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 // friend constexpr iter_difference_t<W> operator-(const iterator& x, const sentinel& y)
12 // requires sized_sentinel_for<Bound, W>;
13 // friend constexpr iter_difference_t<W> operator-(const sentinel& x, const iterator& y)
14 // requires sized_sentinel_for<Bound, W>;
15
16 #include <ranges>
17 #include <cassert>
18
19 #include "test_macros.h"
20 #include "test_iterators.h"
21 #include "../types.h"
22
23 template<class T>
24 concept MinusInvocable = requires(std::ranges::iota_view<T, IntSentinelWith<T>> io) {
25 io.end() - io.begin();
26 };
27
test()28 constexpr bool test() {
29 int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};
30
31 {
32 auto outIter = random_access_iterator<int*>(buffer);
33 std::ranges::iota_view<random_access_iterator<int*>, IntSentinelWith<random_access_iterator<int*>>> io(
34 outIter, IntSentinelWith<random_access_iterator<int*>>(std::ranges::next(outIter, 8)));
35 auto iter = io.begin();
36 auto sent = io.end();
37 assert(iter - sent == -8);
38 assert(sent - iter == 8);
39 }
40 {
41 auto outIter = random_access_iterator<int*>(buffer);
42 const std::ranges::iota_view<random_access_iterator<int*>, IntSentinelWith<random_access_iterator<int*>>> io(
43 outIter, IntSentinelWith<random_access_iterator<int*>>(std::ranges::next(outIter, 8)));
44 const auto iter = io.begin();
45 const auto sent = io.end();
46 assert(iter - sent == -8);
47 assert(sent - iter == 8);
48 }
49
50 {
51 // The minus operator requires that "W" is an input_or_output_iterator.
52 static_assert(!MinusInvocable<int>);
53 }
54
55 return true;
56 }
57
main(int,char **)58 int main(int, char**) {
59 test();
60 static_assert(test());
61
62 return 0;
63 }
64