libstdc++
array_allocator.h
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1 // array allocator -*- C++ -*-
2 
3 // Copyright (C) 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 /** @file ext/array_allocator.h
27  * This file is a GNU extension to the Standard C++ Library.
28  */
29 
30 #ifndef _ARRAY_ALLOCATOR_H
31 #define _ARRAY_ALLOCATOR_H 1
32 
33 #include <cstddef>
34 #include <new>
35 #include <bits/functexcept.h>
36 #include <tr1/array>
37 #include <bits/move.h>
38 
39 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
40 
41  using std::size_t;
42  using std::ptrdiff_t;
43 
44  /// Base class.
45  template<typename _Tp>
47  {
48  public:
49  typedef size_t size_type;
50  typedef ptrdiff_t difference_type;
51  typedef _Tp* pointer;
52  typedef const _Tp* const_pointer;
53  typedef _Tp& reference;
54  typedef const _Tp& const_reference;
55  typedef _Tp value_type;
56 
57  pointer
58  address(reference __x) const { return &__x; }
59 
60  const_pointer
61  address(const_reference __x) const { return &__x; }
62 
63  void
64  deallocate(pointer, size_type)
65  {
66  // Does nothing.
67  }
68 
69  size_type
70  max_size() const throw()
71  { return size_t(-1) / sizeof(_Tp); }
72 
73  // _GLIBCXX_RESOLVE_LIB_DEFECTS
74  // 402. wrong new expression in [some_] allocator::construct
75  void
76  construct(pointer __p, const _Tp& __val)
77  { ::new((void *)__p) value_type(__val); }
78 
79 #ifdef __GXX_EXPERIMENTAL_CXX0X__
80  template<typename... _Args>
81  void
82  construct(pointer __p, _Args&&... __args)
83  { ::new((void *)__p) _Tp(std::forward<_Args>(__args)...); }
84 #endif
85 
86  void
87  destroy(pointer __p) { __p->~_Tp(); }
88  };
89 
90  /**
91  * @brief An allocator that uses previously allocated memory.
92  * This memory can be externally, globally, or otherwise allocated.
93  * @ingroup allocators
94  */
95  template<typename _Tp, typename _Array = std::tr1::array<_Tp, 1> >
97  {
98  public:
99  typedef size_t size_type;
100  typedef ptrdiff_t difference_type;
101  typedef _Tp* pointer;
102  typedef const _Tp* const_pointer;
103  typedef _Tp& reference;
104  typedef const _Tp& const_reference;
105  typedef _Tp value_type;
106  typedef _Array array_type;
107 
108  private:
109  array_type* _M_array;
110  size_type _M_used;
111 
112  public:
113  template<typename _Tp1, typename _Array1 = _Array>
114  struct rebind
115  { typedef array_allocator<_Tp1, _Array1> other; };
116 
117  array_allocator(array_type* __array = NULL) throw()
118  : _M_array(__array), _M_used(size_type()) { }
119 
120  array_allocator(const array_allocator& __o) throw()
121  : _M_array(__o._M_array), _M_used(__o._M_used) { }
122 
123  template<typename _Tp1, typename _Array1>
125  : _M_array(NULL), _M_used(size_type()) { }
126 
127  ~array_allocator() throw() { }
128 
129  pointer
130  allocate(size_type __n, const void* = 0)
131  {
132  if (_M_array == 0 || _M_used + __n > _M_array->size())
133  std::__throw_bad_alloc();
134  pointer __ret = _M_array->begin() + _M_used;
135  _M_used += __n;
136  return __ret;
137  }
138  };
139 
140  template<typename _Tp, typename _Array>
141  inline bool
142  operator==(const array_allocator<_Tp, _Array>&,
144  { return true; }
145 
146  template<typename _Tp, typename _Array>
147  inline bool
148  operator!=(const array_allocator<_Tp, _Array>&,
149  const array_allocator<_Tp, _Array>&)
150  { return false; }
151 
152 _GLIBCXX_END_NAMESPACE
153 
154 #endif
An allocator that uses previously allocated memory. This memory can be externally, globally, or otherwise allocated.