malloc_allocator.h revision 1.1.1.3 
1// Allocator that wraps "C" malloc -*- C++ -*-
2
3// Copyright (C) 2001-2015 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
40namespace __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
153