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// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___RANGES_REND_H
#define _LIBCPP___RANGES_REND_H
#include <__concepts/class_or_enum.h>
#include <__concepts/same_as.h>
#include <__config>
#include <__iterator/concepts.h>
#include <__iterator/readable_traits.h>
#include <__iterator/reverse_iterator.h>
#include <__ranges/access.h>
#include <__ranges/rbegin.h>
#include <__type_traits/decay.h>
#include <__type_traits/is_reference.h>
#include <__type_traits/remove_cvref.h>
#include <__type_traits/remove_reference.h>
#include <__utility/auto_cast.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER >= 20
// [range.access.rend]
namespace ranges {
namespace __rend {
template <class _Tp>
concept __member_rend = __can_borrow<_Tp> && requires(_Tp&& __t) {
ranges::rbegin(__t);
{ _LIBCPP_AUTO_CAST(__t.rend()) } -> sentinel_for<decltype(ranges::rbegin(__t))>;
};
void rend() = delete;
template <class _Tp>
concept __unqualified_rend =
!__member_rend<_Tp> && __can_borrow<_Tp> && __class_or_enum<remove_cvref_t<_Tp>> && requires(_Tp&& __t) {
ranges::rbegin(__t);
{ _LIBCPP_AUTO_CAST(rend(__t)) } -> sentinel_for<decltype(ranges::rbegin(__t))>;
};
template <class _Tp>
concept __can_reverse = __can_borrow<_Tp> && !__member_rend<_Tp> && !__unqualified_rend<_Tp> && requires(_Tp&& __t) {
{ ranges::begin(__t) } -> same_as<decltype(ranges::end(__t))>;
{ ranges::begin(__t) } -> bidirectional_iterator;
};
class __fn {
public:
template <class _Tp>
requires __member_rend<_Tp>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
noexcept(noexcept(_LIBCPP_AUTO_CAST(__t.rend()))) {
return _LIBCPP_AUTO_CAST(__t.rend());
}
template <class _Tp>
requires __unqualified_rend<_Tp>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
noexcept(noexcept(_LIBCPP_AUTO_CAST(rend(__t)))) {
return _LIBCPP_AUTO_CAST(rend(__t));
}
template <class _Tp>
requires __can_reverse<_Tp>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
noexcept(noexcept(ranges::begin(__t))) {
return std::make_reverse_iterator(ranges::begin(__t));
}
void operator()(auto&&) const = delete;
};
} // namespace __rend
inline namespace __cpo {
inline constexpr auto rend = __rend::__fn{};
} // namespace __cpo
} // namespace ranges
// [range.access.crend]
namespace ranges {
namespace __crend {
struct __fn {
template <class _Tp>
requires is_lvalue_reference_v<_Tp&&>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
noexcept(noexcept(ranges::rend(static_cast<const remove_reference_t<_Tp>&>(__t))))
-> decltype(ranges::rend(static_cast<const remove_reference_t<_Tp>&>(__t))) {
return ranges::rend(static_cast<const remove_reference_t<_Tp>&>(__t));
}
template <class _Tp>
requires is_rvalue_reference_v<_Tp&&>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
noexcept(noexcept(ranges::rend(static_cast<const _Tp&&>(__t))))
-> decltype(ranges::rend(static_cast<const _Tp&&>(__t))) {
return ranges::rend(static_cast<const _Tp&&>(__t));
}
};
} // namespace __crend
inline namespace __cpo {
inline constexpr auto crend = __crend::__fn{};
} // namespace __cpo
} // namespace ranges
#endif // _LIBCPP_STD_VER >= 20
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___RANGES_REND_H