| //===----------------------------------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| // UNSUPPORTED: c++03, c++11, c++14, c++17 |
| // UNSUPPORTED: libcpp-no-concepts |
| |
| // constexpr counted_iterator& operator--() |
| // requires bidirectional_iterator<I>; |
| // constexpr counted_iterator operator--(int) |
| // requires bidirectional_iterator<I>; |
| |
| #include <iterator> |
| |
| #include "test_macros.h" |
| #include "test_iterators.h" |
| |
| template<class Iter> |
| concept MinusEnabled = requires(Iter& iter) { |
| iter--; |
| --iter; |
| }; |
| |
| constexpr bool test() { |
| int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8}; |
| |
| { |
| using Counted = std::counted_iterator<bidirectional_iterator<int*>>; |
| std::counted_iterator iter(bidirectional_iterator<int*>{buffer + 2}, 6); |
| assert(iter-- == Counted(bidirectional_iterator<int*>{buffer + 2}, 6)); |
| assert(--iter == Counted(bidirectional_iterator<int*>{buffer}, 8)); |
| assert(iter.count() == 8); |
| |
| ASSERT_SAME_TYPE(decltype(iter--), Counted); |
| ASSERT_SAME_TYPE(decltype(--iter), Counted&); |
| } |
| { |
| using Counted = std::counted_iterator<random_access_iterator<int*>>; |
| Counted iter(random_access_iterator<int*>{buffer + 2}, 6); |
| assert(iter-- == Counted(random_access_iterator<int*>{buffer + 2}, 6)); |
| assert(--iter == Counted(random_access_iterator<int*>{buffer}, 8)); |
| assert(iter.count() == 8); |
| |
| ASSERT_SAME_TYPE(decltype(iter--), Counted); |
| ASSERT_SAME_TYPE(decltype(--iter), Counted&); |
| } |
| { |
| using Counted = std::counted_iterator<contiguous_iterator<int*>>; |
| std::counted_iterator iter(contiguous_iterator<int*>{buffer + 2}, 6); |
| assert(iter-- == Counted(contiguous_iterator<int*>{buffer + 2}, 6)); |
| assert(--iter == Counted(contiguous_iterator<int*>{buffer}, 8)); |
| assert(iter.count() == 8); |
| |
| ASSERT_SAME_TYPE(decltype(iter--), Counted); |
| ASSERT_SAME_TYPE(decltype(--iter), Counted&); |
| } |
| |
| { |
| static_assert( MinusEnabled<std::counted_iterator<contiguous_iterator<int*>>>); |
| static_assert(!MinusEnabled<const std::counted_iterator<contiguous_iterator<int*>>>); |
| static_assert(!MinusEnabled<std::counted_iterator<forward_iterator<int*>>>); |
| } |
| |
| return true; |
| } |
| |
| int main(int, char**) { |
| test(); |
| static_assert(test()); |
| |
| return 0; |
| } |