1// Allocators -*- C++ -*-
2
3// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
4// 2011 Free Software Foundation, Inc.
5//
6// This file is part of the GNU ISO C++ Library. This library is free
7// software; you can redistribute it and/or modify it under the
8// terms of the GNU General Public License as published by the
9// Free Software Foundation; either version 3, or (at your option)
10// any later version.
11
12// This library is distributed in the hope that it will be useful,
13// but WITHOUT ANY WARRANTY; without even the implied warranty of
14// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15// GNU General Public License for more details.
16
17// Under Section 7 of GPL version 3, you are granted additional
18// permissions described in the GCC Runtime Library Exception, version
19// 3.1, as published by the Free Software Foundation.
20
21// You should have received a copy of the GNU General Public License and
22// a copy of the GCC Runtime Library Exception along with this program;
23// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
24// <http://www.gnu.org/licenses/>.
25
26/*
27 * Copyright (c) 1996-1997
28 * Silicon Graphics Computer Systems, Inc.
29 *
30 * Permission to use, copy, modify, distribute and sell this software
31 * and its documentation for any purpose is hereby granted without fee,
32 * provided that the above copyright notice appear in all copies and
33 * that both that copyright notice and this permission notice appear
34 * in supporting documentation. Silicon Graphics makes no
35 * representations about the suitability of this software for any
36 * purpose. It is provided "as is" without express or implied warranty.
37 */
38
39/** @file bits/allocator.h
40 * This is an internal header file, included by other library headers.
41 * Do not attempt to use it directly. @headername{memory}
42 */
43
44#ifndef _ALLOCATOR_H
45#define _ALLOCATOR_H 1
46
47// Define the base class to std::allocator.
48#include <bits/c++allocator.h>
49
50namespace std _GLIBCXX_VISIBILITY(default)
51{
52_GLIBCXX_BEGIN_NAMESPACE_VERSION
53
54 /**
55 * @defgroup allocators Allocators
56 * @ingroup memory
57 *
58 * Classes encapsulating memory operations.
59 *
60 * @{
61 */
62
63 template<typename _Tp>
64 class allocator;
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
82 /**
83 * @brief The @a standard allocator, as per [20.4].
84 *
85 * See http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt04ch11.html
86 * for further details.
87 */
88 template<typename _Tp>
89 class allocator: public __glibcxx_base_allocator<_Tp>
90 {
91 public:
92 typedef size_t size_type;
93 typedef ptrdiff_t difference_type;
94 typedef _Tp* pointer;
95 typedef const _Tp* const_pointer;
96 typedef _Tp& reference;
97 typedef const _Tp& const_reference;
98 typedef _Tp value_type;
99
100 template<typename _Tp1>
101 struct rebind
102 { typedef allocator<_Tp1> other; };
103
104 allocator() throw() { }
105
106 allocator(const allocator& __a) throw()
107 : __glibcxx_base_allocator<_Tp>(__a) { }
108
109 template<typename _Tp1>
110 allocator(const allocator<_Tp1>&) throw() { }
111
112 ~allocator() throw() { }
113
114 // Inherit everything else.
115 };
116
117 template<typename _T1, typename _T2>
118 inline bool
119 operator==(const allocator<_T1>&, const allocator<_T2>&)
120 { return true; }
121
122 template<typename _Tp>
123 inline bool
124 operator==(const allocator<_Tp>&, const allocator<_Tp>&)
125 { return true; }
126
127 template<typename _T1, typename _T2>
128 inline bool
129 operator!=(const allocator<_T1>&, const allocator<_T2>&)
130 { return false; }
131
132 template<typename _Tp>
133 inline bool
134 operator!=(const allocator<_Tp>&, const allocator<_Tp>&)
135 { return false; }
136
137 /**
138 * @}
139 */
140
141 // Inhibit implicit instantiations for required instantiations,
142 // which are defined via explicit instantiations elsewhere.
143#if _GLIBCXX_EXTERN_TEMPLATE
144 extern template class allocator<char>;
145 extern template class allocator<wchar_t>;
146#endif
147
148 // Undefine.
149#undef __glibcxx_base_allocator
150
151 // To implement Option 3 of DR 431.
152 template<typename _Alloc, bool = __is_empty(_Alloc)>
153 struct __alloc_swap
154 { static void _S_do_it(_Alloc&, _Alloc&) { } };
155
156 template<typename _Alloc>
157 struct __alloc_swap<_Alloc, false>
158 {
159 static void
160 _S_do_it(_Alloc& __one, _Alloc& __two)
161 {
162 // Precondition: swappable allocators.
163 if (__one != __two)
164 swap(__one, __two);
165 }
166 };
167
168 // Optimize for stateless allocators.
169 template<typename _Alloc, bool = __is_empty(_Alloc)>
170 struct __alloc_neq
171 {
172 static bool
173 _S_do_it(const _Alloc&, const _Alloc&)
174 { return false; }
175 };
176
177 template<typename _Alloc>
178 struct __alloc_neq<_Alloc, false>
179 {
180 static bool
181 _S_do_it(const _Alloc& __one, const _Alloc& __two)
182 { return __one != __two; }
183 };
184
185#ifdef __GXX_EXPERIMENTAL_CXX0X__
186 template<typename _Tp, bool
187 = __or_<is_copy_constructible<typename _Tp::value_type>,
188 is_nothrow_move_constructible<typename _Tp::value_type>>::value>
189 struct __shrink_to_fit_aux
190 { static bool _S_do_it(_Tp&) { return false; } };
191
192 template<typename _Tp>
193 struct __shrink_to_fit_aux<_Tp, true>
194 {
195 static bool
196 _S_do_it(_Tp& __c)
197 {
198 __try
199 {
200 _Tp(__make_move_if_noexcept_iterator(__c.begin()),
201 __make_move_if_noexcept_iterator(__c.end()),
202 __c.get_allocator()).swap(__c);
203 return true;
204 }
205 __catch(...)
206 { return false; }
207 }
208 };
209
210 // Declare uses_allocator so it can be specialized in <queue> etc.
211 template<typename, typename>
212 struct uses_allocator;
213#endif
214
215_GLIBCXX_END_NAMESPACE_VERSION
216} // namespace std
217
218#endif
219