Merge master.

[dcpomatic.git] / src / lib / audio_buffers.cc

diff --git a/src/lib/audio_buffers.cc b/src/lib/audio_buffers.cc
index 8d00fa8ba5a2bec7d0d5894cc1ea730d4beedb21..56ca7a94b18c5860e3800f03740baa2c09480d59 100644 (file)
--- a/src/lib/audio_buffers.cc
+++ b/src/lib/audio_buffers.cc
@@ -175,6 +175,11 @@ AudioBuffers::make_silent (int from, int frames)
 void
 AudioBuffers::copy_from (AudioBuffers const * from, int frames_to_copy, int read_offset, int write_offset)
 {
+       if (frames_to_copy == 0) {
+               /* Prevent the asserts from firing if there is nothing to do */
+               return;
+       }
+       
        assert (from->channels() == channels());
 
        assert (from);
@@ -258,6 +263,8 @@ void
 AudioBuffers::accumulate_frames (AudioBuffers const * from, int read_offset, int write_offset, int frames)
 {
        assert (_channels == from->channels ());
+       assert (read_offset >= 0);
+       assert (write_offset >= 0);
 
        for (int i = 0; i < _channels; ++i) {
                for (int j = 0; j < frames; ++j) {
@@ -278,3 +285,29 @@ AudioBuffers::apply_gain (float dB)
                }
        }
 }
+
+/** @param c Channel index.
+ *  @return AudioBuffers object containing only channel `c' from this AudioBuffers.
+ */
+shared_ptr<AudioBuffers>
+AudioBuffers::channel (int c) const
+{
+       shared_ptr<AudioBuffers> o (new AudioBuffers (1, frames ()));
+       o->copy_channel_from (this, c, 0);
+       return o;
+}
+
+void
+AudioBuffers::copy_channel_from (AudioBuffers const * from, int from_channel, int to_channel)
+{
+       assert (from->frames() == frames());
+       memcpy (data(to_channel), from->data(from_channel), frames() * sizeof (float));
+}
+
+shared_ptr<AudioBuffers>
+AudioBuffers::clone () const
+{
+       shared_ptr<AudioBuffers> b (new AudioBuffers (channels (), frames ()));
+       b->copy_from (this, frames (), 0, 0);
+       return b;
+}