1*4bdff4beSrobert //===----------------------------------------------------------------------===// 2*4bdff4beSrobert // 3*4bdff4beSrobert // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4*4bdff4beSrobert // See https://llvm.org/LICENSE.txt for license information. 5*4bdff4beSrobert // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6*4bdff4beSrobert // 7*4bdff4beSrobert //===----------------------------------------------------------------------===// 8*4bdff4beSrobert 9*4bdff4beSrobert #ifndef _LIBCPP___ALGORITHM_RANGES_REVERSE_H 10*4bdff4beSrobert #define _LIBCPP___ALGORITHM_RANGES_REVERSE_H 11*4bdff4beSrobert 12*4bdff4beSrobert #include <__config> 13*4bdff4beSrobert #include <__iterator/concepts.h> 14*4bdff4beSrobert #include <__iterator/iter_swap.h> 15*4bdff4beSrobert #include <__iterator/next.h> 16*4bdff4beSrobert #include <__iterator/permutable.h> 17*4bdff4beSrobert #include <__ranges/access.h> 18*4bdff4beSrobert #include <__ranges/concepts.h> 19*4bdff4beSrobert #include <__ranges/dangling.h> 20*4bdff4beSrobert 21*4bdff4beSrobert #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 22*4bdff4beSrobert # pragma GCC system_header 23*4bdff4beSrobert #endif 24*4bdff4beSrobert 25*4bdff4beSrobert #if _LIBCPP_STD_VER > 17 26*4bdff4beSrobert 27*4bdff4beSrobert _LIBCPP_BEGIN_NAMESPACE_STD 28*4bdff4beSrobert 29*4bdff4beSrobert namespace ranges { 30*4bdff4beSrobert namespace __reverse { 31*4bdff4beSrobert struct __fn { 32*4bdff4beSrobert 33*4bdff4beSrobert template <bidirectional_iterator _Iter, sentinel_for<_Iter> _Sent> 34*4bdff4beSrobert requires permutable<_Iter> 35*4bdff4beSrobert _LIBCPP_HIDE_FROM_ABI constexpr operator__fn36*4bdff4beSrobert _Iter operator()(_Iter __first, _Sent __last) const { 37*4bdff4beSrobert if constexpr (random_access_iterator<_Iter>) { 38*4bdff4beSrobert if (__first == __last) 39*4bdff4beSrobert return __first; 40*4bdff4beSrobert 41*4bdff4beSrobert auto __end = ranges::next(__first, __last); 42*4bdff4beSrobert auto __ret = __end; 43*4bdff4beSrobert 44*4bdff4beSrobert while (__first < --__end) { 45*4bdff4beSrobert ranges::iter_swap(__first, __end); 46*4bdff4beSrobert ++__first; 47*4bdff4beSrobert } 48*4bdff4beSrobert return __ret; 49*4bdff4beSrobert } else { 50*4bdff4beSrobert auto __end = ranges::next(__first, __last); 51*4bdff4beSrobert auto __ret = __end; 52*4bdff4beSrobert 53*4bdff4beSrobert while (__first != __end) { 54*4bdff4beSrobert if (__first == --__end) 55*4bdff4beSrobert break; 56*4bdff4beSrobert 57*4bdff4beSrobert ranges::iter_swap(__first, __end); 58*4bdff4beSrobert ++__first; 59*4bdff4beSrobert } 60*4bdff4beSrobert return __ret; 61*4bdff4beSrobert } 62*4bdff4beSrobert } 63*4bdff4beSrobert 64*4bdff4beSrobert template <bidirectional_range _Range> 65*4bdff4beSrobert requires permutable<iterator_t<_Range>> 66*4bdff4beSrobert _LIBCPP_HIDE_FROM_ABI constexpr operator__fn67*4bdff4beSrobert borrowed_iterator_t<_Range> operator()(_Range&& __range) const { 68*4bdff4beSrobert return (*this)(ranges::begin(__range), ranges::end(__range)); 69*4bdff4beSrobert } 70*4bdff4beSrobert 71*4bdff4beSrobert }; 72*4bdff4beSrobert } // namespace __reverse 73*4bdff4beSrobert 74*4bdff4beSrobert inline namespace __cpo { 75*4bdff4beSrobert inline constexpr auto reverse = __reverse::__fn{}; 76*4bdff4beSrobert } // namespace __cpo 77*4bdff4beSrobert } // namespace ranges 78*4bdff4beSrobert 79*4bdff4beSrobert _LIBCPP_END_NAMESPACE_STD 80*4bdff4beSrobert 81*4bdff4beSrobert #endif // _LIBCPP_STD_VER > 17 82*4bdff4beSrobert 83*4bdff4beSrobert #endif // _LIBCPP___ALGORITHM_RANGES_REVERSE_H 84