78 lines · c
1//===----------------------------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef _LIBCPP___ALGORITHM_RANGES_REVERSE_H10#define _LIBCPP___ALGORITHM_RANGES_REVERSE_H11 12#include <__config>13#include <__iterator/concepts.h>14#include <__iterator/iter_swap.h>15#include <__iterator/next.h>16#include <__iterator/permutable.h>17#include <__ranges/access.h>18#include <__ranges/concepts.h>19#include <__ranges/dangling.h>20 21#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)22# pragma GCC system_header23#endif24 25#if _LIBCPP_STD_VER >= 2026 27_LIBCPP_BEGIN_NAMESPACE_STD28 29namespace ranges {30struct __reverse {31 template <bidirectional_iterator _Iter, sentinel_for<_Iter> _Sent>32 requires permutable<_Iter>33 _LIBCPP_HIDE_FROM_ABI constexpr _Iter operator()(_Iter __first, _Sent __last) const {34 if constexpr (random_access_iterator<_Iter>) {35 if (__first == __last)36 return __first;37 38 auto __end = ranges::next(__first, __last);39 auto __ret = __end;40 41 while (__first < --__end) {42 ranges::iter_swap(__first, __end);43 ++__first;44 }45 return __ret;46 } else {47 auto __end = ranges::next(__first, __last);48 auto __ret = __end;49 50 while (__first != __end) {51 if (__first == --__end)52 break;53 54 ranges::iter_swap(__first, __end);55 ++__first;56 }57 return __ret;58 }59 }60 61 template <bidirectional_range _Range>62 requires permutable<iterator_t<_Range>>63 _LIBCPP_HIDE_FROM_ABI constexpr borrowed_iterator_t<_Range> operator()(_Range&& __range) const {64 return (*this)(ranges::begin(__range), ranges::end(__range));65 }66};67 68inline namespace __cpo {69inline constexpr auto reverse = __reverse{};70} // namespace __cpo71} // namespace ranges72 73_LIBCPP_END_NAMESPACE_STD74 75#endif // _LIBCPP_STD_VER >= 2076 77#endif // _LIBCPP___ALGORITHM_RANGES_REVERSE_H78