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 size() requires sized_range<V>
15 // constexpr auto size() const requires sized_range<const V>
16 
17 #include <ranges>
18 #include <cassert>
19 
20 #include "test_iterators.h"
21 #include "test_range.h"
22 
23 struct CopyableView : std::ranges::view_base {
24   int *ptr_;
25   constexpr CopyableView(int* ptr) : ptr_(ptr) {}
26   friend constexpr int* begin(CopyableView& view) { return view.ptr_; }
27   friend constexpr int* begin(CopyableView const& view) { return view.ptr_; }
28   friend constexpr sentinel_wrapper<int*> end(CopyableView& view) {
29     return sentinel_wrapper<int*>{view.ptr_ + 8};
30   }
31   friend constexpr sentinel_wrapper<int*> end(CopyableView const& view) {
32     return sentinel_wrapper<int*>{view.ptr_ + 8};
33   }
34 };
35 
36 using ForwardIter = forward_iterator<int*>;
37 struct SizedForwardView : std::ranges::view_base {
38   int *ptr_;
39   constexpr SizedForwardView(int* ptr) : ptr_(ptr) {}
40   friend constexpr ForwardIter begin(SizedForwardView& view) { return ForwardIter(view.ptr_); }
41   friend constexpr ForwardIter begin(SizedForwardView const& view) { return ForwardIter(view.ptr_); }
42   friend constexpr sentinel_wrapper<ForwardIter> end(SizedForwardView& view) {
43     return sentinel_wrapper<ForwardIter>{ForwardIter(view.ptr_ + 8)};
44   }
45   friend constexpr sentinel_wrapper<ForwardIter> end(SizedForwardView const& view) {
46     return sentinel_wrapper<ForwardIter>{ForwardIter(view.ptr_ + 8)};
47   }
48 };
49 
50 constexpr auto operator-(sentinel_wrapper<ForwardIter> sent, ForwardIter iter) {
51   return sent.base().base() - iter.base();
52 }
53 constexpr auto operator-(ForwardIter iter, sentinel_wrapper<ForwardIter> sent) {
54   return iter.base() - sent.base().base();
55 }
56 
57 template<class T>
58 concept SizeEnabled = requires(const std::ranges::common_view<T>& comm) {
59   comm.size();
60 };
61 
62 constexpr bool test() {
63   int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};
64 
65   {
66     static_assert( SizeEnabled<SizedForwardView>);
67     static_assert(!SizeEnabled<CopyableView>);
68   }
69 
70   {
71     std::ranges::common_view<SizedForwardView> common(SizedForwardView{buffer});
72     assert(common.size() == 8);
73   }
74 
75   {
76     const std::ranges::common_view<SizedForwardView> common(SizedForwardView{buffer});
77     assert(common.size() == 8);
78   }
79 
80   return true;
81 }
82 
83 int main(int, char**) {
84   test();
85   static_assert(test());
86 
87   return 0;
88 }
89