1 | // -*- C++ -*- |
2 | //===----------------------------------------------------------------------===// |
3 | // |
4 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
5 | // See https://llvm.org/LICENSE.txt for license information. |
6 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
7 | // |
8 | //===----------------------------------------------------------------------===// |
9 | |
10 | #ifndef _LIBCPP___ALGORITHM_SEARCH_N_H |
11 | #define _LIBCPP___ALGORITHM_SEARCH_N_H |
12 | |
13 | #include <__algorithm/comp.h> |
14 | #include <__algorithm/iterator_operations.h> |
15 | #include <__config> |
16 | #include <__functional/identity.h> |
17 | #include <__iterator/advance.h> |
18 | #include <__iterator/concepts.h> |
19 | #include <__iterator/distance.h> |
20 | #include <__iterator/iterator_traits.h> |
21 | #include <__ranges/concepts.h> |
22 | #include <__type_traits/enable_if.h> |
23 | #include <__type_traits/invoke.h> |
24 | #include <__type_traits/is_callable.h> |
25 | #include <__utility/convert_to_integral.h> |
26 | #include <__utility/pair.h> |
27 | |
28 | #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
29 | # pragma GCC system_header |
30 | #endif |
31 | |
32 | _LIBCPP_BEGIN_NAMESPACE_STD |
33 | |
34 | template <class _AlgPolicy, class _Pred, class _Iter, class _Sent, class _SizeT, class _Type, class _Proj> |
35 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_Iter, _Iter> __search_n_forward_impl( |
36 | _Iter __first, _Sent __last, _SizeT __count, const _Type& __value, _Pred& __pred, _Proj& __proj) { |
37 | if (__count <= 0) |
38 | return std::make_pair(__first, __first); |
39 | while (true) { |
40 | // Find first element in sequence that matchs __value, with a mininum of loop checks |
41 | while (true) { |
42 | if (__first == __last) { // return __last if no element matches __value |
43 | _IterOps<_AlgPolicy>::__advance_to(__first, __last); |
44 | return std::make_pair(__first, __first); |
45 | } |
46 | if (std::__invoke(__pred, std::__invoke(__proj, *__first), __value)) |
47 | break; |
48 | ++__first; |
49 | } |
50 | // *__first matches __value, now match elements after here |
51 | _Iter __m = __first; |
52 | _SizeT __c(0); |
53 | while (true) { |
54 | if (++__c == __count) // If pattern exhausted, __first is the answer (works for 1 element pattern) |
55 | return std::make_pair(__first, ++__m); |
56 | if (++__m == __last) { // Otherwise if source exhaused, pattern not found |
57 | _IterOps<_AlgPolicy>::__advance_to(__first, __last); |
58 | return std::make_pair(__first, __first); |
59 | } |
60 | |
61 | // if there is a mismatch, restart with a new __first |
62 | if (!std::__invoke(__pred, std::__invoke(__proj, *__m), __value)) { |
63 | __first = __m; |
64 | ++__first; |
65 | break; |
66 | } // else there is a match, check next elements |
67 | } |
68 | } |
69 | } |
70 | |
71 | template <class _AlgPolicy, class _Pred, class _Iter, class _Sent, class _SizeT, class _Type, class _Proj, class _DiffT> |
72 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 std::pair<_Iter, _Iter> __search_n_random_access_impl( |
73 | _Iter __first, _Sent __last, _SizeT __count, const _Type& __value, _Pred& __pred, _Proj& __proj, _DiffT __size1) { |
74 | using difference_type = typename iterator_traits<_Iter>::difference_type; |
75 | if (__count == 0) |
76 | return std::make_pair(__first, __first); |
77 | if (__size1 < static_cast<_DiffT>(__count)) { |
78 | _IterOps<_AlgPolicy>::__advance_to(__first, __last); |
79 | return std::make_pair(__first, __first); |
80 | } |
81 | |
82 | const auto __s = __first + __size1 - difference_type(__count - 1); // Start of pattern match can't go beyond here |
83 | while (true) { |
84 | // Find first element in sequence that matchs __value, with a mininum of loop checks |
85 | while (true) { |
86 | if (__first >= __s) { // return __last if no element matches __value |
87 | _IterOps<_AlgPolicy>::__advance_to(__first, __last); |
88 | return std::make_pair(__first, __first); |
89 | } |
90 | if (std::__invoke(__pred, std::__invoke(__proj, *__first), __value)) |
91 | break; |
92 | ++__first; |
93 | } |
94 | // *__first matches __value_, now match elements after here |
95 | auto __m = __first; |
96 | _SizeT __c(0); |
97 | while (true) { |
98 | if (++__c == __count) // If pattern exhausted, __first is the answer (works for 1 element pattern) |
99 | return std::make_pair(__first, __first + _DiffT(__count)); |
100 | ++__m; // no need to check range on __m because __s guarantees we have enough source |
101 | |
102 | // if there is a mismatch, restart with a new __first |
103 | if (!std::__invoke(__pred, std::__invoke(__proj, *__m), __value)) { |
104 | __first = __m; |
105 | ++__first; |
106 | break; |
107 | } // else there is a match, check next elements |
108 | } |
109 | } |
110 | } |
111 | |
112 | template <class _Iter, |
113 | class _Sent, |
114 | class _DiffT, |
115 | class _Type, |
116 | class _Pred, |
117 | class _Proj, |
118 | __enable_if_t<__has_random_access_iterator_category<_Iter>::value, int> = 0> |
119 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_Iter, _Iter> |
120 | __search_n_impl(_Iter __first, _Sent __last, _DiffT __count, const _Type& __value, _Pred& __pred, _Proj& __proj) { |
121 | return std::__search_n_random_access_impl<_ClassicAlgPolicy>( |
122 | __first, __last, __count, __value, __pred, __proj, __last - __first); |
123 | } |
124 | |
125 | template <class _Iter1, |
126 | class _Sent1, |
127 | class _DiffT, |
128 | class _Type, |
129 | class _Pred, |
130 | class _Proj, |
131 | __enable_if_t<__has_forward_iterator_category<_Iter1>::value && |
132 | !__has_random_access_iterator_category<_Iter1>::value, |
133 | int> = 0> |
134 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_Iter1, _Iter1> |
135 | __search_n_impl(_Iter1 __first, _Sent1 __last, _DiffT __count, const _Type& __value, _Pred& __pred, _Proj& __proj) { |
136 | return std::__search_n_forward_impl<_ClassicAlgPolicy>(__first, __last, __count, __value, __pred, __proj); |
137 | } |
138 | |
139 | template <class _ForwardIterator, class _Size, class _Tp, class _BinaryPredicate> |
140 | [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator search_n( |
141 | _ForwardIterator __first, _ForwardIterator __last, _Size __count, const _Tp& __value, _BinaryPredicate __pred) { |
142 | static_assert( |
143 | __is_callable<_BinaryPredicate&, decltype(*__first), const _Tp&>::value, "The comparator has to be callable" ); |
144 | auto __proj = __identity(); |
145 | return std::__search_n_impl(__first, __last, std::__convert_to_integral(__count), __value, __pred, __proj).first; |
146 | } |
147 | |
148 | template <class _ForwardIterator, class _Size, class _Tp> |
149 | [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator |
150 | search_n(_ForwardIterator __first, _ForwardIterator __last, _Size __count, const _Tp& __value) { |
151 | return std::search_n(__first, __last, std::__convert_to_integral(__count), __value, __equal_to()); |
152 | } |
153 | |
154 | _LIBCPP_END_NAMESPACE_STD |
155 | |
156 | #endif // _LIBCPP___ALGORITHM_SEARCH_N_H |
157 | |