media/audio/shared_memory_util.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef MEDIA_AUDIO_SHARED_MEMORY_UTIL_H_
   6 #define MEDIA_AUDIO_SHARED_MEMORY_UTIL_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/memory/shared_memory.h"
  10 #include "media/base/media_export.h"
  11
  12 namespace media {
  13
  14 // Value sent by the controller to the renderer in low-latency mode
  15 // indicating that the stream is paused.
  16 enum { kPauseMark = -1 };
  17
  18 // Functions that handle data buffer passed between processes in the shared
  19 // memory.  Called on both IPC sides.  These are necessary because the shared
  20 // memory has a layout: the last word in the block is the data size in bytes.
  21
  22 MEDIA_EXPORT uint32 TotalSharedMemorySizeInBytes(uint32 packet_size);
  23 MEDIA_EXPORT uint32 PacketSizeInBytes(uint32 shared_memory_created_size);
  24 MEDIA_EXPORT uint32 GetActualDataSizeInBytes(base::SharedMemory* shared_memory,
  25                                              uint32 packet_size);
  26 MEDIA_EXPORT void SetActualDataSizeInBytes(base::SharedMemory* shared_memory,
  27                                            uint32 packet_size,
  28                                            uint32 actual_data_size);
  29 MEDIA_EXPORT void SetActualDataSizeInBytes(void* shared_memory_ptr,
  30                                            uint32 packet_size,
  31                                            uint32 actual_data_size);
  32 MEDIA_EXPORT void SetUnknownDataSize(base::SharedMemory* shared_memory,
  33                                      uint32 packet_size);
  34 MEDIA_EXPORT bool IsUnknownDataSize(base::SharedMemory* shared_memory,
  35                                     uint32 packet_size);
  36
  37 }  // namespace media
  38
  39 #endif  // MEDIA_AUDIO_SHARED_MEMORY_UTIL_H_