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_H
11 #define _LIBCPP___ALGORITHM_SEARCH_H
12
13 #include <__algorithm/comp.h>
14 #include <__algorithm/iterator_operations.h>
15 #include <__config>
16 #include <__functional/identity.h>
17 #include <__functional/invoke.h>
18 #include <__iterator/advance.h>
19 #include <__iterator/concepts.h>
20 #include <__iterator/iterator_traits.h>
21 #include <__type_traits/enable_if.h>
22 #include <__type_traits/is_callable.h>
23 #include <__utility/pair.h>
24
25 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
26 # pragma GCC system_header
27 #endif
28
29 _LIBCPP_BEGIN_NAMESPACE_STD
30
31 template <class _AlgPolicy,
32 class _Iter1, class _Sent1,
33 class _Iter2, class _Sent2,
34 class _Pred,
35 class _Proj1,
36 class _Proj2>
37 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
__search_forward_impl(_Iter1 __first1,_Sent1 __last1,_Iter2 __first2,_Sent2 __last2,_Pred & __pred,_Proj1 & __proj1,_Proj2 & __proj2)38 pair<_Iter1, _Iter1> __search_forward_impl(_Iter1 __first1, _Sent1 __last1,
39 _Iter2 __first2, _Sent2 __last2,
40 _Pred& __pred,
41 _Proj1& __proj1,
42 _Proj2& __proj2) {
43 if (__first2 == __last2)
44 return std::make_pair(__first1, __first1); // Everything matches an empty sequence
45 while (true) {
46 // Find first element in sequence 1 that matchs *__first2, with a mininum of loop checks
47 while (true) {
48 if (__first1 == __last1) { // return __last1 if no element matches *__first2
49 _IterOps<_AlgPolicy>::__advance_to(__first1, __last1);
50 return std::make_pair(__first1, __first1);
51 }
52 if (std::__invoke(__pred, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))
53 break;
54 ++__first1;
55 }
56 // *__first1 matches *__first2, now match elements after here
57 _Iter1 __m1 = __first1;
58 _Iter2 __m2 = __first2;
59 while (true) {
60 if (++__m2 == __last2) // If pattern exhausted, __first1 is the answer (works for 1 element pattern)
61 return std::make_pair(__first1, ++__m1);
62 if (++__m1 == __last1) { // Otherwise if source exhaused, pattern not found
63 return std::make_pair(__m1, __m1);
64 }
65
66 // if there is a mismatch, restart with a new __first1
67 if (!std::__invoke(__pred, std::__invoke(__proj1, *__m1), std::__invoke(__proj2, *__m2)))
68 {
69 ++__first1;
70 break;
71 } // else there is a match, check next elements
72 }
73 }
74 }
75
76 template <class _AlgPolicy,
77 class _Iter1, class _Sent1,
78 class _Iter2, class _Sent2,
79 class _Pred,
80 class _Proj1,
81 class _Proj2,
82 class _DiffT1,
83 class _DiffT2>
84 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
__search_random_access_impl(_Iter1 __first1,_Sent1 __last1,_Iter2 __first2,_Sent2 __last2,_Pred & __pred,_Proj1 & __proj1,_Proj2 & __proj2,_DiffT1 __size1,_DiffT2 __size2)85 pair<_Iter1, _Iter1> __search_random_access_impl(_Iter1 __first1, _Sent1 __last1,
86 _Iter2 __first2, _Sent2 __last2,
87 _Pred& __pred,
88 _Proj1& __proj1,
89 _Proj2& __proj2,
90 _DiffT1 __size1,
91 _DiffT2 __size2) {
92 const _Iter1 __s = __first1 + __size1 - _DiffT1(__size2 - 1); // Start of pattern match can't go beyond here
93
94 while (true) {
95 while (true) {
96 if (__first1 == __s) {
97 _IterOps<_AlgPolicy>::__advance_to(__first1, __last1);
98 return std::make_pair(__first1, __first1);
99 }
100 if (std::__invoke(__pred, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))
101 break;
102 ++__first1;
103 }
104
105 _Iter1 __m1 = __first1;
106 _Iter2 __m2 = __first2;
107 while (true) {
108 if (++__m2 == __last2)
109 return std::make_pair(__first1, __first1 + _DiffT1(__size2));
110 ++__m1; // no need to check range on __m1 because __s guarantees we have enough source
111 if (!std::__invoke(__pred, std::__invoke(__proj1, *__m1), std::__invoke(__proj2, *__m2))) {
112 ++__first1;
113 break;
114 }
115 }
116 }
117 }
118
119 template <class _Iter1, class _Sent1,
120 class _Iter2, class _Sent2,
121 class _Pred,
122 class _Proj1,
123 class _Proj2>
124 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
125 pair<_Iter1, _Iter1> __search_impl(_Iter1 __first1, _Sent1 __last1,
126 _Iter2 __first2, _Sent2 __last2,
127 _Pred& __pred,
128 _Proj1& __proj1,
129 _Proj2& __proj2,
130 __enable_if_t<__is_cpp17_random_access_iterator<_Iter1>::value
131 && __is_cpp17_random_access_iterator<_Iter2>::value>* = nullptr) {
132
133 auto __size2 = __last2 - __first2;
134 if (__size2 == 0)
135 return std::make_pair(__first1, __first1);
136
137 auto __size1 = __last1 - __first1;
138 if (__size1 < __size2) {
139 return std::make_pair(__last1, __last1);
140 }
141
142 return std::__search_random_access_impl<_ClassicAlgPolicy>(__first1, __last1,
143 __first2, __last2,
144 __pred,
145 __proj1,
146 __proj2,
147 __size1,
148 __size2);
149 }
150
151 template <class _Iter1, class _Sent1,
152 class _Iter2, class _Sent2,
153 class _Pred,
154 class _Proj1,
155 class _Proj2>
156 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
157 pair<_Iter1, _Iter1> __search_impl(_Iter1 __first1, _Sent1 __last1,
158 _Iter2 __first2, _Sent2 __last2,
159 _Pred& __pred,
160 _Proj1& __proj1,
161 _Proj2& __proj2,
162 __enable_if_t<__is_cpp17_forward_iterator<_Iter1>::value
163 && __is_cpp17_forward_iterator<_Iter2>::value
164 && !(__is_cpp17_random_access_iterator<_Iter1>::value
165 && __is_cpp17_random_access_iterator<_Iter2>::value)>* = nullptr) {
166 return std::__search_forward_impl<_ClassicAlgPolicy>(__first1, __last1,
167 __first2, __last2,
168 __pred,
169 __proj1,
170 __proj2);
171 }
172
173 template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
174 _LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
search(_ForwardIterator1 __first1,_ForwardIterator1 __last1,_ForwardIterator2 __first2,_ForwardIterator2 __last2,_BinaryPredicate __pred)175 _ForwardIterator1 search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
176 _ForwardIterator2 __first2, _ForwardIterator2 __last2,
177 _BinaryPredicate __pred) {
178 static_assert(__is_callable<_BinaryPredicate, decltype(*__first1), decltype(*__first2)>::value,
179 "BinaryPredicate has to be callable");
180 auto __proj = __identity();
181 return std::__search_impl(__first1, __last1, __first2, __last2, __pred, __proj, __proj).first;
182 }
183
184 template <class _ForwardIterator1, class _ForwardIterator2>
185 _LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
search(_ForwardIterator1 __first1,_ForwardIterator1 __last1,_ForwardIterator2 __first2,_ForwardIterator2 __last2)186 _ForwardIterator1 search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
187 _ForwardIterator2 __first2, _ForwardIterator2 __last2) {
188 return std::search(__first1, __last1, __first2, __last2, __equal_to());
189 }
190
191 #if _LIBCPP_STD_VER >= 17
192 template <class _ForwardIterator, class _Searcher>
193 _LIBCPP_NODISCARD_EXT _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
search(_ForwardIterator __f,_ForwardIterator __l,const _Searcher & __s)194 search(_ForwardIterator __f, _ForwardIterator __l, const _Searcher& __s) {
195 return __s(__f, __l).first;
196 }
197
198 #endif
199
200 _LIBCPP_END_NAMESPACE_STD
201
202 #endif // _LIBCPP___ALGORITHM_SEARCH_H
203