v1/__iterator/move_sentinel.h

0001 //===----------------------------------------------------------------------===//
0002 //
0003 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0004 // See https://llvm.org/LICENSE.txt for license information.
0005 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0006 //
0007 //===----------------------------------------------------------------------===//
0008
0009 #ifndef _LIBCPP___ITERATOR_MOVE_SENTINEL_H
0010 #define _LIBCPP___ITERATOR_MOVE_SENTINEL_H
0011
0012 #include <__concepts/assignable.h>
0013 #include <__concepts/convertible_to.h>
0014 #include <__concepts/semiregular.h>
0015 #include <__config>
0016 #include <__utility/move.h>
0017
0018 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
0019 #  pragma GCC system_header
0020 #endif
0021
0022 _LIBCPP_PUSH_MACROS
0023 #include <__undef_macros>
0024
0025 _LIBCPP_BEGIN_NAMESPACE_STD
0026
0027 #if _LIBCPP_STD_VER >= 20
0028
0029 template <semiregular _Sent>
0030 class _LIBCPP_TEMPLATE_VIS move_sentinel {
0031 public:
0032   _LIBCPP_HIDE_FROM_ABI move_sentinel() = default;
0033
0034   _LIBCPP_HIDE_FROM_ABI constexpr explicit move_sentinel(_Sent __s) : __last_(std::move(__s)) {}
0035
0036   template <class _S2>
0037     requires convertible_to<const _S2&, _Sent>
0038   _LIBCPP_HIDE_FROM_ABI constexpr move_sentinel(const move_sentinel<_S2>& __s) : __last_(__s.base()) {}
0039
0040   template <class _S2>
0041     requires assignable_from<_Sent&, const _S2&>
0042   _LIBCPP_HIDE_FROM_ABI constexpr move_sentinel& operator=(const move_sentinel<_S2>& __s) {
0043     __last_ = __s.base();
0044     return *this;
0045   }
0046
0047   _LIBCPP_HIDE_FROM_ABI constexpr _Sent base() const { return __last_; }
0048
0049 private:
0050   _Sent __last_ = _Sent();
0051 };
0052
0053 _LIBCPP_CTAD_SUPPORTED_FOR_TYPE(move_sentinel);
0054
0055 #endif // _LIBCPP_STD_VER >= 20
0056
0057 _LIBCPP_END_NAMESPACE_STD
0058
0059 _LIBCPP_POP_MACROS
0060
0061 #endif // _LIBCPP___ITERATOR_MOVE_SENTINEL_H