rom/dos/internalseek.c

   1 /*
   2     Copyright © 2002-2007, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6 #undef SDEBUG
   7 #undef DEBUG
   8 #define DEBUG 0
   9 #include <aros/debug.h>
  10
  11 #include <proto/dos.h>
  12 #include "dos_intern.h"
  13
  14 LONG InternalSeek
  15 (
  16     struct FileHandle *fh,
  17     LONG               position,
  18     LONG               mode,
  19     struct DosLibrary *DOSBase
  20 )
  21 {
  22
  23     /* Get pointer to I/O request. Use stackspace for now. */
  24     struct IOFileSys iofs;
  25
  26     /* Make sure the input parameters are sane. */
  27     ASSERT_VALID_PTR( fh );
  28     ASSERT
  29     (
  30            mode == OFFSET_BEGINNING
  31         || mode == OFFSET_END
  32         || mode == OFFSET_CURRENT
  33     );
  34
  35     /* Prepare I/O request. */
  36     InitIOFS( &iofs, FSA_SEEK, DOSBase );
  37
  38     iofs.IOFS.io_Device = fh->fh_Device;
  39     iofs.IOFS.io_Unit   = fh->fh_Unit;
  40
  41     iofs.io_Union.io_SEEK.io_Offset   = (QUAD)position;
  42     iofs.io_Union.io_SEEK.io_SeekMode = mode;
  43
  44     /* send the request, with error reporting */
  45     do {
  46         DosDoIO(&iofs.IOFS);
  47     } while (iofs.io_DosError != 0 && ErrorReport(iofs.io_DosError, REPORT_STREAM, fh, NULL) == DOSFALSE);
  48
  49     return iofs.io_DosError == 0 ? (LONG) iofs.io_Union.io_SEEK.io_Offset : -1;
  50 }