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<class I, sentinel_for<I> S>
12// requires (!sized_sentinel_for<S, I>)
13// constexpr iter_difference_t<I> ranges::distance(I first, S last);
14//
15// template<class I, sized_sentinel_for<decay_t<I>> S>
16// constexpr iter_difference_t<I> ranges::distance(const I& first, S last);
17
18#include <iterator>
19#include <cassert>
20
21#include "test_iterators.h"
22
23template<class It>
24struct EvilSentinel {
25 It p_;
26 friend constexpr bool operator==(EvilSentinel s, It p) { return s.p_ == p; }
27 friend constexpr auto operator-(EvilSentinel s, It p) { return s.p_ - p; }
28 friend constexpr auto operator-(It p, EvilSentinel s) { return p - s.p_; }
29 friend constexpr void operator-(EvilSentinel s, int(&)[3]) = delete;
30 friend constexpr void operator-(EvilSentinel s, int(&&)[3]) = delete;
31 friend constexpr void operator-(EvilSentinel s, const int(&)[3]) = delete;
32 friend constexpr void operator-(EvilSentinel s, const int(&&)[3]) = delete;
33};
34static_assert( std::sized_sentinel_for<EvilSentinel<int*>, int*>);
35static_assert(!std::sized_sentinel_for<EvilSentinel<int*>, const int*>);
36static_assert( std::sized_sentinel_for<EvilSentinel<const int*>, int*>);
37static_assert( std::sized_sentinel_for<EvilSentinel<const int*>, const int*>);
38
39constexpr bool test() {
40 {
41 int a[] = {1, 2, 3};
42 assert(std::ranges::distance(a, a + 3) == 3);
43 assert(std::ranges::distance(a, a) == 0);
44 assert(std::ranges::distance(a + 3, a) == -3);
45 }
46 {
47 int a[] = {1, 2, 3};
48 assert(std::ranges::distance(a, EvilSentinel<int*>{a+3}) == 3);
49 assert(std::ranges::distance(a, EvilSentinel<int*>{a}) == 0);
50 assert(std::ranges::distance(a+3, EvilSentinel<int*>{a}) == -3);
51 assert(std::ranges::distance(std::move(a), EvilSentinel<int*>{a+3}) == 3);
52 }
53 {
54 const int a[] = {1, 2, 3};
55 assert(std::ranges::distance(a, EvilSentinel<const int*>{a+3}) == 3);
56 assert(std::ranges::distance(a, EvilSentinel<const int*>{a}) == 0);
57 assert(std::ranges::distance(a+3, EvilSentinel<const int*>{a}) == -3);
58 assert(std::ranges::distance(std::move(a), EvilSentinel<const int*>{a+3}) == 3);
59 static_assert(!std::is_invocable_v<decltype(std::ranges::distance), const int(&)[3], EvilSentinel<int*>>);
60 static_assert(!std::is_invocable_v<decltype(std::ranges::distance), const int(&&)[3], EvilSentinel<int*>>);
61 }
62
63 return true;
64}
65
66int main(int, char**) {
67 test();
68 static_assert(test());
69
70 return 0;
71}
72

source code of libcxx/test/std/iterators/iterator.primitives/range.iter.ops/range.iter.ops.distance/lwg3664.pass.cpp