Yi Kong | 878f994 | 2023-12-13 12:55:04 +0900 | [diff] [blame^] | 1 | // -*- C++ -*- |
| 2 | //===----------------------------------------------------------------------===// |
| 3 | // |
| 4 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 5 | // See https://llvm.org/LICENSE.txt for license information. |
| 6 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 7 | // |
| 8 | //===----------------------------------------------------------------------===// |
| 9 | |
| 10 | #ifndef _LIBCPP___MEMORY_COMPRESSED_PAIR_H |
| 11 | #define _LIBCPP___MEMORY_COMPRESSED_PAIR_H |
| 12 | |
| 13 | #include <__config> |
| 14 | #include <__fwd/get.h> |
| 15 | #include <__fwd/tuple.h> |
| 16 | #include <__tuple/tuple_indices.h> |
| 17 | #include <__type_traits/decay.h> |
| 18 | #include <__type_traits/dependent_type.h> |
| 19 | #include <__type_traits/enable_if.h> |
| 20 | #include <__type_traits/is_default_constructible.h> |
| 21 | #include <__type_traits/is_empty.h> |
| 22 | #include <__type_traits/is_final.h> |
| 23 | #include <__type_traits/is_same.h> |
| 24 | #include <__type_traits/is_swappable.h> |
| 25 | #include <__utility/forward.h> |
| 26 | #include <__utility/move.h> |
| 27 | #include <__utility/piecewise_construct.h> |
| 28 | #include <cstddef> |
| 29 | |
| 30 | #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| 31 | # pragma GCC system_header |
| 32 | #endif |
| 33 | |
| 34 | _LIBCPP_PUSH_MACROS |
| 35 | #include <__undef_macros> |
| 36 | |
| 37 | _LIBCPP_BEGIN_NAMESPACE_STD |
| 38 | |
| 39 | // Tag used to default initialize one or both of the pair's elements. |
| 40 | struct __default_init_tag {}; |
| 41 | struct __value_init_tag {}; |
| 42 | |
| 43 | template <class _Tp, int _Idx, bool _CanBeEmptyBase = is_empty<_Tp>::value && !__libcpp_is_final<_Tp>::value> |
| 44 | struct __compressed_pair_elem { |
| 45 | using _ParamT = _Tp; |
| 46 | using reference = _Tp&; |
| 47 | using const_reference = const _Tp&; |
| 48 | |
| 49 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR explicit __compressed_pair_elem(__default_init_tag) {} |
| 50 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR explicit __compressed_pair_elem(__value_init_tag) : __value_() {} |
| 51 | |
| 52 | template <class _Up, class = __enable_if_t<!is_same<__compressed_pair_elem, __decay_t<_Up> >::value> > |
| 53 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR |
| 54 | explicit __compressed_pair_elem(_Up&& __u) : __value_(std::forward<_Up>(__u)) {} |
| 55 | |
| 56 | #ifndef _LIBCPP_CXX03_LANG |
| 57 | template <class... _Args, size_t... _Indices> |
| 58 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 |
| 59 | explicit __compressed_pair_elem(piecewise_construct_t, tuple<_Args...> __args, __tuple_indices<_Indices...>) |
| 60 | : __value_(std::forward<_Args>(std::get<_Indices>(__args))...) {} |
| 61 | #endif |
| 62 | |
| 63 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 reference __get() _NOEXCEPT { return __value_; } |
| 64 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR const_reference __get() const _NOEXCEPT { return __value_; } |
| 65 | |
| 66 | private: |
| 67 | _Tp __value_; |
| 68 | }; |
| 69 | |
| 70 | template <class _Tp, int _Idx> |
| 71 | struct __compressed_pair_elem<_Tp, _Idx, true> : private _Tp { |
| 72 | using _ParamT = _Tp; |
| 73 | using reference = _Tp&; |
| 74 | using const_reference = const _Tp&; |
| 75 | using __value_type = _Tp; |
| 76 | |
| 77 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR explicit __compressed_pair_elem() = default; |
| 78 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR explicit __compressed_pair_elem(__default_init_tag) {} |
| 79 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR explicit __compressed_pair_elem(__value_init_tag) : __value_type() {} |
| 80 | |
| 81 | template <class _Up, class = __enable_if_t<!is_same<__compressed_pair_elem, __decay_t<_Up> >::value> > |
| 82 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR |
| 83 | explicit __compressed_pair_elem(_Up&& __u) : __value_type(std::forward<_Up>(__u)) {} |
| 84 | |
| 85 | #ifndef _LIBCPP_CXX03_LANG |
| 86 | template <class... _Args, size_t... _Indices> |
| 87 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 |
| 88 | __compressed_pair_elem(piecewise_construct_t, tuple<_Args...> __args, __tuple_indices<_Indices...>) |
| 89 | : __value_type(std::forward<_Args>(std::get<_Indices>(__args))...) {} |
| 90 | #endif |
| 91 | |
| 92 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 reference __get() _NOEXCEPT { return *this; } |
| 93 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR const_reference __get() const _NOEXCEPT { return *this; } |
| 94 | }; |
| 95 | |
| 96 | template <class _T1, class _T2> |
| 97 | class __compressed_pair : private __compressed_pair_elem<_T1, 0>, |
| 98 | private __compressed_pair_elem<_T2, 1> { |
| 99 | public: |
| 100 | // NOTE: This static assert should never fire because __compressed_pair |
| 101 | // is *almost never* used in a scenario where it's possible for T1 == T2. |
| 102 | // (The exception is std::function where it is possible that the function |
| 103 | // object and the allocator have the same type). |
| 104 | static_assert((!is_same<_T1, _T2>::value), |
| 105 | "__compressed_pair cannot be instantiated when T1 and T2 are the same type; " |
| 106 | "The current implementation is NOT ABI-compatible with the previous implementation for this configuration"); |
| 107 | |
| 108 | using _Base1 _LIBCPP_NODEBUG = __compressed_pair_elem<_T1, 0>; |
| 109 | using _Base2 _LIBCPP_NODEBUG = __compressed_pair_elem<_T2, 1>; |
| 110 | |
| 111 | template <bool _Dummy = true, |
| 112 | class = __enable_if_t< |
| 113 | __dependent_type<is_default_constructible<_T1>, _Dummy>::value && |
| 114 | __dependent_type<is_default_constructible<_T2>, _Dummy>::value |
| 115 | > |
| 116 | > |
| 117 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR |
| 118 | explicit __compressed_pair() : _Base1(__value_init_tag()), _Base2(__value_init_tag()) {} |
| 119 | |
| 120 | template <class _U1, class _U2> |
| 121 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR |
| 122 | explicit __compressed_pair(_U1&& __t1, _U2&& __t2) : _Base1(std::forward<_U1>(__t1)), _Base2(std::forward<_U2>(__t2)) {} |
| 123 | |
| 124 | #ifndef _LIBCPP_CXX03_LANG |
| 125 | template <class... _Args1, class... _Args2> |
| 126 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 |
| 127 | explicit __compressed_pair(piecewise_construct_t __pc, tuple<_Args1...> __first_args, |
| 128 | tuple<_Args2...> __second_args) |
| 129 | : _Base1(__pc, std::move(__first_args), typename __make_tuple_indices<sizeof...(_Args1)>::type()), |
| 130 | _Base2(__pc, std::move(__second_args), typename __make_tuple_indices<sizeof...(_Args2)>::type()) {} |
| 131 | #endif |
| 132 | |
| 133 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 |
| 134 | typename _Base1::reference first() _NOEXCEPT { |
| 135 | return static_cast<_Base1&>(*this).__get(); |
| 136 | } |
| 137 | |
| 138 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR |
| 139 | typename _Base1::const_reference first() const _NOEXCEPT { |
| 140 | return static_cast<_Base1 const&>(*this).__get(); |
| 141 | } |
| 142 | |
| 143 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 |
| 144 | typename _Base2::reference second() _NOEXCEPT { |
| 145 | return static_cast<_Base2&>(*this).__get(); |
| 146 | } |
| 147 | |
| 148 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR |
| 149 | typename _Base2::const_reference second() const _NOEXCEPT { |
| 150 | return static_cast<_Base2 const&>(*this).__get(); |
| 151 | } |
| 152 | |
| 153 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR static |
| 154 | _Base1* __get_first_base(__compressed_pair* __pair) _NOEXCEPT { |
| 155 | return static_cast<_Base1*>(__pair); |
| 156 | } |
| 157 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR static |
| 158 | _Base2* __get_second_base(__compressed_pair* __pair) _NOEXCEPT { |
| 159 | return static_cast<_Base2*>(__pair); |
| 160 | } |
| 161 | |
| 162 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 |
| 163 | void swap(__compressed_pair& __x) |
| 164 | _NOEXCEPT_(__is_nothrow_swappable<_T1>::value && __is_nothrow_swappable<_T2>::value) { |
| 165 | using std::swap; |
| 166 | swap(first(), __x.first()); |
| 167 | swap(second(), __x.second()); |
| 168 | } |
| 169 | }; |
| 170 | |
| 171 | template <class _T1, class _T2> |
| 172 | inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 |
| 173 | void swap(__compressed_pair<_T1, _T2>& __x, __compressed_pair<_T1, _T2>& __y) |
| 174 | _NOEXCEPT_(__is_nothrow_swappable<_T1>::value && __is_nothrow_swappable<_T2>::value) { |
| 175 | __x.swap(__y); |
| 176 | } |
| 177 | |
| 178 | _LIBCPP_END_NAMESPACE_STD |
| 179 | |
| 180 | _LIBCPP_POP_MACROS |
| 181 | |
| 182 | #endif // _LIBCPP___MEMORY_COMPRESSED_PAIR_H |