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2adb4b5 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 | // Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you 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 <cstring>
#include <type_traits>
#include <utility>
#include "arrow/util/launder.h"
#include "arrow/util/macros.h"
namespace arrow {
namespace internal {
template <typename T>
class AlignedStorage {
public:
static constexpr bool can_memcpy = std::is_trivial<T>::value;
constexpr T* get() noexcept {
return arrow::internal::launder(reinterpret_cast<T*>(&data_));
}
constexpr const T* get() const noexcept {
// Use fully qualified name to avoid ambiguities with MSVC (ARROW-14800)
return arrow::internal::launder(reinterpret_cast<const T*>(&data_));
}
void destroy() noexcept {
if (!std::is_trivially_destructible<T>::value) {
get()->~T();
}
}
template <typename... A>
void construct(A&&... args) noexcept {
new (&data_) T(std::forward<A>(args)...);
}
template <typename V>
void assign(V&& v) noexcept {
*get() = std::forward<V>(v);
}
void move_construct(AlignedStorage* other) noexcept {
new (&data_) T(std::move(*other->get()));
}
void move_assign(AlignedStorage* other) noexcept { *get() = std::move(*other->get()); }
template <bool CanMemcpy = can_memcpy>
static typename std::enable_if<CanMemcpy>::type move_construct_several(
AlignedStorage* ARROW_RESTRICT src, AlignedStorage* ARROW_RESTRICT dest, size_t n,
size_t memcpy_length) noexcept {
memcpy(dest->get(), src->get(), memcpy_length * sizeof(T));
}
template <bool CanMemcpy = can_memcpy>
static typename std::enable_if<CanMemcpy>::type
move_construct_several_and_destroy_source(AlignedStorage* ARROW_RESTRICT src,
AlignedStorage* ARROW_RESTRICT dest, size_t n,
size_t memcpy_length) noexcept {
memcpy(dest->get(), src->get(), memcpy_length * sizeof(T));
}
template <bool CanMemcpy = can_memcpy>
static typename std::enable_if<!CanMemcpy>::type move_construct_several(
AlignedStorage* ARROW_RESTRICT src, AlignedStorage* ARROW_RESTRICT dest, size_t n,
size_t memcpy_length) noexcept {
for (size_t i = 0; i < n; ++i) {
new (dest[i].get()) T(std::move(*src[i].get()));
}
}
template <bool CanMemcpy = can_memcpy>
static typename std::enable_if<!CanMemcpy>::type
move_construct_several_and_destroy_source(AlignedStorage* ARROW_RESTRICT src,
AlignedStorage* ARROW_RESTRICT dest, size_t n,
size_t memcpy_length) noexcept {
for (size_t i = 0; i < n; ++i) {
new (dest[i].get()) T(std::move(*src[i].get()));
src[i].destroy();
}
}
static void move_construct_several(AlignedStorage* ARROW_RESTRICT src,
AlignedStorage* ARROW_RESTRICT dest,
size_t n) noexcept {
move_construct_several(src, dest, n, n);
}
static void move_construct_several_and_destroy_source(
AlignedStorage* ARROW_RESTRICT src, AlignedStorage* ARROW_RESTRICT dest,
size_t n) noexcept {
move_construct_several_and_destroy_source(src, dest, n, n);
}
static void destroy_several(AlignedStorage* p, size_t n) noexcept {
if (!std::is_trivially_destructible<T>::value) {
for (size_t i = 0; i < n; ++i) {
p[i].destroy();
}
}
}
private:
alignas(T) std::byte data_[sizeof(T)];
};
} // namespace internal
} // namespace arrow
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