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 // UNSUPPORTED: libcpp-no-concepts
11 // UNSUPPORTED: gcc-10
12 // UNSUPPORTED: libcpp-has-no-incomplete-ranges
13 
14 // constexpr auto begin() requires (!simple-view<V>);
15 // constexpr auto begin() const requires range<const V>;
16 
17 #include <ranges>
18 #include <cassert>
19 
20 #include "test_macros.h"
21 #include "test_iterators.h"
22 #include "test_range.h"
23 #include "types.h"
24 
25 constexpr bool test() {
26   int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};
27 
28   // sized_range && random_access_iterator
29   {
30     std::ranges::take_view<SizedRandomAccessView> tv(SizedRandomAccessView{buffer}, 4);
31     assert(tv.begin() == begin(SizedRandomAccessView(buffer)));
32     ASSERT_SAME_TYPE(decltype(tv.begin()), RandomAccessIter);
33   }
34 
35   {
36     const std::ranges::take_view<SizedRandomAccessView> tv(SizedRandomAccessView{buffer}, 4);
37     assert(tv.begin() == begin(SizedRandomAccessView(buffer)));
38     ASSERT_SAME_TYPE(decltype(tv.begin()), RandomAccessIter);
39   }
40 
41   // sized_range && !random_access_iterator
42   {
43     std::ranges::take_view<SizedForwardView> tv(SizedForwardView{buffer}, 4);
44     assert(tv.begin() == std::counted_iterator<ForwardIter>(ForwardIter(buffer), 4));
45     ASSERT_SAME_TYPE(decltype(tv.begin()), std::counted_iterator<ForwardIter>);
46   }
47 
48   {
49     const std::ranges::take_view<SizedForwardView> tv(SizedForwardView{buffer}, 4);
50     assert(tv.begin() == std::counted_iterator<ForwardIter>(ForwardIter(buffer), 4));
51     ASSERT_SAME_TYPE(decltype(tv.begin()), std::counted_iterator<ForwardIter>);
52   }
53 
54   // !sized_range
55   {
56     std::ranges::take_view<ContiguousView> tv(ContiguousView{buffer}, 4);
57     assert(tv.begin() == std::counted_iterator<int*>(buffer, 4));
58     ASSERT_SAME_TYPE(decltype(tv.begin()), std::counted_iterator<int*>);
59   }
60 
61   {
62     const std::ranges::take_view<ContiguousView> tv(ContiguousView{buffer}, 4);
63     assert(tv.begin() == std::counted_iterator<int*>(buffer, 4));
64     ASSERT_SAME_TYPE(decltype(tv.begin()), std::counted_iterator<int*>);
65   }
66 
67   return true;
68 }
69 
70 int main(int, char**) {
71   test();
72   static_assert(test());
73 
74   return 0;
75 }
76