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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
// template<bool OtherConst>
// requires sized_sentinel_for<sentinel_t<Base>, iterator_t<maybe-const<OtherConst, V>>>
// friend constexpr range_difference_t<maybe-const<OtherConst, V>>
// operator-(const iterator<OtherConst>& x, const sentinel& y);
//
// template<bool OtherConst>
// requires sized_sentinel_for<sentinel_t<Base>, iterator_t<maybe-const<OtherConst, V>>>
// friend constexpr range_difference_t<maybe-const<OtherConst, V>>
// operator-(const sentinel& x, const iterator<OtherConst>& y);
#include <cassert>
#include <concepts>
#include <cstddef>
#include <functional>
#include <ranges>
#include <tuple>
#include "../types.h"
template <bool Const>
struct Iter {
std::tuple<int>* it_;
using value_type = std::tuple<int>;
using difference_type = std::ptrdiff_t;
using iterator_concept = std::input_iterator_tag;
constexpr decltype(auto) operator*() const { return *it_; }
constexpr Iter& operator++() {
++it_;
return *this;
}
constexpr void operator++(int) { ++it_; }
};
template <bool Const>
struct Sent {
std::tuple<int>* end_;
constexpr bool operator==(const Iter<Const>& i) const { return i.it_ == end_; }
};
template <bool Const>
struct SizedSent {
std::tuple<int>* end_;
constexpr bool operator==(const Iter<Const>& i) const { return i.it_ == end_; }
friend constexpr auto operator-(const SizedSent& st, const Iter<Const>& it) { return st.end_ - it.it_; }
friend constexpr auto operator-(const Iter<Const>& it, const SizedSent& st) { return it.it_ - st.end_; }
};
template <bool Const>
struct CrossSizedSent {
std::tuple<int>* end_;
template <bool C>
constexpr bool operator==(const Iter<C>& i) const {
return i.it_ == end_;
}
template <bool C>
friend constexpr auto operator-(const CrossSizedSent& st, const Iter<C>& it) {
return st.end_ - it.it_;
}
template <bool C>
friend constexpr auto operator-(const Iter<C>& it, const CrossSizedSent& st) {
return it.it_ - st.end_;
}
};
template <template <bool> class It, template <bool> class St>
struct Range : TupleBufferView {
using TupleBufferView::TupleBufferView;
using iterator = It<false>;
using sentinel = St<false>;
using const_iterator = It<true>;
using const_sentinel = St<true>;
constexpr iterator begin() { return {buffer_}; }
constexpr const_iterator begin() const { return {buffer_}; }
constexpr sentinel end() { return sentinel{buffer_ + size_}; }
constexpr const_sentinel end() const { return const_sentinel{buffer_ + size_}; }
};
template <class T, class U>
concept HasMinus = requires(const T t, const U u) { t - u; };
template <class BaseRange>
using ElementsView = std::ranges::elements_view<BaseRange, 0>;
template <class BaseRange>
using ElemIter = std::ranges::iterator_t<ElementsView<BaseRange>>;
template <class BaseRange>
using EleConstIter = std::ranges::iterator_t<const ElementsView<BaseRange>>;
template <class BaseRange>
using EleSent = std::ranges::sentinel_t<ElementsView<BaseRange>>;
template <class BaseRange>
using EleConstSent = std::ranges::sentinel_t<const ElementsView<BaseRange>>;
constexpr void testConstraints() {
// base is not sized
{
using Base = Range<Iter, Sent>;
static_assert(!HasMinus<EleSent<Base>, ElemIter<Base>>);
static_assert(!HasMinus<ElemIter<Base>, EleSent<Base>>);
static_assert(!HasMinus<EleSent<Base>, EleConstIter<Base>>);
static_assert(!HasMinus<EleConstIter<Base>, EleSent<Base>>);
static_assert(!HasMinus<EleConstSent<Base>, EleConstIter<Base>>);
static_assert(!HasMinus<EleConstIter<Base>, EleConstSent<Base>>);
static_assert(!HasMinus<EleConstSent<Base>, ElemIter<Base>>);
static_assert(!HasMinus<ElemIter<Base>, EleConstSent<Base>>);
}
// base is sized but not cross const
{
using Base = Range<Iter, SizedSent>;
static_assert(HasMinus<EleSent<Base>, ElemIter<Base>>);
static_assert(HasMinus<ElemIter<Base>, EleSent<Base>>);
static_assert(!HasMinus<EleSent<Base>, EleConstIter<Base>>);
static_assert(!HasMinus<EleConstIter<Base>, EleSent<Base>>);
static_assert(HasMinus<EleConstSent<Base>, EleConstIter<Base>>);
static_assert(HasMinus<EleConstIter<Base>, EleConstSent<Base>>);
static_assert(!HasMinus<EleConstSent<Base>, ElemIter<Base>>);
static_assert(!HasMinus<ElemIter<Base>, EleConstSent<Base>>);
}
// base is cross const sized
{
using Base = Range<Iter, CrossSizedSent>;
static_assert(HasMinus<EleSent<Base>, ElemIter<Base>>);
static_assert(HasMinus<ElemIter<Base>, EleSent<Base>>);
static_assert(HasMinus<EleSent<Base>, EleConstIter<Base>>);
static_assert(HasMinus<EleConstIter<Base>, EleSent<Base>>);
static_assert(HasMinus<EleConstSent<Base>, EleConstIter<Base>>);
static_assert(HasMinus<EleConstIter<Base>, EleConstSent<Base>>);
static_assert(HasMinus<EleConstSent<Base>, ElemIter<Base>>);
static_assert(HasMinus<ElemIter<Base>, EleConstSent<Base>>);
}
}
constexpr bool test() {
std::tuple<int> buffer[] = {{1}, {2}, {3}, {4}, {5}};
// base is sized but not cross const
{
using Base = Range<Iter, SizedSent>;
Base base{buffer};
auto ev = base | std::views::elements<0>;
auto iter = ev.begin();
auto const_iter = std::as_const(ev).begin();
auto sent = ev.end();
auto const_sent = std::as_const(ev).end();
assert(iter - sent == -5);
assert(sent - iter == 5);
assert(const_iter - const_sent == -5);
assert(const_sent - const_iter == 5);
}
// base is cross const sized
{
using Base = Range<Iter, CrossSizedSent>;
Base base{buffer};
auto ev = base | std::views::elements<0>;
auto iter = ev.begin();
auto const_iter = std::as_const(ev).begin();
auto sent = ev.end();
auto const_sent = std::as_const(ev).end();
assert(iter - sent == -5);
assert(sent - iter == 5);
assert(iter - const_sent == -5);
assert(const_sent - iter == 5);
assert(const_iter - sent == -5);
assert(sent - const_iter == 5);
assert(const_iter - const_sent == -5);
assert(const_sent - const_iter == 5);
}
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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