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 // <iterator>
12
13 // reverse_iterator
14
15 // template<class Iterator1, three_way_comparable_with<Iterator1> Iterator2>
16 // constexpr compare_three_way_result_t<Iterator1, Iterator2>
17 // operator<=>(const reverse_iterator<Iterator1>& x,
18 // const reverse_iterator<Iterator2>& y);
19
20 #include <iterator>
21 #include <limits>
22 #include <cassert>
23
24 #include "test_macros.h"
25 #include "test_iterators.h"
26
27 template <class ItL, class ItR, class Ord>
test(ItL l,ItR r,Ord x)28 constexpr void test(ItL l, ItR r, Ord x) {
29 const std::reverse_iterator<ItL> l1(l);
30 const std::reverse_iterator<ItR> r1(r);
31 ASSERT_SAME_TYPE(decltype(l1 <=> r1), Ord);
32 assert((l1 <=> r1) == x);
33 }
34
35 struct Iter {
36 using iterator_category = std::bidirectional_iterator_tag;
37 using pointer = char*;
38 using reference = char&;
39 using value_type = char;
40 using difference_type = double;
41
IterIter42 constexpr Iter(double value): m_value(value) {}
43 double m_value;
44
45 reference operator*() const;
46 private:
47 friend constexpr bool operator==(const Iter& l, const Iter& r) = default;
48 friend constexpr std::partial_ordering operator<=>(const Iter& l, const Iter& r) = default;
49 };
50
51 struct ConstIter {
52 using iterator_category = std::bidirectional_iterator_tag;
53 using pointer = const char*;
54 using reference = const char&;
55 using value_type = const char;
56 using difference_type = double;
57
ConstIterConstIter58 constexpr ConstIter(double value): m_value(value) {}
ConstIterConstIter59 constexpr ConstIter(Iter it): m_value(it.m_value) {}
60 double m_value;
61
62 reference operator*() const;
63 private:
64 friend constexpr bool operator==(const ConstIter& l, const ConstIter& r) = default;
65 friend constexpr std::partial_ordering operator<=>(const ConstIter& l, const ConstIter& r) = default;
66 };
67
tests()68 constexpr bool tests() {
69 char s[] = "1234567890";
70 test(three_way_contiguous_iterator<const char*>(s),
71 three_way_contiguous_iterator<const char*>(s),
72 std::strong_ordering::equal);
73 test(three_way_contiguous_iterator<const char*>(s),
74 three_way_contiguous_iterator<const char*>(s+1),
75 std::strong_ordering::greater);
76 test(three_way_contiguous_iterator<const char*>(s+1),
77 three_way_contiguous_iterator<const char*>(s),
78 std::strong_ordering::less);
79
80 test(s, s, std::strong_ordering::equal);
81 test(s, s+1, std::strong_ordering::greater);
82 test(s+1, s, std::strong_ordering::less);
83
84 const char* cs = s;
85 test(cs, s, std::strong_ordering::equal);
86 test(cs, s+1, std::strong_ordering::greater);
87 test(cs+1, s, std::strong_ordering::less);
88
89 constexpr double nan = std::numeric_limits<double>::quiet_NaN();
90 test(Iter(0), ConstIter(nan), std::partial_ordering::unordered);
91 test(Iter(nan), Iter(nan), std::partial_ordering::unordered);
92 test(ConstIter(0), Iter(1), std::partial_ordering::greater);
93 test(ConstIter(3), Iter(2), std::partial_ordering::less);
94 test(ConstIter(7), Iter(7), std::partial_ordering::equivalent);
95
96 return true;
97 }
98
main(int,char **)99 int main(int, char**) {
100 tests();
101 static_assert(tests());
102 return 0;
103 }
104