vn-verdnaturachat/ios/Pods/Folly/folly/lang/Ordering.h

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2.0 KiB
C++

/*
* Copyright 2018-present Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
namespace folly {
enum class ordering : int { lt = -1, eq = 0, gt = 1 };
template <typename T>
constexpr ordering to_ordering(T c) {
return ordering(int(c < T(0)) * -1 + int(c > T(0)));
}
namespace detail {
template <typename C, ordering o, bool ne>
struct cmp_pred : private C {
using C::C;
template <typename A, typename B>
constexpr bool operator()(A&& a, B&& b) const {
return ne ^ (C::operator()(static_cast<A&&>(a), static_cast<B&&>(b)) == o);
}
};
} // namespace detail
template <typename C>
struct compare_equal_to : detail::cmp_pred<C, ordering::eq, 0> {
using detail::cmp_pred<C, ordering::eq, 0>::cmp_pred;
};
template <typename C>
struct compare_not_equal_to : detail::cmp_pred<C, ordering::eq, 1> {
using detail::cmp_pred<C, ordering::eq, 1>::cmp_pred;
};
template <typename C>
struct compare_less : detail::cmp_pred<C, ordering::lt, 0> {
using detail::cmp_pred<C, ordering::lt, 0>::cmp_pred;
};
template <typename C>
struct compare_less_equal : detail::cmp_pred<C, ordering::gt, 1> {
using detail::cmp_pred<C, ordering::gt, 1>::cmp_pred;
};
template <typename C>
struct compare_greater : detail::cmp_pred<C, ordering::gt, 0> {
using detail::cmp_pred<C, ordering::gt, 0>::cmp_pred;
};
template <typename C>
struct compare_greater_equal : detail::cmp_pred<C, ordering::lt, 1> {
using detail::cmp_pred<C, ordering::lt, 1>::cmp_pred;
};
} // namespace folly