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1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP___MEMORY_ALLOCATOR_TRAITS_H
11#define _LIBCPP___MEMORY_ALLOCATOR_TRAITS_H
12
13#include <__config>
14#include <__cstddef/size_t.h>
15#include <__fwd/memory.h>
16#include <__memory/construct_at.h>
17#include <__memory/pointer_traits.h>
18#include <__type_traits/detected_or.h>
19#include <__type_traits/enable_if.h>
20#include <__type_traits/is_constructible.h>
21#include <__type_traits/is_empty.h>
22#include <__type_traits/is_same.h>
23#include <__type_traits/make_unsigned.h>
24#include <__type_traits/remove_reference.h>
25#include <__type_traits/void_t.h>
26#include <__utility/declval.h>
27#include <__utility/forward.h>
28#include <limits>
29
30#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
31# pragma GCC system_header
32#endif
33
34_LIBCPP_PUSH_MACROS
35#include <__undef_macros>
36
37_LIBCPP_BEGIN_NAMESPACE_STD
38
39_LIBCPP_SUPPRESS_DEPRECATED_PUSH
40// __pointer
41template <class _Tp>
42using __pointer_member _LIBCPP_NODEBUG = typename _Tp::pointer;
43
44template <class _Tp, class _Alloc>
45using __pointer _LIBCPP_NODEBUG = __detected_or_t<_Tp*, __pointer_member, __libcpp_remove_reference_t<_Alloc> >;
46
47// This trait returns _Alias<_Alloc> if that's well-formed, and _Ptr rebound to _Tp otherwise
48template <class _Alloc, template <class> class _Alias, class _Ptr, class _Tp, class = void>
49struct __rebind_or_alias_pointer {
50#ifdef _LIBCPP_CXX03_LANG
51 using type _LIBCPP_NODEBUG = typename pointer_traits<_Ptr>::template rebind<_Tp>::other;
52#else
53 using type _LIBCPP_NODEBUG = typename pointer_traits<_Ptr>::template rebind<_Tp>;
54#endif
55};
56
57template <class _Ptr, class _Alloc, class _Tp, template <class> class _Alias>
58struct __rebind_or_alias_pointer<_Alloc, _Alias, _Ptr, _Tp, __void_t<_Alias<_Alloc> > > {
59 using type _LIBCPP_NODEBUG = _Alias<_Alloc>;
60};
61
62// __const_pointer
63template <class _Alloc>
64using __const_pointer_member _LIBCPP_NODEBUG = typename _Alloc::const_pointer;
65
66template <class _Tp, class _Ptr, class _Alloc>
67using __const_pointer_t _LIBCPP_NODEBUG =
68 typename __rebind_or_alias_pointer<_Alloc, __const_pointer_member, _Ptr, const _Tp>::type;
69_LIBCPP_SUPPRESS_DEPRECATED_POP
70
71// __void_pointer
72template <class _Alloc>
73using __void_pointer_member _LIBCPP_NODEBUG = typename _Alloc::void_pointer;
74
75template <class _Ptr, class _Alloc>
76using __void_pointer_t _LIBCPP_NODEBUG =
77 typename __rebind_or_alias_pointer<_Alloc, __void_pointer_member, _Ptr, void>::type;
78
79// __const_void_pointer
80template <class _Alloc>
81using __const_void_pointer_member _LIBCPP_NODEBUG = typename _Alloc::const_void_pointer;
82
83template <class _Ptr, class _Alloc>
84using __const_void_pointer_t _LIBCPP_NODEBUG =
85 typename __rebind_or_alias_pointer<_Alloc, __const_void_pointer_member, _Ptr, const void>::type;
86
87// __size_type
88template <class _Tp>
89using __size_type_member _LIBCPP_NODEBUG = typename _Tp::size_type;
90
91template <class _Alloc, class _DiffType>
92using __size_type _LIBCPP_NODEBUG = __detected_or_t<__make_unsigned_t<_DiffType>, __size_type_member, _Alloc>;
93
94// __alloc_traits_difference_type
95template <class _Alloc, class _Ptr, class = void>
96struct __alloc_traits_difference_type {
97 using type _LIBCPP_NODEBUG = typename pointer_traits<_Ptr>::difference_type;
98};
99
100template <class _Alloc, class _Ptr>
101struct __alloc_traits_difference_type<_Alloc, _Ptr, __void_t<typename _Alloc::difference_type> > {
102 using type _LIBCPP_NODEBUG = typename _Alloc::difference_type;
103};
104
105// __propagate_on_container_copy_assignment
106template <class _Tp>
107using __propagate_on_container_copy_assignment_member _LIBCPP_NODEBUG =
108 typename _Tp::propagate_on_container_copy_assignment;
109
110template <class _Alloc>
111using __propagate_on_container_copy_assignment _LIBCPP_NODEBUG =
112 __detected_or_t<false_type, __propagate_on_container_copy_assignment_member, _Alloc>;
113
114// __propagate_on_container_move_assignment
115template <class _Tp>
116using __propagate_on_container_move_assignment_member _LIBCPP_NODEBUG =
117 typename _Tp::propagate_on_container_move_assignment;
118
119template <class _Alloc>
120using __propagate_on_container_move_assignment _LIBCPP_NODEBUG =
121 __detected_or_t<false_type, __propagate_on_container_move_assignment_member, _Alloc>;
122
123// __propagate_on_container_swap
124template <class _Tp>
125using __propagate_on_container_swap_member _LIBCPP_NODEBUG = typename _Tp::propagate_on_container_swap;
126
127template <class _Alloc>
128using __propagate_on_container_swap _LIBCPP_NODEBUG =
129 __detected_or_t<false_type, __propagate_on_container_swap_member, _Alloc>;
130
131_LIBCPP_SUPPRESS_DEPRECATED_PUSH
132// __is_always_equal
133template <class _Tp>
134using __is_always_equal_member _LIBCPP_NODEBUG = typename _Tp::is_always_equal;
135
136template <class _Alloc>
137using __is_always_equal _LIBCPP_NODEBUG =
138 __detected_or_t<typename is_empty<_Alloc>::type, __is_always_equal_member, _Alloc>;
139
140// __allocator_traits_rebind
141template <class _Tp, class _Up, class = void>
142inline const bool __has_rebind_other_v = false;
143template <class _Tp, class _Up>
144inline const bool __has_rebind_other_v<_Tp, _Up, __void_t<typename _Tp::template rebind<_Up>::other> > = true;
145
146template <class _Tp, class _Up, bool = __has_rebind_other_v<_Tp, _Up> >
147struct __allocator_traits_rebind {
148 static_assert(__has_rebind_other_v<_Tp, _Up>, "This allocator has to implement rebind");
149 using type _LIBCPP_NODEBUG = typename _Tp::template rebind<_Up>::other;
150};
151template <template <class, class...> class _Alloc, class _Tp, class... _Args, class _Up>
152struct __allocator_traits_rebind<_Alloc<_Tp, _Args...>, _Up, true> {
153 using type _LIBCPP_NODEBUG = typename _Alloc<_Tp, _Args...>::template rebind<_Up>::other;
154};
155template <template <class, class...> class _Alloc, class _Tp, class... _Args, class _Up>
156struct __allocator_traits_rebind<_Alloc<_Tp, _Args...>, _Up, false> {
157 using type _LIBCPP_NODEBUG = _Alloc<_Up, _Args...>;
158};
159_LIBCPP_SUPPRESS_DEPRECATED_POP
160
161template <class _Alloc, class _Tp>
162using __allocator_traits_rebind_t _LIBCPP_NODEBUG = typename __allocator_traits_rebind<_Alloc, _Tp>::type;
163
164_LIBCPP_SUPPRESS_DEPRECATED_PUSH
165
166// __has_allocate_hint_v
167template <class _Alloc, class _SizeType, class _ConstVoidPtr, class = void>
168inline const bool __has_allocate_hint_v = false;
169
170template <class _Alloc, class _SizeType, class _ConstVoidPtr>
171inline const bool __has_allocate_hint_v<
172 _Alloc,
173 _SizeType,
174 _ConstVoidPtr,
175 decltype((void)std::declval<_Alloc>().allocate(std::declval<_SizeType>(), std::declval<_ConstVoidPtr>()))> = true;
176
177// __has_construct_v
178template <class, class _Alloc, class... _Args>
179inline const bool __has_construct_impl = false;
180
181template <class _Alloc, class... _Args>
182inline const bool
183 __has_construct_impl<decltype((void)std::declval<_Alloc>().construct(std::declval<_Args>()...)), _Alloc, _Args...> =
184 true;
185
186template <class _Alloc, class... _Args>
187inline const bool __has_construct_v = __has_construct_impl<void, _Alloc, _Args...>;
188
189// __has_destroy_v
190template <class _Alloc, class _Pointer, class = void>
191inline const bool __has_destroy_v = false;
192
193template <class _Alloc, class _Pointer>
194inline const bool
195 __has_destroy_v<_Alloc, _Pointer, decltype((void)std::declval<_Alloc>().destroy(std::declval<_Pointer>()))> = true;
196
197// __has_max_size_v
198template <class _Alloc, class = void>
199inline const bool __has_max_size_v = false;
200
201template <class _Alloc>
202inline const bool __has_max_size_v<_Alloc, decltype((void)std::declval<_Alloc&>().max_size())> = true;
203
204// __has_select_on_container_copy_construction_v
205template <class _Alloc, class = void>
206inline const bool __has_select_on_container_copy_construction_v = false;
207
208template <class _Alloc>
209inline const bool __has_select_on_container_copy_construction_v<
210 _Alloc,
211 decltype((void)std::declval<_Alloc>().select_on_container_copy_construction())> = true;
212
213_LIBCPP_SUPPRESS_DEPRECATED_POP
214
215#if _LIBCPP_STD_VER >= 23
216
217template <class _Pointer, class _SizeType = size_t>
218struct allocation_result {
219 _Pointer ptr;
220 _SizeType count;
221};
222_LIBCPP_CTAD_SUPPORTED_FOR_TYPE(allocation_result);
223
224#endif // _LIBCPP_STD_VER
225
226template <class _Alloc>
227struct allocator_traits {
228 using allocator_type = _Alloc;
229 using value_type = typename allocator_type::value_type;
230 using pointer = __pointer<value_type, allocator_type>;
231 using const_pointer = __const_pointer_t<value_type, pointer, allocator_type>;
232 using void_pointer = __void_pointer_t<pointer, allocator_type>;
233 using const_void_pointer = __const_void_pointer_t<pointer, allocator_type>;
234 using difference_type = typename __alloc_traits_difference_type<allocator_type, pointer>::type;
235 using size_type = __size_type<allocator_type, difference_type>;
236 using propagate_on_container_copy_assignment = __propagate_on_container_copy_assignment<allocator_type>;
237 using propagate_on_container_move_assignment = __propagate_on_container_move_assignment<allocator_type>;
238 using propagate_on_container_swap = __propagate_on_container_swap<allocator_type>;
239 using is_always_equal = __is_always_equal<allocator_type>;
240
241#ifndef _LIBCPP_CXX03_LANG
242 template <class _Tp>
243 using rebind_alloc = __allocator_traits_rebind_t<allocator_type, _Tp>;
244 template <class _Tp>
245 using rebind_traits = allocator_traits<rebind_alloc<_Tp> >;
246#else // _LIBCPP_CXX03_LANG
247 template <class _Tp>
248 struct rebind_alloc {
249 using other = __allocator_traits_rebind_t<allocator_type, _Tp>;
250 };
251 template <class _Tp>
252 struct rebind_traits {
253 using other = allocator_traits<typename rebind_alloc<_Tp>::other>;
254 };
255#endif // _LIBCPP_CXX03_LANG
256
257 [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static pointer
258 allocate(allocator_type& __a, size_type __n) {
259 return __a.allocate(__n);
260 }
261
262 template <class _Ap = _Alloc, __enable_if_t<__has_allocate_hint_v<_Ap, size_type, const_void_pointer>, int> = 0>
263 [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static pointer
264 allocate(allocator_type& __a, size_type __n, const_void_pointer __hint) {
265 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
266 return __a.allocate(__n, __hint);
267 _LIBCPP_SUPPRESS_DEPRECATED_POP
268 }
269 template <class _Ap = _Alloc, __enable_if_t<!__has_allocate_hint_v<_Ap, size_type, const_void_pointer>, int> = 0>
270 [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static pointer
271 allocate(allocator_type& __a, size_type __n, const_void_pointer) {
272 return __a.allocate(__n);
273 }
274
275#if _LIBCPP_STD_VER >= 23
276 template <class _Ap = _Alloc>
277 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI static constexpr allocation_result<pointer, size_type>
278 allocate_at_least(_Ap& __alloc, size_type __n) {
279 if constexpr (requires { __alloc.allocate_at_least(__n); }) {
280 return __alloc.allocate_at_least(__n);
281 } else {
282 return {__alloc.allocate(__n), __n};
283 }
284 }
285#endif
286
287 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static void
288 deallocate(allocator_type& __a, pointer __p, size_type __n) _NOEXCEPT {
289 __a.deallocate(__p, __n);
290 }
291
292 template <class _Tp, class... _Args, __enable_if_t<__has_construct_v<allocator_type, _Tp*, _Args...>, int> = 0>
293 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static void
294 construct(allocator_type& __a, _Tp* __p, _Args&&... __args) {
295 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
296 __a.construct(__p, std::forward<_Args>(__args)...);
297 _LIBCPP_SUPPRESS_DEPRECATED_POP
298 }
299 template <class _Tp, class... _Args, __enable_if_t<!__has_construct_v<allocator_type, _Tp*, _Args...>, int> = 0>
300 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static void
301 construct(allocator_type&, _Tp* __p, _Args&&... __args) {
302 std::__construct_at(__p, std::forward<_Args>(__args)...);
303 }
304
305 template <class _Tp, __enable_if_t<__has_destroy_v<allocator_type, _Tp*>, int> = 0>
306 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static void destroy(allocator_type& __a, _Tp* __p) {
307 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
308 __a.destroy(__p);
309 _LIBCPP_SUPPRESS_DEPRECATED_POP
310 }
311 template <class _Tp, __enable_if_t<!__has_destroy_v<allocator_type, _Tp*>, int> = 0>
312 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static void destroy(allocator_type&, _Tp* __p) {
313 std::__destroy_at(__p);
314 }
315
316 template <class _Ap = _Alloc, __enable_if_t<__has_max_size_v<const _Ap>, int> = 0>
317 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static size_type max_size(const allocator_type& __a) _NOEXCEPT {
318 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
319 return __a.max_size();
320 _LIBCPP_SUPPRESS_DEPRECATED_POP
321 }
322 template <class _Ap = _Alloc, __enable_if_t<!__has_max_size_v<const _Ap>, int> = 0>
323 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static size_type max_size(const allocator_type&) _NOEXCEPT {
324 return numeric_limits<size_type>::max() / sizeof(value_type);
325 }
326
327 template <class _Ap = _Alloc, __enable_if_t<__has_select_on_container_copy_construction_v<const _Ap>, int> = 0>
328 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static allocator_type
329 select_on_container_copy_construction(const allocator_type& __a) {
330 return __a.select_on_container_copy_construction();
331 }
332 template <class _Ap = _Alloc, __enable_if_t<!__has_select_on_container_copy_construction_v<const _Ap>, int> = 0>
333 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static allocator_type
334 select_on_container_copy_construction(const allocator_type& __a) {
335 return __a;
336 }
337};
338
339#ifndef _LIBCPP_CXX03_LANG
340template <class _Traits, class _Tp>
341using __rebind_alloc _LIBCPP_NODEBUG = typename _Traits::template rebind_alloc<_Tp>;
342#else
343template <class _Traits, class _Tp>
344using __rebind_alloc _LIBCPP_NODEBUG = typename _Traits::template rebind_alloc<_Tp>::other;
345#endif
346
347template <class _Alloc>
348struct __check_valid_allocator : true_type {
349 using _Traits _LIBCPP_NODEBUG = std::allocator_traits<_Alloc>;
350 static_assert(is_same<_Alloc, __rebind_alloc<_Traits, typename _Traits::value_type> >::value,
351 "[allocator.requirements] states that rebinding an allocator to the same type should result in the "
352 "original allocator");
353};
354
355// __is_default_allocator_v
356template <class _Tp>
357inline const bool __is_std_allocator_v = false;
358
359template <class _Tp>
360inline const bool __is_std_allocator_v<allocator<_Tp> > = true;
361
362// __is_cpp17_move_insertable_v
363template <class _Alloc>
364inline const bool __is_cpp17_move_insertable_v =
365 is_move_constructible<typename _Alloc::value_type>::value ||
366 (!__is_std_allocator_v<_Alloc> &&
367 __has_construct_v<_Alloc, typename _Alloc::value_type*, typename _Alloc::value_type&&>);
368
369// __is_cpp17_copy_insertable_v
370template <class _Alloc>
371inline const bool __is_cpp17_copy_insertable_v =
372 __is_cpp17_move_insertable_v<_Alloc> &&
373 (is_copy_constructible<typename _Alloc::value_type>::value ||
374 (!__is_std_allocator_v<_Alloc> &&
375 __has_construct_v<_Alloc, typename _Alloc::value_type*, const typename _Alloc::value_type&>));
376
377_LIBCPP_END_NAMESPACE_STD
378
379_LIBCPP_POP_MACROS
380
381#endif // _LIBCPP___MEMORY_ALLOCATOR_TRAITS_H
382

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source code of libcxx/include/__memory/allocator_traits.h