1 // Copyright (C) 2019-2021 Free Software Foundation, Inc.
3 // This file is part of the GNU ISO C++ Library. This library is free
4 // software; you can redistribute it and/or modify it under the
5 // terms of the GNU General Public License as published by the
6 // Free Software Foundation; either version 3, or (at your option)
9 // This library is distributed in the hope that it will be useful,
10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 // GNU General Public License for more details.
14 // You should have received a copy of the GNU General Public License along
15 // with this library; see the file COPYING3. If not see
16 // <http://www.gnu.org/licenses/>.
18 // { dg-options "-std=gnu++2a" }
19 // { dg-do run { target c++2a } }
22 #include <testsuite_hooks.h>
23 #include <testsuite_iterators.h>
25 using __gnu_test::test_range
;
26 using __gnu_test::random_access_iterator_wrapper
;
27 using __gnu_test::bidirectional_iterator_wrapper
;
28 using __gnu_test::forward_iterator_wrapper
;
29 using __gnu_test::input_iterator_wrapper
;
30 using __gnu_test::output_iterator_wrapper
;
35 int a
[10] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
36 test_range
<int, random_access_iterator_wrapper
> r(a
);
37 auto begin
= r
.begin();
39 auto endi
= std::ranges::next(begin
, end
);
40 VERIFY( *std::ranges::prev(endi
) == 9 );
41 VERIFY( std::ranges::prev(begin
, 0) == begin
);
42 VERIFY( *std::ranges::prev(endi
, 1) == 9 );
43 VERIFY( *std::ranges::prev(endi
, 3) == 7 );
44 VERIFY( *std::ranges::prev(begin
, -4) == 4 );
45 VERIFY( std::ranges::prev(begin
, 0, begin
) == begin
);
46 VERIFY( std::ranges::prev(begin
, 5, begin
) == begin
);
47 VERIFY( std::ranges::prev(begin
, -5, begin
) == begin
);
48 VERIFY( std::ranges::prev(begin
, 0, endi
) == begin
);
49 VERIFY( *std::ranges::prev(endi
, 5, begin
) == 5 );
50 VERIFY( std::ranges::prev(endi
, 55, begin
) == begin
);
51 VERIFY( std::ranges::prev(endi
, 0, endi
) == end
);
52 VERIFY( std::ranges::prev(endi
, -5, endi
) == end
);
53 VERIFY( std::ranges::prev(endi
, -55, endi
) == end
);
54 VERIFY( std::ranges::prev(endi
, 0, begin
) == end
);
55 VERIFY( *std::ranges::prev(begin
, -5, endi
) == 5 );
56 VERIFY( std::ranges::prev(begin
, -55, endi
) == end
);
62 int a
[10] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
63 test_range
<int, bidirectional_iterator_wrapper
> r(a
);
64 auto begin
= r
.begin();
66 auto endi
= std::ranges::next(begin
, end
);
67 VERIFY( *std::ranges::prev(endi
) == 9 );
68 VERIFY( std::ranges::prev(begin
, 0) == begin
);
69 VERIFY( *std::ranges::prev(endi
, 1) == 9 );
70 VERIFY( *std::ranges::prev(endi
, 3) == 7 );
71 VERIFY( *std::ranges::prev(begin
, -4) == 4 );
72 VERIFY( std::ranges::prev(begin
, 0, begin
) == begin
);
73 VERIFY( std::ranges::prev(begin
, 5, begin
) == begin
);
74 VERIFY( std::ranges::prev(begin
, -5, begin
) == begin
);
75 VERIFY( std::ranges::prev(begin
, 0, endi
) == begin
);
76 VERIFY( *std::ranges::prev(endi
, 5, begin
) == 5 );
77 VERIFY( std::ranges::prev(endi
, 55, begin
) == begin
);
78 VERIFY( std::ranges::prev(endi
, 0, endi
) == end
);
79 VERIFY( std::ranges::prev(endi
, -5, endi
) == end
);
80 VERIFY( std::ranges::prev(endi
, -55, endi
) == end
);
81 VERIFY( std::ranges::prev(endi
, 0, begin
) == end
);
82 VERIFY( *std::ranges::prev(begin
, -5, endi
) == 5 );
83 VERIFY( std::ranges::prev(begin
, -55, endi
) == end
);
87 concept can_prev
= requires(T
& t
) { std::ranges::prev(t
); }
88 || requires(T
& t
) { std::ranges::prev(t
, 1); }
89 || requires(T
& t
) { std::ranges::prev(t
, 1, t
); };
91 static_assert( !can_prev
<forward_iterator_wrapper
<int>> );
92 static_assert( !can_prev
<input_iterator_wrapper
<int>> );
93 static_assert( !can_prev
<output_iterator_wrapper
<int>> );