MPL.h

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// MPL.h
//
// Copyright (c) 2014, 2015 Michael Imamura.
//
// Licensed under GrokkSoft HoverRace SourceCode License v1.0(the "License");
// you may not use this file except in compliance with the License.
//
// A copy of the license should have been attached to the package from which
// you have taken this file. If you can not find the license you can not use
// this file.
//
//
// The author makes no representations about the suitability of
// this software for any purpose.  It is provided "as is" "AS IS",
// 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

#if defined(_WIN32) && defined(HR_ENGINE_SHARED)
#   ifdef MR_ENGINE
#       define MR_DllDeclare   __declspec( dllexport )
#   else
#       define MR_DllDeclare   __declspec( dllimport )
#   endif
#else
#   define MR_DllDeclare
#endif

namespace HoverRace {
namespace Display {
namespace MPL {

template<class C>
struct HasSetSize
{
private:
    template<class T>
    static auto check(T*) ->
        decltype(std::declval<T>().SetSize(std::declval<Vec2>()),
        std::true_type());

    template<class>
    static std::false_type check(...);

    using type = decltype(check<C>(nullptr));

public:
    static const bool value = type::value;
};

template<class T>
typename std::enable_if<MPL::HasSetSize<T>::value, void>::type
inline SetSize(T &widget, double w, double h)
{
    widget.SetSize(Vec2(w, h));
}

template<class T>
typename std::enable_if<MPL::HasSetSize<T>::value, void>::type
inline SetSize(T &widget, Vec2 &&vec)
{
    widget.SetSize(std::forward<Vec2>(vec));
}

template<class T>
typename std::enable_if<!MPL::HasSetSize<T>::value, void>::type
inline SetSize(T&, double, double)
{
    // Do nothing.
}

template<class T>
typename std::enable_if<!MPL::HasSetSize<T>::value, void>::type
inline SetSize(T&, Vec2&&)
{
    // Do nothing.
}

}  // namespace MPL
}  // namespace Display
}  // namespace HoverRace

#undef MR_DllDeclare