rom/intuition/nextobject.c

   1 /*
   2     Copyright © 1995-2013, 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 dispose it, and then continue to
  31         iterate through 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         NewObjectA(),
  49         "Basic Object-Oriented Programming System for Intuition" and
  50         "Boopsi Class Reference" Document.
  51
  52     INTERNALS
  53
  54 *****************************************************************************/
  55 {
  56     AROS_LIBFUNC_INIT
  57
  58     struct _Object *nextobject;
  59     APTR            oldobject;
  60
  61     DEBUG_NEXTOBJECT(dprintf("NextObject: optr 0x%lx\n",
  62                              objectPtrPtr));
  63
  64     IntuitionBase = IntuitionBase;  /* shut up the compiler */
  65
  66     SANITY_CHECKR(objectPtrPtr,FALSE)
  67
  68     nextobject = (struct _Object *)(*((struct _Object **)objectPtrPtr))->o_Node.mln_Succ;
  69     if (nextobject)
  70     {
  71         oldobject = (Object *)BASEOBJECT(*((struct _Object **)objectPtrPtr));
  72         *((struct _Object **)objectPtrPtr) = nextobject;
  73     }
  74     else
  75     {
  76         oldobject = NULL;
  77     }
  78
  79     return oldobject;
  80
  81     AROS_LIBFUNC_EXIT
  82 } /* NextObject() */