xchg.hpp

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/*
 * SPDX-Licence-Identifier: MIT
 *
 * Copyright 2025 Larry Chips
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the “Software”), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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 * SOFTWARE.
 */
#pragma once
 
#include "ugmisc/features.hpp"
 
#ifdef UGMISC_HAVE_CONSTEXPR_EXCHANGE
#include <algorithm>
#endif
#include <utility>
 

 
 
 
 
namespace ugmisc {
 
 
 

template<class T, class U=T>
constexpr T xchg(T& object, U&& new_value) {
    if constexpr ( Features::constexpr_swap_algorithms ) {
        return std::exchange(object, std::forward<U>(new_value));
    } else {
        T ret{std::move(object)};
        object = std::move(new_value);
        return ret;
    }
}
 
 
 
 
} /* ::ugmisc */