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-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef _LIBCPP___ALGORITHM_RANGES_SHIFT_RIGHT_H
10#define _LIBCPP___ALGORITHM_RANGES_SHIFT_RIGHT_H
11
12#include <__algorithm/iterator_operations.h>
13#include <__algorithm/shift_right.h>
14#include <__config>
15#include <__iterator/concepts.h>
16#include <__iterator/distance.h>
17#include <__iterator/incrementable_traits.h>
18#include <__iterator/permutable.h>
19#include <__ranges/access.h>
20#include <__ranges/concepts.h>
21#include <__ranges/subrange.h>
22#include <__utility/move.h>
23
24#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
25# pragma GCC system_header
26#endif
27
28_LIBCPP_PUSH_MACROS
29#include <__undef_macros>
30
31_LIBCPP_BEGIN_NAMESPACE_STD
32
33#if _LIBCPP_STD_VER >= 23
34
35namespace ranges {
36namespace __shift_right {
37
38struct __fn {
39 template <permutable _Iter, sentinel_for<_Iter> _Sent>
40 static constexpr subrange<_Iter> operator()(_Iter __first, _Sent __last, iter_difference_t<_Iter> __n) {
41 auto __ret = std::__shift_right<_RangeAlgPolicy>(std::move(__first), std::move(__last), std::move(__n));
42 return {std::move(__ret.first), std::move(__ret.second)};
43 }
44
45 template <forward_range _Range>
46 requires permutable<iterator_t<_Range>>
47 static constexpr borrowed_subrange_t<_Range> operator()(_Range&& __range, range_difference_t<_Range> __n) {
48 if constexpr (sized_range<_Range>) {
49 if (__n >= ranges::distance(__range)) {
50 auto __iter = ranges::begin(__range);
51 auto __end = ranges::end(__range);
52 ranges::advance(__iter, __end);
53 return {__iter, std::move(__iter)};
54 }
55 }
56
57 auto __ret = std::__shift_right<_RangeAlgPolicy>(ranges::begin(__range), ranges::end(__range), std::move(__n));
58 return {std::move(__ret.first), std::move(__ret.second)};
59 }
60};
61} // namespace __shift_right
62
63inline namespace __cpo {
64inline constexpr auto shift_right = __shift_right::__fn{};
65} // namespace __cpo
66} // namespace ranges
67
68#endif // _LIBCPP_STD_VER >= 23
69
70_LIBCPP_END_NAMESPACE_STD
71
72_LIBCPP_POP_MACROS
73
74#endif // _LIBCPP___ALGORITHM_RANGES_SHIFT_RIGHT_H
75