1 // Allocators -*- C++ -*- 2 3 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2009, 2010 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 /* 27 * Copyright (c) 1996-1997 28 * Silicon Graphics Computer Systems, Inc. 29 * 30 * Permission to use, copy, modify, distribute and sell this software 31 * and its documentation for any purpose is hereby granted without fee, 32 * provided that the above copyright notice appear in all copies and 33 * that both that copyright notice and this permission notice appear 34 * in supporting documentation. Silicon Graphics makes no 35 * representations about the suitability of this software for any 36 * purpose. It is provided "as is" without express or implied warranty. 37 */ 38 39 /** @file ext/debug_allocator.h 40 * This file is a GNU extension to the Standard C++ Library. 41 */ 42 43 #ifndef _DEBUG_ALLOCATOR_H 44 #define _DEBUG_ALLOCATOR_H 1 45 46 #include <stdexcept> 47 48 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) 49 { 50 _GLIBCXX_BEGIN_NAMESPACE_VERSION 51 52 using std::size_t; 53 54 /** 55 * @brief A meta-allocator with debugging bits, as per [20.4]. 56 * @ingroup allocators 57 * 58 * This is precisely the allocator defined in the C++ Standard. 59 * - all allocation calls operator new 60 * - all deallocation calls operator delete 61 */ 62 template<typename _Alloc> 63 class debug_allocator 64 { 65 public: 66 typedef typename _Alloc::size_type size_type; 67 typedef typename _Alloc::difference_type difference_type; 68 typedef typename _Alloc::pointer pointer; 69 typedef typename _Alloc::const_pointer const_pointer; 70 typedef typename _Alloc::reference reference; 71 typedef typename _Alloc::const_reference const_reference; 72 typedef typename _Alloc::value_type value_type; 73 74 private: 75 // _M_extra is the number of objects that correspond to the 76 // extra space where debug information is stored. 77 size_type _M_extra; 78 79 _Alloc _M_allocator; 80 81 public: 82 debug_allocator() 83 { 84 const size_t __obj_size = sizeof(value_type); 85 _M_extra = (sizeof(size_type) + __obj_size - 1) / __obj_size; 86 } 87 88 pointer 89 allocate(size_type __n) 90 { 91 pointer __res = _M_allocator.allocate(__n + _M_extra); 92 size_type* __ps = reinterpret_cast<size_type*>(__res); 93 *__ps = __n; 94 return __res + _M_extra; 95 } 96 97 pointer 98 allocate(size_type __n, const void* __hint) 99 { 100 pointer __res = _M_allocator.allocate(__n + _M_extra, __hint); 101 size_type* __ps = reinterpret_cast<size_type*>(__res); 102 *__ps = __n; 103 return __res + _M_extra; 104 } 105 106 void 107 deallocate(pointer __p, size_type __n) 108 { 109 if (__p) 110 { 111 pointer __real_p = __p - _M_extra; 112 if (*reinterpret_cast<size_type*>(__real_p) != __n) 113 { 114 throw std::runtime_error("debug_allocator::deallocate" 115 " wrong size"); 116 } 117 _M_allocator.deallocate(__real_p, __n + _M_extra); 118 } 119 else 120 throw std::runtime_error("debug_allocator::deallocate null pointer"); 121 } 122 }; 123 124 _GLIBCXX_END_NAMESPACE_VERSION 125 } // namespace 126 127 #endif 128