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 // std::views::common
12
13 #include <ranges>
14
15 #include <array>
16 #include <cassert>
17 #include <concepts>
18 #include <utility>
19
20 #include "test_iterators.h"
21 #include "test_range.h"
22 #include "types.h"
23
test()24 constexpr bool test() {
25 int buf[] = {1, 2, 3};
26
27 // views::common(r) is equivalent to views::all(r) if r is a common_range
28 {
29 {
30 CommonView view(buf, buf + 3);
31 std::same_as<CommonView> auto result = std::views::common(view);
32 assert(result.begin_ == buf);
33 assert(result.end_ == buf + 3);
34 }
35 {
36 using NotAView = std::array<int, 3>;
37 NotAView arr = {1, 2, 3};
38 std::same_as<std::ranges::ref_view<NotAView>> auto result = std::views::common(arr);
39 assert(result.begin() == arr.begin());
40 assert(result.end() == arr.end());
41 }
42 }
43
44 // Otherwise, views::common(r) is equivalent to ranges::common_view{r}
45 {
46 NonCommonView view(buf, buf + 3);
47 std::same_as<std::ranges::common_view<NonCommonView>> auto result = std::views::common(view);
48 assert(result.base().begin_ == buf);
49 assert(result.base().end_ == buf + 3);
50 }
51
52 // Test that std::views::common is a range adaptor
53 {
54 using SomeView = NonCommonView;
55
56 // Test `v | views::common`
57 {
58 SomeView view(buf, buf + 3);
59 std::same_as<std::ranges::common_view<SomeView>> auto result = view | std::views::common;
60 assert(result.base().begin_ == buf);
61 assert(result.base().end_ == buf + 3);
62 }
63
64 // Test `adaptor | views::common`
65 {
66 SomeView view(buf, buf + 3);
67 auto f = [](int i) { return i; };
68 auto const partial = std::views::transform(f) | std::views::common;
69 using Result = std::ranges::common_view<std::ranges::transform_view<SomeView, decltype(f)>>;
70 std::same_as<Result> auto result = partial(view);
71 assert(result.base().base().begin_ == buf);
72 assert(result.base().base().end_ == buf + 3);
73 }
74
75 // Test `views::common | adaptor`
76 {
77 SomeView view(buf, buf + 3);
78 auto f = [](int i) { return i; };
79 auto const partial = std::views::common | std::views::transform(f);
80 using Result = std::ranges::transform_view<std::ranges::common_view<SomeView>, decltype(f)>;
81 std::same_as<Result> auto result = partial(view);
82 assert(result.base().base().begin_ == buf);
83 assert(result.base().base().end_ == buf + 3);
84 }
85
86 // Check SFINAE friendliness
87 {
88 struct NotAView { };
89 static_assert(!std::is_invocable_v<decltype(std::views::common)>);
90 static_assert(!std::is_invocable_v<decltype(std::views::common), NotAView>);
91 static_assert( CanBePiped<SomeView&, decltype(std::views::common)>);
92 static_assert( CanBePiped<int(&)[10], decltype(std::views::common)>);
93 static_assert(!CanBePiped<int(&&)[10], decltype(std::views::common)>);
94 static_assert(!CanBePiped<NotAView, decltype(std::views::common)>);
95 }
96 }
97
98 {
99 static_assert(std::same_as<decltype(std::views::common), decltype(std::ranges::views::common)>);
100 }
101
102 return true;
103 }
104
main(int,char **)105 int main(int, char**) {
106 test();
107 static_assert(test());
108
109 return 0;
110 }
111