xref: /original-bsd/sys/ufs/ffs/ffs_subr.c (revision e25934f4)

/*
 * Copyright (c) 1982, 1986, 1989 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 *	@(#)ffs_subr.c	7.12 (Berkeley) 05/10/90
 */

#ifdef KERNEL
#include "param.h"
#include "../ufs/fs.h"
#else
#include <sys/param.h>
#include <ufs/fs.h>
#endif

extern	int around[9];
extern	int inside[9];
extern	u_char *fragtbl[];

/*
 * Update the frsum fields to reflect addition or deletion
 * of some frags.
 */
fragacct(fs, fragmap, fraglist, cnt)
	struct fs *fs;
	int fragmap;
	long fraglist[];
	int cnt;
{
	int inblk;
	register int field, subfield;
	register int siz, pos;

	inblk = (int)(fragtbl[fs->fs_frag][fragmap]) << 1;
	fragmap <<= 1;
	for (siz = 1; siz < fs->fs_frag; siz++) {
		if ((inblk & (1 << (siz + (fs->fs_frag % NBBY)))) == 0)
			continue;
		field = around[siz];
		subfield = inside[siz];
		for (pos = siz; pos <= fs->fs_frag; pos++) {
			if ((fragmap & field) == subfield) {
				fraglist[siz] += cnt;
				pos += siz;
				field <<= siz;
				subfield <<= siz;
			}
			field <<= 1;
			subfield <<= 1;
		}
	}
}

/*
 * block operations
 *
 * check if a block is available
 */
isblock(fs, cp, h)
	struct fs *fs;
	unsigned char *cp;
	daddr_t h;
{
	unsigned char mask;

	switch ((int)fs->fs_frag) {
	case 8:
		return (cp[h] == 0xff);
	case 4:
		mask = 0x0f << ((h & 0x1) << 2);
		return ((cp[h >> 1] & mask) == mask);
	case 2:
		mask = 0x03 << ((h & 0x3) << 1);
		return ((cp[h >> 2] & mask) == mask);
	case 1:
		mask = 0x01 << (h & 0x7);
		return ((cp[h >> 3] & mask) == mask);
	default:
		panic("isblock");
		return (NULL);
	}
}

/*
 * take a block out of the map
 */
clrblock(fs, cp, h)
	struct fs *fs;
	u_char *cp;
	daddr_t h;
{

	switch ((int)fs->fs_frag) {
	case 8:
		cp[h] = 0;
		return;
	case 4:
		cp[h >> 1] &= ~(0x0f << ((h & 0x1) << 2));
		return;
	case 2:
		cp[h >> 2] &= ~(0x03 << ((h & 0x3) << 1));
		return;
	case 1:
		cp[h >> 3] &= ~(0x01 << (h & 0x7));
		return;
	default:
		panic("clrblock");
	}
}

/*
 * put a block into the map
 */
setblock(fs, cp, h)
	struct fs *fs;
	unsigned char *cp;
	daddr_t h;
{

	switch ((int)fs->fs_frag) {

	case 8:
		cp[h] = 0xff;
		return;
	case 4:
		cp[h >> 1] |= (0x0f << ((h & 0x1) << 2));
		return;
	case 2:
		cp[h >> 2] |= (0x03 << ((h & 0x3) << 1));
		return;
	case 1:
		cp[h >> 3] |= (0x01 << (h & 0x7));
		return;
	default:
		panic("setblock");
	}
}

#if (!defined(vax) && !defined(tahoe) && !defined(hp300)) \
	|| defined(VAX630) || defined(VAX650)
/*
 * C definitions of special instructions.
 * Normally expanded with inline.
 */
scanc(size, cp, table, mask)
	u_int size;
	register u_char *cp, table[];
	register u_char mask;
{
	register u_char *end = &cp[size];

	while (cp < end && (table[*cp] & mask) == 0)
		cp++;
	return (end - cp);
}
#endif

#if !defined(vax) && !defined(tahoe) && !defined(hp300)
skpc(mask, size, cp)
	register u_char mask;
	u_int size;
	register u_char *cp;
{
	register u_char *end = &cp[size];

	while (cp < end && *cp == mask)
		cp++;
	return (end - cp);
}

locc(mask, size, cp)
	register u_char mask;
	u_int size;
	register u_char *cp;
{
	register u_char *end = &cp[size];

	while (cp < end && *cp != mask)
		cp++;
	return (end - cp);
}
#endif