| //===----------------------------------------------------------------------===// |
| // |
| // 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___ALGORITHM_RANGES_REVERSE_H |
| #define _LIBCPP___ALGORITHM_RANGES_REVERSE_H |
| |
| #include <__config> |
| #include <__iterator/concepts.h> |
| #include <__iterator/iter_swap.h> |
| #include <__iterator/next.h> |
| #include <__iterator/permutable.h> |
| #include <__ranges/access.h> |
| #include <__ranges/concepts.h> |
| #include <__ranges/dangling.h> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| # pragma GCC system_header |
| #endif |
| |
| #if _LIBCPP_STD_VER >= 20 |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| namespace ranges { |
| namespace __reverse { |
| struct __fn { |
| |
| template <bidirectional_iterator _Iter, sentinel_for<_Iter> _Sent> |
| requires permutable<_Iter> |
| _LIBCPP_HIDE_FROM_ABI constexpr |
| _Iter operator()(_Iter __first, _Sent __last) const { |
| if constexpr (random_access_iterator<_Iter>) { |
| if (__first == __last) |
| return __first; |
| |
| auto __end = ranges::next(__first, __last); |
| auto __ret = __end; |
| |
| while (__first < --__end) { |
| ranges::iter_swap(__first, __end); |
| ++__first; |
| } |
| return __ret; |
| } else { |
| auto __end = ranges::next(__first, __last); |
| auto __ret = __end; |
| |
| while (__first != __end) { |
| if (__first == --__end) |
| break; |
| |
| ranges::iter_swap(__first, __end); |
| ++__first; |
| } |
| return __ret; |
| } |
| } |
| |
| template <bidirectional_range _Range> |
| requires permutable<iterator_t<_Range>> |
| _LIBCPP_HIDE_FROM_ABI constexpr |
| borrowed_iterator_t<_Range> operator()(_Range&& __range) const { |
| return (*this)(ranges::begin(__range), ranges::end(__range)); |
| } |
| |
| }; |
| } // namespace __reverse |
| |
| inline namespace __cpo { |
| inline constexpr auto reverse = __reverse::__fn{}; |
| } // namespace __cpo |
| } // namespace ranges |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| #endif // _LIBCPP_STD_VER >= 20 |
| |
| #endif // _LIBCPP___ALGORITHM_RANGES_REVERSE_H |