libstdc++
scoped_allocator
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1// <scoped_allocator> -*- C++ -*-
2
3// Copyright (C) 2011-2024 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/scoped_allocator
26 * This is a Standard C++ Library header.
27 */
28
29#ifndef _SCOPED_ALLOCATOR
30#define _SCOPED_ALLOCATOR 1
31
32#pragma GCC system_header
33
34#if __cplusplus < 201103L
35# include <bits/c++0x_warning.h>
36#else
37
38#include <tuple>
39#include <bits/alloc_traits.h>
40#include <bits/stl_pair.h>
41#include <bits/uses_allocator.h>
42#if __cplusplus > 201703L
43# include <bits/uses_allocator_args.h>
44#endif
45
46#define __glibcxx_want_allocator_traits_is_always_equal
47#include <bits/version.h>
48
49namespace std _GLIBCXX_VISIBILITY(default)
50{
51_GLIBCXX_BEGIN_NAMESPACE_VERSION
52
53 /**
54 * @addtogroup allocators
55 * @{
56 */
57
58 template<typename _OuterAlloc, typename... _InnerAllocs>
59 class scoped_allocator_adaptor;
60
61 /// @cond undocumented
62
63 template<typename _Alloc>
64 using __outer_allocator_t
65 = decltype(std::declval<_Alloc>().outer_allocator());
66
67 template<typename _Alloc, typename = void>
68 struct __outermost_type
69 {
70 using type = _Alloc;
71 static type& _S_outermost(_Alloc& __a) noexcept { return __a; }
72 };
73
74 template<typename _Alloc>
75 struct __outermost_type<_Alloc, __void_t<__outer_allocator_t<_Alloc>>>
76 : __outermost_type<
77 typename remove_reference<__outer_allocator_t<_Alloc>>::type
78 >
79 {
80 using __base = __outermost_type<
81 typename remove_reference<__outer_allocator_t<_Alloc>>::type
82 >;
83
84 static typename __base::type&
85 _S_outermost(_Alloc& __a) noexcept
86 { return __base::_S_outermost(__a.outer_allocator()); }
87 };
88
89 // Implementation of the OUTERMOST pseudofunction
90 template<typename _Alloc>
91 inline typename __outermost_type<_Alloc>::type&
92 __outermost(_Alloc& __a)
93 { return __outermost_type<_Alloc>::_S_outermost(__a); }
94
95 template<typename...>
96 struct __inner_type_impl;
97
98 template<typename _Outer>
99 struct __inner_type_impl<_Outer>
100 {
101 typedef scoped_allocator_adaptor<_Outer> __type;
102
103 __inner_type_impl() = default;
104 __inner_type_impl(const __inner_type_impl&) = default;
105 __inner_type_impl(__inner_type_impl&&) = default;
106 __inner_type_impl& operator=(const __inner_type_impl&) = default;
107 __inner_type_impl& operator=(__inner_type_impl&&) = default;
108
109 template<typename _Alloc>
110 __inner_type_impl(const __inner_type_impl<_Alloc>&) noexcept
111 { }
112
113 template<typename _Alloc>
114 __inner_type_impl(__inner_type_impl<_Alloc>&&) noexcept
115 { }
116
117 __type&
118 _M_get(__type* __p) noexcept { return *__p; }
119
120 const __type&
121 _M_get(const __type* __p) const noexcept { return *__p; }
122
123 tuple<>
124 _M_tie() const noexcept { return tuple<>(); }
125
126 bool
127 operator==(const __inner_type_impl&) const noexcept
128 { return true; }
129 };
130
131 template<typename _Outer, typename _InnerHead, typename... _InnerTail>
132 struct __inner_type_impl<_Outer, _InnerHead, _InnerTail...>
133 {
134 typedef scoped_allocator_adaptor<_InnerHead, _InnerTail...> __type;
135
136 __inner_type_impl() = default;
137 __inner_type_impl(const __inner_type_impl&) = default;
138 __inner_type_impl(__inner_type_impl&&) = default;
139 __inner_type_impl& operator=(const __inner_type_impl&) = default;
140 __inner_type_impl& operator=(__inner_type_impl&&) = default;
141
142 template<typename... _Allocs>
143 __inner_type_impl(const __inner_type_impl<_Allocs...>& __other) noexcept
144 : _M_inner(__other._M_inner) { }
145
146 template<typename... _Allocs>
147 __inner_type_impl(__inner_type_impl<_Allocs...>&& __other) noexcept
148 : _M_inner(std::move(__other._M_inner)) { }
149
150 template<typename... _Args>
151 explicit
152 __inner_type_impl(_Args&&... __args) noexcept
153 : _M_inner(std::forward<_Args>(__args)...) { }
154
155 __type&
156 _M_get(void*) noexcept { return _M_inner; }
157
158 const __type&
159 _M_get(const void*) const noexcept { return _M_inner; }
160
161 tuple<const _InnerHead&, const _InnerTail&...>
162 _M_tie() const noexcept
163 { return _M_inner._M_tie(); }
164
165 bool
166 operator==(const __inner_type_impl& __other) const noexcept
167 { return _M_inner == __other._M_inner; }
168
169 private:
170 template<typename...> friend struct __inner_type_impl;
171 template<typename, typename...> friend class scoped_allocator_adaptor;
172
173 __type _M_inner;
174 };
175
176 /// @endcond
177
178 /// An adaptor to recursively pass an allocator to the objects it constructs
179 template<typename _OuterAlloc, typename... _InnerAllocs>
180 class scoped_allocator_adaptor
181 : public _OuterAlloc
182 {
183 typedef allocator_traits<_OuterAlloc> __traits;
184
185 typedef __inner_type_impl<_OuterAlloc, _InnerAllocs...> __inner_type;
186 __inner_type _M_inner;
187
188 template<typename _Outer, typename... _Inner>
189 friend class scoped_allocator_adaptor;
190
191 template<typename...>
192 friend struct __inner_type_impl;
193
194 tuple<const _OuterAlloc&, const _InnerAllocs&...>
195 _M_tie() const noexcept
196 { return std::tuple_cat(std::tie(outer_allocator()), _M_inner._M_tie()); }
197
198 template<typename _Alloc>
199 using __outermost_alloc_traits
200 = allocator_traits<typename __outermost_type<_Alloc>::type>;
201
202#if ! __glibcxx_make_obj_using_allocator
203 template<typename _Tp, typename... _Args>
204 void
205 _M_construct(__uses_alloc0, _Tp* __p, _Args&&... __args)
206 {
207 typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
208 _O_traits::construct(__outermost(*this), __p,
209 std::forward<_Args>(__args)...);
210 }
211
212 typedef __uses_alloc1<typename __inner_type::__type> __uses_alloc1_;
213 typedef __uses_alloc2<typename __inner_type::__type> __uses_alloc2_;
214
215 template<typename _Tp, typename... _Args>
216 void
217 _M_construct(__uses_alloc1_, _Tp* __p, _Args&&... __args)
218 {
219 typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
220 _O_traits::construct(__outermost(*this), __p,
221 allocator_arg, inner_allocator(),
222 std::forward<_Args>(__args)...);
223 }
224
225 template<typename _Tp, typename... _Args>
226 void
227 _M_construct(__uses_alloc2_, _Tp* __p, _Args&&... __args)
228 {
229 typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
230 _O_traits::construct(__outermost(*this), __p,
231 std::forward<_Args>(__args)...,
232 inner_allocator());
233 }
234#endif // ! make_obj_using_allocator
235
236 template<typename _Alloc>
237 static _Alloc
238 _S_select_on_copy(const _Alloc& __a)
239 {
240 typedef allocator_traits<_Alloc> __a_traits;
241 return __a_traits::select_on_container_copy_construction(__a);
242 }
243
244 template<std::size_t... _Indices>
245 scoped_allocator_adaptor(tuple<const _OuterAlloc&,
246 const _InnerAllocs&...> __refs,
247 _Index_tuple<_Indices...>)
248 : _OuterAlloc(_S_select_on_copy(std::get<0>(__refs))),
249 _M_inner(_S_select_on_copy(std::get<_Indices+1>(__refs))...)
250 { }
251
252 // Used to constrain constructors to disallow invalid conversions.
253 template<typename _Alloc>
254 using _Constructible = typename enable_if<
255 is_constructible<_OuterAlloc, _Alloc>::value
256 >::type;
257
258 // _GLIBCXX_RESOLVE_LIB_DEFECTS
259 // 2975. Missing case for pair construction in scoped [...] allocators
260 template<typename _Tp>
261 struct __not_pair { using type = void; };
262
263 template<typename _Tp, typename _Up>
264 struct __not_pair<pair<_Tp, _Up>> { };
265
266 public:
267 typedef _OuterAlloc outer_allocator_type;
268 typedef typename __inner_type::__type inner_allocator_type;
269
270 typedef typename __traits::value_type value_type;
271 typedef typename __traits::size_type size_type;
272 typedef typename __traits::difference_type difference_type;
273 typedef typename __traits::pointer pointer;
274 typedef typename __traits::const_pointer const_pointer;
275 typedef typename __traits::void_pointer void_pointer;
276 typedef typename __traits::const_void_pointer const_void_pointer;
277
278 typedef typename __or_<
279 typename __traits::propagate_on_container_copy_assignment,
280 typename allocator_traits<_InnerAllocs>::
281 propagate_on_container_copy_assignment...>::type
282 propagate_on_container_copy_assignment;
283
284 typedef typename __or_<
285 typename __traits::propagate_on_container_move_assignment,
286 typename allocator_traits<_InnerAllocs>::
287 propagate_on_container_move_assignment...>::type
288 propagate_on_container_move_assignment;
289
290 typedef typename __or_<
291 typename __traits::propagate_on_container_swap,
292 typename allocator_traits<_InnerAllocs>::
293 propagate_on_container_swap...>::type
294 propagate_on_container_swap;
295
296 typedef typename __and_<
297 typename __traits::is_always_equal,
298 typename allocator_traits<_InnerAllocs>::is_always_equal...>::type
299 is_always_equal;
300
301 template <class _Tp>
302 struct rebind
303 {
304 typedef scoped_allocator_adaptor<
305 typename __traits::template rebind_alloc<_Tp>,
306 _InnerAllocs...> other;
307 };
308
309 scoped_allocator_adaptor() : _OuterAlloc(), _M_inner() { }
310
311 template<typename _Outer2, typename = _Constructible<_Outer2>>
312 scoped_allocator_adaptor(_Outer2&& __outer,
313 const _InnerAllocs&... __inner) noexcept
314 : _OuterAlloc(std::forward<_Outer2>(__outer)),
315 _M_inner(__inner...)
316 { }
317
318 scoped_allocator_adaptor(const scoped_allocator_adaptor& __other) noexcept
319 : _OuterAlloc(__other.outer_allocator()),
320 _M_inner(__other._M_inner)
321 { }
322
323 scoped_allocator_adaptor(scoped_allocator_adaptor&& __other) noexcept
324 : _OuterAlloc(std::move(__other.outer_allocator())),
325 _M_inner(std::move(__other._M_inner))
326 { }
327
328 template<typename _Outer2, typename = _Constructible<const _Outer2&>>
329 scoped_allocator_adaptor(
330 const scoped_allocator_adaptor<_Outer2, _InnerAllocs...>& __other
331 ) noexcept
332 : _OuterAlloc(__other.outer_allocator()),
333 _M_inner(__other._M_inner)
334 { }
335
336 template<typename _Outer2, typename = _Constructible<_Outer2>>
337 scoped_allocator_adaptor(
338 scoped_allocator_adaptor<_Outer2, _InnerAllocs...>&& __other) noexcept
339 : _OuterAlloc(std::move(__other.outer_allocator())),
340 _M_inner(std::move(__other._M_inner))
341 { }
342
343 scoped_allocator_adaptor&
344 operator=(const scoped_allocator_adaptor&) = default;
345
346 scoped_allocator_adaptor&
347 operator=(scoped_allocator_adaptor&&) = default;
348
349 inner_allocator_type&
350 inner_allocator() noexcept
351 { return _M_inner._M_get(this); }
352
353 const inner_allocator_type&
354 inner_allocator() const noexcept
355 { return _M_inner._M_get(this); }
356
357 outer_allocator_type&
358 outer_allocator() noexcept
359 { return static_cast<_OuterAlloc&>(*this); }
360
361 const outer_allocator_type&
362 outer_allocator() const noexcept
363 { return static_cast<const _OuterAlloc&>(*this); }
364
365 _GLIBCXX_NODISCARD pointer
366 allocate(size_type __n)
367 { return __traits::allocate(outer_allocator(), __n); }
368
369 _GLIBCXX_NODISCARD pointer
370 allocate(size_type __n, const_void_pointer __hint)
371 { return __traits::allocate(outer_allocator(), __n, __hint); }
372
373 void deallocate(pointer __p, size_type __n) noexcept
374 { return __traits::deallocate(outer_allocator(), __p, __n); }
375
376 size_type max_size() const
377 { return __traits::max_size(outer_allocator()); }
378
379#if ! __glibcxx_make_obj_using_allocator
380 template<typename _Tp, typename... _Args>
381 typename __not_pair<_Tp>::type
382 construct(_Tp* __p, _Args&&... __args)
383 {
384 auto& __inner = inner_allocator();
385 auto __use_tag
386 = std::__use_alloc<_Tp, inner_allocator_type, _Args...>(__inner);
387 _M_construct(__use_tag, __p, std::forward<_Args>(__args)...);
388 }
389
390 template<typename _T1, typename _T2, typename... _Args1,
391 typename... _Args2>
392 void
393 construct(pair<_T1, _T2>* __p, piecewise_construct_t,
394 tuple<_Args1...> __x, tuple<_Args2...> __y)
395 {
396 // _GLIBCXX_RESOLVE_LIB_DEFECTS
397 // 2203. wrong argument types for piecewise construction
398 auto& __inner = inner_allocator();
399 auto __x_use_tag
400 = std::__use_alloc<_T1, inner_allocator_type, _Args1...>(__inner);
401 auto __y_use_tag
402 = std::__use_alloc<_T2, inner_allocator_type, _Args2...>(__inner);
403 typename _Build_index_tuple<sizeof...(_Args1)>::__type __x_indices;
404 typename _Build_index_tuple<sizeof...(_Args2)>::__type __y_indices;
405 typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
406 _O_traits::construct(__outermost(*this), __p, piecewise_construct,
407 _M_construct_p(__x_use_tag, __x_indices, __x),
408 _M_construct_p(__y_use_tag, __y_indices, __y));
409 }
410
411 template<typename _T1, typename _T2>
412 void
413 construct(pair<_T1, _T2>* __p)
414 { construct(__p, piecewise_construct, tuple<>(), tuple<>()); }
415
416 template<typename _T1, typename _T2, typename _Up, typename _Vp>
417 void
418 construct(pair<_T1, _T2>* __p, _Up&& __u, _Vp&& __v)
419 {
420 construct(__p, piecewise_construct,
421 std::forward_as_tuple(std::forward<_Up>(__u)),
422 std::forward_as_tuple(std::forward<_Vp>(__v)));
423 }
424
425 template<typename _T1, typename _T2, typename _Up, typename _Vp>
426 void
427 construct(pair<_T1, _T2>* __p, const pair<_Up, _Vp>& __x)
428 {
429 construct(__p, piecewise_construct,
430 std::forward_as_tuple(__x.first),
431 std::forward_as_tuple(__x.second));
432 }
433
434 template<typename _T1, typename _T2, typename _Up, typename _Vp>
435 void
436 construct(pair<_T1, _T2>* __p, pair<_Up, _Vp>&& __x)
437 {
438 construct(__p, piecewise_construct,
439 std::forward_as_tuple(std::forward<_Up>(__x.first)),
440 std::forward_as_tuple(std::forward<_Vp>(__x.second)));
441 }
442#else // make_obj_using_allocator
443 template<typename _Tp, typename... _Args>
444 __attribute__((__nonnull__))
445 void
446 construct(_Tp* __p, _Args&&... __args)
447 {
448 typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
449 std::apply([__p, this](auto&&... __newargs) {
450 _O_traits::construct(__outermost(*this), __p,
451 std::forward<decltype(__newargs)>(__newargs)...);
452 },
453 uses_allocator_construction_args<_Tp>(inner_allocator(),
454 std::forward<_Args>(__args)...));
455 }
456#endif
457
458 template<typename _Tp>
459 void destroy(_Tp* __p)
460 {
461 typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
462 _O_traits::destroy(__outermost(*this), __p);
463 }
464
465 scoped_allocator_adaptor
466 select_on_container_copy_construction() const
467 {
468 typedef typename _Build_index_tuple<sizeof...(_InnerAllocs)>::__type
469 _Indices;
470 return scoped_allocator_adaptor(_M_tie(), _Indices());
471 }
472
473 template <typename _OutA1, typename _OutA2, typename... _InA>
474 friend bool
475 operator==(const scoped_allocator_adaptor<_OutA1, _InA...>& __a,
476 const scoped_allocator_adaptor<_OutA2, _InA...>& __b) noexcept;
477
478 private:
479#if ! __glibcxx_make_obj_using_allocator
480 template<typename _Ind, typename... _Args>
481 tuple<_Args&&...>
482 _M_construct_p(__uses_alloc0, _Ind, tuple<_Args...>& __t)
483 { return std::move(__t); }
484
485 template<size_t... _Ind, typename... _Args>
486 tuple<allocator_arg_t, inner_allocator_type&, _Args&&...>
487 _M_construct_p(__uses_alloc1_, _Index_tuple<_Ind...>,
488 tuple<_Args...>& __t)
489 {
490 return { allocator_arg, inner_allocator(),
491 std::get<_Ind>(std::move(__t))...
492 };
493 }
494
495 template<size_t... _Ind, typename... _Args>
496 tuple<_Args&&..., inner_allocator_type&>
497 _M_construct_p(__uses_alloc2_, _Index_tuple<_Ind...>,
498 tuple<_Args...>& __t)
499 {
500 return { std::get<_Ind>(std::move(__t))..., inner_allocator() };
501 }
502#endif // ! make_obj_using_allocator
503 };
504
505 /// @related std::scoped_allocator_adaptor
506 template <typename _OutA1, typename _OutA2, typename... _InA>
507 inline bool
508 operator==(const scoped_allocator_adaptor<_OutA1, _InA...>& __a,
509 const scoped_allocator_adaptor<_OutA2, _InA...>& __b) noexcept
510 {
511 return __a.outer_allocator() == __b.outer_allocator()
512 && __a._M_inner == __b._M_inner;
513 }
514
515#if __cpp_impl_three_way_comparison < 201907L
516 /// @related std::scoped_allocator_adaptor
517 template <typename _OutA1, typename _OutA2, typename... _InA>
518 inline bool
519 operator!=(const scoped_allocator_adaptor<_OutA1, _InA...>& __a,
520 const scoped_allocator_adaptor<_OutA2, _InA...>& __b) noexcept
521 { return !(__a == __b); }
522#endif
523
524 /// @}
525
526_GLIBCXX_END_NAMESPACE_VERSION
527} // namespace
528
529#endif // C++11
530
531#endif // _SCOPED_ALLOCATOR