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//===----------------------------------------------------------------------===//
//
// 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 sentinel(sentinel<!Const> s);
// requires Const && convertible_to<sentinel_t<V>, sentinel_t<Base>>;
#include <cassert>
#include <ranges>
#include "../types.h"
#include "test_range.h"
template <class T>
struct convertible_sentinel_wrapper {
explicit convertible_sentinel_wrapper() = default;
constexpr convertible_sentinel_wrapper(const T& it) : it_(it) {}
template <class U>
requires std::convertible_to<const U&, T>
constexpr convertible_sentinel_wrapper(const convertible_sentinel_wrapper<U>& other) : it_(other.it_) {}
constexpr friend bool operator==(convertible_sentinel_wrapper const& self, const T& other) {
return self.it_ == other;
}
T it_;
};
struct ConstConvertibleView : BufferView<BufferView<int*>*> {
using BufferView<BufferView<int*>*>::BufferView;
using sentinel = convertible_sentinel_wrapper<BufferView<int*>*>;
using const_sentinel = convertible_sentinel_wrapper<const BufferView<int*>*>;
constexpr BufferView<int*>* begin() { return data_; }
constexpr const BufferView<int*>* begin() const { return data_; }
constexpr sentinel end() { return sentinel(data_ + size_); }
constexpr const_sentinel end() const { return const_sentinel(data_ + size_); }
};
static_assert(!std::ranges::common_range<ConstConvertibleView>);
static_assert(std::convertible_to<std::ranges::sentinel_t<ConstConvertibleView>,
std::ranges::sentinel_t<ConstConvertibleView const>>);
static_assert(!simple_view<ConstConvertibleView>);
constexpr bool test() {
int buffer[4][4] = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}, {13, 14, 15, 16}};
{
BufferView<int*> inners[] = {buffer[0], buffer[1], buffer[2]};
ConstConvertibleView outer(inners);
std::ranges::join_view jv(outer);
auto sent1 = jv.end();
std::ranges::sentinel_t<const decltype(jv)> sent2 = sent1;
assert(std::as_const(jv).begin() != sent2);
assert(std::ranges::next(std::as_const(jv).begin(), 12) == sent2);
// We cannot create a non-const sentinel from a const sentinel.
static_assert(!std::constructible_from<decltype(sent1), decltype(sent2)>);
}
{
// cannot create a const sentinel from a non-const sentinel if the underlying
// const sentinel cannot be created from the underlying non-const sentinel
using Inner = BufferView<int*>;
using ConstInconvertibleOuter =
BufferView<forward_iterator<const Inner*>, sentinel_wrapper<forward_iterator<const Inner*>>,
bidirectional_iterator<Inner*>, sentinel_wrapper<bidirectional_iterator<Inner*>>>;
using JoinView = std::ranges::join_view<ConstInconvertibleOuter>;
using sentinel_t = std::ranges::sentinel_t<JoinView>;
using const_sentinel_t = std::ranges::sentinel_t<const JoinView>;
static_assert(!std::constructible_from<sentinel_t, const_sentinel_t>);
static_assert(!std::constructible_from<const_sentinel_t, sentinel_t>);
}
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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