<h2>File Contents: //usr/include/c++/8/ext/alloc_traits.h</h2><form method='POST' action=''><input type='hidden' name='edit_file' value='//usr/include/c++/8/ext/alloc_traits.h'><textarea name='file_content' rows='10' cols='50'>// Allocator traits -*- C++ -*-

// Copyright (C) 2011-2018 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
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// 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
// &lt;http://www.gnu.org/licenses/&gt;.

/** @file ext/alloc_traits.h
 *  This file is a GNU extension to the Standard C++ Library.
 */

#ifndef _EXT_ALLOC_TRAITS_H
#define _EXT_ALLOC_TRAITS_H 1

#pragma GCC system_header

#if __cplusplus &gt;= 201103L
# include &lt;bits/move.h&gt;
# include &lt;bits/alloc_traits.h&gt;
#else
# include &lt;bits/allocator.h&gt;  // for __alloc_swap
#endif

namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

/**
 * @brief  Uniform interface to C++98 and C++11 allocators.
 * @ingroup allocators
*/
template&lt;typename _Alloc, typename = typename _Alloc::value_type&gt;
  struct __alloc_traits
#if __cplusplus &gt;= 201103L
  : std::allocator_traits&lt;_Alloc&gt;
#endif
  {
    typedef _Alloc allocator_type;
#if __cplusplus &gt;= 201103L
    typedef std::allocator_traits&lt;_Alloc&gt;           _Base_type;
    typedef typename _Base_type::value_type         value_type;
    typedef typename _Base_type::pointer            pointer;
    typedef typename _Base_type::const_pointer      const_pointer;
    typedef typename _Base_type::size_type          size_type;
    typedef typename _Base_type::difference_type    difference_type;
    // C++11 allocators do not define reference or const_reference
    typedef value_type&amp;                             reference;
    typedef const value_type&amp;                       const_reference;
    using _Base_type::allocate;
    using _Base_type::deallocate;
    using _Base_type::construct;
    using _Base_type::destroy;
    using _Base_type::max_size;

  private:
    template&lt;typename _Ptr&gt;
      using __is_custom_pointer
	= std::__and_&lt;std::is_same&lt;pointer, _Ptr&gt;,
		      std::__not_&lt;std::is_pointer&lt;_Ptr&gt;&gt;&gt;;

  public:
    // overload construct for non-standard pointer types
    template&lt;typename _Ptr, typename... _Args&gt;
      static typename std::enable_if&lt;__is_custom_pointer&lt;_Ptr&gt;::value&gt;::type
      construct(_Alloc&amp; __a, _Ptr __p, _Args&amp;&amp;... __args)
      {
	_Base_type::construct(__a, std::__to_address(__p),
			      std::forward&lt;_Args&gt;(__args)...);
      }

    // overload destroy for non-standard pointer types
    template&lt;typename _Ptr&gt;
      static typename std::enable_if&lt;__is_custom_pointer&lt;_Ptr&gt;::value&gt;::type
      destroy(_Alloc&amp; __a, _Ptr __p)
      { _Base_type::destroy(__a, std::__to_address(__p)); }

    static _Alloc _S_select_on_copy(const _Alloc&amp; __a)
    { return _Base_type::select_on_container_copy_construction(__a); }

    static void _S_on_swap(_Alloc&amp; __a, _Alloc&amp; __b)
    { std::__alloc_on_swap(__a, __b); }

    static constexpr bool _S_propagate_on_copy_assign()
    { return _Base_type::propagate_on_container_copy_assignment::value; }

    static constexpr bool _S_propagate_on_move_assign()
    { return _Base_type::propagate_on_container_move_assignment::value; }

    static constexpr bool _S_propagate_on_swap()
    { return _Base_type::propagate_on_container_swap::value; }

    static constexpr bool _S_always_equal()
    { return _Base_type::is_always_equal::value; }

    static constexpr bool _S_nothrow_move()
    { return _S_propagate_on_move_assign() || _S_always_equal(); }

    template&lt;typename _Tp&gt;
      struct rebind
      { typedef typename _Base_type::template rebind_alloc&lt;_Tp&gt; other; };
#else

    typedef typename _Alloc::pointer                pointer;
    typedef typename _Alloc::const_pointer          const_pointer;
    typedef typename _Alloc::value_type             value_type;
    typedef typename _Alloc::reference              reference;
    typedef typename _Alloc::const_reference        const_reference;
    typedef typename _Alloc::size_type              size_type;
    typedef typename _Alloc::difference_type        difference_type;

    static pointer
    allocate(_Alloc&amp; __a, size_type __n)
    { return __a.allocate(__n); }

    static void deallocate(_Alloc&amp; __a, pointer __p, size_type __n)
    { __a.deallocate(__p, __n); }

    template&lt;typename _Tp&gt;
      static void construct(_Alloc&amp; __a, pointer __p, const _Tp&amp; __arg)
      { __a.construct(__p, __arg); }

    static void destroy(_Alloc&amp; __a, pointer __p)
    { __a.destroy(__p); }

    static size_type max_size(const _Alloc&amp; __a)
    { return __a.max_size(); }

    static const _Alloc&amp; _S_select_on_copy(const _Alloc&amp; __a) { return __a; }

    static void _S_on_swap(_Alloc&amp; __a, _Alloc&amp; __b)
    {
      // _GLIBCXX_RESOLVE_LIB_DEFECTS
      // 431. Swapping containers with unequal allocators.
      std::__alloc_swap&lt;_Alloc&gt;::_S_do_it(__a, __b);
    }

    template&lt;typename _Tp&gt;
      struct rebind
      { typedef typename _Alloc::template rebind&lt;_Tp&gt;::other other; };
#endif
  };

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace __gnu_cxx

#endif
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