xref: /freebsd/contrib/llvm-project/libcxx/include/__algorithm/ranges_search.h (revision a2fda816eb054d5873be223ef2461741dfcc253c)
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_H
10  #define _LIBCPP___ALGORITHM_RANGES_SEARCH_H
11  
12  #include <__algorithm/iterator_operations.h>
13  #include <__algorithm/search.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/indirectly_comparable.h>
21  #include <__ranges/access.h>
22  #include <__ranges/concepts.h>
23  #include <__ranges/size.h>
24  #include <__ranges/subrange.h>
25  #include <__utility/pair.h>
26  
27  #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
28  #  pragma GCC system_header
29  #endif
30  
31  #if _LIBCPP_STD_VER >= 20
32  
33  _LIBCPP_BEGIN_NAMESPACE_STD
34  
35  namespace ranges {
36  namespace __search {
37  struct __fn {
38    template <class _Iter1, class _Sent1, class _Iter2, class _Sent2, class _Pred, class _Proj1, class _Proj2>
39    _LIBCPP_HIDE_FROM_ABI static constexpr subrange<_Iter1> __ranges_search_impl(
40        _Iter1 __first1,
41        _Sent1 __last1,
42        _Iter2 __first2,
43        _Sent2 __last2,
44        _Pred& __pred,
45        _Proj1& __proj1,
46        _Proj2& __proj2) {
47      if constexpr (sized_sentinel_for<_Sent2, _Iter2>) {
48        auto __size2 = ranges::distance(__first2, __last2);
49        if (__size2 == 0)
50          return {__first1, __first1};
51  
52        if constexpr (sized_sentinel_for<_Sent1, _Iter1>) {
53          auto __size1 = ranges::distance(__first1, __last1);
54          if (__size1 < __size2) {
55            ranges::advance(__first1, __last1);
56            return {__first1, __first1};
57          }
58  
59          if constexpr (random_access_iterator<_Iter1> && random_access_iterator<_Iter2>) {
60            auto __ret = std::__search_random_access_impl<_RangeAlgPolicy>(
61                __first1, __last1, __first2, __last2, __pred, __proj1, __proj2, __size1, __size2);
62            return {__ret.first, __ret.second};
63          }
64        }
65      }
66  
67      auto __ret =
68          std::__search_forward_impl<_RangeAlgPolicy>(__first1, __last1, __first2, __last2, __pred, __proj1, __proj2);
69      return {__ret.first, __ret.second};
70    }
71  
72    template <forward_iterator _Iter1,
73              sentinel_for<_Iter1> _Sent1,
74              forward_iterator _Iter2,
75              sentinel_for<_Iter2> _Sent2,
76              class _Pred  = ranges::equal_to,
77              class _Proj1 = identity,
78              class _Proj2 = identity>
79      requires indirectly_comparable<_Iter1, _Iter2, _Pred, _Proj1, _Proj2>
80    _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr subrange<_Iter1> operator()(
81        _Iter1 __first1,
82        _Sent1 __last1,
83        _Iter2 __first2,
84        _Sent2 __last2,
85        _Pred __pred   = {},
86        _Proj1 __proj1 = {},
87        _Proj2 __proj2 = {}) const {
88      return __ranges_search_impl(__first1, __last1, __first2, __last2, __pred, __proj1, __proj2);
89    }
90  
91    template <forward_range _Range1,
92              forward_range _Range2,
93              class _Pred  = ranges::equal_to,
94              class _Proj1 = identity,
95              class _Proj2 = identity>
96      requires indirectly_comparable<iterator_t<_Range1>, iterator_t<_Range2>, _Pred, _Proj1, _Proj2>
97    _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr borrowed_subrange_t<_Range1> operator()(
98        _Range1&& __range1, _Range2&& __range2, _Pred __pred = {}, _Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const {
99      auto __first1 = ranges::begin(__range1);
100      if constexpr (sized_range<_Range2>) {
101        auto __size2 = ranges::size(__range2);
102        if (__size2 == 0)
103          return {__first1, __first1};
104        if constexpr (sized_range<_Range1>) {
105          auto __size1 = ranges::size(__range1);
106          if (__size1 < __size2) {
107            ranges::advance(__first1, ranges::end(__range1));
108            return {__first1, __first1};
109          }
110        }
111      }
112  
113      return __ranges_search_impl(
114          ranges::begin(__range1),
115          ranges::end(__range1),
116          ranges::begin(__range2),
117          ranges::end(__range2),
118          __pred,
119          __proj1,
120          __proj2);
121    }
122  };
123  } // namespace __search
124  
125  inline namespace __cpo {
126  inline constexpr auto search = __search::__fn{};
127  } // namespace __cpo
128  } // namespace ranges
129  
130  _LIBCPP_END_NAMESPACE_STD
131  
132  #endif // _LIBCPP_STD_VER >= 20
133  
134  #endif // _LIBCPP___ALGORITHM_RANGES_SEARCH_H
135