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 // template<common_with<I> I2>
12 // friend constexpr strong_ordering operator<=>(
13 // const counted_iterator& x, const counted_iterator<I2>& y);
14
15 #include <iterator>
16
17 #include "test_macros.h"
18 #include "test_iterators.h"
19
20 // This iterator is common_with forward_iterator but NOT comparable with it.
21 template <class It>
22 class CommonWithForwardIter
23 {
24 It it_;
25
26 public:
27 typedef std::input_iterator_tag iterator_category;
28 typedef typename std::iterator_traits<It>::value_type value_type;
29 typedef typename std::iterator_traits<It>::difference_type difference_type;
30 typedef It pointer;
31 typedef typename std::iterator_traits<It>::reference reference;
32
base() const33 constexpr It base() const {return it_;}
34
35 CommonWithForwardIter() = default;
CommonWithForwardIter(It it)36 explicit constexpr CommonWithForwardIter(It it) : it_(it) {}
CommonWithForwardIter(const forward_iterator<It> & it)37 constexpr CommonWithForwardIter(const forward_iterator<It>& it) : it_(it.base()) {}
38
operator *() const39 constexpr reference operator*() const {return *it_;}
40
operator ++()41 constexpr CommonWithForwardIter& operator++() {++it_; return *this;}
operator ++(int)42 constexpr CommonWithForwardIter operator++(int)
43 {CommonWithForwardIter tmp(*this); ++(*this); return tmp;}
44 };
45
test()46 constexpr bool test() {
47 int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};
48
49 auto& Eq = std::strong_ordering::equal;
50 auto& Less = std::strong_ordering::less;
51 auto& Greater = std::strong_ordering::greater;
52
53 {
54 {
55 std::counted_iterator iter1(forward_iterator<int*>(buffer), 8);
56 std::counted_iterator iter2(CommonWithForwardIter<int*>(buffer), 8);
57
58 assert((iter1 <=> iter2) == Eq);
59 assert((iter2 <=> iter1) == Eq);
60 ++iter1;
61 assert((iter1 <=> iter2) == Greater);
62 assert((iter2 <=> iter1) == Less);
63 }
64 {
65 std::counted_iterator iter1(forward_iterator<int*>(buffer), 8);
66 std::counted_iterator iter2(forward_iterator<int*>(buffer), 8);
67
68 assert((iter1 <=> iter2) == Eq);
69 assert((iter2 <=> iter1) == Eq);
70 ++iter1;
71 assert((iter1 <=> iter2) == Greater);
72 assert((iter2 <=> iter1) == Less);
73 }
74 }
75
76
77 return true;
78 }
79
main(int,char **)80 int main(int, char**) {
81 test();
82 static_assert(test());
83
84 return 0;
85 }
86