1 // Allocators -*- C++ -*-
2
3 // Copyright (C) 2001-2016 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 /*
26 * Copyright (c) 1996-1997
27 * Silicon Graphics Computer Systems, Inc.
28 *
29 * Permission to use, copy, modify, distribute and sell this software
30 * and its documentation for any purpose is hereby granted without fee,
31 * provided that the above copyright notice appear in all copies and
32 * that both that copyright notice and this permission notice appear
33 * in supporting documentation. Silicon Graphics makes no
34 * representations about the suitability of this software for any
35 * purpose. It is provided "as is" without express or implied warranty.
36 */
37
38 /** @file bits/allocator.h
39 * This is an internal header file, included by other library headers.
40 * Do not attempt to use it directly. @headername{memory}
41 */
42
43 #ifndef _ALLOCATOR_H
44 #define _ALLOCATOR_H 1
45
46 #include <bits/c++allocator.h> // Define the base class to std::allocator.
47 #include <bits/memoryfwd.h>
48 #if __cplusplus >= 201103L
49 #include <type_traits>
50 #endif
51
52 #define __cpp_lib_incomplete_container_elements 201505
53 #if __cplusplus >= 201103L
54 # define __cpp_lib_allocator_is_always_equal 201411
55 #endif
56
_GLIBCXX_VISIBILITY(default)57 namespace std _GLIBCXX_VISIBILITY(default)
58 {
59 _GLIBCXX_BEGIN_NAMESPACE_VERSION
60
61 /**
62 * @addtogroup allocators
63 * @{
64 */
65
66 /// allocator<void> specialization.
67 template<>
68 class allocator<void>
69 {
70 public:
71 typedef size_t size_type;
72 typedef ptrdiff_t difference_type;
73 typedef void* pointer;
74 typedef const void* const_pointer;
75 typedef void value_type;
76
77 template<typename _Tp1>
78 struct rebind
79 { typedef allocator<_Tp1> other; };
80
81 #if __cplusplus >= 201103L
82 // _GLIBCXX_RESOLVE_LIB_DEFECTS
83 // 2103. std::allocator propagate_on_container_move_assignment
84 typedef true_type propagate_on_container_move_assignment;
85
86 typedef true_type is_always_equal;
87
88 template<typename _Up, typename... _Args>
89 void
90 construct(_Up* __p, _Args&&... __args)
91 { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
92
93 template<typename _Up>
94 void
95 destroy(_Up* __p) { __p->~_Up(); }
96 #endif
97 };
98
99 /**
100 * @brief The @a standard allocator, as per [20.4].
101 *
102 * See https://gcc.gnu.org/onlinedocs/libstdc++/manual/memory.html#std.util.memory.allocator
103 * for further details.
104 *
105 * @tparam _Tp Type of allocated object.
106 */
107 template<typename _Tp>
108 class allocator: public __allocator_base<_Tp>
109 {
110 public:
111 typedef size_t size_type;
112 typedef ptrdiff_t difference_type;
113 typedef _Tp* pointer;
114 typedef const _Tp* const_pointer;
115 typedef _Tp& reference;
116 typedef const _Tp& const_reference;
117 typedef _Tp value_type;
118
119 template<typename _Tp1>
120 struct rebind
121 { typedef allocator<_Tp1> other; };
122
123 #if __cplusplus >= 201103L
124 // _GLIBCXX_RESOLVE_LIB_DEFECTS
125 // 2103. std::allocator propagate_on_container_move_assignment
126 typedef true_type propagate_on_container_move_assignment;
127
128 typedef true_type is_always_equal;
129 #endif
130
131 allocator() throw() { }
132
133 allocator(const allocator& __a) throw()
134 : __allocator_base<_Tp>(__a) { }
135
136 template<typename _Tp1>
137 allocator(const allocator<_Tp1>&) throw() { }
138
139 ~allocator() throw() { }
140
141 // Inherit everything else.
142 };
143
144 template<typename _T1, typename _T2>
145 inline bool
146 operator==(const allocator<_T1>&, const allocator<_T2>&)
147 _GLIBCXX_USE_NOEXCEPT
148 { return true; }
149
150 template<typename _Tp>
151 inline bool
152 operator==(const allocator<_Tp>&, const allocator<_Tp>&)
153 _GLIBCXX_USE_NOEXCEPT
154 { return true; }
155
156 template<typename _T1, typename _T2>
157 inline bool
158 operator!=(const allocator<_T1>&, const allocator<_T2>&)
159 _GLIBCXX_USE_NOEXCEPT
160 { return false; }
161
162 template<typename _Tp>
163 inline bool
164 operator!=(const allocator<_Tp>&, const allocator<_Tp>&)
165 _GLIBCXX_USE_NOEXCEPT
166 { return false; }
167
168 /// @} group allocator
169
170 // Inhibit implicit instantiations for required instantiations,
171 // which are defined via explicit instantiations elsewhere.
172 #if _GLIBCXX_EXTERN_TEMPLATE
173 extern template class allocator<char>;
174 extern template class allocator<wchar_t>;
175 #endif
176
177 // Undefine.
178 #undef __allocator_base
179
180 // To implement Option 3 of DR 431.
181 template<typename _Alloc, bool = __is_empty(_Alloc)>
182 struct __alloc_swap
183 { static void _S_do_it(_Alloc&, _Alloc&) _GLIBCXX_NOEXCEPT { } };
184
185 template<typename _Alloc>
186 struct __alloc_swap<_Alloc, false>
187 {
188 static void
189 _S_do_it(_Alloc& __one, _Alloc& __two) _GLIBCXX_NOEXCEPT
190 {
191 // Precondition: swappable allocators.
192 if (__one != __two)
193 swap(__one, __two);
194 }
195 };
196
197 // Optimize for stateless allocators.
198 template<typename _Alloc, bool = __is_empty(_Alloc)>
199 struct __alloc_neq
200 {
201 static bool
202 _S_do_it(const _Alloc&, const _Alloc&)
203 { return false; }
204 };
205
206 template<typename _Alloc>
207 struct __alloc_neq<_Alloc, false>
208 {
209 static bool
210 _S_do_it(const _Alloc& __one, const _Alloc& __two)
211 { return __one != __two; }
212 };
213
214 #if __cplusplus >= 201103L
215 template<typename _Tp, bool
216 = __or_<is_copy_constructible<typename _Tp::value_type>,
217 is_nothrow_move_constructible<typename _Tp::value_type>>::value>
218 struct __shrink_to_fit_aux
219 { static bool _S_do_it(_Tp&) noexcept { return false; } };
220
221 template<typename _Tp>
222 struct __shrink_to_fit_aux<_Tp, true>
223 {
224 static bool
225 _S_do_it(_Tp& __c) noexcept
226 {
227 #if __cpp_exceptions
228 try
229 {
230 _Tp(__make_move_if_noexcept_iterator(__c.begin()),
231 __make_move_if_noexcept_iterator(__c.end()),
232 __c.get_allocator()).swap(__c);
233 return true;
234 }
235 catch(...)
236 { return false; }
237 #else
238 return false;
239 #endif
240 }
241 };
242 #endif
243
244 _GLIBCXX_END_NAMESPACE_VERSION
245 } // namespace std
246
247 #endif
248