xref: /llvm-project/libcxx/test/std/ranges/range.factories/range.single.view/begin.pass.cpp (revision b8cb1dc9ea87faa8e8e9ab7a31710a8c0bb8b084)
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 T* begin() noexcept;
12 // constexpr const T* begin() const noexcept;
13 
14 #include <ranges>
15 #include <cassert>
16 
17 #include "test_macros.h"
18 
19 struct Empty {};
20 struct BigType { char buffer[64] = {10}; };
21 
test()22 constexpr bool test() {
23   {
24     auto sv = std::ranges::single_view<int>(42);
25     assert(*sv.begin() == 42);
26 
27     ASSERT_SAME_TYPE(decltype(sv.begin()), int*);
28     static_assert(noexcept(sv.begin()));
29   }
30   {
31     const auto sv = std::ranges::single_view<int>(42);
32     assert(*sv.begin() == 42);
33 
34     ASSERT_SAME_TYPE(decltype(sv.begin()), const int*);
35     static_assert(noexcept(sv.begin()));
36   }
37 
38   {
39     auto sv = std::ranges::single_view<Empty>(Empty());
40     assert(sv.begin() != nullptr);
41 
42     ASSERT_SAME_TYPE(decltype(sv.begin()), Empty*);
43   }
44   {
45     const auto sv = std::ranges::single_view<Empty>(Empty());
46     assert(sv.begin() != nullptr);
47 
48     ASSERT_SAME_TYPE(decltype(sv.begin()), const Empty*);
49   }
50 
51   {
52     auto sv = std::ranges::single_view<BigType>(BigType());
53     assert(sv.begin()->buffer[0] == 10);
54 
55     ASSERT_SAME_TYPE(decltype(sv.begin()), BigType*);
56   }
57   {
58     const auto sv = std::ranges::single_view<BigType>(BigType());
59     assert(sv.begin()->buffer[0] == 10);
60 
61     ASSERT_SAME_TYPE(decltype(sv.begin()), const BigType*);
62   }
63 
64   return true;
65 }
66 
main(int,char **)67 int main(int, char**) {
68   test();
69   static_assert(test());
70 
71   return 0;
72 }
73