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-has-no-incomplete-ranges
11
12 // template<class I, sentinel_for<I> S>
13 // requires (!sized_sentinel_for<S, I>)
14 // constexpr iter_difference_t<I> ranges::distance(I first, S last);
15 //
16 // template<class I, sized_sentinel_for<decay_t<I>> S>
17 // constexpr iter_difference_t<I> ranges::distance(const I& first, S last);
18
19 #include <iterator>
20 #include <cassert>
21
22 #include "test_iterators.h"
23
24 template<class It>
25 struct EvilSentinel {
26 It p_;
operator ==(EvilSentinel s,It p)27 friend constexpr bool operator==(EvilSentinel s, It p) { return s.p_ == p; }
operator -(EvilSentinel s,It p)28 friend constexpr auto operator-(EvilSentinel s, It p) { return s.p_ - p; }
operator -(It p,EvilSentinel s)29 friend constexpr auto operator-(It p, EvilSentinel s) { return p - s.p_; }
30 friend constexpr void operator-(EvilSentinel s, int(&)[3]) = delete;
31 friend constexpr void operator-(EvilSentinel s, int(&&)[3]) = delete;
32 friend constexpr void operator-(EvilSentinel s, const int(&)[3]) = delete;
33 friend constexpr void operator-(EvilSentinel s, const int(&&)[3]) = delete;
34 };
35 static_assert( std::sized_sentinel_for<EvilSentinel<int*>, int*>);
36 static_assert(!std::sized_sentinel_for<EvilSentinel<int*>, const int*>);
37 static_assert( std::sized_sentinel_for<EvilSentinel<const int*>, int*>);
38 static_assert( std::sized_sentinel_for<EvilSentinel<const int*>, const int*>);
39
test()40 constexpr bool test() {
41 {
42 int a[] = {1, 2, 3};
43 assert(std::ranges::distance(a, a + 3) == 3);
44 assert(std::ranges::distance(a, a) == 0);
45 assert(std::ranges::distance(a + 3, a) == -3);
46 }
47 {
48 int a[] = {1, 2, 3};
49 assert(std::ranges::distance(a, EvilSentinel<int*>{a+3}) == 3);
50 assert(std::ranges::distance(a, EvilSentinel<int*>{a}) == 0);
51 assert(std::ranges::distance(a+3, EvilSentinel<int*>{a}) == -3);
52 assert(std::ranges::distance(std::move(a), EvilSentinel<int*>{a+3}) == 3);
53 }
54 {
55 const int a[] = {1, 2, 3};
56 assert(std::ranges::distance(a, EvilSentinel<const int*>{a+3}) == 3);
57 assert(std::ranges::distance(a, EvilSentinel<const int*>{a}) == 0);
58 assert(std::ranges::distance(a+3, EvilSentinel<const int*>{a}) == -3);
59 assert(std::ranges::distance(std::move(a), EvilSentinel<const int*>{a+3}) == 3);
60 static_assert(!std::is_invocable_v<decltype(std::ranges::distance), const int(&)[3], EvilSentinel<int*>>);
61 static_assert(!std::is_invocable_v<decltype(std::ranges::distance), const int(&&)[3], EvilSentinel<int*>>);
62 }
63
64 return true;
65 }
66
main(int,char **)67 int main(int, char**) {
68 test();
69 static_assert(test());
70
71 return 0;
72 }
73