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

    #include "any.h"
    #include "../smart_pointers.h"

    #include "any_decision_function_abstract.h"

    namespace dlib
    {

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

        template <
            typename sample_type_,
            typename result_type_ = double
            >
        class any_decision_function
        {

        public:

            typedef sample_type_ sample_type;
            typedef result_type_ result_type;
            typedef default_memory_manager mem_manager_type;

            any_decision_function()
            {
            }

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

            template <typename T>
            any_decision_function (
                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;
            }

            result_type operator() (
                const sample_type& item
            ) const
            {
                // make sure requires clause is not broken
                DLIB_ASSERT(is_empty() == false,
                    "\t result_type any_decision_function::operator()"
                    << "\n\t You can't call operator() on an empty any_decision_function"
                    << "\n\t this: " << this
                    );

                return data->evaluate(item);
            }

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

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

        private:

            struct base
            {
                virtual ~base() {}

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

                virtual result_type evaluate (
                    const sample_type& samp
                ) 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));
                }

                virtual result_type evaluate (
                    const sample_type& samp
                ) const
                {
                    return item(samp);
                }
            };

            scoped_ptr<base> data;
        };

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

        template <
            typename sample_type,
            typename result_type
            >
        inline void swap (
            any_decision_function<sample_type, result_type>& a,
            any_decision_function<sample_type, result_type>& b
        ) { a.swap(b); }

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

        template <typename T, typename U, typename V>
        T& any_cast(any_decision_function<U,V>& a) { return a.template cast_to<T>(); }

        template <typename T, typename U, typename V>
        const T& any_cast(const any_decision_function<U,V>& a) { return a.template cast_to<T>(); }

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

    }

    #endif // DLIB_AnY_DECISION_FUNCTION_H__