dlib C++ Library - member_function_pointer_kernel_1.h

    // Copyright (C) 2005  Davis E. King (davisking@users.sourceforge.net)
    // License: Boost Software License   See LICENSE.txt for the full license.
    #ifndef DLIB_MEMBER_FUNCTION_POINTER_KERNEl_1_
    #define DLIB_MEMBER_FUNCTION_POINTER_KERNEl_1_

    #include "../algs.h"
    #include "member_function_pointer_kernel_abstract.h"
    #include "../enable_if.h"
    #include <new>

    namespace dlib
    {

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

        template <
            typename PARAM1 = void,
            typename PARAM2 = void,
            typename PARAM3 = void,
            typename PARAM4 = void
            >
        class mfpk1;

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

        template <unsigned long num_args>
        class mfp_kernel_1_base_class
        {
            /*
                All member function pointer classes inherit from this class.  This
                is where most of the things in a member function pointer are defined.

                The reason for the num_args template argument to this class is to prevent
                any sort of implicit casting between derived member function pointer classes
                that take different numbers of arguments.
            */
        protected:
            enum mfp_type { mfp_nonconst, mfp_const, mfp_null};

            class mp_base_base
            {
            public:
                mp_base_base(void* ptr, mfp_type type_) : o(ptr),type(type_) {}
                virtual ~mp_base_base(){}
                virtual void clone(void* ptr) const = 0;
                virtual bool is_same (const mp_base_base* item) const = 0;
                bool is_set () const { return o!=0; }

                void* const o;
                const mfp_type type;
            };

            template <typename T>
            class mp_null : public mp_base_base
            {
            public:
                typedef void (T::*mfp_pointer_type)() ;

                mp_null (void* , mfp_pointer_type ) : mp_base_base(0,mfp_null), callback(0) {}
                mp_null () : mp_base_base(0,mfp_null), callback(0) {}

                const mfp_pointer_type callback;
            };

            template <typename mp_impl>
            class mp_impl_T : public mp_impl
            {
                /*
                    This class supplies the implementations clone() and is_same() for any
                    classes that inherit from mp_base_base.  It does this in a very
                    roundabout way...
                */

            public:
                typedef typename mp_impl::mfp_pointer_type mfp_pointer_type;

                mp_impl_T() : mp_impl(0,0) {}
                mp_impl_T(void* ptr, mfp_pointer_type cb) : mp_impl(ptr,cb) {}

                template <unsigned long mem_size>
                void safe_clone(char (&buf)[mem_size])
                {
                    // This is here just to validate the assumption that our block of memory we have made
                    // in mp_memory.data is the right size to store the data for this object.  If you
                    // get a compiler error on this line then email me :)
                    COMPILE_TIME_ASSERT(sizeof(mp_impl_T) <= mem_size);
                    clone(buf);
                }

                void clone   (void* ptr) const  { new(ptr) mp_impl_T(this->o,this->callback); }
                bool is_same (const mp_base_base* item) const
                {
                    if (item->o == 0 && this->o == 0)
                    {
                        return true;
                    }
                    else if (item->o == this->o && this->type == item->type)
                    {
                        const mp_impl* i = reinterpret_cast<const mp_impl*>(item);
                        return (i->callback == this->callback);
                    }
                    return false;
                }
            };

            struct dummy_base { virtual void nonnull() {}; int a; };
            struct dummy : virtual public dummy_base{ void nonnull() {}; };

            typedef mp_impl_T<mp_null<dummy> > mp_null_impl;
        public:

            mfp_kernel_1_base_class (
                const mfp_kernel_1_base_class& item
            ) { item.mp()->clone(mp_memory.data); }

            mfp_kernel_1_base_class (
            ) { mp_null_impl().safe_clone(mp_memory.data); }

            bool operator == (
                const mfp_kernel_1_base_class& item
            ) const { return mp()->is_same(item.mp()); }

            bool operator != (
                const mfp_kernel_1_base_class& item
            ) const { return !(*this == item); }

            mfp_kernel_1_base_class& operator= (
                const mfp_kernel_1_base_class& item
            ) { mfp_kernel_1_base_class(item).swap(*this); return *this;  }

            ~mfp_kernel_1_base_class (
            ) { destroy_mp_memory(); }

            void clear(
            ) { mfp_kernel_1_base_class().swap(*this); }

            bool is_set (
            ) const { return mp()->is_set(); }

        private:
            typedef void (dummy::*safe_bool)();

        public:
            operator safe_bool () const { return is_set() ? &dummy::nonnull : 0; }
            bool operator!() const { return !is_set(); }

            void swap (
                mfp_kernel_1_base_class& item
            )
            {
                // make a temp copy of item
                mfp_kernel_1_base_class temp(item);

                // destory the stuff in item
                item.destroy_mp_memory();
                // copy *this into item
                mp()->clone(item.mp_memory.data);

                // destory the stuff in this
                destroy_mp_memory();
                // copy temp into *this
                temp.mp()->clone(mp_memory.data);
            }

        protected:

            // make a block of memory big enough to hold a mp_null object.
            union data_block_type
            {
                // All of this garbage is to make sure this union is properly aligned
                // (a union is always aligned such that everything in it would be properly
                // aligned.  So the assumption here is that one of these things big good
                // alignment to satisfy mp_null_impl objects (or other objects like it).
                void* void_ptr;
                struct {
                    void (mp_base_base::*callback)();
                    mp_base_base* o;
                } stuff;

                char data[sizeof(mp_null_impl)];
            } mp_memory;

            void destroy_mp_memory (
            )
            {
                // Honestly this probably doesn't even do anything but I'm putting
                // it here just for good measure.
                mp()->~mp_base_base();
            }

            mp_base_base*       mp ()       { void* ptr = mp_memory.data;       return static_cast<mp_base_base*>(ptr); }
            const mp_base_base* mp () const { const void* ptr = mp_memory.data; return static_cast<const mp_base_base*>(ptr); }

        };

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

        template <>
        class mfpk1<void,void,void,void> : public mfp_kernel_1_base_class<0>
        {
            class mp_base : public mp_base_base {
            public:
                mp_base(void* ptr, mfp_type type_) : mp_base_base(ptr,type_) {}
                virtual void call() const = 0;
            };

            template <typename T>
            class mp_impl : public mp_base {
            public:
                typedef void (T::*mfp_pointer_type)() ;
                void call () const { (static_cast<T*>(this->o)->*callback)(); }

                mp_impl      ( void* object, mfp_pointer_type cb) : mp_base(object, mfp_nonconst), callback(cb) {}
                const mfp_pointer_type callback;
            };

            template <typename T>
            class mp_impl_const : public mp_base {
            public:
                typedef void ((T::*mfp_pointer_type)()const);
                void call () const  { (static_cast<const T*>(this->o)->*callback)(); }

                mp_impl_const ( void* object, mfp_pointer_type cb) : mp_base(object,mfp_const), callback(cb) {}
                const mfp_pointer_type callback;
            };

        public:
            typedef void param1_type;
            typedef void param2_type;
            typedef void param3_type;
            typedef void param4_type;

            void operator() () const { static_cast<const mp_base*>((const void*)mp_memory.data)->call(); }

            // the reason for putting disable_if on this function is that it avoids an overload
            // resolution bug in visual studio.
            template <typename T> typename disable_if<is_const_type<T>,void>::type
            set(T& object, typename mp_impl<T>::mfp_pointer_type cb)
            { destroy_mp_memory(); mp_impl_T<mp_impl<T> >(&object,cb).safe_clone(mp_memory.data); }

            template <typename T> void set(const T& object, typename mp_impl_const<T>::mfp_pointer_type cb)
            { destroy_mp_memory(); mp_impl_T<mp_impl_const<T> >((void*)&object,cb).safe_clone(mp_memory.data); }

        };

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

        template <
            typename PARAM1
            >
        class mfpk1<PARAM1,void,void,void> : public mfp_kernel_1_base_class<1>
        {
            class mp_base : public mp_base_base {
            public:
                mp_base(void* ptr, mfp_type type_) : mp_base_base(ptr,type_) {}
                virtual void call(PARAM1) const = 0;
            };

            template <typename T>
            class mp_impl : public mp_base {
            public:
                typedef void (T::*mfp_pointer_type)(PARAM1) ;
                void call (PARAM1 p1) const { (static_cast<T*>(this->o)->*callback)(p1); }

                mp_impl      ( void* object, mfp_pointer_type cb) : mp_base(object, mfp_nonconst), callback(cb) {}
                const mfp_pointer_type callback;
            };

            template <typename T>
            class mp_impl_const : public mp_base {
            public:
                typedef void ((T::*mfp_pointer_type)(PARAM1)const);
                void call (PARAM1 p1) const  { (static_cast<const T*>(this->o)->*callback)(p1); }

                mp_impl_const ( void* object, mfp_pointer_type cb) : mp_base(object,mfp_const), callback(cb) {}
                const mfp_pointer_type callback;
            };

        public:
            typedef PARAM1 param1_type;
            typedef void param2_type;
            typedef void param3_type;
            typedef void param4_type;

            void operator() (PARAM1 p1) const { static_cast<const mp_base*>((const void*)mp_memory.data)->call(p1); }

            // the reason for putting disable_if on this function is that it avoids an overload
            // resolution bug in visual studio.
            template <typename T> typename disable_if<is_const_type<T>,void>::type
            set(T& object, typename mp_impl<T>::mfp_pointer_type cb)
            { destroy_mp_memory(); mp_impl_T<mp_impl<T> >(&object,cb).safe_clone(mp_memory.data); }

            template <typename T> void set(const T& object, typename mp_impl_const<T>::mfp_pointer_type cb)
            { destroy_mp_memory(); mp_impl_T<mp_impl_const<T> >((void*)&object,cb).safe_clone(mp_memory.data); }

        };

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

        template <
            typename PARAM1,
            typename PARAM2
            >
        class mfpk1<PARAM1,PARAM2,void,void> : public mfp_kernel_1_base_class<2>
        {
            class mp_base : public mp_base_base {
            public:
                mp_base(void* ptr, mfp_type type_) : mp_base_base(ptr,type_) {}
                virtual void call(PARAM1,PARAM2) const = 0;
            };

            template <typename T>
            class mp_impl : public mp_base {
            public:
                typedef void (T::*mfp_pointer_type)(PARAM1,PARAM2) ;
                void call (PARAM1 p1, PARAM2 p2) const { (static_cast<T*>(this->o)->*callback)(p1,p2); }

                mp_impl      ( void* object, mfp_pointer_type cb) : mp_base(object, mfp_nonconst), callback(cb) {}
                const mfp_pointer_type callback;
            };

            template <typename T>
            class mp_impl_const : public mp_base {
            public:
                typedef void ((T::*mfp_pointer_type)(PARAM1,PARAM2)const);
                void call (PARAM1 p1, PARAM2 p2) const  { (static_cast<const T*>(this->o)->*callback)(p1,p2); }

                mp_impl_const ( void* object, mfp_pointer_type cb) : mp_base(object,mfp_const), callback(cb) {}
                const mfp_pointer_type callback;
            };

        public:
            typedef PARAM1 param1_type;
            typedef PARAM2 param2_type;
            typedef void param3_type;
            typedef void param4_type;

            void operator() (PARAM1 p1, PARAM2 p2) const { static_cast<const mp_base*>((const void*)mp_memory.data)->call(p1,p2); }

            // the reason for putting disable_if on this function is that it avoids an overload
            // resolution bug in visual studio.
            template <typename T> typename disable_if<is_const_type<T>,void>::type
            set(T& object, typename mp_impl<T>::mfp_pointer_type cb)
            { destroy_mp_memory(); mp_impl_T<mp_impl<T> >(&object,cb).safe_clone(mp_memory.data); }

            template <typename T> void set(const T& object, typename mp_impl_const<T>::mfp_pointer_type cb)
            { destroy_mp_memory(); mp_impl_T<mp_impl_const<T> >((void*)&object,cb).safe_clone(mp_memory.data); }

        };

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

        template <
            typename PARAM1,
            typename PARAM2,
            typename PARAM3
            >
        class mfpk1<PARAM1,PARAM2,PARAM3,void> : public mfp_kernel_1_base_class<3>
        {
            class mp_base : public mp_base_base {
            public:
                mp_base(void* ptr, mfp_type type_) : mp_base_base(ptr,type_) {}
                virtual void call(PARAM1,PARAM2,PARAM3) const = 0;
            };

            template <typename T>
            class mp_impl : public mp_base {
            public:
                typedef void (T::*mfp_pointer_type)(PARAM1,PARAM2,PARAM3) ;
                void call (PARAM1 p1, PARAM2 p2, PARAM3 p3) const { (static_cast<T*>(this->o)->*callback)(p1,p2,p3); }

                mp_impl      ( void* object, mfp_pointer_type cb) : mp_base(object, mfp_nonconst), callback(cb) {}
                const mfp_pointer_type callback;
            };

            template <typename T>
            class mp_impl_const : public mp_base {
            public:
                typedef void ((T::*mfp_pointer_type)(PARAM1,PARAM2,PARAM3)const);
                void call (PARAM1 p1, PARAM2 p2, PARAM3 p3) const  { (static_cast<const T*>(this->o)->*callback)(p1,p2,p3); }

                mp_impl_const ( void* object, mfp_pointer_type cb) : mp_base(object,mfp_const), callback(cb) {}
                const mfp_pointer_type callback;
            };

        public:
            typedef PARAM1 param1_type;
            typedef PARAM2 param2_type;
            typedef PARAM3 param3_type;
            typedef void param4_type;

            void operator() (PARAM1 p1, PARAM2 p2, PARAM3 p3) const { static_cast<const mp_base*>((const void*)mp_memory.data)->call(p1,p2,p3); }

            // the reason for putting disable_if on this function is that it avoids an overload
            // resolution bug in visual studio.
            template <typename T> typename disable_if<is_const_type<T>,void>::type
            set(T& object, typename mp_impl<T>::mfp_pointer_type cb)
            { destroy_mp_memory(); mp_impl_T<mp_impl<T> >(&object,cb).safe_clone(mp_memory.data); }

            template <typename T> void set(const T& object, typename mp_impl_const<T>::mfp_pointer_type cb)
            { destroy_mp_memory(); mp_impl_T<mp_impl_const<T> >((void*)&object,cb).safe_clone(mp_memory.data); }

        };

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

        template <
            typename PARAM1,
            typename PARAM2,
            typename PARAM3,
            typename PARAM4
            >
        class mfpk1 : public mfp_kernel_1_base_class<4>
        {
            class mp_base : public mp_base_base {
            public:
                mp_base(void* ptr, mfp_type type_) : mp_base_base(ptr,type_) {}
                virtual void call(PARAM1,PARAM2,PARAM3,PARAM4) const = 0;
            };

            template <typename T>
            class mp_impl : public mp_base {
            public:
                typedef void (T::*mfp_pointer_type)(PARAM1,PARAM2,PARAM3, PARAM4) ;
                void call (PARAM1 p1, PARAM2 p2, PARAM3 p3, PARAM4 p4) const { (static_cast<T*>(this->o)->*callback)(p1,p2,p3,p4); }

                mp_impl      ( void* object, mfp_pointer_type cb) : mp_base(object, mfp_nonconst), callback(cb) {}
                const mfp_pointer_type callback;
            };

            template <typename T>
            class mp_impl_const : public mp_base {
            public:
                typedef void ((T::*mfp_pointer_type)(PARAM1,PARAM2,PARAM3,PARAM4)const);
                void call (PARAM1 p1, PARAM2 p2, PARAM3 p3, PARAM4 p4) const  { (static_cast<const T*>(this->o)->*callback)(p1,p2,p3,p4); }

                mp_impl_const ( void* object, mfp_pointer_type cb) : mp_base(object,mfp_const), callback(cb) {}
                const mfp_pointer_type callback;
            };

        public:
            typedef PARAM1 param1_type;
            typedef PARAM2 param2_type;
            typedef PARAM3 param3_type;
            typedef PARAM4 param4_type;

            void operator() (PARAM1 p1, PARAM2 p2, PARAM3 p3, PARAM4 p4) const
            { static_cast<const mp_base*>((const void*)mp_memory.data)->call(p1,p2,p3,p4); }

            // the reason for putting disable_if on this function is that it avoids an overload
            // resolution bug in visual studio.
            template <typename T> typename disable_if<is_const_type<T>,void>::type
            set(T& object, typename mp_impl<T>::mfp_pointer_type cb)
            { destroy_mp_memory(); mp_impl_T<mp_impl<T> >(&object,cb).safe_clone(mp_memory.data); }

            template <typename T> void set(const T& object, typename mp_impl_const<T>::mfp_pointer_type cb)
            { destroy_mp_memory(); mp_impl_T<mp_impl_const<T> >((void*)&object,cb).safe_clone(mp_memory.data); }

        };

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

    }

    #endif // DLIB_MEMBER_FUNCTION_POINTER_KERNEl_1_