MyGUI_Any.h

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/*
 * This source file is part of MyGUI. For the latest info, see http://mygui.info/
 * Distributed under the MIT License
 * (See accompanying file COPYING.MIT or copy at http://opensource.org/licenses/MIT)
 */

// -- Based on boost::any, original copyright information follows --
// Copyright Kevlin Henney, 2000, 2001, 2002. All rights reserved.
//
// Distributed under the Boost Software License, Version 1.0.
// (See at http://www.boost.org/LICENSE_1_0.txt)
// -- End original copyright --

#ifndef __MYGUI_ANY_H__
#define __MYGUI_ANY_H__

#include "MyGUI_Prerequest.h"
#include "MyGUI_Diagnostic.h"
#include <algorithm>

#include <typeinfo>

namespace MyGUI
{

    class MYGUI_EXPORT Any
    {
    public:
        struct AnyEmpty { };
        static AnyEmpty Null;

        Any();
        Any(const Any::AnyEmpty& value);
        Any(const Any& other);

        template<typename ValueType>
        Any(const ValueType& value) :
            mContent(new Holder<ValueType>(value))
        {
        }

        ~Any();

        Any& swap(Any& rhs);

        template<typename ValueType>
        Any& operator = (const ValueType& rhs)
        {
            Any(rhs).swap(*this);
            return *this;
        }

        Any& operator = (const Any::AnyEmpty& rhs);
        Any& operator = (const Any& rhs);

        bool empty() const;

        const std::type_info& getType() const;

        template<typename ValueType>
        ValueType* castType(bool _throw = true) const
        {
            if (this->getType() == typeid(ValueType))
                return &static_cast<Any::Holder<ValueType> *>(this->mContent)->held;
            MYGUI_ASSERT(!_throw, "Bad cast from type '" << getType().name() << "' to '" << typeid(ValueType).name() << "'");
            return nullptr;
        }

        void* castUnsafe() const;

    private:
        class Placeholder
        {
        public:
            virtual ~Placeholder() { }

        public:
            virtual const std::type_info& getType() const = 0;
            virtual Placeholder* clone() const = 0;
        };

        template<typename ValueType>
        class Holder :
            public Placeholder
        {
        public:
            Holder(const ValueType& value) :
                held(value)
            {
            }

        public:
            virtual const std::type_info& getType() const
            {
                return typeid(ValueType);
            }

            virtual Placeholder* clone() const
            {
                return new Holder(held);
            }

        public:
            ValueType held;

        private:
            Holder& operator=(const Holder&);
        };

    private:
        Placeholder* mContent;
    };

} // namespace MyGUI

#endif // __MYGUI_ANY_H__