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

media/base/audio_bus.h

 // 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.
 
 #ifndef MEDIA_BASE_AUDIO_BUS_H_
 #define MEDIA_BASE_AUDIO_BUS_H_
 
 #include <vector>
 
 #include "base/memory/aligned_memory.h"
 #include "base/memory/scoped_ptr.h"
 #include "media/base/media_export.h"
 
+#if defined(OS_MACOSX)
+struct AudioBufferList;
+#endif
+
 namespace media {
 class AudioParameters;
 
 // Scoped container for "busing" audio channel data around.  Each channel is
 // stored in planar format and guaranteed to be aligned by kChannelAlignment.
 // AudioBus objects can be created normally or via wrapping.  Normally, AudioBus
 // will dice up a contiguous memory block for channel data.  When wrapped,
 // AudioBus instead routes requests for channel data to the wrapped object.
 class MEDIA_EXPORT AudioBus {
  public:
   // Guaranteed alignment of each channel's data; use 16-byte alignment for easy
   // SSE optimizations.
   enum { kChannelAlignment = 16 };
 
+  AudioBus(int channels, int frames);
+  AudioBus(int channels, int frames, float* data);
+  AudioBus(int frames, const std::vector<float*>& channel_data);
+
+#if defined(OS_MACOSX)
+  AudioBus(int channels, int frames, AudioBufferList* buffer_list);

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

let's try to close out this issue sooner rather than later -- perhaps using a
resize() method as dale suggests

+#endif
+
+  ~AudioBus();
+
   // Creates a new AudioBus and allocates |channels| of length |frames|.  Uses
   // channels() and frames_per_buffer() from AudioParameters if given.
   static scoped_ptr<AudioBus> Create(int channels, int frames);
   static scoped_ptr<AudioBus> Create(const AudioParameters& params);
 
   // Creates a new AudioBus from an existing channel vector.  Does not transfer
   // ownership of |channel_data| to AudioBus; i.e., |channel_data| must outlive
   // the returned AudioBus.  Each channel must be aligned by kChannelAlignment.
   static scoped_ptr<AudioBus> WrapVector(
       int frames, const std::vector<float*>& channel_data);
@@ skipping 40 matching lines @@
   int channels() const { return channel_data_.size(); }
   int frames() const { return frames_; }
 
   // Helper method for zeroing out all channels of audio data.
   void Zero();
   void ZeroFrames(int frames);
   void ZeroFramesPartial(int start_frame, int frames);
 
  private:
   friend class scoped_ptr<AudioBus>;
-  ~AudioBus();
-
-  AudioBus(int channels, int frames);
-  AudioBus(int channels, int frames, float* data);
-  AudioBus(int frames, const std::vector<float*>& channel_data);
 
   // Helper method for building |channel_data_| from a block of memory.  |data|
   // must be at least BlockSize() bytes in size.
   void BuildChannelData(int channels, int aligned_frame, float* data);
 
   // Contiguous block of channel memory.
   scoped_ptr_malloc<float, base::ScopedPtrAlignedFree> data_;
 
   std::vector<float*> channel_data_;
   int frames_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioBus);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_AUDIO_BUS_H_