| // Copyright (C) 2019-2021 Free Software Foundation, Inc. |
| // |
| // This file is part of the GNU ISO C++ Library. This library is free |
| // software; you can redistribute it and/or modify it under the |
| // terms of the GNU General Public License as published by the |
| // Free Software Foundation; either version 3, or (at your option) |
| // any later version. |
| |
| // This library is distributed in the hope that it will be useful, |
| // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| // GNU General Public License for more details. |
| |
| // You should have received a copy of the GNU General Public License along |
| // with this library; see the file COPYING3. If not see |
| // <http://www.gnu.org/licenses/>. |
| |
| // { dg-options "-std=gnu++2a" } |
| // { dg-do run { target c++2a } } |
| |
| #include <iterator> |
| #include <testsuite_hooks.h> |
| #include <testsuite_iterators.h> |
| |
| using __gnu_test::test_range; |
| using __gnu_test::random_access_iterator_wrapper; |
| using __gnu_test::bidirectional_iterator_wrapper; |
| using __gnu_test::forward_iterator_wrapper; |
| using __gnu_test::input_iterator_wrapper; |
| using __gnu_test::output_iterator_wrapper; |
| |
| void |
| test01() |
| { |
| int a[10] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 }; |
| test_range<int, random_access_iterator_wrapper> r(a); |
| auto begin = r.begin(); |
| auto end = r.end(); |
| auto endi = std::ranges::next(begin, end); |
| VERIFY( *std::ranges::prev(endi) == 9 ); |
| VERIFY( std::ranges::prev(begin, 0) == begin ); |
| VERIFY( *std::ranges::prev(endi, 1) == 9 ); |
| VERIFY( *std::ranges::prev(endi, 3) == 7 ); |
| VERIFY( *std::ranges::prev(begin, -4) == 4 ); |
| VERIFY( std::ranges::prev(begin, 0, begin) == begin ); |
| VERIFY( std::ranges::prev(begin, 5, begin) == begin ); |
| VERIFY( std::ranges::prev(begin, -5, begin) == begin ); |
| VERIFY( std::ranges::prev(begin, 0, endi) == begin ); |
| VERIFY( *std::ranges::prev(endi, 5, begin) == 5 ); |
| VERIFY( std::ranges::prev(endi, 55, begin) == begin ); |
| VERIFY( std::ranges::prev(endi, 0, endi) == end ); |
| VERIFY( std::ranges::prev(endi, -5, endi) == end ); |
| VERIFY( std::ranges::prev(endi, -55, endi) == end ); |
| VERIFY( std::ranges::prev(endi, 0, begin) == end ); |
| VERIFY( *std::ranges::prev(begin, -5, endi) == 5 ); |
| VERIFY( std::ranges::prev(begin, -55, endi) == end ); |
| } |
| |
| void |
| test02() |
| { |
| int a[10] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 }; |
| test_range<int, bidirectional_iterator_wrapper> r(a); |
| auto begin = r.begin(); |
| auto end = r.end(); |
| auto endi = std::ranges::next(begin, end); |
| VERIFY( *std::ranges::prev(endi) == 9 ); |
| VERIFY( std::ranges::prev(begin, 0) == begin ); |
| VERIFY( *std::ranges::prev(endi, 1) == 9 ); |
| VERIFY( *std::ranges::prev(endi, 3) == 7 ); |
| VERIFY( *std::ranges::prev(begin, -4) == 4 ); |
| VERIFY( std::ranges::prev(begin, 0, begin) == begin ); |
| VERIFY( std::ranges::prev(begin, 5, begin) == begin ); |
| VERIFY( std::ranges::prev(begin, -5, begin) == begin ); |
| VERIFY( std::ranges::prev(begin, 0, endi) == begin ); |
| VERIFY( *std::ranges::prev(endi, 5, begin) == 5 ); |
| VERIFY( std::ranges::prev(endi, 55, begin) == begin ); |
| VERIFY( std::ranges::prev(endi, 0, endi) == end ); |
| VERIFY( std::ranges::prev(endi, -5, endi) == end ); |
| VERIFY( std::ranges::prev(endi, -55, endi) == end ); |
| VERIFY( std::ranges::prev(endi, 0, begin) == end ); |
| VERIFY( *std::ranges::prev(begin, -5, endi) == 5 ); |
| VERIFY( std::ranges::prev(begin, -55, endi) == end ); |
| } |
| |
| template<typename T> |
| concept can_prev = requires(T& t) { std::ranges::prev(t); } |
| || requires(T& t) { std::ranges::prev(t, 1); } |
| || requires(T& t) { std::ranges::prev(t, 1, t); }; |
| |
| static_assert( !can_prev<forward_iterator_wrapper<int>> ); |
| static_assert( !can_prev<input_iterator_wrapper<int>> ); |
| static_assert( !can_prev<output_iterator_wrapper<int>> ); |
| |
| int |
| main() |
| { |
| test01(); |
| test02(); |
| } |