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ffs_tables.c

/*-
 * Copyright (c) 1982, 1986, 1993
 *    The Regents of the University of California.  All rights reserved.
 *
 * 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.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 THE REGENTS OR CONTRIBUTORS 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.
 *
 *    @(#)ffs_tables.c  8.1 (Berkeley) 6/11/93
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/sys/ufs/ffs/ffs_tables.c,v 1.12 2005/01/07 02:29:26 imp Exp $");

#include <sys/param.h>
#include <ufs/ufs/dinode.h>
#include <ufs/ffs/fs.h>

/*
 * 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.
 */
static 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,
};

static 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,
};

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