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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
// <iterator>
// reverse_iterator
// template<class Iterator1, three_way_comparable_with<Iterator1> Iterator2>
// constexpr compare_three_way_result_t<Iterator1, Iterator2>
// operator<=>(const reverse_iterator<Iterator1>& x,
// const reverse_iterator<Iterator2>& y);
#include <iterator>
#include <limits>
#include <cassert>
#include "test_macros.h"
#include "test_iterators.h"
template <class ItL, class ItR, class Ord>
constexpr void test(ItL l, ItR r, Ord x) {
const std::reverse_iterator<ItL> l1(l);
const std::reverse_iterator<ItR> r1(r);
ASSERT_SAME_TYPE(decltype(l1 <=> r1), Ord);
assert((l1 <=> r1) == x);
}
struct Iter {
using iterator_category = std::bidirectional_iterator_tag;
using pointer = char*;
using reference = char&;
using value_type = char;
using difference_type = double;
constexpr Iter(double value): m_value(value) {}
double m_value;
reference operator*() const;
private:
friend constexpr bool operator==(const Iter& l, const Iter& r) = default;
friend constexpr std::partial_ordering operator<=>(const Iter& l, const Iter& r) = default;
};
struct ConstIter {
using iterator_category = std::bidirectional_iterator_tag;
using pointer = const char*;
using reference = const char&;
using value_type = const char;
using difference_type = double;
constexpr ConstIter(double value): m_value(value) {}
constexpr ConstIter(Iter it): m_value(it.m_value) {}
double m_value;
reference operator*() const;
private:
friend constexpr bool operator==(const ConstIter& l, const ConstIter& r) = default;
friend constexpr std::partial_ordering operator<=>(const ConstIter& l, const ConstIter& r) = default;
};
constexpr bool tests() {
char s[] = "1234567890";
test(three_way_contiguous_iterator<const char*>(s),
three_way_contiguous_iterator<const char*>(s),
std::strong_ordering::equal);
test(three_way_contiguous_iterator<const char*>(s),
three_way_contiguous_iterator<const char*>(s+1),
std::strong_ordering::greater);
test(three_way_contiguous_iterator<const char*>(s+1),
three_way_contiguous_iterator<const char*>(s),
std::strong_ordering::less);
test(s, s, std::strong_ordering::equal);
test(s, s+1, std::strong_ordering::greater);
test(s+1, s, std::strong_ordering::less);
const char* cs = s;
test(cs, s, std::strong_ordering::equal);
test(cs, s+1, std::strong_ordering::greater);
test(cs+1, s, std::strong_ordering::less);
constexpr double nan = std::numeric_limits<double>::quiet_NaN();
test(Iter(0), ConstIter(nan), std::partial_ordering::unordered);
test(Iter(nan), Iter(nan), std::partial_ordering::unordered);
test(ConstIter(0), Iter(1), std::partial_ordering::greater);
test(ConstIter(3), Iter(2), std::partial_ordering::less);
test(ConstIter(7), Iter(7), std::partial_ordering::equivalent);
return true;
}
int main(int, char**) {
tests();
static_assert(tests());
return 0;
}
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