rom/dos/addbuffers.c

   1 /*
   2     Copyright © 1995-2012, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Add or remove cache memory from a filesystem.
   6     Lang: English
   7 */
   8 #include <proto/exec.h>
   9 #include <dos/dosextens.h>
  10 #include "dos_intern.h"
  11
  12 /*****************************************************************************
  13
  14     NAME */
  15 #include <proto/dos.h>
  16
  17         AROS_LH2(LONG, AddBuffers,
  18
  19 /*  SYNOPSIS */
  20         AROS_LHA(CONST_STRPTR, devicename, D1),
  21         AROS_LHA(LONG,         numbuffers, D2),
  22
  23 /*  LOCATION */
  24         struct DosLibrary *, DOSBase, 122, Dos)
  25
  26 /*  FUNCTION
  27         Add or remove cache memory to/from a filesystem. The amount of memory
  28         per cache buffer and the limit depends on the filesystem.
  29
  30     INPUTS
  31         devicename - DOS device name (with trailing ':' and NUL terminated).
  32         numbuffers - Number of buffers to add. May be negative for decreasing.
  33
  34     RESULT
  35         DOSTRUE on success (IoErr() gives the actual number of buffers).
  36         DOSFALSE on error (IoErr() gives the error code).
  37         Some old filesystems return the actual buffer size. See the example
  38         for a workaround for that case.
  39
  40     NOTES
  41
  42     EXAMPLE
  43         LONG res1, res2;
  44         res1 = AddBuffers("df0:", 10);
  45         res2 = IoErr();
  46         if (res1 != DOSFALSE && res1 != DOSTRUE)
  47         {
  48             res2 = res1;
  49             res1 = DOSTRUE;
  50         }
  51
  52     BUGS
  53
  54     SEE ALSO
  55         IoErr()
  56
  57     INTERNALS
  58
  59     The error value in case of a filesystem error will be reported in
  60     the io_MORE_CACHE.io_NumBuffers field.
  61
  62 *****************************************************************************/
  63
  64 {
  65     AROS_LIBFUNC_INIT
  66
  67     struct DevProc *dvp;
  68     LONG ret;
  69
  70     /* get the device */
  71     if ((dvp = GetDeviceProc(devicename, NULL)) == NULL)
  72         return DOSFALSE;
  73
  74     /* we're only interested in real devices */
  75     if (dvp->dvp_DevNode == NULL ||
  76         dvp->dvp_DevNode->dol_Type != DLT_DEVICE) {
  77         FreeDeviceProc(dvp);
  78         SetIoErr(ERROR_DEVICE_NOT_MOUNTED);
  79         return DOSFALSE;
  80     }
  81
  82     ret = dopacket1(DOSBase, NULL, dvp->dvp_Port, ACTION_MORE_CACHE, numbuffers);
  83
  84     FreeDeviceProc(dvp);
  85
  86     return ret;
  87
  88     AROS_LIBFUNC_EXIT
  89 } /* AddBuffers */