1 files changed, 275 insertions, 0 deletions
diff --git a/src/lib/audio_buffers.cc b/src/lib/audio_buffers.cc
new file mode 100644
index 000000000..e80142b8e
--- /dev/null
+++ b/src/lib/audio_buffers.cc
@@ -0,0 +1,275 @@
+/*
+    Copyright (C) 2012-2013 Carl Hetherington <cth@carlh.net>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program 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 General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#include <cassert>
+#include <cstring>
+#include <cmath>
+#include <stdexcept>
+#include "audio_buffers.h"
+
+using std::bad_alloc;
+using boost::shared_ptr;
+
+/** Construct an AudioBuffers.  Audio data is undefined after this constructor.
+ *  @param channels Number of channels.
+ *  @param frames Number of frames to reserve space for.
+ */
+AudioBuffers::AudioBuffers (int channels, int frames)
+{
+	allocate (channels, frames);
+}
+
+/** Copy constructor.
+ *  @param other Other AudioBuffers; data is copied.
+ */
+AudioBuffers::AudioBuffers (AudioBuffers const & other)
+{
+	allocate (other._channels, other._frames);
+	copy_from (&other, other._frames, 0, 0);
+}
+
+AudioBuffers::AudioBuffers (boost::shared_ptr<const AudioBuffers> other)
+{
+	allocate (other->_channels, other->_frames);
+	copy_from (other.get(), other->_frames, 0, 0);
+}
+
+AudioBuffers &
+AudioBuffers::operator= (AudioBuffers const & other)
+{
+	if (this == &other) {
+		return *this;
+	}
+		
+	deallocate ();
+	allocate (other._channels, other._frames);
+	copy_from (&other, other._frames, 0, 0);
+
+	return *this;
+}
+
+/** AudioBuffers destructor */
+AudioBuffers::~AudioBuffers ()
+{
+	deallocate ();
+}
+
+void
+AudioBuffers::allocate (int channels, int frames)
+{
+	_channels = channels;
+	_frames = frames;
+	_allocated_frames = frames;
+	
+	_data = static_cast<float**> (malloc (_channels * sizeof (float *)));
+	if (!_data) {
+		throw bad_alloc ();
+	}
+	
+	for (int i = 0; i < _channels; ++i) {
+		_data[i] = static_cast<float*> (malloc (frames * sizeof (float)));
+		if (!_data[i]) {
+			throw bad_alloc ();
+		}
+	}
+}
+
+void
+AudioBuffers::deallocate ()
+{
+	for (int i = 0; i < _channels; ++i) {
+		free (_data[i]);
+	}
+
+	free (_data);
+}
+
+/** @param c Channel index.
+ *  @return Buffer for this channel.
+ */
+float*
+AudioBuffers::data (int c) const
+{
+	assert (c >= 0 && c < _channels);
+	return _data[c];
+}
+
+/** Set the number of frames that these AudioBuffers will report themselves
+ *  as having.  If we reduce the number of frames, the `lost' frames will
+ *  be silenced.
+ *  @param f Frames; must be less than or equal to the number of allocated frames.
+ */
+void
+AudioBuffers::set_frames (int f)
+{
+	assert (f <= _allocated_frames);
+
+	for (int c = 0; c < _channels; ++c) {
+		for (int i = f; i < _frames; ++i) {
+			_data[c][i] = 0;
+		}
+	}
+	
+	_frames = f;
+}
+
+/** Make all samples on all channels silent */
+void
+AudioBuffers::make_silent ()
+{
+	for (int i = 0; i < _channels; ++i) {
+		make_silent (i);
+	}
+}
+
+/** Make all samples on a given channel silent.
+ *  @param c Channel.
+ */
+void
+AudioBuffers::make_silent (int c)
+{
+	assert (c >= 0 && c < _channels);
+	
+	for (int i = 0; i < _frames; ++i) {
+		_data[c][i] = 0;
+	}
+}
+
+void
+AudioBuffers::make_silent (int from, int frames)
+{
+	assert ((from + frames) <= _allocated_frames);
+
+	for (int c = 0; c < _channels; ++c) {
+		for (int i = from; i < (from + frames); ++i) {
+			_data[c][i] = 0;
+		}
+	}
+}
+
+/** Copy data from another AudioBuffers to this one.  All channels are copied.
+ *  @param from AudioBuffers to copy from; must have the same number of channels as this.
+ *  @param frames_to_copy Number of frames to copy.
+ *  @param read_offset Offset to read from in `from'.
+ *  @param write_offset Offset to write to in `to'.
+ */
+void
+AudioBuffers::copy_from (AudioBuffers const * from, int frames_to_copy, int read_offset, int write_offset)
+{
+	assert (from->channels() == channels());
+
+	assert (from);
+	assert (read_offset >= 0 && (read_offset + frames_to_copy) <= from->_allocated_frames);
+	assert (write_offset >= 0 && (write_offset + frames_to_copy) <= _allocated_frames);
+
+	for (int i = 0; i < _channels; ++i) {
+		memcpy (_data[i] + write_offset, from->_data[i] + read_offset, frames_to_copy * sizeof(float));
+	}
+}
+
+/** Move audio data around.
+ *  @param from Offset to move from.
+ *  @param to Offset to move to.
+ *  @param frames Number of frames to move.
+ */
+    
+void
+AudioBuffers::move (int from, int to, int frames)
+{
+	if (frames == 0) {
+		return;
+	}
+	
+	assert (from >= 0);
+	assert (from < _frames);
+	assert (to >= 0);
+	assert (to < _frames);
+	assert (frames > 0);
+	assert (frames <= _frames);
+	assert ((from + frames) <= _frames);
+	assert ((to + frames) <= _allocated_frames);
+	
+	for (int i = 0; i < _channels; ++i) {
+		memmove (_data[i] + to, _data[i] + from, frames * sizeof(float));
+	}
+}
+
+/** Add data from from `from', `from_channel' to our channel `to_channel' */
+void
+AudioBuffers::accumulate_channel (AudioBuffers const * from, int from_channel, int to_channel)
+{
+	int const N = frames ();
+	assert (from->frames() == N);
+	assert (to_channel <= _channels);
+
+	float* s = from->data (from_channel);
+	float* d = _data[to_channel];
+
+	for (int i = 0; i < N; ++i) {
+		*d++ += *s++;
+	}
+}
+
+/** Ensure we have space for at least a certain number of frames.  If we extend
+ *  the buffers, fill the new space with silence.
+ */
+void
+AudioBuffers::ensure_size (int frames)
+{
+	if (_allocated_frames >= frames) {
+		return;
+	}
+
+	for (int i = 0; i < _channels; ++i) {
+		_data[i] = static_cast<float*> (realloc (_data[i], frames * sizeof (float)));
+		if (!_data[i]) {
+			throw bad_alloc ();
+		}
+		for (int j = _allocated_frames; j < frames; ++j) {
+			_data[i][j] = 0;
+		}
+	}
+
+	_allocated_frames = frames;
+}
+
+void
+AudioBuffers::accumulate_frames (AudioBuffers const * from, int read_offset, int write_offset, int frames)
+{
+	assert (_channels == from->channels ());
+
+	for (int i = 0; i < _channels; ++i) {
+		for (int j = 0; j < frames; ++j) {
+			_data[i][j + write_offset] += from->data()[i][j + read_offset];
+		}
+	}
+}
+
+/** @param dB gain in dB */
+void
+AudioBuffers::apply_gain (float dB)
+{
+	float const linear = pow (10, dB / 20);
+	
+	for (int i = 0; i < _channels; ++i) {
+		for (int j = 0; j < _frames; ++j) {
+			_data[i][j] *= linear;
+		}
+	}
+}