libcxx/test/std/algorithms/alg.nonmodifying/alg.starts_with/ranges.starts_with.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, c++20
  12
  13 // template<input_iterator I1, sentinel_for<I1> S1, input_iterator I2, sentinel_for<I2> S2,
  14 //          class Pred = ranges::equal_to, class Proj1 = identity, class Proj2 = identity>
  15 //   requires indirectly_comparable<I1, I2, Pred, Proj1, Proj2>
  16 //   constexpr bool ranges::starts_with(I1 first1, S1 last1, I2 first2, S2 last2, Pred pred = {},
  17 //                                      Proj1 proj1 = {}, Proj2 proj2 = {});
  18 // template<input_range R1, input_range R2, class Pred = ranges::equal_to, class Proj1 = identity,
  19 //          class Proj2 = identity>
  20 //   requires indirectly_comparable<iterator_t<R1>, iterator_t<R2>, Pred, Proj1, Proj2>
  21 //   constexpr bool ranges::starts_with(R1&& r1, R2&& r2, Pred pred = {},
  22 //                                      Proj1 proj1 = {}, Proj2 proj2 = {});
  23
  24 #include <algorithm>
  25 #include <array>
  26 #include <ranges>
  27
  28 #include "almost_satisfies_types.h"
  29 #include "test_iterators.h"
  30
  31 template <class Iter1, class Sent1 = Iter1, class Iter2 = int*, class Sent2 = Iter2>
  32 concept HasStartsWithIt = requires(Iter1 first1, Sent1 last1, Iter2 first2, Sent2 last2) {
  33   std::ranges::starts_with(first1, last1, first2, last2);
  34 };
  35
  36 static_assert(HasStartsWithIt<int*>);
  37 static_assert(HasStartsWithIt<ForwardIteratorNotDerivedFrom>);
  38 static_assert(HasStartsWithIt<ForwardIteratorNotIncrementable>);
  39 static_assert(!HasStartsWithIt<int*, SentinelForNotSemiregular>);
  40 static_assert(!HasStartsWithIt<int*, int*, int**>); // not indirectly comparable
  41 static_assert(!HasStartsWithIt<int*, SentinelForNotWeaklyEqualityComparableWith>);
  42 static_assert(HasStartsWithIt<int*, int*, ForwardIteratorNotDerivedFrom>);
  43 static_assert(HasStartsWithIt<int*, int*, ForwardIteratorNotIncrementable>);
  44 static_assert(!HasStartsWithIt<int*, int*, int*, SentinelForNotSemiregular>);
  45 static_assert(!HasStartsWithIt<int*, int*, int*, SentinelForNotWeaklyEqualityComparableWith>);
  46
  47 template <class Range1, class Range2 = UncheckedRange<int*>>
  48 concept HasStartsWithR = requires(Range1 range1, Range2 range2) { std::ranges::starts_with(range1, range2); };
  49
  50 static_assert(HasStartsWithR<UncheckedRange<int*>>);
  51 static_assert(HasStartsWithR<ForwardRangeNotDerivedFrom>);
  52 static_assert(!HasStartsWithR<ForwardIteratorNotIncrementable>);
  53 static_assert(!HasStartsWithR<ForwardRangeNotSentinelSemiregular>);
  54 static_assert(!HasStartsWithR<ForwardRangeNotSentinelEqualityComparableWith>);
  55 static_assert(!HasStartsWithR<UncheckedRange<int*>, UncheckedRange<int**>>); // not indirectly comparable
  56 static_assert(HasStartsWithR<UncheckedRange<int*>, ForwardRangeNotDerivedFrom>);
  57 static_assert(HasStartsWithR<UncheckedRange<int*>, ForwardRangeNotIncrementable>);
  58 static_assert(!HasStartsWithR<UncheckedRange<int*>, ForwardRangeNotSentinelSemiregular>);
  59 static_assert(!HasStartsWithR<UncheckedRange<int*>, ForwardRangeNotSentinelEqualityComparableWith>);
  60
  61 // clang-format off
  62 template <class Iter1, class Sent1 = Iter1, class Iter2, class Sent2 = Iter2>
  63 constexpr void test_iterators() {
  64   {  // simple tests
  65     {
  66       int a[] = {1, 2, 3, 4, 5, 6};
  67       int p[] = {1, 2};
  68       std::same_as<bool> decltype(auto) ret =
  69         std::ranges::starts_with(Iter1(a), Sent1(Iter1(a + 6)), Iter2(p), Sent2(Iter2(p + 2)));
  70       assert(ret);
  71     }
  72     {
  73       int a[]                               = {1, 2, 3, 4, 5, 6};
  74       int p[]                               = {1, 2};
  75       auto whole                            = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 6)));
  76       auto prefix                           = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 2)));
  77       std::same_as<bool> decltype(auto) ret = std::ranges::starts_with(whole, prefix);
  78       assert(ret);
  79     }
  80   }
  81
  82   { // prefix doesn't match
  83     {
  84       int a[] = {1, 2, 3, 4, 5, 6};
  85       int p[] = {4, 5, 6};
  86       std::same_as<bool> decltype(auto) ret =
  87           std::ranges::starts_with(Iter1(a), Sent1(Iter1(a + 6)), Iter2(p), Sent2(Iter2(p + 3)));
  88       assert(!ret);
  89     }
  90     {
  91       int a[]                               = {1, 2, 3, 4, 5, 6};
  92       int p[]                               = {4, 5, 6};
  93       auto whole                            = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 6)));
  94       auto prefix                           = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 3)));
  95       std::same_as<bool> decltype(auto) ret = std::ranges::starts_with(whole, prefix);
  96       assert(!ret);
  97     }
  98   }
  99
 100   { // range and prefix are identical
 101     {
 102       int a[] = {1, 2, 3, 4, 5, 6};
 103       int p[] = {1, 2, 3, 4, 5, 6};
 104       std::same_as<bool> decltype(auto) ret =
 105           std::ranges::starts_with(Iter1(a), Sent1(Iter1(a + 6)), Iter2(p), Sent2(Iter2(p + 6)));
 106       assert(ret);
 107     }
 108     {
 109       int a[]                               = {1, 2, 3, 4, 5, 6};
 110       int p[]                               = {1, 2, 3, 4, 5, 6};
 111       auto whole                            = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 6)));
 112       auto prefix                           = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 6)));
 113       std::same_as<bool> decltype(auto) ret = std::ranges::starts_with(whole, prefix);
 114       assert(ret);
 115     }
 116   }
 117
 118   { // prefix is longer than range
 119     {
 120       int a[] = {1, 2, 3, 4, 5, 6};
 121       int p[] = {1, 2, 3, 4, 5, 6, 7, 8};
 122       std::same_as<bool> decltype(auto) ret =
 123           std::ranges::starts_with(Iter1(a), Sent1(Iter1(a + 6)), Iter2(p), Sent2(Iter2(p + 8)));
 124       assert(!ret);
 125     }
 126     {
 127       int a[]                               = {1, 2, 3, 4, 5, 6};
 128       int p[]                               = {1, 2, 3, 4, 5, 6, 7, 8};
 129       auto whole                            = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 6)));
 130       auto prefix                           = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 8)));
 131       std::same_as<bool> decltype(auto) ret = std::ranges::starts_with(whole, prefix);
 132       assert(!ret);
 133     }
 134   }
 135
 136   { // prefix has zero length
 137     {
 138       int a[] = {1, 2, 3, 4, 5, 6};
 139       std::array<int, 0> p = {};
 140       std::same_as<bool> decltype(auto) ret =
 141           std::ranges::starts_with(Iter1(a), Sent1(Iter1(a + 6)), Iter2(p.data()), Sent2(Iter2(p.data())));
 142       assert(ret);
 143     }
 144     {
 145       int a[]                               = {1, 2, 3, 4, 5, 6};
 146       std::array<int, 0> p = {};
 147       auto whole                            = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 6)));
 148       auto prefix                           = std::ranges::subrange(Iter2(p.data()), Sent2(Iter2(p.data())));
 149       std::same_as<bool> decltype(auto) ret = std::ranges::starts_with(whole, prefix);
 150       assert(ret);
 151     }
 152   }
 153
 154   { // range has zero length
 155     {
 156       std::array<int, 0> a = {};
 157       int p[] = {1, 2, 3, 4, 5, 6, 7, 8};
 158       std::same_as<bool> decltype(auto) ret =
 159           std::ranges::starts_with(Iter1(a.data()), Sent1(Iter1(a.data())), Iter2(p), Sent2(Iter2(p + 8)));
 160       assert(!ret);
 161     }
 162     {
 163       std::array<int, 0> a = {};
 164       int p[]                               = {1, 2, 3, 4, 5, 6, 7, 8};
 165       auto whole                            = std::ranges::subrange(Iter1(a.data()), Sent1(Iter1(a.data())));
 166       auto prefix                           = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 8)));
 167       std::same_as<bool> decltype(auto) ret = std::ranges::starts_with(whole, prefix);
 168       assert(!ret);
 169     }
 170   }
 171
 172   { // check that the predicate is used
 173     {
 174       int a[] = {11, 8, 3, 4, 0, 6};
 175       int p[]                               = {1, 12};
 176       std::same_as<bool> decltype(auto) ret = std::ranges::starts_with(
 177           Iter1(a), Sent1(Iter1(a + 6)), Iter2(p), Sent2(Iter2(p + 2)), [](int l, int r) { return l > r; });
 178       assert(!ret);
 179     }
 180     {
 181       int a[]                               = {11, 8, 3, 4, 0, 6};
 182       int p[]                               = {1, 12};
 183       auto whole                            = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 6)));
 184       auto prefix                           = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 2)));
 185       std::same_as<bool> decltype(auto) ret = std::ranges::starts_with(whole, prefix, [](int l, int r) { return l > r; });
 186       assert(!ret);
 187     }
 188   }
 189
 190   { // check that the projections are used
 191     {
 192       int a[]                               = {1, 3, 5, 1, 5, 6};
 193       int p[]                               = {2, 3, 4};
 194       std::same_as<bool> decltype(auto) ret = std::ranges::starts_with(
 195           Iter1(a),
 196           Sent1(Iter1(a + 6)),
 197           Iter2(p),
 198           Sent2(Iter2(p + 3)),
 199           {},
 200           [](int i) { return i + 3; },
 201           [](int i) { return i * 2; });
 202       assert(ret);
 203     }
 204     {
 205       int a[]                               = {1, 3, 5, 1, 5, 6};
 206       int p[]                               = {2, 3, 4};
 207       auto whole                            = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 6)));
 208       auto prefix                           = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 3)));
 209       std::same_as<bool> decltype(auto) ret = std::ranges::starts_with(
 210           whole, prefix, {}, [](int i) { return i + 3; }, [](int i) { return i * 2; });
 211       assert(ret);
 212     }
 213   }
 214 }
 215
 216 constexpr bool test() {
 217   types::for_each(types::cpp20_input_iterator_list<int*>{}, []<class Iter2>() {
 218     types::for_each(types::cpp20_input_iterator_list<int*>{}, []<class Iter1>() {
 219       if constexpr (std::forward_iterator<Iter1> && std::forward_iterator<Iter2>)
 220         test_iterators<Iter1, Iter1, Iter2, Iter2>();
 221       if constexpr (std::forward_iterator<Iter2>)
 222         test_iterators<Iter1, sized_sentinel<Iter1>, Iter2, Iter2>();
 223       if constexpr (std::forward_iterator<Iter1>)
 224         test_iterators<Iter1, Iter1, Iter2, sized_sentinel<Iter2>>();
 225       test_iterators<Iter1, sized_sentinel<Iter1>, Iter2, sized_sentinel<Iter2>>();
 226     });
 227   });
 228
 229   { // check that std::invoke is used
 230     struct S {
 231       int i;
 232
 233       constexpr S identity() { return *this; }
 234
 235       constexpr bool compare(const S& s) { return i == s.i; }
 236     };
 237     {
 238       S a[]    = {{1}, {2}, {3}, {4}};
 239       S p[]    = {{1}, {2}};
 240       auto ret = std::ranges::starts_with(a, a + 4, p, p + 2, &S::compare, &S::identity, &S::identity);
 241       assert(ret);
 242     }
 243     {
 244       S a[]    = {{1}, {2}, {3}, {4}};
 245       S p[]    = {{1}, {2}};
 246       auto ret = std::ranges::starts_with(a, p, &S::compare, &S::identity, &S::identity);
 247       assert(ret);
 248     }
 249   }
 250
 251   return true;
 252 }
 253
 254 int main(int, char**) {
 255   test();
 256   static_assert(test());
 257
 258   return 0;
 259 }