Use memset for zeroing float buffers; it's faster, and I think

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

diff --git a/src/lib/audio_buffers.cc b/src/lib/audio_buffers.cc
index 825c6c2f3219fa8bd6347d7aeddfc97fc005a29b..8d3a897c42d76eb7ecd7f0474afdba63ba014a27 100644 (file)
--- a/src/lib/audio_buffers.cc
+++ b/src/lib/audio_buffers.cc
@@ -125,12 +125,7 @@ AudioBuffers::set_frames (int32_t f)
 {
        DCPOMATIC_ASSERT (f <= _allocated_frames);
 
-       for (int c = 0; c < _channels; ++c) {
-               for (int i = f; i < _frames; ++i) {
-                       _data[c][i] = 0;
-               }
-       }
-
+       make_silent (f, _frames - f);
        _frames = f;
 }
 
@@ -151,9 +146,10 @@ AudioBuffers::make_silent (int c)
 {
        DCPOMATIC_ASSERT (c >= 0 && c < _channels);
 
-       for (int i = 0; i < _frames; ++i) {
-               _data[c][i] = 0;
-       }
+       /* This isn't really allowed, as all-bits-0 is not guaranteed to mean a 0 float,
+          but it seems that we can get away with it.
+       */
+       memset (_data[c], 0, _frames * sizeof(float));
 }
 
 /** Make some frames.
@@ -166,9 +162,10 @@ AudioBuffers::make_silent (int32_t from, int32_t frames)
        DCPOMATIC_ASSERT ((from + frames) <= _allocated_frames);
 
        for (int c = 0; c < _channels; ++c) {
-               for (int i = from; i < (from + frames); ++i) {
-                       _data[c][i] = 0;
-               }
+               /* This isn't really allowed, as all-bits-0 is not guaranteed to mean a 0 float,
+                  but it seems that we can get away with it.
+               */
+               memset (_data[c] + from, 0, frames * sizeof(float));
        }
 }
 
@@ -270,11 +267,9 @@ AudioBuffers::ensure_size (int32_t frames)
                if (!_data[i]) {
                        throw bad_alloc ();
                }
-               for (int j = _allocated_frames; j < frames; ++j) {
-                       _data[i][j] = 0;
-               }
        }
 
+       make_silent (_allocated_frames, frames - _allocated_frames);
        _allocated_frames = frames;
 }