Carla/source/modules/juce_audio_devices/sources/juce_AudioSourcePlayer.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.

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

AudioSourcePlayer::AudioSourcePlayer()
    : source (nullptr),
      sampleRate (0),
      bufferSize (0),
      lastGain (1.0f),
      gain (1.0f)
{
}

AudioSourcePlayer::~AudioSourcePlayer()
{
    setSource (nullptr);
}

void AudioSourcePlayer::setSource (AudioSource* newSource)
{
    if (source != newSource)
    {
        AudioSource* const oldSource = source;

        if (newSource != nullptr && bufferSize > 0 && sampleRate > 0)
            newSource->prepareToPlay (bufferSize, sampleRate);

        {
            const ScopedLock sl (readLock);
            source = newSource;
        }

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

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

void AudioSourcePlayer::audioDeviceIOCallback (const float** inputChannelData,
                                               int totalNumInputChannels,
                                               float** outputChannelData,
                                               int totalNumOutputChannels,
                                               int numSamples)
{
    // these should have been prepared by audioDeviceAboutToStart()...
    jassert (sampleRate > 0 && bufferSize > 0);

    const ScopedLock sl (readLock);

    if (source != nullptr)
    {
        int numActiveChans = 0, numInputs = 0, numOutputs = 0;

        // messy stuff needed to compact the channels down into an array
        // of non-zero pointers..
        for (int i = 0; i < totalNumInputChannels; ++i)
        {
            if (inputChannelData[i] != nullptr)
            {
                inputChans [numInputs++] = inputChannelData[i];
                if (numInputs >= numElementsInArray (inputChans))
                    break;
            }
        }

        for (int i = 0; i < totalNumOutputChannels; ++i)
        {
            if (outputChannelData[i] != nullptr)
            {
                outputChans [numOutputs++] = outputChannelData[i];
                if (numOutputs >= numElementsInArray (outputChans))
                    break;
            }
        }

        if (numInputs > numOutputs)
        {
            // if there aren't enough output channels for the number of
            // inputs, we need to create some temporary extra ones (can't
            // use the input data in case it gets written to)
            tempBuffer.setSize (numInputs - numOutputs, numSamples,
                                false, false, true);

            for (int i = 0; i < numOutputs; ++i)
            {
                channels[numActiveChans] = outputChans[i];
                memcpy (channels[numActiveChans], inputChans[i], sizeof (float) * (size_t) numSamples);
                ++numActiveChans;
            }

            for (int i = numOutputs; i < numInputs; ++i)
            {
                channels[numActiveChans] = tempBuffer.getWritePointer (i - numOutputs);
                memcpy (channels[numActiveChans], inputChans[i], sizeof (float) * (size_t) numSamples);
                ++numActiveChans;
            }
        }
        else
        {
            for (int i = 0; i < numInputs; ++i)
            {
                channels[numActiveChans] = outputChans[i];
                memcpy (channels[numActiveChans], inputChans[i], sizeof (float) * (size_t) numSamples);
                ++numActiveChans;
            }

            for (int i = numInputs; i < numOutputs; ++i)
            {
                channels[numActiveChans] = outputChans[i];
                zeromem (channels[numActiveChans], sizeof (float) * (size_t) numSamples);
                ++numActiveChans;
            }
        }

        AudioSampleBuffer buffer (channels, numActiveChans, numSamples);

        AudioSourceChannelInfo info (&buffer, 0, numSamples);
        source->getNextAudioBlock (info);

        for (int i = info.buffer->getNumChannels(); --i >= 0;)
            buffer.applyGainRamp (i, info.startSample, info.numSamples, lastGain, gain);

        lastGain = gain;
    }
    else
    {
        for (int i = 0; i < totalNumOutputChannels; ++i)
            if (outputChannelData[i] != nullptr)
                zeromem (outputChannelData[i], sizeof (float) * (size_t) numSamples);
    }
}

void AudioSourcePlayer::audioDeviceAboutToStart (AudioIODevice* device)
{
    prepareToPlay (device->getCurrentSampleRate(),
                   device->getCurrentBufferSizeSamples());
}

void AudioSourcePlayer::prepareToPlay (double newSampleRate, int newBufferSize)
{
    sampleRate = newSampleRate;
    bufferSize = newBufferSize;
    zeromem (channels, sizeof (channels));

    if (source != nullptr)
        source->prepareToPlay (bufferSize, sampleRate);
}

void AudioSourcePlayer::audioDeviceStopped()
{
    if (source != nullptr)
        source->releaseResources();

    sampleRate = 0.0;
    bufferSize = 0;

    tempBuffer.setSize (2, 8);
}