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 
26 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
27 #  pragma GCC system_header
28 #endif
29 
30 #if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
31 
32 _LIBCPP_BEGIN_NAMESPACE_STD
33 
34 namespace ranges {
35 namespace __search {
36 struct __fn {
37   template <class _Iter1, class _Sent1, class _Iter2, class _Sent2, class _Pred, class _Proj1, class _Proj2>
38   _LIBCPP_HIDE_FROM_ABI static constexpr subrange<_Iter1> __ranges_search_impl(
39       _Iter1 __first1,
40       _Sent1 __last1,
41       _Iter2 __first2,
42       _Sent2 __last2,
43       _Pred& __pred,
44       _Proj1& __proj1,
45       _Proj2& __proj2) {
46     if constexpr (sized_sentinel_for<_Sent2, _Iter2>) {
47       auto __size2 = ranges::distance(__first2, __last2);
48       if (__size2 == 0)
49         return {__first1, __first1};
50 
51       if constexpr (sized_sentinel_for<_Sent1, _Iter1>) {
52         auto __size1 = ranges::distance(__first1, __last1);
53         if (__size1 < __size2) {
54           ranges::advance(__first1, __last1);
55           return {__first1, __first1};
56         }
57 
58         if constexpr (random_access_iterator<_Iter1> && random_access_iterator<_Iter2>) {
59           auto __ret = std::__search_random_access_impl<_RangeAlgPolicy>(
60               __first1, __last1, __first2, __last2, __pred, __proj1, __proj2, __size1, __size2);
61           return {__ret.first, __ret.second};
62         }
63       }
64     }
65 
66     auto __ret =
67         std::__search_forward_impl<_RangeAlgPolicy>(__first1, __last1, __first2, __last2, __pred, __proj1, __proj2);
68     return {__ret.first, __ret.second};
69   }
70 
71   template <forward_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
72             forward_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
73             class _Pred = ranges::equal_to,
74             class _Proj1 = identity,
75             class _Proj2 = identity>
76     requires indirectly_comparable<_Iter1, _Iter2, _Pred, _Proj1, _Proj2>
77   _LIBCPP_HIDE_FROM_ABI constexpr
78   subrange<_Iter1> operator()(_Iter1 __first1, _Sent1 __last1,
79                               _Iter2 __first2, _Sent2 __last2,
80                               _Pred __pred = {},
81                               _Proj1 __proj1 = {},
82                               _Proj2 __proj2 = {}) const {
83     return __ranges_search_impl(__first1, __last1, __first2, __last2, __pred, __proj1, __proj2);
84   }
85 
86   template <forward_range _Range1,
87             forward_range _Range2,
88             class _Pred = ranges::equal_to,
89             class _Proj1 = identity,
90             class _Proj2 = identity>
91     requires indirectly_comparable<iterator_t<_Range1>, iterator_t<_Range2>, _Pred, _Proj1, _Proj2>
92   _LIBCPP_HIDE_FROM_ABI constexpr
93   borrowed_subrange_t<_Range1> operator()(_Range1&& __range1,
94                                           _Range2&& __range2,
95                                           _Pred __pred = {},
96                                           _Proj1 __proj1 = {},
97                                           _Proj2 __proj2 = {}) const {
98     auto __first1 = ranges::begin(__range1);
99     if constexpr (sized_range<_Range2>) {
100       auto __size2 = ranges::size(__range2);
101       if (__size2 == 0)
102         return {__first1, __first1};
103       if constexpr (sized_range<_Range1>) {
104         auto __size1 = ranges::size(__range1);
105         if (__size1 < __size2) {
106           ranges::advance(__first1, ranges::end(__range1));
107           return {__first1, __first1};
108         }
109       }
110     }
111 
112     return __ranges_search_impl(
113         ranges::begin(__range1),
114         ranges::end(__range1),
115         ranges::begin(__range2),
116         ranges::end(__range2),
117         __pred,
118         __proj1,
119         __proj2);
120   }
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 > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
133 
134 #endif // _LIBCPP___ALGORITHM_RANGES_SEARCH_H
135