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 {
  32 public:
  33   _LIBCPP_HIDE_FROM_ABI
  34   move_sentinel() = default;
  35
  36   _LIBCPP_HIDE_FROM_ABI constexpr
  37   explicit move_sentinel(_Sent __s) : __last_(std::move(__s)) {}
  38
  39   template <class _S2>
  40     requires convertible_to<const _S2&, _Sent>
  41   _LIBCPP_HIDE_FROM_ABI constexpr
  42   move_sentinel(const move_sentinel<_S2>& __s) : __last_(__s.base()) {}
  43
  44   template <class _S2>
  45     requires assignable_from<_Sent&, const _S2&>
  46   _LIBCPP_HIDE_FROM_ABI constexpr
  47   move_sentinel& operator=(const move_sentinel<_S2>& __s)
  48     { __last_ = __s.base(); return *this; }
  49
  50   _LIBCPP_HIDE_FROM_ABI constexpr _Sent base() const { return __last_; }
  51
  52 private:
  53     _Sent __last_ = _Sent();
  54 };
  55
  56 _LIBCPP_CTAD_SUPPORTED_FOR_TYPE(move_sentinel);
  57
  58 #endif // _LIBCPP_STD_VER >= 20
  59
  60 _LIBCPP_END_NAMESPACE_STD
  61
  62 _LIBCPP_POP_MACROS
  63
  64 #endif // _LIBCPP___ITERATOR_MOVE_SENTINEL_H