text: /*	$NetBSD: fat.h,v 1.16 2000/05/13 06:04:41 cgd Exp $	*/
  
  /*-
   * Copyright (C) 1994, 1997 Wolfgang Solfrank.
   * Copyright (C) 1994, 1997 TooLs GmbH.
   * All rights reserved.
   * Original code by Paul Popelka (paulp@uts.amdahl.com) (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 (paulp@uts.amdahl.com)
   *
   * 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
   */
  
  /*
   * 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 4078 ((CLUST_RSRVS - 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 it's unlimited wisdom desided 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)))
  
  #ifdef _KERNEL
  /*
   * 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 pcbmap __P((struct denode *, u_long, daddr_t *, u_long *, int *));
  int clusterfree __P((struct msdosfsmount *, u_long, u_long *));
  int clusteralloc __P((struct msdosfsmount *, u_long, u_long,u_long *,u_long *));
  int extendfile __P((struct denode *, u_long, struct buf **, u_long *, int));
  int fatentry __P((int, struct msdosfsmount *, u_long, u_long *, u_long));
  void fc_purge __P((struct denode *, u_int));
  void fc_lookup __P((struct denode *, u_long, u_long *, u_long *));
  int fillinusemap __P((struct msdosfsmount *));
  int freeclusterchain __P((struct msdosfsmount *, u_long));
  #endif	/* _KERNEL */
  