1// Allocators -*- C++ -*-
2
3// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
4// 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 allocator.h
40 *  This is an internal header file, included by other library headers.
41 *  You should not attempt to use it directly.
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_GLIBCXX_BEGIN_NAMESPACE(std)
51
52  /**
53   * @defgroup allocators Allocators
54   * @ingroup memory
55   *
56   * Classes encapsulating memory operations.
57   */
58
59  template<typename _Tp>
60    class allocator;
61
62  /// allocator<void> specialization.
63  template<>
64    class allocator<void>
65    {
66    public:
67      typedef size_t      size_type;
68      typedef ptrdiff_t   difference_type;
69      typedef void*       pointer;
70      typedef const void* const_pointer;
71      typedef void        value_type;
72
73      template<typename _Tp1>
74        struct rebind
75        { typedef allocator<_Tp1> other; };
76    };
77
78  /**
79   * @brief  The "standard" allocator, as per [20.4].
80   * @ingroup allocators
81   *
82   *  Further details:
83   *  http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt04ch11.html
84   */
85  template<typename _Tp>
86    class allocator: public __glibcxx_base_allocator<_Tp>
87    {
88   public:
89      typedef size_t     size_type;
90      typedef ptrdiff_t  difference_type;
91      typedef _Tp*       pointer;
92      typedef const _Tp* const_pointer;
93      typedef _Tp&       reference;
94      typedef const _Tp& const_reference;
95      typedef _Tp        value_type;
96
97      template<typename _Tp1>
98        struct rebind
99        { typedef allocator<_Tp1> other; };
100
101      allocator() throw() { }
102
103      allocator(const allocator& __a) throw()
104      : __glibcxx_base_allocator<_Tp>(__a) { }
105
106      template<typename _Tp1>
107        allocator(const allocator<_Tp1>&) throw() { }
108
109      ~allocator() throw() { }
110
111      // Inherit everything else.
112    };
113
114  template<typename _T1, typename _T2>
115    inline bool
116    operator==(const allocator<_T1>&, const allocator<_T2>&)
117    { return true; }
118
119  template<typename _Tp>
120    inline bool
121    operator==(const allocator<_Tp>&, const allocator<_Tp>&)
122    { return true; }
123
124  template<typename _T1, typename _T2>
125    inline bool
126    operator!=(const allocator<_T1>&, const allocator<_T2>&)
127    { return false; }
128
129  template<typename _Tp>
130    inline bool
131    operator!=(const allocator<_Tp>&, const allocator<_Tp>&)
132    { return false; }
133
134  // Inhibit implicit instantiations for required instantiations,
135  // which are defined via explicit instantiations elsewhere.
136  // NB: This syntax is a GNU extension.
137#if _GLIBCXX_EXTERN_TEMPLATE
138  extern template class allocator<char>;
139  extern template class allocator<wchar_t>;
140#endif
141
142  // Undefine.
143#undef __glibcxx_base_allocator
144
145  // To implement Option 3 of DR 431.
146  template<typename _Alloc, bool = __is_empty(_Alloc)>
147    struct __alloc_swap
148    { static void _S_do_it(_Alloc&, _Alloc&) { } };
149
150  template<typename _Alloc>
151    struct __alloc_swap<_Alloc, false>
152    {
153      static void
154      _S_do_it(_Alloc& __one, _Alloc& __two)
155      {
156	// Precondition: swappable allocators.
157	if (__one != __two)
158	  swap(__one, __two);
159      }
160    };
161
162  // Optimize for stateless allocators.
163  template<typename _Alloc, bool = __is_empty(_Alloc)>
164    struct __alloc_neq
165    {
166      static bool
167      _S_do_it(const _Alloc&, const _Alloc&)
168      { return false; }
169    };
170
171  template<typename _Alloc>
172    struct __alloc_neq<_Alloc, false>
173    {
174      static bool
175      _S_do_it(const _Alloc& __one, const _Alloc& __two)
176      { return __one != __two; }
177    };
178
179_GLIBCXX_END_NAMESPACE
180
181#endif
182