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<range R>
12// constexpr range_difference_t<R> ranges::distance(R&& r);
13
14#include <iterator>
15#include <cassert>
16#include <ranges>
17
18#include "test_iterators.h"
19#include "test_macros.h"
20
21template<class It, class Sent>
22constexpr void test_ordinary() {
23 struct R {
24 mutable int a[3] = {1, 2, 3};
25 constexpr It begin() const { return It(a); }
26 constexpr Sent end() const { return Sent(It(a + 3)); }
27 };
28 R r;
29 assert(std::ranges::distance(r) == 3);
30 assert(std::ranges::distance(static_cast<R&&>(r)) == 3);
31 assert(std::ranges::distance(static_cast<const R&>(r)) == 3);
32 assert(std::ranges::distance(static_cast<const R&&>(r)) == 3);
33 ASSERT_SAME_TYPE(decltype(std::ranges::distance(r)), std::ranges::range_difference_t<R>);
34}
35
36constexpr bool test() {
37 {
38 using R = int[3];
39 int a[] = {1, 2, 3};
40 assert(std::ranges::distance(static_cast<R&>(a)) == 3);
41 assert(std::ranges::distance(static_cast<R&&>(a)) == 3);
42 assert(std::ranges::distance(static_cast<const R&>(a)) == 3);
43 assert(std::ranges::distance(static_cast<const R&&>(a)) == 3);
44 ASSERT_SAME_TYPE(decltype(std::ranges::distance(a)), std::ptrdiff_t);
45 ASSERT_SAME_TYPE(decltype(std::ranges::distance(a)), std::ranges::range_difference_t<R>);
46 }
47 {
48 // Unsized range, non-copyable iterator type, rvalue-ref-qualified begin()
49 using It = cpp20_input_iterator<int*>;
50 using Sent = sentinel_wrapper<cpp20_input_iterator<int*>>;
51 using R = std::ranges::subrange<It, Sent, std::ranges::subrange_kind::unsized>;
52
53 int a[] = {1, 2, 3};
54 {
55 auto r = R(It(a), Sent(It(a + 3)));
56 assert(std::ranges::distance(r) == 3);
57 }
58 {
59 auto r = R(It(a), Sent(It(a + 3)));
60 assert(std::ranges::distance(static_cast<R&&>(r)) == 3);
61 }
62 static_assert(!std::is_invocable_v<decltype(std::ranges::distance), const R&>);
63 static_assert(!std::is_invocable_v<decltype(std::ranges::distance), const R&&>);
64 }
65 {
66 // Sized range (unsized sentinel type), non-copyable iterator type, rvalue-ref-qualified begin()
67 using It = cpp20_input_iterator<int*>;
68 using Sent = sentinel_wrapper<cpp20_input_iterator<int*>>;
69 using R = std::ranges::subrange<It, Sent, std::ranges::subrange_kind::sized>;
70
71 int a[] = {1, 2, 3};
72 {
73 auto r = R(It(a), Sent(It(a + 3)), 3);
74 assert(std::ranges::distance(r) == 3);
75 }
76 {
77 auto r = R(It(a), Sent(It(a + 3)), 3);
78 assert(std::ranges::distance(static_cast<R&&>(r)) == 3);
79 }
80 static_assert(!std::is_invocable_v<decltype(std::ranges::distance), const R&>);
81 static_assert(!std::is_invocable_v<decltype(std::ranges::distance), const R&&>);
82 }
83 {
84 // Sized range (sized sentinel type), non-copyable iterator type
85 test_ordinary<cpp20_input_iterator<int*>, sized_sentinel<cpp20_input_iterator<int*>>>();
86 }
87 test_ordinary<cpp17_input_iterator<int*>, sentinel_wrapper<cpp17_input_iterator<int*>>>();
88 test_ordinary<cpp20_input_iterator<int*>, sentinel_wrapper<cpp20_input_iterator<int*>>>();
89 test_ordinary<cpp17_output_iterator<int*>, sentinel_wrapper<cpp17_output_iterator<int*>>>();
90 test_ordinary<forward_iterator<int*>, sentinel_wrapper<forward_iterator<int*>>>();
91 test_ordinary<bidirectional_iterator<int*>, sentinel_wrapper<bidirectional_iterator<int*>>>();
92 test_ordinary<random_access_iterator<int*>, sentinel_wrapper<random_access_iterator<int*>>>();
93 test_ordinary<contiguous_iterator<int*>, sentinel_wrapper<contiguous_iterator<int*>>>();
94 test_ordinary<int*, sentinel_wrapper<int*>>();
95
96 test_ordinary<cpp17_input_iterator<int*>, sized_sentinel<cpp17_input_iterator<int*>>>();
97 test_ordinary<cpp20_input_iterator<int*>, sized_sentinel<cpp20_input_iterator<int*>>>();
98 test_ordinary<cpp17_output_iterator<int*>, sized_sentinel<cpp17_output_iterator<int*>>>();
99 test_ordinary<forward_iterator<int*>, sized_sentinel<forward_iterator<int*>>>();
100 test_ordinary<bidirectional_iterator<int*>, sized_sentinel<bidirectional_iterator<int*>>>();
101 test_ordinary<random_access_iterator<int*>, sized_sentinel<random_access_iterator<int*>>>();
102 test_ordinary<contiguous_iterator<int*>, sized_sentinel<contiguous_iterator<int*>>>();
103 test_ordinary<int*, sized_sentinel<int*>>();
104 test_ordinary<int*, int*>();
105
106 // Calling it on a non-range isn't allowed.
107 static_assert(!std::is_invocable_v<decltype(std::ranges::distance), int>);
108 static_assert(!std::is_invocable_v<decltype(std::ranges::distance), int*>);
109
110 return true;
111}
112
113int main(int, char**) {
114 test();
115 static_assert(test());
116
117 return 0;
118}
119

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