Program Listing for File half_nonnegative.hpp

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/*
 * Copyright 2019 Denis Yaroshevskiy
 *
 * 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.
 */

#ifndef ALGO_HALF_NONNEGATIVE_H
#define ALGO_HALF_NONNEGATIVE_H

#include <type_traits>
#include <utility>

namespace algo
{

template <typename N>
auto half_nonnegative(N n) noexcept ->
    typename std::enable_if<std::is_integral<N>::value, N>::type
{
    using UN = typename std::make_unsigned<N>::type;
    return static_cast<N>(static_cast<UN>(n) / 2);
}

template <typename N>
auto half_nonnegative(N n) noexcept ->
    typename std::enable_if<!std::is_integral<N>::value, N>::type
{
    return std::move(n) / 2;
}

} // namespace algo

#endif // ALGO_HALF_NONNEGATIVE_H