Revert 152406 - Introduce shared_memory_support media target for PPAPI.

media/audio/audio_util.cc

Index: media/audio/audio_util.cc
===================================================================
--- media/audio/audio_util.cc	(revision 152430)
+++ media/audio/audio_util.cc	(working copy)
@@ -12,15 +12,16 @@
 // that a lot of the functions can be simplified and made more elegant. Revisit
 // after other audio cleanup is done. (crbug.com/120319)
 
-#include "media/audio/audio_util.h"
-
 #include <algorithm>
 #include <limits>
 
+#include "base/atomicops.h"
 #include "base/basictypes.h"
 #include "base/logging.h"
+#include "base/shared_memory.h"
 #include "base/time.h"
 #include "media/audio/audio_parameters.h"
+#include "media/audio/audio_util.h"
 #include "media/base/audio_bus.h"
 
 #if defined(OS_MACOSX)
@@ -35,6 +36,10 @@
 #include "media/base/media_switches.h"
 #endif
 
+using base::subtle::Atomic32;
+
+const uint32 kUnknownDataSize = static_cast<uint32>(-1);
+
 namespace media {
 
 // TODO(fbarchard): Convert to intrinsics for better efficiency.
@@ -478,6 +483,56 @@
   return samples;
 }
 
+// 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 at the end 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 at the end of the buffer.
+  base::subtle::Release_Store(reinterpret_cast<volatile Atomic32*>(ptr),
+                              actual_data_size);
+}
+
+void SetUnknownDataSize(base::SharedMemory* shared_memory,
+                        uint32 shared_memory_size) {
+  SetActualDataSizeInBytes(shared_memory, shared_memory_size, kUnknownDataSize);
+}
+
+bool IsUnknownDataSize(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 at the end of the buffer.
+  uint32 actual_data_size =
+      base::subtle::Acquire_Load(reinterpret_cast<volatile Atomic32*>(ptr));
+  return actual_data_size == kUnknownDataSize;
+}
+
 #if defined(OS_WIN)
 
 bool IsWASAPISupported() {
Property changes on: media/audio/audio_util.cc
___________________________________________________________________
Added: svn:mergeinfo