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 // <algorithm>
10
11 // UNSUPPORTED: c++03, c++11, c++14, c++17
12
13 // template<input_iterator I, sentinel_for<I> S, class Proj = identity,
14 // indirect_unary_predicate<projected<I, Proj>> Pred>
15 // constexpr I ranges::find_if(I first, S last, Pred pred, Proj proj = {});
16 // template<input_range R, class Proj = identity,
17 // indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
18 // constexpr borrowed_iterator_t<R>
19 // ranges::find_if(R&& r, Pred pred, Proj proj = {});
20
21 #include <algorithm>
22 #include <array>
23 #include <cassert>
24 #include <ranges>
25
26 #include "almost_satisfies_types.h"
27 #include "test_iterators.h"
28
29 struct Predicate {
30 bool operator()(int);
31 };
32
33 template <class It, class Sent = It>
34 concept HasFindIfIt = requires(It it, Sent sent) { std::ranges::find_if(it, sent, Predicate{}); };
35 static_assert(HasFindIfIt<int*>);
36 static_assert(!HasFindIfIt<InputIteratorNotDerivedFrom>);
37 static_assert(!HasFindIfIt<InputIteratorNotIndirectlyReadable>);
38 static_assert(!HasFindIfIt<InputIteratorNotInputOrOutputIterator>);
39 static_assert(!HasFindIfIt<cpp20_input_iterator<int*>, SentinelForNotSemiregular>);
40 static_assert(!HasFindIfIt<cpp20_input_iterator<int*>, InputRangeNotSentinelEqualityComparableWith>);
41
42 static_assert(!HasFindIfIt<int*, int>);
43 static_assert(!HasFindIfIt<int, int*>);
44
45 template <class Pred>
46 concept HasFindIfPred = requires(int* it, Pred pred) {std::ranges::find_if(it, it, pred); };
47
48 static_assert(!HasFindIfPred<IndirectUnaryPredicateNotCopyConstructible>);
49 static_assert(!HasFindIfPred<IndirectUnaryPredicateNotPredicate>);
50
51 template <class R>
52 concept HasFindIfR = requires(R r) { std::ranges::find_if(r, Predicate{}); };
53 static_assert(HasFindIfR<std::array<int, 0>>);
54 static_assert(!HasFindIfR<int>);
55 static_assert(!HasFindIfR<InputRangeNotDerivedFrom>);
56 static_assert(!HasFindIfR<InputRangeNotIndirectlyReadable>);
57 static_assert(!HasFindIfR<InputRangeNotInputOrOutputIterator>);
58 static_assert(!HasFindIfR<InputRangeNotSentinelSemiregular>);
59 static_assert(!HasFindIfR<InputRangeNotSentinelEqualityComparableWith>);
60
61 template <class It, class Sent = It>
test_iterators()62 constexpr void test_iterators() {
63 {
64 int a[] = {1, 2, 3, 4};
65 std::same_as<It> auto ret = std::ranges::find_if(It(a), Sent(It(a + 4)), [](int x) mutable { return x == 4; });
66 assert(base(ret) == a + 3);
67 assert(*ret == 4);
68 }
69 {
70 int a[] = {1, 2, 3, 4};
71 auto range = std::ranges::subrange(It(a), Sent(It(a + 4)));
72 std::same_as<It> auto ret = std::ranges::find_if(range, [](int x) mutable { return x == 4; });
73 assert(base(ret) == a + 3);
74 assert(*ret == 4);
75 }
76 }
77
78 struct NonConstComparable {
operator ==(const NonConstComparable &,const NonConstComparable &)79 friend constexpr bool operator==(const NonConstComparable&, const NonConstComparable&) { return false; }
operator ==(NonConstComparable &,NonConstComparable &)80 friend constexpr bool operator==(NonConstComparable&, NonConstComparable&) { return false; }
operator ==(const NonConstComparable &,NonConstComparable &)81 friend constexpr bool operator==(const NonConstComparable&, NonConstComparable&) { return false; }
operator ==(NonConstComparable &,const NonConstComparable &)82 friend constexpr bool operator==(NonConstComparable&, const NonConstComparable&) { return true; }
83 };
84
test()85 constexpr bool test() {
86 test_iterators<int*>();
87 test_iterators<const int*>();
88 test_iterators<cpp20_input_iterator<int*>, sentinel_wrapper<cpp20_input_iterator<int*>>>();
89 test_iterators<bidirectional_iterator<int*>>();
90 test_iterators<forward_iterator<int*>>();
91 test_iterators<random_access_iterator<int*>>();
92 test_iterators<contiguous_iterator<int*>>();
93
94 {
95 // check that projections are used properly and that they are called with the iterator directly
96 {
97 int a[] = {1, 2, 3, 4};
98 auto ret = std::ranges::find_if(a, a + 4, [&](int* i) { return i == a + 3; }, [](int& i) { return &i; });
99 assert(ret == a + 3);
100 }
101 {
102 int a[] = {1, 2, 3, 4};
103 auto ret = std::ranges::find_if(a, [&](int* i) { return i == a + 3; }, [](int& i) { return &i; });
104 assert(ret == a + 3);
105 }
106 }
107
108 {
109 // check that the first element is returned
110 {
111 struct S {
112 int comp;
113 int other;
114 };
115 S a[] = { {0, 0}, {0, 2}, {0, 1} };
116 auto ret = std::ranges::find_if(a, [](int i){ return i == 0; }, &S::comp);
117 assert(ret == a);
118 assert(ret->comp == 0);
119 assert(ret->other == 0);
120 }
121 {
122 struct S {
123 int comp;
124 int other;
125 };
126 S a[] = { {0, 0}, {0, 2}, {0, 1} };
127 auto ret = std::ranges::find_if(a, a + 3, [](int i) { return i == 0; }, &S::comp);
128 assert(ret == a);
129 assert(ret->comp == 0);
130 assert(ret->other == 0);
131 }
132 }
133
134 {
135 // check that end + 1 iterator is returned with no match
136 {
137 int a[] = {1, 1, 1};
138 auto ret = std::ranges::find_if(a, a + 3, [](int) { return false; });
139 assert(ret == a + 3);
140 }
141 {
142 int a[] = {1, 1, 1};
143 auto ret = std::ranges::find_if(a, [](int){ return false; });
144 assert(ret == a + 3);
145 }
146 }
147
148 {
149 // check that ranges::dangling is returned
150 [[maybe_unused]] std::same_as<std::ranges::dangling> auto ret =
151 std::ranges::find_if(std::array{1, 2}, [](int){ return false; });
152 }
153
154 {
155 // check that an iterator is returned with a borrowing range
156 int a[] = {1, 2, 3, 4};
157 std::same_as<int*> auto ret = std::ranges::find_if(std::views::all(a), [](int){ return true; });
158 assert(ret == a);
159 assert(*ret == 1);
160 }
161
162 {
163 // check that std::invoke is used
164 struct S { int i; };
165 S a[] = { S{1}, S{3}, S{2} };
166 std::same_as<S*> auto ret = std::ranges::find_if(a, [](int) { return false; }, &S::i);
167 assert(ret == a + 3);
168 }
169
170 {
171 // count projection and predicate invocation count
172 {
173 int a[] = {1, 2, 3, 4};
174 int predicate_count = 0;
175 int projection_count = 0;
176 auto ret = std::ranges::find_if(a, a + 4,
177 [&](int i) { ++predicate_count; return i == 2; },
178 [&](int i) { ++projection_count; return i; });
179 assert(ret == a + 1);
180 assert(*ret == 2);
181 assert(predicate_count == 2);
182 assert(projection_count == 2);
183 }
184 {
185 int a[] = {1, 2, 3, 4};
186 int predicate_count = 0;
187 int projection_count = 0;
188 auto ret = std::ranges::find_if(a,
189 [&](int i) { ++predicate_count; return i == 2; },
190 [&](int i) { ++projection_count; return i; });
191 assert(ret == a + 1);
192 assert(*ret == 2);
193 assert(predicate_count == 2);
194 assert(projection_count == 2);
195 }
196 }
197
198 {
199 // check that the return type of `iter::operator*` doesn't change
200 {
201 NonConstComparable a[] = { NonConstComparable{} };
202 auto ret = std::ranges::find_if(a, a + 1, [](auto&& e) { return e == NonConstComparable{}; });
203 assert(ret == a);
204 }
205 {
206 NonConstComparable a[] = { NonConstComparable{} };
207 auto ret = std::ranges::find_if(a, [](auto&& e) { return e == NonConstComparable{}; });
208 assert(ret == a);
209 }
210 }
211
212 {
213 // check that an empty range works
214 {
215 std::array<int ,0> a = {};
216 auto ret = std::ranges::find_if(a.begin(), a.end(), [](int) { return true; });
217 assert(ret == a.begin());
218 }
219 {
220 std::array<int, 0> a = {};
221 auto ret = std::ranges::find_if(a, [](int) { return true; });
222 assert(ret == a.begin());
223 }
224 }
225
226 return true;
227 }
228
main(int,char **)229 int main(int, char**) {
230 test();
231 static_assert(test());
232
233 return 0;
234 }
235