/*      $NetBSD: fat.h,v 1.10 2021/10/23 16:58:17 thorpej Exp $ */

/*-
* Copyright (C) 1994, 1997 Wolfgang Solfrank.
* Copyright (C) 1994, 1997 TooLs GmbH.
* All rights reserved.
* Original code by Paul Popelka ([email protected]) (see below).
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
*    must display the following acknowledgement:
*      This product includes software developed by TooLs GmbH.
* 4. The name of TooLs GmbH may not be used to endorse or promote products
*    derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Written by Paul Popelka ([email protected])
*
* You can do anything you want with this software, just don't say you wrote
* it, and don't remove this notice.
*
* This software is provided "as is".
*
* The author supplies this software to be publicly redistributed on the
* understanding that the author is not responsible for the correct
* functioning of this software in any circumstances and is not liable for
* any damages caused by this software.
*
* October 1992
*/

#ifndef _MSDOSFS_FAT_H_
#define _MSDOSFS_FAT_H_
/*
* Some useful cluster numbers.
*/
#define MSDOSFSROOT     0               /* cluster 0 means the root dir */
#define CLUST_FREE      0               /* cluster 0 also means a free cluster */
#define MSDOSFSFREE     CLUST_FREE
#define CLUST_FIRST     2               /* first legal cluster number */
#define CLUST_RSRVD     0xfffffff6      /* reserved cluster range */
#define CLUST_BAD       0xfffffff7      /* a cluster with a defect */
#define CLUST_EOFS      0xfffffff8      /* start of eof cluster range */
#define CLUST_EOFE      0xffffffff      /* end of eof cluster range */
#define CLUST_END       CLUST_EOFE      /* bigger than any valid cluster */

#define FAT12_MASK      0x00000fff      /* mask for 12 bit cluster numbers */
#define FAT16_MASK      0x0000ffff      /* mask for 16 bit cluster numbers */
#define FAT32_MASK      0x0fffffff      /* mask for FAT32 cluster numbers */

/*
* MSDOSFS:
* Return true if filesystem uses 12 bit FATs. Microsoft Programmer's
* Reference says if the maximum cluster number in a filesystem is greater
* than 4084 ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK) then we've got a
* 16 bit FAT filesystem. While mounting, the result of this test is stored
* in pm_fatentrysize.
* GEMDOS-flavour (atari):
* If the filesystem is on floppy we've got a 12 bit FAT filesystem, otherwise
* 16 bit. We check the d_type field in the disklabel struct while mounting
* and store the result in the pm_fatentrysize. Note that this kind of
* detection gets flakey when mounting a vnd-device.
*/
#define FAT12(pmp)      (pmp->pm_fatmask == FAT12_MASK)
#define FAT16(pmp)      (pmp->pm_fatmask == FAT16_MASK)
#define FAT32(pmp)      (pmp->pm_fatmask == FAT32_MASK)

/*
* M$ in its unlimited wisdom decided that EOF mark is anything
* between 0xfffffff8 and 0xffffffff (masked by appropriate fatmask,
* of course).
* Note that cn is supposed to be already adjusted accordingly to FAT type.
*/
#define MSDOSFSEOF(cn, fatmask) \
       (((cn) & CLUST_EOFS) == (CLUST_EOFS & (fatmask)))

#if defined(_KERNEL) || defined(MAKEFS)
/*
* These are the values for the function argument to the function
* fatentry().
*/
#define FAT_GET         0x0001  /* get a FAT entry */
#define FAT_SET         0x0002  /* set a FAT entry */
#define FAT_GET_AND_SET (FAT_GET | FAT_SET)

/*
* Flags to extendfile:
*/
#define DE_CLEAR        1       /* Zero out the blocks allocated */

int     msdosfs_pcbmap(struct denode *, u_long, daddr_t *, u_long *, int *);
int     msdosfs_clusterfree(struct msdosfsmount *, u_long, u_long *);
int     msdosfs_clusteralloc(struct msdosfsmount *, u_long, u_long, u_long *,
           u_long *);
int     msdosfs_extendfile(struct denode *, u_long, struct buf **, u_long *,
           int);
int     msdosfs_fatentry(int, struct msdosfsmount *, u_long, u_long *, u_long);
void    msdosfs_fc_purge(struct denode *, u_int);
void    msdosfs_fc_lookup(struct denode *, u_long, u_long *, u_long *);
int     msdosfs_fillinusemap(struct msdosfsmount *);
int     msdosfs_freeclusterchain(struct msdosfsmount *, u_long);
#endif /* _KERNEL || MAKEFS */
#endif /* _MSDOSFS_FAT_H_ */

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