1 | // Allocators -*- C++ -*- |
2 | |
3 | // Copyright (C) 2001-2019 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 | /* |
26 | * Copyright (c) 1996-1997 |
27 | * Silicon Graphics Computer Systems, Inc. |
28 | * |
29 | * Permission to use, copy, modify, distribute and sell this software |
30 | * and its documentation for any purpose is hereby granted without fee, |
31 | * provided that the above copyright notice appear in all copies and |
32 | * that both that copyright notice and this permission notice appear |
33 | * in supporting documentation. Silicon Graphics makes no |
34 | * representations about the suitability of this software for any |
35 | * purpose. It is provided "as is" without express or implied warranty. |
36 | */ |
37 | |
38 | /** @file bits/allocator.h |
39 | * This is an internal header file, included by other library headers. |
40 | * Do not attempt to use it directly. @headername{memory} |
41 | */ |
42 | |
43 | #ifndef _ALLOCATOR_H |
44 | #define _ALLOCATOR_H 1 |
45 | |
46 | #include <bits/c++allocator.h> // Define the base class to std::allocator. |
47 | #include <bits/memoryfwd.h> |
48 | #if __cplusplus >= 201103L |
49 | #include <type_traits> |
50 | #endif |
51 | |
52 | #define __cpp_lib_incomplete_container_elements 201505 |
53 | #if __cplusplus >= 201103L |
54 | # define __cpp_lib_allocator_is_always_equal 201411 |
55 | #endif |
56 | |
57 | namespace std _GLIBCXX_VISIBILITY(default) |
58 | { |
59 | _GLIBCXX_BEGIN_NAMESPACE_VERSION |
60 | |
61 | /** |
62 | * @addtogroup allocators |
63 | * @{ |
64 | */ |
65 | |
66 | /// allocator<void> specialization. |
67 | template<> |
68 | class allocator<void> |
69 | { |
70 | public: |
71 | typedef size_t size_type; |
72 | typedef ptrdiff_t difference_type; |
73 | typedef void* pointer; |
74 | typedef const void* const_pointer; |
75 | typedef void value_type; |
76 | |
77 | template<typename _Tp1> |
78 | struct rebind |
79 | { typedef allocator<_Tp1> other; }; |
80 | |
81 | #if __cplusplus >= 201103L |
82 | // _GLIBCXX_RESOLVE_LIB_DEFECTS |
83 | // 2103. std::allocator propagate_on_container_move_assignment |
84 | typedef true_type propagate_on_container_move_assignment; |
85 | |
86 | typedef true_type is_always_equal; |
87 | |
88 | template<typename _Up, typename... _Args> |
89 | void |
90 | construct(_Up* __p, _Args&&... __args) |
91 | noexcept(std::is_nothrow_constructible<_Up, _Args...>::value) |
92 | { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); } |
93 | |
94 | template<typename _Up> |
95 | void |
96 | destroy(_Up* __p) |
97 | noexcept(std::is_nothrow_destructible<_Up>::value) |
98 | { __p->~_Up(); } |
99 | #endif |
100 | }; |
101 | |
102 | /** |
103 | * @brief The @a standard allocator, as per [20.4]. |
104 | * |
105 | * See https://gcc.gnu.org/onlinedocs/libstdc++/manual/memory.html#std.util.memory.allocator |
106 | * for further details. |
107 | * |
108 | * @tparam _Tp Type of allocated object. |
109 | */ |
110 | template<typename _Tp> |
111 | class allocator : public __allocator_base<_Tp> |
112 | { |
113 | public: |
114 | typedef size_t size_type; |
115 | typedef ptrdiff_t difference_type; |
116 | typedef _Tp* pointer; |
117 | typedef const _Tp* const_pointer; |
118 | typedef _Tp& reference; |
119 | typedef const _Tp& const_reference; |
120 | typedef _Tp value_type; |
121 | |
122 | template<typename _Tp1> |
123 | struct rebind |
124 | { typedef allocator<_Tp1> other; }; |
125 | |
126 | #if __cplusplus >= 201103L |
127 | // _GLIBCXX_RESOLVE_LIB_DEFECTS |
128 | // 2103. std::allocator propagate_on_container_move_assignment |
129 | typedef true_type propagate_on_container_move_assignment; |
130 | |
131 | typedef true_type is_always_equal; |
132 | #endif |
133 | |
134 | // _GLIBCXX_RESOLVE_LIB_DEFECTS |
135 | // 3035. std::allocator's constructors should be constexpr |
136 | _GLIBCXX20_CONSTEXPR |
137 | allocator() _GLIBCXX_NOTHROW { } |
138 | |
139 | _GLIBCXX20_CONSTEXPR |
140 | allocator(const allocator& __a) _GLIBCXX_NOTHROW |
141 | : __allocator_base<_Tp>(__a) { } |
142 | |
143 | #if __cplusplus >= 201103L |
144 | // Avoid implicit deprecation. |
145 | allocator& operator=(const allocator&) = default; |
146 | #endif |
147 | |
148 | template<typename _Tp1> |
149 | _GLIBCXX20_CONSTEXPR |
150 | allocator(const allocator<_Tp1>&) _GLIBCXX_NOTHROW { } |
151 | |
152 | ~allocator() _GLIBCXX_NOTHROW { } |
153 | |
154 | friend bool |
155 | operator==(const allocator&, const allocator&) _GLIBCXX_NOTHROW |
156 | { return true; } |
157 | |
158 | friend bool |
159 | operator!=(const allocator&, const allocator&) _GLIBCXX_NOTHROW |
160 | { return false; } |
161 | |
162 | // Inherit everything else. |
163 | }; |
164 | |
165 | template<typename _T1, typename _T2> |
166 | inline bool |
167 | operator==(const allocator<_T1>&, const allocator<_T2>&) |
168 | _GLIBCXX_NOTHROW |
169 | { return true; } |
170 | |
171 | template<typename _T1, typename _T2> |
172 | inline bool |
173 | operator!=(const allocator<_T1>&, const allocator<_T2>&) |
174 | _GLIBCXX_NOTHROW |
175 | { return false; } |
176 | |
177 | // Invalid allocator<cv T> partial specializations. |
178 | // allocator_traits::rebind_alloc can be used to form a valid allocator type. |
179 | template<typename _Tp> |
180 | class allocator<const _Tp> |
181 | { |
182 | public: |
183 | typedef _Tp value_type; |
184 | template<typename _Up> allocator(const allocator<_Up>&) { } |
185 | }; |
186 | |
187 | template<typename _Tp> |
188 | class allocator<volatile _Tp> |
189 | { |
190 | public: |
191 | typedef _Tp value_type; |
192 | template<typename _Up> allocator(const allocator<_Up>&) { } |
193 | }; |
194 | |
195 | template<typename _Tp> |
196 | class allocator<const volatile _Tp> |
197 | { |
198 | public: |
199 | typedef _Tp value_type; |
200 | template<typename _Up> allocator(const allocator<_Up>&) { } |
201 | }; |
202 | |
203 | /// @} group allocator |
204 | |
205 | // Inhibit implicit instantiations for required instantiations, |
206 | // which are defined via explicit instantiations elsewhere. |
207 | #if _GLIBCXX_EXTERN_TEMPLATE |
208 | extern template class allocator<char>; |
209 | extern template class allocator<wchar_t>; |
210 | #endif |
211 | |
212 | // Undefine. |
213 | #undef __allocator_base |
214 | |
215 | // To implement Option 3 of DR 431. |
216 | template<typename _Alloc, bool = __is_empty(_Alloc)> |
217 | struct __alloc_swap |
218 | { static void _S_do_it(_Alloc&, _Alloc&) _GLIBCXX_NOEXCEPT { } }; |
219 | |
220 | template<typename _Alloc> |
221 | struct __alloc_swap<_Alloc, false> |
222 | { |
223 | static void |
224 | _S_do_it(_Alloc& __one, _Alloc& __two) _GLIBCXX_NOEXCEPT |
225 | { |
226 | // Precondition: swappable allocators. |
227 | if (__one != __two) |
228 | swap(__one, __two); |
229 | } |
230 | }; |
231 | |
232 | // Optimize for stateless allocators. |
233 | template<typename _Alloc, bool = __is_empty(_Alloc)> |
234 | struct __alloc_neq |
235 | { |
236 | static bool |
237 | _S_do_it(const _Alloc&, const _Alloc&) |
238 | { return false; } |
239 | }; |
240 | |
241 | template<typename _Alloc> |
242 | struct __alloc_neq<_Alloc, false> |
243 | { |
244 | static bool |
245 | _S_do_it(const _Alloc& __one, const _Alloc& __two) |
246 | { return __one != __two; } |
247 | }; |
248 | |
249 | #if __cplusplus >= 201103L |
250 | template<typename _Tp, bool |
251 | = __or_<is_copy_constructible<typename _Tp::value_type>, |
252 | is_nothrow_move_constructible<typename _Tp::value_type>>::value> |
253 | struct __shrink_to_fit_aux |
254 | { static bool _S_do_it(_Tp&) noexcept { return false; } }; |
255 | |
256 | template<typename _Tp> |
257 | struct __shrink_to_fit_aux<_Tp, true> |
258 | { |
259 | static bool |
260 | _S_do_it(_Tp& __c) noexcept |
261 | { |
262 | #if __cpp_exceptions |
263 | try |
264 | { |
265 | _Tp(__make_move_if_noexcept_iterator(__c.begin()), |
266 | __make_move_if_noexcept_iterator(__c.end()), |
267 | __c.get_allocator()).swap(__c); |
268 | return true; |
269 | } |
270 | catch(...) |
271 | { return false; } |
272 | #else |
273 | return false; |
274 | #endif |
275 | } |
276 | }; |
277 | #endif |
278 | |
279 | _GLIBCXX_END_NAMESPACE_VERSION |
280 | } // namespace std |
281 | |
282 | #endif |
283 | |