xref: /llvm-project/libcxx/test/std/ranges/range.adaptors/range.take/size.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 auto size() requires sized_range<V>
12 // constexpr auto size() const requires sized_range<const V>
13 
14 #include <ranges>
15 #include <cassert>
16 
17 #include "test_macros.h"
18 #include "test_iterators.h"
19 #include "test_range.h"
20 #include "types.h"
21 
22 template<class T>
23 concept SizeEnabled = requires(const std::ranges::take_view<T>& tv) {
24   tv.size();
25 };
26 
test()27 constexpr bool test() {
28   int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};
29 
30   {
31     static_assert( SizeEnabled<SizedRandomAccessView>);
32     static_assert(!SizeEnabled<CopyableView>);
33   }
34 
35   {
36     std::ranges::take_view<SizedRandomAccessView> tv(SizedRandomAccessView{buffer}, 0);
37     assert(tv.size() == 0);
38   }
39 
40   {
41     const std::ranges::take_view<SizedRandomAccessView> tv(SizedRandomAccessView{buffer}, 2);
42     assert(tv.size() == 2);
43   }
44 
45   {
46     std::ranges::take_view<SizedForwardView> tv(SizedForwardView{buffer}, 4);
47     assert(tv.size() == 4);
48   }
49 
50   {
51     const std::ranges::take_view<SizedForwardView> tv(SizedForwardView{buffer}, 6);
52     assert(tv.size() == 6);
53   }
54 
55   {
56     std::ranges::take_view<SizedForwardView> tv(SizedForwardView{buffer}, 8);
57     assert(tv.size() == 8);
58   }
59   {
60     const std::ranges::take_view<SizedForwardView> tv(SizedForwardView{buffer}, 8);
61     assert(tv.size() == 8);
62   }
63 
64   {
65     std::ranges::take_view<SizedForwardView> tv(SizedForwardView{buffer}, 10);
66     assert(tv.size() == 8);
67   }
68   {
69     const std::ranges::take_view<SizedForwardView> tv(SizedForwardView{buffer}, 10);
70     assert(tv.size() == 8);
71   }
72 
73   return true;
74 }
75 
main(int,char **)76 int main(int, char**) {
77   test();
78   static_assert(test());
79 
80   return 0;
81 }
82