1 // array allocator -*- C++ -*-
2
3 // Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
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 <bits/c++config.h>
34 #include <new>
35 #include <bits/functexcept.h>
36 #include <tr1/array>
37 #include <bits/move.h>
38
_GLIBCXX_VISIBILITY(default)39 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
40 {
41 _GLIBCXX_BEGIN_NAMESPACE_VERSION
42
43 using std::size_t;
44 using std::ptrdiff_t;
45
46 /// Base class.
47 template<typename _Tp>
48 class array_allocator_base
49 {
50 public:
51 typedef size_t size_type;
52 typedef ptrdiff_t difference_type;
53 typedef _Tp* pointer;
54 typedef const _Tp* const_pointer;
55 typedef _Tp& reference;
56 typedef const _Tp& const_reference;
57 typedef _Tp value_type;
58
59 pointer
60 address(reference __x) const _GLIBCXX_NOEXCEPT
61 { return std::__addressof(__x); }
62
63 const_pointer
64 address(const_reference __x) const _GLIBCXX_NOEXCEPT
65 { return std::__addressof(__x); }
66
67 void
68 deallocate(pointer, size_type)
69 {
70 // Does nothing.
71 }
72
73 size_type
74 max_size() const _GLIBCXX_USE_NOEXCEPT
75 { return size_t(-1) / sizeof(_Tp); }
76
77 #ifdef __GXX_EXPERIMENTAL_CXX0X__
78 template<typename _Up, typename... _Args>
79 void
80 construct(_Up* __p, _Args&&... __args)
81 { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
82
83 template<typename _Up>
84 void
85 destroy(_Up* __p) { __p->~_Up(); }
86 #else
87 // _GLIBCXX_RESOLVE_LIB_DEFECTS
88 // 402. wrong new expression in [some_] allocator::construct
89 void
90 construct(pointer __p, const _Tp& __val)
91 { ::new((void *)__p) value_type(__val); }
92
93 void
94 destroy(pointer __p) { __p->~_Tp(); }
95 #endif
96 };
97
98 /**
99 * @brief An allocator that uses previously allocated memory.
100 * This memory can be externally, globally, or otherwise allocated.
101 * @ingroup allocators
102 */
103 template<typename _Tp, typename _Array = std::tr1::array<_Tp, 1> >
104 class array_allocator : public array_allocator_base<_Tp>
105 {
106 public:
107 typedef size_t size_type;
108 typedef ptrdiff_t difference_type;
109 typedef _Tp* pointer;
110 typedef const _Tp* const_pointer;
111 typedef _Tp& reference;
112 typedef const _Tp& const_reference;
113 typedef _Tp value_type;
114 typedef _Array array_type;
115
116 private:
117 array_type* _M_array;
118 size_type _M_used;
119
120 public:
121 template<typename _Tp1, typename _Array1 = _Array>
122 struct rebind
123 { typedef array_allocator<_Tp1, _Array1> other; };
124
125 array_allocator(array_type* __array = 0) _GLIBCXX_USE_NOEXCEPT
126 : _M_array(__array), _M_used(size_type()) { }
127
128 array_allocator(const array_allocator& __o) _GLIBCXX_USE_NOEXCEPT
129 : _M_array(__o._M_array), _M_used(__o._M_used) { }
130
131 template<typename _Tp1, typename _Array1>
132 array_allocator(const array_allocator<_Tp1, _Array1>&)
133 _GLIBCXX_USE_NOEXCEPT
134 : _M_array(0), _M_used(size_type()) { }
135
136 ~array_allocator() _GLIBCXX_USE_NOEXCEPT { }
137
138 pointer
139 allocate(size_type __n, const void* = 0)
140 {
141 if (_M_array == 0 || _M_used + __n > _M_array->size())
142 std::__throw_bad_alloc();
143 pointer __ret = _M_array->begin() + _M_used;
144 _M_used += __n;
145 return __ret;
146 }
147 };
148
149 template<typename _Tp, typename _Array>
150 inline bool
151 operator==(const array_allocator<_Tp, _Array>&,
152 const array_allocator<_Tp, _Array>&)
153 { return true; }
154
155 template<typename _Tp, typename _Array>
156 inline bool
157 operator!=(const array_allocator<_Tp, _Array>&,
158 const array_allocator<_Tp, _Array>&)
159 { return false; }
160
161 _GLIBCXX_END_NAMESPACE_VERSION
162 } // namespace
163
164 #endif
165