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 // constexpr iter_difference_t<I> count() const noexcept;
12 
13 #include <iterator>
14 
15 #include "test_macros.h"
16 #include "test_iterators.h"
17 
18 struct InputOrOutputArchetype {
19   using difference_type = int;
20 
21   int *ptr;
22 
23   constexpr int operator*() { return *ptr; }
24   constexpr void operator++(int) { ++ptr; }
25   constexpr InputOrOutputArchetype& operator++() { ++ptr; return *this; }
26 };
27 
28 constexpr bool test() {
29   int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};
30 
31   {
32     std::counted_iterator iter(cpp20_input_iterator<int*>{buffer}, 8);
33     for (int i = 8; i != 0; --i, ++iter)
34       assert(iter.count() == i);
35 
36     static_assert(noexcept(iter.count()));
37   }
38   {
39     std::counted_iterator iter(forward_iterator<int*>{buffer}, 8);
40     for (int i = 8; i != 0; --i, ++iter)
41       assert(iter.count() == i);
42 
43     static_assert(noexcept(iter.count()));
44   }
45   {
46     std::counted_iterator iter(contiguous_iterator<int*>{buffer}, 8);
47     for (int i = 8; i != 0; --i, ++iter)
48       assert(iter.count() == i);
49   }
50   {
51     std::counted_iterator iter(InputOrOutputArchetype{buffer + 2}, 6);
52     assert(iter.count() == 6);
53   }
54 
55   // Const tests.
56   {
57     const std::counted_iterator iter(cpp20_input_iterator<int*>{buffer}, 8);
58     assert(iter.count() == 8);
59   }
60   {
61     const std::counted_iterator iter(forward_iterator<int*>{buffer + 1}, 7);
62     assert(iter.count() == 7);
63   }
64   {
65     const std::counted_iterator iter(contiguous_iterator<int*>{buffer + 2}, 6);
66     assert(iter.count() == 6);
67   }
68   {
69     const std::counted_iterator iter(InputOrOutputArchetype{buffer + 2}, 6);
70     assert(iter.count() == 6);
71   }
72 
73   return true;
74 }
75 
76 int main(int, char**) {
77   test();
78   static_assert(test());
79 
80   return 0;
81 }
82