1// Utility functions for uses-allocator construction -*- C++ -*-
2
3// Copyright (C) 2019-2021 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 template<typename _Tp>
46 inline constexpr bool __is_pair = false;
47 template<typename _Tp, typename _Up>
48 inline constexpr bool __is_pair<pair<_Tp, _Up>> = true;
49 template<typename _Tp, typename _Up>
50 inline constexpr bool __is_pair<const pair<_Tp, _Up>> = true;
51
52 template<typename _Tp>
53 concept _Std_pair = __is_pair<_Tp>;
54
55/** @addtogroup allocators
56 * @{
57 */
58
59// Not specified by C++20, used internally
60#define __cpp_lib_make_obj_using_allocator 201811L
61
62 template<typename _Tp, typename _Alloc, typename... _Args>
63 constexpr auto
64 uses_allocator_construction_args(const _Alloc& __a,
65 _Args&&... __args) noexcept
66 requires (! _Std_pair<_Tp>)
67 {
68 if constexpr (uses_allocator_v<remove_cv_t<_Tp>, _Alloc>)
69 {
70 if constexpr (is_constructible_v<_Tp, allocator_arg_t,
71 const _Alloc&, _Args...>)
72 {
73 return tuple<allocator_arg_t, const _Alloc&, _Args&&...>(
74 allocator_arg, __a, std::forward<_Args>(__args)...);
75 }
76 else
77 {
78 static_assert(is_constructible_v<_Tp, _Args..., const _Alloc&>,
79 "construction with an allocator must be possible"
80 " if uses_allocator is true");
81
82 return tuple<_Args&&..., const _Alloc&>(
83 std::forward<_Args>(__args)..., __a);
84 }
85 }
86 else
87 {
88 static_assert(is_constructible_v<_Tp, _Args...>);
89
90 return tuple<_Args&&...>(std::forward<_Args>(__args)...);
91 }
92 }
93
94 template<_Std_pair _Tp, typename _Alloc, typename _Tuple1, typename _Tuple2>
95 constexpr auto
96 uses_allocator_construction_args(const _Alloc& __a, piecewise_construct_t,
97 _Tuple1&& __x, _Tuple2&& __y) noexcept;
98
99 template<_Std_pair _Tp, typename _Alloc>
100 constexpr auto
101 uses_allocator_construction_args(const _Alloc&) noexcept;
102
103 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp>
104 constexpr auto
105 uses_allocator_construction_args(const _Alloc&, _Up&&, _Vp&&) noexcept;
106
107 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp>
108 constexpr auto
109 uses_allocator_construction_args(const _Alloc&,
110 const pair<_Up, _Vp>&) noexcept;
111
112 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp>
113 constexpr auto
114 uses_allocator_construction_args(const _Alloc&, pair<_Up, _Vp>&&) noexcept;
115
116 template<_Std_pair _Tp, typename _Alloc, typename _Tuple1, typename _Tuple2>
117 constexpr auto
118 uses_allocator_construction_args(const _Alloc& __a, piecewise_construct_t,
119 _Tuple1&& __x, _Tuple2&& __y) noexcept
120 {
121 using _Tp1 = typename _Tp::first_type;
122 using _Tp2 = typename _Tp::second_type;
123
124 return std::make_tuple(piecewise_construct,
125 std::apply([&__a](auto&&... __args1) {
126 return std::uses_allocator_construction_args<_Tp1>(
127 __a, std::forward<decltype(__args1)>(__args1)...);
128 }, std::forward<_Tuple1>(__x)),
129 std::apply([&__a](auto&&... __args2) {
130 return std::uses_allocator_construction_args<_Tp2>(
131 __a, std::forward<decltype(__args2)>(__args2)...);
132 }, std::forward<_Tuple2>(__y)));
133 }
134
135 template<_Std_pair _Tp, typename _Alloc>
136 constexpr auto
137 uses_allocator_construction_args(const _Alloc& __a) noexcept
138 {
139 using _Tp1 = typename _Tp::first_type;
140 using _Tp2 = typename _Tp::second_type;
141
142 return std::make_tuple(piecewise_construct,
143 std::uses_allocator_construction_args<_Tp1>(__a),
144 std::uses_allocator_construction_args<_Tp2>(__a));
145 }
146
147 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp>
148 constexpr auto
149 uses_allocator_construction_args(const _Alloc& __a, _Up&& __u, _Vp&& __v)
150 noexcept
151 {
152 using _Tp1 = typename _Tp::first_type;
153 using _Tp2 = typename _Tp::second_type;
154
155 return std::make_tuple(piecewise_construct,
156 std::uses_allocator_construction_args<_Tp1>(__a,
157 std::forward<_Up>(__u)),
158 std::uses_allocator_construction_args<_Tp2>(__a,
159 std::forward<_Vp>(__v)));
160 }
161
162 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp>
163 constexpr auto
164 uses_allocator_construction_args(const _Alloc& __a,
165 const pair<_Up, _Vp>& __pr) noexcept
166 {
167 using _Tp1 = typename _Tp::first_type;
168 using _Tp2 = typename _Tp::second_type;
169
170 return std::make_tuple(piecewise_construct,
171 std::uses_allocator_construction_args<_Tp1>(__a, __pr.first),
172 std::uses_allocator_construction_args<_Tp2>(__a, __pr.second));
173 }
174
175 template<_Std_pair _Tp, typename _Alloc, typename _Up, typename _Vp>
176 constexpr auto
177 uses_allocator_construction_args(const _Alloc& __a,
178 pair<_Up, _Vp>&& __pr) noexcept
179 {
180 using _Tp1 = typename _Tp::first_type;
181 using _Tp2 = typename _Tp::second_type;
182
183 // _GLIBCXX_RESOLVE_LIB_DEFECTS
184 // 3527. uses_allocator_construction_args handles rvalue pairs
185 // of rvalue references incorrectly
186 return std::make_tuple(piecewise_construct,
187 std::uses_allocator_construction_args<_Tp1>(__a,
188 std::get<0>(std::move(__pr))),
189 std::uses_allocator_construction_args<_Tp2>(__a,
190 std::get<1>(std::move(__pr))));
191 }
192
193 template<typename _Tp, typename _Alloc, typename... _Args>
194 constexpr _Tp
195 make_obj_using_allocator(const _Alloc& __a, _Args&&... __args)
196 {
197 return std::make_from_tuple<_Tp>(
198 std::uses_allocator_construction_args<_Tp>(__a,
199 std::forward<_Args>(__args)...));
200 }
201
202 template<typename _Tp, typename _Alloc, typename... _Args>
203 constexpr _Tp*
204 uninitialized_construct_using_allocator(_Tp* __p, const _Alloc& __a,
205 _Args&&... __args)
206 {
207 return std::apply([&](auto&&... __xs) {
208 return std::construct_at(__p, std::forward<decltype(__xs)>(__xs)...);
209 }, std::uses_allocator_construction_args<_Tp>(__a,
210 std::forward<_Args>(__args)...));
211 }
212/// @}
213_GLIBCXX_END_NAMESPACE_VERSION
214} // namespace std
215#endif // C++20
216#endif // _USES_ALLOCATOR_ARGS
217

source code of include/c++/11/bits/uses_allocator_args.h