#include <cassert>
#include <cstring>
+#include <cmath>
#include <stdexcept>
#include "audio_buffers.h"
void
AudioBuffers::allocate (int channels, int frames)
{
+ assert (frames >= 0);
+ assert (channels >= 0);
+
_channels = channels;
_frames = frames;
_allocated_frames = frames;
}
/** Set the number of frames that these AudioBuffers will report themselves
- * as having.
+ * 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;
}
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);
}
}
-/** Add data from from `from', `from_channel' to our channel `to_channel' */
+/** Add data from from `from', `from_channel' to our channel `to_channel'.
+ * @param gain Linear gain to apply to the data before it is added.
+ */
void
-AudioBuffers::accumulate_channel (AudioBuffers const * from, int from_channel, int to_channel)
+AudioBuffers::accumulate_channel (AudioBuffers const * from, int from_channel, int to_channel, float gain)
{
int const N = frames ();
assert (from->frames() == N);
float* d = _data[to_channel];
for (int i = 0; i < N; ++i) {
- *d++ += *s++;
+ *d++ += (*s++) * gain;
}
}
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) {
}
}
+/** @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;
+ }
+ }
+}