1// Allocator traits -*- C++ -*-
2
3// Copyright (C) 2011-2015 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 bits/alloc_traits.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 _ALLOC_TRAITS_H
31#define _ALLOC_TRAITS_H 1
32
33#if __cplusplus >= 201103L
34
35#include <bits/memoryfwd.h>
36#include <bits/ptr_traits.h>
37#include <ext/numeric_traits.h>
38
39namespace std _GLIBCXX_VISIBILITY(default)
40{
41_GLIBCXX_BEGIN_NAMESPACE_VERSION
42
43 template<typename _Alloc, typename _Tp>
44 class __alloctr_rebind_helper
45 {
46 template<typename _Alloc2, typename _Tp2>
47 static constexpr true_type
48 _S_chk(typename _Alloc2::template rebind<_Tp2>::other*);
49
50 template<typename, typename>
51 static constexpr false_type
52 _S_chk(...);
53
54 public:
55 using __type = decltype(_S_chk<_Alloc, _Tp>(nullptr));
56 };
57
58 template<typename _Alloc, typename _Tp,
59 bool = __alloctr_rebind_helper<_Alloc, _Tp>::__type::value>
60 struct __alloctr_rebind;
61
62 template<typename _Alloc, typename _Tp>
63 struct __alloctr_rebind<_Alloc, _Tp, true>
64 {
65 typedef typename _Alloc::template rebind<_Tp>::other __type;
66 };
67
68 template<template<typename, typename...> class _Alloc, typename _Tp,
69 typename _Up, typename... _Args>
70 struct __alloctr_rebind<_Alloc<_Up, _Args...>, _Tp, false>
71 {
72 typedef _Alloc<_Tp, _Args...> __type;
73 };
74
75 template<typename _Alloc, typename _Tp>
76 using __alloc_rebind = typename __alloctr_rebind<_Alloc, _Tp>::__type;
77
78 /**
79 * @brief Uniform interface to all allocator types.
80 * @ingroup allocators
81 */
82 template<typename _Alloc>
83 struct allocator_traits
84 {
85 /// The allocator type
86 typedef _Alloc allocator_type;
87 /// The allocated type
88 typedef typename _Alloc::value_type value_type;
89
90#define _GLIBCXX_ALLOC_TR_NESTED_TYPE(_NTYPE, _ALT) \
91 private: \
92 template<typename _Tp> \
93 static typename _Tp::_NTYPE _S_##_NTYPE##_helper(_Tp*); \
94 static _ALT _S_##_NTYPE##_helper(...); \
95 typedef decltype(_S_##_NTYPE##_helper((_Alloc*)0)) __##_NTYPE; \
96 public:
97
98_GLIBCXX_ALLOC_TR_NESTED_TYPE(pointer, value_type*)
99
100 /**
101 * @brief The allocator's pointer type.
102 *
103 * @c Alloc::pointer if that type exists, otherwise @c value_type*
104 */
105 typedef __pointer pointer;
106
107_GLIBCXX_ALLOC_TR_NESTED_TYPE(const_pointer,
108 typename pointer_traits<pointer>::template rebind<const value_type>)
109
110 /**
111 * @brief The allocator's const pointer type.
112 *
113 * @c Alloc::const_pointer if that type exists, otherwise
114 * <tt> pointer_traits<pointer>::rebind<const value_type> </tt>
115 */
116 typedef __const_pointer const_pointer;
117
118_GLIBCXX_ALLOC_TR_NESTED_TYPE(void_pointer,
119 typename pointer_traits<pointer>::template rebind<void>)
120
121 /**
122 * @brief The allocator's void pointer type.
123 *
124 * @c Alloc::void_pointer if that type exists, otherwise
125 * <tt> pointer_traits<pointer>::rebind<void> </tt>
126 */
127 typedef __void_pointer void_pointer;
128
129_GLIBCXX_ALLOC_TR_NESTED_TYPE(const_void_pointer,
130 typename pointer_traits<pointer>::template rebind<const void>)
131
132 /**
133 * @brief The allocator's const void pointer type.
134 *
135 * @c Alloc::const_void_pointer if that type exists, otherwise
136 * <tt> pointer_traits<pointer>::rebind<const void> </tt>
137 */
138 typedef __const_void_pointer const_void_pointer;
139
140_GLIBCXX_ALLOC_TR_NESTED_TYPE(difference_type,
141 typename pointer_traits<pointer>::difference_type)
142
143 /**
144 * @brief The allocator's difference type
145 *
146 * @c Alloc::difference_type if that type exists, otherwise
147 * <tt> pointer_traits<pointer>::difference_type </tt>
148 */
149 typedef __difference_type difference_type;
150
151_GLIBCXX_ALLOC_TR_NESTED_TYPE(size_type,
152 typename make_unsigned<difference_type>::type)
153
154 /**
155 * @brief The allocator's size type
156 *
157 * @c Alloc::size_type if that type exists, otherwise
158 * <tt> make_unsigned<difference_type>::type </tt>
159 */
160 typedef __size_type size_type;
161
162_GLIBCXX_ALLOC_TR_NESTED_TYPE(propagate_on_container_copy_assignment,
163 false_type)
164
165 /**
166 * @brief How the allocator is propagated on copy assignment
167 *
168 * @c Alloc::propagate_on_container_copy_assignment if that type exists,
169 * otherwise @c false_type
170 */
171 typedef __propagate_on_container_copy_assignment
172 propagate_on_container_copy_assignment;
173
174_GLIBCXX_ALLOC_TR_NESTED_TYPE(propagate_on_container_move_assignment,
175 false_type)
176
177 /**
178 * @brief How the allocator is propagated on move assignment
179 *
180 * @c Alloc::propagate_on_container_move_assignment if that type exists,
181 * otherwise @c false_type
182 */
183 typedef __propagate_on_container_move_assignment
184 propagate_on_container_move_assignment;
185
186_GLIBCXX_ALLOC_TR_NESTED_TYPE(propagate_on_container_swap,
187 false_type)
188
189 /**
190 * @brief How the allocator is propagated on swap
191 *
192 * @c Alloc::propagate_on_container_swap if that type exists,
193 * otherwise @c false_type
194 */
195 typedef __propagate_on_container_swap propagate_on_container_swap;
196
197#undef _GLIBCXX_ALLOC_TR_NESTED_TYPE
198
199 template<typename _Tp>
200 using rebind_alloc = typename __alloctr_rebind<_Alloc, _Tp>::__type;
201 template<typename _Tp>
202 using rebind_traits = allocator_traits<rebind_alloc<_Tp>>;
203
204 private:
205 template<typename _Alloc2>
206 struct __allocate_helper
207 {
208 template<typename _Alloc3,
209 typename = decltype(std::declval<_Alloc3*>()->allocate(
210 std::declval<size_type>(),
211 std::declval<const_void_pointer>()))>
212 static true_type __test(int);
213
214 template<typename>
215 static false_type __test(...);
216
217 using type = decltype(__test<_Alloc>(0));
218 };
219
220 template<typename _Alloc2>
221 using __has_allocate = typename __allocate_helper<_Alloc2>::type;
222
223 template<typename _Alloc2,
224 typename = _Require<__has_allocate<_Alloc2>>>
225 static pointer
226 _S_allocate(_Alloc2& __a, size_type __n, const_void_pointer __hint)
227 { return __a.allocate(__n, __hint); }
228
229 template<typename _Alloc2, typename _UnusedHint,
230 typename = _Require<__not_<__has_allocate<_Alloc2>>>>
231 static pointer
232 _S_allocate(_Alloc2& __a, size_type __n, _UnusedHint)
233 { return __a.allocate(__n); }
234
235 template<typename _Tp, typename... _Args>
236 struct __construct_helper
237 {
238 template<typename _Alloc2,
239 typename = decltype(std::declval<_Alloc2*>()->construct(
240 std::declval<_Tp*>(), std::declval<_Args>()...))>
241 static true_type __test(int);
242
243 template<typename>
244 static false_type __test(...);
245
246 using type = decltype(__test<_Alloc>(0));
247 };
248
249 template<typename _Tp, typename... _Args>
250 using __has_construct
251 = typename __construct_helper<_Tp, _Args...>::type;
252
253 template<typename _Tp, typename... _Args>
254 static _Require<__has_construct<_Tp, _Args...>>
255 _S_construct(_Alloc& __a, _Tp* __p, _Args&&... __args)
256 { __a.construct(__p, std::forward<_Args>(__args)...); }
257
258 template<typename _Tp, typename... _Args>
259 static
260 _Require<__and_<__not_<__has_construct<_Tp, _Args...>>,
261 is_constructible<_Tp, _Args...>>>
262 _S_construct(_Alloc&, _Tp* __p, _Args&&... __args)
263 { ::new((void*)__p) _Tp(std::forward<_Args>(__args)...); }
264
265 template<typename _Tp>
266 struct __destroy_helper
267 {
268 template<typename _Alloc2,
269 typename = decltype(std::declval<_Alloc2*>()->destroy(
270 std::declval<_Tp*>()))>
271 static true_type __test(int);
272
273 template<typename>
274 static false_type __test(...);
275
276 using type = decltype(__test<_Alloc>(0));
277 };
278
279 template<typename _Tp>
280 using __has_destroy = typename __destroy_helper<_Tp>::type;
281
282 template<typename _Tp>
283 static _Require<__has_destroy<_Tp>>
284 _S_destroy(_Alloc& __a, _Tp* __p)
285 { __a.destroy(__p); }
286
287 template<typename _Tp>
288 static _Require<__not_<__has_destroy<_Tp>>>
289 _S_destroy(_Alloc&, _Tp* __p)
290 { __p->~_Tp(); }
291
292 template<typename _Alloc2>
293 struct __maxsize_helper
294 {
295 template<typename _Alloc3,
296 typename = decltype(std::declval<_Alloc3*>()->max_size())>
297 static true_type __test(int);
298
299 template<typename>
300 static false_type __test(...);
301
302 using type = decltype(__test<_Alloc2>(0));
303 };
304
305 template<typename _Alloc2>
306 using __has_max_size = typename __maxsize_helper<_Alloc2>::type;
307
308 template<typename _Alloc2,
309 typename = _Require<__has_max_size<_Alloc2>>>
310 static size_type
311 _S_max_size(_Alloc2& __a, int)
312 { return __a.max_size(); }
313
314 template<typename _Alloc2,
315 typename = _Require<__not_<__has_max_size<_Alloc2>>>>
316 static size_type
317 _S_max_size(_Alloc2&, ...)
318 { return __gnu_cxx::__numeric_traits<size_type>::__max; }
319
320 template<typename _Alloc2>
321 struct __select_helper
322 {
323 template<typename _Alloc3, typename
324 = decltype(std::declval<_Alloc3*>()
325 ->select_on_container_copy_construction())>
326 static true_type __test(int);
327
328 template<typename>
329 static false_type __test(...);
330
331 using type = decltype(__test<_Alloc2>(0));
332 };
333
334 template<typename _Alloc2>
335 using __has_soccc = typename __select_helper<_Alloc2>::type;
336
337 template<typename _Alloc2,
338 typename = _Require<__has_soccc<_Alloc2>>>
339 static _Alloc2
340 _S_select(_Alloc2& __a, int)
341 { return __a.select_on_container_copy_construction(); }
342
343 template<typename _Alloc2,
344 typename = _Require<__not_<__has_soccc<_Alloc2>>>>
345 static _Alloc2
346 _S_select(_Alloc2& __a, ...)
347 { return __a; }
348
349 public:
350
351 /**
352 * @brief Allocate memory.
353 * @param __a An allocator.
354 * @param __n The number of objects to allocate space for.
355 *
356 * Calls @c a.allocate(n)
357 */
358 static pointer
359 allocate(_Alloc& __a, size_type __n)
360 { return __a.allocate(__n); }
361
362 /**
363 * @brief Allocate memory.
364 * @param __a An allocator.
365 * @param __n The number of objects to allocate space for.
366 * @param __hint Aid to locality.
367 * @return Memory of suitable size and alignment for @a n objects
368 * of type @c value_type
369 *
370 * Returns <tt> a.allocate(n, hint) </tt> if that expression is
371 * well-formed, otherwise returns @c a.allocate(n)
372 */
373 static pointer
374 allocate(_Alloc& __a, size_type __n, const_void_pointer __hint)
375 { return _S_allocate(__a, __n, __hint); }
376
377 /**
378 * @brief Deallocate memory.
379 * @param __a An allocator.
380 * @param __p Pointer to the memory to deallocate.
381 * @param __n The number of objects space was allocated for.
382 *
383 * Calls <tt> a.deallocate(p, n) </tt>
384 */
385 static void deallocate(_Alloc& __a, pointer __p, size_type __n)
386 { __a.deallocate(__p, __n); }
387
388 /**
389 * @brief Construct an object of type @a _Tp
390 * @param __a An allocator.
391 * @param __p Pointer to memory of suitable size and alignment for Tp
392 * @param __args Constructor arguments.
393 *
394 * Calls <tt> __a.construct(__p, std::forward<Args>(__args)...) </tt>
395 * if that expression is well-formed, otherwise uses placement-new
396 * to construct an object of type @a _Tp at location @a __p from the
397 * arguments @a __args...
398 */
399 template<typename _Tp, typename... _Args>
400 static auto construct(_Alloc& __a, _Tp* __p, _Args&&... __args)
401 -> decltype(_S_construct(__a, __p, std::forward<_Args>(__args)...))
402 { _S_construct(__a, __p, std::forward<_Args>(__args)...); }
403
404 /**
405 * @brief Destroy an object of type @a _Tp
406 * @param __a An allocator.
407 * @param __p Pointer to the object to destroy
408 *
409 * Calls @c __a.destroy(__p) if that expression is well-formed,
410 * otherwise calls @c __p->~_Tp()
411 */
412 template <class _Tp>
413 static void destroy(_Alloc& __a, _Tp* __p)
414 { _S_destroy(__a, __p); }
415
416 /**
417 * @brief The maximum supported allocation size
418 * @param __a An allocator.
419 * @return @c __a.max_size() or @c numeric_limits<size_type>::max()
420 *
421 * Returns @c __a.max_size() if that expression is well-formed,
422 * otherwise returns @c numeric_limits<size_type>::max()
423 */
424 static size_type max_size(const _Alloc& __a) noexcept
425 { return _S_max_size(__a, 0); }
426
427 /**
428 * @brief Obtain an allocator to use when copying a container.
429 * @param __rhs An allocator.
430 * @return @c __rhs.select_on_container_copy_construction() or @a __rhs
431 *
432 * Returns @c __rhs.select_on_container_copy_construction() if that
433 * expression is well-formed, otherwise returns @a __rhs
434 */
435 static _Alloc
436 select_on_container_copy_construction(const _Alloc& __rhs)
437 { return _S_select(__rhs, 0); }
438 };
439
440 template<typename _Alloc>
441 inline void
442 __do_alloc_on_copy(_Alloc& __one, const _Alloc& __two, true_type)
443 { __one = __two; }
444
445 template<typename _Alloc>
446 inline void
447 __do_alloc_on_copy(_Alloc&, const _Alloc&, false_type)
448 { }
449
450 template<typename _Alloc>
451 inline void __alloc_on_copy(_Alloc& __one, const _Alloc& __two)
452 {
453 typedef allocator_traits<_Alloc> __traits;
454 typedef typename __traits::propagate_on_container_copy_assignment __pocca;
455 __do_alloc_on_copy(__one, __two, __pocca());
456 }
457
458 template<typename _Alloc>
459 inline _Alloc __alloc_on_copy(const _Alloc& __a)
460 {
461 typedef allocator_traits<_Alloc> __traits;
462 return __traits::select_on_container_copy_construction(__a);
463 }
464
465 template<typename _Alloc>
466 inline void __do_alloc_on_move(_Alloc& __one, _Alloc& __two, true_type)
467 { __one = std::move(__two); }
468
469 template<typename _Alloc>
470 inline void __do_alloc_on_move(_Alloc&, _Alloc&, false_type)
471 { }
472
473 template<typename _Alloc>
474 inline void __alloc_on_move(_Alloc& __one, _Alloc& __two)
475 {
476 typedef allocator_traits<_Alloc> __traits;
477 typedef typename __traits::propagate_on_container_move_assignment __pocma;
478 __do_alloc_on_move(__one, __two, __pocma());
479 }
480
481 template<typename _Alloc>
482 inline void __do_alloc_on_swap(_Alloc& __one, _Alloc& __two, true_type)
483 {
484 using std::swap;
485 swap(__one, __two);
486 }
487
488 template<typename _Alloc>
489 inline void __do_alloc_on_swap(_Alloc&, _Alloc&, false_type)
490 { }
491
492 template<typename _Alloc>
493 inline void __alloc_on_swap(_Alloc& __one, _Alloc& __two)
494 {
495 typedef allocator_traits<_Alloc> __traits;
496 typedef typename __traits::propagate_on_container_swap __pocs;
497 __do_alloc_on_swap(__one, __two, __pocs());
498 }
499
500 template<typename _Alloc>
501 class __is_copy_insertable_impl
502 {
503 typedef allocator_traits<_Alloc> _Traits;
504
505 template<typename _Up, typename
506 = decltype(_Traits::construct(std::declval<_Alloc&>(),
507 std::declval<_Up*>(),
508 std::declval<const _Up&>()))>
509 static true_type
510 _M_select(int);
511
512 template<typename _Up>
513 static false_type
514 _M_select(...);
515
516 public:
517 typedef decltype(_M_select<typename _Alloc::value_type>(0)) type;
518 };
519
520 // true if _Alloc::value_type is CopyInsertable into containers using _Alloc
521 template<typename _Alloc>
522 struct __is_copy_insertable
523 : __is_copy_insertable_impl<_Alloc>::type
524 { };
525
526 // std::allocator<_Tp> just requires CopyConstructible
527 template<typename _Tp>
528 struct __is_copy_insertable<allocator<_Tp>>
529 : is_copy_constructible<_Tp>
530 { };
531
532_GLIBCXX_END_NAMESPACE_VERSION
533} // namespace std
534
535#endif
536#endif
537