libstdc++
uses_allocator_args.h
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1// Utility functions for uses-allocator construction -*- C++ -*-
2
3// Copyright (C) 2019-2023 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#pragma GCC system_header
34
35#if __cplusplus > 201703L && __cpp_concepts
36
37#include <new> // for placement operator new
38#include <tuple> // for tuple, make_tuple, make_from_tuple
39#include <bits/stl_construct.h> // construct_at
40#include <bits/stl_pair.h> // pair
41
42namespace std _GLIBCXX_VISIBILITY(default)
43{
44_GLIBCXX_BEGIN_NAMESPACE_VERSION
45
46 template<typename _Tp>
47 concept _Std_pair = __is_pair<remove_cv_t<_Tp>>;
48
49/** @addtogroup allocators
50 * @{
51 */
52
53// Not specified by C++20, used internally
54#define __cpp_lib_make_obj_using_allocator 201811L
55
56 template<typename _Tp, typename _Alloc, typename... _Args>
57 constexpr auto
58 uses_allocator_construction_args(const _Alloc& __a,
59 _Args&&... __args) noexcept
60 requires (! _Std_pair<_Tp>)
61 {
62 if constexpr (uses_allocator_v<remove_cv_t<_Tp>, _Alloc>)
63 {
64 if constexpr (is_constructible_v<_Tp, allocator_arg_t,
65 const _Alloc&, _Args...>)
66 {
67 return tuple<allocator_arg_t, const _Alloc&, _Args&&...>(
68 allocator_arg, __a, std::forward<_Args>(__args)...);
69 }
70 else
71 {
72 static_assert(is_constructible_v<_Tp, _Args..., const _Alloc&>,
73 "construction with an allocator must be possible"
74 " if uses_allocator is true");
75
76 return tuple<_Args&&..., const _Alloc&>(
77 std::forward<_Args>(__args)..., __a);
78 }
79 }
80 else
81 {
82 static_assert(is_constructible_v<_Tp, _Args...>);
83
84 return tuple<_Args&&...>(std::forward<_Args>(__args)...);
85 }
86 }
87
88 template<_Std_pair _Tp, typename _Alloc, typename _Tuple1, typename _Tuple2>
89 constexpr auto
90 uses_allocator_construction_args(const _Alloc& __a, piecewise_construct_t,
91 _Tuple1&& __x, _Tuple2&& __y) noexcept;
92
93 template<_Std_pair _Tp, typename _Alloc>
94 constexpr auto
95 uses_allocator_construction_args(const _Alloc&) noexcept;
96
97 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp>
98 constexpr auto
99 uses_allocator_construction_args(const _Alloc&, _Up&&, _Vp&&) noexcept;
100
101 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp>
102 constexpr auto
103 uses_allocator_construction_args(const _Alloc&,
104 const pair<_Up, _Vp>&) noexcept;
105
106 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp>
107 constexpr auto
108 uses_allocator_construction_args(const _Alloc&, pair<_Up, _Vp>&&) noexcept;
109
110#if __cplusplus > 202002L
111 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp>
112 constexpr auto
113 uses_allocator_construction_args(const _Alloc&,
114 pair<_Up, _Vp>&) noexcept;
115
116 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp>
117 constexpr auto
118 uses_allocator_construction_args(const _Alloc&, const pair<_Up, _Vp>&&) noexcept;
119#endif // C++23
120
121 template<_Std_pair _Tp, typename _Alloc, typename _Tuple1, typename _Tuple2>
122 constexpr auto
123 uses_allocator_construction_args(const _Alloc& __a, piecewise_construct_t,
124 _Tuple1&& __x, _Tuple2&& __y) noexcept
125 {
126 using _Tp1 = typename _Tp::first_type;
127 using _Tp2 = typename _Tp::second_type;
128
129 return std::make_tuple(piecewise_construct,
130 std::apply([&__a](auto&&... __args1) {
131 return std::uses_allocator_construction_args<_Tp1>(
132 __a, std::forward<decltype(__args1)>(__args1)...);
133 }, std::forward<_Tuple1>(__x)),
134 std::apply([&__a](auto&&... __args2) {
135 return std::uses_allocator_construction_args<_Tp2>(
136 __a, std::forward<decltype(__args2)>(__args2)...);
137 }, std::forward<_Tuple2>(__y)));
138 }
139
140 template<_Std_pair _Tp, typename _Alloc>
141 constexpr auto
142 uses_allocator_construction_args(const _Alloc& __a) noexcept
143 {
144 using _Tp1 = typename _Tp::first_type;
145 using _Tp2 = typename _Tp::second_type;
146
147 return std::make_tuple(piecewise_construct,
148 std::uses_allocator_construction_args<_Tp1>(__a),
149 std::uses_allocator_construction_args<_Tp2>(__a));
150 }
151
152 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp>
153 constexpr auto
154 uses_allocator_construction_args(const _Alloc& __a, _Up&& __u, _Vp&& __v)
155 noexcept
156 {
157 using _Tp1 = typename _Tp::first_type;
158 using _Tp2 = typename _Tp::second_type;
159
160 return std::make_tuple(piecewise_construct,
161 std::uses_allocator_construction_args<_Tp1>(__a,
162 std::forward<_Up>(__u)),
163 std::uses_allocator_construction_args<_Tp2>(__a,
164 std::forward<_Vp>(__v)));
165 }
166
167 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp>
168 constexpr auto
169 uses_allocator_construction_args(const _Alloc& __a,
170 const pair<_Up, _Vp>& __pr) noexcept
171 {
172 using _Tp1 = typename _Tp::first_type;
173 using _Tp2 = typename _Tp::second_type;
174
175 return std::make_tuple(piecewise_construct,
176 std::uses_allocator_construction_args<_Tp1>(__a, __pr.first),
177 std::uses_allocator_construction_args<_Tp2>(__a, __pr.second));
178 }
179
180 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp>
181 constexpr auto
182 uses_allocator_construction_args(const _Alloc& __a,
183 pair<_Up, _Vp>&& __pr) noexcept
184 {
185 using _Tp1 = typename _Tp::first_type;
186 using _Tp2 = typename _Tp::second_type;
187
188 // _GLIBCXX_RESOLVE_LIB_DEFECTS
189 // 3527. uses_allocator_construction_args handles rvalue pairs
190 // of rvalue references incorrectly
191 return std::make_tuple(piecewise_construct,
192 std::uses_allocator_construction_args<_Tp1>(__a,
193 std::get<0>(std::move(__pr))),
194 std::uses_allocator_construction_args<_Tp2>(__a,
195 std::get<1>(std::move(__pr))));
196 }
197
198#if __cplusplus > 202002L
199 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp>
200 constexpr auto
201 uses_allocator_construction_args(const _Alloc& __a,
202 pair<_Up, _Vp>& __pr) noexcept
203 {
204 using _Tp1 = typename _Tp::first_type;
205 using _Tp2 = typename _Tp::second_type;
206
207 return std::make_tuple(piecewise_construct,
208 std::uses_allocator_construction_args<_Tp1>(__a, __pr.first),
209 std::uses_allocator_construction_args<_Tp2>(__a, __pr.second));
210 }
211
212 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp>
213 constexpr auto
214 uses_allocator_construction_args(const _Alloc& __a,
215 const pair<_Up, _Vp>&& __pr) noexcept
216 {
217 using _Tp1 = typename _Tp::first_type;
218 using _Tp2 = typename _Tp::second_type;
219
220 return std::make_tuple(piecewise_construct,
221 std::uses_allocator_construction_args<_Tp1>(__a,
222 std::get<0>(std::move(__pr))),
223 std::uses_allocator_construction_args<_Tp2>(__a,
224 std::get<1>(std::move(__pr))));
225 }
226#endif // C++23
227
228 template<typename _Tp, typename _Alloc, typename... _Args>
229 constexpr _Tp
230 make_obj_using_allocator(const _Alloc& __a, _Args&&... __args)
231 {
232 return std::make_from_tuple<_Tp>(
233 std::uses_allocator_construction_args<_Tp>(__a,
234 std::forward<_Args>(__args)...));
235 }
236
237 template<typename _Tp, typename _Alloc, typename... _Args>
238 constexpr _Tp*
239 uninitialized_construct_using_allocator(_Tp* __p, const _Alloc& __a,
240 _Args&&... __args)
241 {
242 return std::apply([&](auto&&... __xs) {
243 return std::construct_at(__p, std::forward<decltype(__xs)>(__xs)...);
244 }, std::uses_allocator_construction_args<_Tp>(__a,
245 std::forward<_Args>(__args)...));
246 }
247/// @}
248_GLIBCXX_END_NAMESPACE_VERSION
249} // namespace std
250#endif // C++20
251#endif // _USES_ALLOCATOR_ARGS
std::make_tuple
constexpr tuple< typename __decay_and_strip< _Elements >::__type... > make_tuple(_Elements &&... __args)
Create a tuple containing copies of the arguments.
Definition: tuple:1987
std::move
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
Definition: move.h:104
std::piecewise_construct
constexpr piecewise_construct_t piecewise_construct
Tag for piecewise construction of std::pair objects.
Definition: stl_pair.h:83
std::forward
constexpr _Tp && forward(typename std::remove_reference< _Tp >::type &__t) noexcept
Forward an lvalue.
Definition: move.h:77
std
ISO C++ entities toplevel namespace is std.