libcxx/test/std/algorithms/alg.modifying.operations/alg.transform/ranges.transform.binary.range.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 // UNSUPPORTED: c++03, c++11, c++14, c++17
  10
  11 // <algorithm>
  12
  13 // template<input_range R1, input_range R2, weakly_incrementable O,
  14 //          copy_constructible F, class Proj1 = identity, class Proj2 = identity>
  15 //   requires indirectly_writable<O, indirect_result_t<F&, projected<iterator_t<R1>, Proj1>,
  16 //                                          projected<iterator_t<R2>, Proj2>>>
  17 //   constexpr ranges::binary_transform_result<borrowed_iterator_t<R1>, borrowed_iterator_t<R2>, O>
  18 //     ranges::transform(R1&& r1, R2&& r2, O result,
  19 //                       F binary_op, Proj1 proj1 = {}, Proj2 proj2 = {});
  20
  21 // The iterator overloads are tested in ranges.transform.binary.iterator.pass.cpp.
  22
  23 #include <algorithm>
  24 #include <array>
  25 #include <cassert>
  26 #include <functional>
  27 #include <ranges>
  28
  29 #include "test_iterators.h"
  30 #include "almost_satisfies_types.h"
  31
  32 struct BinaryFunc {
  33   int operator()(int, int);
  34 };
  35
  36 template <class Range>
  37 concept HasTransformR = requires(Range r, int* out) { std::ranges::transform(r, r, out, BinaryFunc{}); };
  38
  39 static_assert(HasTransformR<std::array<int, 1>>);
  40 static_assert(!HasTransformR<int>);
  41 static_assert(!HasTransformR<InputRangeNotDerivedFrom>);
  42 static_assert(!HasTransformR<InputRangeNotIndirectlyReadable>);
  43 static_assert(!HasTransformR<InputRangeNotInputOrOutputIterator>);
  44 static_assert(!HasTransformR<InputRangeNotSentinelSemiregular>);
  45 static_assert(!HasTransformR<InputRangeNotSentinelEqualityComparableWith>);
  46
  47 template <class It>
  48 concept HasTransformOut = requires(int* it, int* sent, It out, std::array<int, 2> range) {
  49   std::ranges::transform(range, range, out, BinaryFunc{});
  50 };
  51 static_assert(HasTransformOut<int*>);
  52 static_assert(!HasTransformOut<WeaklyIncrementableNotMovable>);
  53
  54 // check indirectly_readable
  55 static_assert(HasTransformOut<char*>);
  56 static_assert(!HasTransformOut<int**>);
  57
  58 struct MoveOnlyFunctor {
  59   MoveOnlyFunctor(const MoveOnlyFunctor&) = delete;
  60   MoveOnlyFunctor(MoveOnlyFunctor&&)      = default;
  61   int operator()(int, int);
  62 };
  63
  64 template <class Func>
  65 concept HasTransformFuncBinary = requires(int* it, int* sent, int* out, std::array<int, 2> range, Func func) {
  66   std::ranges::transform(range, range, out, func);
  67 };
  68 static_assert(HasTransformFuncBinary<BinaryFunc>);
  69 static_assert(!HasTransformFuncBinary<MoveOnlyFunctor>);
  70
  71 static_assert(std::is_same_v<std::ranges::binary_transform_result<int, long, char>,
  72                              std::ranges::in_in_out_result<int, long, char>>);
  73
  74 // clang-format off
  75 template <class In1, class In2, class Out, class Sent1, class Sent2>
  76 constexpr bool test_iterators() {
  77   { // simple
  78     int a[] = {1, 2, 3, 4, 5};
  79     int b[] = {5, 4, 3, 2, 1};
  80     int c[5];
  81
  82     auto range1 = std::ranges::subrange(In1(a), Sent1(In1(a + 5)));
  83     auto range2 = std::ranges::subrange(In2(b), Sent2(In2(b + 5)));
  84
  85     std::same_as<std::ranges::in_in_out_result<In1, In2, Out>> decltype(auto) ret = std::ranges::transform(
  86         range1, range2, Out(c), [](int i, int j) { return i + j; });
  87
  88     assert((std::to_array(c) == std::array{6, 6, 6, 6, 6}));
  89     assert(base(ret.in1) == a + 5);
  90     assert(base(ret.in2) == b + 5);
  91     assert(base(ret.out) == c + 5);
  92   }
  93
  94   { // first range empty
  95     std::array<int, 0> a = {};
  96     int b[] = {5, 4, 3, 2, 1};
  97     int c[5];
  98
  99     auto range1 = std::ranges::subrange(In1(a.data()), Sent1(In1(a.data())));
 100     auto range2 = std::ranges::subrange(In2(b), Sent2(In2(b + 5)));
 101
 102     auto ret = std::ranges::transform(range1, range2, Out(c), [](int i, int j) { return i + j; });
 103
 104     assert(base(ret.in1) == a.data());
 105     assert(base(ret.in2) == b);
 106     assert(base(ret.out) == c);
 107   }
 108
 109   { // second range empty
 110     int a[] = {5, 4, 3, 2, 1};
 111     std::array<int, 0> b = {};
 112     int c[5];
 113
 114     auto range1 = std::ranges::subrange(In1(a), Sent1(In1(a + 5)));
 115     auto range2 = std::ranges::subrange(In2(b.data()), Sent2(In2(b.data())));
 116
 117     auto ret = std::ranges::transform(range1, range2, Out(c), [](int i, int j) { return i + j; });
 118
 119     assert(base(ret.in1) == a);
 120     assert(base(ret.in2) == b.data());
 121     assert(base(ret.out) == c);
 122   }
 123
 124   { // both ranges empty
 125     std::array<int, 0> a = {};
 126     std::array<int, 0> b = {};
 127     int c[5];
 128
 129     auto range1 = std::ranges::subrange(In1(a.data()), Sent1(In1(a.data())));
 130     auto range2 = std::ranges::subrange(In2(b.data()), Sent2(In2(b.data())));
 131
 132     auto ret = std::ranges::transform(range1, range2, Out(c), [](int i, int j) { return i + j; });
 133
 134     assert(base(ret.in1) == a.data());
 135     assert(base(ret.in2) == b.data());
 136     assert(base(ret.out) == c);
 137   }
 138
 139   { // first range one element
 140     int a[] = {2};
 141     int b[] = {5, 4, 3, 2, 1};
 142     int c[5];
 143
 144     auto range1 = std::ranges::subrange(In1(a), Sent1(In1(a + 1)));
 145     auto range2 = std::ranges::subrange(In2(b), Sent2(In2(b + 5)));
 146
 147     auto ret = std::ranges::transform(range1, range2, Out(c), [](int i, int j) { return i + j; });
 148
 149     assert(c[0] == 7);
 150     assert(base(ret.in1) == a + 1);
 151     assert(base(ret.in2) == b + 1);
 152     assert(base(ret.out) == c + 1);
 153   }
 154
 155   { // second range contains one element
 156     int a[] = {5, 4, 3, 2, 1};
 157     int b[] = {4};
 158     int c[5];
 159
 160     auto range1 = std::ranges::subrange(In1(a), Sent1(In1(a + 5)));
 161     auto range2 = std::ranges::subrange(In2(b), Sent2(In2(b + 1)));
 162
 163     auto ret = std::ranges::transform(range1, range2, Out(c), [](int i, int j) { return i + j; });
 164
 165     assert(c[0] == 9);
 166     assert(base(ret.in1) == a + 1);
 167     assert(base(ret.in2) == b + 1);
 168     assert(base(ret.out) == c + 1);
 169   }
 170
 171   { // check that the transform function and projection call counts are correct
 172     int predCount = 0;
 173     int proj1Count = 0;
 174     int proj2Count = 0;
 175     auto pred = [&](int, int) { ++predCount; return 1; };
 176     auto proj1 = [&](int) { ++proj1Count; return 0; };
 177     auto proj2 = [&](int) { ++proj2Count; return 0; };
 178     int a[] = {1, 2, 3, 4};
 179     int b[] = {1, 2, 3, 4};
 180     std::array<int, 4> c;
 181     auto range1 = std::ranges::subrange(In1(a), Sent1(In1(a + 4)));
 182     auto range2 = std::ranges::subrange(In2(b), Sent2(In2(b + 4)));
 183     std::ranges::transform(range1, range2, Out(c.data()), pred, proj1, proj2);
 184     assert(predCount == 4);
 185     assert(proj1Count == 4);
 186     assert(proj2Count == 4);
 187     assert((c == std::array{1, 1, 1, 1}));
 188   }
 189
 190   return true;
 191 }
 192 // clang-format on
 193
 194 template <class In2, class Out, class Sent2 = In2>
 195 constexpr void test_iterator_in1() {
 196   test_iterators<cpp17_input_iterator<int*>, In2, Out, sentinel_wrapper<cpp17_input_iterator<int*>>, Sent2>();
 197   test_iterators<cpp20_input_iterator<int*>, In2, Out, sentinel_wrapper<cpp20_input_iterator<int*>>, Sent2>();
 198   test_iterators<forward_iterator<int*>, In2, Out, forward_iterator<int*>, Sent2>();
 199   test_iterators<bidirectional_iterator<int*>, In2, Out, bidirectional_iterator<int*>, Sent2>();
 200   test_iterators<random_access_iterator<int*>, In2, Out, random_access_iterator<int*>, Sent2>();
 201   test_iterators<contiguous_iterator<int*>, In2, Out, contiguous_iterator<int*>, Sent2>();
 202   test_iterators<int*, In2, Out, int*, Sent2>();
 203   // static_asserting here to avoid hitting the constant evaluation step limit
 204   static_assert(test_iterators<cpp17_input_iterator<int*>, In2, Out, sentinel_wrapper<cpp17_input_iterator<int*>>, Sent2>());
 205   static_assert(test_iterators<cpp20_input_iterator<int*>, In2, Out, sentinel_wrapper<cpp20_input_iterator<int*>>, Sent2>());
 206   static_assert(test_iterators<forward_iterator<int*>, In2, Out, forward_iterator<int*>, Sent2>());
 207   static_assert(test_iterators<bidirectional_iterator<int*>, In2, Out, bidirectional_iterator<int*>, Sent2>());
 208   static_assert(test_iterators<random_access_iterator<int*>, In2, Out, random_access_iterator<int*>, Sent2>());
 209   static_assert(test_iterators<contiguous_iterator<int*>, In2, Out, contiguous_iterator<int*>, Sent2>());
 210   static_assert(test_iterators<int*, In2, Out, int*, Sent2>());
 211 }
 212
 213 template <class Out>
 214 constexpr void test_iterators_in1_in2() {
 215   test_iterator_in1<cpp17_input_iterator<int*>, Out, sentinel_wrapper<cpp17_input_iterator<int*>>>();
 216   test_iterator_in1<cpp20_input_iterator<int*>, Out, sentinel_wrapper<cpp20_input_iterator<int*>>>();
 217   test_iterator_in1<forward_iterator<int*>, Out>();
 218   test_iterator_in1<bidirectional_iterator<int*>, Out>();
 219   test_iterator_in1<random_access_iterator<int*>, Out>();
 220   test_iterator_in1<contiguous_iterator<int*>, Out>();
 221   test_iterator_in1<int*, Out>();
 222 }
 223
 224 constexpr bool test() {
 225   test_iterators_in1_in2<cpp17_output_iterator<int*>>();
 226   test_iterators_in1_in2<cpp20_output_iterator<int*>>();
 227   test_iterators_in1_in2<forward_iterator<int*>>();
 228   test_iterators_in1_in2<bidirectional_iterator<int*>>();
 229   test_iterators_in1_in2<random_access_iterator<int*>>();
 230   test_iterators_in1_in2<contiguous_iterator<int*>>();
 231   test_iterators_in1_in2<int*>();
 232
 233   { // check that std::ranges::dangling is returned properly
 234     {
 235       int b[] = {2, 5, 4, 3, 1};
 236       std::array<int, 5> c;
 237       std::same_as<std::ranges::in_in_out_result<std::ranges::dangling, int*, int*>> auto ret =
 238           std::ranges::transform(std::array{1, 2, 3, 5, 4}, b, c.data(), [](int i, int j) { return i * j; });
 239       assert((c == std::array{2, 10, 12, 15, 4}));
 240       assert(ret.in2 == b + 5);
 241       assert(ret.out == c.data() + c.size());
 242     }
 243     {
 244       int a[] = {2, 5, 4, 3, 1, 4, 5, 6};
 245       std::array<int, 8> c;
 246       std::same_as<std::ranges::in_in_out_result<int*, std::ranges::dangling, int*>> auto ret =
 247           std::ranges::transform(a, std::array{1, 2, 3, 5, 4, 5, 6, 7}, c.data(), [](int i, int j) { return i * j; });
 248       assert((c == std::array{2, 10, 12, 15, 4, 20, 30, 42}));
 249       assert(ret.in1 == a + 8);
 250       assert(ret.out == c.data() + c.size());
 251     }
 252     {
 253       std::array<int, 3> c;
 254       std::same_as<std::ranges::in_in_out_result<std::ranges::dangling, std::ranges::dangling, int*>> auto ret =
 255           std::ranges::transform(std::array{4, 4, 4}, std::array{4, 4, 4}, c.data(), [](int i, int j) { return i * j; });
 256       assert((c == std::array{16, 16, 16}));
 257       assert(ret.out == c.data() + c.size());
 258     }
 259   }
 260
 261   { // check that returning another type from the projection works
 262     struct S { int i; int other; };
 263     S a[] = { S{0, 0}, S{1, 0}, S{3, 0}, S{10, 0} };
 264     S b[] = { S{0, 10}, S{1, 20}, S{3, 30}, S{10, 40} };
 265     std::array<int, 4> c;
 266     std::ranges::transform(a, b, c.begin(), [](S s1, S s2) { return s1.i + s2.other; });
 267     assert((c == std::array{10, 21, 33, 50}));
 268   }
 269
 270   { // check that std::invoke is used
 271     struct S { int i; };
 272     S a[] = { S{1}, S{3}, S{2} };
 273     S b[] = { S{2}, S{5}, S{3} };
 274     std::array<int, 3> c;
 275     auto ret = std::ranges::transform(a, b, c.data(), [](int i, int j) { return i + j + 2; }, &S::i, &S::i);
 276     assert((c == std::array{5, 10, 7}));
 277     assert(ret.out == c.data() + 3);
 278   }
 279
 280   return true;
 281 }
 282
 283 int main(int, char**) {
 284   test();
 285   static_assert(test());
 286
 287   return 0;
 288 }