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 127
