libstdc++

array_allocator.h
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1 // array allocator -*- C++ -*-
2
3 // Copyright (C) 2004-2013 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 /** @file ext/array_allocator.h
26 * This file is a GNU extension to the Standard C++ Library.
27 */
28
29 #ifndef _ARRAY_ALLOCATOR_H
30 #define _ARRAY_ALLOCATOR_H 1
31
32 #include <bits/c++config.h>
33 #include <new>
34 #include <bits/functexcept.h>
35 #include <tr1/array>
36 #include <bits/move.h>
37 #if __cplusplus >= 201103L
38 #include <type_traits>
39 #endif
40
41 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
42 {
43 _GLIBCXX_BEGIN_NAMESPACE_VERSION
44
45 using std::size_t;
46 using std::ptrdiff_t;
47
48 /// Base class.
49 template<typename _Tp>
50 class array_allocator_base
51 {
52 public:
53 typedef size_t size_type;
54 typedef ptrdiff_t difference_type;
55 typedef _Tp* pointer;
56 typedef const _Tp* const_pointer;
57 typedef _Tp& reference;
58 typedef const _Tp& const_reference;
59 typedef _Tp value_type;
60
61 pointer
62 address(reference __x) const _GLIBCXX_NOEXCEPT
63 { return std::__addressof(__x); }
64
65 const_pointer
66 address(const_reference __x) const _GLIBCXX_NOEXCEPT
67 { return std::__addressof(__x); }
68
69 void
70 deallocate(pointer, size_type)
71 {
72 // Does nothing.
73 }
74
75 size_type
76 max_size() const _GLIBCXX_USE_NOEXCEPT
77 { return size_t(-1) / sizeof(_Tp); }
78
79 #if __cplusplus >= 201103L
80 template<typename _Up, typename... _Args>
81 void
82 construct(_Up* __p, _Args&&... __args)
83 { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
84
85 template<typename _Up>
86 void
87 destroy(_Up* __p) { __p->~_Up(); }
88 #else
89 // _GLIBCXX_RESOLVE_LIB_DEFECTS
90 // 402. wrong new expression in [some_] allocator::construct
91 void
92 construct(pointer __p, const _Tp& __val)
93 { ::new((void *)__p) value_type(__val); }
94
95 void
96 destroy(pointer __p) { __p->~_Tp(); }
97 #endif
98 };
99
100 /**
101 * @brief An allocator that uses previously allocated memory.
102 * This memory can be externally, globally, or otherwise allocated.
103 * @ingroup allocators
104 */
105 template<typename _Tp, typename _Array = std::tr1::array<_Tp, 1> >
106 class array_allocator : public array_allocator_base<_Tp>
107 {
108 public:
109 typedef size_t size_type;
110 typedef ptrdiff_t difference_type;
111 typedef _Tp* pointer;
112 typedef const _Tp* const_pointer;
113 typedef _Tp& reference;
114 typedef const _Tp& const_reference;
115 typedef _Tp value_type;
116 typedef _Array array_type;
117
118 #if __cplusplus >= 201103L
119 // _GLIBCXX_RESOLVE_LIB_DEFECTS
120 // 2103. std::allocator propagate_on_container_move_assignment
121 typedef std::true_type propagate_on_container_move_assignment;
122 #endif
123
124 private:
125 array_type* _M_array;
126 size_type _M_used;
127
128 public:
129 template<typename _Tp1, typename _Array1 = _Array>
130 struct rebind
131 { typedef array_allocator<_Tp1, _Array1> other; };
132
133 array_allocator(array_type* __array = 0) _GLIBCXX_USE_NOEXCEPT
134 : _M_array(__array), _M_used(size_type()) { }
135
136 array_allocator(const array_allocator& __o) _GLIBCXX_USE_NOEXCEPT
137 : _M_array(__o._M_array), _M_used(__o._M_used) { }
138
139 template<typename _Tp1, typename _Array1>
140 array_allocator(const array_allocator<_Tp1, _Array1>&)
141 _GLIBCXX_USE_NOEXCEPT
142 : _M_array(0), _M_used(size_type()) { }
143
144 ~array_allocator() _GLIBCXX_USE_NOEXCEPT { }
145
146 pointer
147 allocate(size_type __n, const void* = 0)
148 {
149 if (_M_array == 0 || _M_used + __n > _M_array->size())
150 std::__throw_bad_alloc();
151 pointer __ret = _M_array->begin() + _M_used;
152 _M_used += __n;
153 return __ret;
154 }
155 };
156
157 template<typename _Tp, typename _Array>
158 inline bool
159 operator==(const array_allocator<_Tp, _Array>&,
160 const array_allocator<_Tp, _Array>&)
161 { return true; }
162
163 template<typename _Tp, typename _Array>
164 inline bool
165 operator!=(const array_allocator<_Tp, _Array>&,
166 const array_allocator<_Tp, _Array>&)
167 { return false; }
168
169 _GLIBCXX_END_NAMESPACE_VERSION
170 } // namespace
171
172 #endif