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 // UNSUPPORTED: libcpp-has-no-incomplete-ranges 13 14 // template<input_iterator I, sentinel_for<I> S, class Proj = identity, 15 // indirect_unary_predicate<projected<I, Proj>> Pred> 16 // constexpr I ranges::find_if(I first, S last, Pred pred, Proj proj = {}); 17 // template<input_range R, class Proj = identity, 18 // indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred> 19 // constexpr borrowed_iterator_t<R> 20 // ranges::find_if(R&& r, Pred pred, Proj proj = {}); 21 22 #include <algorithm> 23 #include <array> 24 #include <cassert> 25 #include <ranges> 26 27 #include "almost_satisfies_types.h" 28 #include "boolean_testable.h" 29 #include "test_iterators.h" 30 31 struct Predicate { 32 bool operator()(int); 33 }; 34 35 template <class It, class Sent = It> 36 concept HasFindIfIt = requires(It it, Sent sent) { std::ranges::find_if(it, sent, Predicate{}); }; 37 static_assert(HasFindIfIt<int*>); 38 static_assert(!HasFindIfIt<InputIteratorNotDerivedFrom>); 39 static_assert(!HasFindIfIt<InputIteratorNotIndirectlyReadable>); 40 static_assert(!HasFindIfIt<InputIteratorNotInputOrOutputIterator>); 41 static_assert(!HasFindIfIt<cpp20_input_iterator<int*>, SentinelForNotSemiregular>); 42 static_assert(!HasFindIfIt<cpp20_input_iterator<int*>, InputRangeNotSentinelEqualityComparableWith>); 43 44 static_assert(!HasFindIfIt<int*, int>); 45 static_assert(!HasFindIfIt<int, int*>); 46 47 template <class Pred> 48 concept HasFindIfPred = requires(int* it, Pred pred) {std::ranges::find_if(it, it, pred); }; 49 50 static_assert(!HasFindIfPred<IndirectUnaryPredicateNotCopyConstructible>); 51 static_assert(!HasFindIfPred<IndirectUnaryPredicateNotPredicate>); 52 53 template <class R> 54 concept HasFindIfR = requires(R r) { std::ranges::find_if(r, Predicate{}); }; 55 static_assert(HasFindIfR<std::array<int, 0>>); 56 static_assert(!HasFindIfR<int>); 57 static_assert(!HasFindIfR<InputRangeNotDerivedFrom>); 58 static_assert(!HasFindIfR<InputRangeNotIndirectlyReadable>); 59 static_assert(!HasFindIfR<InputRangeNotInputOrOutputIterator>); 60 static_assert(!HasFindIfR<InputRangeNotSentinelSemiregular>); 61 static_assert(!HasFindIfR<InputRangeNotSentinelEqualityComparableWith>); 62 63 template <class It, class Sent = It> 64 constexpr void test_iterators() { 65 { 66 int a[] = {1, 2, 3, 4}; 67 std::same_as<It> auto ret = std::ranges::find_if(It(a), Sent(It(a + 4)), [](int x) mutable { return x == 4; }); 68 assert(base(ret) == a + 3); 69 assert(*ret == 4); 70 } 71 { 72 int a[] = {1, 2, 3, 4}; 73 auto range = std::ranges::subrange(It(a), Sent(It(a + 4))); 74 std::same_as<It> auto ret = std::ranges::find_if(range, [](int x) mutable { return x == 4; }); 75 assert(base(ret) == a + 3); 76 assert(*ret == 4); 77 } 78 } 79 80 struct NonConstComparable { 81 friend constexpr bool operator==(const NonConstComparable&, const NonConstComparable&) { return false; } 82 friend constexpr bool operator==(NonConstComparable&, NonConstComparable&) { return false; } 83 friend constexpr bool operator==(const NonConstComparable&, NonConstComparable&) { return false; } 84 friend constexpr bool operator==(NonConstComparable&, const NonConstComparable&) { return true; } 85 }; 86 87 constexpr bool test() { 88 test_iterators<int*>(); 89 test_iterators<const int*>(); 90 test_iterators<cpp20_input_iterator<int*>, sentinel_wrapper<cpp20_input_iterator<int*>>>(); 91 test_iterators<bidirectional_iterator<int*>>(); 92 test_iterators<forward_iterator<int*>>(); 93 test_iterators<random_access_iterator<int*>>(); 94 test_iterators<contiguous_iterator<int*>>(); 95 96 { 97 // check that projections are used properly and that they are called with the iterator directly 98 { 99 int a[] = {1, 2, 3, 4}; 100 auto ret = std::ranges::find_if(a, a + 4, [&](int* i) { return i == a + 3; }, [](int& i) { return &i; }); 101 assert(ret == a + 3); 102 } 103 { 104 int a[] = {1, 2, 3, 4}; 105 auto ret = std::ranges::find_if(a, [&](int* i) { return i == a + 3; }, [](int& i) { return &i; }); 106 assert(ret == a + 3); 107 } 108 } 109 110 { 111 // check that the first element is returned 112 { 113 struct S { 114 int comp; 115 int other; 116 }; 117 S a[] = { {0, 0}, {0, 2}, {0, 1} }; 118 auto ret = std::ranges::find_if(a, [](int i){ return i == 0; }, &S::comp); 119 assert(ret == a); 120 assert(ret->comp == 0); 121 assert(ret->other == 0); 122 } 123 { 124 struct S { 125 int comp; 126 int other; 127 }; 128 S a[] = { {0, 0}, {0, 2}, {0, 1} }; 129 auto ret = std::ranges::find_if(a, a + 3, [](int i) { return i == 0; }, &S::comp); 130 assert(ret == a); 131 assert(ret->comp == 0); 132 assert(ret->other == 0); 133 } 134 } 135 136 { 137 // check that end + 1 iterator is returned with no match 138 { 139 int a[] = {1, 1, 1}; 140 auto ret = std::ranges::find_if(a, a + 3, [](int) { return false; }); 141 assert(ret == a + 3); 142 } 143 { 144 int a[] = {1, 1, 1}; 145 auto ret = std::ranges::find_if(a, [](int){ return false; }); 146 assert(ret == a + 3); 147 } 148 } 149 150 { 151 // check that ranges::dangling is returned 152 [[maybe_unused]] std::same_as<std::ranges::dangling> auto ret = 153 std::ranges::find_if(std::array{1, 2}, [](int){ return false; }); 154 } 155 156 { 157 // check that an iterator is returned with a borrowing range 158 int a[] = {1, 2, 3, 4}; 159 std::same_as<int*> auto ret = std::ranges::find_if(std::views::all(a), [](int){ return true; }); 160 assert(ret == a); 161 assert(*ret == 1); 162 } 163 164 { 165 // check that std::invoke is used 166 struct S { int i; }; 167 S a[] = { S{1}, S{3}, S{2} }; 168 std::same_as<S*> auto ret = std::ranges::find_if(a, [](int) { return false; }, &S::i); 169 assert(ret == a + 3); 170 } 171 172 { 173 // count projection and predicate invocation count 174 { 175 int a[] = {1, 2, 3, 4}; 176 int predicate_count = 0; 177 int projection_count = 0; 178 auto ret = std::ranges::find_if(a, a + 4, 179 [&](int i) { ++predicate_count; return i == 2; }, 180 [&](int i) { ++projection_count; return i; }); 181 assert(ret == a + 1); 182 assert(*ret == 2); 183 assert(predicate_count == 2); 184 assert(projection_count == 2); 185 } 186 { 187 int a[] = {1, 2, 3, 4}; 188 int predicate_count = 0; 189 int projection_count = 0; 190 auto ret = std::ranges::find_if(a, 191 [&](int i) { ++predicate_count; return i == 2; }, 192 [&](int i) { ++projection_count; return i; }); 193 assert(ret == a + 1); 194 assert(*ret == 2); 195 assert(predicate_count == 2); 196 assert(projection_count == 2); 197 } 198 } 199 200 { 201 // check that the return type of `iter::operator*` doesn't change 202 { 203 NonConstComparable a[] = { NonConstComparable{} }; 204 auto ret = std::ranges::find_if(a, a + 1, [](auto&& e) { return e == NonConstComparable{}; }); 205 assert(ret == a); 206 } 207 { 208 NonConstComparable a[] = { NonConstComparable{} }; 209 auto ret = std::ranges::find_if(a, [](auto&& e) { return e == NonConstComparable{}; }); 210 assert(ret == a); 211 } 212 } 213 214 { 215 // check that an empty range works 216 { 217 std::array<int ,0> a = {}; 218 auto ret = std::ranges::find_if(a.begin(), a.end(), [](int) { return true; }); 219 assert(ret == a.begin()); 220 } 221 { 222 std::array<int, 0> a = {}; 223 auto ret = std::ranges::find_if(a, [](int) { return true; }); 224 assert(ret == a.begin()); 225 } 226 } 227 228 { 229 // check that the implicit conversion to bool works 230 { 231 int a[] = {1, 2, 3, 4}; 232 auto ret = std::ranges::find_if(a, a + 4, [](const int& i) { return BooleanTestable{i == 3}; }); 233 assert(ret == a + 2); 234 } 235 { 236 int a[] = {1, 2, 3, 4}; 237 auto ret = std::ranges::find_if(a, [](const int& b) { return BooleanTestable{b == 3}; }); 238 assert(ret == a + 2); 239 } 240 } 241 242 return true; 243 } 244 245 int main(int, char**) { 246 test(); 247 static_assert(test()); 248 249 return 0; 250 } 251