#ifndef BOOST_ANY_INCLUDED
#define BOOST_ANY_INCLUDED

// what:  variant type any
// who:   contributed by Kevlin Henney,
//        with features contributed and bugs found by
//        Ed Brey, Mark Rodgers, Peter Dimov, and James Curran
// when:  October 2000
// where: tested with BCC 5.5 and MSVC 6.0

#include <algorithm>
#include <typeinfo>

#ifdef COMPILING_MSVC
#define MSVC_INCLUDE(code) code
#define MSVC_EXCLUDE(code)
#else
#define MSVC_INCLUDE(code)
#define MSVC_EXCLUDE(code) code
#endif

namespace boost
{
    class any
    {
    public: // structors

        any()
          : content(0)
        {
        }

        template<typename ValueType>
        any(const ValueType & value)
          : content(new holder<ValueType>(value))
        {
        }

        MSVC_INCLUDE(template<>)
        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;
        }

        MSVC_INCLUDE(template<>)
        any & operator=(const any & rhs)
        {
            any(rhs).swap(*this);
            return *this;
        }

    public: // queries

        operator const void *() const
        {
            return content ? &typeid(void) : 0;
        }

        const std::type_info & type() const
        {
            return content ? content->type() : typeid(void);
        }

        template<typename ValueType>
        bool copy_to(ValueType & value) const
        {
            const ValueType * copyable =
                to_ptr MSVC_EXCLUDE(<ValueType>)(MSVC_INCLUDE(&value));

            if(copyable)
            {
                value = *copyable;
            }

            return copyable;
        }

        template<typename ValueType>
        ValueType * to_ptr(MSVC_INCLUDE(ValueType * = 0))
        {
            return type() == typeid(ValueType)
                        ? &static_cast<holder<ValueType> *>(content)->held
                        : 0;
        }

        template<typename ValueType>
        const ValueType * to_ptr(MSVC_INCLUDE(ValueType * dummy = 0)) const
        {
            return const_cast<any *>(this)->
                        to_ptr MSVC_EXCLUDE(<ValueType>)(MSVC_INCLUDE(dummy));
        }

    private: // types

        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;

        };

    private: // representation

        placeholder * content;

    };

    class bad_any_cast : public std::bad_cast
    {
    public:
        virtual const char *what() const
        {
            return "boost::bad_any_cast: "
                   "failed conversion using boost::any_cast";
        }
    };

    template<typename ValueType>
    ValueType any_cast(const any & operand)
    {
        const ValueType * result =
            operand.to_ptr MSVC_EXCLUDE(<ValueType>)(
                MSVC_INCLUDE(static_cast<ValueType *>(0)));

        if(!result)
        {
            throw bad_any_cast();
        }

        return *result;
    }
}

// Copyright Kevlin Henney, 2000. All rights reserved.
//
// Permission to use, copy, modify, and distribute this software for any
// purpose is hereby granted without fee, provided that this copyright and
// permissions notice appear in all copies and derivatives, and that no
// charge may be made for the software and its documentation except to cover
// cost of distribution.
//
// This software is provided "as is" without express or implied warranty.

#endif