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The C and C++ Include Header Files

/usr/include/c++/13/ext/debug_allocator.h


$ cat -n /usr/include/c++/13/ext/debug_allocator.h

     1	// Allocators -*- C++ -*-
     2	
     3	// Copyright (C) 2001-2023 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 <bits/requires_hosted.h> // GNU extensions are currently omitted
    46	
    47	#include <stdexcept>
    48	#include <bits/functexcept.h>
    49	#include <ext/alloc_traits.h>
    50	
    51	namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
    52	{
    53	_GLIBCXX_BEGIN_NAMESPACE_VERSION
    54	
    55	  /**
    56	   *  @brief  A meta-allocator with debugging bits.
    57	   *  @ingroup allocators
    58	   *
    59	   *  This is precisely the allocator defined in the C++03 Standard.
    60	   */
    61	  template<typename _Alloc>
    62	    class debug_allocator
    63	    {
    64	      template<typename> friend class debug_allocator;
    65	
    66	      typedef __alloc_traits<_Alloc> _Traits;
    67	
    68	    public:
    69	      typedef typename _Traits::size_type       	size_type;
    70	      typedef typename _Traits::difference_type	difference_type;
    71	      typedef typename _Traits::pointer       	pointer;
    72	      typedef typename _Traits::const_pointer    const_pointer;
    73	      typedef typename _Traits::reference       	reference;
    74	      typedef typename _Traits::const_reference  const_reference;
    75	      typedef typename _Traits::value_type       value_type;
    76	
    77	      template<typename _Up>
    78		class rebind
    79		{
    80		  typedef typename _Traits::template rebind<_Up>::other __other;
    81	
    82		public:
    83		  typedef debug_allocator<__other> other;
    84		};
    85	
    86	    private:
    87	      // _M_extra is the number of objects that correspond to the
    88	      // extra space where debug information is stored.
    89	      size_type 		_M_extra;
    90	      
    91	      _Alloc			_M_allocator;
    92	
    93	      template<typename _Alloc2,
    94		       typename = typename __alloc_traits<_Alloc2>::template
    95				   rebind<value_type>::other>
    96		struct __convertible
    97		{ };
    98	
    99	      template<typename _Alloc2>
   100		struct __convertible<_Alloc2, _Alloc>
   101		{
   102		  typedef void* __type;
   103		};
   104	
   105	      size_type _S_extra()
   106	      {
   107		const std::size_t __obj_size = sizeof(value_type);
   108		return (sizeof(size_type) + __obj_size - 1) / __obj_size; 
   109	      }
   110	
   111	    public:
   112	      debug_allocator() : _M_extra(_S_extra()) { }
   113	
   114	      template<typename _Alloc2>
   115		debug_allocator(const debug_allocator<_Alloc2>& __a2,
   116				typename __convertible<_Alloc2>::__type = 0)
   117		: _M_extra(_S_extra()), _M_allocator(__a2._M_allocator)  { }
   118	
   119	      debug_allocator(const _Alloc& __a)
   120	      : _M_extra(_S_extra()), _M_allocator(__a)  { }
   121	
   122	      _GLIBCXX_NODISCARD pointer
   123	      allocate(size_type __n)
   124	      {
   125	        pointer __res = _M_allocator.allocate(__n + _M_extra);      
   126		size_type* __ps = reinterpret_cast<size_type*>(__res);
   127		*__ps = __n;
   128	        return __res + _M_extra;
   129	      }
   130	
   131	      _GLIBCXX_NODISCARD pointer
   132	      allocate(size_type __n, const void* __hint)
   133	      {
   134	        pointer __res = _M_allocator.allocate(__n + _M_extra, __hint);
   135		size_type* __ps = reinterpret_cast<size_type*>(__res);
   136		*__ps = __n;
   137	        return __res + _M_extra;
   138	      }
   139	
   140	      void
   141	      deallocate(pointer __p, size_type __n)
   142	      {
   143		using std::__throw_runtime_error;
   144		if (__p)
   145		  {
   146		    pointer __real_p = __p - _M_extra;
   147		    if (*reinterpret_cast<size_type*>(__real_p) != __n)
   148		      __throw_runtime_error("debug_allocator::deallocate wrong size");
   149		    _M_allocator.deallocate(__real_p, __n + _M_extra);
   150		  }
   151		else
   152		  __throw_runtime_error("debug_allocator::deallocate null pointer");
   153	      }
   154	
   155	      void
   156	      construct(pointer __p, const value_type& __val)
   157	      { _Traits::construct(_M_allocator, __p, __val); }
   158	
   159	#if __cplusplus >= 201103L
   160	      template<typename _Tp, typename... _Args>
   161		void
   162		construct(_Tp* __p, _Args&&... __args)
   163		{
   164		  _Traits::construct(_M_allocator, __p,
   165				     std::forward<_Args>(__args)...);
   166		}
   167	#endif
   168	
   169	      template<typename _Tp>
   170		void
   171		destroy(_Tp* __p)
   172		{ _Traits::destroy(_M_allocator, __p); }
   173	
   174	      size_type
   175	      max_size() const throw()
   176	      { return _Traits::max_size(_M_allocator) - _M_extra; }
   177	
   178	      template<typename _Alloc2>
   179		friend bool
   180		operator==(const debug_allocator& __lhs,
   181			   const debug_allocator<_Alloc2>& __rhs) _GLIBCXX_NOTHROW
   182		{ return __lhs._M_allocator == debug_allocator(__rhs)._M_allocator; }
   183	
   184	#if __cpp_impl_three_way_comparison < 201907L
   185	      template<typename _Alloc2>
   186		friend bool
   187		operator!=(const debug_allocator& __lhs,
   188			   const debug_allocator<_Alloc2>& __rhs) _GLIBCXX_NOTHROW
   189		{ return !(__lhs == __rhs); }
   190	#endif
   191	    };
   192	
   193	_GLIBCXX_END_NAMESPACE_VERSION
   194	} // namespace
   195	
   196	#endif