AuROXTL/Include/auROXTL/auSwapExchangeUtils.hpp

/***
    Copyright (C) 2022 J Reece Wilson (a/k/a "Reece"). All rights reserved.
    File: auSwapExchangeUtils.hpp
    Date: 2022-3-27
    Author: Reece
***/
#pragma once

namespace __audetail
{
    template <class T>
    struct AuHasSwap
    {
        template <class C> static constexpr AuTrueType  Test(decltype(static_cast<void(C:: *)(C &) const>(&C::Swap)));
        template <class C> static constexpr AuFalseType Test(...);
        using type = decltype(Test<T>(0));
    };

    template <class T>
    struct AuHasswap
    {
        template <class C> static constexpr AuTrueType  Test(decltype(static_cast<void(C:: *)(C &) const>(&C::swap)));
        template <class C> static constexpr AuFalseType Test(...);
        using type = decltype(Test<T>(0));
    };

    template <class T>
    constexpr inline bool AuAuHasSwap_v = AuHasSwap<T>::type::value;

    template <class T>
    constexpr inline bool AuAuHasswap_v = AuHasswap<T>::type::value;
}

template <class T, class U = T>
inline T AuExchange(T &obj, U &&newValue)
{
    T oldValue = AuMove(obj);
    obj = AuForward<U>(newValue);
    return oldValue;
}

#if !defined(AURORA_RUNTIME_SWAP) && !defined(AURORA_SWAP_COCKBLOCK)
    #define AURORA_RUNTIME_SWAP std::swap
#endif

template <class T>
inline void AuSwap(T &a, T &b)
{
    if constexpr (__audetail::AuAuHasSwap_v<T>)
    {
        a.Swap(b);
        return;
    }

    if constexpr (__audetail::AuAuHasswap_v<T>)
    {
        a.swap(b);
        return;
    }

#if defined(AURORA_RUNTIME_SWAP)
    AURORA_RUNTIME_SWAP(a, b);
    return;
#else
   static_assert(false, "cannot swap T");
#endif
}