| //===----------------------------------------------------------------------===// |
| // |
| // 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 |
| |
| // std::views::filter |
| |
| #include <ranges> |
| |
| #include <cassert> |
| #include <concepts> |
| #include <initializer_list> |
| #include <type_traits> |
| #include <utility> |
| |
| #include "test_iterators.h" |
| |
| template <class View, class T> |
| concept CanBePiped = requires (View&& view, T&& t) { |
| { std::forward<View>(view) | std::forward<T>(t) }; |
| }; |
| |
| struct NonCopyablePredicate { |
| NonCopyablePredicate(NonCopyablePredicate const&) = delete; |
| template <class T> |
| constexpr bool operator()(T x) const { return x % 2 == 0; } |
| }; |
| |
| struct Range : std::ranges::view_base { |
| using Iterator = forward_iterator<int*>; |
| using Sentinel = sentinel_wrapper<Iterator>; |
| constexpr explicit Range(int* b, int* e) : begin_(b), end_(e) { } |
| constexpr Iterator begin() const { return Iterator(begin_); } |
| constexpr Sentinel end() const { return Sentinel(Iterator(end_)); } |
| |
| private: |
| int* begin_; |
| int* end_; |
| }; |
| |
| struct Pred { |
| constexpr bool operator()(int i) const { return i % 2 == 0; } |
| }; |
| |
| template <typename View> |
| constexpr void compareViews(View v, std::initializer_list<int> list) { |
| auto b1 = v.begin(); |
| auto e1 = v.end(); |
| auto b2 = list.begin(); |
| auto e2 = list.end(); |
| for (; b1 != e1 && b2 != e2; ++b1, ++b2) { |
| assert(*b1 == *b2); |
| } |
| assert(b1 == e1); |
| assert(b2 == e2); |
| } |
| |
| constexpr bool test() { |
| int buff[] = {0, 1, 2, 3, 4, 5, 6, 7}; |
| |
| // Test `views::filter(pred)(v)` |
| { |
| using Result = std::ranges::filter_view<Range, Pred>; |
| Range const range(buff, buff + 8); |
| Pred pred; |
| |
| { |
| std::same_as<Result> decltype(auto) result = std::views::filter(pred)(range); |
| compareViews(result, {0, 2, 4, 6}); |
| } |
| { |
| auto const partial = std::views::filter(pred); |
| std::same_as<Result> decltype(auto) result = partial(range); |
| compareViews(result, {0, 2, 4, 6}); |
| } |
| } |
| |
| // Test `v | views::filter(pred)` |
| { |
| using Result = std::ranges::filter_view<Range, Pred>; |
| Range const range(buff, buff + 8); |
| Pred pred; |
| |
| { |
| std::same_as<Result> decltype(auto) result = range | std::views::filter(pred); |
| compareViews(result, {0, 2, 4, 6}); |
| } |
| { |
| auto const partial = std::views::filter(pred); |
| std::same_as<Result> decltype(auto) result = range | partial; |
| compareViews(result, {0, 2, 4, 6}); |
| } |
| } |
| |
| // Test `views::filter(v, pred)` |
| { |
| using Result = std::ranges::filter_view<Range, Pred>; |
| Range const range(buff, buff + 8); |
| Pred pred; |
| |
| std::same_as<Result> decltype(auto) result = std::views::filter(range, pred); |
| compareViews(result, {0, 2, 4, 6}); |
| } |
| |
| // Test that one can call std::views::filter with arbitrary stuff, as long as we |
| // don't try to actually complete the call by passing it a range. |
| // |
| // That makes no sense and we can't do anything with the result, but it's valid. |
| { |
| struct X { }; |
| [[maybe_unused]] auto partial = std::views::filter(X{}); |
| } |
| |
| // Test `adaptor | views::filter(pred)` |
| { |
| Range const range(buff, buff + 8); |
| |
| { |
| auto pred1 = [](int i) { return i % 2 == 0; }; |
| auto pred2 = [](int i) { return i % 3 == 0; }; |
| using Result = std::ranges::filter_view<std::ranges::filter_view<Range, decltype(pred1)>, decltype(pred2)>; |
| std::same_as<Result> decltype(auto) result = range | std::views::filter(pred1) | std::views::filter(pred2); |
| compareViews(result, {0, 6}); |
| } |
| { |
| auto pred1 = [](int i) { return i % 2 == 0; }; |
| auto pred2 = [](int i) { return i % 3 == 0; }; |
| using Result = std::ranges::filter_view<std::ranges::filter_view<Range, decltype(pred1)>, decltype(pred2)>; |
| auto const partial = std::views::filter(pred1) | std::views::filter(pred2); |
| std::same_as<Result> decltype(auto) result = range | partial; |
| compareViews(result, {0, 6}); |
| } |
| } |
| |
| // Test SFINAE friendliness |
| { |
| struct NotAView { }; |
| struct NotInvocable { }; |
| |
| static_assert(!CanBePiped<Range, decltype(std::views::filter)>); |
| static_assert( CanBePiped<Range, decltype(std::views::filter(Pred{}))>); |
| static_assert(!CanBePiped<NotAView, decltype(std::views::filter(Pred{}))>); |
| static_assert(!CanBePiped<Range, decltype(std::views::filter(NotInvocable{}))>); |
| |
| static_assert(!std::is_invocable_v<decltype(std::views::filter)>); |
| static_assert(!std::is_invocable_v<decltype(std::views::filter), Pred, Range>); |
| static_assert( std::is_invocable_v<decltype(std::views::filter), Range, Pred>); |
| static_assert(!std::is_invocable_v<decltype(std::views::filter), Range, Pred, Pred>); |
| static_assert(!std::is_invocable_v<decltype(std::views::filter), NonCopyablePredicate>); |
| } |
| |
| { |
| static_assert(std::is_same_v<decltype(std::ranges::views::filter), decltype(std::views::filter)>); |
| } |
| |
| return true; |
| } |
| |
| int main(int, char**) { |
| test(); |
| static_assert(test()); |
| |
| return 0; |
| } |