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// Allocators -*- C++ -*-
// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2009, 2010
// Free Software Foundation, Inc.
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <>.
* Copyright (c) 1996-1997
* Silicon Graphics Computer Systems, Inc.
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation. Silicon Graphics makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
/** @file ext/debug_allocator.h
* This file is a GNU extension to the Standard C++ Library.
#include <stdexcept>
namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
using std::size_t;
* @brief A meta-allocator with debugging bits, as per [20.4].
* @ingroup allocators
* This is precisely the allocator defined in the C++ Standard.
* - all allocation calls operator new
* - all deallocation calls operator delete
template<typename _Alloc>
class debug_allocator
typedef typename _Alloc::size_type size_type;
typedef typename _Alloc::difference_type difference_type;
typedef typename _Alloc::pointer pointer;
typedef typename _Alloc::const_pointer const_pointer;
typedef typename _Alloc::reference reference;
typedef typename _Alloc::const_reference const_reference;
typedef typename _Alloc::value_type value_type;
// _M_extra is the number of objects that correspond to the
// extra space where debug information is stored.
size_type _M_extra;
_Alloc _M_allocator;
const size_t __obj_size = sizeof(value_type);
_M_extra = (sizeof(size_type) + __obj_size - 1) / __obj_size;
allocate(size_type __n)
pointer __res = _M_allocator.allocate(__n + _M_extra);
size_type* __ps = reinterpret_cast<size_type*>(__res);
*__ps = __n;
return __res + _M_extra;
allocate(size_type __n, const void* __hint)
pointer __res = _M_allocator.allocate(__n + _M_extra, __hint);
size_type* __ps = reinterpret_cast<size_type*>(__res);
*__ps = __n;
return __res + _M_extra;
deallocate(pointer __p, size_type __n)
if (__p)
pointer __real_p = __p - _M_extra;
if (*reinterpret_cast<size_type*>(__real_p) != __n)
throw std::runtime_error("debug_allocator::deallocate"
" wrong size");
_M_allocator.deallocate(__real_p, __n + _M_extra);
throw std::runtime_error("debug_allocator::deallocate null pointer");
} // namespace