libstdc++

debug_allocator.h
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1 // Allocators -*- 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 /*
26 * Copyright (c) 1996-1997
27 * Silicon Graphics Computer Systems, Inc.
28 *
29 * Permission to use, copy, modify, distribute and sell this software
30 * and its documentation for any purpose is hereby granted without fee,
31 * provided that the above copyright notice appear in all copies and
32 * that both that copyright notice and this permission notice appear
33 * in supporting documentation. Silicon Graphics makes no
34 * representations about the suitability of this software for any
35 * purpose. It is provided "as is" without express or implied warranty.
36 */
37
38 /** @file ext/debug_allocator.h
39 * This file is a GNU extension to the Standard C++ Library.
40 */
41
42 #ifndef _DEBUG_ALLOCATOR_H
43 #define _DEBUG_ALLOCATOR_H 1
44
45 #include <stdexcept>
46
47 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
48 {
49 _GLIBCXX_BEGIN_NAMESPACE_VERSION
50
51 using std::size_t;
52
53 /**
54 * @brief A meta-allocator with debugging bits, as per [20.4].
55 * @ingroup allocators
56 *
57 * This is precisely the allocator defined in the C++ Standard.
58 * - all allocation calls operator new
59 * - all deallocation calls operator delete
60 */
61 template<typename _Alloc>
62 class debug_allocator
63 {
64 public:
65 typedef typename _Alloc::size_type size_type;
66 typedef typename _Alloc::difference_type difference_type;
67 typedef typename _Alloc::pointer pointer;
68 typedef typename _Alloc::const_pointer const_pointer;
69 typedef typename _Alloc::reference reference;
70 typedef typename _Alloc::const_reference const_reference;
71 typedef typename _Alloc::value_type value_type;
72
73 private:
74 // _M_extra is the number of objects that correspond to the
75 // extra space where debug information is stored.
76 size_type _M_extra;
77
78 _Alloc _M_allocator;
79
80 public:
81 debug_allocator()
82 {
83 const size_t __obj_size = sizeof(value_type);
84 _M_extra = (sizeof(size_type) + __obj_size - 1) / __obj_size;
85 }
86
87 pointer
88 allocate(size_type __n)
89 {
90 pointer __res = _M_allocator.allocate(__n + _M_extra);
91 size_type* __ps = reinterpret_cast<size_type*>(__res);
92 *__ps = __n;
93 return __res + _M_extra;
94 }
95
96 pointer
97 allocate(size_type __n, const void* __hint)
98 {
99 pointer __res = _M_allocator.allocate(__n + _M_extra, __hint);
100 size_type* __ps = reinterpret_cast<size_type*>(__res);
101 *__ps = __n;
102 return __res + _M_extra;
103 }
104
105 void
106 deallocate(pointer __p, size_type __n)
107 {
108 if (__p)
109 {
110 pointer __real_p = __p - _M_extra;
111 if (*reinterpret_cast<size_type*>(__real_p) != __n)
112 {
113 throw std::runtime_error("debug_allocator::deallocate"
114 " wrong size");
115 }
116 _M_allocator.deallocate(__real_p, __n + _M_extra);
117 }
118 else
119 throw std::runtime_error("debug_allocator::deallocate null pointer");
120 }
121 };
122
123 _GLIBCXX_END_NAMESPACE_VERSION
124 } // namespace
125
126 #endif