AudioBus: Add a ToInterleavedFloat() method to AudioBus

media/base/audio_bus.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/base/audio_bus.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <limits>
@@ skipping 282 matching lines @@
 void AudioBus::FromInterleaved(const void* source, int frames,
                                int bytes_per_sample) {
   FromInterleavedPartial(source, 0, frames, bytes_per_sample);
 }
 
 void AudioBus::ToInterleaved(int frames, int bytes_per_sample,
                              void* dest) const {
   ToInterleavedPartial(0, frames, bytes_per_sample, dest);
 }
 
+// Interleaves |audio_bus| channels() of floats into a single output linear
+// |buffer|.
+void AudioBus::ToInterleavedFloat(int source_offset,
+                                  int destination_offset,
+                                  int num_samples,
+                                  float* buffer) const {
+  CheckOverflow(source_offset, destination_offset, num_samples);
+  for (int ch = 0; ch < channels(); ++ch) {
+    const float* src = channel(ch) + source_offset;
+    const float* const src_end = src + num_samples;
+    float* dest = buffer + destination_offset + ch;
+    for (; src < src_end; ++src, dest += channels())

[mcasas, 2016/06/02 01:13:14]

nit: every cycle counts, so get channels() evaluation out
of both loops:
 const int channels = channels();

[chfremer, 2016/06/02 18:13:33]

As per the discussion in the corresponding bug entry [1], I am not sure whether
or not we will keep this newly added code. Will address this if we decide to
keep it.

[1] https://bugs.chromium.org/p/chromium/issues/detail?id=580391

+      *dest = *src;
+  }
+}
+
 // TODO(dalecurtis): See if intrinsic optimizations help any here.
 void AudioBus::ToInterleavedPartial(int start_frame, int frames,
                                     int bytes_per_sample, void* dest) const {
   CheckOverflow(start_frame, frames, frames_);
   switch (bytes_per_sample) {
     case 1:
       ToInterleavedInternal<uint8_t, int16_t, kUint8Bias>(
           this, start_frame, frames, dest, std::numeric_limits<int8_t>::min(),
           std::numeric_limits<int8_t>::max());
       break;
@@ skipping 56 matching lines @@
   return scoped_refptr<AudioBusRefCounted>(
       new AudioBusRefCounted(channels, frames));
 }
 
 AudioBusRefCounted::AudioBusRefCounted(int channels, int frames)
     : AudioBus(channels, frames) {}
 
 AudioBusRefCounted::~AudioBusRefCounted() {}
 
 }  // namespace media