89 lines · cpp
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-exception6//7//===----------------------------------------------------------------------===//8 9// UNSUPPORTED: c++03, c++11, c++14, c++1710 11// constexpr auto size() requires sized_range<V>12// constexpr auto size() const requires sized_range<const V>13 14#include <cassert>15#include <ranges>16#include <tuple>17#include <utility>18 19#include "types.h"20 21template <class T>22concept HasSize = requires(T t) { t.size(); };23 24static_assert(HasSize<std::ranges::elements_view<SimpleCommon, 0>>);25static_assert(HasSize<const std::ranges::elements_view<SimpleCommon, 0>>);26 27struct NonSized : std::ranges::view_base {28 using iterator = forward_iterator<std::tuple<int>*>;29 iterator begin() const;30 iterator end() const;31};32static_assert(!std::ranges::sized_range<NonSized>);33static_assert(!std::ranges::sized_range<const NonSized>);34 35static_assert(!HasSize<std::ranges::elements_view<NonSized, 0>>);36static_assert(!HasSize<const std::ranges::elements_view<NonSized, 0>>);37 38struct SizedNonConst : TupleBufferView {39 using TupleBufferView::TupleBufferView;40 41 using iterator = forward_iterator<std::tuple<int>*>;42 constexpr auto begin() const { return iterator{buffer_}; }43 constexpr auto end() const { return iterator{buffer_ + size_}; }44 constexpr std::size_t size() { return size_; }45};46 47static_assert(HasSize<std::ranges::elements_view<SizedNonConst, 0>>);48static_assert(!HasSize<const std::ranges::elements_view<SizedNonConst, 0>>);49 50struct OnlyConstSized : TupleBufferView {51 using TupleBufferView::TupleBufferView;52 53 using iterator = forward_iterator<std::tuple<int>*>;54 constexpr auto begin() const { return iterator{buffer_}; }55 constexpr auto end() const { return iterator{buffer_ + size_}; }56 constexpr std::size_t size() const { return size_; }57 constexpr std::size_t size() = delete;58};59 60static_assert(HasSize<const OnlyConstSized>);61static_assert(HasSize<std::ranges::elements_view<OnlyConstSized, 0>>);62static_assert(HasSize<const std::ranges::elements_view<OnlyConstSized, 0>>);63 64constexpr bool test() {65 std::tuple<int> buffer[] = {{1}, {2}, {3}};66 67 // non-const and const are sized68 {69 auto ev = std::views::elements<0>(buffer);70 assert(ev.size() == 3);71 assert(std::as_const(ev).size() == 3);72 }73 74 {75 // const-view non-sized range76 auto ev = std::views::elements<0>(SizedNonConst{buffer});77 assert(ev.size() == 3);78 }79 80 return true;81}82 83int main(int, char**) {84 test();85 static_assert(test());86 87 return 0;88}89