libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/ranges.copy_if.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, weakly_incrementable O, class Proj = identity,
  14 //          indirect_unary_predicate<projected<I, Proj>> Pred>
  15 //   requires indirectly_copyable<I, O>
  16 //   constexpr ranges::copy_if_result<I, O>
  17 //     ranges::copy_if(I first, S last, O result, Pred pred, Proj proj = {});
  18 // template<input_range R, weakly_incrementable O, class Proj = identity,
  19 //          indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
  20 //   requires indirectly_copyable<iterator_t<R>, O>
  21 //   constexpr ranges::copy_if_result<borrowed_iterator_t<R>, O>
  22 //     ranges::copy_if(R&& r, O result, Pred pred, Proj proj = {});
  23
  24 #include <algorithm>
  25 #include <array>
  26 #include <cassert>
  27 #include <ranges>
  28
  29 #include "almost_satisfies_types.h"
  30 #include "test_iterators.h"
  31
  32 struct Functor {
  33   bool operator()(int);
  34 };
  35
  36 template <class In, class Out = In, class Sent = sentinel_wrapper<In>, class Func = Functor>
  37 concept HasCopyIfIt = requires(In first, Sent last, Out result) { std::ranges::copy_if(first, last, result, Func{}); };
  38
  39 static_assert(HasCopyIfIt<int*>);
  40 static_assert(!HasCopyIfIt<InputIteratorNotDerivedFrom>);
  41 static_assert(!HasCopyIfIt<InputIteratorNotIndirectlyReadable>);
  42 static_assert(!HasCopyIfIt<InputIteratorNotInputOrOutputIterator>);
  43 static_assert(!HasCopyIfIt<int*, WeaklyIncrementableNotMovable>);
  44 struct NotIndirectlyCopyable {};
  45 static_assert(!HasCopyIfIt<int*, NotIndirectlyCopyable*>);
  46 static_assert(!HasCopyIfIt<int*, int*, SentinelForNotSemiregular>);
  47 static_assert(!HasCopyIfIt<int*, int*, SentinelForNotWeaklyEqualityComparableWith>);
  48
  49 static_assert(!HasCopyIfIt<int*, int*, int*, IndirectUnaryPredicateNotCopyConstructible>);
  50 static_assert(!HasCopyIfIt<int*, int*, int*, IndirectUnaryPredicateNotPredicate>);
  51
  52 template <class Range, class Out, class Func = Functor>
  53 concept HasCopyIfR = requires(Range range, Out out) { std::ranges::copy_if(range, out, Func{}); };
  54
  55 static_assert(HasCopyIfR<std::array<int, 10>, int*>);
  56 static_assert(!HasCopyIfR<InputRangeNotDerivedFrom, int*>);
  57 static_assert(!HasCopyIfR<InputRangeNotIndirectlyReadable, int*>);
  58 static_assert(!HasCopyIfR<InputRangeNotInputOrOutputIterator, int*>);
  59 static_assert(!HasCopyIfR<WeaklyIncrementableNotMovable, int*>);
  60 static_assert(!HasCopyIfR<UncheckedRange<NotIndirectlyCopyable*>, int*>);
  61 static_assert(!HasCopyIfR<InputRangeNotSentinelSemiregular, int*>);
  62 static_assert(!HasCopyIfR<InputRangeNotSentinelEqualityComparableWith, int*>);
  63
  64 static_assert(std::is_same_v<std::ranges::copy_if_result<int, long>, std::ranges::in_out_result<int, long>>);
  65
  66 template <class In, class Out, class Sent = In>
  67 constexpr void test_iterators() {
  68   { // simple test
  69     {
  70       std::array in = {1, 2, 3, 4};
  71       std::array<int, 4> out;
  72       std::same_as<std::ranges::copy_if_result<In, Out>> auto ret =
  73           std::ranges::copy_if(In(in.data()),
  74                                Sent(In(in.data() + in.size())),
  75                                Out(out.data()),
  76                                [](int) { return true; });
  77       assert(in == out);
  78       assert(base(ret.in) == in.data() + in.size());
  79       assert(base(ret.out) == out.data() + out.size());
  80     }
  81     {
  82       std::array in = {1, 2, 3, 4};
  83       std::array<int, 4> out;
  84       auto range = std::ranges::subrange(In(in.data()), Sent(In(in.data() + in.size())));
  85       std::same_as<std::ranges::copy_if_result<In, Out>> auto ret =
  86           std::ranges::copy_if(range, Out(out.data()), [](int) { return true; });
  87       assert(in == out);
  88       assert(base(ret.in) == in.data() + in.size());
  89       assert(base(ret.out) == out.data() + out.size());
  90     }
  91   }
  92
  93   { // check that an empty range works
  94     {
  95       std::array<int, 0> in;
  96       std::array<int, 0> out;
  97       auto ret = std::ranges::copy_if(In(in.data()), Sent(In(in.data())), Out(out.data()), [](int) { return true; });
  98       assert(base(ret.in) == in.data());
  99       assert(base(ret.out) == out.data());
 100     }
 101     {
 102       std::array<int, 0> in;
 103       std::array<int, 0> out;
 104       auto range = std::ranges::subrange(In(in.data()), Sent(In(in.data())));
 105       auto ret = std::ranges::copy_if(range, Out(out.data()), [](int) { return true; });
 106       assert(base(ret.in) == in.data());
 107       assert(base(ret.out) == out.data());
 108     }
 109   }
 110
 111   { // check that the predicate is used
 112     {
 113       std::array in = {4, 6, 87, 3, 88, 44, 45, 9};
 114       std::array<int, 4> out;
 115       auto ret = std::ranges::copy_if(In(in.data()),
 116                                       Sent(In(in.data() + in.size())),
 117                                       Out(out.data()),
 118                                       [](int i) { return i % 2 == 0; });
 119       assert((out == std::array{4, 6, 88, 44}));
 120       assert(base(ret.in) == in.data() + in.size());
 121       assert(base(ret.out) == out.data() + out.size());
 122     }
 123     {
 124       std::array in = {4, 6, 87, 3, 88, 44, 45, 9};
 125       std::array<int, 4> out;
 126       auto range = std::ranges::subrange(In(in.data()), Sent(In(in.data() + in.size())));
 127       auto ret = std::ranges::copy_if(range, Out(out.data()), [](int i) { return i % 2 == 0; });
 128       assert((out == std::array{4, 6, 88, 44}));
 129       assert(base(ret.in) == in.data() + in.size());
 130       assert(base(ret.out) == out.data() + out.size());
 131     }
 132   }
 133 }
 134
 135 template <class Out>
 136 constexpr bool test_in_iterators() {
 137   test_iterators<cpp17_input_iterator<int*>, Out, sentinel_wrapper<cpp17_input_iterator<int*>>>();
 138   test_iterators<cpp20_input_iterator<int*>, Out, sentinel_wrapper<cpp20_input_iterator<int*>>>();
 139   test_iterators<forward_iterator<int*>, Out>();
 140   test_iterators<bidirectional_iterator<int*>, Out>();
 141   test_iterators<random_access_iterator<int*>, Out>();
 142   test_iterators<contiguous_iterator<int*>, Out>();
 143   test_iterators<int*, Out>();
 144
 145   return true;
 146 }
 147
 148 constexpr bool test() {
 149   test_in_iterators<cpp17_output_iterator<int*>>();
 150   test_in_iterators<cpp20_output_iterator<int*>>();
 151   test_in_iterators<forward_iterator<int*>>();
 152   test_in_iterators<bidirectional_iterator<int*>>();
 153   test_in_iterators<random_access_iterator<int*>>();
 154   test_in_iterators<contiguous_iterator<int*>>();
 155   test_in_iterators<int*>();
 156
 157   { // check that std::invoke is used
 158     {
 159       struct S { int val; int other; };
 160       std::array<S, 4> in = {{{4, 2}, {1, 3}, {3, 4}, {3, 5}}};
 161       std::array<S, 2> out;
 162       auto ret = std::ranges::copy_if(in.begin(), in.end(), out.begin(), [](int i) { return i == 3; }, &S::val);
 163       assert(ret.in == in.end());
 164       assert(ret.out == out.end());
 165       assert(out[0].val == 3);
 166       assert(out[0].other == 4);
 167       assert(out[1].val == 3);
 168       assert(out[1].other == 5);
 169     }
 170     {
 171       struct S { int val; int other; };
 172       std::array<S, 4> in = {{{4, 2}, {1, 3}, {3, 4}, {3, 5}}};
 173       std::array<S, 2> out;
 174       auto ret = std::ranges::copy_if(in, out.begin(), [](int i) { return i == 3; }, &S::val);
 175       assert(ret.in == in.end());
 176       assert(ret.out == out.end());
 177       assert(out[0].val == 3);
 178       assert(out[0].other == 4);
 179       assert(out[1].val == 3);
 180       assert(out[1].other == 5);
 181     }
 182   }
 183
 184   { // check that the complexity requirements are met
 185     {
 186       int predicateCount = 0;
 187       int projectionCount = 0;
 188       auto pred = [&](int i) { ++predicateCount; return i != 0; };
 189       auto proj = [&](int i) { ++projectionCount; return i; };
 190
 191       int a[] = {5, 4, 3, 2, 1};
 192       int b[5];
 193       std::ranges::copy_if(a, a + 5, b, pred, proj);
 194       assert(predicateCount == 5);
 195       assert(projectionCount == 5);
 196     }
 197     {
 198       int predicateCount = 0;
 199       int projectionCount = 0;
 200       auto pred = [&](int i) { ++predicateCount; return i != 0; };
 201       auto proj = [&](int i) { ++projectionCount; return i; };
 202
 203       int a[] = {5, 4, 3, 2, 1};
 204       int b[5];
 205       std::ranges::copy_if(a, b, pred, proj);
 206       assert(predicateCount == 5);
 207       assert(projectionCount == 5);
 208     }
 209   }
 210
 211   { // test proxy iterator
 212     {
 213       std::array in = {4, 6, 87, 3, 88, 44, 45, 9};
 214       std::array<int, 4> out;
 215
 216       ProxyRange proxyIn{in};
 217       ProxyRange proxyOut{out};
 218
 219       std::ranges::copy_if(proxyIn.begin(), proxyIn.end(), proxyOut.begin(),
 220                           [](auto const& i) { return i.data % 2 == 0; });
 221       assert((out == std::array{4, 6, 88, 44}));
 222     }
 223     {
 224       std::array in = {4, 6, 87, 3, 88, 44, 45, 9};
 225       std::array<int, 4> out;
 226
 227       ProxyRange proxyIn{in};
 228       ProxyRange proxyOut{out};
 229
 230       std::ranges::copy_if(proxyIn, proxyOut.begin(), [](const auto& i) { return i.data % 2 == 0; });
 231       assert((out == std::array{4, 6, 88, 44}));
 232     }
 233   }
 234
 235   return true;
 236 }
 237
 238 int main(int, char**) {
 239   test();
 240   static_assert(test());
 241
 242   return 0;
 243 }