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-has-no-incomplete-ranges
11 
12 // constexpr auto begin();
13 // constexpr auto begin() const;
14 
15 #include <cassert>
16 #include <ranges>
17 
18 #include "test_macros.h"
19 #include "types.h"
20 
21 struct NonSimpleParentView : std::ranges::view_base {
22   ChildView* begin() { return nullptr; }
23   const ChildView* begin() const;
24   const ChildView* end() const;
25 };
26 
27 struct SimpleParentView : std::ranges::view_base {
28   const ChildView* begin() const;
29   const ChildView* end() const;
30 };
31 
32 constexpr bool test() {
33   int buffer[4][4] = {{1111, 2222, 3333, 4444}, {555, 666, 777, 888}, {99, 1010, 1111, 1212}, {13, 14, 15, 16}};
34 
35   {
36     ChildView children[4] = {ChildView(buffer[0]), ChildView(buffer[1]), ChildView(buffer[2]), ChildView(buffer[3])};
37     auto jv = std::ranges::join_view(ParentView{children});
38     assert(*jv.begin() == 1111);
39   }
40 
41   {
42     CopyableChild children[4] = {CopyableChild(buffer[0], 4), CopyableChild(buffer[1], 0), CopyableChild(buffer[2], 1), CopyableChild(buffer[3], 0)};
43     auto jv = std::ranges::join_view(ParentView{children});
44     assert(*jv.begin() == 1111);
45   }
46   // Parent is empty.
47   {
48     CopyableChild children[4] = {CopyableChild(buffer[0]), CopyableChild(buffer[1]), CopyableChild(buffer[2]), CopyableChild(buffer[3])};
49     std::ranges::join_view jv(ParentView(children, 0));
50     assert(jv.begin() == jv.end());
51   }
52   // Parent size is one.
53   {
54     CopyableChild children[1] = {CopyableChild(buffer[0])};
55     std::ranges::join_view jv(ParentView(children, 1));
56     assert(*jv.begin() == 1111);
57   }
58   // Parent and child size is one.
59   {
60     CopyableChild children[1] = {CopyableChild(buffer[0], 1)};
61     std::ranges::join_view jv(ParentView(children, 1));
62     assert(*jv.begin() == 1111);
63   }
64   // Parent size is one child is empty
65   {
66     CopyableChild children[1] = {CopyableChild(buffer[0], 0)};
67     std::ranges::join_view jv(ParentView(children, 1));
68     assert(jv.begin() == jv.end());
69   }
70   // Has all empty children.
71   {
72     CopyableChild children[4] = {CopyableChild(buffer[0], 0), CopyableChild(buffer[1], 0), CopyableChild(buffer[2], 0), CopyableChild(buffer[3], 0)};
73     auto jv = std::ranges::join_view(ParentView{children});
74     assert(jv.begin() == jv.end());
75   }
76   // First child is empty, others are not.
77   {
78     CopyableChild children[4] = {CopyableChild(buffer[0], 4), CopyableChild(buffer[1], 0), CopyableChild(buffer[2], 0), CopyableChild(buffer[3], 0)};
79     auto jv = std::ranges::join_view(ParentView{children});
80     assert(*jv.begin() == 1111);
81   }
82   // Last child is empty, others are not.
83   {
84     CopyableChild children[4] = {CopyableChild(buffer[0], 4), CopyableChild(buffer[1], 4), CopyableChild(buffer[2], 4), CopyableChild(buffer[3], 0)};
85     auto jv = std::ranges::join_view(ParentView{children});
86     assert(*jv.begin() == 1111);
87   }
88 
89   {
90     std::ranges::join_view jv(buffer);
91     assert(*jv.begin() == 1111);
92   }
93 
94   {
95     const std::ranges::join_view jv(buffer);
96     assert(*jv.begin() == 1111);
97   }
98 
99   // !simple-view<V>
100   {
101     std::ranges::join_view<NonSimpleParentView> jv;
102     static_assert(!std::same_as<decltype(jv.begin()),
103                                 decltype(std::as_const(jv).begin())>);
104   }
105 
106   // simple-view<V> && is_reference_v<range_reference_t<V>>;
107   {
108     std::ranges::join_view<SimpleParentView> jv;
109     static_assert(std::same_as<decltype(jv.begin()),
110                                decltype(std::as_const(jv).begin())>);
111   }
112 
113   return true;
114 }
115 
116 int main(int, char**) {
117   test();
118   static_assert(test());
119 
120   return 0;
121 }
122