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 {
42namespace __search_n {
43struct __fn {
44  template <class _Iter1, class _Sent1, class _SizeT, class _Type, class _Pred, class _Proj>
45  _LIBCPP_HIDE_FROM_ABI static constexpr subrange<_Iter1> __ranges_search_n_impl(
46      _Iter1 __first, _Sent1 __last, _SizeT __count, const _Type& __value, _Pred& __pred, _Proj& __proj) {
47    if (__count == 0)
48      return {__first, __first};
49
50    if constexpr (sized_sentinel_for<_Sent1, _Iter1>) {
51      auto __size = ranges::distance(__first, __last);
52      if (__size < __count) {
53        ranges::advance(__first, __last);
54        return {__first, __first};
55      }
56
57      if constexpr (random_access_iterator<_Iter1>) {
58        auto __ret = std::__search_n_random_access_impl<_RangeAlgPolicy>(
59            __first, __last, __count, __value, __pred, __proj, __size);
60        return {std::move(__ret.first), std::move(__ret.second)};
61      }
62    }
63
64    auto __ret = std::__search_n_forward_impl<_RangeAlgPolicy>(__first, __last, __count, __value, __pred, __proj);
65    return {std::move(__ret.first), std::move(__ret.second)};
66  }
67
68  template <forward_iterator _Iter,
69            sentinel_for<_Iter> _Sent,
70            class _Type,
71            class _Pred = ranges::equal_to,
72            class _Proj = identity>
73    requires indirectly_comparable<_Iter, const _Type*, _Pred, _Proj>
74  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr subrange<_Iter>
75  operator()(_Iter __first,
76             _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 borrowed_subrange_t<_Range> operator()(
87      _Range&& __range, range_difference_t<_Range> __count, const _Type& __value, _Pred __pred = {}, _Proj __proj = {})
88      const {
89    auto __first = ranges::begin(__range);
90    if (__count <= 0)
91      return {__first, __first};
92    if constexpr (sized_range<_Range>) {
93      auto __size1 = ranges::size(__range);
94      if (__size1 < static_cast<range_size_t<_Range>>(__count)) {
95        ranges::advance(__first, ranges::end(__range));
96        return {__first, __first};
97      }
98    }
99
100    return __ranges_search_n_impl(ranges::begin(__range), ranges::end(__range), __count, __value, __pred, __proj);
101  }
102};
103} // namespace __search_n
104
105inline namespace __cpo {
106inline constexpr auto search_n = __search_n::__fn{};
107} // namespace __cpo
108} // namespace ranges
109
110_LIBCPP_END_NAMESPACE_STD
111
112#endif // _LIBCPP_STD_VER >= 20
113
114_LIBCPP_POP_MACROS
115
116#endif // _LIBCPP___ALGORITHM_RANGES_SEARCH_N_H
117