ufs_tables.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

#ifndef lint
static char *sccsid = "@(#)ufs_tables.c	4.1	(ULTRIX)	7/2/90";
#endif

/************************************************************************
 *									*
 *			Copyright (c) 1986 by				*
 *		Digital Equipment Corporation, Maynard, MA		*
 *			All rights reserved.				*
 *									*
 *   This software is furnished under a license and may be used and	*
 *   copied  only  in accordance with the terms of such license and	*
 *   with the  inclusion  of  the  above  copyright  notice.   This	*
 *   software  or  any  other copies thereof may not be provided or	*
 *   otherwise made available to any other person.  No title to and	*
 *   ownership of the software is hereby transferred.			*
 *									*
 *   This software is  derived  from  software  received  from  the	*
 *   University    of   California,   Berkeley,   and   from   Bell	*
 *   Laboratories.  Use, duplication, or disclosure is  subject  to	*
 *   restrictions  under  license  agreements  with  University  of	*
 *   California and with AT&T.						*
 *									*
 *   The information in this software is subject to change  without	*
 *   notice  and should not be construed as a commitment by Digital	*
 *   Equipment Corporation.						*
 *									*
 *   Digital assumes no responsibility for the use  or  reliability	*
 *   of its software on equipment which is not supplied by Digital.	*
 *									*
 ************************************************************************/
#ifdef KERNEL
#include "../h/param.h"
#else
#include <sys/param.h>
#endif KERNEL

/*
 * Bit patterns for identifying fragments in the block map
 * used as ((map & around) == inside)
 */
int around[9] = {
	0x3, 0x7, 0xf, 0x1f, 0x3f, 0x7f, 0xff, 0x1ff, 0x3ff
};
int inside[9] = {
	0x0, 0x2, 0x6, 0xe, 0x1e, 0x3e, 0x7e, 0xfe, 0x1fe
};

/*
 * Given a block map bit pattern, the frag tables tell whether a
 * particular size fragment is available. 
 *
 * used as:
 * if ((1 << (size - 1)) & fragtbl[fs->fs_frag][map] {
 *	at least one fragment of the indicated size is available
 * }
 *
 * These tables are used by the scanc instruction on the VAX to
 * quickly find an appropriate fragment.
 */
u_char fragtbl124[256] = {
	0x00, 0x16, 0x16, 0x2a, 0x16, 0x16, 0x26, 0x4e,
	0x16, 0x16, 0x16, 0x3e, 0x2a, 0x3e, 0x4e, 0x8a,
	0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
	0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
	0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
	0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
	0x2a, 0x3e, 0x3e, 0x2a, 0x3e, 0x3e, 0x2e, 0x6e,
	0x3e, 0x3e, 0x3e, 0x3e, 0x2a, 0x3e, 0x6e, 0xaa,
	0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
	0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
	0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
	0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
	0x26, 0x36, 0x36, 0x2e, 0x36, 0x36, 0x26, 0x6e,
	0x36, 0x36, 0x36, 0x3e, 0x2e, 0x3e, 0x6e, 0xae,
	0x4e, 0x5e, 0x5e, 0x6e, 0x5e, 0x5e, 0x6e, 0x4e,
	0x5e, 0x5e, 0x5e, 0x7e, 0x6e, 0x7e, 0x4e, 0xce,
	0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
	0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
	0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
	0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
	0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
	0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
	0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x7e,
	0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x7e, 0xbe,
	0x2a, 0x3e, 0x3e, 0x2a, 0x3e, 0x3e, 0x2e, 0x6e,
	0x3e, 0x3e, 0x3e, 0x3e, 0x2a, 0x3e, 0x6e, 0xaa,
	0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x7e,
	0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x7e, 0xbe,
	0x4e, 0x5e, 0x5e, 0x6e, 0x5e, 0x5e, 0x6e, 0x4e,
	0x5e, 0x5e, 0x5e, 0x7e, 0x6e, 0x7e, 0x4e, 0xce,
	0x8a, 0x9e, 0x9e, 0xaa, 0x9e, 0x9e, 0xae, 0xce,
	0x9e, 0x9e, 0x9e, 0xbe, 0xaa, 0xbe, 0xce, 0x8a,
};

u_char fragtbl8[256] = {
	0x00, 0x01, 0x01, 0x02, 0x01, 0x01, 0x02, 0x04,
	0x01, 0x01, 0x01, 0x03, 0x02, 0x03, 0x04, 0x08,
	0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
	0x02, 0x03, 0x03, 0x02, 0x04, 0x05, 0x08, 0x10,
	0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
	0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
	0x02, 0x03, 0x03, 0x02, 0x03, 0x03, 0x02, 0x06,
	0x04, 0x05, 0x05, 0x06, 0x08, 0x09, 0x10, 0x20,
	0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
	0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
	0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
	0x03, 0x03, 0x03, 0x03, 0x05, 0x05, 0x09, 0x11,
	0x02, 0x03, 0x03, 0x02, 0x03, 0x03, 0x02, 0x06,
	0x03, 0x03, 0x03, 0x03, 0x02, 0x03, 0x06, 0x0a,
	0x04, 0x05, 0x05, 0x06, 0x05, 0x05, 0x06, 0x04,
	0x08, 0x09, 0x09, 0x0a, 0x10, 0x11, 0x20, 0x40,
	0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
	0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
	0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
	0x03, 0x03, 0x03, 0x03, 0x05, 0x05, 0x09, 0x11,
	0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
	0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
	0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x07,
	0x05, 0x05, 0x05, 0x07, 0x09, 0x09, 0x11, 0x21,
	0x02, 0x03, 0x03, 0x02, 0x03, 0x03, 0x02, 0x06,
	0x03, 0x03, 0x03, 0x03, 0x02, 0x03, 0x06, 0x0a,
	0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x07,
	0x02, 0x03, 0x03, 0x02, 0x06, 0x07, 0x0a, 0x12,
	0x04, 0x05, 0x05, 0x06, 0x05, 0x05, 0x06, 0x04,
	0x05, 0x05, 0x05, 0x07, 0x06, 0x07, 0x04, 0x0c,
	0x08, 0x09, 0x09, 0x0a, 0x09, 0x09, 0x0a, 0x0c,
	0x10, 0x11, 0x11, 0x12, 0x20, 0x21, 0x40, 0x80,
};

/*
 * The actual fragtbl array.
 */
u_char *fragtbl[MAXFRAG + 1] = {
	0, fragtbl124, fragtbl124, 0, fragtbl124, 0, 0, 0, fragtbl8,
};