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::lazy_split
12
13 #include <ranges>
14
15 #include <array>
16 #include <cassert>
17 #include <concepts>
18 #include <string_view>
19 #include <utility>
20
21 #include "test_iterators.h"
22 #include "test_range.h"
23 #include "types.h"
24
25 struct SomeView : std::ranges::view_base {
26 const std::string_view* v_;
SomeViewSomeView27 constexpr SomeView(const std::string_view& v) : v_(&v) {}
beginSomeView28 constexpr auto begin() const { return v_->begin(); }
endSomeView29 constexpr auto end() const { return v_->end(); }
30 };
31
32 struct NotAView { };
33
34 static_assert(!std::is_invocable_v<decltype(std::views::lazy_split)>);
35 static_assert(!std::is_invocable_v<decltype(std::views::lazy_split), SomeView, NotAView>);
36 static_assert(!std::is_invocable_v<decltype(std::views::lazy_split), NotAView, SomeView>);
37 static_assert( std::is_invocable_v<decltype(std::views::lazy_split), SomeView, SomeView>);
38
39 // Regression test for #75002, views::lazy_split shouldn't be a range adaptor closure
40 static_assert(!CanBePiped<SomeView&, decltype(std::views::lazy_split)>);
41 static_assert(!CanBePiped<char (&)[10], decltype(std::views::lazy_split)>);
42 static_assert(!CanBePiped<char (&&)[10], decltype(std::views::lazy_split)>);
43 static_assert(!CanBePiped<NotAView, decltype(std::views::lazy_split)>);
44
45 static_assert(CanBePiped<SomeView&, decltype(std::views::lazy_split('x'))>);
46 static_assert(CanBePiped<char (&)[10], decltype(std::views::lazy_split('x'))>);
47 static_assert(!CanBePiped<char (&&)[10], decltype(std::views::lazy_split('x'))>);
48 static_assert(!CanBePiped<NotAView, decltype(std::views::lazy_split('x'))>);
49
50 static_assert(std::same_as<decltype(std::views::lazy_split), decltype(std::ranges::views::lazy_split)>);
51
test()52 constexpr bool test() {
53 std::string_view input = "abc";
54 std::string_view sep = "a";
55
56 // Test that `std::views::lazy_split` is a range adaptor.
57
58 // Test `views::lazy_split(input, sep)`.
59 {
60 SomeView view(input);
61
62 using Result = std::ranges::lazy_split_view<SomeView, std::string_view>;
63 std::same_as<Result> decltype(auto) result = std::views::lazy_split(view, sep);
64 assert(result.base().begin() == input.begin());
65 assert(result.base().end() == input.end());
66 }
67
68 // Test `views::lazy_split(sep)(input)`.
69 {
70 SomeView view(input);
71
72 using Result = std::ranges::lazy_split_view<SomeView, std::string_view>;
73 std::same_as<Result> decltype(auto) result = std::views::lazy_split(sep)(view);
74 assert(result.base().begin() == input.begin());
75 assert(result.base().end() == input.end());
76 }
77
78 // Test `view | views::lazy_split`.
79 {
80 SomeView view(input);
81
82 using Result = std::ranges::lazy_split_view<SomeView, std::string_view>;
83 std::same_as<Result> decltype(auto) result = view | std::views::lazy_split(sep);
84 assert(result.base().begin() == input.begin());
85 assert(result.base().end() == input.end());
86 }
87
88 // Test `adaptor | views::lazy_split`.
89 {
90 SomeView view(input);
91 auto f = [](char c) { return c; };
92 auto partial = std::views::transform(f) | std::views::lazy_split(sep);
93
94 using Result = std::ranges::lazy_split_view<std::ranges::transform_view<SomeView, decltype(f)>, std::string_view>;
95 std::same_as<Result> decltype(auto) result = partial(view);
96 assert(result.base().base().begin() == input.begin());
97 assert(result.base().base().end() == input.end());
98 }
99
100 // Test `views::lazy_split | adaptor`.
101 {
102 SomeView view(input);
103 auto f = [](auto v) { return v; };
104 auto partial = std::views::lazy_split(sep) | std::views::transform(f);
105
106 using Result = std::ranges::transform_view<std::ranges::lazy_split_view<SomeView, std::string_view>, decltype(f)>;
107 std::same_as<Result> decltype(auto) result = partial(view);
108 assert(result.base().base().begin() == input.begin());
109 assert(result.base().base().end() == input.end());
110 }
111
112 // Test that one can call `std::views::lazy_split` with arbitrary stuff, as long as we
113 // don't try to actually complete the call by passing it a range.
114 //
115 // That makes no sense and we can't do anything with the result, but it's valid.
116 {
117 struct X { };
118 [[maybe_unused]] auto partial = std::views::lazy_split(X{});
119 }
120
121 return true;
122 }
123
main(int,char **)124 int main(int, char**) {
125 test();
126 static_assert(test());
127
128 return 0;
129 }
130