1 // Allocator traits -*- C++ -*-
3 // Copyright (C) 2011-2012 Free Software Foundation, Inc.
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)
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.
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.
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/>.
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}
30 #ifndef _ALLOC_TRAITS_H
31 #define _ALLOC_TRAITS_H 1
33 #ifdef __GXX_EXPERIMENTAL_CXX0X__
35 #include <bits/ptr_traits.h>
36 #include <ext/numeric_traits.h>
38 namespace std
_GLIBCXX_VISIBILITY(default)
40 _GLIBCXX_BEGIN_NAMESPACE_VERSION
42 template<typename _Alloc
, typename _Tp
>
43 class __alloctr_rebind_helper
45 template<typename _Alloc2
, typename _Tp2
>
47 _S_chk(typename
_Alloc2::template rebind
<_Tp2
>::other
*)
50 template<typename
, typename
>
56 static const bool __value
= _S_chk
<_Alloc
, _Tp
>(nullptr);
59 template<typename _Alloc
, typename _Tp
>
60 const bool __alloctr_rebind_helper
<_Alloc
, _Tp
>::__value
;
62 template<typename _Alloc
, typename _Tp
,
63 bool = __alloctr_rebind_helper
<_Alloc
, _Tp
>::__value
>
64 struct __alloctr_rebind
;
66 template<typename _Alloc
, typename _Tp
>
67 struct __alloctr_rebind
<_Alloc
, _Tp
, true>
69 typedef typename
_Alloc::template rebind
<_Tp
>::other __type
;
72 template<template<typename
, typename
...> class _Alloc
, typename _Tp
,
73 typename _Up
, typename
... _Args
>
74 struct __alloctr_rebind
<_Alloc
<_Up
, _Args
...>, _Tp
, false>
76 typedef _Alloc
<_Tp
, _Args
...> __type
;
80 * @brief Uniform interface to all allocator types.
83 template<typename _Alloc
>
84 struct allocator_traits
86 /// The allocator type
87 typedef _Alloc allocator_type
;
88 /// The allocated type
89 typedef typename
_Alloc::value_type value_type
;
91 #define _GLIBCXX_ALLOC_TR_NESTED_TYPE(_NTYPE, _ALT) \
93 template<typename _Tp> \
94 static typename _Tp::_NTYPE _S_##_NTYPE##_helper(_Tp*); \
95 static _ALT _S_##_NTYPE##_helper(...); \
96 typedef decltype(_S_##_NTYPE##_helper((_Alloc*)0)) __##_NTYPE; \
99 _GLIBCXX_ALLOC_TR_NESTED_TYPE(pointer
, value_type
*)
102 * @brief The allocator's pointer type.
104 * @c Alloc::pointer if that type exists, otherwise @c value_type*
106 typedef __pointer pointer
;
108 _GLIBCXX_ALLOC_TR_NESTED_TYPE(const_pointer
,
109 typename pointer_traits
<pointer
>::template rebind
<const value_type
>)
112 * @brief The allocator's const pointer type.
114 * @c Alloc::const_pointer if that type exists, otherwise
115 * <tt> pointer_traits<pointer>::rebind<const value_type> </tt>
117 typedef __const_pointer const_pointer
;
119 _GLIBCXX_ALLOC_TR_NESTED_TYPE(void_pointer
,
120 typename pointer_traits
<pointer
>::template rebind
<void>)
123 * @brief The allocator's void pointer type.
125 * @c Alloc::void_pointer if that type exists, otherwise
126 * <tt> pointer_traits<pointer>::rebind<void> </tt>
128 typedef __void_pointer void_pointer
;
130 _GLIBCXX_ALLOC_TR_NESTED_TYPE(const_void_pointer
,
131 typename pointer_traits
<pointer
>::template rebind
<const void>)
134 * @brief The allocator's const void pointer type.
136 * @c Alloc::const_void_pointer if that type exists, otherwise
137 * <tt> pointer_traits<pointer>::rebind<const void> </tt>
139 typedef __const_void_pointer const_void_pointer
;
141 _GLIBCXX_ALLOC_TR_NESTED_TYPE(difference_type
,
142 typename pointer_traits
<pointer
>::difference_type
)
145 * @brief The allocator's difference type
147 * @c Alloc::difference_type if that type exists, otherwise
148 * <tt> pointer_traits<pointer>::difference_type </tt>
150 typedef __difference_type difference_type
;
152 _GLIBCXX_ALLOC_TR_NESTED_TYPE(size_type
,
153 typename make_unsigned
<difference_type
>::type
)
156 * @brief The allocator's size type
158 * @c Alloc::size_type if that type exists, otherwise
159 * <tt> make_unsigned<difference_type>::type </tt>
161 typedef __size_type size_type
;
163 _GLIBCXX_ALLOC_TR_NESTED_TYPE(propagate_on_container_copy_assignment
,
167 * @brief How the allocator is propagated on copy assignment
169 * @c Alloc::propagate_on_container_copy_assignment if that type exists,
170 * otherwise @c false_type
172 typedef __propagate_on_container_copy_assignment
173 propagate_on_container_copy_assignment
;
175 _GLIBCXX_ALLOC_TR_NESTED_TYPE(propagate_on_container_move_assignment
,
179 * @brief How the allocator is propagated on move assignment
181 * @c Alloc::propagate_on_container_move_assignment if that type exists,
182 * otherwise @c false_type
184 typedef __propagate_on_container_move_assignment
185 propagate_on_container_move_assignment
;
187 _GLIBCXX_ALLOC_TR_NESTED_TYPE(propagate_on_container_swap
,
191 * @brief How the allocator is propagated on swap
193 * @c Alloc::propagate_on_container_swap if that type exists,
194 * otherwise @c false_type
196 typedef __propagate_on_container_swap propagate_on_container_swap
;
198 #undef _GLIBCXX_ALLOC_TR_NESTED_TYPE
200 template<typename _Tp
>
201 using rebind_alloc
= typename __alloctr_rebind
<_Alloc
, _Tp
>::__type
;
202 template<typename _Tp
>
203 using rebind_traits
= allocator_traits
<rebind_alloc
<_Tp
>>;
206 template<typename _Alloc2
>
207 struct __allocate_helper
209 template<typename _Alloc3
,
210 typename
= decltype(std::declval
<_Alloc3
*>()->allocate(
211 std::declval
<size_type
>(),
212 std::declval
<const_void_pointer
>()))>
213 static true_type
__test(int);
216 static false_type
__test(...);
218 typedef decltype(__test
<_Alloc
>(0)) type
;
219 static const bool value
= type::value
;
222 template<typename _Alloc2
>
224 enable_if
<__allocate_helper
<_Alloc2
>::value
, pointer
>::type
225 _S_allocate(_Alloc2
& __a
, size_type __n
, const_void_pointer __hint
)
226 { return __a
.allocate(__n
, __hint
); }
228 template<typename _Alloc2
>
230 enable_if
<!__allocate_helper
<_Alloc2
>::value
, pointer
>::type
231 _S_allocate(_Alloc2
& __a
, size_type __n
, ...)
232 { return __a
.allocate(__n
); }
234 template<typename _Tp
, typename
... _Args
>
235 struct __construct_helper
237 template<typename _Alloc2
,
238 typename
= decltype(std::declval
<_Alloc2
*>()->construct(
239 std::declval
<_Tp
*>(), std::declval
<_Args
>()...))>
240 static true_type
__test(int);
243 static false_type
__test(...);
245 typedef decltype(__test
<_Alloc
>(0)) type
;
246 static const bool value
= type::value
;
249 template<typename _Tp
, typename
... _Args
>
251 enable_if
<__construct_helper
<_Tp
, _Args
...>::value
, void>::type
252 _S_construct(_Alloc
& __a
, _Tp
* __p
, _Args
&&... __args
)
253 { __a
.construct(__p
, std::forward
<_Args
>(__args
)...); }
255 template<typename _Tp
, typename
... _Args
>
257 enable_if
<!__construct_helper
<_Tp
, _Args
...>::value
, void>::type
258 _S_construct(_Alloc
&, _Tp
* __p
, _Args
&&... __args
)
259 { ::new((void*)__p
) _Tp(std::forward
<_Args
>(__args
)...); }
261 template<typename _Tp
>
262 struct __destroy_helper
264 template<typename _Alloc2
,
265 typename
= decltype(std::declval
<_Alloc2
*>()->destroy(
266 std::declval
<_Tp
*>()))>
267 static true_type
__test(int);
270 static false_type
__test(...);
272 typedef decltype(__test
<_Alloc
>(0)) type
;
273 static const bool value
= type::value
;
276 template<typename _Tp
>
277 static typename enable_if
<__destroy_helper
<_Tp
>::value
, void>::type
278 _S_destroy(_Alloc
& __a
, _Tp
* __p
)
279 { __a
.destroy(__p
); }
281 template<typename _Tp
>
282 static typename enable_if
<!__destroy_helper
<_Tp
>::value
, void>::type
283 _S_destroy(_Alloc
&, _Tp
* __p
)
286 template<typename _Alloc2
>
287 struct __maxsize_helper
289 template<typename _Alloc3
,
290 typename
= decltype(std::declval
<_Alloc3
*>()->max_size())>
291 static true_type
__test(int);
294 static false_type
__test(...);
296 typedef decltype(__test
<_Alloc2
>(0)) type
;
297 static const bool value
= type::value
;
300 template<typename _Alloc2
>
302 enable_if
<__maxsize_helper
<_Alloc2
>::value
, size_type
>::type
303 _S_max_size(_Alloc2
& __a
)
304 { return __a
.max_size(); }
306 template<typename _Alloc2
>
308 enable_if
<!__maxsize_helper
<_Alloc2
>::value
, size_type
>::type
309 _S_max_size(_Alloc2
&)
310 { return __gnu_cxx::__numeric_traits
<size_type
>::__max
; }
312 template<typename _Alloc2
>
313 struct __select_helper
315 template<typename _Alloc3
, typename
316 = decltype(std::declval
<_Alloc3
*>()
317 ->select_on_container_copy_construction())>
318 static true_type
__test(int);
321 static false_type
__test(...);
323 typedef decltype(__test
<_Alloc2
>(0)) type
;
324 static const bool value
= type::value
;
326 template<typename _Alloc2
>
328 enable_if
<__select_helper
<_Alloc2
>::value
, _Alloc2
>::type
329 _S_select(_Alloc2
& __a
)
330 { return __a
.select_on_container_copy_construction(); }
332 template<typename _Alloc2
>
334 enable_if
<!__select_helper
<_Alloc2
>::value
, _Alloc2
>::type
335 _S_select(_Alloc2
& __a
)
341 * @brief Allocate memory.
342 * @param __a An allocator.
343 * @param __n The number of objects to allocate space for.
345 * Calls @c a.allocate(n)
348 allocate(_Alloc
& __a
, size_type __n
)
349 { return __a
.allocate(__n
); }
352 * @brief Allocate memory.
353 * @param __a An allocator.
354 * @param __n The number of objects to allocate space for.
355 * @param __hint Aid to locality.
356 * @return Memory of suitable size and alignment for @a n objects
357 * of type @c value_type
359 * Returns <tt> a.allocate(n, hint) </tt> if that expression is
360 * well-formed, otherwise returns @c a.allocate(n)
363 allocate(_Alloc
& __a
, size_type __n
, const_void_pointer __hint
)
364 { return _S_allocate(__a
, __n
, __hint
); }
367 * @brief Deallocate memory.
368 * @param __a An allocator.
369 * @param __p Pointer to the memory to deallocate.
370 * @param __n The number of objects space was allocated for.
372 * Calls <tt> a.deallocate(p, n) </tt>
374 static void deallocate(_Alloc
& __a
, pointer __p
, size_type __n
)
375 { __a
.deallocate(__p
, __n
); }
378 * @brief Construct an object of type @a _Tp
379 * @param __a An allocator.
380 * @param __p Pointer to memory of suitable size and alignment for Tp
381 * @param __args Constructor arguments.
383 * Calls <tt> __a.construct(__p, std::forward<Args>(__args)...) </tt>
384 * if that expression is well-formed, otherwise uses placement-new
385 * to construct an object of type @a _Tp at location @a __p from the
386 * arguments @a __args...
388 template<typename _Tp
, typename
... _Args
>
389 static void construct(_Alloc
& __a
, _Tp
* __p
, _Args
&&... __args
)
390 { _S_construct(__a
, __p
, std::forward
<_Args
>(__args
)...); }
393 * @brief Destroy an object of type @a _Tp
394 * @param __a An allocator.
395 * @param __p Pointer to the object to destroy
397 * Calls @c __a.destroy(__p) if that expression is well-formed,
398 * otherwise calls @c __p->~_Tp()
401 static void destroy(_Alloc
& __a
, _Tp
* __p
)
402 { _S_destroy(__a
, __p
); }
405 * @brief The maximum supported allocation size
406 * @param __a An allocator.
407 * @return @c __a.max_size() or @c numeric_limits<size_type>::max()
409 * Returns @c __a.max_size() if that expression is well-formed,
410 * otherwise returns @c numeric_limits<size_type>::max()
412 static size_type
max_size(const _Alloc
& __a
)
413 { return _S_max_size(__a
); }
416 * @brief Obtain an allocator to use when copying a container.
417 * @param __rhs An allocator.
418 * @return @c __rhs.select_on_container_copy_construction() or @a __rhs
420 * Returns @c __rhs.select_on_container_copy_construction() if that
421 * expression is well-formed, otherwise returns @a __rhs
424 select_on_container_copy_construction(const _Alloc
& __rhs
)
425 { return _S_select(__rhs
); }
428 template<typename _Alloc
>
429 template<typename _Alloc2
>
430 const bool allocator_traits
<_Alloc
>::__allocate_helper
<_Alloc2
>::value
;
432 template<typename _Alloc
>
433 template<typename _Tp
, typename
... _Args
>
435 allocator_traits
<_Alloc
>::__construct_helper
<_Tp
, _Args
...>::value
;
437 template<typename _Alloc
>
438 template<typename _Tp
>
439 const bool allocator_traits
<_Alloc
>::__destroy_helper
<_Tp
>::value
;
441 template<typename _Alloc
>
442 template<typename _Alloc2
>
443 const bool allocator_traits
<_Alloc
>::__maxsize_helper
<_Alloc2
>::value
;
445 template<typename _Alloc
>
446 template<typename _Alloc2
>
447 const bool allocator_traits
<_Alloc
>::__select_helper
<_Alloc2
>::value
;
449 template<typename _Alloc
>
451 __do_alloc_on_copy(_Alloc
& __one
, const _Alloc
& __two
, true_type
)
454 template<typename _Alloc
>
456 __do_alloc_on_copy(_Alloc
&, const _Alloc
&, false_type
)
459 template<typename _Alloc
>
460 inline void __alloc_on_copy(_Alloc
& __one
, const _Alloc
& __two
)
462 typedef allocator_traits
<_Alloc
> __traits
;
463 typedef typename
__traits::propagate_on_container_copy_assignment __pocca
;
464 __do_alloc_on_copy(__one
, __two
, __pocca());
467 template<typename _Alloc
>
468 inline _Alloc
__alloc_on_copy(const _Alloc
& __a
)
470 typedef allocator_traits
<_Alloc
> __traits
;
471 return __traits::select_on_container_copy_construction(__a
);
474 template<typename _Alloc
>
475 inline void __do_alloc_on_move(_Alloc
& __one
, _Alloc
& __two
, true_type
)
476 { __one
= std::move(__two
); }
478 template<typename _Alloc
>
479 inline void __do_alloc_on_move(_Alloc
&, _Alloc
&, false_type
)
482 template<typename _Alloc
>
483 inline void __alloc_on_move(_Alloc
& __one
, _Alloc
& __two
)
485 typedef allocator_traits
<_Alloc
> __traits
;
486 typedef typename
__traits::propagate_on_container_move_assignment __pocma
;
487 __do_alloc_on_move(__one
, __two
, __pocma());
490 template<typename _Alloc
>
491 inline void __do_alloc_on_swap(_Alloc
& __one
, _Alloc
& __two
, true_type
)
497 template<typename _Alloc
>
498 inline void __do_alloc_on_swap(_Alloc
&, _Alloc
&, false_type
)
501 template<typename _Alloc
>
502 inline void __alloc_on_swap(_Alloc
& __one
, _Alloc
& __two
)
504 typedef allocator_traits
<_Alloc
> __traits
;
505 typedef typename
__traits::propagate_on_container_swap __pocs
;
506 __do_alloc_on_swap(__one
, __two
, __pocs());
509 _GLIBCXX_END_NAMESPACE_VERSION