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 iterator& operator--();
13 // constexpr iterator operator--(int);
14 
15 #include <cassert>
16 #include <ranges>
17 
18 #include "test_macros.h"
19 #include "../types.h"
20 
21 constexpr bool test() {
22   int buffer[4][4] = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}, {13, 14, 15, 16}};
23 
24   {
25     // outer == ranges::end
26     std::ranges::join_view jv(buffer);
27     auto iter = std::next(jv.begin(), 16);
28     for (int i = 16; i != 0; --i) {
29       assert(*--iter == i);
30     }
31   }
32   {
33     // outer == ranges::end
34     std::ranges::join_view jv(buffer);
35     auto iter = std::next(jv.begin(), 13);
36     for (int i = 13; i != 0; --i) {
37       assert(*--iter == i);
38     }
39   }
40   {
41     // outer != ranges::end
42     std::ranges::join_view jv(buffer);
43     auto iter = std::next(jv.begin(), 12);
44     for (int i = 12; i != 0; --i) {
45       assert(*--iter == i);
46     }
47   }
48   {
49     // outer != ranges::end
50     std::ranges::join_view jv(buffer);
51     auto iter = std::next(jv.begin());
52     for (int i = 1; i != 0; --i) {
53       assert(*--iter == i);
54     }
55   }
56   {
57     int small[2][1] = {{1}, {2}};
58     std::ranges::join_view jv(small);
59     auto iter = std::next(jv.begin(), 2);
60     for (int i = 2; i != 0; --i) {
61       assert(*--iter == i);
62     }
63   }
64 
65   return true;
66 }
67 
68 int main(int, char**) {
69   test();
70   static_assert(test());
71 
72   return 0;
73 }
74