| //===----------------------------------------------------------------------===// |
| // |
| // 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 auto begin() |
| // requires (!(simple-view<V> && |
| // random_access_range<const V> && sized_range<const V>)); |
| // constexpr auto begin() const |
| // requires random_access_range<const V> && sized_range<const V>; |
| |
| #include <ranges> |
| |
| #include "test_macros.h" |
| #include "test_iterators.h" |
| #include "types.h" |
| |
| template<class T> |
| concept BeginInvocable = requires(std::ranges::drop_view<T> t) { t.begin(); }; |
| |
| template <bool IsSimple> |
| struct MaybeSimpleView : std::ranges::view_base { |
| int* num_of_non_const_begin_calls; |
| int* num_of_const_begin_calls; |
| |
| constexpr int* begin() { |
| ++(*num_of_non_const_begin_calls); |
| return nullptr; |
| } |
| constexpr std::conditional_t<IsSimple, int*, const int*> begin() const { |
| ++(*num_of_const_begin_calls); |
| return nullptr; |
| } |
| constexpr int* end() const { return nullptr; } |
| constexpr std::size_t size() const { return 0; } |
| }; |
| |
| using SimpleView = MaybeSimpleView<true>; |
| using NonSimpleView = MaybeSimpleView<false>; |
| |
| constexpr bool test() { |
| // random_access_range<const V> && sized_range<const V> |
| std::ranges::drop_view dropView1(MoveOnlyView(), 4); |
| assert(dropView1.begin() == globalBuff + 4); |
| |
| // !random_access_range<const V> |
| std::ranges::drop_view dropView2(ForwardView(), 4); |
| assert(base(dropView2.begin()) == globalBuff + 4); |
| |
| // !random_access_range<const V> |
| std::ranges::drop_view dropView3(InputView(), 4); |
| assert(base(dropView3.begin()) == globalBuff + 4); |
| |
| // random_access_range<const V> && sized_range<const V> |
| std::ranges::drop_view dropView4(MoveOnlyView(), 8); |
| assert(dropView4.begin() == globalBuff + 8); |
| |
| // random_access_range<const V> && sized_range<const V> |
| std::ranges::drop_view dropView5(MoveOnlyView(), 0); |
| assert(dropView5.begin() == globalBuff); |
| |
| // random_access_range<const V> && sized_range<const V> |
| const std::ranges::drop_view dropView6(MoveOnlyView(), 0); |
| assert(dropView6.begin() == globalBuff); |
| |
| // random_access_range<const V> && sized_range<const V> |
| std::ranges::drop_view dropView7(MoveOnlyView(), 10); |
| assert(dropView7.begin() == globalBuff + 8); |
| |
| CountedView view8; |
| std::ranges::drop_view dropView8(view8, 5); |
| assert(base(base(dropView8.begin())) == globalBuff + 5); |
| assert(dropView8.begin().stride_count() == 5); |
| assert(base(base(dropView8.begin())) == globalBuff + 5); |
| assert(dropView8.begin().stride_count() == 5); |
| |
| static_assert(!BeginInvocable<const ForwardView>); |
| |
| { |
| static_assert(std::ranges::random_access_range<const SimpleView>); |
| static_assert(std::ranges::sized_range<const SimpleView>); |
| LIBCPP_STATIC_ASSERT(std::ranges::__simple_view<SimpleView>); |
| int non_const_calls = 0; |
| int const_calls = 0; |
| std::ranges::drop_view dropView(SimpleView{{}, &non_const_calls, &const_calls}, 4); |
| assert(dropView.begin() == nullptr); |
| assert(non_const_calls == 0); |
| assert(const_calls == 1); |
| assert(std::as_const(dropView).begin() == nullptr); |
| assert(non_const_calls == 0); |
| assert(const_calls == 2); |
| } |
| |
| { |
| static_assert(std::ranges::random_access_range<const NonSimpleView>); |
| static_assert(std::ranges::sized_range<const NonSimpleView>); |
| LIBCPP_STATIC_ASSERT(!std::ranges::__simple_view<NonSimpleView>); |
| int non_const_calls = 0; |
| int const_calls = 0; |
| std::ranges::drop_view dropView(NonSimpleView{{}, &non_const_calls, &const_calls}, 4); |
| assert(dropView.begin() == nullptr); |
| assert(non_const_calls == 1); |
| assert(const_calls == 0); |
| assert(std::as_const(dropView).begin() == nullptr); |
| assert(non_const_calls == 1); |
| assert(const_calls == 1); |
| } |
| |
| return true; |
| } |
| |
| int main(int, char**) { |
| test(); |
| static_assert(test()); |
| |
| return 0; |
| } |