+/*
+ Copyright (C) 2013-2016 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 "audio_merger.h"
+#include "dcpomatic_time.h"
+
+using std::pair;
+using std::min;
+using std::max;
+using std::make_pair;
+using boost::shared_ptr;
+
+AudioMerger::AudioMerger (int channels, int frame_rate)
+ : _buffers (new AudioBuffers (channels, 0))
+ , _last_pull (0)
+ , _frame_rate (frame_rate)
+{
+
+}
+
+/** Pull audio up to a given time; after this call, no more data can be pushed
+ * before the specified time.
+ */
+pair<shared_ptr<AudioBuffers>, DCPTime>
+AudioMerger::pull (DCPTime time)
+{
+ /* Number of frames to return */
+ Frame const to_return = time.frames_floor (_frame_rate) - _last_pull.frames_floor (_frame_rate);
+ shared_ptr<AudioBuffers> out (new AudioBuffers (_buffers->channels(), to_return));
+
+ /* And this is how many we will get from our buffer */
+ Frame const to_return_from_buffers = min (to_return, Frame (_buffers->frames()));
+
+ /* Copy the data that we have to the back end of the return buffer */
+ out->copy_from (_buffers.get(), to_return_from_buffers, 0, to_return - to_return_from_buffers);
+ /* Silence any gap at the start */
+ out->make_silent (0, to_return - to_return_from_buffers);
+
+ DCPTime out_time = _last_pull;
+ _last_pull = time;
+
+ /* And remove the data we're returning from our buffers */
+ if (_buffers->frames() > to_return_from_buffers) {
+ _buffers->move (to_return_from_buffers, 0, _buffers->frames() - to_return_from_buffers);
+ }
+ _buffers->set_frames (_buffers->frames() - to_return_from_buffers);
+
+ return make_pair (out, out_time);
+}
+
+void
+AudioMerger::push (boost::shared_ptr<const AudioBuffers> audio, DCPTime time)
+{
+ DCPOMATIC_ASSERT (time >= _last_pull);
+
+ Frame const frame = time.frames_floor (_frame_rate);
+ Frame after = max (Frame (_buffers->frames()), frame + audio->frames() - _last_pull.frames_floor (_frame_rate));
+ _buffers->ensure_size (after);
+ _buffers->accumulate_frames (audio.get(), 0, frame - _last_pull.frames_floor (_frame_rate), audio->frames ());
+ _buffers->set_frames (after);
+}