libstdc++
allocator.h
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1 // Allocators -*- C++ -*-
2 
3 // Copyright (C) 2001-2014 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&) _GLIBCXX_NOEXCEPT { } };
162 
163  template<typename _Alloc>
164  struct __alloc_swap<_Alloc, false>
165  {
166  static void
167  _S_do_it(_Alloc& __one, _Alloc& __two) _GLIBCXX_NOEXCEPT
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&) noexcept { 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) noexcept
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
ISO C++ entities toplevel namespace is std.
The standard allocator, as per [20.4].
Definition: allocator.h:92
void swap(_Tp &, _Tp &) noexcept(__and_< is_nothrow_move_constructible< _Tp >, is_nothrow_move_assignable< _Tp >>::value)
Swaps two values.
Definition: move.h:166
An allocator that uses global new, as per [20.4].This is precisely the allocator defined in the C++ S...