forked from OSchip/llvm-project
83 lines
3.2 KiB
C++
83 lines
3.2 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// UNSUPPORTED: c++03, c++11, c++14, c++17
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// <compare>
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// <functional>
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// compare_three_way
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#include <compare>
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#include <cassert>
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#include <limits>
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#include <type_traits>
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#include "pointer_comparison_test_helper.h"
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template<class T, class U>
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constexpr auto test_sfinae(T t, U u)
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-> decltype(std::compare_three_way()(t, u), std::true_type{})
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{ return std::true_type{}; }
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constexpr auto test_sfinae(...)
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{ return std::false_type{}; }
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struct NotThreeWayComparable {
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std::strong_ordering operator<=>(const NotThreeWayComparable&) const;
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};
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ASSERT_SAME_TYPE(std::compare_three_way_result_t<NotThreeWayComparable>, std::strong_ordering);
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static_assert(!std::three_way_comparable<NotThreeWayComparable>); // it lacks operator==
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struct WeaklyOrdered {
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int i;
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friend constexpr std::weak_ordering operator<=>(const WeaklyOrdered&, const WeaklyOrdered&) = default;
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};
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constexpr bool test()
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{
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ASSERT_SAME_TYPE(decltype(std::compare_three_way()(1, 1)), std::strong_ordering);
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assert(std::compare_three_way()(1, 2) == std::strong_ordering::less);
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assert(std::compare_three_way()(1, 1) == std::strong_ordering::equal);
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assert(std::compare_three_way()(2, 1) == std::strong_ordering::greater);
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ASSERT_SAME_TYPE(decltype(std::compare_three_way()(WeaklyOrdered{1}, WeaklyOrdered{2})), std::weak_ordering);
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assert(std::compare_three_way()(WeaklyOrdered{1}, WeaklyOrdered{2}) == std::weak_ordering::less);
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assert(std::compare_three_way()(WeaklyOrdered{1}, WeaklyOrdered{1}) == std::weak_ordering::equivalent);
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assert(std::compare_three_way()(WeaklyOrdered{2}, WeaklyOrdered{1}) == std::weak_ordering::greater);
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ASSERT_SAME_TYPE(decltype(std::compare_three_way()(1.0, 1.0)), std::partial_ordering);
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double nan = std::numeric_limits<double>::quiet_NaN();
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assert(std::compare_three_way()(1.0, 2.0) == std::partial_ordering::less);
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assert(std::compare_three_way()(1.0, 1.0) == std::partial_ordering::equivalent);
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assert(std::compare_three_way()(2.0, 1.0) == std::partial_ordering::greater);
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assert(std::compare_three_way()(nan, nan) == std::partial_ordering::unordered);
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// Try heterogeneous comparison.
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ASSERT_SAME_TYPE(decltype(std::compare_three_way()(42.0, 42)), std::partial_ordering);
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assert(std::compare_three_way()(42.0, 42) == std::partial_ordering::equivalent);
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ASSERT_SAME_TYPE(decltype(std::compare_three_way()(42, 42.0)), std::partial_ordering);
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assert(std::compare_three_way()(42, 42.0) == std::partial_ordering::equivalent);
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return true;
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}
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int main(int, char**)
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{
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test();
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static_assert(test());
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do_pointer_comparison_test(std::compare_three_way());
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static_assert(test_sfinae(1, 2));
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static_assert(!test_sfinae(1, nullptr));
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static_assert(!test_sfinae(NotThreeWayComparable(), NotThreeWayComparable()));
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return 0;
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}
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