1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #ifndef _LIBCPP___ITERATOR_MOVE_SENTINEL_H
10 #define _LIBCPP___ITERATOR_MOVE_SENTINEL_H
11 
12 #include <__concepts/assignable.h>
13 #include <__concepts/convertible_to.h>
14 #include <__concepts/semiregular.h>
15 #include <__config>
16 #include <__utility/move.h>
17 
18 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
19 #  pragma GCC system_header
20 #endif
21 
22 _LIBCPP_BEGIN_NAMESPACE_STD
23 
24 #if _LIBCPP_STD_VER > 17
25 
26 template <semiregular _Sent>
27 class _LIBCPP_TEMPLATE_VIS move_sentinel
28 {
29 public:
30   _LIBCPP_HIDE_FROM_ABI
31   move_sentinel() = default;
32 
33   _LIBCPP_HIDE_FROM_ABI constexpr
34   explicit move_sentinel(_Sent __s) : __last_(std::move(__s)) {}
35 
36   template <class _S2>
37     requires convertible_to<const _S2&, _Sent>
38   _LIBCPP_HIDE_FROM_ABI constexpr
39   move_sentinel(const move_sentinel<_S2>& __s) : __last_(__s.base()) {}
40 
41   template <class _S2>
42     requires assignable_from<_Sent&, const _S2&>
43   _LIBCPP_HIDE_FROM_ABI constexpr
44   move_sentinel& operator=(const move_sentinel<_S2>& __s)
45     { __last_ = __s.base(); return *this; }
46 
47   constexpr _Sent base() const { return __last_; }
48 
49 private:
50     _Sent __last_ = _Sent();
51 };
52 
53 #endif // _LIBCPP_STD_VER > 17
54 
55 _LIBCPP_END_NAMESPACE_STD
56 
57 #endif // _LIBCPP___ITERATOR_MOVE_SENTINEL_H
58