95 lines
2.9 KiB
C++
95 lines
2.9 KiB
C++
/*
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* Copyright 2011 The WebRTC Project Authors. All rights reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef RTC_BASE_ATOMICOPS_H_
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#define RTC_BASE_ATOMICOPS_H_
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#if defined(WEBRTC_WIN)
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// clang-format off
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// clang formating would change include order.
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// Include winsock2.h before including <windows.h> to maintain consistency with
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// win32.h. To include win32.h directly, it must be broken out into its own
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// build target.
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#include <winsock2.h>
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#include <windows.h>
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// clang-format on
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#endif // defined(WEBRTC_WIN)
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namespace rtc
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{
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class AtomicOps
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{
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public:
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#if defined(WEBRTC_WIN)
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// Assumes sizeof(int) == sizeof(LONG), which it is on Win32 and Win64.
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static int Increment(volatile int* i)
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{
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return ::InterlockedIncrement(reinterpret_cast<volatile LONG*>(i));
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}
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static int Decrement(volatile int* i)
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{
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return ::InterlockedDecrement(reinterpret_cast<volatile LONG*>(i));
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}
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static int AcquireLoad(volatile const int* i) { return *i; }
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static void ReleaseStore(volatile int* i, int value) { *i = value; }
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static int CompareAndSwap(volatile int* i, int old_value, int new_value)
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{
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return ::InterlockedCompareExchange(reinterpret_cast<volatile LONG*>(i),
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new_value, old_value);
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}
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// Pointer variants.
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template <typename T>
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static T* AcquireLoadPtr(T* volatile* ptr)
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{
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return *ptr;
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}
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template <typename T>
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static T* CompareAndSwapPtr(T* volatile* ptr, T* old_value, T* new_value)
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{
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return static_cast<T*>(::InterlockedCompareExchangePointer(
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reinterpret_cast<PVOID volatile*>(ptr), new_value, old_value));
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}
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#else
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static int Increment(volatile int* i)
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{
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return __sync_add_and_fetch(i, 1);
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}
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static int Decrement(volatile int* i) { return __sync_sub_and_fetch(i, 1); }
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static int AcquireLoad(volatile const int* i)
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{
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return __atomic_load_n(i, __ATOMIC_ACQUIRE);
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}
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static void ReleaseStore(volatile int* i, int value)
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{
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__atomic_store_n(i, value, __ATOMIC_RELEASE);
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}
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static int CompareAndSwap(volatile int* i, int old_value, int new_value)
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{
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return __sync_val_compare_and_swap(i, old_value, new_value);
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}
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// Pointer variants.
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template <typename T>
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static T* AcquireLoadPtr(T* volatile* ptr)
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{
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return __atomic_load_n(ptr, __ATOMIC_ACQUIRE);
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}
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template <typename T>
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static T* CompareAndSwapPtr(T* volatile* ptr, T* old_value, T* new_value)
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{
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return __sync_val_compare_and_swap(ptr, old_value, new_value);
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}
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#endif
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};
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} // namespace rtc
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#endif // RTC_BASE_ATOMICOPS_H_
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