Add Mac OS X synchronized audio I/O back-end

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 <limits>
 
 #include "base/logging.h"
 #include "media/audio/audio_parameters.h"
 #include "media/base/limits.h"
 
+#if defined(OS_MACOSX)

[no longer working on chromium, 2012/09/17 20:47:46]

move this above #include <limits>

+#include <CoreAudio/CoreAudioTypes.h>
+#endif
+
 namespace media {
 
 static bool IsAligned(void* ptr) {
   return (reinterpret_cast<uintptr_t>(ptr) &
           (AudioBus::kChannelAlignment - 1)) == 0U;
 }
 
 // Calculates the required size for an AudioBus with the given params, sets
 // |aligned_frames| to the actual frame length of each channel array.
 static int CalculateMemorySizeInternal(int channels, int frames,
@@ skipping 107 matching lines @@
 AudioBus::AudioBus(int frames, const std::vector<float*>& channel_data)
     : channel_data_(channel_data),
       frames_(frames) {
   ValidateConfig(channel_data_.size(), frames_);
 
   // Sanity check wrapped vector for alignment and channel count.
   for (size_t i = 0; i < channel_data_.size(); ++i)
     DCHECK(IsAligned(channel_data_[i]));
 }
 
+#if defined(OS_MACOSX)
+AudioBus::AudioBus(int channels, int frames, AudioBufferList* buffer_list)
+    : frames_(frames) {
+  ValidateConfig(channels, frames_);
+
+  channel_data_.reserve(channels);
+
+  // Copy pointers from AudioBufferList.
+  // It's ok to pass in a |buffer_list| with fewer channels, in which
+  // case we just duplicate the last channel.
+  int source_idx = 0;
+  for (int i = 0; i < channels; ++i) {

[no longer working on chromium, 2012/09/17 20:47:46]

we should be able to use only either source_idx or i

+    channel_data_.push_back(
+        static_cast<float*>(buffer_list->mBuffers[source_idx].mData));

[scherkus (not reviewing), 2012/09/17 14:51:17]

it does seem that we could have this bit of code as a helper method for mac w/o
introducing OS-specific bits into an OS-independent class

+    DCHECK(IsAligned(channel_data_[i]));
+
+    if (source_idx < channels - 1)
+      ++source_idx;
+  }
+}
+#endif
+
 AudioBus::~AudioBus() {}
 
 scoped_ptr<AudioBus> AudioBus::Create(int channels, int frames) {
   return scoped_ptr<AudioBus>(new AudioBus(channels, frames));
 }
 
 scoped_ptr<AudioBus> AudioBus::Create(const AudioParameters& params) {
   return scoped_ptr<AudioBus>(new AudioBus(
       params.channels(), params.frames_per_buffer()));
 }
@@ skipping 115 matching lines @@
   DCHECK_EQ(channels(), dest->channels());
   DCHECK_EQ(frames(), dest->frames());
 
   // Since we don't know if the other AudioBus is wrapped or not (and we don't
   // want to care), just copy using the public channel() accessors.
   for (int i = 0; i < channels(); ++i)
     memcpy(dest->channel(i), channel(i), sizeof(*channel(i)) * frames());
 }
 
 }  // namespace media