1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
|
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++03, c++11, c++14, c++17
// friend constexpr bool operator==(const iterator& x, const iterator& y)
// requires equality_comparable<iterator_t<Base>>;
// friend constexpr bool operator<(const iterator& x, const iterator& y)
// requires random_access_range<Base>;
// friend constexpr bool operator>(const iterator& x, const iterator& y)
// requires random_access_range<Base>;
// friend constexpr bool operator<=(const iterator& x, const iterator& y)
// requires random_access_range<Base>;
// friend constexpr bool operator>=(const iterator& x, const iterator& y)
// requires random_access_range<Base>;
// friend constexpr auto operator<=>(const iterator& x, const iterator& y)
// requires random_access_range<Base> && three_way_comparable<iterator_t<Base>>;
#include <compare>
#include <functional>
#include <ranges>
#include <tuple>
#include "test_iterators.h"
#include "test_range.h"
constexpr void compareOperatorTest(const auto& iter1, const auto& iter2) {
assert(!(iter1 < iter1));
assert(iter1 < iter2);
assert(!(iter2 < iter1));
assert(iter1 <= iter1);
assert(iter1 <= iter2);
assert(!(iter2 <= iter1));
assert(!(iter1 > iter1));
assert(!(iter1 > iter2));
assert(iter2 > iter1);
assert(iter1 >= iter1);
assert(!(iter1 >= iter2));
assert(iter2 >= iter1);
assert(iter1 == iter1);
assert(!(iter1 == iter2));
assert(iter2 == iter2);
assert(!(iter1 != iter1));
assert(iter1 != iter2);
assert(!(iter2 != iter2));
}
constexpr void inequalityOperatorsDoNotExistTest(const auto& iter1, const auto& iter2) {
using Iter1 = decltype(iter1);
using Iter2 = decltype(iter2);
static_assert(!std::is_invocable_v<std::less<>, Iter1, Iter2>);
static_assert(!std::is_invocable_v<std::less_equal<>, Iter1, Iter2>);
static_assert(!std::is_invocable_v<std::greater<>, Iter1, Iter2>);
static_assert(!std::is_invocable_v<std::greater_equal<>, Iter1, Iter2>);
}
constexpr bool test() {
std::tuple<int> ts[] = {{1}, {2}, {3}};
{
// Test a new-school iterator with operator<=>; the iterator should also have operator<=>.
using It = three_way_contiguous_iterator<std::tuple<int>*>;
using Subrange = std::ranges::subrange<It>;
static_assert(std::three_way_comparable<It>);
using R = std::ranges::elements_view<Subrange, 0>;
static_assert(std::three_way_comparable<std::ranges::iterator_t<R>>);
auto ev = Subrange{It{&ts[0]}, It{&ts[0] + 3}} | std::views::elements<0>;
auto iter1 = ev.begin();
auto iter2 = iter1 + 1;
compareOperatorTest(iter1, iter2);
assert((iter1 <=> iter2) == std::strong_ordering::less);
assert((iter1 <=> iter1) == std::strong_ordering::equal);
assert((iter2 <=> iter1) == std::strong_ordering::greater);
}
{
// Test an old-school iterator with no operator<=>; the elements view iterator shouldn't have
// operator<=> either.
using It = random_access_iterator<std::tuple<int>*>;
using Subrange = std::ranges::subrange<It>;
static_assert(!std::three_way_comparable<It>);
using R = std::ranges::elements_view<Subrange, 0>;
static_assert(!std::three_way_comparable<std::ranges::iterator_t<R>>);
auto ev = Subrange{It{&ts[0]}, It{&ts[0] + 3}} | std::views::elements<0>;
auto iter1 = ev.begin();
auto iter2 = iter1 + 1;
compareOperatorTest(iter1, iter2);
}
{
// non random_access_range
using It = bidirectional_iterator<std::tuple<int>*>;
using Subrange = std::ranges::subrange<It>;
static_assert(!std::ranges::random_access_range<Subrange>);
using R = std::ranges::elements_view<Subrange, 0>;
static_assert(!std::three_way_comparable<std::ranges::iterator_t<R>>);
auto ev = Subrange{It{&ts[0]}, It{&ts[0] + 1}} | std::views::elements<0>;
auto it1 = ev.begin();
auto it2 = ev.end();
assert(it1 == it1);
assert(!(it1 != it1));
assert(it2 == it2);
assert(!(it2 != it2));
assert(it1 != it2);
++it1;
assert(it1 == it2);
inequalityOperatorsDoNotExistTest(it1, it2);
}
{
// underlying iterator does not support ==
using Iter = cpp20_input_iterator<std::tuple<int>*>;
using Sent = sentinel_wrapper<Iter>;
using Subrange = std::ranges::subrange<Iter, Sent>;
using R = std::ranges::elements_view<Subrange, 0>;
static_assert(!std::three_way_comparable<std::ranges::iterator_t<R>>);
auto ev = Subrange{Iter{&ts[0]}, Sent{Iter{&ts[0] + 1}}} | std::views::elements<0>;
auto it = ev.begin();
using ElemIter = decltype(it);
static_assert(!weakly_equality_comparable_with<ElemIter, ElemIter>);
inequalityOperatorsDoNotExistTest(it, it);
}
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
|
