181ad6265SDimitry Andric //===----------------------------------------------------------------------===// 281ad6265SDimitry Andric // 381ad6265SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 481ad6265SDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 581ad6265SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 681ad6265SDimitry Andric // 781ad6265SDimitry Andric //===----------------------------------------------------------------------===// 881ad6265SDimitry Andric 981ad6265SDimitry Andric #ifndef _LIBCPP___ALGORITHM_RANGES_REVERSE_H 1081ad6265SDimitry Andric #define _LIBCPP___ALGORITHM_RANGES_REVERSE_H 1181ad6265SDimitry Andric 1281ad6265SDimitry Andric #include <__config> 1381ad6265SDimitry Andric #include <__iterator/concepts.h> 1481ad6265SDimitry Andric #include <__iterator/iter_swap.h> 1581ad6265SDimitry Andric #include <__iterator/next.h> 1681ad6265SDimitry Andric #include <__iterator/permutable.h> 1781ad6265SDimitry Andric #include <__ranges/access.h> 1881ad6265SDimitry Andric #include <__ranges/concepts.h> 1981ad6265SDimitry Andric #include <__ranges/dangling.h> 2081ad6265SDimitry Andric 2181ad6265SDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 2281ad6265SDimitry Andric # pragma GCC system_header 2381ad6265SDimitry Andric #endif 2481ad6265SDimitry Andric 25*06c3fb27SDimitry Andric #if _LIBCPP_STD_VER >= 20 2681ad6265SDimitry Andric 2781ad6265SDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD 2881ad6265SDimitry Andric 2981ad6265SDimitry Andric namespace ranges { 3081ad6265SDimitry Andric namespace __reverse { 3181ad6265SDimitry Andric struct __fn { 3281ad6265SDimitry Andric template <bidirectional_iterator _Iter, sentinel_for<_Iter> _Sent> 3381ad6265SDimitry Andric requires permutable<_Iter> operator__fn34*06c3fb27SDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr _Iter operator()(_Iter __first, _Sent __last) const { 3581ad6265SDimitry Andric if constexpr (random_access_iterator<_Iter>) { 3681ad6265SDimitry Andric if (__first == __last) 3781ad6265SDimitry Andric return __first; 3881ad6265SDimitry Andric 3981ad6265SDimitry Andric auto __end = ranges::next(__first, __last); 4081ad6265SDimitry Andric auto __ret = __end; 4181ad6265SDimitry Andric 4281ad6265SDimitry Andric while (__first < --__end) { 4381ad6265SDimitry Andric ranges::iter_swap(__first, __end); 4481ad6265SDimitry Andric ++__first; 4581ad6265SDimitry Andric } 4681ad6265SDimitry Andric return __ret; 4781ad6265SDimitry Andric } else { 4881ad6265SDimitry Andric auto __end = ranges::next(__first, __last); 4981ad6265SDimitry Andric auto __ret = __end; 5081ad6265SDimitry Andric 5181ad6265SDimitry Andric while (__first != __end) { 5281ad6265SDimitry Andric if (__first == --__end) 5381ad6265SDimitry Andric break; 5481ad6265SDimitry Andric 5581ad6265SDimitry Andric ranges::iter_swap(__first, __end); 5681ad6265SDimitry Andric ++__first; 5781ad6265SDimitry Andric } 5881ad6265SDimitry Andric return __ret; 5981ad6265SDimitry Andric } 6081ad6265SDimitry Andric } 6181ad6265SDimitry Andric 6281ad6265SDimitry Andric template <bidirectional_range _Range> 6381ad6265SDimitry Andric requires permutable<iterator_t<_Range>> operator__fn64*06c3fb27SDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr borrowed_iterator_t<_Range> operator()(_Range&& __range) const { 6581ad6265SDimitry Andric return (*this)(ranges::begin(__range), ranges::end(__range)); 6681ad6265SDimitry Andric } 6781ad6265SDimitry Andric }; 6881ad6265SDimitry Andric } // namespace __reverse 6981ad6265SDimitry Andric 7081ad6265SDimitry Andric inline namespace __cpo { 7181ad6265SDimitry Andric inline constexpr auto reverse = __reverse::__fn{}; 7281ad6265SDimitry Andric } // namespace __cpo 7381ad6265SDimitry Andric } // namespace ranges 7481ad6265SDimitry Andric 7581ad6265SDimitry Andric _LIBCPP_END_NAMESPACE_STD 7681ad6265SDimitry Andric 77*06c3fb27SDimitry Andric #endif // _LIBCPP_STD_VER >= 20 7881ad6265SDimitry Andric 7981ad6265SDimitry Andric #endif // _LIBCPP___ALGORITHM_RANGES_REVERSE_H 80