1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 // UNSUPPORTED: c++03, c++11, c++14, c++17 10 // UNSUPPORTED: libcpp-no-concepts 11 // UNSUPPORTED: libcpp-has-no-incomplete-ranges 12 13 // constexpr auto begin() requires (!simple-view<V>); 14 // constexpr auto begin() const requires range<const V>; 15 16 #include <ranges> 17 #include <cassert> 18 19 #include "test_macros.h" 20 #include "test_iterators.h" 21 #include "test_range.h" 22 #include "types.h" 23 24 struct NonCommonSimpleView : std::ranges::view_base { 25 int* begin() const; 26 sentinel_wrapper<int*> end() const; 27 size_t size() { return 0; } // deliberately non-const 28 }; 29 static_assert(std::ranges::sized_range<NonCommonSimpleView>); 30 static_assert(!std::ranges::sized_range<const NonCommonSimpleView>); 31 32 constexpr bool test() { 33 int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8}; 34 35 // sized_range && random_access_iterator 36 { 37 std::ranges::take_view<SizedRandomAccessView> tv(SizedRandomAccessView(buffer), 4); 38 assert(tv.begin() == SizedRandomAccessView(buffer).begin()); 39 ASSERT_SAME_TYPE(decltype(tv.begin()), RandomAccessIter); 40 } 41 42 { 43 const std::ranges::take_view<SizedRandomAccessView> tv(SizedRandomAccessView(buffer), 4); 44 assert(tv.begin() == SizedRandomAccessView(buffer).begin()); 45 ASSERT_SAME_TYPE(decltype(tv.begin()), RandomAccessIter); 46 } 47 48 // sized_range && !random_access_iterator 49 { 50 std::ranges::take_view<SizedForwardView> tv(SizedForwardView{buffer}, 4); 51 assert(tv.begin() == std::counted_iterator<ForwardIter>(ForwardIter(buffer), 4)); 52 ASSERT_SAME_TYPE(decltype(tv.begin()), std::counted_iterator<ForwardIter>); 53 } 54 55 { 56 const std::ranges::take_view<SizedForwardView> tv(SizedForwardView{buffer}, 4); 57 assert(tv.begin() == std::counted_iterator<ForwardIter>(ForwardIter(buffer), 4)); 58 ASSERT_SAME_TYPE(decltype(tv.begin()), std::counted_iterator<ForwardIter>); 59 } 60 61 // !sized_range 62 { 63 std::ranges::take_view<MoveOnlyView> tv(MoveOnlyView{buffer}, 4); 64 assert(tv.begin() == std::counted_iterator<int*>(buffer, 4)); 65 ASSERT_SAME_TYPE(decltype(tv.begin()), std::counted_iterator<int*>); 66 } 67 68 { 69 const std::ranges::take_view<MoveOnlyView> tv(MoveOnlyView{buffer}, 4); 70 assert(tv.begin() == std::counted_iterator<int*>(buffer, 4)); 71 ASSERT_SAME_TYPE(decltype(tv.begin()), std::counted_iterator<int*>); 72 } 73 74 // __simple_view<V> && sized_range<V> && !size_range<!V> 75 { 76 std::ranges::take_view<NonCommonSimpleView> tv{}; 77 ASSERT_SAME_TYPE(decltype(tv.begin()), std::counted_iterator<int*>); 78 ASSERT_SAME_TYPE(decltype(std::as_const(tv).begin()), std::counted_iterator<int*>); 79 } 80 81 return true; 82 } 83 84 int main(int, char**) { 85 test(); 86 static_assert(test()); 87 88 return 0; 89 } 90