#ifndef INTUITION_CLASSES_H
#define INTUITION_CLASSES_H     1
/*
**  $Filename: intuition/classes.h $
**  $Release: 2.04 Includes, V37.4 $
**  $Revision: 36.2 $
**  $Date: 91/11/08 $
**
**  Used only by class implementors
**
**  (C) Copyright 1989-1999 Amiga, Inc.
**          All Rights Reserved
*/

#ifndef UTILITY_HOOKS_H
#include <utility/hooks.h>
#endif

#ifndef INTUITION_CLASSUSR_H
#include <intuition/classusr.h>
#endif

/*******************************************/
/*** "White box" access to struct IClass ***/
/*******************************************/

/* This structure is READ-ONLY, and allocated only by Intuition */
typedef struct IClass {
    struct Hook                cl_Dispatcher;
    ULONG              cl_Reserved;    /* must be 0  */
    struct IClass      *cl_Super;
    ClassID             cl_ID;

    /* where within an object is the instance data for this class? */
    UWORD              cl_InstOffset;
    UWORD               cl_InstSize;

    ULONG              cl_UserData;    /* per-class data of your choice */
    ULONG               cl_SubclassCount;
                                       /* how many direct subclasses?  */
    ULONG               cl_ObjectCount;
                               /* how many objects created of this class? */
    ULONG              cl_Flags;
#define        CLF_INLIST      0x00000001      /* class is in public class list */
} Class;

/* add offset for instance data to an object handle */
#define INST_DATA( cl, o )      ((VOID *) (((UBYTE *)o)+cl->cl_InstOffset))

/* sizeof the instance data for a given class */
#define SIZEOF_INSTANCE( cl )  ((cl)->cl_InstOffset + (cl)->cl_InstSize \
                        + sizeof (struct _Object ))

/**************************************************/
/*** "White box" access to struct _Object     ***/
/**************************************************/

/*
 * We have this, the instance data of the root class, PRECEDING
 * the "object".  This is so that Gadget objects are Gadget pointers,
 * and so on.  If this structure grows, it will always have o_Class
 * at the end, so the macro OCLASS(o) will always have the same
 * offset back from the pointer returned from NewObject().
 *
 * This data structure is subject to change.  Do not use the o_Node
 * embedded structure.
 */
struct _Object {
    struct MinNode     o_Node;
    struct IClass       *o_Class;
};

/* convenient typecast */
#define _OBJ( o )       ((struct _Object *)(o))

/* get "public" handle on baseclass instance from real beginning of obj data */
#define BASEOBJECT( _obj )      ( (Object *) (_OBJ(_obj)+1) )

/* get back to object data struct from public handle */
#define _OBJECT( o )            (_OBJ(o) - 1)

/* get class pointer from an object handle     */
#define OCLASS( o )     ( (_OBJECT(o))->o_Class )

#endif