/* $Copyright:	$
 * Copyright (c) 1984, 1985, 1986, 1987, 1988, 1989, 1990 
 * Sequent Computer Systems, Inc.   All rights reserved.
 *  
 * This software is furnished under a license and may be used
 * only in accordance with the terms of that license and with the
 * inclusion of the above copyright notice.   This software may not
 * be provided or otherwise made available to, or used by, any
 * other person.  No title to or ownership of the software is
 * hereby transferred.
 */

#ident		"$Header: ufsdir.h 1.11 89/08/07 $"

#ifndef	_SYS_UFSDIR_H_

/*
 * dir.h
 *	Directory entry structures.
 */

/* $Log:	ufsdir.h,v $
 */

/*
 * A directory consists of some number of blocks of DIRBLKSIZ
 * bytes, where DIRBLKSIZ is chosen such that it can be transferred
 * to disk in a single atomic operation (e.g. 512 bytes on most machines).
 *
 * Each DIRBLKSIZ byte block contains some number of directory entry
 * structures, which are of variable length.  Each directory entry has
 * a struct direct at the front of it, containing its inode number,
 * the length of the entry, and the length of the name contained in
 * the entry.  These are followed by the name padded to a 4 byte boundary
 * with null bytes.  All names are guaranteed null terminated.
 * The d_namlen value does NOT include the terminating null byte.
 * The maximum length of a name in a directory is UFS_MAXNAMLEN (param.h).
 *
 * The macro DIRLEN(dp) gives the amount of space required to represent
 * a directory entry.  Free space in a directory is represented by
 * entries which have dp->d_reclen > DIRLEN(dp).  All DIRBLKSIZ bytes
 * in a directory block are claimed by the directory entries.  This
 * usually results in the last entry in a directory having a large
 * dp->d_reclen.  When entries are deleted from a directory, the
 * space is returned to the previous entry in the same directory
 * block by increasing its dp->d_reclen.  If the first entry of
 * a directory block is free, then its dp->d_ino is set to 0.
 * Entries other than the first in a directory do not normally have
 * dp->d_ino set to 0.
 */

#define DIRBLKSIZ	DEV_BSIZE

#define UFS_MAXNAMLEN	255

struct	direct {
 	ulong	d_fileno;		/* file number of entry */
	ushort	d_reclen;		/* length of this record */
	ushort	d_namlen;		/* length of string in d_name */
	char	d_name[UFS_MAXNAMLEN + 1];	/* name must be no longer than this */
};
#define d_ino	d_fileno		/* compatablity */

/*
 * The DIRLEN macro gives the minimum record length which will hold
 * the directory entry.  This requires the amount of space in struct direct
 * without the d_name field, plus enough space for the name with a terminating
 * null byte (dp->d_namlen+1), rounded up to a 4 byte boundary.
 */
#undef DIRLEN
#define DIRLEN(dp) \
    ((sizeof (struct direct) - (UFS_MAXNAMLEN+1)) + (((dp)->d_namlen+1 + 3) &~ 3))

#ifdef	INKERNEL
/*
 * Template for manipulating directories.
 * Should use struct direct's, but the name field
 * is UFS_MAXNAMLEN - 1, and this just won't do.
 */
struct dirtemplate {
	ulong	dot_ino;
	short	dot_reclen;
	short	dot_namlen;
	char	dot_name[4];		/* must be multiple of 4 */
	ulong	dotdot_ino;
	short	dotdot_reclen;
	short	dotdot_namlen;
	char	dotdot_name[4];		/* ditto */
};


/*
 * macro to calculate number of bytes to hold a "translated" dirent
 * structure (system V), based on the namelength (without terminating
 * null) of the name to be placed in the entry.
 *
 */

#ifndef NBPW
#define NBPW	sizeof(int)
#endif /* NBPW */

#define DNTSIZ(namelen) \
(((int)(((struct dirent *)0)->d_name)+ (namelen) +1 + (NBPW-1)) & ~(NBPW-1))

#endif	/* INKERNEL */

#define	_SYS_UFSDIR_H_
#endif	/* _SYS_UFSDIR_H_ */
