1// Allocators -*- C++ -*-
2
3// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006
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 2, 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// You should have received a copy of the GNU General Public License along
18// with this library; see the file COPYING.  If not, write to the Free
19// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
20// USA.
21
22// As a special exception, you may use this file as part of a free software
23// library without restriction.  Specifically, if other files instantiate
24// templates or use macros or inline functions from this file, or you compile
25// this file and link it with other files to produce an executable, this
26// file does not by itself cause the resulting executable to be covered by
27// the GNU General Public License.  This exception does not however
28// invalidate any other reasons why the executable file might be covered by
29// the GNU General Public License.
30
31/*
32 * Copyright (c) 1996-1997
33 * Silicon Graphics Computer Systems, Inc.
34 *
35 * Permission to use, copy, modify, distribute and sell this software
36 * and its documentation for any purpose is hereby granted without fee,
37 * provided that the above copyright notice appear in all copies and
38 * that both that copyright notice and this permission notice appear
39 * in supporting documentation.  Silicon Graphics makes no
40 * representations about the suitability of this software for any
41 * purpose.  It is provided "as is" without express or implied warranty.
42 */
43
44/** @file allocator.h
45 *  This is an internal header file, included by other library headers.
46 *  You should not attempt to use it directly.
47 */
48
49#ifndef _ALLOCATOR_H
50#define _ALLOCATOR_H 1
51
52// Define the base class to std::allocator.
53#include <bits/c++allocator.h>
54
55#include <bits/cpp_type_traits.h> // for __is_empty
56
57_GLIBCXX_BEGIN_NAMESPACE(std)
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   *
81   *  Further details:
82   *  http://gcc.gnu.org/onlinedocs/libstdc++/20_util/allocator.html
83   */
84  template<typename _Tp>
85    class allocator: public __glibcxx_base_allocator<_Tp>
86    {
87   public:
88      typedef size_t     size_type;
89      typedef ptrdiff_t  difference_type;
90      typedef _Tp*       pointer;
91      typedef const _Tp* const_pointer;
92      typedef _Tp&       reference;
93      typedef const _Tp& const_reference;
94      typedef _Tp        value_type;
95
96      template<typename _Tp1>
97        struct rebind
98        { typedef allocator<_Tp1> other; };
99
100      allocator() throw() { }
101
102      allocator(const allocator& __a) throw()
103      : __glibcxx_base_allocator<_Tp>(__a) { }
104
105      template<typename _Tp1>
106        allocator(const allocator<_Tp1>&) throw() { }
107
108      ~allocator() throw() { }
109
110      // Inherit everything else.
111    };
112
113  template<typename _T1, typename _T2>
114    inline bool
115    operator==(const allocator<_T1>&, const allocator<_T2>&)
116    { return true; }
117
118  template<typename _Tp>
119    inline bool
120    operator==(const allocator<_Tp>&, const allocator<_Tp>&)
121    { return true; }
122
123  template<typename _T1, typename _T2>
124    inline bool
125    operator!=(const allocator<_T1>&, const allocator<_T2>&)
126    { return false; }
127
128  template<typename _Tp>
129    inline bool
130    operator!=(const allocator<_Tp>&, const allocator<_Tp>&)
131    { return false; }
132
133  // Inhibit implicit instantiations for required instantiations,
134  // which are defined via explicit instantiations elsewhere.
135  // NB: This syntax is a GNU extension.
136#if _GLIBCXX_EXTERN_TEMPLATE
137  extern template class allocator<char>;
138  extern template class allocator<wchar_t>;
139#endif
140
141  // Undefine.
142#undef __glibcxx_base_allocator
143
144  // To implement Option 3 of DR 431.
145  template<typename _Alloc, bool = std::__is_empty<_Alloc>::__value>
146    struct __alloc_swap
147    { static void _S_do_it(_Alloc&, _Alloc&) { } };
148
149  template<typename _Alloc>
150    struct __alloc_swap<_Alloc, false>
151    {
152      static void
153      _S_do_it(_Alloc& __one, _Alloc& __two)
154      {
155	// Precondition: swappable allocators.
156	if (__one != __two)
157	  swap(__one, __two);
158      }
159    };
160
161_GLIBCXX_END_NAMESPACE
162
163#endif
164