text: /*
    ==============================================================================
  
     This file is part of the JUCE library.
     Copyright (c) 2020 - 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
  {
  
  AudioTransportSource::AudioTransportSource()
  {
  }
  
  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;
  
      std::unique_ptr<ResamplingAudioSource> oldResamplerSource (resamplerSource);
      std::unique_ptr<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)
      {
          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 (double) getNextReadPosition() / sampleRate;
  
      return 0.0;
  }
  
  double AudioTransportSource::getLengthInSeconds() const
  {
      if (sampleRate > 0.0)
          return (double) getTotalLength() / sampleRate;
  
      return 0.0;
  }
  
  void AudioTransportSource::setNextReadPosition (int64 newPosition)
  {
      if (positionableSource != nullptr)
      {
          if (sampleRate > 0 && sourceSampleRate > 0)
              newPosition = (int64) ((double) 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) ((double) 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) ((double) 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;
  }
  
  } // namespace juce
  