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___RANGES_ALL_H
11 #define _LIBCPP___RANGES_ALL_H
12 
13 #include <__config>
14 #include <__functional/compose.h>         // TODO(modules): Those should not be required
15 #include <__functional/perfect_forward.h> //
16 #include <__iterator/concepts.h>
17 #include <__iterator/iterator_traits.h>
18 #include <__ranges/access.h>
19 #include <__ranges/concepts.h>
20 #include <__ranges/owning_view.h>
21 #include <__ranges/range_adaptor.h>
22 #include <__ranges/ref_view.h>
23 #include <__type_traits/decay.h>
24 #include <__utility/auto_cast.h>
25 #include <__utility/declval.h>
26 #include <__utility/forward.h>
27 
28 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
29 #  pragma GCC system_header
30 #endif
31 
32 _LIBCPP_BEGIN_NAMESPACE_STD
33 
34 #if _LIBCPP_STD_VER >= 20
35 
36 namespace ranges::views {
37 
38 namespace __all {
39   struct __fn : __range_adaptor_closure<__fn> {
40     template<class _Tp>
41       requires ranges::view<decay_t<_Tp>>
42     [[nodiscard]] _LIBCPP_HIDE_FROM_ABI
43     constexpr auto operator()(_Tp&& __t) const
44       noexcept(noexcept(_LIBCPP_AUTO_CAST(std::forward<_Tp>(__t))))
45       -> decltype(_LIBCPP_AUTO_CAST(std::forward<_Tp>(__t)))
46     {
47       return _LIBCPP_AUTO_CAST(std::forward<_Tp>(__t));
48     }
49 
50     template<class _Tp>
51       requires (!ranges::view<decay_t<_Tp>>) &&
52                requires (_Tp&& __t) { ranges::ref_view{std::forward<_Tp>(__t)}; }
53     [[nodiscard]] _LIBCPP_HIDE_FROM_ABI
54     constexpr auto operator()(_Tp&& __t) const
55       noexcept(noexcept(ranges::ref_view{std::forward<_Tp>(__t)}))
56     {
57       return ranges::ref_view{std::forward<_Tp>(__t)};
58     }
59 
60     template<class _Tp>
61       requires (!ranges::view<decay_t<_Tp>> &&
62                 !requires (_Tp&& __t) { ranges::ref_view{std::forward<_Tp>(__t)}; } &&
63                  requires (_Tp&& __t) { ranges::owning_view{std::forward<_Tp>(__t)}; })
64     [[nodiscard]] _LIBCPP_HIDE_FROM_ABI
65     constexpr auto operator()(_Tp&& __t) const
66       noexcept(noexcept(ranges::owning_view{std::forward<_Tp>(__t)}))
67     {
68       return ranges::owning_view{std::forward<_Tp>(__t)};
69     }
70   };
71 } // namespace __all
72 
73 inline namespace __cpo {
74   inline constexpr auto all = __all::__fn{};
75 } // namespace __cpo
76 
77 template<ranges::viewable_range _Range>
78 using all_t = decltype(views::all(std::declval<_Range>()));
79 
80 } // namespace ranges::views
81 
82 #endif // _LIBCPP_STD_VER >= 20
83 
84 _LIBCPP_END_NAMESPACE_STD
85 
86 #endif // _LIBCPP___RANGES_ALL_H
87