1 // -*- C++ -*-
2
3 // Copyright (C) 2007-2023 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the terms
7 // of the GNU General Public License as published by the Free Software
8 // Foundation; either version 3, or (at your option) any later
9 // version.
10
11 // This library is distributed in the hope that it will be useful, but
12 // WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 // General Public License for more details.
15
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
24
25 /** @file parallel/find_selectors.h
26 * @brief _Function objects representing different tasks to be plugged
27 * into the parallel find algorithm.
28 * This file is a GNU parallel extension to the Standard C++ Library.
29 */
30
31 // Written by Felix Putze.
32
33 #ifndef _GLIBCXX_PARALLEL_FIND_SELECTORS_H
34 #define _GLIBCXX_PARALLEL_FIND_SELECTORS_H 1
35
36 #include <parallel/tags.h>
37 #include <parallel/basic_iterator.h>
38 #include <bits/stl_pair.h>
39
40 namespace __gnu_parallel
41 {
42 /** @brief Base class of all __gnu_parallel::__find_template selectors. */
43 struct __generic_find_selector
44 { };
45
46 /**
47 * @brief Test predicate on a single element, used for std::find()
48 * and std::find_if ().
49 */
50 struct __find_if_selector : public __generic_find_selector
51 {
52 /** @brief Test on one position.
53 * @param __i1 _Iterator on first sequence.
54 * @param __i2 _Iterator on second sequence (unused).
55 * @param __pred Find predicate.
56 */
57 template<typename _RAIter1, typename _RAIter2,
58 typename _Pred>
59 bool
60 operator()(_RAIter1 __i1, _RAIter2 __i2, _Pred __pred)
61 { return __pred(*__i1); }
62
63 /** @brief Corresponding sequential algorithm on a sequence.
64 * @param __begin1 Begin iterator of first sequence.
65 * @param __end1 End iterator of first sequence.
66 * @param __begin2 Begin iterator of second sequence.
67 * @param __pred Find predicate.
68 */
69 template<typename _RAIter1, typename _RAIter2,
70 typename _Pred>
71 std::pair<_RAIter1, _RAIter2>
72 _M_sequential_algorithm(_RAIter1 __begin1,
73 _RAIter1 __end1,
74 _RAIter2 __begin2, _Pred __pred)
75 { return std::make_pair(find_if(__begin1, __end1, __pred,
76 sequential_tag()), __begin2); }
77 };
78
79 /** @brief Test predicate on two adjacent elements. */
80 struct __adjacent_find_selector : public __generic_find_selector
81 {
82 /** @brief Test on one position.
83 * @param __i1 _Iterator on first sequence.
84 * @param __i2 _Iterator on second sequence (unused).
85 * @param __pred Find predicate.
86 */
87 template<typename _RAIter1, typename _RAIter2,
88 typename _Pred>
89 bool
90 operator()(_RAIter1 __i1, _RAIter2 __i2, _Pred __pred)
91 {
92 // Passed end iterator is one short.
93 return __pred(*__i1, *(__i1 + 1));
94 }
95
96 /** @brief Corresponding sequential algorithm on a sequence.
97 * @param __begin1 Begin iterator of first sequence.
98 * @param __end1 End iterator of first sequence.
99 * @param __begin2 Begin iterator of second sequence.
100 * @param __pred Find predicate.
101 */
102 template<typename _RAIter1, typename _RAIter2,
103 typename _Pred>
104 std::pair<_RAIter1, _RAIter2>
105 _M_sequential_algorithm(_RAIter1 __begin1,
106 _RAIter1 __end1,
107 _RAIter2 __begin2, _Pred __pred)
108 {
109 // Passed end iterator is one short.
110 _RAIter1 __spot = adjacent_find(__begin1, __end1 + 1,
111 __pred, sequential_tag());
112 if (__spot == (__end1 + 1))
113 __spot = __end1;
114 return std::make_pair(__spot, __begin2);
115 }
116 };
117
118 /** @brief Test inverted predicate on a single element. */
119 struct __mismatch_selector : public __generic_find_selector
120 {
121 /**
122 * @brief Test on one position.
123 * @param __i1 _Iterator on first sequence.
124 * @param __i2 _Iterator on second sequence (unused).
125 * @param __pred Find predicate.
126 */
127 template<typename _RAIter1, typename _RAIter2,
128 typename _Pred>
129 bool
130 operator()(_RAIter1 __i1, _RAIter2 __i2, _Pred __pred)
131 { return !__pred(*__i1, *__i2); }
132
133 /**
134 * @brief Corresponding sequential algorithm on a sequence.
135 * @param __begin1 Begin iterator of first sequence.
136 * @param __end1 End iterator of first sequence.
137 * @param __begin2 Begin iterator of second sequence.
138 * @param __pred Find predicate.
139 */
140 template<typename _RAIter1, typename _RAIter2,
141 typename _Pred>
142 std::pair<_RAIter1, _RAIter2>
143 _M_sequential_algorithm(_RAIter1 __begin1,
144 _RAIter1 __end1,
145 _RAIter2 __begin2, _Pred __pred)
146 { return mismatch(__begin1, __end1, __begin2,
147 __pred, sequential_tag()); }
148 };
149
150
151 /** @brief Test predicate on several elements. */
152 template<typename _FIterator>
153 struct __find_first_of_selector : public __generic_find_selector
154 {
155 _FIterator _M_begin;
156 _FIterator _M_end;
157
158 explicit __find_first_of_selector(_FIterator __begin,
159 _FIterator __end)
160 : _M_begin(__begin), _M_end(__end) { }
161
162 /** @brief Test on one position.
163 * @param __i1 _Iterator on first sequence.
164 * @param __i2 _Iterator on second sequence (unused).
165 * @param __pred Find predicate. */
166 template<typename _RAIter1, typename _RAIter2,
167 typename _Pred>
168 bool
169 operator()(_RAIter1 __i1, _RAIter2 __i2, _Pred __pred)
170 {
171 for (_FIterator __pos_in_candidates = _M_begin;
172 __pos_in_candidates != _M_end; ++__pos_in_candidates)
173 if (__pred(*__i1, *__pos_in_candidates))
174 return true;
175 return false;
176 }
177
178 /** @brief Corresponding sequential algorithm on a sequence.
179 * @param __begin1 Begin iterator of first sequence.
180 * @param __end1 End iterator of first sequence.
181 * @param __begin2 Begin iterator of second sequence.
182 * @param __pred Find predicate. */
183 template<typename _RAIter1, typename _RAIter2,
184 typename _Pred>
185 std::pair<_RAIter1, _RAIter2>
186 _M_sequential_algorithm(_RAIter1 __begin1,
187 _RAIter1 __end1,
188 _RAIter2 __begin2, _Pred __pred)
189 {
190 return std::make_pair(find_first_of(__begin1, __end1,
191 _M_begin, _M_end, __pred,
192 sequential_tag()), __begin2);
193 }
194 };
195 }
196
197 #endif /* _GLIBCXX_PARALLEL_FIND_SELECTORS_H */