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#if _LIBCPP_STD_VER > 17
35
36_LIBCPP_BEGIN_NAMESPACE_STD
37
38namespace ranges {
39namespace __search_n {
40struct __fn {
41
42  template <class _Iter1, class _Sent1, class _SizeT, class _Type, class _Pred, class _Proj>
43  _LIBCPP_HIDE_FROM_ABI static constexpr subrange<_Iter1> __ranges_search_n_impl(
44      _Iter1 __first, _Sent1 __last, _SizeT __count, const _Type& __value, _Pred& __pred, _Proj& __proj) {
45    if (__count == 0)
46      return {__first, __first};
47
48    if constexpr (sized_sentinel_for<_Sent1, _Iter1>) {
49      auto __size = ranges::distance(__first, __last);
50      if (__size < __count) {
51        ranges::advance(__first, __last);
52        return {__first, __first};
53      }
54
55      if constexpr (random_access_iterator<_Iter1>) {
56        auto __ret = std::__search_n_random_access_impl<_RangeAlgPolicy>(
57            __first, __last, __count, __value, __pred, __proj, __size);
58        return {std::move(__ret.first), std::move(__ret.second)};
59      }
60    }
61
62    auto __ret = std::__search_n_forward_impl<_RangeAlgPolicy>(__first, __last,
63                                                               __count,
64                                                               __value,
65                                                               __pred,
66                                                               __proj);
67    return {std::move(__ret.first), std::move(__ret.second)};
68  }
69
70  template <forward_iterator _Iter, sentinel_for<_Iter> _Sent,
71            class _Type,
72            class _Pred = ranges::equal_to,
73            class _Proj = identity>
74    requires indirectly_comparable<_Iter, const _Type*, _Pred, _Proj>
75  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr
76  subrange<_Iter> operator()(_Iter __first, _Sent __last,
77                             iter_difference_t<_Iter> __count,
78                             const _Type& __value,
79                             _Pred __pred = {},
80                             _Proj __proj = _Proj{}) const {
81    return __ranges_search_n_impl(__first, __last, __count, __value, __pred, __proj);
82  }
83
84  template <forward_range _Range, class _Type, class _Pred = ranges::equal_to, class _Proj = identity>
85    requires indirectly_comparable<iterator_t<_Range>, const _Type*, _Pred, _Proj>
86  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr
87  borrowed_subrange_t<_Range> operator()(_Range&& __range,
88                                         range_difference_t<_Range> __count,
89                                         const _Type& __value,
90                                         _Pred __pred = {},
91                                         _Proj __proj = {}) const {
92    auto __first = ranges::begin(__range);
93    if (__count <= 0)
94      return {__first, __first};
95    if constexpr (sized_range<_Range>) {
96      auto __size1 = ranges::size(__range);
97      if (__size1 < static_cast<range_size_t<_Range>>(__count)) {
98        ranges::advance(__first, ranges::end(__range));
99        return {__first, __first};
100      }
101    }
102
103    return __ranges_search_n_impl(ranges::begin(__range), ranges::end(__range), __count, __value, __pred, __proj);
104  }
105};
106} // namespace __search_n
107
108inline namespace __cpo {
109  inline constexpr auto search_n = __search_n::__fn{};
110} // namespace __cpo
111} // namespace ranges
112
113_LIBCPP_END_NAMESPACE_STD
114
115#endif // _LIBCPP_STD_VER > 17
116
117#endif // _LIBCPP___ALGORITHM_RANGES_SEARCH_N_H
118