xref: /llvm-project/libcxx/test/std/ranges/range.adaptors/range.common.view/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_iterators.h"
18 #include "types.h"
19 
20 template<class View>
21 concept SizeEnabled = requires(View v) { v.size(); };
22 
test()23 constexpr bool test() {
24   int buf[8] = {1, 2, 3, 4, 5, 6, 7, 8};
25 
26   {
27     static_assert( SizeEnabled<std::ranges::common_view<SizedForwardView> const&>);
28     static_assert(!SizeEnabled<std::ranges::common_view<CopyableView> const&>);
29   }
30 
31   {
32     SizedForwardView view{buf, buf + 8};
33     std::ranges::common_view<SizedForwardView> common(view);
34     assert(common.size() == 8);
35   }
36 
37   {
38     SizedForwardView view{buf, buf + 8};
39     std::ranges::common_view<SizedForwardView> const common(view);
40     assert(common.size() == 8);
41   }
42 
43   return true;
44 }
45 
main(int,char **)46 int main(int, char**) {
47   test();
48   static_assert(test());
49 
50   return 0;
51 }
52