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1 // Utility functions for uses-allocator construction -*- C++ -*- 2 3 // Copyright (C) 2019-2025 Free Software Foundation, Inc. 4 // 5 // This file is part of the GNU ISO C++ Library. This library is free 6 // software; you can redistribute it and/or modify it under the 7 // terms of the GNU General Public License as published by the 8 // Free Software Foundation; either version 3, or (at your option) 9 // any later version. 10 11 // This library is distributed in the hope that it will be useful, 12 // but WITHOUT ANY WARRANTY; without even the implied warranty of 13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 // GNU General Public License for more details. 15 16 // Under Section 7 of GPL version 3, you are granted additional 17 // permissions described in the GCC Runtime Library Exception, version 18 // 3.1, as published by the Free Software Foundation. 19 20 // You should have received a copy of the GNU General Public License and 21 // a copy of the GCC Runtime Library Exception along with this program; 22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 // <http://www.gnu.org/licenses/>. 24 25 /** @file include/bits/uses_allocator_args.h 26 * This is an internal header file, included by other library headers. 27 * Do not attempt to use it directly. @headername{memory} 28 */ 29 30 #ifndef _USES_ALLOCATOR_ARGS 31 #define _USES_ALLOCATOR_ARGS 1 32 33 #ifdef _GLIBCXX_SYSHDR 34 #pragma GCC system_header 35 #endif 36 37 #include <bits/version.h> 38 39 #ifdef __glibcxx_make_obj_using_allocator // C++ >= 20 && concepts 40 #include <new> // for placement operator new 41 #include <tuple> // for tuple, make_tuple, make_from_tuple 42 #include <bits/stl_construct.h> // construct_at 43 #include <bits/stl_pair.h> // pair 44 45 namespace std _GLIBCXX_VISIBILITY(default) 46 { 47 _GLIBCXX_BEGIN_NAMESPACE_VERSION 48 49 template<typename _Tp> 50 concept _Std_pair = __is_pair<remove_cv_t<_Tp>>; 51 52 /** @addtogroup allocators 53 * @{ 54 */ 55 template<typename _Tp, typename _Alloc, typename... _Args> 56 constexpr auto 57 uses_allocator_construction_args(const _Alloc& __a, 58 _Args&&... __args) noexcept 59 requires (! _Std_pair<_Tp>) 60 { 61 if constexpr (uses_allocator_v<remove_cv_t<_Tp>, _Alloc>) 62 { 63 if constexpr (is_constructible_v<_Tp, allocator_arg_t, 64 const _Alloc&, _Args...>) 65 { 66 return tuple<allocator_arg_t, const _Alloc&, _Args&&...>( 67 allocator_arg, __a, std::forward<_Args>(__args)...); 68 } 69 else 70 { 71 static_assert(is_constructible_v<_Tp, _Args..., const _Alloc&>, 72 "construction with an allocator must be possible" 73 " if uses_allocator is true"); 74 75 return tuple<_Args&&..., const _Alloc&>( 76 std::forward<_Args>(__args)..., __a); 77 } 78 } 79 else 80 { 81 static_assert(is_constructible_v<_Tp, _Args...>); 82 83 return tuple<_Args&&...>(std::forward<_Args>(__args)...); 84 } 85 } 86 87 template<_Std_pair _Tp, typename _Alloc, typename _Tuple1, typename _Tuple2> 88 constexpr auto 89 uses_allocator_construction_args(const _Alloc& __a, piecewise_construct_t, 90 _Tuple1&& __x, _Tuple2&& __y) noexcept; 91 92 template<_Std_pair _Tp, typename _Alloc> 93 constexpr auto 94 uses_allocator_construction_args(const _Alloc&) noexcept; 95 96 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp> 97 constexpr auto 98 uses_allocator_construction_args(const _Alloc&, _Up&&, _Vp&&) noexcept; 99 100 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp> 101 constexpr auto 102 uses_allocator_construction_args(const _Alloc&, 103 const pair<_Up, _Vp>&) noexcept; 104 105 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp> 106 constexpr auto 107 uses_allocator_construction_args(const _Alloc&, pair<_Up, _Vp>&&) noexcept; 108 109 #if __cplusplus > 202002L 110 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp> 111 constexpr auto 112 uses_allocator_construction_args(const _Alloc&, 113 pair<_Up, _Vp>&) noexcept; 114 115 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp> 116 constexpr auto 117 uses_allocator_construction_args(const _Alloc&, const pair<_Up, _Vp>&&) noexcept; 118 #endif // C++23 119 120 template<_Std_pair _Tp, typename _Alloc, typename _Tuple1, typename _Tuple2> 121 constexpr auto 122 uses_allocator_construction_args(const _Alloc& __a, piecewise_construct_t, 123 _Tuple1&& __x, _Tuple2&& __y) noexcept 124 { 125 using _Tp1 = typename _Tp::first_type; 126 using _Tp2 = typename _Tp::second_type; 127 128 return std::make_tuple(piecewise_construct, 129 std::apply([&__a](auto&&... __args1) { 130 return std::uses_allocator_construction_args<_Tp1>( 131 __a, std::forward<decltype(__args1)>(__args1)...); 132 }, std::forward<_Tuple1>(__x)), 133 std::apply([&__a](auto&&... __args2) { 134 return std::uses_allocator_construction_args<_Tp2>( 135 __a, std::forward<decltype(__args2)>(__args2)...); 136 }, std::forward<_Tuple2>(__y))); 137 } 138 139 template<_Std_pair _Tp, typename _Alloc> 140 constexpr auto 141 uses_allocator_construction_args(const _Alloc& __a) noexcept 142 { 143 using _Tp1 = typename _Tp::first_type; 144 using _Tp2 = typename _Tp::second_type; 145 146 return std::make_tuple(piecewise_construct, 147 std::uses_allocator_construction_args<_Tp1>(__a), 148 std::uses_allocator_construction_args<_Tp2>(__a)); 149 } 150 151 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp> 152 constexpr auto 153 uses_allocator_construction_args(const _Alloc& __a, _Up&& __u, _Vp&& __v) 154 noexcept 155 { 156 using _Tp1 = typename _Tp::first_type; 157 using _Tp2 = typename _Tp::second_type; 158 159 return std::make_tuple(piecewise_construct, 160 std::uses_allocator_construction_args<_Tp1>(__a, 161 std::forward<_Up>(__u)), 162 std::uses_allocator_construction_args<_Tp2>(__a, 163 std::forward<_Vp>(__v))); 164 } 165 166 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp> 167 constexpr auto 168 uses_allocator_construction_args(const _Alloc& __a, 169 const pair<_Up, _Vp>& __pr) noexcept 170 { 171 using _Tp1 = typename _Tp::first_type; 172 using _Tp2 = typename _Tp::second_type; 173 174 return std::make_tuple(piecewise_construct, 175 std::uses_allocator_construction_args<_Tp1>(__a, __pr.first), 176 std::uses_allocator_construction_args<_Tp2>(__a, __pr.second)); 177 } 178 179 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp> 180 constexpr auto 181 uses_allocator_construction_args(const _Alloc& __a, 182 pair<_Up, _Vp>&& __pr) noexcept 183 { 184 using _Tp1 = typename _Tp::first_type; 185 using _Tp2 = typename _Tp::second_type; 186 187 // _GLIBCXX_RESOLVE_LIB_DEFECTS 188 // 3527. uses_allocator_construction_args handles rvalue pairs 189 // of rvalue references incorrectly 190 return std::make_tuple(piecewise_construct, 191 std::uses_allocator_construction_args<_Tp1>(__a, 192 std::get<0>(std::move(__pr))), 193 std::uses_allocator_construction_args<_Tp2>(__a, 194 std::get<1>(std::move(__pr)))); 195 } 196 197 #if __cplusplus > 202002L 198 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp> 199 constexpr auto 200 uses_allocator_construction_args(const _Alloc& __a, 201 pair<_Up, _Vp>& __pr) noexcept 202 { 203 using _Tp1 = typename _Tp::first_type; 204 using _Tp2 = typename _Tp::second_type; 205 206 return std::make_tuple(piecewise_construct, 207 std::uses_allocator_construction_args<_Tp1>(__a, __pr.first), 208 std::uses_allocator_construction_args<_Tp2>(__a, __pr.second)); 209 } 210 211 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp> 212 constexpr auto 213 uses_allocator_construction_args(const _Alloc& __a, 214 const pair<_Up, _Vp>&& __pr) noexcept 215 { 216 using _Tp1 = typename _Tp::first_type; 217 using _Tp2 = typename _Tp::second_type; 218 219 return std::make_tuple(piecewise_construct, 220 std::uses_allocator_construction_args<_Tp1>(__a, 221 std::get<0>(std::move(__pr))), 222 std::uses_allocator_construction_args<_Tp2>(__a, 223 std::get<1>(std::move(__pr)))); 224 } 225 #endif // C++23 226 227 template<typename _Tp, typename _Alloc, typename... _Args> 228 constexpr _Tp 229 make_obj_using_allocator(const _Alloc& __a, _Args&&... __args) 230 { 231 return std::make_from_tuple<_Tp>( 232 std::uses_allocator_construction_args<_Tp>(__a, 233 std::forward<_Args>(__args)...)); 234 } 235 236 template<typename _Tp, typename _Alloc, typename... _Args> 237 constexpr _Tp* 238 uninitialized_construct_using_allocator(_Tp* __p, const _Alloc& __a, 239 _Args&&... __args) 240 { 241 return std::apply([&](auto&&... __xs) { 242 return std::construct_at(__p, std::forward<decltype(__xs)>(__xs)...); 243 }, std::uses_allocator_construction_args<_Tp>(__a, 244 std::forward<_Args>(__args)...)); 245 } 246 /// @} 247 _GLIBCXX_END_NAMESPACE_VERSION 248 } // namespace std 249 #endif // __glibcxx_make_obj_using_allocator 250 #endif // _USES_ALLOCATOR_ARGS
