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 <cassert>
15 #include <ranges>
16 #include <tuple>
17 #include <utility>
18
19 #include "types.h"
20
21 template <class T>
22 concept HasSize = requires(T t) { t.size(); };
23
24 static_assert(HasSize<std::ranges::elements_view<SimpleCommon, 0>>);
25 static_assert(HasSize<const std::ranges::elements_view<SimpleCommon, 0>>);
26
27 struct NonSized : std::ranges::view_base {
28 using iterator = forward_iterator<std::tuple<int>*>;
29 iterator begin() const;
30 iterator end() const;
31 };
32 static_assert(!std::ranges::sized_range<NonSized>);
33 static_assert(!std::ranges::sized_range<const NonSized>);
34
35 static_assert(!HasSize<std::ranges::elements_view<NonSized, 0>>);
36 static_assert(!HasSize<const std::ranges::elements_view<NonSized, 0>>);
37
38 struct SizedNonConst : TupleBufferView {
39 using TupleBufferView::TupleBufferView;
40
41 using iterator = forward_iterator<std::tuple<int>*>;
beginSizedNonConst42 constexpr auto begin() const { return iterator{buffer_}; }
endSizedNonConst43 constexpr auto end() const { return iterator{buffer_ + size_}; }
sizeSizedNonConst44 constexpr std::size_t size() { return size_; }
45 };
46
47 static_assert(HasSize<std::ranges::elements_view<SizedNonConst, 0>>);
48 static_assert(!HasSize<const std::ranges::elements_view<SizedNonConst, 0>>);
49
50 struct OnlyConstSized : TupleBufferView {
51 using TupleBufferView::TupleBufferView;
52
53 using iterator = forward_iterator<std::tuple<int>*>;
beginOnlyConstSized54 constexpr auto begin() const { return iterator{buffer_}; }
endOnlyConstSized55 constexpr auto end() const { return iterator{buffer_ + size_}; }
sizeOnlyConstSized56 constexpr std::size_t size() const { return size_; }
57 constexpr std::size_t size() = delete;
58 };
59
60 static_assert(HasSize<const OnlyConstSized>);
61 static_assert(HasSize<std::ranges::elements_view<OnlyConstSized, 0>>);
62 static_assert(HasSize<const std::ranges::elements_view<OnlyConstSized, 0>>);
63
test()64 constexpr bool test() {
65 std::tuple<int> buffer[] = {{1}, {2}, {3}};
66
67 // non-const and const are sized
68 {
69 auto ev = std::views::elements<0>(buffer);
70 assert(ev.size() == 3);
71 assert(std::as_const(ev).size() == 3);
72 }
73
74 {
75 // const-view non-sized range
76 auto ev = std::views::elements<0>(SizedNonConst{buffer});
77 assert(ev.size() == 3);
78 }
79
80 return true;
81 }
82
main(int,char **)83 int main(int, char**) {
84 test();
85 static_assert(test());
86
87 return 0;
88 }
89