libcxx/test/std/algorithms/alg.nonmodifying/alg.find/ranges.find_if_not.pass.cpp

   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_not(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_not(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 "boolean_testable.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 HasFindIfNotIt = requires(It it, Sent sent) { std::ranges::find_if_not(it, sent, Predicate{}); };
  36 static_assert(HasFindIfNotIt<int*>);
  37 static_assert(!HasFindIfNotIt<InputIteratorNotDerivedFrom>);
  38 static_assert(!HasFindIfNotIt<InputIteratorNotIndirectlyReadable>);
  39 static_assert(!HasFindIfNotIt<InputIteratorNotInputOrOutputIterator>);
  40 static_assert(!HasFindIfNotIt<cpp20_input_iterator<int*>, SentinelForNotSemiregular>);
  41 static_assert(!HasFindIfNotIt<cpp20_input_iterator<int*>, InputRangeNotSentinelEqualityComparableWith>);
  42
  43 static_assert(!HasFindIfNotIt<int*, int>);
  44 static_assert(!HasFindIfNotIt<int, int*>);
  45
  46 template <class Pred>
  47 concept HasFindIfNotPred = requires(int* it, Pred pred) {std::ranges::find_if_not(it, it, pred); };
  48
  49 static_assert(!HasFindIfNotPred<IndirectUnaryPredicateNotCopyConstructible>);
  50 static_assert(!HasFindIfNotPred<IndirectUnaryPredicateNotPredicate>);
  51
  52 template <class R>
  53 concept HasFindIfNotR = requires(R r) { std::ranges::find_if_not(r, Predicate{}); };
  54 static_assert(HasFindIfNotR<std::array<int, 0>>);
  55 static_assert(!HasFindIfNotR<int>);
  56 static_assert(!HasFindIfNotR<InputRangeNotDerivedFrom>);
  57 static_assert(!HasFindIfNotR<InputRangeNotIndirectlyReadable>);
  58 static_assert(!HasFindIfNotR<InputRangeNotInputOrOutputIterator>);
  59 static_assert(!HasFindIfNotR<InputRangeNotSentinelSemiregular>);
  60 static_assert(!HasFindIfNotR<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_not(It(a), Sent(It(a + 4)), [c = 0](int) mutable { return c++ <= 2; });
  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_not(range, [c = 0](int) mutable { return c++ <= 2; });
  74     assert(base(ret) == a + 3);
  75     assert(*ret == 4);
  76   }
  77 }
  78
  79 struct NonConstComparableLValue {
  80   friend constexpr bool operator==(const NonConstComparableLValue&, const NonConstComparableLValue&) { return false; }
  81   friend constexpr bool operator==(NonConstComparableLValue&, NonConstComparableLValue&) { return false; }
  82   friend constexpr bool operator==(const NonConstComparableLValue&, NonConstComparableLValue&) { return false; }
  83   friend constexpr bool operator==(NonConstComparableLValue&, const NonConstComparableLValue&) { 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   { // 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_not(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_not(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_not(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_not(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   { // check that ranges::dangling is returned
 149     [[maybe_unused]] std::same_as<std::ranges::dangling> auto ret =
 150       std::ranges::find_if_not(std::array{1, 2}, [](int){ return true; });
 151   }
 152
 153   { // check that an iterator is returned with a borrowing range
 154     int a[] = {1, 2, 3, 4};
 155     std::same_as<int*> auto ret = std::ranges::find_if_not(std::views::all(a), [](int){ return false; });
 156     assert(ret == a);
 157     assert(*ret == 1);
 158   }
 159
 160   { // check that std::invoke is used
 161     struct S { int i; };
 162     S a[] = { S{1}, S{3}, S{2} };
 163     std::same_as<S*> auto ret = std::ranges::find_if_not(a, [](int) { return true; }, &S::i);
 164     assert(ret == a + 3);
 165   }
 166
 167   { // count projection and predicate invocation count
 168     {
 169       int a[] = {1, 2, 3, 4};
 170       int predicate_count = 0;
 171       int projection_count = 0;
 172       auto ret = std::ranges::find_if_not(a, a + 4,
 173                                       [&](int i) { ++predicate_count; return i != 2; },
 174                                       [&](int i) { ++projection_count; return i; });
 175       assert(ret == a + 1);
 176       assert(*ret == 2);
 177       assert(predicate_count == 2);
 178       assert(projection_count == 2);
 179     }
 180     {
 181       int a[] = {1, 2, 3, 4};
 182       int predicate_count = 0;
 183       int projection_count = 0;
 184       auto ret = std::ranges::find_if_not(a,
 185                                       [&](int i) { ++predicate_count; return i != 2; },
 186                                       [&](int i) { ++projection_count; return i; });
 187       assert(ret == a + 1);
 188       assert(*ret == 2);
 189       assert(predicate_count == 2);
 190       assert(projection_count == 2);
 191     }
 192   }
 193
 194   { // check that the return type of `iter::operator*` doesn't change
 195     {
 196       NonConstComparableLValue a[] = { NonConstComparableLValue{} };
 197       auto ret = std::ranges::find_if_not(a, a + 1, [](auto&& e) { return e != NonConstComparableLValue{}; });
 198       assert(ret == a);
 199     }
 200     {
 201       NonConstComparableLValue a[] = { NonConstComparableLValue{} };
 202       auto ret = std::ranges::find_if_not(a, [](auto&& e) { return e != NonConstComparableLValue{}; });
 203       assert(ret == a);
 204     }
 205   }
 206
 207   {
 208     // check that an empty range works
 209     {
 210       std::array<int ,0> a = {};
 211       auto ret = std::ranges::find_if_not(a.begin(), a.end(), [](int) { return true; });
 212       assert(ret == a.begin());
 213     }
 214     {
 215       std::array<int, 0> a = {};
 216       auto ret = std::ranges::find_if_not(a, [](int) { return true; });
 217       assert(ret == a.begin());
 218     }
 219   }
 220
 221   {
 222     // check that the implicit conversion to bool works
 223     {
 224       int a[] = {1, 2, 3, 4};
 225       auto ret = std::ranges::find_if_not(a, a + 4, [](const int& i) { return BooleanTestable{i != 3}; });
 226       assert(ret == a + 2);
 227     }
 228     {
 229       int a[] = {1, 2, 3, 4};
 230       auto ret = std::ranges::find_if_not(a, [](const int& b) { return BooleanTestable{b != 3}; });
 231       assert(ret == a + 2);
 232     }
 233   }
 234
 235   return true;
 236 }
 237
 238 int main(int, char**) {
 239   test();
 240   static_assert(test());
 241
 242   return 0;
 243 }