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