JUCE/modules/juce_audio_basics/sources/juce_MemoryAudioSource.cpp

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

   This file is part of the JUCE framework.
   Copyright (c) Raw Material Software Limited

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   Or:

   You may also use this code under the terms of the AGPLv3:
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  ==============================================================================
*/

namespace juce
{

MemoryAudioSource::MemoryAudioSource (AudioBuffer<float>& bufferToUse, bool copyMemory, bool shouldLoop)
    : isCurrentlyLooping (shouldLoop)
{
    if (copyMemory)
        buffer.makeCopyOf (bufferToUse);
    else
        buffer.setDataToReferTo (bufferToUse.getArrayOfWritePointers(),
                                 bufferToUse.getNumChannels(),
                                 bufferToUse.getNumSamples());
}

//==============================================================================
void MemoryAudioSource::prepareToPlay (int /*samplesPerBlockExpected*/, double /*sampleRate*/)
{
    position = 0;
}

void MemoryAudioSource::releaseResources()   {}

void MemoryAudioSource::getNextAudioBlock (const AudioSourceChannelInfo& bufferToFill)
{
    if (buffer.getNumSamples() == 0)
    {
        bufferToFill.clearActiveBufferRegion();
        return;
    }

    auto& dst = *bufferToFill.buffer;
    auto channels = jmin (dst.getNumChannels(), buffer.getNumChannels());
    int max = 0, pos = 0;
    auto n = buffer.getNumSamples();
    auto m = bufferToFill.numSamples;

    int i = position;
    for (; (i < n || isCurrentlyLooping) && (pos < m); i += max)
    {
        max = jmin (m - pos, n - (i % n));

        int ch = 0;
        for (; ch < channels; ++ch)
            dst.copyFrom (ch, bufferToFill.startSample + pos, buffer, ch, i % n, max);

        for (; ch < dst.getNumChannels(); ++ch)
            dst.clear (ch, bufferToFill.startSample + pos, max);

        pos += max;
    }

    if (pos < m)
        dst.clear (bufferToFill.startSample + pos, m - pos);

    position = i;
}

//==============================================================================
void MemoryAudioSource::setNextReadPosition (int64 newPosition)
{
    position = (int) newPosition;
}

int64 MemoryAudioSource::getNextReadPosition() const
{
    return position;
}

int64 MemoryAudioSource::getTotalLength() const
{
    return buffer.getNumSamples();
}

//==============================================================================
bool MemoryAudioSource::isLooping() const
{
    return isCurrentlyLooping;
}

void MemoryAudioSource::setLooping (bool shouldLoop)
{
    isCurrentlyLooping = shouldLoop;
}

//==============================================================================
//==============================================================================
#if JUCE_UNIT_TESTS

struct MemoryAudioSourceTests final : public UnitTest
{
    MemoryAudioSourceTests()  : UnitTest ("MemoryAudioSource", UnitTestCategories::audio)  {}

    void runTest() override
    {
        constexpr int blockSize = 512;
        AudioBuffer<float> bufferToFill { 2, blockSize };
        AudioSourceChannelInfo channelInfo { bufferToFill };

        beginTest ("A zero-length buffer produces silence, whether or not looping is enabled");
        {
            for (const bool enableLooping : { false, true })
            {
                AudioBuffer<float> buffer;
                MemoryAudioSource source { buffer, true, false };
                source.setLooping (enableLooping);
                source.prepareToPlay (blockSize, 44100.0);

                for (int i = 0; i < 2; ++i)
                {
                    play (source, channelInfo);
                    expect (isSilent (bufferToFill));
                }
            }
        }

        beginTest ("A short buffer without looping is played once and followed by silence");
        {
            auto buffer = getShortBuffer();
            MemoryAudioSource source { buffer, true, false };
            source.setLooping (false);
            source.prepareToPlay (blockSize, 44100.0);

            play (source, channelInfo);

            auto copy = buffer;
            copy.setSize (buffer.getNumChannels(), blockSize, true, true, false);

            expect (bufferToFill == copy);

            play (source, channelInfo);

            expect (isSilent (bufferToFill));
        }

        beginTest ("A short buffer with looping is played multiple times");
        {
            auto buffer = getShortBuffer();
            MemoryAudioSource source { buffer, true, false };
            source.setLooping (true);
            source.prepareToPlay (blockSize, 44100.0);

            play (source, channelInfo);

            for (int sample = 0; sample < buffer.getNumSamples(); ++sample)
                expectEquals (bufferToFill.getSample (0, sample + buffer.getNumSamples()), buffer.getSample (0, sample));

            expect (! isSilent (bufferToFill));
        }

        beginTest ("A long buffer without looping is played once");
        {
            auto buffer = getLongBuffer();
            MemoryAudioSource source { buffer, true, false };
            source.setLooping (false);
            source.prepareToPlay (blockSize, 44100.0);

            play (source, channelInfo);

            auto copy = buffer;
            copy.setSize (buffer.getNumChannels(), blockSize, true, true, false);

            expect (bufferToFill == copy);

            for (int i = 0; i < 10; ++i)
                play (source, channelInfo);

            expect (isSilent (bufferToFill));
        }

        beginTest ("A long buffer with looping is played multiple times");
        {
            auto buffer = getLongBuffer();
            MemoryAudioSource source { buffer, true, false };
            source.setLooping (true);
            source.prepareToPlay (blockSize, 44100.0);

            for (int i = 0; i < 100; ++i)
            {
                play (source, channelInfo);
                expectEquals (bufferToFill.getSample (0, 0), buffer.getSample (0, (i * blockSize) % buffer.getNumSamples()));
            }
        }
    }

    static AudioBuffer<float> getTestBuffer (int length)
    {
        AudioBuffer<float> buffer { 2, length };

        for (int channel = 0; channel < buffer.getNumChannels(); ++channel)
            for (int sample = 0; sample < buffer.getNumSamples(); ++sample)
                buffer.setSample (channel, sample, jmap ((float) sample, 0.0f, (float) length, -1.0f, 1.0f));

        return buffer;
    }

    static AudioBuffer<float> getShortBuffer()  { return getTestBuffer (5); }
    static AudioBuffer<float> getLongBuffer()   { return getTestBuffer (1000); }

    static void play (MemoryAudioSource& source, AudioSourceChannelInfo& info)
    {
        info.clearActiveBufferRegion();
        source.getNextAudioBlock (info);
    }

    static bool isSilent (const AudioBuffer<float>& b)
    {
        for (int channel = 0; channel < b.getNumChannels(); ++channel)
            if (b.findMinMax (channel, 0, b.getNumSamples()) != Range<float>{})
                return false;

        return true;
    }
};

static MemoryAudioSourceTests memoryAudioSourceTests;

#endif

} // namespace juce