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       1             : // Allocator traits -*- C++ -*-
       2             : 
       3             : // Copyright (C) 2011-2022 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             : /** @file ext/alloc_traits.h
      26             :  *  This file is a GNU extension to the Standard C++ Library.
      27             :  */
      28             : 
      29             : #ifndef _EXT_ALLOC_TRAITS_H
      30             : #define _EXT_ALLOC_TRAITS_H 1
      31             : 
      32             : #pragma GCC system_header
      33             : 
      34             : # include <bits/alloc_traits.h>
      35             : #if __cplusplus < 201103L
      36             : # include <bits/allocator.h>  // for __alloc_swap
      37             : #endif
      38             : 
      39             : namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
      40             : {
      41             : _GLIBCXX_BEGIN_NAMESPACE_VERSION
      42             : 
      43             : /**
      44             :  * @brief  Uniform interface to C++98 and C++11 allocators.
      45             :  * @ingroup allocators
      46             : */
      47             : template<typename _Alloc, typename = typename _Alloc::value_type>
      48             :   struct __alloc_traits
      49             : #if __cplusplus >= 201103L
      50             :   : std::allocator_traits<_Alloc>
      51             : #endif
      52             :   {
      53             :     typedef _Alloc allocator_type;
      54             : #if __cplusplus >= 201103L
      55             :     typedef std::allocator_traits<_Alloc>           _Base_type;
      56             :     typedef typename _Base_type::value_type         value_type;
      57             :     typedef typename _Base_type::pointer            pointer;
      58             :     typedef typename _Base_type::const_pointer      const_pointer;
      59             :     typedef typename _Base_type::size_type          size_type;
      60             :     typedef typename _Base_type::difference_type    difference_type;
      61             :     // C++11 allocators do not define reference or const_reference
      62             :     typedef value_type&                             reference;
      63             :     typedef const value_type&                       const_reference;
      64             :     using _Base_type::allocate;
      65             :     using _Base_type::deallocate;
      66             :     using _Base_type::construct;
      67             :     using _Base_type::destroy;
      68             :     using _Base_type::max_size;
      69             : 
      70             :   private:
      71             :     template<typename _Ptr>
      72             :       using __is_custom_pointer
      73             :         = std::__and_<std::is_same<pointer, _Ptr>,
      74             :                       std::__not_<std::is_pointer<_Ptr>>>;
      75             : 
      76             :   public:
      77             :     // overload construct for non-standard pointer types
      78             :     template<typename _Ptr, typename... _Args>
      79             :       static _GLIBCXX14_CONSTEXPR
      80             :       std::__enable_if_t<__is_custom_pointer<_Ptr>::value>
      81             :       construct(_Alloc& __a, _Ptr __p, _Args&&... __args)
      82             :       noexcept(noexcept(_Base_type::construct(__a, std::__to_address(__p),
      83             :                                               std::forward<_Args>(__args)...)))
      84             :       {
      85             :         _Base_type::construct(__a, std::__to_address(__p),
      86             :                               std::forward<_Args>(__args)...);
      87             :       }
      88             : 
      89             :     // overload destroy for non-standard pointer types
      90             :     template<typename _Ptr>
      91             :       static _GLIBCXX14_CONSTEXPR
      92             :       std::__enable_if_t<__is_custom_pointer<_Ptr>::value>
      93             :       destroy(_Alloc& __a, _Ptr __p)
      94             :       noexcept(noexcept(_Base_type::destroy(__a, std::__to_address(__p))))
      95             :       { _Base_type::destroy(__a, std::__to_address(__p)); }
      96             : 
      97         116 :     static constexpr _Alloc _S_select_on_copy(const _Alloc& __a)
      98         116 :     { return _Base_type::select_on_container_copy_construction(__a); }
      99             : 
     100             :     static _GLIBCXX14_CONSTEXPR void _S_on_swap(_Alloc& __a, _Alloc& __b)
     101             :     { std::__alloc_on_swap(__a, __b); }
     102             : 
     103             :     static constexpr bool _S_propagate_on_copy_assign()
     104             :     { return _Base_type::propagate_on_container_copy_assignment::value; }
     105             : 
     106             :     static constexpr bool _S_propagate_on_move_assign()
     107             :     { return _Base_type::propagate_on_container_move_assignment::value; }
     108             : 
     109             :     static constexpr bool _S_propagate_on_swap()
     110             :     { return _Base_type::propagate_on_container_swap::value; }
     111             : 
     112             :     static constexpr bool _S_always_equal()
     113             :     { return _Base_type::is_always_equal::value; }
     114             : 
     115             :     static constexpr bool _S_nothrow_move()
     116             :     { return _S_propagate_on_move_assign() || _S_always_equal(); }
     117             : 
     118             :     template<typename _Tp>
     119             :       struct rebind
     120             :       { typedef typename _Base_type::template rebind_alloc<_Tp> other; };
     121             : #else // ! C++11
     122             : 
     123             :     typedef typename _Alloc::pointer                pointer;
     124             :     typedef typename _Alloc::const_pointer          const_pointer;
     125             :     typedef typename _Alloc::value_type             value_type;
     126             :     typedef typename _Alloc::reference              reference;
     127             :     typedef typename _Alloc::const_reference        const_reference;
     128             :     typedef typename _Alloc::size_type              size_type;
     129             :     typedef typename _Alloc::difference_type        difference_type;
     130             : 
     131             :     _GLIBCXX_NODISCARD static pointer
     132             :     allocate(_Alloc& __a, size_type __n)
     133             :     { return __a.allocate(__n); }
     134             : 
     135             :     template<typename _Hint>
     136             :       _GLIBCXX_NODISCARD static pointer
     137             :       allocate(_Alloc& __a, size_type __n, _Hint __hint)
     138             :       { return __a.allocate(__n, __hint); }
     139             : 
     140             :     static void deallocate(_Alloc& __a, pointer __p, size_type __n)
     141             :     { __a.deallocate(__p, __n); }
     142             : 
     143             :     template<typename _Tp>
     144             :       static void construct(_Alloc& __a, pointer __p, const _Tp& __arg)
     145             :       { __a.construct(__p, __arg); }
     146             : 
     147             :     static void destroy(_Alloc& __a, pointer __p)
     148             :     { __a.destroy(__p); }
     149             : 
     150             :     static size_type max_size(const _Alloc& __a)
     151             :     { return __a.max_size(); }
     152             : 
     153             :     static const _Alloc& _S_select_on_copy(const _Alloc& __a) { return __a; }
     154             : 
     155             :     static void _S_on_swap(_Alloc& __a, _Alloc& __b)
     156             :     {
     157             :       // _GLIBCXX_RESOLVE_LIB_DEFECTS
     158             :       // 431. Swapping containers with unequal allocators.
     159             :       std::__alloc_swap<_Alloc>::_S_do_it(__a, __b);
     160             :     }
     161             : 
     162             :     template<typename _Tp>
     163             :       struct rebind
     164             :       { typedef typename _Alloc::template rebind<_Tp>::other other; };
     165             : #endif // C++11
     166             :   };
     167             : 
     168             : _GLIBCXX_END_NAMESPACE_VERSION
     169             : } // namespace __gnu_cxx
     170             : 
     171             : #endif