libcxx/include/__iterator/move_sentinel.h

   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_PUSH_MACROS
  23 #include <__undef_macros>
  24
  25 _LIBCPP_BEGIN_NAMESPACE_STD
  26
  27 #if _LIBCPP_STD_VER >= 20
  28
  29 template <semiregular _Sent>
  30 class _LIBCPP_TEMPLATE_VIS move_sentinel {
  31 public:
  32   _LIBCPP_HIDE_FROM_ABI move_sentinel() = default;
  33
  34   _LIBCPP_HIDE_FROM_ABI constexpr 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 move_sentinel(const move_sentinel<_S2>& __s) : __last_(__s.base()) {}
  39
  40   template <class _S2>
  41     requires assignable_from<_Sent&, const _S2&>
  42   _LIBCPP_HIDE_FROM_ABI constexpr move_sentinel& operator=(const move_sentinel<_S2>& __s) {
  43     __last_ = __s.base();
  44     return *this;
  45   }
  46
  47   _LIBCPP_HIDE_FROM_ABI constexpr _Sent base() const { return __last_; }
  48
  49 private:
  50   _Sent __last_ = _Sent();
  51 };
  52
  53 _LIBCPP_CTAD_SUPPORTED_FOR_TYPE(move_sentinel);
  54
  55 #endif // _LIBCPP_STD_VER >= 20
  56
  57 _LIBCPP_END_NAMESPACE_STD
  58
  59 _LIBCPP_POP_MACROS
  60
  61 #endif // _LIBCPP___ITERATOR_MOVE_SENTINEL_H