1 files changed, 111 insertions, 0 deletions
diff --git a/base/atomic.h b/base/atomic.h
new file mode 100644
index 0000000..becbcc3
--- /dev/null
+++ b/base/atomic.h
@@ -0,0 +1,111 @@
+// Copyright 2008, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//    * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//    * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//    * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef BASE_ATOMIC_H__
+#define BASE_ATOMIC_H__
+
+#if defined(WIN32)
+#include <windows.h>
+#elif defined(__APPLE__)
+#include <libkern/OSAtomic.h>
+#else
+#error Implement atomic support on your platform
+#endif
+
+#include "base/basictypes.h"
+
+namespace base {
+
+///////////////////////////////////////////////////////////////////////////
+//
+// Forward declarations and descriptions of the functions
+//
+///////////////////////////////////////////////////////////////////////////
+
+// Atomically increments *value and returns the resulting incremented value.
+// This function implies no memory barriers.
+int32 AtomicIncrement(volatile int32* value);
+
+// Atomically decrements *value and returns the resulting decremented value.
+// This function implies no memory barriers.
+int32 AtomicDecrement(volatile int32* value);
+
+// Atomically sets *target to new_value and returns the old value of *target.
+// This function implies no memory barriers.
+int32 AtomicSwap(volatile int32* target, int32 new_value);
+
+///////////////////////////////////////////////////////////////////////////
+//
+// Implementations for various platforms
+//
+///////////////////////////////////////////////////////////////////////////
+
+#if defined(WIN32)
+
+inline int32 AtomicIncrement(volatile int32* value) {
+  return InterlockedIncrement(reinterpret_cast<volatile LONG*>(value));
+}
+
+inline int32 AtomicDecrement(volatile int32* value) {
+  return InterlockedDecrement(reinterpret_cast<volatile LONG*>(value));
+}
+
+inline int32 AtomicSwap(volatile int32* target, int32 new_value) {
+  return InterlockedExchange(reinterpret_cast<volatile LONG*>(target),
+                             new_value);
+}
+
+#elif defined(__APPLE__)
+
+inline int32 AtomicIncrement(volatile int32* value) {
+  return OSAtomicIncrement32(reinterpret_cast<volatile int32_t*>(value));
+}
+
+inline int32 AtomicDecrement(volatile int32* value) {
+  return OSAtomicDecrement32(reinterpret_cast<volatile int32_t*>(value));
+}
+
+inline int32 AtomicSwap(volatile int32* target, int32 new_value) {
+  int32 old_value;
+  do {
+    old_value = *target;
+  } while (!OSAtomicCompareAndSwap32(old_value, new_value,
+      reinterpret_cast<volatile int32_t*>(target)));
+  return old_value;
+}
+
+#else
+
+#error Implement atomic support on your platform
+
+#endif
+
+}  // namespace base
+
+#endif // BASE_ATOMIC_H__