1 // -*- C++ -*-
2 //===----------------------------------------------------------------------===//
3 //
4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5 // See https://llvm.org/LICENSE.txt for license information.
6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #ifndef _LIBCPP___ITERATOR_CONCEPTS_H
11 #define _LIBCPP___ITERATOR_CONCEPTS_H
12 
13 #include <__config>
14 #include <concepts>
15 #include <__iterator/iter_move.h>
16 #include <__iterator/incrementable_traits.h>
17 #include <__iterator/iterator_traits.h>
18 #include <__iterator/readable_traits.h>
19 
20 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
21 #pragma GCC system_header
22 #endif
23 
24 _LIBCPP_PUSH_MACROS
25 #include <__undef_macros>
26 
27 _LIBCPP_BEGIN_NAMESPACE_STD
28 
29 #if !defined(_LIBCPP_HAS_NO_RANGES)
30 
31 // clang-format off
32 
33 // [iterator.concept.readable]
34 template<class _In>
35 concept __indirectly_readable_impl =
36   requires(const _In __in) {
37     typename iter_value_t<_In>;
38     typename iter_reference_t<_In>;
39     typename iter_rvalue_reference_t<_In>;
40     { *__in } -> same_as<iter_reference_t<_In> >;
41     { ranges::iter_move(__in) } -> same_as<iter_rvalue_reference_t<_In> >;
42   } &&
43   common_reference_with<iter_reference_t<_In>&&, iter_value_t<_In>&> &&
44   common_reference_with<iter_reference_t<_In>&&, iter_rvalue_reference_t<_In>&&> &&
45   common_reference_with<iter_rvalue_reference_t<_In>&&, const iter_value_t<_In>&>;
46 
47 template<class _In>
48 concept indirectly_readable = __indirectly_readable_impl<remove_cvref_t<_In> >;
49 
50 // [iterator.concept.writable]
51 template<class _Out, class _Tp>
52 concept indirectly_writable =
53   requires(_Out&& __o, _Tp&& __t) {
54     *__o = _VSTD::forward<_Tp>(__t);                        // not required to be equality-preserving
55     *_VSTD::forward<_Out>(__o) = _VSTD::forward<_Tp>(__t);  // not required to be equality-preserving
56     const_cast<const iter_reference_t<_Out>&&>(*__o) = _VSTD::forward<_Tp>(__t);                       // not required to be equality-preserving
57     const_cast<const iter_reference_t<_Out>&&>(*_VSTD::forward<_Out>(__o)) = _VSTD::forward<_Tp>(__t); // not required to be equality-preserving
58   };
59 
60 // clang-format on
61 
62 #endif // !defined(_LIBCPP_HAS_NO_RANGES)
63 
64 _LIBCPP_END_NAMESPACE_STD
65 
66 _LIBCPP_POP_MACROS
67 
68 #endif // _LIBCPP___ITERATOR_CONCEPTS_H
69