1 // Allocators -*- C++ -*-
2
3 // Copyright (C) 2001-2013 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 namespace std _GLIBCXX_VISIBILITY(default)
53 {
54 _GLIBCXX_BEGIN_NAMESPACE_VERSION
55
56 /**
57 * @addtogroup allocators
58 * @{
59 */
60
61 /// allocator<void> specialization.
62 template<>
63 class allocator<void>
64 {
65 public:
66 typedef size_t size_type;
67 typedef ptrdiff_t difference_type;
68 typedef void* pointer;
69 typedef const void* const_pointer;
70 typedef void value_type;
71
72 template<typename _Tp1>
73 struct rebind
74 { typedef allocator<_Tp1> other; };
75
76 #if __cplusplus >= 201103L
77 // _GLIBCXX_RESOLVE_LIB_DEFECTS
78 // 2103. std::allocator propagate_on_container_move_assignment
79 typedef true_type propagate_on_container_move_assignment;
80 #endif
81 };
82
83 /**
84 * @brief The @a standard allocator, as per [20.4].
85 *
86 * See http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt04ch11.html
87 * for further details.
88 *
89 * @tparam _Tp Type of allocated object.
90 */
91 template<typename _Tp>
92 class allocator: public __allocator_base<_Tp>
93 {
94 public:
95 typedef size_t size_type;
96 typedef ptrdiff_t difference_type;
97 typedef _Tp* pointer;
98 typedef const _Tp* const_pointer;
99 typedef _Tp& reference;
100 typedef const _Tp& const_reference;
101 typedef _Tp value_type;
102
103 template<typename _Tp1>
104 struct rebind
105 { typedef allocator<_Tp1> other; };
106
107 #if __cplusplus >= 201103L
108 // _GLIBCXX_RESOLVE_LIB_DEFECTS
109 // 2103. std::allocator propagate_on_container_move_assignment
110 typedef true_type propagate_on_container_move_assignment;
111 #endif
112
113 allocator() throw() { }
114
115 allocator(const allocator& __a) throw()
116 : __allocator_base<_Tp>(__a) { }
117
118 template<typename _Tp1>
119 allocator(const allocator<_Tp1>&) throw() { }
120
121 ~allocator() throw() { }
122
123 // Inherit everything else.
124 };
125
126 template<typename _T1, typename _T2>
127 inline bool
128 operator==(const allocator<_T1>&, const allocator<_T2>&)
129 { return true; }
130
131 template<typename _Tp>
132 inline bool
133 operator==(const allocator<_Tp>&, const allocator<_Tp>&)
134 { return true; }
135
136 template<typename _T1, typename _T2>
137 inline bool
138 operator!=(const allocator<_T1>&, const allocator<_T2>&)
139 { return false; }
140
141 template<typename _Tp>
142 inline bool
143 operator!=(const allocator<_Tp>&, const allocator<_Tp>&)
144 { return false; }
145
146 /// @} group allocator
147
148 // Inhibit implicit instantiations for required instantiations,
149 // which are defined via explicit instantiations elsewhere.
150 #if _GLIBCXX_EXTERN_TEMPLATE
151 extern template class allocator<char>;
152 extern template class allocator<wchar_t>;
153 #endif
154
155 // Undefine.
156 #undef __allocator_base
157
158 // To implement Option 3 of DR 431.
159 template<typename _Alloc, bool = __is_empty(_Alloc)>
160 struct __alloc_swap
161 { static void _S_do_it(_Alloc&, _Alloc&) { } };
162
163 template<typename _Alloc>
164 struct __alloc_swap<_Alloc, false>
165 {
166 static void
167 _S_do_it(_Alloc& __one, _Alloc& __two)
168 {
169 // Precondition: swappable allocators.
170 if (__one != __two)
171 swap(__one, __two);
172 }
173 };
174
175 // Optimize for stateless allocators.
176 template<typename _Alloc, bool = __is_empty(_Alloc)>
177 struct __alloc_neq
178 {
179 static bool
180 _S_do_it(const _Alloc&, const _Alloc&)
181 { return false; }
182 };
183
184 template<typename _Alloc>
185 struct __alloc_neq<_Alloc, false>
186 {
187 static bool
188 _S_do_it(const _Alloc& __one, const _Alloc& __two)
189 { return __one != __two; }
190 };
191
192 #if __cplusplus >= 201103L
193 template<typename _Tp, bool
194 = __or_<is_copy_constructible<typename _Tp::value_type>,
195 is_nothrow_move_constructible<typename _Tp::value_type>>::value>
196 struct __shrink_to_fit_aux
197 { static bool _S_do_it(_Tp&) { return false; } };
198
199 template<typename _Tp>
200 struct __shrink_to_fit_aux<_Tp, true>
201 {
202 static bool
203 _S_do_it(_Tp& __c)
204 {
205 __try
206 {
207 _Tp(__make_move_if_noexcept_iterator(__c.begin()),
208 __make_move_if_noexcept_iterator(__c.end()),
209 __c.get_allocator()).swap(__c);
210 return true;
211 }
212 __catch(...)
213 { return false; }
214 }
215 };
216 #endif
217
218 _GLIBCXX_END_NAMESPACE_VERSION
219 } // namespace std
220
221 #endif
222