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: libcpp-has-no-incomplete-ranges
12 
13 // constexpr auto begin();
14 // constexpr auto begin() const;
15 
16 #include <cassert>
17 #include <ranges>
18 
19 #include "test_macros.h"
20 #include "types.h"
21 
22 struct NonSimpleParentView : std::ranges::view_base {
23   ChildView* begin() { return nullptr; }
24   const ChildView* begin() const;
25   const ChildView* end() const;
26 };
27 
28 struct SimpleParentView : std::ranges::view_base {
29   const ChildView* begin() const;
30   const ChildView* end() const;
31 };
32 
33 constexpr bool test() {
34   int buffer[4][4] = {{1111, 2222, 3333, 4444}, {555, 666, 777, 888}, {99, 1010, 1111, 1212}, {13, 14, 15, 16}};
35 
36   {
37     ChildView children[4] = {ChildView(buffer[0]), ChildView(buffer[1]), ChildView(buffer[2]), ChildView(buffer[3])};
38     auto jv = std::ranges::join_view(ParentView{children});
39     assert(*jv.begin() == 1111);
40   }
41 
42   {
43     CopyableChild children[4] = {CopyableChild(buffer[0], 4), CopyableChild(buffer[1], 0), CopyableChild(buffer[2], 1), CopyableChild(buffer[3], 0)};
44     auto jv = std::ranges::join_view(ParentView{children});
45     assert(*jv.begin() == 1111);
46   }
47   // Parent is empty.
48   {
49     CopyableChild children[4] = {CopyableChild(buffer[0]), CopyableChild(buffer[1]), CopyableChild(buffer[2]), CopyableChild(buffer[3])};
50     std::ranges::join_view jv(ParentView(children, 0));
51     assert(jv.begin() == jv.end());
52   }
53   // Parent size is one.
54   {
55     CopyableChild children[1] = {CopyableChild(buffer[0])};
56     std::ranges::join_view jv(ParentView(children, 1));
57     assert(*jv.begin() == 1111);
58   }
59   // Parent and child size is one.
60   {
61     CopyableChild children[1] = {CopyableChild(buffer[0], 1)};
62     std::ranges::join_view jv(ParentView(children, 1));
63     assert(*jv.begin() == 1111);
64   }
65   // Parent size is one child is empty
66   {
67     CopyableChild children[1] = {CopyableChild(buffer[0], 0)};
68     std::ranges::join_view jv(ParentView(children, 1));
69     assert(jv.begin() == jv.end());
70   }
71   // Has all empty children.
72   {
73     CopyableChild children[4] = {CopyableChild(buffer[0], 0), CopyableChild(buffer[1], 0), CopyableChild(buffer[2], 0), CopyableChild(buffer[3], 0)};
74     auto jv = std::ranges::join_view(ParentView{children});
75     assert(jv.begin() == jv.end());
76   }
77   // First child is empty, others are not.
78   {
79     CopyableChild children[4] = {CopyableChild(buffer[0], 4), CopyableChild(buffer[1], 0), CopyableChild(buffer[2], 0), CopyableChild(buffer[3], 0)};
80     auto jv = std::ranges::join_view(ParentView{children});
81     assert(*jv.begin() == 1111);
82   }
83   // Last child is empty, others are not.
84   {
85     CopyableChild children[4] = {CopyableChild(buffer[0], 4), CopyableChild(buffer[1], 4), CopyableChild(buffer[2], 4), CopyableChild(buffer[3], 0)};
86     auto jv = std::ranges::join_view(ParentView{children});
87     assert(*jv.begin() == 1111);
88   }
89 
90   {
91     std::ranges::join_view jv(buffer);
92     assert(*jv.begin() == 1111);
93   }
94 
95   {
96     const std::ranges::join_view jv(buffer);
97     assert(*jv.begin() == 1111);
98   }
99 
100   // !simple-view<V>
101   {
102     std::ranges::join_view<NonSimpleParentView> jv;
103     static_assert(!std::same_as<decltype(jv.begin()),
104                                 decltype(std::as_const(jv).begin())>);
105   }
106 
107   // simple-view<V> && is_reference_v<range_reference_t<V>>;
108   {
109     std::ranges::join_view<SimpleParentView> jv;
110     static_assert(std::same_as<decltype(jv.begin()),
111                                decltype(std::as_const(jv).begin())>);
112   }
113 
114   return true;
115 }
116 
117 int main(int, char**) {
118   test();
119   static_assert(test());
120 
121   return 0;
122 }
123