mingw/lib/gcc/mingw32/4.3.3/include/c++/ext/debug_allocator.h

   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