![[Contents]](../images/toc_d.gif)
![[Index]](../images/index_d.gif)
![[Help]](../images/help_d.gif)
![[Retrace]](../images/retrace_d.gif)
![[Browse <]](../images/prev.gif)
![[Browse >]](../images/next.gif)
;/* RKMModel.c - A simple custom modelclass subclass.
LC -cfist -b1 -y -v -j73 rkmmodel.c
quit ;*/
#include <exec/types.h>
#include <intuition/intuition.h>
#include <intuition/classes.h>
#include <intuition/classusr.h>
#include <intuition/imageclass.h>
#include <intuition/gadgetclass.h>
#include <intuition/cghooks.h>
#include <intuition/icclass.h>
#include <utility/tagitem.h>
#include <utility/hooks.h>
#include <clib/intuition_protos.h>
#include <clib/utility_protos.h>
#include <clib/alib_protos.h>
#include <clib/alib_stdio_protos.h>
extern struct Library *IntuitionBase, *UtilityBase;
/*************************************************************************************************/
/**************** The attributes defined by this class *****************************************/
/*************************************************************************************************/
#define RKMMOD_CurrVal (TAG_USER + 1) /* This attribute is the current value of the model.*******/
/**********************************************************/
#define RKMMOD_Up (TAG_USER + 2) /* These two are fake attributes that rkmmodelclass *******/
#define RKMMOD_Down (TAG_USER + 3) /* uses as pulse values to increment/decrement the *******/
/* rkmmodel's RKMMOD_CurrVal attribute. *******/
/**********************************************************/
#define RKMMOD_Limit (TAG_USER + 4) /* This attribute contains the upper bound of the *******/
/* rkmmodel's RKMMOD_CurrVal. The rkmmodel has a *******/
/* static lower bound of zero. *******/
/*************************************************************************************************/
#define DEFAULTVALLIMIT 100L /* If the programmer doesn't set */
/* RKMMOD_Limit, it defaults to this. */
struct RKMModData {
ULONG currval; /* The instance data for this class. */
ULONG vallimit;
};
/*************************************************************************************************/
/************************** The functions in this module ********************************/
/*************************************************************************************************/
void geta4(void); /***************/
Class *initRKMModClass(void); /***************/
BOOL freeRKMModClass(Class *); /***************/
ULONG dispatchRKMModel(Class *, Object *, Msg); /***************/
void NotifyCurrVal(Class *, Object *, struct opUpdate *, struct RKMModData *); /***************/
/*************************************************************************************************/
/*************************************************************************************************/
/******************************** Initialize the class **************************************/
/*************************************************************************************************/
Class *initRKMModClass(void) /* Make the class and set */
{ /* up the dispatcher's hook. */
Class *cl;
extern ULONG HookEntry(); /* <------- defined in amiga.lib. */
if ( cl = MakeClass( NULL,
"modelclass", NULL,
sizeof ( struct RKMModData ),
0 ))
{
cl->cl_Dispatcher.h_Entry = HookEntry; /* initialize the */
cl->cl_Dispatcher.h_SubEntry = dispatchRKMModel; /* cl_Dispatcher */
/* Hook. */
}
return ( cl );
}
/*************************************************************************************************/
/********************************* Free the class ***************************************/
/*************************************************************************************************/
BOOL freeRKMModClass( Class *cl )
{
return (FreeClass(cl));
}
/*************************************************************************************************/
/******************************** The class Dispatcher ***********************************/
/*************************************************************************************************/
ULONG dispatchRKMModel(Class *cl, Object *o, Msg msg)
{
struct RKMModData *mmd;
APTR retval = NULL; /* A generic return value used by this class's methods. The */
/* meaning of this field depends on the method. For example, */
/* OM_GET uses this a a boolean return value, while OM_NEW */
/* uses it as a pointer to the new object. */
geta4(); /* SAS/C and Manx function - makes sure A4 contains global data pointer. */
switch (msg->MethodID)
{
case OM_NEW: /* Pass message onto superclass first so it can set aside the memory */
/* for the object and take care of superclass instance data. */
if (retval = (APTR)DoSuperMethodA(cl, o, msg))
{ /************************************************************************/
/* For the OM_NEW method, the object pointer passed to the dispatcher */
/* does not point to an object (how could it? The object doesn't exist */
/* yet.) DoSuperMethodA() returns a pointer to a newly created */
/* object. INST_DATA() is a macro defined in <intuition/classes.h> */
/* that returns a pointer to the object's instance data that is local */
/* to this class. For example, the instance data local to this class */
/* is the RKMModData structure defined above. */
/************************************************************************/
mmd = INST_DATA(cl, retval);
mmd->currval = GetTagData(RKMMOD_CurrVal, 0L, /* initialize object's attributes. */
((struct opSet *)msg)->ops_AttrList);
mmd->vallimit = GetTagData(RKMMOD_Limit, DEFAULTVALLIMIT,
((struct opSet *)msg)->ops_AttrList);
}
break;
case OM_SET:
case OM_UPDATE:
mmd = INST_DATA(cl, o);
DoSuperMethodA(cl, o, msg); /* Let the superclasses set their attributes first. */
{
struct TagItem *tstate, *ti; /* grab some temp variables off of the stack. */
ti = ((struct opSet *)msg)->ops_AttrList;
tstate = ti;
/* Step through all of the attribute/value pairs in the list. Use the */
/* utility.library tag functions to do this so they can properly process */
/* special tag IDs like TAG_SKIP, TAG_IGNORE, etc. */
while (ti = NextTagItem(&tstate)) /* Step through all of the attribute/value */
{ /* pairs in the list. Use the utility.library tag functions */
/* to do this so they can properly process special tag IDs */
/* like TAG_SKIP, TAG_IGNORE, etc. */
switch (ti->ti_Tag)
{
case RKMMOD_CurrVal:
if ((ti->ti_Data) > mmd->vallimit) ti->ti_Data =
mmd->vallimit;
mmd->currval = ti->ti_Data;
NotifyCurrVal(cl, o, msg, mmd);
retval = (APTR)1L; /* Changing RKMMOD_CurrVal can cause a visual */
break; /* change to gadgets in the rkmmodel's broadcast */
/* list. The rkmmodel has to tell the applica- */
/* tion by returning a value besides zero. */
case RKMMOD_Up:
mmd->currval++;
/* Make sure the current value is not greater than value limit. */
if ((mmd->currval) > mmd->vallimit) mmd->currval = mmd->vallimit;
NotifyCurrVal(cl, o, msg, mmd);
retval = (APTR)1L; /* Changing RKMMOD_Up can cause a visual */
break; /* change to gadgets in the rkmmodel's broadcast */
/* list. The rkmmodel has to tell the applica- */
/* tion by returning a value besides zero. */
case RKMMOD_Down:
mmd->currval--;
/* Make sure currval didn't go negative. */
if ((LONG)(mmd->currval) == -1L)
mmd->currval = 0L;
NotifyCurrVal(cl, o, msg, mmd);
retval = (APTR)1L; /* Changing RKMMOD_Down can cause a visual */
break; /* change to gadgets in the rkmmodel's broadcast */
/* list. The rkmmodel has to tell the applica- */
/* tion by returning a value besides zero. */
case RKMMOD_Limit:
mmd->vallimit = ti->ti_Data; /* Set the limit. Note that this does */
break; /* not do bounds checking on the */
/* current RKMModData.currval value. */
}
}
}
break;
case OM_GET: /* The only attribute that is "gettable" in this */
mmd = INST_DATA(cl, o); /* class or its superclasses is RKMMOD_CurrVal. */
if ((((struct opGet *)msg)->opg_AttrID) == RKMMOD_CurrVal)
{
*(((struct opGet *)msg)->opg_Storage) = mmd->currval;
retval = (Object *)TRUE;
}
else retval = (APTR)DoSuperMethodA(cl, o, msg);
break;
default: /* rkmmodelclass does not recognize the methodID, so let the superclass's */
/* dispatcher take a look at it. */
retval = (APTR)DoSuperMethodA(cl, o, msg);
break;
}
return((ULONG)retval);
}
void NotifyCurrVal(Class *cl, Object *o, struct opUpdate *msg, struct RKMModData *mmd)
{
struct TagItem tt[2];
tt[0].ti_Tag = RKMMOD_CurrVal; /* make a tag list. */
tt[0].ti_Data = mmd->currval;
tt[1].ti_Tag = TAG_DONE;
/* If the RKMMOD_CurrVal changes, we want everyone to know about */
DoSuperMethod(cl, o, /* it. Theoretically, the class is supposed to send itself a */
OM_NOTIFY, /* OM_NOTIFY message. Because this class lets its superclass */
tt, /* handle the OM_NOTIFY message, it skips the middleman and */
msg->opu_GInfo, /* sends the OM_NOTIFY directly to its superclass. */
((msg->MethodID == OM_UPDATE) ? (msg->opu_Flags) : 0L)); /* If this is an OM_UPDATE */
/* method, make sure the part the OM_UPDATE message adds to the */
/* OM_SET message gets added. That lets the dispatcher handle */
} /* OM_UPDATE and OM_SET in the same case. */
[Back to Amiga Developer Docs]