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 // UNSUPPORTED: libcpp-no-concepts
11 
12 // constexpr counted_iterator operator+(iter_difference_t<I> n) const
13 //     requires random_access_iterator<I>;
14 // friend constexpr counted_iterator operator+(
15 //   iter_difference_t<I> n, const counted_iterator& x)
16 //     requires random_access_iterator<I>;
17 // constexpr counted_iterator& operator+=(iter_difference_t<I> n)
18 //     requires random_access_iterator<I>;
19 
20 #include <iterator>
21 
22 #include "test_macros.h"
23 #include "test_iterators.h"
24 
25 template<class Iter>
26 concept PlusEnabled = requires(Iter& iter) {
27   iter + 1;
28 };
29 
30 template<class Iter>
31 concept PlusEqEnabled = requires(Iter& iter) {
32   iter += 1;
33 };
34 
35 constexpr bool test() {
36   int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};
37 
38   {
39     {
40       using Counted = std::counted_iterator<random_access_iterator<int*>>;
41       std::counted_iterator iter(random_access_iterator<int*>{buffer}, 8);
42       assert(iter + 2 == Counted(random_access_iterator<int*>{buffer + 2}, 6));
43       assert(iter + 0 == Counted(random_access_iterator<int*>{buffer}, 8));
44 
45       ASSERT_SAME_TYPE(decltype(iter + 2), Counted);
46     }
47     {
48       using Counted = const std::counted_iterator<random_access_iterator<int*>>;
49       const std::counted_iterator iter(random_access_iterator<int*>{buffer}, 8);
50       assert(iter + 8 == Counted(random_access_iterator<int*>{buffer + 8}, 0));
51       assert(iter + 0 == Counted(random_access_iterator<int*>{buffer}, 8));
52 
53       ASSERT_SAME_TYPE(decltype(iter + 2), std::remove_const_t<Counted>);
54     }
55   }
56 
57   {
58     {
59       using Counted = std::counted_iterator<random_access_iterator<int*>>;
60       std::counted_iterator iter(random_access_iterator<int*>{buffer}, 8);
61       assert(2 + iter == Counted(random_access_iterator<int*>{buffer + 2}, 6));
62       assert(0 + iter == Counted(random_access_iterator<int*>{buffer}, 8));
63 
64       ASSERT_SAME_TYPE(decltype(iter + 2), Counted);
65     }
66     {
67       using Counted = const std::counted_iterator<random_access_iterator<int*>>;
68       const std::counted_iterator iter(random_access_iterator<int*>{buffer}, 8);
69       assert(8 + iter == Counted(random_access_iterator<int*>{buffer + 8}, 0));
70       assert(0 + iter == Counted(random_access_iterator<int*>{buffer}, 8));
71 
72       ASSERT_SAME_TYPE(decltype(iter + 2), std::remove_const_t<Counted>);
73     }
74   }
75 
76   {
77     {
78       using Counted = std::counted_iterator<random_access_iterator<int*>>;
79       std::counted_iterator iter(random_access_iterator<int*>{buffer}, 8);
80       assert((iter += 2) == Counted(random_access_iterator<int*>{buffer + 2}, 6));
81       assert((iter += 0) == Counted(random_access_iterator<int*>{buffer + 2}, 6));
82 
83       ASSERT_SAME_TYPE(decltype(iter += 2), Counted&);
84     }
85     {
86       using Counted = std::counted_iterator<contiguous_iterator<int*>>;
87       std::counted_iterator iter(contiguous_iterator<int*>{buffer}, 8);
88       assert((iter += 8) == Counted(contiguous_iterator<int*>{buffer + 8}, 0));
89       assert((iter += 0) == Counted(contiguous_iterator<int*>{buffer + 8}, 0));
90 
91       ASSERT_SAME_TYPE(decltype(iter += 2), Counted&);
92     }
93     {
94       static_assert( PlusEnabled<std::counted_iterator<random_access_iterator<int*>>>);
95       static_assert(!PlusEnabled<std::counted_iterator<bidirectional_iterator<int*>>>);
96 
97       static_assert( PlusEqEnabled<      std::counted_iterator<random_access_iterator<int*>>>);
98       static_assert(!PlusEqEnabled<const std::counted_iterator<random_access_iterator<int*>>>);
99     }
100   }
101 
102   return true;
103 }
104 
105 int main(int, char**) {
106   test();
107   static_assert(test());
108 
109   return 0;
110 }
111