// See http://www.boost.org/libs/any for Documentation.

#ifndef BOOST_ANY_INCLUDED

#define BOOST_ANY_INCLUDED

// what:  variant type boost::any

// who:   contributed by Kevlin Henney,

//        with features contributed and bugs found by

//        Ed Brey, Mark Rodgers, Peter Dimov, and James Curran

// when:  July 2001

// where: tested with BCC 5.5, MSVC 6.0, and g++ 2.95

#include <algorithm>

#include <typeinfo>

#include "boost/config.hpp"

#include <boost/type_traits/remove_reference.hpp>

#include <boost/type_traits/is_reference.hpp>

#include <boost/throw_exception.hpp>

#include <boost/static_assert.hpp>

namespace boost

{

    class any

    {

    public: // structors

        any()

          : content(0)

        {

        }

        template<typename ValueType>

        any(const ValueType & value)

          : content(new holder<ValueType>(value))

        {

        }

        any(const any & other)

          : content(other.content ? other.content->clone() : 0)

        {

        }

        ~any()

        {

            delete content;

        }

    public: // modifiers

        any & swap(any & rhs)

        {

            std::swap(content, rhs.content);

            return *this;

        }

        template<typename ValueType>

        any & operator=(const ValueType & rhs)

        {

            any(rhs).swap(*this);

            return *this;

        }

        any & operator=(const any & rhs)

        {

            any(rhs).swap(*this);

            return *this;

        }

    public: // queries

        bool empty() const

        {

            return !content;

        }

        const std::type_info & type() const

        {

            return content ? content->type() : typeid(void);

        }

#ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS

    private: // types

#else

    public: // types (public so any_cast can be non-friend)

#endif

        class placeholder

        {

        public: // structors

            virtual ~placeholder()

            {

            }

        public: // queries

            virtual const std::type_info & type() const = 0;

            virtual placeholder * clone() const = 0;

        };

        template<typename ValueType>

        class holder : public placeholder

        {

        public: // structors

            holder(const ValueType & value)

              : held(value)

            {

            }

        public: // queries

            virtual const std::type_info & type() const

            {

                return typeid(ValueType);

            }

            virtual placeholder * clone() const

            {

                return new holder(held);

            }

        public: // representation

            ValueType held;

        };

#ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS

    private: // representation

        template<typename ValueType>

        friend ValueType * any_cast(any *);

        template<typename ValueType>

        friend ValueType * unsafe_any_cast(any *);

#else

    public: // representation (public so any_cast can be non-friend)

#endif

        placeholder * content;

    };

    class bad_any_cast : public std::bad_cast

    {

    public:

        virtual const char * what() const throw()

        {

            return "boost::bad_any_cast: "

                   "failed conversion using boost::any_cast";

        }

    };

    template<typename ValueType>

    ValueType * any_cast(any * operand)

    {

        return operand && operand->type() == typeid(ValueType)

                    ? &static_cast<any::holder<ValueType> *>(operand->content)->held

                    : 0;

    }

    template<typename ValueType>

    const ValueType * any_cast(const any * operand)

    {

        return any_cast<ValueType>(const_cast<any *>(operand));

    }

    template<typename ValueType>

    ValueType any_cast(const any & operand)

    {

        typedef BOOST_DEDUCED_TYPENAME remove_reference<ValueType>::type nonref;

#ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION

        // If 'nonref' is still reference type, it means the user has not

        // specialized 'remove_reference'.

        // Please use BOOST_BROKEN_COMPILER_TYPE_TRAITS_SPECIALIZATION macro

        // to generate specialization of remove_reference for your class

        // See type traits library documentation for details

        BOOST_STATIC_ASSERT(!is_reference<nonref>::value);

#endif

        const nonref * result = any_cast<nonref>(&operand);

        if(!result)

            boost::throw_exception(bad_any_cast());

        return *result;

    }

    template<typename ValueType>

    ValueType any_cast(any & operand)

    {

        typedef BOOST_DEDUCED_TYPENAME remove_reference<ValueType>::type nonref;

#ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION

        // The comment in the above version of 'any_cast' explains when this

        // assert is fired and what to do.

        BOOST_STATIC_ASSERT(!is_reference<nonref>::value);

#endif

        nonref * result = any_cast<nonref>(&operand);

        if(!result)

            boost::throw_exception(bad_any_cast());

        return *result;

    }

    // Note: The "unsafe" versions of any_cast are not part of the

    // public interface and may be removed at any time. They are

    // required where we know what type is stored in the any and can't

    // use typeid() comparison, e.g., when our types may travel across

    // different shared libraries.

    template<typename ValueType>

    inline ValueType * unsafe_any_cast(any * operand)

    {

        return &static_cast<any::holder<ValueType> *>(operand->content)->held;

    }

    template<typename ValueType>

    inline const ValueType * unsafe_any_cast(const any * operand)

    {

        return unsafe_any_cast<ValueType>(const_cast<any *>(operand));

    }

}

// Copyright Kevlin Henney, 2000, 2001, 2002. All rights reserved.

//

// Distributed under the Boost Software License, Version 1.0. (See

// accompanying file LICENSE_1_0.txt or copy at

// http://www.boost.org/LICENSE_1_0.txt)

#endif