00001 // Allocators -*- C++ -*- 00002 00003 // Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc. 00004 // 00005 // This file is part of the GNU ISO C++ Library. This library is free 00006 // software; you can redistribute it and/or modify it under the 00007 // terms of the GNU General Public License as published by the 00008 // Free Software Foundation; either version 2, or (at your option) 00009 // any later version. 00010 00011 // This library is distributed in the hope that it will be useful, 00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00014 // GNU General Public License for more details. 00015 00016 // You should have received a copy of the GNU General Public License along 00017 // with this library; see the file COPYING. If not, write to the Free 00018 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 00019 // USA. 00020 00021 // As a special exception, you may use this file as part of a free software 00022 // library without restriction. Specifically, if other files instantiate 00023 // templates or use macros or inline functions from this file, or you compile 00024 // this file and link it with other files to produce an executable, this 00025 // file does not by itself cause the resulting executable to be covered by 00026 // the GNU General Public License. This exception does not however 00027 // invalidate any other reasons why the executable file might be covered by 00028 // the GNU General Public License. 00029 00030 /* 00031 * Copyright (c) 1996-1997 00032 * Silicon Graphics Computer Systems, Inc. 00033 * 00034 * Permission to use, copy, modify, distribute and sell this software 00035 * and its documentation for any purpose is hereby granted without fee, 00036 * provided that the above copyright notice appear in all copies and 00037 * that both that copyright notice and this permission notice appear 00038 * in supporting documentation. Silicon Graphics makes no 00039 * representations about the suitability of this software for any 00040 * purpose. It is provided "as is" without express or implied warranty. 00041 */ 00042 00043 /** @file ext/debug_allocator.h 00044 * This file is a GNU extension to the Standard C++ Library. 00045 * You should only include this header if you are using GCC 3 or later. 00046 */ 00047 00048 #ifndef _DEBUG_ALLOCATOR_H 00049 #define _DEBUG_ALLOCATOR_H 1 00050 00051 #include <stdexcept> 00052 00053 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx) 00054 00055 using std::size_t; 00056 00057 /** 00058 * @brief A meta-allocator with debugging bits, as per [20.4]. 00059 * 00060 * This is precisely the allocator defined in the C++ Standard. 00061 * - all allocation calls operator new 00062 * - all deallocation calls operator delete 00063 */ 00064 template<typename _Alloc> 00065 class debug_allocator 00066 { 00067 public: 00068 typedef typename _Alloc::size_type size_type; 00069 typedef typename _Alloc::difference_type difference_type; 00070 typedef typename _Alloc::pointer pointer; 00071 typedef typename _Alloc::const_pointer const_pointer; 00072 typedef typename _Alloc::reference reference; 00073 typedef typename _Alloc::const_reference const_reference; 00074 typedef typename _Alloc::value_type value_type; 00075 00076 private: 00077 // _M_extra is the number of objects that correspond to the 00078 // extra space where debug information is stored. 00079 size_type _M_extra; 00080 00081 _Alloc _M_allocator; 00082 00083 public: 00084 debug_allocator() 00085 { 00086 const size_t __obj_size = sizeof(value_type); 00087 _M_extra = (sizeof(size_type) + __obj_size - 1) / __obj_size; 00088 } 00089 00090 pointer 00091 allocate(size_type __n) 00092 { 00093 pointer __res = _M_allocator.allocate(__n + _M_extra); 00094 size_type* __ps = reinterpret_cast<size_type*>(__res); 00095 *__ps = __n; 00096 return __res + _M_extra; 00097 } 00098 00099 pointer 00100 allocate(size_type __n, const void* __hint) 00101 { 00102 pointer __res = _M_allocator.allocate(__n + _M_extra, __hint); 00103 size_type* __ps = reinterpret_cast<size_type*>(__res); 00104 *__ps = __n; 00105 return __res + _M_extra; 00106 } 00107 00108 void 00109 deallocate(pointer __p, size_type __n) 00110 { 00111 if (__p) 00112 { 00113 pointer __real_p = __p - _M_extra; 00114 if (*reinterpret_cast<size_type*>(__real_p) != __n) 00115 { 00116 throw std::runtime_error("debug_allocator::deallocate" 00117 " wrong size"); 00118 } 00119 _M_allocator.deallocate(__real_p, __n + _M_extra); 00120 } 00121 else 00122 throw std::runtime_error("debug_allocator::deallocate null pointer"); 00123 } 00124 }; 00125 00126 _GLIBCXX_END_NAMESPACE 00127 00128 #endif