rom/utility/filtertagchanges.c

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: FilterTagChanges() - filter unchanged tags from a list.
   6     Lang: english
   7 */
   8 #include "intern.h"
   9
  10 /*****************************************************************************
  11
  12     NAME */
  13 #include <proto/utility.h>
  14
  15         AROS_LH3(void, FilterTagChanges,
  16
  17 /*  SYNOPSIS */
  18         AROS_LHA(struct TagItem *      , changeList, A0),
  19         AROS_LHA(const struct TagItem *, originalList, A1),
  20         AROS_LHA(BOOL                  , apply, D0),
  21
  22 /*  LOCATION */
  23         struct Library *, UtilityBase, 9, Utility)
  24
  25 /*  FUNCTION
  26         This function will scan through changeList, and if an item in
  27         changeList exists in originalList, but both items data values
  28         are equal, then the item in changeList will be removed from the
  29         list.
  30
  31         If the value of apply is TRUE, then if the datas are different
  32         then the values in originalList will be updated to match those
  33         in changeList.
  34
  35     INPUTS
  36         changeList      -   List of new tags (may be NULL).
  37         originalList    -   List of existing tags (may be NULL).
  38         apply           -   Boolean flag as to whether the values in
  39                             originalList should be updated to match
  40                             those in changeList.
  41
  42     RESULT
  43         The changeList will be modified to show altered items, and if
  44         requested, the originalList will be updated.
  45
  46     NOTES
  47
  48     EXAMPLE
  49
  50     BUGS
  51
  52     SEE ALSO
  53         ApplyTagChanges()
  54
  55     INTERNALS
  56
  57     HISTORY
  58         29-10-95    digulla automatically created from
  59                             utility_lib.fd and clib/utility_protos.h
  60
  61 *****************************************************************************/
  62 {
  63     AROS_LIBFUNC_INIT
  64
  65     if (originalList && changeList)
  66     {
  67         struct TagItem *change, *orig;
  68
  69         while ((change = NextTagItem(&changeList)))
  70         {
  71             if ((orig = FindTagItem(change->ti_Tag, originalList)))
  72             {
  73                 if (change->ti_Data == orig->ti_Data)
  74                 {
  75                     change->ti_Tag = TAG_IGNORE;
  76                 }
  77                 else
  78                 {
  79                     if (apply)
  80                         orig->ti_Data = change->ti_Data;
  81                 }
  82             } /* if (FindTagItem()) */
  83         } /* while (changeList++) */
  84     } /* if (lists are both valid) */
  85
  86     AROS_LIBFUNC_EXIT
  87 } /* FilterTagChanges */