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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 sentinel_for<sentinel_t<Base>, iterator_t<maybe-const<OtherConst, V>>>
// friend constexpr bool operator==(const iterator<OtherConst>& x, const sentinel& y);
#include <array>
#include <cassert>
#include <ranges>
#include "../types.h"
template <bool Const>
struct Iter {
std::tuple<int>* it_;
using value_type = std::tuple<int>;
using difference_type = std::intptr_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 CrossComparableSent {
std::tuple<int>* end_;
template <bool C>
constexpr bool operator==(const Iter<C>& i) const {
return i.it_ == end_;
}
};
template <template <bool> typename St>
struct Range : TupleBufferView {
using TupleBufferView::TupleBufferView;
constexpr Iter<false> begin() { return Iter<false>{buffer_}; }
constexpr Iter<true> begin() const { return Iter<true>{buffer_}; }
constexpr St<false> end() { return St<false>{buffer_ + size_}; }
constexpr St<true> end() const { return St<true>{buffer_ + size_}; }
};
using R = Range<Sent>;
using CrossComparableR = Range<CrossComparableSent>;
// Test Constraint
template <class I, class S>
concept HasEqual = requires(const I i, const S s) { i == s; };
using std::ranges::elements_view;
using std::ranges::iterator_t;
using std::ranges::sentinel_t;
static_assert(HasEqual<iterator_t<elements_view<R, 0>>, //
sentinel_t<elements_view<R, 0>>>);
static_assert(!HasEqual<iterator_t<const elements_view<R, 0>>, //
sentinel_t<elements_view<R, 0>>>);
static_assert(!HasEqual<iterator_t<elements_view<R, 0>>, //
sentinel_t<const elements_view<R, 0>>>);
static_assert(HasEqual<iterator_t<const elements_view<R, 0>>, //
sentinel_t<const elements_view<R, 0>>>);
static_assert(HasEqual<iterator_t<elements_view<R, 0>>, //
sentinel_t<elements_view<R, 0>>>);
static_assert(HasEqual<iterator_t<const elements_view<CrossComparableR, 0>>, //
sentinel_t<elements_view<CrossComparableR, 0>>>);
static_assert(HasEqual<iterator_t<elements_view<CrossComparableR, 0>>, //
sentinel_t<const elements_view<CrossComparableR, 0>>>);
static_assert(HasEqual<iterator_t<const elements_view<CrossComparableR, 0>>, //
sentinel_t<const elements_view<CrossComparableR, 0>>>);
template <class R, bool ConstIter, bool ConstSent>
constexpr void testOne() {
auto getBegin = [](auto&& rng) {
if constexpr (ConstIter) {
return std::as_const(rng).begin();
} else {
return rng.begin();
}
};
auto getEnd = [](auto&& rng) {
if constexpr (ConstSent) {
return std::as_const(rng).end();
} else {
return rng.end();
}
};
// iter == sentinel.base
{
std::tuple<int> buffer[] = {{1}};
R v{buffer};
std::ranges::elements_view<R, 0> ev(v);
auto iter = getBegin(ev);
auto st = getEnd(ev);
++iter;
assert(iter == st);
}
// iter != sentinel.base
{
std::tuple<int> buffer[] = {{1}};
R v{buffer};
std::ranges::elements_view<R, 0> ev(v);
auto iter = getBegin(ev);
auto st = getEnd(ev);
assert(iter != st);
}
// empty range
{
std::array<std::tuple<int>, 0> arr;
R v{arr};
std::ranges::elements_view<R, 0> ev(v);
auto iter = getBegin(ev);
auto sent = getEnd(ev);
assert(iter == sent);
}
}
constexpr bool test() {
testOne<R, false, false>();
testOne<R, true, true>();
testOne<CrossComparableR, false, false>();
testOne<CrossComparableR, true, true>();
testOne<CrossComparableR, true, false>();
testOne<CrossComparableR, false, true>();
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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