master
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_SEARCH_N_H
10#define _LIBCPP___ALGORITHM_RANGES_SEARCH_N_H
11
12#include <__algorithm/iterator_operations.h>
13#include <__algorithm/search_n.h>
14#include <__config>
15#include <__functional/identity.h>
16#include <__functional/ranges_operations.h>
17#include <__iterator/advance.h>
18#include <__iterator/concepts.h>
19#include <__iterator/distance.h>
20#include <__iterator/incrementable_traits.h>
21#include <__iterator/indirectly_comparable.h>
22#include <__iterator/iterator_traits.h>
23#include <__ranges/access.h>
24#include <__ranges/concepts.h>
25#include <__ranges/size.h>
26#include <__ranges/subrange.h>
27#include <__utility/move.h>
28#include <__utility/pair.h>
29
30#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
31# pragma GCC system_header
32#endif
33
34_LIBCPP_PUSH_MACROS
35#include <__undef_macros>
36
37#if _LIBCPP_STD_VER >= 20
38
39_LIBCPP_BEGIN_NAMESPACE_STD
40
41namespace ranges {
42struct __search_n {
43 template <class _Iter1, class _Sent1, class _SizeT, class _Type, class _Pred, class _Proj>
44 _LIBCPP_HIDE_FROM_ABI static constexpr subrange<_Iter1> __ranges_search_n_impl(
45 _Iter1 __first, _Sent1 __last, _SizeT __count, const _Type& __value, _Pred& __pred, _Proj& __proj) {
46 if (__count == 0)
47 return {__first, __first};
48
49 if constexpr (sized_sentinel_for<_Sent1, _Iter1>) {
50 auto __size = ranges::distance(__first, __last);
51 if (__size < __count) {
52 ranges::advance(__first, __last);
53 return {__first, __first};
54 }
55
56 if constexpr (random_access_iterator<_Iter1>) {
57 auto __ret = std::__search_n_random_access_impl<_RangeAlgPolicy>(
58 __first, __last, __count, __value, __pred, __proj, __size);
59 return {std::move(__ret.first), std::move(__ret.second)};
60 }
61 }
62
63 auto __ret = std::__search_n_forward_impl<_RangeAlgPolicy>(__first, __last, __count, __value, __pred, __proj);
64 return {std::move(__ret.first), std::move(__ret.second)};
65 }
66
67 template <forward_iterator _Iter,
68 sentinel_for<_Iter> _Sent,
69 class _Type,
70 class _Pred = ranges::equal_to,
71 class _Proj = identity>
72 requires indirectly_comparable<_Iter, const _Type*, _Pred, _Proj>
73 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr subrange<_Iter>
74 operator()(_Iter __first,
75 _Sent __last,
76 iter_difference_t<_Iter> __count,
77 const _Type& __value,
78 _Pred __pred = {},
79 _Proj __proj = _Proj{}) const {
80 return __ranges_search_n_impl(__first, __last, __count, __value, __pred, __proj);
81 }
82
83 template <forward_range _Range, class _Type, class _Pred = ranges::equal_to, class _Proj = identity>
84 requires indirectly_comparable<iterator_t<_Range>, const _Type*, _Pred, _Proj>
85 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr borrowed_subrange_t<_Range> operator()(
86 _Range&& __range, range_difference_t<_Range> __count, const _Type& __value, _Pred __pred = {}, _Proj __proj = {})
87 const {
88 auto __first = ranges::begin(__range);
89 if (__count <= 0)
90 return {__first, __first};
91 if constexpr (sized_range<_Range>) {
92 auto __size1 = ranges::size(__range);
93 if (__size1 < static_cast<range_size_t<_Range>>(__count)) {
94 ranges::advance(__first, ranges::end(__range));
95 return {__first, __first};
96 }
97 }
98
99 return __ranges_search_n_impl(ranges::begin(__range), ranges::end(__range), __count, __value, __pred, __proj);
100 }
101};
102
103inline namespace __cpo {
104inline constexpr auto search_n = __search_n{};
105} // namespace __cpo
106} // namespace ranges
107
108_LIBCPP_END_NAMESPACE_STD
109
110#endif // _LIBCPP_STD_VER >= 20
111
112_LIBCPP_POP_MACROS
113
114#endif // _LIBCPP___ALGORITHM_RANGES_SEARCH_N_H