1// <scoped_allocator> -*- C++ -*-
2
3// Copyright (C) 2011-2021 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/scoped_allocator
26 * This is a Standard C++ Library header.
27 * @ingroup allocators
28 */
29
30#ifndef _SCOPED_ALLOCATOR
31#define _SCOPED_ALLOCATOR 1
32
33#pragma GCC system_header
34
35#if __cplusplus < 201103L
36# include <bits/c++0x_warning.h>
37#else
38
39#include <tuple>
40#include <bits/alloc_traits.h>
41#include <bits/stl_pair.h>
42#include <bits/uses_allocator.h>
43#if __cplusplus > 201703L
44# include <bits/uses_allocator_args.h>
45#endif
46
47namespace std _GLIBCXX_VISIBILITY(default)
48{
49_GLIBCXX_BEGIN_NAMESPACE_VERSION
50
51 /**
52 * @addtogroup allocators
53 * @{
54 */
55
56 template<typename _OuterAlloc, typename... _InnerAllocs>
57 class scoped_allocator_adaptor;
58
59 /// @cond undocumented
60
61 template<typename _Alloc>
62 using __outer_allocator_t
63 = decltype(std::declval<_Alloc>().outer_allocator());
64
65 template<typename _Alloc, typename = void>
66 struct __outermost_type
67 {
68 using type = _Alloc;
69 static type& _S_outermost(_Alloc& __a) { return __a; }
70 };
71
72 template<typename _Alloc>
73 struct __outermost_type<_Alloc, __void_t<__outer_allocator_t<_Alloc>>>
74 : __outermost_type<
75 typename remove_reference<__outer_allocator_t<_Alloc>>::type
76 >
77 {
78 using __base = __outermost_type<
79 typename remove_reference<__outer_allocator_t<_Alloc>>::type
80 >;
81
82 static typename __base::type&
83 _S_outermost(_Alloc& __a)
84 { return __base::_S_outermost(__a.outer_allocator()); }
85 };
86
87 // Implementation of the OUTERMOST pseudofunction
88 template<typename _Alloc>
89 inline typename __outermost_type<_Alloc>::type&
90 __outermost(_Alloc& __a)
91 { return __outermost_type<_Alloc>::_S_outermost(__a); }
92
93 template<typename...>
94 struct __inner_type_impl;
95
96 template<typename _Outer>
97 struct __inner_type_impl<_Outer>
98 {
99 typedef scoped_allocator_adaptor<_Outer> __type;
100
101 __inner_type_impl() = default;
102 __inner_type_impl(const __inner_type_impl&) = default;
103 __inner_type_impl(__inner_type_impl&&) = default;
104 __inner_type_impl& operator=(const __inner_type_impl&) = default;
105 __inner_type_impl& operator=(__inner_type_impl&&) = default;
106
107 template<typename _Alloc>
108 __inner_type_impl(const __inner_type_impl<_Alloc>& __other)
109 { }
110
111 template<typename _Alloc>
112 __inner_type_impl(__inner_type_impl<_Alloc>&& __other)
113 { }
114
115 __type&
116 _M_get(__type* __p) noexcept { return *__p; }
117
118 const __type&
119 _M_get(const __type* __p) const noexcept { return *__p; }
120
121 tuple<>
122 _M_tie() const noexcept { return tuple<>(); }
123
124 bool
125 operator==(const __inner_type_impl&) const noexcept
126 { return true; }
127 };
128
129 template<typename _Outer, typename _InnerHead, typename... _InnerTail>
130 struct __inner_type_impl<_Outer, _InnerHead, _InnerTail...>
131 {
132 typedef scoped_allocator_adaptor<_InnerHead, _InnerTail...> __type;
133
134 __inner_type_impl() = default;
135 __inner_type_impl(const __inner_type_impl&) = default;
136 __inner_type_impl(__inner_type_impl&&) = default;
137 __inner_type_impl& operator=(const __inner_type_impl&) = default;
138 __inner_type_impl& operator=(__inner_type_impl&&) = default;
139
140 template<typename... _Allocs>
141 __inner_type_impl(const __inner_type_impl<_Allocs...>& __other)
142 : _M_inner(__other._M_inner) { }
143
144 template<typename... _Allocs>
145 __inner_type_impl(__inner_type_impl<_Allocs...>&& __other)
146 : _M_inner(std::move(__other._M_inner)) { }
147
148 template<typename... _Args>
149 explicit
150 __inner_type_impl(_Args&&... __args)
151 : _M_inner(std::forward<_Args>(__args)...) { }
152
153 __type&
154 _M_get(void*) noexcept { return _M_inner; }
155
156 const __type&
157 _M_get(const void*) const noexcept { return _M_inner; }
158
159 tuple<const _InnerHead&, const _InnerTail&...>
160 _M_tie() const noexcept
161 { return _M_inner._M_tie(); }
162
163 bool
164 operator==(const __inner_type_impl& __other) const noexcept
165 { return _M_inner == __other._M_inner; }
166
167 private:
168 template<typename...> friend class __inner_type_impl;
169 template<typename, typename...> friend class scoped_allocator_adaptor;
170
171 __type _M_inner;
172 };
173
174 /// @endcond
175
176 /// An adaptor to recursively pass an allocator to the objects it constructs
177 template<typename _OuterAlloc, typename... _InnerAllocs>
178 class scoped_allocator_adaptor
179 : public _OuterAlloc
180 {
181 typedef allocator_traits<_OuterAlloc> __traits;
182
183 typedef __inner_type_impl<_OuterAlloc, _InnerAllocs...> __inner_type;
184 __inner_type _M_inner;
185
186 template<typename _Outer, typename... _Inner>
187 friend class scoped_allocator_adaptor;
188
189 template<typename...>
190 friend class __inner_type_impl;
191
192 tuple<const _OuterAlloc&, const _InnerAllocs&...>
193 _M_tie() const noexcept
194 { return std::tuple_cat(std::tie(outer_allocator()), _M_inner._M_tie()); }
195
196 template<typename _Alloc>
197 using __outermost_alloc_traits
198 = allocator_traits<typename __outermost_type<_Alloc>::type>;
199
200#if ! __cpp_lib_make_obj_using_allocator
201 template<typename _Tp, typename... _Args>
202 void
203 _M_construct(__uses_alloc0, _Tp* __p, _Args&&... __args)
204 {
205 typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
206 _O_traits::construct(__outermost(*this), __p,
207 std::forward<_Args>(__args)...);
208 }
209
210 typedef __uses_alloc1<typename __inner_type::__type> __uses_alloc1_;
211 typedef __uses_alloc2<typename __inner_type::__type> __uses_alloc2_;
212
213 template<typename _Tp, typename... _Args>
214 void
215 _M_construct(__uses_alloc1_, _Tp* __p, _Args&&... __args)
216 {
217 typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
218 _O_traits::construct(__outermost(*this), __p,
219 allocator_arg, inner_allocator(),
220 std::forward<_Args>(__args)...);
221 }
222
223 template<typename _Tp, typename... _Args>
224 void
225 _M_construct(__uses_alloc2_, _Tp* __p, _Args&&... __args)
226 {
227 typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
228 _O_traits::construct(__outermost(*this), __p,
229 std::forward<_Args>(__args)...,
230 inner_allocator());
231 }
232#endif // ! make_obj_using_allocator
233
234 template<typename _Alloc>
235 static _Alloc
236 _S_select_on_copy(const _Alloc& __a)
237 {
238 typedef allocator_traits<_Alloc> __a_traits;
239 return __a_traits::select_on_container_copy_construction(__a);
240 }
241
242 template<std::size_t... _Indices>
243 scoped_allocator_adaptor(tuple<const _OuterAlloc&,
244 const _InnerAllocs&...> __refs,
245 _Index_tuple<_Indices...>)
246 : _OuterAlloc(_S_select_on_copy(std::get<0>(__refs))),
247 _M_inner(_S_select_on_copy(std::get<_Indices+1>(__refs))...)
248 { }
249
250 // Used to constrain constructors to disallow invalid conversions.
251 template<typename _Alloc>
252 using _Constructible = typename enable_if<
253 is_constructible<_OuterAlloc, _Alloc>::value
254 >::type;
255
256 // _GLIBCXX_RESOLVE_LIB_DEFECTS
257 // 2975. Missing case for pair construction in scoped [...] allocators
258 template<typename _Tp>
259 struct __not_pair { using type = void; };
260
261 template<typename _Tp, typename _Up>
262 struct __not_pair<pair<_Tp, _Up>> { };
263
264 public:
265 typedef _OuterAlloc outer_allocator_type;
266 typedef typename __inner_type::__type inner_allocator_type;
267
268 typedef typename __traits::value_type value_type;
269 typedef typename __traits::size_type size_type;
270 typedef typename __traits::difference_type difference_type;
271 typedef typename __traits::pointer pointer;
272 typedef typename __traits::const_pointer const_pointer;
273 typedef typename __traits::void_pointer void_pointer;
274 typedef typename __traits::const_void_pointer const_void_pointer;
275
276 typedef typename __or_<
277 typename __traits::propagate_on_container_copy_assignment,
278 typename allocator_traits<_InnerAllocs>::
279 propagate_on_container_copy_assignment...>::type
280 propagate_on_container_copy_assignment;
281
282 typedef typename __or_<
283 typename __traits::propagate_on_container_move_assignment,
284 typename allocator_traits<_InnerAllocs>::
285 propagate_on_container_move_assignment...>::type
286 propagate_on_container_move_assignment;
287
288 typedef typename __or_<
289 typename __traits::propagate_on_container_swap,
290 typename allocator_traits<_InnerAllocs>::
291 propagate_on_container_swap...>::type
292 propagate_on_container_swap;
293
294 typedef typename __and_<
295 typename __traits::is_always_equal,
296 typename allocator_traits<_InnerAllocs>::is_always_equal...>::type
297 is_always_equal;
298
299 template <class _Tp>
300 struct rebind
301 {
302 typedef scoped_allocator_adaptor<
303 typename __traits::template rebind_alloc<_Tp>,
304 _InnerAllocs...> other;
305 };
306
307 scoped_allocator_adaptor() : _OuterAlloc(), _M_inner() { }
308
309 template<typename _Outer2, typename = _Constructible<_Outer2>>
310 scoped_allocator_adaptor(_Outer2&& __outer,
311 const _InnerAllocs&... __inner)
312 : _OuterAlloc(std::forward<_Outer2>(__outer)),
313 _M_inner(__inner...)
314 { }
315
316 scoped_allocator_adaptor(const scoped_allocator_adaptor& __other)
317 : _OuterAlloc(__other.outer_allocator()),
318 _M_inner(__other._M_inner)
319 { }
320
321 scoped_allocator_adaptor(scoped_allocator_adaptor&& __other)
322 : _OuterAlloc(std::move(__other.outer_allocator())),
323 _M_inner(std::move(__other._M_inner))
324 { }
325
326 template<typename _Outer2, typename = _Constructible<const _Outer2&>>
327 scoped_allocator_adaptor(
328 const scoped_allocator_adaptor<_Outer2, _InnerAllocs...>& __other)
329 : _OuterAlloc(__other.outer_allocator()),
330 _M_inner(__other._M_inner)
331 { }
332
333 template<typename _Outer2, typename = _Constructible<_Outer2>>
334 scoped_allocator_adaptor(
335 scoped_allocator_adaptor<_Outer2, _InnerAllocs...>&& __other)
336 : _OuterAlloc(std::move(__other.outer_allocator())),
337 _M_inner(std::move(__other._M_inner))
338 { }
339
340 scoped_allocator_adaptor&
341 operator=(const scoped_allocator_adaptor&) = default;
342
343 scoped_allocator_adaptor&
344 operator=(scoped_allocator_adaptor&&) = default;
345
346 inner_allocator_type& inner_allocator() noexcept
347 { return _M_inner._M_get(this); }
348
349 const inner_allocator_type& inner_allocator() const noexcept
350 { return _M_inner._M_get(this); }
351
352 outer_allocator_type& outer_allocator() noexcept
353 { return static_cast<_OuterAlloc&>(*this); }
354
355 const outer_allocator_type& outer_allocator() const noexcept
356 { return static_cast<const _OuterAlloc&>(*this); }
357
358 _GLIBCXX_NODISCARD pointer allocate(size_type __n)
359 { return __traits::allocate(outer_allocator(), __n); }
360
361 _GLIBCXX_NODISCARD pointer allocate(size_type __n, const_void_pointer __hint)
362 { return __traits::allocate(outer_allocator(), __n, __hint); }
363
364 void deallocate(pointer __p, size_type __n)
365 { return __traits::deallocate(outer_allocator(), __p, __n); }
366
367 size_type max_size() const
368 { return __traits::max_size(outer_allocator()); }
369
370#if ! __cpp_lib_make_obj_using_allocator
371 template<typename _Tp, typename... _Args>
372 typename __not_pair<_Tp>::type
373 construct(_Tp* __p, _Args&&... __args)
374 {
375 auto& __inner = inner_allocator();
376 auto __use_tag
377 = std::__use_alloc<_Tp, inner_allocator_type, _Args...>(__inner);
378 _M_construct(__use_tag, __p, std::forward<_Args>(__args)...);
379 }
380
381 template<typename _T1, typename _T2, typename... _Args1,
382 typename... _Args2>
383 void
384 construct(pair<_T1, _T2>* __p, piecewise_construct_t,
385 tuple<_Args1...> __x, tuple<_Args2...> __y)
386 {
387 // _GLIBCXX_RESOLVE_LIB_DEFECTS
388 // 2203. wrong argument types for piecewise construction
389 auto& __inner = inner_allocator();
390 auto __x_use_tag
391 = std::__use_alloc<_T1, inner_allocator_type, _Args1...>(__inner);
392 auto __y_use_tag
393 = std::__use_alloc<_T2, inner_allocator_type, _Args2...>(__inner);
394 typename _Build_index_tuple<sizeof...(_Args1)>::__type __x_indices;
395 typename _Build_index_tuple<sizeof...(_Args2)>::__type __y_indices;
396 typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
397 _O_traits::construct(__outermost(*this), __p, piecewise_construct,
398 _M_construct_p(__x_use_tag, __x_indices, __x),
399 _M_construct_p(__y_use_tag, __y_indices, __y));
400 }
401
402 template<typename _T1, typename _T2>
403 void
404 construct(pair<_T1, _T2>* __p)
405 { construct(__p, piecewise_construct, tuple<>(), tuple<>()); }
406
407 template<typename _T1, typename _T2, typename _Up, typename _Vp>
408 void
409 construct(pair<_T1, _T2>* __p, _Up&& __u, _Vp&& __v)
410 {
411 construct(__p, piecewise_construct,
412 std::forward_as_tuple(std::forward<_Up>(__u)),
413 std::forward_as_tuple(std::forward<_Vp>(__v)));
414 }
415
416 template<typename _T1, typename _T2, typename _Up, typename _Vp>
417 void
418 construct(pair<_T1, _T2>* __p, const pair<_Up, _Vp>& __x)
419 {
420 construct(__p, piecewise_construct,
421 std::forward_as_tuple(__x.first),
422 std::forward_as_tuple(__x.second));
423 }
424
425 template<typename _T1, typename _T2, typename _Up, typename _Vp>
426 void
427 construct(pair<_T1, _T2>* __p, pair<_Up, _Vp>&& __x)
428 {
429 construct(__p, piecewise_construct,
430 std::forward_as_tuple(std::forward<_Up>(__x.first)),
431 std::forward_as_tuple(std::forward<_Vp>(__x.second)));
432 }
433#else // make_obj_using_allocator
434 template<typename _Tp, typename... _Args>
435 __attribute__((__nonnull__))
436 void
437 construct(_Tp* __p, _Args&&... __args)
438 {
439 typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
440 std::apply([__p, this](auto&&... __newargs) {
441 _O_traits::construct(__outermost(*this), __p,
442 std::forward<decltype(__newargs)>(__newargs)...);
443 },
444 uses_allocator_construction_args<_Tp>(inner_allocator(),
445 std::forward<_Args>(__args)...));
446 }
447#endif
448
449 template<typename _Tp>
450 void destroy(_Tp* __p)
451 {
452 typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
453 _O_traits::destroy(__outermost(*this), __p);
454 }
455
456 scoped_allocator_adaptor
457 select_on_container_copy_construction() const
458 {
459 typedef typename _Build_index_tuple<sizeof...(_InnerAllocs)>::__type
460 _Indices;
461 return scoped_allocator_adaptor(_M_tie(), _Indices());
462 }
463
464 template <typename _OutA1, typename _OutA2, typename... _InA>
465 friend bool
466 operator==(const scoped_allocator_adaptor<_OutA1, _InA...>& __a,
467 const scoped_allocator_adaptor<_OutA2, _InA...>& __b) noexcept;
468
469 private:
470#if ! __cpp_lib_make_obj_using_allocator
471 template<typename _Ind, typename... _Args>
472 tuple<_Args&&...>
473 _M_construct_p(__uses_alloc0, _Ind, tuple<_Args...>& __t)
474 { return std::move(__t); }
475
476 template<size_t... _Ind, typename... _Args>
477 tuple<allocator_arg_t, inner_allocator_type&, _Args&&...>
478 _M_construct_p(__uses_alloc1_, _Index_tuple<_Ind...>,
479 tuple<_Args...>& __t)
480 {
481 return { allocator_arg, inner_allocator(),
482 std::get<_Ind>(std::move(__t))...
483 };
484 }
485
486 template<size_t... _Ind, typename... _Args>
487 tuple<_Args&&..., inner_allocator_type&>
488 _M_construct_p(__uses_alloc2_, _Index_tuple<_Ind...>,
489 tuple<_Args...>& __t)
490 {
491 return { std::get<_Ind>(std::move(__t))..., inner_allocator() };
492 }
493#endif // ! make_obj_using_allocator
494 };
495
496 /// @related std::scoped_allocator_adaptor
497 template <typename _OutA1, typename _OutA2, typename... _InA>
498 inline bool
499 operator==(const scoped_allocator_adaptor<_OutA1, _InA...>& __a,
500 const scoped_allocator_adaptor<_OutA2, _InA...>& __b) noexcept
501 {
502 return __a.outer_allocator() == __b.outer_allocator()
503 && __a._M_inner == __b._M_inner;
504 }
505
506#if __cpp_impl_three_way_comparison < 201907L
507 /// @related std::scoped_allocator_adaptor
508 template <typename _OutA1, typename _OutA2, typename... _InA>
509 inline bool
510 operator!=(const scoped_allocator_adaptor<_OutA1, _InA...>& __a,
511 const scoped_allocator_adaptor<_OutA2, _InA...>& __b) noexcept
512 { return !(__a == __b); }
513#endif
514
515 /// @}
516
517_GLIBCXX_END_NAMESPACE_VERSION
518} // namespace
519
520#endif // C++11
521
522#endif // _SCOPED_ALLOCATOR
523

source code of include/c++/11/scoped_allocator