rom/intuition/nextobject.c

   1 /*
   2     Copyright © 1995-2003, The AROS Development Team. All rights reserved.
   3     Copyright © 2001-2003, The MorphOS Development Team. All Rights Reserved.
   4     $Id$
   5
   6     Iterate through a list of objects.
   7 */
   8
   9 #include <exec/types.h>
  10 #include <exec/nodes.h>
  11 #include "intuition_intern.h"
  12
  13 /*****************************************************************************
  14
  15     NAME */
  16 #include <intuition/classes.h>
  17 #include <proto/intuition.h>
  18
  19 AROS_LH1(APTR, NextObject,
  20
  21          /*  SYNOPSIS */
  22          AROS_LHA(APTR, objectPtrPtr, A0),
  23
  24          /*  LOCATION */
  25          struct IntuitionBase *, IntuitionBase, 111, Intuition)
  26
  27 /*  FUNCTION
  28     Use this function to iterate through a list of BOOPSI objects.
  29     You may do whatever you want with the object returned, even
  30     remove it from the list or disposing it and then continue to
  31     iterate thought the list.
  32
  33     INPUTS
  34     objectPtrPtr - the pointer to a variable. This must be the same
  35         variable, as long as you iterate though the same list. This
  36         variable must initially be filled with the lh_Head of a list.
  37
  38     RESULT
  39     A BOOPSI object, which can be manipulated.
  40
  41     NOTES
  42
  43     EXAMPLE
  44
  45     BUGS
  46
  47     SEE ALSO
  48     NewObject(),
  49     "Basic Object-Oriented Programming System for Intuition" and
  50     "boopsi Class Reference" Dokument.
  51
  52     INTERNALS
  53
  54     HISTORY
  55
  56 *****************************************************************************/
  57 {
  58     AROS_LIBFUNC_INIT
  59     AROS_LIBBASE_EXT_DECL(struct IntuitionBase *,IntuitionBase)
  60
  61     struct _Object *nextobject;
  62     APTR            oldobject;
  63
  64     DEBUG_NEXTOBJECT(dprintf("NextObject: optr 0x%lx\n",
  65                              objectPtrPtr));
  66
  67     IntuitionBase = IntuitionBase;  /* shut up the compiler */
  68
  69     SANITY_CHECKR(objectPtrPtr,FALSE)
  70
  71     nextobject = (struct _Object *)(*((struct _Object **)objectPtrPtr))->o_Node.mln_Succ;
  72     if (nextobject)
  73     {
  74         oldobject = (Object *)BASEOBJECT(*((struct _Object **)objectPtrPtr));
  75         *((struct _Object **)objectPtrPtr) = nextobject;
  76     }
  77     else
  78     {
  79         oldobject = NULL;
  80     }
  81
  82     return oldobject;
  83
  84     AROS_LIBFUNC_EXIT
  85 } /* NextObject() */