    // Copyright (C) 2010  Davis E. King (davis@dlib.net)
    // License: Boost Software License   See LICENSE.txt for the full license.
    #ifndef DLIB_AnY_H_
    #define DLIB_AnY_H_

    #include "any_abstract.h"
    #include "../smart_pointers.h"
    #include <typeinfo>

    namespace dlib
    {

    // ----------------------------------------------------------------------------------------

        class bad_any_cast : public std::bad_cast
        {
        public:
              virtual const char * what() const throw()
              {
                  return "bad_any_cast";
              }
        };

    // ----------------------------------------------------------------------------------------

        class any
        {

        public:

            any()
            {
            }

            any (
                const any& item
            )
            {
                if (item.data)
                {
                    item.data->copy_to(data);
                }
            }

            template <typename T>
            any (
                const T& item
            )
            {
                typedef typename basic_type<T>::type U;
                data.reset(new derived<U>(item));
            }

            void clear (
            )
            {
                data.reset();
            }

            template <typename T>
            bool contains (
            ) const
            {
                typedef typename basic_type<T>::type U;
                return dynamic_cast<derived<U>*>(data.get()) != 0;
            }

            bool is_empty(
            ) const
            {
                return data.get() == 0;
            }

            template <typename T>
            T& cast_to(
            )
            {
                typedef typename basic_type<T>::type U;
                derived<U>* d = dynamic_cast<derived<U>*>(data.get());
                if (d == 0)
                {
                    throw bad_any_cast();
                }

                return d->item;
            }

            template <typename T>
            const T& cast_to(
            ) const
            {
                typedef typename basic_type<T>::type U;
                derived<U>* d = dynamic_cast<derived<U>*>(data.get());
                if (d == 0)
                {
                    throw bad_any_cast();
                }

                return d->item;
            }

            template <typename T>
            T& get(
            )
            {
                typedef typename basic_type<T>::type U;
                derived<U>* d = dynamic_cast<derived<U>*>(data.get());
                if (d == 0)
                {
                    d = new derived<U>();
                    data.reset(d);
                }

                return d->item;
            }

            any& operator= (
                const any& item
            )
            {
                any(item).swap(*this);
                return *this;
            }

            void swap (
                any& item
            )
            {
                data.swap(item.data);
            }

        private:

            struct base
            {
                virtual ~base() {}

                virtual void copy_to (
                    scoped_ptr<base>& dest
                ) const = 0;
            };

            template <typename T>
            struct derived : public base
            {
                T item;
                derived() {}
                derived(const T& val) : item(val) {}

                virtual void copy_to (
                    scoped_ptr<base>& dest
                ) const
                {
                    dest.reset(new derived<T>(item));
                }
            };

            scoped_ptr<base> data;
        };

    // ----------------------------------------------------------------------------------------

        inline void swap (
            any& a,
            any& b
        ) { a.swap(b); }

    // ----------------------------------------------------------------------------------------

        template <typename T> T& any_cast(any& a) { return a.cast_to<T>(); }
        template <typename T> const T& any_cast(const any& a) { return a.cast_to<T>(); }

    // ----------------------------------------------------------------------------------------

    }

    #endif // DLIB_AnY_H_