libstdc++

malloc_allocator.h
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1 // Allocator that wraps "C" malloc -*- C++ -*-
2
3 // Copyright (C) 2001-2013 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/malloc_allocator.h
26 * This file is a GNU extension to the Standard C++ Library.
27 */
28
29 #ifndef _MALLOC_ALLOCATOR_H
30 #define _MALLOC_ALLOCATOR_H 1
31
32 #include <cstdlib>
33 #include <new>
34 #include <bits/functexcept.h>
35 #include <bits/move.h>
36 #if __cplusplus >= 201103L
37 #include <type_traits>
38 #endif
39
40 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
41 {
42 _GLIBCXX_BEGIN_NAMESPACE_VERSION
43
44 using std::size_t;
45 using std::ptrdiff_t;
46
47 /**
48 * @brief An allocator that uses malloc.
49 * @ingroup allocators
50 *
51 * This is precisely the allocator defined in the C++ Standard.
52 * - all allocation calls malloc
53 * - all deallocation calls free
54 */
55 template<typename _Tp>
56 class malloc_allocator
57 {
58 public:
59 typedef size_t size_type;
60 typedef ptrdiff_t difference_type;
61 typedef _Tp* pointer;
62 typedef const _Tp* const_pointer;
63 typedef _Tp& reference;
64 typedef const _Tp& const_reference;
65 typedef _Tp value_type;
66
67 template<typename _Tp1>
68 struct rebind
69 { typedef malloc_allocator<_Tp1> other; };
70
71 #if __cplusplus >= 201103L
72 // _GLIBCXX_RESOLVE_LIB_DEFECTS
73 // 2103. propagate_on_container_move_assignment
74 typedef std::true_type propagate_on_container_move_assignment;
75 #endif
76
77 malloc_allocator() _GLIBCXX_USE_NOEXCEPT { }
78
79 malloc_allocator(const malloc_allocator&) _GLIBCXX_USE_NOEXCEPT { }
80
81 template<typename _Tp1>
82 malloc_allocator(const malloc_allocator<_Tp1>&)
83 _GLIBCXX_USE_NOEXCEPT { }
84
85 ~malloc_allocator() _GLIBCXX_USE_NOEXCEPT { }
86
87 pointer
88 address(reference __x) const _GLIBCXX_NOEXCEPT
89 { return std::__addressof(__x); }
90
91 const_pointer
92 address(const_reference __x) const _GLIBCXX_NOEXCEPT
93 { return std::__addressof(__x); }
94
95 // NB: __n is permitted to be 0. The C++ standard says nothing
96 // about what the return value is when __n == 0.
97 pointer
98 allocate(size_type __n, const void* = 0)
99 {
100 if (__n > this->max_size())
101 std::__throw_bad_alloc();
102
103 pointer __ret = static_cast<_Tp*>(std::malloc(__n * sizeof(_Tp)));
104 if (!__ret)
105 std::__throw_bad_alloc();
106 return __ret;
107 }
108
109 // __p is not permitted to be a null pointer.
110 void
111 deallocate(pointer __p, size_type)
112 { std::free(static_cast<void*>(__p)); }
113
114 size_type
115 max_size() const _GLIBCXX_USE_NOEXCEPT
116 { return size_t(-1) / sizeof(_Tp); }
117
118 #if __cplusplus >= 201103L
119 template<typename _Up, typename... _Args>
120 void
121 construct(_Up* __p, _Args&&... __args)
122 { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
123
124 template<typename _Up>
125 void
126 destroy(_Up* __p) { __p->~_Up(); }
127 #else
128 // _GLIBCXX_RESOLVE_LIB_DEFECTS
129 // 402. wrong new expression in [some_] allocator::construct
130 void
131 construct(pointer __p, const _Tp& __val)
132 { ::new((void *)__p) value_type(__val); }
133
134 void
135 destroy(pointer __p) { __p->~_Tp(); }
136 #endif
137 };
138
139 template<typename _Tp>
140 inline bool
141 operator==(const malloc_allocator<_Tp>&, const malloc_allocator<_Tp>&)
142 { return true; }
143
144 template<typename _Tp>
145 inline bool
146 operator!=(const malloc_allocator<_Tp>&, const malloc_allocator<_Tp>&)
147 { return false; }
148
149 _GLIBCXX_END_NAMESPACE_VERSION
150 } // namespace
151
152 #endif