diff options
Diffstat (limited to 'media')
| -rw-r--r-- | media/audio/audio_util.cc | 40 | ||||
| -rw-r--r-- | media/audio/audio_util.h | 15 |
2 files changed, 55 insertions, 0 deletions
diff --git a/media/audio/audio_util.cc b/media/audio/audio_util.cc index 18e2abb..fe5fb10 100644 --- a/media/audio/audio_util.cc +++ b/media/audio/audio_util.cc @@ -8,13 +8,19 @@ // Implemented as templates to allow 8, 16 and 32 bit implementations. // 8 bit is unsigned and biased by 128. +#include <algorithm> + +#include "base/atomicops.h" #include "base/basictypes.h" #include "base/logging.h" +#include "base/shared_memory.h" #include "media/audio/audio_util.h" #if defined(OS_MACOSX) #include "media/audio/mac/audio_low_latency_output_mac.h" #endif +using base::subtle::Atomic32; + namespace media { // TODO(fbarchard): Convert to intrinsics for better efficiency. @@ -234,4 +240,38 @@ double GetAudioHardwareSampleRate() #endif } +// When transferring data in the shared memory, first word is size of data +// in bytes. Actual data starts immediately after it. + +uint32 TotalSharedMemorySizeInBytes(uint32 packet_size) { + // Need to reserve extra 4 bytes for size of data. + return packet_size + sizeof(Atomic32); +} + +uint32 PacketSizeSizeInBytes(uint32 shared_memory_created_size) { + return shared_memory_created_size - sizeof(Atomic32); +} + +uint32 GetActualDataSizeInBytes(base::SharedMemory* shared_memory, + uint32 shared_memory_size) { + char* ptr = static_cast<char*>(shared_memory->memory()) + shared_memory_size; + DCHECK_EQ(0u, reinterpret_cast<size_t>(ptr) & 3); + + // Actual data size stored in the beginning of the buffer. + uint32 actual_data_size = + base::subtle::Acquire_Load(reinterpret_cast<volatile Atomic32*>(ptr)); + return std::min(actual_data_size, shared_memory_size); +} + +void SetActualDataSizeInBytes(base::SharedMemory* shared_memory, + uint32 shared_memory_size, + uint32 actual_data_size) { + char* ptr = static_cast<char*>(shared_memory->memory()) + shared_memory_size; + DCHECK_EQ(0u, reinterpret_cast<size_t>(ptr) & 3); + + // Set actual data size in the beginning of the buffer. + base::subtle::Release_Store(reinterpret_cast<volatile Atomic32*>(ptr), + actual_data_size); +} + } // namespace media diff --git a/media/audio/audio_util.h b/media/audio/audio_util.h index 0d65e19..a2fa15e 100644 --- a/media/audio/audio_util.h +++ b/media/audio/audio_util.h @@ -9,6 +9,10 @@ #include "base/basictypes.h" +namespace base { +class SharedMemory; +} + namespace media { // For all audio functions 3 audio formats are supported: @@ -77,6 +81,17 @@ void InterleaveFloatToInt16(const std::vector<float*>& source, // Returns the default audio hardware sample-rate. double GetAudioHardwareSampleRate(); +// Functions that handle data buffer passed between processes in the shared +// memory. Called on both IPC sides. + +uint32 TotalSharedMemorySizeInBytes(uint32 packet_size); +uint32 PacketSizeSizeInBytes(uint32 shared_memory_created_size); +uint32 GetActualDataSizeInBytes(base::SharedMemory* shared_memory, + uint32 shared_memory_size); +void SetActualDataSizeInBytes(base::SharedMemory* shared_memory, + uint32 shared_memory_size, + uint32 actual_data_size); + } // namespace media #endif // MEDIA_AUDIO_AUDIO_UTIL_H_ |