rom/utility/unpackstructuretags.c

   1 /*
   2     Copyright © 1995-2007, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: UnpackStructureTags - unpack structure to values in TagList.
   6     Lang: english
   7 */
   8 #include "intern.h"
   9
  10 /*****************************************************************************
  11
  12     NAME */
  13 #include <utility/tagitem.h>
  14 #include <utility/pack.h>
  15 #include <proto/utility.h>
  16
  17         AROS_LH3(ULONG, UnpackStructureTags,
  18
  19 /*  SYNOPSIS */
  20         AROS_LHA(APTR            , pack, A0),
  21         AROS_LHA(ULONG          *, packTable, A1),
  22         AROS_LHA(struct TagItem *, tagList, A2),
  23
  24 /*  LOCATION */
  25         struct Library *, UtilityBase, 36, Utility)
  26
  27 /*  FUNCTION
  28         For each table entry, if the matching tag is found in the tagList,
  29         then the data in the structure will be placed in the memory pointed
  30         to by the tags ti_Data.
  31
  32         Note: The value contained in ti_Data must be a *POINTER* to a
  33               IPTR.
  34
  35     INPUTS
  36         pack            -   Pointer to the memory area to be unpacked.
  37         packTable       -   Table describing the unpacking operation.
  38                             See the include file <utility/pack.h> for
  39                             more information on this table.
  40         tagList         -   List of TagItems to unpack into.
  41
  42     RESULT
  43         The number of Tags unpacked.
  44
  45     NOTES
  46         PSTF_EXISTS has no effect on this function.
  47
  48     EXAMPLE
  49
  50     BUGS
  51
  52     SEE ALSO
  53         PackStructureTags(), FindTagItem()
  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     Tag                 tagBase;
  66     UWORD               memOff;
  67     UWORD               tagOff;
  68     UBYTE               bitOff;
  69     struct TagItem *    ti;
  70     LONG                count = 0;
  71     union memaccess *   memptr;
  72
  73     tagBase = *packTable++;
  74     for( ; *packTable != 0; packTable++)
  75     {
  76         /* New base tag */
  77         if(*packTable == -1)
  78         {
  79             tagBase = *++packTable;
  80             continue;
  81         }
  82
  83         /* This entry is not defined for unpacking */
  84         if((*packTable & PSTF_UNPACK))    continue;
  85
  86         tagOff = (*packTable >> 16) & 0x3FF;
  87
  88         /* Does the tag we are interested in exist in that list. */
  89         ti = FindTagItem(tagBase + tagOff, tagList);
  90         if(ti == NULL)
  91             continue;
  92
  93         memOff = *packTable & 0x1FFF;
  94         bitOff = (*packTable & 0xE000) >> 13;
  95         memptr = (union memaccess *)((UBYTE *)pack + memOff);
  96
  97         /*
  98             The assigning is different for signed and unsigned since
  99             ti_Data is not necessarily the same size as the structure field,
 100             so we have to let the compiler do sign extension.
 101         */
 102         switch(*packTable & 0x98000000)
 103         {
 104             case PKCTRL_ULONG:
 105                 *(IPTR *)ti->ti_Data = (IPTR)memptr->ul;
 106                 break;
 107
 108             case PKCTRL_UWORD:
 109                 *(IPTR *)ti->ti_Data = (IPTR)memptr->uw;
 110                 break;
 111
 112             case PKCTRL_UBYTE:
 113                 *(IPTR *)ti->ti_Data = (IPTR)memptr->ub;
 114                 break;
 115
 116             case PKCTRL_LONG:
 117                 *(IPTR *)ti->ti_Data = (IPTR)memptr->sl;
 118                 break;
 119
 120             case PKCTRL_WORD:
 121                 *(IPTR *)ti->ti_Data = (IPTR)memptr->sw;
 122                 break;
 123
 124             case PKCTRL_BYTE:
 125                 *(IPTR *)ti->ti_Data = (IPTR)memptr->sb;
 126                 break;
 127
 128             case PKCTRL_BIT:
 129                 if( memptr->ub & (1 << bitOff) )
 130                     *(IPTR *)ti->ti_Data = TRUE;
 131                 else
 132                     *(IPTR *)ti->ti_Data = FALSE;
 133                 break;
 134
 135             case PKCTRL_FLIPBIT:
 136                 if( memptr->ub & (1 << bitOff) )
 137                     *(IPTR *)ti->ti_Data = FALSE;
 138                 else
 139                     *(IPTR *)ti->ti_Data = TRUE;
 140                 break;
 141
 142             /* We didn't actually pack anything */
 143             default:
 144                 count--;
 145
 146         } /* switch() */
 147
 148         count++;
 149
 150     } /* for() */
 151
 152     return count;
 153
 154     AROS_LIBFUNC_EXIT
 155 } /* UnpackStructureTags */