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 iterator& operator--();
14 // constexpr iterator operator--(int);
15 
16 #include <cassert>
17 #include <ranges>
18 
19 #include "test_macros.h"
20 #include "../types.h"
21 
22 constexpr bool test() {
23   int buffer[4][4] = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}, {13, 14, 15, 16}};
24 
25   {
26     // outer == ranges::end
27     std::ranges::join_view jv(buffer);
28     auto iter = std::next(jv.begin(), 16);
29     for (int i = 16; i != 0; --i) {
30       assert(*--iter == i);
31     }
32   }
33   {
34     // outer == ranges::end
35     std::ranges::join_view jv(buffer);
36     auto iter = std::next(jv.begin(), 13);
37     for (int i = 13; i != 0; --i) {
38       assert(*--iter == i);
39     }
40   }
41   {
42     // outer != ranges::end
43     std::ranges::join_view jv(buffer);
44     auto iter = std::next(jv.begin(), 12);
45     for (int i = 12; i != 0; --i) {
46       assert(*--iter == i);
47     }
48   }
49   {
50     // outer != ranges::end
51     std::ranges::join_view jv(buffer);
52     auto iter = std::next(jv.begin());
53     for (int i = 1; i != 0; --i) {
54       assert(*--iter == i);
55     }
56   }
57   {
58     int small[2][1] = {{1}, {2}};
59     std::ranges::join_view jv(small);
60     auto iter = std::next(jv.begin(), 2);
61     for (int i = 2; i != 0; --i) {
62       assert(*--iter == i);
63     }
64   }
65 
66   return true;
67 }
68 
69 int main(int, char**) {
70   test();
71   static_assert(test());
72 
73   return 0;
74 }
75