| //===----------------------------------------------------------------------===// |
| // |
| // 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 |
| |
| // constexpr iterator& operator--() requires bidirectional_range<V>; |
| // constexpr iterator operator--(int) requires bidirectional_range<V>; |
| |
| #include <ranges> |
| |
| #include <array> |
| #include <cassert> |
| #include <concepts> |
| #include <iterator> |
| #include <utility> |
| #include "test_iterators.h" |
| #include "test_macros.h" |
| #include "../types.h" |
| |
| struct EqualTo { |
| int x; |
| constexpr bool operator()(int y) const { return x == y; } |
| }; |
| |
| template <class T> |
| concept has_pre_decrement = requires (T t) { { --t }; }; |
| |
| template <class T> |
| concept has_post_decrement = requires (T t) { { t-- }; }; |
| |
| template <class Iterator> |
| using FilterIteratorFor = std::ranges::iterator_t< |
| std::ranges::filter_view<minimal_view<Iterator, sentinel_wrapper<Iterator>>, EqualTo> |
| >; |
| |
| template <class Iterator, class Sentinel = sentinel_wrapper<Iterator>> |
| constexpr void test() { |
| using View = minimal_view<Iterator, Sentinel>; |
| using FilterView = std::ranges::filter_view<View, EqualTo>; |
| using FilterIterator = std::ranges::iterator_t<FilterView>; |
| |
| auto make_filter_view = [](auto begin, auto end, auto pred) { |
| View view{Iterator(begin), Sentinel(Iterator(end))}; |
| return FilterView(std::move(view), pred); |
| }; |
| |
| // Test with a single satisfied value |
| { |
| std::array<int, 5> array{0, 1, 2, 3, 4}; |
| FilterView view = make_filter_view(array.data(), array.data() + array.size(), EqualTo{1}); |
| FilterIterator it = std::ranges::next(view.begin(), view.end()); |
| assert(base(it.base()) == array.data() + array.size()); // test the test |
| |
| FilterIterator& result = --it; |
| ASSERT_SAME_TYPE(FilterIterator&, decltype(--it)); |
| assert(&result == &it); |
| assert(base(result.base()) == array.data() + 1); |
| } |
| |
| // Test with more than one satisfied value |
| { |
| std::array<int, 6> array{0, 1, 2, 3, 1, 4}; |
| FilterView view = make_filter_view(array.data(), array.data() + array.size(), EqualTo{1}); |
| FilterIterator it = std::ranges::next(view.begin(), view.end()); |
| assert(base(it.base()) == array.data() + array.size()); // test the test |
| |
| FilterIterator& result = --it; |
| assert(&result == &it); |
| assert(base(result.base()) == array.data() + 4); |
| |
| --it; |
| assert(base(it.base()) == array.data() + 1); |
| } |
| |
| // Test going forward and then backward on the same iterator |
| { |
| std::array<int, 10> array{0, 1, 2, 3, 1, 1, 4, 5, 1, 6}; |
| FilterView view = make_filter_view(array.data(), array.data() + array.size(), EqualTo{1}); |
| FilterIterator it = view.begin(); |
| ++it; |
| --it; assert(base(it.base()) == array.data() + 1); |
| ++it; ++it; |
| --it; assert(base(it.base()) == array.data() + 4); |
| ++it; ++it; |
| --it; assert(base(it.base()) == array.data() + 5); |
| ++it; ++it; |
| --it; assert(base(it.base()) == array.data() + 8); |
| } |
| |
| // Test post-decrement |
| { |
| std::array<int, 6> array{0, 1, 2, 3, 1, 4}; |
| FilterView view = make_filter_view(array.data(), array.data() + array.size(), EqualTo{1}); |
| FilterIterator it = std::ranges::next(view.begin(), view.end()); |
| assert(base(it.base()) == array.data() + array.size()); // test the test |
| |
| FilterIterator result = it--; |
| ASSERT_SAME_TYPE(FilterIterator, decltype(it--)); |
| assert(base(result.base()) == array.data() + array.size()); |
| assert(base(it.base()) == array.data() + 4); |
| |
| result = it--; |
| assert(base(result.base()) == array.data() + 4); |
| assert(base(it.base()) == array.data() + 1); |
| } |
| } |
| |
| constexpr bool tests() { |
| test<bidirectional_iterator<int*>>(); |
| test<random_access_iterator<int*>>(); |
| test<contiguous_iterator<int*>>(); |
| test<int*>(); |
| |
| test<bidirectional_iterator<int const*>>(); |
| test<random_access_iterator<int const*>>(); |
| test<contiguous_iterator<int const*>>(); |
| test<int const*>(); |
| |
| // Make sure `operator--` isn't provided for non bidirectional ranges |
| { |
| static_assert(!has_pre_decrement<FilterIteratorFor<cpp17_input_iterator<int*>>>); |
| static_assert(!has_pre_decrement<FilterIteratorFor<cpp20_input_iterator<int*>>>); |
| static_assert(!has_pre_decrement<FilterIteratorFor<forward_iterator<int*>>>); |
| |
| static_assert(!has_post_decrement<FilterIteratorFor<cpp17_input_iterator<int*>>>); |
| static_assert(!has_post_decrement<FilterIteratorFor<cpp20_input_iterator<int*>>>); |
| static_assert(!has_post_decrement<FilterIteratorFor<forward_iterator<int*>>>); |
| } |
| |
| return true; |
| } |
| |
| int main(int, char**) { |
| tests(); |
| static_assert(tests()); |
| return 0; |
| } |