libstdc++
ext/alloc_traits.h
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1 // Allocator traits -*- 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 ext/alloc_traits.h
26  * This file is a GNU extension to the Standard C++ Library.
27  */
28 
29 #ifndef _EXT_ALLOC_TRAITS_H
30 #define _EXT_ALLOC_TRAITS_H 1
31 
32 #pragma GCC system_header
33 
34 # include <bits/alloc_traits.h>
35 #if __cplusplus < 201103L
36 # include <bits/allocator.h> // for __alloc_swap
37 #endif
38 
39 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
40 {
41 _GLIBCXX_BEGIN_NAMESPACE_VERSION
42 
43 /**
44  * @brief Uniform interface to C++98 and C++11 allocators.
45  * @ingroup allocators
46 */
47 template<typename _Alloc, typename = typename _Alloc::value_type>
49 #if __cplusplus >= 201103L
51 #endif
52  {
53  typedef _Alloc allocator_type;
54 #if __cplusplus >= 201103L
56  typedef typename _Base_type::value_type value_type;
57  typedef typename _Base_type::pointer pointer;
59  typedef typename _Base_type::size_type size_type;
61  // C++11 allocators do not define reference or const_reference
62  typedef value_type& reference;
63  typedef const value_type& const_reference;
64  using _Base_type::allocate;
65  using _Base_type::deallocate;
66  using _Base_type::construct;
67  using _Base_type::destroy;
68  using _Base_type::max_size;
69 
70  private:
71  template<typename _Ptr>
72  using __is_custom_pointer
73  = std::__and_<std::is_same<pointer, _Ptr>,
74  std::__not_<std::is_pointer<_Ptr>>>;
75 
76  public:
77  // overload construct for non-standard pointer types
78  template<typename _Ptr, typename... _Args>
79  static _GLIBCXX14_CONSTEXPR
80  std::__enable_if_t<__is_custom_pointer<_Ptr>::value>
81  construct(_Alloc& __a, _Ptr __p, _Args&&... __args)
82  noexcept(noexcept(_Base_type::construct(__a, std::__to_address(__p),
83  std::forward<_Args>(__args)...)))
84  {
85  _Base_type::construct(__a, std::__to_address(__p),
86  std::forward<_Args>(__args)...);
87  }
88 
89  // overload destroy for non-standard pointer types
90  template<typename _Ptr>
91  static _GLIBCXX14_CONSTEXPR
92  std::__enable_if_t<__is_custom_pointer<_Ptr>::value>
93  destroy(_Alloc& __a, _Ptr __p)
94  noexcept(noexcept(_Base_type::destroy(__a, std::__to_address(__p))))
95  { _Base_type::destroy(__a, std::__to_address(__p)); }
96 
97  static constexpr _Alloc _S_select_on_copy(const _Alloc& __a)
98  { return _Base_type::select_on_container_copy_construction(__a); }
99 
100  static _GLIBCXX14_CONSTEXPR void _S_on_swap(_Alloc& __a, _Alloc& __b)
101  { std::__alloc_on_swap(__a, __b); }
102 
103  static constexpr bool _S_propagate_on_copy_assign()
104  { return _Base_type::propagate_on_container_copy_assignment::value; }
105 
106  static constexpr bool _S_propagate_on_move_assign()
107  { return _Base_type::propagate_on_container_move_assignment::value; }
108 
109  static constexpr bool _S_propagate_on_swap()
110  { return _Base_type::propagate_on_container_swap::value; }
111 
112  static constexpr bool _S_always_equal()
113  { return _Base_type::is_always_equal::value; }
114 
115  static constexpr bool _S_nothrow_move()
116  { return _S_propagate_on_move_assign() || _S_always_equal(); }
117 
118  template<typename _Tp>
119  struct rebind
120  { typedef typename _Base_type::template rebind_alloc<_Tp> other; };
121 #else // ! C++11
122 
123  typedef typename _Alloc::pointer pointer;
124  typedef typename _Alloc::const_pointer const_pointer;
125  typedef typename _Alloc::value_type value_type;
126  typedef typename _Alloc::reference reference;
127  typedef typename _Alloc::const_reference const_reference;
128  typedef typename _Alloc::size_type size_type;
129  typedef typename _Alloc::difference_type difference_type;
130 
131  _GLIBCXX_NODISCARD static pointer
132  allocate(_Alloc& __a, size_type __n)
133  { return __a.allocate(__n); }
134 
135  template<typename _Hint>
136  _GLIBCXX_NODISCARD static pointer
137  allocate(_Alloc& __a, size_type __n, _Hint __hint)
138  { return __a.allocate(__n, __hint); }
139 
140  static void deallocate(_Alloc& __a, pointer __p, size_type __n)
141  { __a.deallocate(__p, __n); }
142 
143  template<typename _Tp>
144  static void construct(_Alloc& __a, pointer __p, const _Tp& __arg)
145  { __a.construct(__p, __arg); }
146 
147  static void destroy(_Alloc& __a, pointer __p)
148  { __a.destroy(__p); }
149 
150  static size_type max_size(const _Alloc& __a)
151  { return __a.max_size(); }
152 
153  static const _Alloc& _S_select_on_copy(const _Alloc& __a) { return __a; }
154 
155  static void _S_on_swap(_Alloc& __a, _Alloc& __b)
156  {
157  // _GLIBCXX_RESOLVE_LIB_DEFECTS
158  // 431. Swapping containers with unequal allocators.
159  std::__alloc_swap<_Alloc>::_S_do_it(__a, __b);
160  }
161 
162  template<typename _Tp>
163  struct rebind
164  { typedef typename _Alloc::template rebind<_Tp>::other other; };
165 #endif // C++11
166  };
167 
168 _GLIBCXX_END_NAMESPACE_VERSION
169 } // namespace __gnu_cxx
170 
171 #endif
GNU extensions for public use.
Uniform interface to all allocator types.
__detected_or_t< value_type *, __pointer, _Alloc > pointer
The allocator's pointer type.
typename _Size< _Alloc, difference_type >::type size_type
The allocator's size type.
typename _Diff< _Alloc, pointer >::type difference_type
The allocator's difference type.
typename _Ptr< __c_pointer, const value_type >::type const_pointer
The allocator's const pointer type.
_Alloc::value_type value_type
The allocated type.
_Alloc allocator_type
The allocator type.
Uniform interface to C++98 and C++11 allocators.