//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP___ITERATOR_MOVE_SENTINEL_H
#define _LIBCPP___ITERATOR_MOVE_SENTINEL_H

#include <__concepts/assignable.h>
#include <__concepts/convertible_to.h>
#include <__concepts/semiregular.h>
#include <__config>
#include <__utility/move.h>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#  pragma GCC system_header
#endif

_LIBCPP_BEGIN_NAMESPACE_STD

#if _LIBCPP_STD_VER > 17

template <semiregular _Sent>
class _LIBCPP_TEMPLATE_VIS move_sentinel
{
public:
  _LIBCPP_HIDE_FROM_ABI
  move_sentinel() = default;

  _LIBCPP_HIDE_FROM_ABI constexpr
  explicit move_sentinel(_Sent __s) : __last_(std::move(__s)) {}

  template <class _S2>
    requires convertible_to<const _S2&, _Sent>
  _LIBCPP_HIDE_FROM_ABI constexpr
  move_sentinel(const move_sentinel<_S2>& __s) : __last_(__s.base()) {}

  template <class _S2>
    requires assignable_from<_Sent&, const _S2&>
  _LIBCPP_HIDE_FROM_ABI constexpr
  move_sentinel& operator=(const move_sentinel<_S2>& __s)
    { __last_ = __s.base(); return *this; }

  constexpr _Sent base() const { return __last_; }

private:
    _Sent __last_ = _Sent();
};

#endif // _LIBCPP_STD_VER > 17

_LIBCPP_END_NAMESPACE_STD

#endif // _LIBCPP___ITERATOR_MOVE_SENTINEL_H