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 // constexpr auto begin();
12 // constexpr auto begin() const requires range<const V>;
13
14 #include <ranges>
15
16 #include <cassert>
17 #include <concepts>
18 #include <utility>
19
20 #include "test_iterators.h"
21 #include "types.h"
22
23 struct MutableView : std::ranges::view_base {
24 int* begin();
25 sentinel_wrapper<int*> end();
26 };
27
28 template<class View>
29 concept BeginEnabled = requires(View v) { v.begin(); };
30
test()31 constexpr bool test() {
32 int buf[8] = {1, 2, 3, 4, 5, 6, 7, 8};
33
34 {
35 static_assert( BeginEnabled<std::ranges::common_view<CopyableView> const&>);
36 static_assert( BeginEnabled<std::ranges::common_view<MutableView>&>);
37 static_assert(!BeginEnabled<std::ranges::common_view<MutableView> const&>);
38 }
39
40 {
41 SizedRandomAccessView view{buf, buf + 8};
42 std::ranges::common_view<SizedRandomAccessView> common(view);
43 std::same_as<RandomAccessIter> auto begin = common.begin();
44 assert(begin == std::ranges::begin(view));
45 }
46
47 {
48 SizedRandomAccessView view{buf, buf + 8};
49 std::ranges::common_view<SizedRandomAccessView> const common(view);
50 std::same_as<RandomAccessIter> auto begin = common.begin();
51 assert(begin == std::ranges::begin(view));
52 }
53
54 return true;
55 }
56
main(int,char **)57 int main(int, char**) {
58 test();
59 static_assert(test());
60
61 // The non-constexpr tests:
62 int buf[8] = {1, 2, 3, 4, 5, 6, 7, 8};
63
64 {
65 SizedForwardView view{buf, buf + 8};
66 std::ranges::common_view<SizedForwardView> common(view);
67 using CommonIter = std::common_iterator<ForwardIter, sized_sentinel<ForwardIter>>;
68 std::same_as<CommonIter> auto begin = common.begin();
69 assert(begin == std::ranges::begin(view));
70 std::same_as<CommonIter> auto cbegin = std::as_const(common).begin();
71 assert(cbegin == std::ranges::begin(view));
72 }
73
74 {
75 MoveOnlyView view{buf, buf + 8};
76 std::ranges::common_view<MoveOnlyView> common(std::move(view));
77 using CommonIter = std::common_iterator<int*, sentinel_wrapper<int*>>;
78 std::same_as<CommonIter> auto begin = common.begin();
79 assert(begin == std::ranges::begin(view));
80 }
81
82 {
83 CopyableView view{buf, buf + 8};
84 std::ranges::common_view<CopyableView> const common(view);
85 using CommonIter = std::common_iterator<int*, sentinel_wrapper<int*>>;
86 std::same_as<CommonIter> auto begin = common.begin();
87 assert(begin == std::ranges::begin(view));
88 }
89
90 return 0;
91 }
92