ecency-mobile/ios/Pods/Folly/folly/detail/CachelinePaddedImpl.h

58 lines
1.7 KiB
C++

/*
* Copyright 2016 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <folly/detail/CacheLocality.h>
namespace folly {
template <typename T>
class CachelinePadded;
namespace detail {
template <
typename T,
bool needsPadding = (sizeof(T) % CacheLocality::kFalseSharingRange != 0)>
struct CachelinePaddedImpl;
// We need alignas(T) alignas(kFalseSharingRange) for the case where alignof(T)
// > alignof(kFalseSharingRange).
template <typename T>
struct alignas(T) alignas(detail::CacheLocality::kFalseSharingRange)
CachelinePaddedImpl<T, /* needsPadding = */ false> {
template <typename... Args>
explicit CachelinePaddedImpl(Args&&... args)
: item(std::forward<Args>(args)...) {}
T item;
};
template <typename T>
struct alignas(T) alignas(detail::CacheLocality::kFalseSharingRange)
CachelinePaddedImpl<T, /* needsPadding = */ true> {
template <typename... Args>
explicit CachelinePaddedImpl(Args&&... args)
: item(std::forward<Args>(args)...) {}
T item;
char padding
[CacheLocality::kFalseSharingRange -
sizeof(T) % CacheLocality::kFalseSharingRange];
};
} // namespace detail
} // namespace folly