AudioBufferSource.cpp

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// Copyright (c) 2008-2019 OpenShot Studios, LLC
//
// SPDX-License-Identifier: LGPL-3.0-or-later
 
#include "AudioBufferSource.h"
 
using namespace std;
using namespace openshot;
 
// Default constructor
AudioBufferSource::AudioBufferSource(juce::AudioBuffer<float> *audio_buffer)
        : position(0), repeat(false), buffer(audio_buffer)
{ }
 
// Destructor
AudioBufferSource::~AudioBufferSource()
{
    // forget the AudioBuffer<float>. It still exists; we just don't know about it.
    buffer = NULL;
}
 
// Get the next block of audio samples
void AudioBufferSource::getNextAudioBlock (const juce::AudioSourceChannelInfo& info)
{
    int buffer_samples = buffer->getNumSamples();
    int buffer_channels = buffer->getNumChannels();
 
    if (info.numSamples > 0) {
        int start = position;
        int number_to_copy = 0;
 
        // Determine how many samples to copy
        if (start + info.numSamples <= buffer_samples)
        {
            // copy the full amount requested
            number_to_copy = info.numSamples;
        }
        else if (start > buffer_samples)
        {
            // copy nothing
            number_to_copy = 0;
        }
        else if (buffer_samples - start > 0)
        {
            // only copy what is left in the buffer
            number_to_copy = buffer_samples - start;
        }
        else
        {
            // copy nothing
            number_to_copy = 0;
        }
 
        // Determine if any samples need to be copied
        if (number_to_copy > 0)
        {
            // Loop through each channel and copy some samples
            for (int channel = 0; channel < buffer_channels; channel++)
                info.buffer->copyFrom(channel, info.startSample, *buffer, channel, start, number_to_copy);
 
            // Update the position of this audio source
            position += number_to_copy;
        }
 
    }
}
 
// Prepare to play this audio source
void AudioBufferSource::prepareToPlay(int, double) { }
 
// Release all resources
void AudioBufferSource::releaseResources() { }
 
// Set the next read position of this source
void AudioBufferSource::setNextReadPosition (juce::int64 newPosition)
{
    // set position (if the new position is in range)
    if (newPosition >= 0 && newPosition < buffer->getNumSamples())
        position = newPosition;
}
 
// Get the next read position of this source
juce::int64 AudioBufferSource::getNextReadPosition() const
{
    // return the next read position
    return position;
}
 
// Get the total length (in samples) of this audio source
juce::int64 AudioBufferSource::getTotalLength() const
{
    // Get the length
    return buffer->getNumSamples();
}
 
// Determines if this audio source should repeat when it reaches the end
bool AudioBufferSource::isLooping() const
{
    // return if this source is looping
    return repeat;
}
 
// Set if this audio source should repeat when it reaches the end
void AudioBufferSource::setLooping (bool shouldLoop)
{
    // Set the repeat flag
    repeat = shouldLoop;
}
 
// Use a different AudioBuffer<float> for this source
void AudioBufferSource::setBuffer (juce::AudioBuffer<float> *audio_buffer)
{
    buffer = audio_buffer;
    setNextReadPosition(0);
}