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// Pointer Traits -*- C++ -*-

// Copyright (C) 2011-2012 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

// <http://www.gnu.org/licenses/>.

/** @file bits/ptr_traits.h

 *  This is an internal header file, included by other library headers.

 *  Do not attempt to use it directly. @headername{memory}

 */

#ifndef _PTR_TRAITS_H

#define _PTR_TRAITS_H 1

#if __cplusplus >= 201103L

#include <type_traits> // For _GLIBCXX_HAS_NESTED_TYPE

namespace std _GLIBCXX_VISIBILITY(default)

{

_GLIBCXX_BEGIN_NAMESPACE_VERSION

_GLIBCXX_HAS_NESTED_TYPE(element_type)

_GLIBCXX_HAS_NESTED_TYPE(difference_type)

  template<typename _Tp, bool = __has_element_type<_Tp>::value>

    struct __ptrtr_elt_type;

  template<typename _Tp>

    struct __ptrtr_elt_type<_Tp, true>

    {

      typedef typename _Tp::element_type __type;

    };

  template<template<typename, typename...> class _SomePtr, typename _Tp,

            typename... _Args>

    struct __ptrtr_elt_type<_SomePtr<_Tp, _Args...>, false>

    {

      typedef _Tp __type;

    };

  template<typename _Tp, bool = __has_difference_type<_Tp>::value>

    struct __ptrtr_diff_type

    {

      typedef typename _Tp::difference_type __type;

    };

  template<typename _Tp>

    struct __ptrtr_diff_type<_Tp, false>

    {

      typedef ptrdiff_t __type;

    };

  template<typename _Ptr, typename _Up>

    class __ptrtr_rebind_helper

    {

      template<typename _Ptr2, typename _Up2>

        static constexpr bool

        _S_chk(typename _Ptr2::template rebind<_Up2>*)

        { return true; }

      template<typename, typename>

        static constexpr bool

        _S_chk(...)

        { return false; }

    public:

      static const bool __value = _S_chk<_Ptr, _Up>(nullptr);

    };

  template<typename _Ptr, typename _Up>

    const bool __ptrtr_rebind_helper<_Ptr, _Up>::__value;

  template<typename _Tp, typename _Up,

           bool = __ptrtr_rebind_helper<_Tp, _Up>::__value>

    struct __ptrtr_rebind;

  template<typename _Tp, typename _Up>

    struct __ptrtr_rebind<_Tp, _Up, true>

    {

      typedef typename _Tp::template rebind<_Up> __type;

    };

  template<template<typename, typename...> class _SomePtr, typename _Up,

            typename _Tp, typename... _Args>

    struct __ptrtr_rebind<_SomePtr<_Tp, _Args...>, _Up, false>

    {

      typedef _SomePtr<_Up, _Args...> __type;

    };

  template<typename _Tp, typename = typename remove_cv<_Tp>::type>

    struct __ptrtr_not_void

    {

      typedef _Tp __type;

    };

  template<typename _Tp>

    struct __ptrtr_not_void<_Tp, void>

    {

      struct __type { };

    };

  template<typename _Ptr>

    class __ptrtr_pointer_to

    {

      typedef typename __ptrtr_elt_type<_Ptr>::__type   __orig_type;

      typedef typename __ptrtr_not_void<__orig_type>::__type __element_type;

    public:

      static _Ptr pointer_to(__element_type& __e)

      { return _Ptr::pointer_to(__e); }

    };

  /**

   * @brief  Uniform interface to all pointer-like types

   * @ingroup pointer_abstractions

  */

  template<typename _Ptr>

    struct pointer_traits : __ptrtr_pointer_to<_Ptr>

    {

      /// The pointer type

      typedef _Ptr                                      pointer;

      /// The type pointed to

      typedef typename __ptrtr_elt_type<_Ptr>::__type   element_type;

      /// Type used to represent the difference between two pointers

      typedef typename __ptrtr_diff_type<_Ptr>::__type  difference_type;

      template<typename _Up>

        using rebind = typename __ptrtr_rebind<_Ptr, _Up>::__type;

    };

  /**

   * @brief  Partial specialization for built-in pointers.

   * @ingroup pointer_abstractions

  */

  template<typename _Tp>

    struct pointer_traits<_Tp*>

    {

      /// The pointer type

      typedef _Tp* pointer;

      /// The type pointed to

      typedef _Tp  element_type;

      /// Type used to represent the difference between two pointers

      typedef ptrdiff_t difference_type;

      template<typename _Up>

        using rebind = _Up*;

      /**

       *  @brief  Obtain a pointer to an object

       *  @param  __r  A reference to an object of type @c element_type

       *  @return @c addressof(__r)

      */

      static pointer

      pointer_to(typename __ptrtr_not_void<element_type>::__type& __r) noexcept

      { return std::addressof(__r); }

    };

_GLIBCXX_END_NAMESPACE_VERSION

} // namespace std

#endif

#endif