libopenshot/src/AudioBufferSource.cpp

/**
 * @file
 * @brief Source file for AudioBufferSource class
 * @author Jonathan Thomas <jonathan@openshot.org>
 *
 * @ref License
 */

/* LICENSE
 *
 * Copyright (c) 2008-2019 OpenShot Studios, LLC
 * <http://www.openshotstudios.com/>. This file is part of
 * OpenShot Library (libopenshot), an open-source project dedicated to
 * delivering high quality video editing and animation solutions to the
 * world. For more information visit <http://www.openshot.org/>.
 *
 * OpenShot Library (libopenshot) is free software: you can redistribute it
 * and/or modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * OpenShot Library (libopenshot) is distributed in the hope that it will be
 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with OpenShot Library. If not, see <http://www.gnu.org/licenses/>.
 */

#include "../include/AudioBufferSource.h"

using namespace std;
using namespace openshot;

// Default constructor
AudioBufferSource::AudioBufferSource(AudioSampleBuffer *audio_buffer)
		: position(0), start(0), repeat(false), buffer(audio_buffer)
{ }

// Destructor
AudioBufferSource::~AudioBufferSource()
{
	// forget the AudioSampleBuffer. It still exists; we just don't know about it.
	buffer = NULL;
};

// Get the next block of audio samples
void AudioBufferSource::getNextAudioBlock (const 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 (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
int64 AudioBufferSource::getNextReadPosition() const
{
	// return the next read position
	return position;
}

// Get the total length (in samples) of this audio source
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 AudioSampleBuffer for this source
void AudioBufferSource::setBuffer (AudioSampleBuffer *audio_buffer)
{
	buffer = audio_buffer;
	setNextReadPosition(0);
}