105 lines
2.9 KiB
C
105 lines
2.9 KiB
C
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/*
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* Copyright (c) Facebook, Inc. and its affiliates.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#pragma once
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#include <cstddef>
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#include <type_traits>
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#include <utility>
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#include <folly/Utility.h>
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#include <folly/lang/Align.h>
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namespace folly {
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template <typename T, std::size_t Align>
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class aligned {
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static_assert(!(Align & (Align - 1)), "alignment not a power of two");
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static_assert(alignof(T) <= Align, "alignment too small");
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public:
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using alignment = index_constant<Align>;
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using value_type = T;
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aligned() = default;
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aligned(aligned const&) = default;
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aligned(aligned&&) = default;
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template <
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typename S = T,
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std::enable_if_t<std::is_copy_constructible<S>::value, int> = 0>
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aligned(T const& value) noexcept(std::is_nothrow_copy_constructible<T>::value)
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: value_(value) {}
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template <
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typename S = T,
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std::enable_if_t<std::is_move_constructible<S>::value, int> = 0>
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aligned(T&& value) noexcept(std::is_nothrow_move_constructible<T>::value)
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: value_(static_cast<T&&>(value)) {}
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template <
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typename... A,
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std::enable_if_t<std::is_constructible<T, A...>::value, int> = 0>
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explicit aligned(in_place_t, A&&... a) noexcept(
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std::is_nothrow_constructible<T, A...>::value)
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: value_(static_cast<A&&>(a)...) {}
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aligned& operator=(aligned const&) = default;
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aligned& operator=(aligned&&) = default;
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template <
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typename S = T,
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std::enable_if_t<std::is_copy_assignable<S>::value, int> = 0>
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aligned& operator=(T const& value) noexcept(
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std::is_nothrow_copy_assignable<T>::value) {
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value_ = value;
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return *this;
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}
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template <
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typename S = T,
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std::enable_if_t<std::is_move_assignable<S>::value, int> = 0>
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aligned& operator=(T&& value) noexcept(
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std::is_nothrow_move_assignable<T>::value) {
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value_ = std::move(value);
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return *this;
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}
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T* get() noexcept {
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return &value_;
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}
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T const* get() const noexcept {
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return &value_;
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}
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T* operator->() noexcept {
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return &value_;
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}
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T const* operator->() const noexcept {
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return &value_;
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}
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T& operator*() noexcept {
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return value_;
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}
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T const& operator*() const noexcept {
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return value_;
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}
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private:
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alignas(Align) T value_;
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};
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template <typename T>
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using cacheline_aligned = aligned<
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T,
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(cacheline_align_v < alignof(T) ? alignof(T) : cacheline_align_v)>;
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} // namespace folly
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