| //===----------------------------------------------------------------------===// |
| // |
| // 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 reverse_iterator<iterator_t<V>> begin(); |
| // constexpr reverse_iterator<iterator_t<V>> begin() requires common_range<V>; |
| // constexpr auto begin() const requires common_range<const V>; |
| |
| #include <ranges> |
| #include <cassert> |
| |
| #include "test_macros.h" |
| #include "types.h" |
| |
| static int globalCount = 0; |
| |
| struct CountedIter { |
| typedef std::bidirectional_iterator_tag iterator_category; |
| typedef int value_type; |
| typedef std::ptrdiff_t difference_type; |
| typedef int* pointer; |
| typedef int& reference; |
| typedef CountedIter self; |
| |
| pointer ptr_; |
| CountedIter(pointer ptr) : ptr_(ptr) {} |
| CountedIter() = default; |
| |
| reference operator*() const; |
| pointer operator->() const; |
| auto operator<=>(const self&) const = default; |
| |
| self& operator++() { globalCount++; ++ptr_; return *this; } |
| self operator++(int) { |
| auto tmp = *this; |
| ++*this; |
| return tmp; |
| } |
| |
| self& operator--(); |
| self operator--(int); |
| }; |
| |
| struct CountedView : std::ranges::view_base { |
| int* begin_; |
| int* end_; |
| |
| CountedView(int* b, int* e) : begin_(b), end_(e) { } |
| |
| auto begin() { return CountedIter(begin_); } |
| auto begin() const { return CountedIter(begin_); } |
| auto end() { return sentinel_wrapper<CountedIter>(CountedIter(end_)); } |
| auto end() const { return sentinel_wrapper<CountedIter>(CountedIter(end_)); } |
| }; |
| |
| struct RASentRange : std::ranges::view_base { |
| using sent_t = sentinel_wrapper<random_access_iterator<int*>>; |
| using sent_const_t = sentinel_wrapper<random_access_iterator<const int*>>; |
| |
| int* begin_; |
| int* end_; |
| |
| constexpr RASentRange(int* b, int* e) : begin_(b), end_(e) { } |
| |
| constexpr random_access_iterator<int*> begin() { return random_access_iterator<int*>{begin_}; } |
| constexpr random_access_iterator<const int*> begin() const { return random_access_iterator<const int*>{begin_}; } |
| constexpr sent_t end() { return sent_t{random_access_iterator<int*>{end_}}; } |
| constexpr sent_const_t end() const { return sent_const_t{random_access_iterator<const int*>{end_}}; } |
| }; |
| |
| template<class T> |
| concept BeginInvocable = requires(T t) { t.begin(); }; |
| |
| constexpr bool test() { |
| int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8}; |
| |
| // Common bidirectional range. |
| { |
| auto rev = std::ranges::reverse_view(BidirRange{buffer, buffer + 8}); |
| assert(base(rev.begin().base()) == buffer + 8); |
| assert(base(std::move(rev).begin().base()) == buffer + 8); |
| |
| ASSERT_SAME_TYPE(decltype(rev.begin()), std::reverse_iterator<bidirectional_iterator<int*>>); |
| ASSERT_SAME_TYPE(decltype(std::move(rev).begin()), std::reverse_iterator<bidirectional_iterator<int*>>); |
| } |
| // Const common bidirectional range. |
| { |
| const auto rev = std::ranges::reverse_view(BidirRange{buffer, buffer + 8}); |
| assert(base(rev.begin().base()) == buffer + 8); |
| assert(base(std::move(rev).begin().base()) == buffer + 8); |
| |
| ASSERT_SAME_TYPE(decltype(rev.begin()), std::reverse_iterator<bidirectional_iterator<const int*>>); |
| ASSERT_SAME_TYPE(decltype(std::move(rev).begin()), std::reverse_iterator<bidirectional_iterator<const int*>>); |
| } |
| // Non-common, non-const (move only) bidirectional range. |
| { |
| auto rev = std::ranges::reverse_view(BidirSentRange<MoveOnly>{buffer, buffer + 8}); |
| assert(base(std::move(rev).begin().base()) == buffer + 8); |
| |
| ASSERT_SAME_TYPE(decltype(std::move(rev).begin()), std::reverse_iterator<bidirectional_iterator<int*>>); |
| } |
| // Non-common, non-const bidirectional range. |
| { |
| auto rev = std::ranges::reverse_view(BidirSentRange<Copyable>{buffer, buffer + 8}); |
| assert(base(rev.begin().base()) == buffer + 8); |
| assert(base(std::move(rev).begin().base()) == buffer + 8); |
| |
| ASSERT_SAME_TYPE(decltype(rev.begin()), std::reverse_iterator<bidirectional_iterator<int*>>); |
| ASSERT_SAME_TYPE(decltype(std::move(rev).begin()), std::reverse_iterator<bidirectional_iterator<int*>>); |
| } |
| // Non-common random access range. |
| // Note: const overload invalid for non-common ranges, though it would not be impossible |
| // to implement for random access ranges. |
| { |
| auto rev = std::ranges::reverse_view(RASentRange{buffer, buffer + 8}); |
| assert(base(rev.begin().base()) == buffer + 8); |
| assert(base(std::move(rev).begin().base()) == buffer + 8); |
| |
| ASSERT_SAME_TYPE(decltype(rev.begin()), std::reverse_iterator<random_access_iterator<int*>>); |
| ASSERT_SAME_TYPE(decltype(std::move(rev).begin()), std::reverse_iterator<random_access_iterator<int*>>); |
| } |
| { |
| static_assert( BeginInvocable< std::ranges::reverse_view<BidirSentRange<Copyable>>>); |
| static_assert(!BeginInvocable<const std::ranges::reverse_view<BidirSentRange<Copyable>>>); |
| } |
| |
| return true; |
| } |
| |
| int main(int, char**) { |
| test(); |
| static_assert(test()); |
| |
| { |
| // Make sure we cache begin. |
| int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8}; |
| CountedView view{buffer, buffer + 8}; |
| std::ranges::reverse_view rev(view); |
| assert(rev.begin().base().ptr_ == buffer + 8); |
| assert(globalCount == 8); |
| assert(rev.begin().base().ptr_ == buffer + 8); |
| assert(globalCount == 8); |
| } |
| |
| return 0; |
| } |