xref: /freebsd-src/contrib/llvm-project/libcxx/include/__ranges/rend.h (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583)
181ad6265SDimitry Andric // -*- C++ -*-
281ad6265SDimitry Andric //===----------------------------------------------------------------------===//
381ad6265SDimitry Andric //
481ad6265SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
581ad6265SDimitry Andric // See https://llvm.org/LICENSE.txt for license information.
681ad6265SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
781ad6265SDimitry Andric //
881ad6265SDimitry Andric //===----------------------------------------------------------------------===//
9bdd1243dSDimitry Andric 
1081ad6265SDimitry Andric #ifndef _LIBCPP___RANGES_REND_H
1181ad6265SDimitry Andric #define _LIBCPP___RANGES_REND_H
1281ad6265SDimitry Andric 
1381ad6265SDimitry Andric #include <__concepts/class_or_enum.h>
1481ad6265SDimitry Andric #include <__concepts/same_as.h>
1581ad6265SDimitry Andric #include <__config>
1681ad6265SDimitry Andric #include <__iterator/concepts.h>
1781ad6265SDimitry Andric #include <__iterator/readable_traits.h>
1881ad6265SDimitry Andric #include <__iterator/reverse_iterator.h>
1981ad6265SDimitry Andric #include <__ranges/access.h>
2081ad6265SDimitry Andric #include <__ranges/rbegin.h>
2106c3fb27SDimitry Andric #include <__type_traits/decay.h>
2206c3fb27SDimitry Andric #include <__type_traits/is_reference.h>
2306c3fb27SDimitry Andric #include <__type_traits/remove_cvref.h>
2406c3fb27SDimitry Andric #include <__type_traits/remove_reference.h>
2581ad6265SDimitry Andric #include <__utility/auto_cast.h>
2681ad6265SDimitry Andric 
2781ad6265SDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
2881ad6265SDimitry Andric #  pragma GCC system_header
2981ad6265SDimitry Andric #endif
3081ad6265SDimitry Andric 
3181ad6265SDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD
3281ad6265SDimitry Andric 
3306c3fb27SDimitry Andric #if _LIBCPP_STD_VER >= 20
3481ad6265SDimitry Andric 
3581ad6265SDimitry Andric // [range.access.rend]
3681ad6265SDimitry Andric 
3781ad6265SDimitry Andric namespace ranges {
3881ad6265SDimitry Andric namespace __rend {
3981ad6265SDimitry Andric template <class _Tp>
40*0fca6ea1SDimitry Andric concept __member_rend = __can_borrow<_Tp> && requires(_Tp&& __t) {
4181ad6265SDimitry Andric   ranges::rbegin(__t);
4281ad6265SDimitry Andric   { _LIBCPP_AUTO_CAST(__t.rend()) } -> sentinel_for<decltype(ranges::rbegin(__t))>;
4381ad6265SDimitry Andric };
4481ad6265SDimitry Andric 
45*0fca6ea1SDimitry Andric void rend() = delete;
4681ad6265SDimitry Andric 
4781ad6265SDimitry Andric template <class _Tp>
4881ad6265SDimitry Andric concept __unqualified_rend =
49cb14a3feSDimitry Andric     !__member_rend<_Tp> && __can_borrow<_Tp> && __class_or_enum<remove_cvref_t<_Tp>> && requires(_Tp&& __t) {
5081ad6265SDimitry Andric       ranges::rbegin(__t);
5181ad6265SDimitry Andric       { _LIBCPP_AUTO_CAST(rend(__t)) } -> sentinel_for<decltype(ranges::rbegin(__t))>;
5281ad6265SDimitry Andric     };
5381ad6265SDimitry Andric 
5481ad6265SDimitry Andric template <class _Tp>
55cb14a3feSDimitry Andric concept __can_reverse = __can_borrow<_Tp> && !__member_rend<_Tp> && !__unqualified_rend<_Tp> && requires(_Tp&& __t) {
5681ad6265SDimitry Andric   { ranges::begin(__t) } -> same_as<decltype(ranges::end(__t))>;
5781ad6265SDimitry Andric   { ranges::begin(__t) } -> bidirectional_iterator;
5881ad6265SDimitry Andric };
5981ad6265SDimitry Andric 
6081ad6265SDimitry Andric class __fn {
6181ad6265SDimitry Andric public:
6281ad6265SDimitry Andric   template <class _Tp>
6381ad6265SDimitry Andric     requires __member_rend<_Tp>
6481ad6265SDimitry Andric   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
65cb14a3feSDimitry Andric       noexcept(noexcept(_LIBCPP_AUTO_CAST(__t.rend()))) {
6681ad6265SDimitry Andric     return _LIBCPP_AUTO_CAST(__t.rend());
6781ad6265SDimitry Andric   }
6881ad6265SDimitry Andric 
6981ad6265SDimitry Andric   template <class _Tp>
7081ad6265SDimitry Andric     requires __unqualified_rend<_Tp>
7181ad6265SDimitry Andric   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
72cb14a3feSDimitry Andric       noexcept(noexcept(_LIBCPP_AUTO_CAST(rend(__t)))) {
7381ad6265SDimitry Andric     return _LIBCPP_AUTO_CAST(rend(__t));
7481ad6265SDimitry Andric   }
7581ad6265SDimitry Andric 
7681ad6265SDimitry Andric   template <class _Tp>
7781ad6265SDimitry Andric     requires __can_reverse<_Tp>
7881ad6265SDimitry Andric   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
79cb14a3feSDimitry Andric       noexcept(noexcept(ranges::begin(__t))) {
8081ad6265SDimitry Andric     return std::make_reverse_iterator(ranges::begin(__t));
8181ad6265SDimitry Andric   }
8281ad6265SDimitry Andric 
8381ad6265SDimitry Andric   void operator()(auto&&) const = delete;
8481ad6265SDimitry Andric };
8581ad6265SDimitry Andric } // namespace __rend
8681ad6265SDimitry Andric 
8781ad6265SDimitry Andric inline namespace __cpo {
8881ad6265SDimitry Andric inline constexpr auto rend = __rend::__fn{};
8981ad6265SDimitry Andric } // namespace __cpo
9081ad6265SDimitry Andric } // namespace ranges
9181ad6265SDimitry Andric 
9281ad6265SDimitry Andric // [range.access.crend]
9381ad6265SDimitry Andric 
9481ad6265SDimitry Andric namespace ranges {
9581ad6265SDimitry Andric namespace __crend {
9681ad6265SDimitry Andric struct __fn {
9781ad6265SDimitry Andric   template <class _Tp>
9881ad6265SDimitry Andric     requires is_lvalue_reference_v<_Tp&&>
99cb14a3feSDimitry Andric   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
10081ad6265SDimitry Andric       noexcept(noexcept(ranges::rend(static_cast<const remove_reference_t<_Tp>&>(__t))))
101cb14a3feSDimitry Andric           -> decltype(ranges::rend(static_cast<const remove_reference_t<_Tp>&>(__t))) {
102cb14a3feSDimitry Andric     return ranges::rend(static_cast<const remove_reference_t<_Tp>&>(__t));
103cb14a3feSDimitry Andric   }
10481ad6265SDimitry Andric 
10581ad6265SDimitry Andric   template <class _Tp>
10681ad6265SDimitry Andric     requires is_rvalue_reference_v<_Tp&&>
107*0fca6ea1SDimitry Andric   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const noexcept(
108*0fca6ea1SDimitry Andric       noexcept(ranges::rend(static_cast<const _Tp&&>(__t)))) -> decltype(ranges::rend(static_cast<const _Tp&&>(__t))) {
109cb14a3feSDimitry Andric     return ranges::rend(static_cast<const _Tp&&>(__t));
110cb14a3feSDimitry Andric   }
11181ad6265SDimitry Andric };
11281ad6265SDimitry Andric } // namespace __crend
11381ad6265SDimitry Andric 
11481ad6265SDimitry Andric inline namespace __cpo {
11581ad6265SDimitry Andric inline constexpr auto crend = __crend::__fn{};
11681ad6265SDimitry Andric } // namespace __cpo
11781ad6265SDimitry Andric } // namespace ranges
11881ad6265SDimitry Andric 
11906c3fb27SDimitry Andric #endif // _LIBCPP_STD_VER >= 20
12081ad6265SDimitry Andric 
12181ad6265SDimitry Andric _LIBCPP_END_NAMESPACE_STD
12281ad6265SDimitry Andric 
12381ad6265SDimitry Andric #endif // _LIBCPP___RANGES_REND_H
124