stl_uninitialized.h

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// Raw memory manipulators -*- C++ -*-

// Copyright (C) 2001-2018 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
// <http://www.gnu.org/licenses/>.

/*
 *
 * Copyright (c) 1994
 * Hewlett-Packard Company
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Hewlett-Packard Company makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 *
 *
 * Copyright (c) 1996,1997
 * Silicon Graphics Computer Systems, Inc.
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Silicon Graphics makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 */

/** @file bits/stl_uninitialized.h
 *  This is an internal header file, included by other library headers.
 *  Do not attempt to use it directly. @headername{memory}
 */

#ifndef _STL_UNINITIALIZED_H
#define _STL_UNINITIALIZED_H 1

#if __cplusplus > 201402L
#include <utility>
#endif

#if __cplusplus >= 201103L
#include <type_traits>
#endif

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

  template<bool _TrivialValueTypes>
    struct __uninitialized_copy
    {
      template<typename _InputIterator, typename _ForwardIterator>
        static _ForwardIterator
        __uninit_copy(_InputIterator __first, _InputIterator __last,
                      _ForwardIterator __result)
        {
          _ForwardIterator __cur = __result;
          __try
            {
              for (; __first != __last; ++__first, (void)++__cur)
                std::_Construct(std::__addressof(*__cur), *__first);
              return __cur;
            }
          __catch(...)
            {
              std::_Destroy(__result, __cur);
              __throw_exception_again;
            }
        }
    };

  template<>
    struct __uninitialized_copy<true>
    {
      template<typename _InputIterator, typename _ForwardIterator>
        static _ForwardIterator
        __uninit_copy(_InputIterator __first, _InputIterator __last,
                      _ForwardIterator __result)
        { return std::copy(__first, __last, __result); }
    };

  /**
   *  @brief Copies the range [first,last) into result.
   *  @param  __first  An input iterator.
   *  @param  __last   An input iterator.
   *  @param  __result An output iterator.
   *  @return   __result + (__first - __last)
   *
   *  Like copy(), but does not require an initialized output range.
  */
  template<typename _InputIterator, typename _ForwardIterator>
    inline _ForwardIterator
    uninitialized_copy(_InputIterator __first, _InputIterator __last,
                       _ForwardIterator __result)
    {
      typedef typename iterator_traits<_InputIterator>::value_type
        _ValueType1;
      typedef typename iterator_traits<_ForwardIterator>::value_type
        _ValueType2;
#if __cplusplus < 201103L
      const bool __assignable = true;
#else
      // trivial types can have deleted assignment
      typedef typename iterator_traits<_InputIterator>::reference _RefType1;
      typedef typename iterator_traits<_ForwardIterator>::reference _RefType2;
      const bool __assignable = is_assignable<_RefType2, _RefType1>::value;
#endif

      return std::__uninitialized_copy<__is_trivial(_ValueType1)
                                       && __is_trivial(_ValueType2)
                                       && __assignable>::
        __uninit_copy(__first, __last, __result);
    }


  template<bool _TrivialValueType>
    struct __uninitialized_fill
    {
      template<typename _ForwardIterator, typename _Tp>
        static void
        __uninit_fill(_ForwardIterator __first, _ForwardIterator __last,
                      const _Tp& __x)
        {
          _ForwardIterator __cur = __first;
          __try
            {
              for (; __cur != __last; ++__cur)
                std::_Construct(std::__addressof(*__cur), __x);
            }
          __catch(...)
            {
              std::_Destroy(__first, __cur);
              __throw_exception_again;
            }
        }
    };

  template<>
    struct __uninitialized_fill<true>
    {
      template<typename _ForwardIterator, typename _Tp>
        static void
        __uninit_fill(_ForwardIterator __first, _ForwardIterator __last,
                      const _Tp& __x)
        { std::fill(__first, __last, __x); }
    };

  /**
   *  @brief Copies the value x into the range [first,last).
   *  @param  __first  An input iterator.
   *  @param  __last   An input iterator.
   *  @param  __x      The source value.
   *  @return   Nothing.
   *
   *  Like fill(), but does not require an initialized output range.
  */
  template<typename _ForwardIterator, typename _Tp>
    inline void
    uninitialized_fill(_ForwardIterator __first, _ForwardIterator __last,
                       const _Tp& __x)
    {
      typedef typename iterator_traits<_ForwardIterator>::value_type
        _ValueType;
#if __cplusplus < 201103L
      const bool __assignable = true;
#else
      // trivial types can have deleted assignment
      const bool __assignable = is_copy_assignable<_ValueType>::value;
#endif

      std::__uninitialized_fill<__is_trivial(_ValueType) && __assignable>::
        __uninit_fill(__first, __last, __x);
    }


  template<bool _TrivialValueType>
    struct __uninitialized_fill_n
    {
      template<typename _ForwardIterator, typename _Size, typename _Tp>
        static _ForwardIterator
        __uninit_fill_n(_ForwardIterator __first, _Size __n,
                        const _Tp& __x)
        {
          _ForwardIterator __cur = __first;
          __try
            {
              for (; __n > 0; --__n, (void) ++__cur)
                std::_Construct(std::__addressof(*__cur), __x);
              return __cur;
            }
          __catch(...)
            {
              std::_Destroy(__first, __cur);
              __throw_exception_again;
            }
        }
    };

  template<>
    struct __uninitialized_fill_n<true>
    {
      template<typename _ForwardIterator, typename _Size, typename _Tp>
        static _ForwardIterator
        __uninit_fill_n(_ForwardIterator __first, _Size __n,
                        const _Tp& __x)
        { return std::fill_n(__first, __n, __x); }
    };

   // _GLIBCXX_RESOLVE_LIB_DEFECTS
   // DR 1339. uninitialized_fill_n should return the end of its range
  /**
   *  @brief Copies the value x into the range [first,first+n).
   *  @param  __first  An input iterator.
   *  @param  __n      The number of copies to make.
   *  @param  __x      The source value.
   *  @return   Nothing.
   *
   *  Like fill_n(), but does not require an initialized output range.
  */
  template<typename _ForwardIterator, typename _Size, typename _Tp>
    inline _ForwardIterator
    uninitialized_fill_n(_ForwardIterator __first, _Size __n, const _Tp& __x)
    {
      typedef typename iterator_traits<_ForwardIterator>::value_type
        _ValueType;
#if __cplusplus < 201103L
      const bool __assignable = true;
#else
      // trivial types can have deleted assignment
      const bool __assignable = is_copy_assignable<_ValueType>::value;
#endif
      return __uninitialized_fill_n<__is_trivial(_ValueType) && __assignable>::
        __uninit_fill_n(__first, __n, __x);
    }

  // Extensions: versions of uninitialized_copy, uninitialized_fill,
  //  and uninitialized_fill_n that take an allocator parameter.
  //  We dispatch back to the standard versions when we're given the
  //  default allocator.  For nondefault allocators we do not use 
  //  any of the POD optimizations.

  template<typename _InputIterator, typename _ForwardIterator,
           typename _Allocator>
    _ForwardIterator
    __uninitialized_copy_a(_InputIterator __first, _InputIterator __last,
                           _ForwardIterator __result, _Allocator& __alloc)
    {
      _ForwardIterator __cur = __result;
      __try
        {
          typedef __gnu_cxx::__alloc_traits<_Allocator> __traits;
          for (; __first != __last; ++__first, (void)++__cur)
            __traits::construct(__alloc, std::__addressof(*__cur), *__first);
          return __cur;
        }
      __catch(...)
        {
          std::_Destroy(__result, __cur, __alloc);
          __throw_exception_again;
        }
    }

  template<typename _InputIterator, typename _ForwardIterator, typename _Tp>
    inline _ForwardIterator
    __uninitialized_copy_a(_InputIterator __first, _InputIterator __last,
                           _ForwardIterator __result, allocator<_Tp>&)
    { return std::uninitialized_copy(__first, __last, __result); }

  template<typename _InputIterator, typename _ForwardIterator,
           typename _Allocator>
    inline _ForwardIterator
    __uninitialized_move_a(_InputIterator __first, _InputIterator __last,
                           _ForwardIterator __result, _Allocator& __alloc)
    {
      return std::__uninitialized_copy_a(_GLIBCXX_MAKE_MOVE_ITERATOR(__first),
                                         _GLIBCXX_MAKE_MOVE_ITERATOR(__last),
                                         __result, __alloc);
    }

  template<typename _InputIterator, typename _ForwardIterator,
           typename _Allocator>
    inline _ForwardIterator
    __uninitialized_move_if_noexcept_a(_InputIterator __first,
                                       _InputIterator __last,
                                       _ForwardIterator __result,
                                       _Allocator& __alloc)
    {
      return std::__uninitialized_copy_a
        (_GLIBCXX_MAKE_MOVE_IF_NOEXCEPT_ITERATOR(__first),
         _GLIBCXX_MAKE_MOVE_IF_NOEXCEPT_ITERATOR(__last), __result, __alloc);
    }

  template<typename _ForwardIterator, typename _Tp, typename _Allocator>
    void
    __uninitialized_fill_a(_ForwardIterator __first, _ForwardIterator __last,
                           const _Tp& __x, _Allocator& __alloc)
    {
      _ForwardIterator __cur = __first;
      __try
        {
          typedef __gnu_cxx::__alloc_traits<_Allocator> __traits;
          for (; __cur != __last; ++__cur)
            __traits::construct(__alloc, std::__addressof(*__cur), __x);
        }
      __catch(...)
        {
          std::_Destroy(__first, __cur, __alloc);
          __throw_exception_again;
        }
    }

  template<typename _ForwardIterator, typename _Tp, typename _Tp2>
    inline void
    __uninitialized_fill_a(_ForwardIterator __first, _ForwardIterator __last,
                           const _Tp& __x, allocator<_Tp2>&)
    { std::uninitialized_fill(__first, __last, __x); }

  template<typename _ForwardIterator, typename _Size, typename _Tp,
           typename _Allocator>
    _ForwardIterator
    __uninitialized_fill_n_a(_ForwardIterator __first, _Size __n, 
                             const _Tp& __x, _Allocator& __alloc)
    {
      _ForwardIterator __cur = __first;
      __try
        {
          typedef __gnu_cxx::__alloc_traits<_Allocator> __traits;
          for (; __n > 0; --__n, (void) ++__cur)
            __traits::construct(__alloc, std::__addressof(*__cur), __x);
          return __cur;
        }
      __catch(...)
        {
          std::_Destroy(__first, __cur, __alloc);
          __throw_exception_again;
        }
    }

  template<typename _ForwardIterator, typename _Size, typename _Tp,
           typename _Tp2>
    inline _ForwardIterator
    __uninitialized_fill_n_a(_ForwardIterator __first, _Size __n, 
                             const _Tp& __x, allocator<_Tp2>&)
    { return std::uninitialized_fill_n(__first, __n, __x); }


  // Extensions: __uninitialized_copy_move, __uninitialized_move_copy,
  // __uninitialized_fill_move, __uninitialized_move_fill.
  // All of these algorithms take a user-supplied allocator, which is used
  // for construction and destruction.

  // __uninitialized_copy_move
  // Copies [first1, last1) into [result, result + (last1 - first1)), and
  //  move [first2, last2) into
  //  [result, result + (last1 - first1) + (last2 - first2)).
  template<typename _InputIterator1, typename _InputIterator2,
           typename _ForwardIterator, typename _Allocator>
    inline _ForwardIterator
    __uninitialized_copy_move(_InputIterator1 __first1,
                              _InputIterator1 __last1,
                              _InputIterator2 __first2,
                              _InputIterator2 __last2,
                              _ForwardIterator __result,
                              _Allocator& __alloc)
    {
      _ForwardIterator __mid = std::__uninitialized_copy_a(__first1, __last1,
                                                           __result,
                                                           __alloc);
      __try
        {
          return std::__uninitialized_move_a(__first2, __last2, __mid, __alloc);
        }
      __catch(...)
        {
          std::_Destroy(__result, __mid, __alloc);
          __throw_exception_again;
        }
    }

  // __uninitialized_move_copy
  // Moves [first1, last1) into [result, result + (last1 - first1)), and
  //  copies [first2, last2) into
  //  [result, result + (last1 - first1) + (last2 - first2)).
  template<typename _InputIterator1, typename _InputIterator2,
           typename _ForwardIterator, typename _Allocator>
    inline _ForwardIterator
    __uninitialized_move_copy(_InputIterator1 __first1,
                              _InputIterator1 __last1,
                              _InputIterator2 __first2,
                              _InputIterator2 __last2,
                              _ForwardIterator __result,
                              _Allocator& __alloc)
    {
      _ForwardIterator __mid = std::__uninitialized_move_a(__first1, __last1,
                                                           __result,
                                                           __alloc);
      __try
        {
          return std::__uninitialized_copy_a(__first2, __last2, __mid, __alloc);
        }
      __catch(...)
        {
          std::_Destroy(__result, __mid, __alloc);
          __throw_exception_again;
        }
    }
  
  // __uninitialized_fill_move
  // Fills [result, mid) with x, and moves [first, last) into
  //  [mid, mid + (last - first)).
  template<typename _ForwardIterator, typename _Tp, typename _InputIterator,
           typename _Allocator>
    inline _ForwardIterator
    __uninitialized_fill_move(_ForwardIterator __result, _ForwardIterator __mid,
                              const _Tp& __x, _InputIterator __first,
                              _InputIterator __last, _Allocator& __alloc)
    {
      std::__uninitialized_fill_a(__result, __mid, __x, __alloc);
      __try
        {
          return std::__uninitialized_move_a(__first, __last, __mid, __alloc);
        }
      __catch(...)
        {
          std::_Destroy(__result, __mid, __alloc);
          __throw_exception_again;
        }
    }

  // __uninitialized_move_fill
  // Moves [first1, last1) into [first2, first2 + (last1 - first1)), and
  //  fills [first2 + (last1 - first1), last2) with x.
  template<typename _InputIterator, typename _ForwardIterator, typename _Tp,
           typename _Allocator>
    inline void
    __uninitialized_move_fill(_InputIterator __first1, _InputIterator __last1,
                              _ForwardIterator __first2,
                              _ForwardIterator __last2, const _Tp& __x,
                              _Allocator& __alloc)
    {
      _ForwardIterator __mid2 = std::__uninitialized_move_a(__first1, __last1,
                                                            __first2,
                                                            __alloc);
      __try
        {
          std::__uninitialized_fill_a(__mid2, __last2, __x, __alloc);
        }
      __catch(...)
        {
          std::_Destroy(__first2, __mid2, __alloc);
          __throw_exception_again;
        }
    }

#if __cplusplus >= 201103L
  // Extensions: __uninitialized_default, __uninitialized_default_n,
  // __uninitialized_default_a, __uninitialized_default_n_a.

  template<bool _TrivialValueType>
    struct __uninitialized_default_1
    {
      template<typename _ForwardIterator>
        static void
        __uninit_default(_ForwardIterator __first, _ForwardIterator __last)
        {
          _ForwardIterator __cur = __first;
          __try
            {
              for (; __cur != __last; ++__cur)
                std::_Construct(std::__addressof(*__cur));
            }
          __catch(...)
            {
              std::_Destroy(__first, __cur);
              __throw_exception_again;
            }
        }
    };

  template<>
    struct __uninitialized_default_1<true>
    {
      template<typename _ForwardIterator>
        static void
        __uninit_default(_ForwardIterator __first, _ForwardIterator __last)
        {
          typedef typename iterator_traits<_ForwardIterator>::value_type
            _ValueType;

          std::fill(__first, __last, _ValueType());
        }
    };

  template<bool _TrivialValueType>
    struct __uninitialized_default_n_1
    {
      template<typename _ForwardIterator, typename _Size>
        static _ForwardIterator
        __uninit_default_n(_ForwardIterator __first, _Size __n)
        {
          _ForwardIterator __cur = __first;
          __try
            {
              for (; __n > 0; --__n, (void) ++__cur)
                std::_Construct(std::__addressof(*__cur));
              return __cur;
            }
          __catch(...)
            {
              std::_Destroy(__first, __cur);
              __throw_exception_again;
            }
        }
    };

  template<>
    struct __uninitialized_default_n_1<true>
    {
      template<typename _ForwardIterator, typename _Size>
        static _ForwardIterator
        __uninit_default_n(_ForwardIterator __first, _Size __n)
        {
          typedef typename iterator_traits<_ForwardIterator>::value_type
            _ValueType;

          return std::fill_n(__first, __n, _ValueType());
        }
    };

  // __uninitialized_default
  // Fills [first, last) with std::distance(first, last) default
  // constructed value_types(s).
  template<typename _ForwardIterator>
    inline void
    __uninitialized_default(_ForwardIterator __first,
                            _ForwardIterator __last)
    {
      typedef typename iterator_traits<_ForwardIterator>::value_type
        _ValueType;
      // trivial types can have deleted assignment
      const bool __assignable = is_copy_assignable<_ValueType>::value;

      std::__uninitialized_default_1<__is_trivial(_ValueType)
                                     && __assignable>::
        __uninit_default(__first, __last);
    }

  // __uninitialized_default_n
  // Fills [first, first + n) with n default constructed value_type(s).
  template<typename _ForwardIterator, typename _Size>
    inline _ForwardIterator
    __uninitialized_default_n(_ForwardIterator __first, _Size __n)
    {
      typedef typename iterator_traits<_ForwardIterator>::value_type
        _ValueType;
      // trivial types can have deleted assignment
      const bool __assignable = is_copy_assignable<_ValueType>::value;

      return __uninitialized_default_n_1<__is_trivial(_ValueType)
                                       && __assignable>::
        __uninit_default_n(__first, __n);
    }


  // __uninitialized_default_a
  // Fills [first, last) with std::distance(first, last) default
  // constructed value_types(s), constructed with the allocator alloc.
  template<typename _ForwardIterator, typename _Allocator>
    void
    __uninitialized_default_a(_ForwardIterator __first,
                              _ForwardIterator __last,
                              _Allocator& __alloc)
    {
      _ForwardIterator __cur = __first;
      __try
        {
          typedef __gnu_cxx::__alloc_traits<_Allocator> __traits;
          for (; __cur != __last; ++__cur)
            __traits::construct(__alloc, std::__addressof(*__cur));
        }
      __catch(...)
        {
          std::_Destroy(__first, __cur, __alloc);
          __throw_exception_again;
        }
    }

  template<typename _ForwardIterator, typename _Tp>
    inline void
    __uninitialized_default_a(_ForwardIterator __first,
                              _ForwardIterator __last,
                              allocator<_Tp>&)
    { std::__uninitialized_default(__first, __last); }


  // __uninitialized_default_n_a
  // Fills [first, first + n) with n default constructed value_types(s),
  // constructed with the allocator alloc.
  template<typename _ForwardIterator, typename _Size, typename _Allocator>
    _ForwardIterator
    __uninitialized_default_n_a(_ForwardIterator __first, _Size __n, 
                                _Allocator& __alloc)
    {
      _ForwardIterator __cur = __first;
      __try
        {
          typedef __gnu_cxx::__alloc_traits<_Allocator> __traits;
          for (; __n > 0; --__n, (void) ++__cur)
            __traits::construct(__alloc, std::__addressof(*__cur));
          return __cur;
        }
      __catch(...)
        {
          std::_Destroy(__first, __cur, __alloc);
          __throw_exception_again;
        }
    }

  template<typename _ForwardIterator, typename _Size, typename _Tp>
    inline _ForwardIterator
    __uninitialized_default_n_a(_ForwardIterator __first, _Size __n, 
                                allocator<_Tp>&)
    { return std::__uninitialized_default_n(__first, __n); }

  template<bool _TrivialValueType>
    struct __uninitialized_default_novalue_1
    {
      template<typename _ForwardIterator>
        static void
        __uninit_default_novalue(_ForwardIterator __first,
                                 _ForwardIterator __last)
        {
          _ForwardIterator __cur = __first;
          __try
            {
              for (; __cur != __last; ++__cur)
                std::_Construct_novalue(std::__addressof(*__cur));
            }
          __catch(...)
            {
              std::_Destroy(__first, __cur);
              __throw_exception_again;
            }
        }
    };

  template<>
    struct __uninitialized_default_novalue_1<true>
    {
      template<typename _ForwardIterator>
        static void
        __uninit_default_novalue(_ForwardIterator __first,
                                 _ForwardIterator __last)
        {
        }
    };

  template<bool _TrivialValueType>
    struct __uninitialized_default_novalue_n_1
    {
      template<typename _ForwardIterator, typename _Size>
        static _ForwardIterator
        __uninit_default_novalue_n(_ForwardIterator __first, _Size __n)
        {
          _ForwardIterator __cur = __first;
          __try
            {
              for (; __n > 0; --__n, (void) ++__cur)
                std::_Construct_novalue(std::__addressof(*__cur));
              return __cur;
            }
          __catch(...)
            {
              std::_Destroy(__first, __cur);
              __throw_exception_again;
            }
        }
    };

  template<>
    struct __uninitialized_default_novalue_n_1<true>
    {
      template<typename _ForwardIterator, typename _Size>
        static _ForwardIterator
        __uninit_default_novalue_n(_ForwardIterator __first, _Size __n)
        { return std::next(__first, __n); }
    };

  // __uninitialized_default_novalue
  // Fills [first, last) with std::distance(first, last) default-initialized
  // value_types(s).
  template<typename _ForwardIterator>
    inline void
    __uninitialized_default_novalue(_ForwardIterator __first,
                                    _ForwardIterator __last)
    {
      typedef typename iterator_traits<_ForwardIterator>::value_type
        _ValueType;

      std::__uninitialized_default_novalue_1<
        is_trivially_default_constructible<_ValueType>::value>::
        __uninit_default_novalue(__first, __last);
    }

  // __uninitialized_default_n
  // Fills [first, first + n) with n default-initialized value_type(s).
  template<typename _ForwardIterator, typename _Size>
    inline _ForwardIterator
    __uninitialized_default_novalue_n(_ForwardIterator __first, _Size __n)
    {
      typedef typename iterator_traits<_ForwardIterator>::value_type
        _ValueType;

      return __uninitialized_default_novalue_n_1<
        is_trivially_default_constructible<_ValueType>::value>::
        __uninit_default_novalue_n(__first, __n);
    }

  template<typename _InputIterator, typename _Size,
           typename _ForwardIterator>
    _ForwardIterator
    __uninitialized_copy_n(_InputIterator __first, _Size __n,
                           _ForwardIterator __result, input_iterator_tag)
    {
      _ForwardIterator __cur = __result;
      __try
        {
          for (; __n > 0; --__n, (void) ++__first, ++__cur)
            std::_Construct(std::__addressof(*__cur), *__first);
          return __cur;
        }
      __catch(...)
        {
          std::_Destroy(__result, __cur);
          __throw_exception_again;
        }
    }

  template<typename _RandomAccessIterator, typename _Size,
           typename _ForwardIterator>
    inline _ForwardIterator
    __uninitialized_copy_n(_RandomAccessIterator __first, _Size __n,
                           _ForwardIterator __result,
                           random_access_iterator_tag)
    { return std::uninitialized_copy(__first, __first + __n, __result); }

  template<typename _InputIterator, typename _Size,
           typename _ForwardIterator>
    pair<_InputIterator, _ForwardIterator>
    __uninitialized_copy_n_pair(_InputIterator __first, _Size __n,
                           _ForwardIterator __result, input_iterator_tag)
    {
      _ForwardIterator __cur = __result;
      __try
        {
          for (; __n > 0; --__n, (void) ++__first, ++__cur)
            std::_Construct(std::__addressof(*__cur), *__first);
          return {__first, __cur};
        }
      __catch(...)
        {
          std::_Destroy(__result, __cur);
          __throw_exception_again;
        }
    }

  template<typename _RandomAccessIterator, typename _Size,
           typename _ForwardIterator>
    inline pair<_RandomAccessIterator, _ForwardIterator>
    __uninitialized_copy_n_pair(_RandomAccessIterator __first, _Size __n,
                           _ForwardIterator __result,
                           random_access_iterator_tag)
    {
      auto __second_res = uninitialized_copy(__first, __first + __n, __result);
      auto __first_res = std::next(__first, __n);
      return {__first_res, __second_res};
    }

  /**
   *  @brief Copies the range [first,first+n) into result.
   *  @param  __first  An input iterator.
   *  @param  __n      The number of elements to copy.
   *  @param  __result An output iterator.
   *  @return  __result + __n
   *
   *  Like copy_n(), but does not require an initialized output range.
  */
  template<typename _InputIterator, typename _Size, typename _ForwardIterator>
    inline _ForwardIterator
    uninitialized_copy_n(_InputIterator __first, _Size __n,
                         _ForwardIterator __result)
    { return std::__uninitialized_copy_n(__first, __n, __result,
                                         std::__iterator_category(__first)); }

  template<typename _InputIterator, typename _Size, typename _ForwardIterator>
    inline pair<_InputIterator, _ForwardIterator>
    __uninitialized_copy_n_pair(_InputIterator __first, _Size __n,
                              _ForwardIterator __result)
    {
      return
        std::__uninitialized_copy_n_pair(__first, __n, __result,
                                         std::__iterator_category(__first));
    }

#endif

#if __cplusplus >= 201703L
# define __cpp_lib_raw_memory_algorithms 201606L

  template <typename _ForwardIterator>
    inline void
    uninitialized_default_construct(_ForwardIterator __first,
                                    _ForwardIterator __last)
    {
      __uninitialized_default_novalue(__first, __last);
    }

  template <typename _ForwardIterator, typename _Size>
    inline _ForwardIterator
    uninitialized_default_construct_n(_ForwardIterator __first, _Size __count)
    {
      return __uninitialized_default_novalue_n(__first, __count);
    }

  template <typename _ForwardIterator>
    inline void
    uninitialized_value_construct(_ForwardIterator __first,
                                  _ForwardIterator __last)
    {
      return __uninitialized_default(__first, __last);
    }

  template <typename _ForwardIterator, typename _Size>
    inline _ForwardIterator
    uninitialized_value_construct_n(_ForwardIterator __first, _Size __count)
    {
      return __uninitialized_default_n(__first, __count);
    }

  template <typename _InputIterator, typename _ForwardIterator>
    inline _ForwardIterator
    uninitialized_move(_InputIterator __first, _InputIterator __last,
                       _ForwardIterator __result)
    {
      return std::uninitialized_copy
        (_GLIBCXX_MAKE_MOVE_ITERATOR(__first),
         _GLIBCXX_MAKE_MOVE_ITERATOR(__last), __result);
    }

  template <typename _InputIterator, typename _Size, typename _ForwardIterator>
    inline pair<_InputIterator, _ForwardIterator>
    uninitialized_move_n(_InputIterator __first, _Size __count,
                         _ForwardIterator __result)
    {
      auto __res = std::__uninitialized_copy_n_pair
        (_GLIBCXX_MAKE_MOVE_ITERATOR(__first),
         __count, __result);
      return {__res.first.base(), __res.second};
    }
#endif // C++17

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace

#endif /* _STL_UNINITIALIZED_H */