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 :
50 : #ifdef __GXX_EXPERIMENTAL_CXX0X__
51 : #include <type_traits> // For _GLIBCXX_HAS_NESTED_TYPE
52 : #endif
53 :
54 : namespace std _GLIBCXX_VISIBILITY(default)
55 : {
56 : _GLIBCXX_BEGIN_NAMESPACE_VERSION
57 :
58 : /**
59 : * @defgroup allocators Allocators
60 : * @ingroup memory
61 : *
62 : * Classes encapsulating memory operations.
63 : */
64 :
65 : template<typename _Tp>
66 : class allocator;
67 :
68 : /// allocator<void> specialization.
69 : template<>
70 : class allocator<void>
71 : {
72 : public:
73 : typedef size_t size_type;
74 : typedef ptrdiff_t difference_type;
75 : typedef void* pointer;
76 : typedef const void* const_pointer;
77 : typedef void value_type;
78 :
79 : template<typename _Tp1>
80 : struct rebind
81 : { typedef allocator<_Tp1> other; };
82 : };
83 :
84 : /**
85 : * @brief The @a standard allocator, as per [20.4].
86 : * @ingroup allocators
87 : *
88 : * Further details:
89 : * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt04ch11.html
90 : */
91 : template<typename _Tp>
92 : class allocator: public __glibcxx_base_allocator<_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 771414 : allocator() throw() { }
108 :
109 1918 : allocator(const allocator& __a) throw()
110 1918 : : __glibcxx_base_allocator<_Tp>(__a) { }
111 :
112 : template<typename _Tp1>
113 4207 : allocator(const allocator<_Tp1>&) throw() { }
114 :
115 777432 : ~allocator() throw() { }
116 :
117 : // Inherit everything else.
118 : };
119 :
120 : template<typename _T1, typename _T2>
121 : inline bool
122 : operator==(const allocator<_T1>&, const allocator<_T2>&)
123 : { return true; }
124 :
125 : template<typename _Tp>
126 : inline bool
127 0 : operator==(const allocator<_Tp>&, const allocator<_Tp>&)
128 0 : { return true; }
129 :
130 : template<typename _T1, typename _T2>
131 : inline bool
132 : operator!=(const allocator<_T1>&, const allocator<_T2>&)
133 : { return false; }
134 :
135 : template<typename _Tp>
136 : inline bool
137 : operator!=(const allocator<_Tp>&, const allocator<_Tp>&)
138 : { return false; }
139 :
140 : // Inhibit implicit instantiations for required instantiations,
141 : // which are defined via explicit instantiations elsewhere.
142 : #if _GLIBCXX_EXTERN_TEMPLATE
143 : extern template class allocator<char>;
144 : extern template class allocator<wchar_t>;
145 : #endif
146 :
147 : // Undefine.
148 : #undef __glibcxx_base_allocator
149 :
150 : // To implement Option 3 of DR 431.
151 : template<typename _Alloc, bool = __is_empty(_Alloc)>
152 : struct __alloc_swap
153 : { static void _S_do_it(_Alloc&, _Alloc&) { } };
154 :
155 : template<typename _Alloc>
156 : struct __alloc_swap<_Alloc, false>
157 : {
158 : static void
159 : _S_do_it(_Alloc& __one, _Alloc& __two)
160 : {
161 : // Precondition: swappable allocators.
162 : if (__one != __two)
163 : swap(__one, __two);
164 : }
165 : };
166 :
167 : // Optimize for stateless allocators.
168 : template<typename _Alloc, bool = __is_empty(_Alloc)>
169 : struct __alloc_neq
170 : {
171 : static bool
172 : _S_do_it(const _Alloc&, const _Alloc&)
173 : { return false; }
174 : };
175 :
176 : template<typename _Alloc>
177 : struct __alloc_neq<_Alloc, false>
178 : {
179 : static bool
180 : _S_do_it(const _Alloc& __one, const _Alloc& __two)
181 : { return __one != __two; }
182 : };
183 :
184 : #ifdef __GXX_EXPERIMENTAL_CXX0X__
185 : // A very basic implementation for now. In general we have to wait for
186 : // the availability of the infrastructure described in N2983: we should
187 : // try when either T has a move constructor which cannot throw or T is
188 : // CopyContructible.
189 : // NB: This code doesn't properly belong here, we should find a more
190 : // suited place common to std::vector and std::deque.
191 : template<typename _Tp,
192 : bool = __has_trivial_copy(typename _Tp::value_type)>
193 : struct __shrink_to_fit
194 : { static void _S_do_it(_Tp&) { } };
195 :
196 : template<typename _Tp>
197 : struct __shrink_to_fit<_Tp, true>
198 : {
199 : static void
200 : _S_do_it(_Tp& __v)
201 : {
202 : __try
203 : { _Tp(__v).swap(__v); }
204 : __catch(...) { }
205 : }
206 : };
207 :
208 :
209 : /// [allocator.tag]
210 : struct allocator_arg_t { };
211 :
212 : constexpr allocator_arg_t allocator_arg = allocator_arg_t();
213 :
214 : _GLIBCXX_HAS_NESTED_TYPE(allocator_type)
215 :
216 : template<typename _Tp, typename _Alloc,
217 : bool = __has_allocator_type<_Tp>::value>
218 : struct __uses_allocator_helper
219 : : public false_type { };
220 :
221 : template<typename _Tp, typename _Alloc>
222 : struct __uses_allocator_helper<_Tp, _Alloc, true>
223 : : public integral_constant<bool, is_convertible<_Alloc,
224 : typename _Tp::allocator_type>::value>
225 : { };
226 :
227 : /// [allocator.uses.trait]
228 : template<typename _Tp, typename _Alloc>
229 : struct uses_allocator
230 : : public integral_constant<bool,
231 : __uses_allocator_helper<_Tp, _Alloc>::value>
232 : { };
233 :
234 : #endif
235 :
236 : _GLIBCXX_END_NAMESPACE_VERSION
237 : } // namespace std
238 :
239 : #endif
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