1 | // Uses-allocator Construction -*- C++ -*- |
2 | |
3 | // Copyright (C) 2010-2024 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_H |
31 | #define _USES_ALLOCATOR_H 1 |
32 | |
33 | #if __cplusplus < 201103L |
34 | # include <bits/c++0x_warning.h> |
35 | #else |
36 | |
37 | #include <type_traits> |
38 | #include <bits/move.h> |
39 | |
40 | namespace std _GLIBCXX_VISIBILITY(default) |
41 | { |
42 | _GLIBCXX_BEGIN_NAMESPACE_VERSION |
43 | /// @cond undocumented |
44 | |
45 | // This is used for std::experimental::erased_type from Library Fundamentals. |
46 | struct __erased_type { }; |
47 | |
48 | // This also supports the "type-erased allocator" protocol from the |
49 | // Library Fundamentals TS, where allocator_type is erased_type. |
50 | // The second condition will always be false for types not using the TS. |
51 | template<typename _Alloc, typename _Tp> |
52 | using __is_erased_or_convertible |
53 | = __or_<is_convertible<_Alloc, _Tp>, is_same<_Tp, __erased_type>>; |
54 | |
55 | /// [allocator.tag] |
56 | struct allocator_arg_t { explicit allocator_arg_t() = default; }; |
57 | |
58 | _GLIBCXX17_INLINE constexpr allocator_arg_t allocator_arg = |
59 | allocator_arg_t(); |
60 | |
61 | template<typename _Tp, typename _Alloc, typename = __void_t<>> |
62 | struct __uses_allocator_helper |
63 | : false_type { }; |
64 | |
65 | template<typename _Tp, typename _Alloc> |
66 | struct __uses_allocator_helper<_Tp, _Alloc, |
67 | __void_t<typename _Tp::allocator_type>> |
68 | : __is_erased_or_convertible<_Alloc, typename _Tp::allocator_type>::type |
69 | { }; |
70 | |
71 | /// [allocator.uses.trait] |
72 | template<typename _Tp, typename _Alloc> |
73 | struct uses_allocator |
74 | : __uses_allocator_helper<_Tp, _Alloc>::type |
75 | { }; |
76 | |
77 | struct __uses_alloc_base { }; |
78 | |
79 | struct __uses_alloc0 : __uses_alloc_base |
80 | { |
81 | struct _Sink { void _GLIBCXX20_CONSTEXPR operator=(const void*) { } } _M_a; |
82 | }; |
83 | |
84 | template<typename _Alloc> |
85 | struct __uses_alloc1 : __uses_alloc_base { const _Alloc* _M_a; }; |
86 | |
87 | template<typename _Alloc> |
88 | struct __uses_alloc2 : __uses_alloc_base { const _Alloc* _M_a; }; |
89 | |
90 | template<bool, typename _Tp, typename _Alloc, typename... _Args> |
91 | struct __uses_alloc; |
92 | |
93 | template<typename _Tp, typename _Alloc, typename... _Args> |
94 | struct __uses_alloc<true, _Tp, _Alloc, _Args...> |
95 | : __conditional_t< |
96 | is_constructible<_Tp, allocator_arg_t, const _Alloc&, _Args...>::value, |
97 | __uses_alloc1<_Alloc>, |
98 | __uses_alloc2<_Alloc>> |
99 | { |
100 | // _GLIBCXX_RESOLVE_LIB_DEFECTS |
101 | // 2586. Wrong value category used in scoped_allocator_adaptor::construct |
102 | static_assert(__or_< |
103 | is_constructible<_Tp, allocator_arg_t, const _Alloc&, _Args...>, |
104 | is_constructible<_Tp, _Args..., const _Alloc&>>::value, |
105 | "construction with an allocator must be possible" |
106 | " if uses_allocator is true" ); |
107 | }; |
108 | |
109 | template<typename _Tp, typename _Alloc, typename... _Args> |
110 | struct __uses_alloc<false, _Tp, _Alloc, _Args...> |
111 | : __uses_alloc0 { }; |
112 | |
113 | template<typename _Tp, typename _Alloc, typename... _Args> |
114 | using __uses_alloc_t = |
115 | __uses_alloc<uses_allocator<_Tp, _Alloc>::value, _Tp, _Alloc, _Args...>; |
116 | |
117 | template<typename _Tp, typename _Alloc, typename... _Args> |
118 | _GLIBCXX20_CONSTEXPR |
119 | inline __uses_alloc_t<_Tp, _Alloc, _Args...> |
120 | __use_alloc(const _Alloc& __a) |
121 | { |
122 | __uses_alloc_t<_Tp, _Alloc, _Args...> __ret; |
123 | __ret._M_a = std::__addressof(__a); |
124 | return __ret; |
125 | } |
126 | |
127 | template<typename _Tp, typename _Alloc, typename... _Args> |
128 | void |
129 | __use_alloc(const _Alloc&&) = delete; |
130 | |
131 | #if __cplusplus > 201402L |
132 | template <typename _Tp, typename _Alloc> |
133 | inline constexpr bool uses_allocator_v = |
134 | uses_allocator<_Tp, _Alloc>::value; |
135 | #endif // C++17 |
136 | |
137 | template<template<typename...> class _Predicate, |
138 | typename _Tp, typename _Alloc, typename... _Args> |
139 | struct __is_uses_allocator_predicate |
140 | : __conditional_t<uses_allocator<_Tp, _Alloc>::value, |
141 | __or_<_Predicate<_Tp, allocator_arg_t, _Alloc, _Args...>, |
142 | _Predicate<_Tp, _Args..., _Alloc>>, |
143 | _Predicate<_Tp, _Args...>> { }; |
144 | |
145 | template<typename _Tp, typename _Alloc, typename... _Args> |
146 | struct __is_uses_allocator_constructible |
147 | : __is_uses_allocator_predicate<is_constructible, _Tp, _Alloc, _Args...> |
148 | { }; |
149 | |
150 | #if __cplusplus >= 201402L |
151 | template<typename _Tp, typename _Alloc, typename... _Args> |
152 | _GLIBCXX17_INLINE constexpr bool __is_uses_allocator_constructible_v = |
153 | __is_uses_allocator_constructible<_Tp, _Alloc, _Args...>::value; |
154 | #endif // C++14 |
155 | |
156 | template<typename _Tp, typename _Alloc, typename... _Args> |
157 | struct __is_nothrow_uses_allocator_constructible |
158 | : __is_uses_allocator_predicate<is_nothrow_constructible, |
159 | _Tp, _Alloc, _Args...> |
160 | { }; |
161 | |
162 | |
163 | #if __cplusplus >= 201402L |
164 | template<typename _Tp, typename _Alloc, typename... _Args> |
165 | _GLIBCXX17_INLINE constexpr bool |
166 | __is_nothrow_uses_allocator_constructible_v = |
167 | __is_nothrow_uses_allocator_constructible<_Tp, _Alloc, _Args...>::value; |
168 | #endif // C++14 |
169 | |
170 | template<typename _Tp, typename... _Args> |
171 | void __uses_allocator_construct_impl(__uses_alloc0, _Tp* __ptr, |
172 | _Args&&... __args) |
173 | { ::new ((void*)__ptr) _Tp(std::forward<_Args>(__args)...); } |
174 | |
175 | template<typename _Tp, typename _Alloc, typename... _Args> |
176 | void __uses_allocator_construct_impl(__uses_alloc1<_Alloc> __a, _Tp* __ptr, |
177 | _Args&&... __args) |
178 | { |
179 | ::new ((void*)__ptr) _Tp(allocator_arg, *__a._M_a, |
180 | std::forward<_Args>(__args)...); |
181 | } |
182 | |
183 | template<typename _Tp, typename _Alloc, typename... _Args> |
184 | void __uses_allocator_construct_impl(__uses_alloc2<_Alloc> __a, _Tp* __ptr, |
185 | _Args&&... __args) |
186 | { ::new ((void*)__ptr) _Tp(std::forward<_Args>(__args)..., *__a._M_a); } |
187 | |
188 | template<typename _Tp, typename _Alloc, typename... _Args> |
189 | void __uses_allocator_construct(const _Alloc& __a, _Tp* __ptr, |
190 | _Args&&... __args) |
191 | { |
192 | std::__uses_allocator_construct_impl( |
193 | std::__use_alloc<_Tp, _Alloc, _Args...>(__a), __ptr, |
194 | std::forward<_Args>(__args)...); |
195 | } |
196 | |
197 | /// @endcond |
198 | _GLIBCXX_END_NAMESPACE_VERSION |
199 | } // namespace std |
200 | |
201 | #endif |
202 | #endif |
203 | |