1 // Allocators -*- C++ -*- 2 3 // Copyright (C) 2001, 2002, 2003, 2004, 2005 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 2, 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 // You should have received a copy of the GNU General Public License along 17 // with this library; see the file COPYING. If not, write to the Free 18 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 19 // USA. 20 21 // As a special exception, you may use this file as part of a free software 22 // library without restriction. Specifically, if other files instantiate 23 // templates or use macros or inline functions from this file, or you compile 24 // this file and link it with other files to produce an executable, this 25 // file does not by itself cause the resulting executable to be covered by 26 // the GNU General Public License. This exception does not however 27 // invalidate any other reasons why the executable file might be covered by 28 // the GNU General Public License. 29 30 /* 31 * Copyright (c) 1996-1997 32 * Silicon Graphics Computer Systems, Inc. 33 * 34 * Permission to use, copy, modify, distribute and sell this software 35 * and its documentation for any purpose is hereby granted without fee, 36 * provided that the above copyright notice appear in all copies and 37 * that both that copyright notice and this permission notice appear 38 * in supporting documentation. Silicon Graphics makes no 39 * representations about the suitability of this software for any 40 * purpose. It is provided "as is" without express or implied warranty. 41 */ 42 43 /** @file ext/debug_allocator.h 44 * This file is a GNU extension to the Standard C++ Library. 45 * You should only include this header if you are using GCC 3 or later. 46 */ 47 48 #ifndef _DEBUG_ALLOCATOR_H 49 #define _DEBUG_ALLOCATOR_H 1 50 51 #include <stdexcept> 52 53 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx) 54 55 using std::size_t; 56 57 /** 58 * @brief A meta-allocator with debugging bits, as per [20.4]. 59 * 60 * This is precisely the allocator defined in the C++ Standard. 61 * - all allocation calls operator new 62 * - all deallocation calls operator delete 63 */ 64 template<typename _Alloc> 65 class debug_allocator 66 { 67 public: 68 typedef typename _Alloc::size_type size_type; 69 typedef typename _Alloc::difference_type difference_type; 70 typedef typename _Alloc::pointer pointer; 71 typedef typename _Alloc::const_pointer const_pointer; 72 typedef typename _Alloc::reference reference; 73 typedef typename _Alloc::const_reference const_reference; 74 typedef typename _Alloc::value_type value_type; 75 76 private: 77 // _M_extra is the number of objects that correspond to the 78 // extra space where debug information is stored. 79 size_type _M_extra; 80 81 _Alloc _M_allocator; 82 83 public: 84 debug_allocator() 85 { 86 const size_t __obj_size = sizeof(value_type); 87 _M_extra = (sizeof(size_type) + __obj_size - 1) / __obj_size; 88 } 89 90 pointer 91 allocate(size_type __n) 92 { 93 pointer __res = _M_allocator.allocate(__n + _M_extra); 94 size_type* __ps = reinterpret_cast<size_type*>(__res); 95 *__ps = __n; 96 return __res + _M_extra; 97 } 98 99 pointer 100 allocate(size_type __n, const void* __hint) 101 { 102 pointer __res = _M_allocator.allocate(__n + _M_extra, __hint); 103 size_type* __ps = reinterpret_cast<size_type*>(__res); 104 *__ps = __n; 105 return __res + _M_extra; 106 } 107 108 void 109 deallocate(pointer __p, size_type __n) 110 { 111 if (__p) 112 { 113 pointer __real_p = __p - _M_extra; 114 if (*reinterpret_cast<size_type*>(__real_p) != __n) 115 { 116 throw std::runtime_error("debug_allocator::deallocate" 117 " wrong size"); 118 } 119 _M_allocator.deallocate(__real_p, __n + _M_extra); 120 } 121 else 122 throw std::runtime_error("debug_allocator::deallocate null pointer"); 123 } 124 }; 125 126 _GLIBCXX_END_NAMESPACE 127 128 #endif 129