
   www.juce.com for more information.

  ==============================================================================
*/

AudioTransportSource::AudioTransportSource()
    : source (nullptr),
      resamplerSource (nullptr),
      bufferingSource (nullptr),
      positionableSource (nullptr),
      masterSource (nullptr),
      gain (1.0f),
      lastGain (1.0f),
      playing (false),
      stopped (true),
      sampleRate (44100.0),
      sourceSampleRate (0.0),
      blockSize (128),
      readAheadBufferSize (0),
      isPrepared (false),
      inputStreamEOF (false)
{
}

AudioTransportSource::~AudioTransportSource()
{
    setSource (nullptr);
    releaseMasterResources();
}

void AudioTransportSource::setSource (PositionableAudioSource* const newSource,
                                      int readAheadSize, TimeSliceThread* readAheadThread,
                                      double sourceSampleRateToCorrectFor, int maxNumChannels)
{
    if (source == newSource)
    {
        if (source == nullptr)
            return;

        setSource (nullptr, 0, nullptr); // deselect and reselect to avoid releasing resources wrongly
    }

    readAheadBufferSize = readAheadSize;
    sourceSampleRate = sourceSampleRateToCorrectFor;

    ResamplingAudioSource* newResamplerSource = nullptr;
    BufferingAudioSource* newBufferingSource = nullptr;
    PositionableAudioSource* newPositionableSource = nullptr;
    AudioSource* newMasterSource = nullptr;

    ScopedPointer<ResamplingAudioSource> oldResamplerSource (resamplerSource);
    ScopedPointer<BufferingAudioSource> oldBufferingSource (bufferingSource);
    AudioSource* oldMasterSource = masterSource;

    if (newSource != nullptr)
    {
        newPositionableSource = newSource;

        if (readAheadSize > 0)
        {
            // If you want to use a read-ahead buffer, you must also provide a TimeSliceThread
            // for it to use!
            jassert (readAheadThread != nullptr);

            newPositionableSource = newBufferingSource
                = new BufferingAudioSource (newPositionableSource, *readAheadThread,
                                            false, readAheadSize, maxNumChannels);
        }

        newPositionableSource->setNextReadPosition (0);

        if (sourceSampleRateToCorrectFor > 0)
            newMasterSource = newResamplerSource
                = new ResamplingAudioSource (newPositionableSource, false, maxNumChannels);
        else
            newMasterSource = newPositionableSource;

        if (isPrepared)
        {
            if (newResamplerSource != nullptr && sourceSampleRate > 0 && sampleRate > 0)
                newResamplerSource->setResamplingRatio (sourceSampleRate / sampleRate);

            newMasterSource->prepareToPlay (blockSize, sampleRate);
        }
    }

    {
        const ScopedLock sl (callbackLock);

        source = newSource;
        resamplerSource = newResamplerSource;
        bufferingSource = newBufferingSource;
        masterSource = newMasterSource;
        positionableSource = newPositionableSource;

        inputStreamEOF = false;
        playing = false;
    }

    if (oldMasterSource != nullptr)
        oldMasterSource->releaseResources();
}

void AudioTransportSource::start()
{
    if ((! playing) && masterSource != nullptr)
    {
        {
            const ScopedLock sl (callbackLock);
            playing = true;
            stopped = false;
            inputStreamEOF = false;
        }

        sendChangeMessage();
    }
}

void AudioTransportSource::stop()
{
    if (playing)
    {
        {
            const ScopedLock sl (callbackLock);
            playing = false;
        }

        int n = 500;
        while (--n >= 0 && ! stopped)
            Thread::sleep (2);

        sendChangeMessage();
    }
}

void AudioTransportSource::setPosition (double newPosition)
{
    if (sampleRate > 0.0)
        setNextReadPosition ((int64) (newPosition * sampleRate));
}

double AudioTransportSource::getCurrentPosition() const
{
    if (sampleRate > 0.0)
        return getNextReadPosition() / sampleRate;

    return 0.0;
}

double AudioTransportSource::getLengthInSeconds() const
{
    if (sampleRate > 0.0)
        return getTotalLength() / sampleRate;

    return 0.0;
}

void AudioTransportSource::setNextReadPosition (int64 newPosition)
{
    if (positionableSource != nullptr)
    {
        if (sampleRate > 0 && sourceSampleRate > 0)
            newPosition = (int64) (newPosition * sourceSampleRate / sampleRate);

        positionableSource->setNextReadPosition (newPosition);

        if (resamplerSource != nullptr)
            resamplerSource->flushBuffers();

        inputStreamEOF = false;
    }
}

int64 AudioTransportSource::getNextReadPosition() const
{
    if (positionableSource != nullptr)
    {
        const double ratio = (sampleRate > 0 && sourceSampleRate > 0) ? sampleRate / sourceSampleRate : 1.0;
        return (int64) (positionableSource->getNextReadPosition() * ratio);
    }

    return 0;
}

int64 AudioTransportSource::getTotalLength() const
{
    const ScopedLock sl (callbackLock);

    if (positionableSource != nullptr)
    {
        const double ratio = (sampleRate > 0 && sourceSampleRate > 0) ? sampleRate / sourceSampleRate : 1.0;
        return (int64) (positionableSource->getTotalLength() * ratio);
    }

    return 0;
}

bool AudioTransportSource::isLooping() const
{
    const ScopedLock sl (callbackLock);
    return positionableSource != nullptr && positionableSource->isLooping();
}

void AudioTransportSource::setGain (const float newGain) noexcept
{
    gain = newGain;
}

void AudioTransportSource::prepareToPlay (int samplesPerBlockExpected, double newSampleRate)
{
    const ScopedLock sl (callbackLock);

    sampleRate = newSampleRate;
    blockSize = samplesPerBlockExpected;

    if (masterSource != nullptr)
        masterSource->prepareToPlay (samplesPerBlockExpected, sampleRate);

    if (resamplerSource != nullptr && sourceSampleRate > 0)
        resamplerSource->setResamplingRatio (sourceSampleRate / sampleRate);

    inputStreamEOF = false;
    isPrepared = true;
}

void AudioTransportSource::releaseMasterResources()
{
    const ScopedLock sl (callbackLock);

    if (masterSource != nullptr)
        masterSource->releaseResources();

    isPrepared = false;
}

void AudioTransportSource::releaseResources()
{
    releaseMasterResources();
}

void AudioTransportSource::getNextAudioBlock (const AudioSourceChannelInfo& info)
{
    const ScopedLock sl (callbackLock);

    if (masterSource != nullptr && ! stopped)
    {
        masterSource->getNextAudioBlock (info);

        if (! playing)
        {
            // just stopped playing, so fade out the last block..
            for (int i = info.buffer->getNumChannels(); --i >= 0;)
                info.buffer->applyGainRamp (i, info.startSample, jmin (256, info.numSamples), 1.0f, 0.0f);

            if (info.numSamples > 256)
                info.buffer->clear (info.startSample + 256, info.numSamples - 256);
        }

        if (positionableSource->getNextReadPosition() > positionableSource->getTotalLength() + 1
              && ! positionableSource->isLooping())
        {
            playing = false;
            inputStreamEOF = true;
            sendChangeMessage();
        }

        stopped = ! playing;

        for (int i = info.buffer->getNumChannels(); --i >= 0;)
            info.buffer->applyGainRamp (i, info.startSample, info.numSamples, lastGain, gain);
    }
    else
    {
        info.clearActiveBufferRegion();
        stopped = true;
    }

    lastGain = gain;
}