sys/ufs/ffs/ffs_tables.c

   1 /*      $NetBSD: ffs_tables.c,v 1.9 2005/12/11 12:25:25 christos Exp $  */
   2
   3 /*
   4  * Copyright (c) 1982, 1986, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  *
  31  *      @(#)ffs_tables.c        8.1 (Berkeley) 6/11/93
  32  */
  33
  34 #if HAVE_NBTOOL_CONFIG_H
  35 #include "nbtool_config.h"
  36 #endif
  37
  38 #include <sys/cdefs.h>
  39 __KERNEL_RCSID(0, "$NetBSD: ffs_tables.c,v 1.9 2005/12/11 12:25:25 christos Exp $");
  40
  41 #include <sys/param.h>
  42
  43 /*
  44  * Bit patterns for identifying fragments in the block map
  45  * used as ((map & around) == inside)
  46  */
  47 const int around[9] = {
  48         0x3, 0x7, 0xf, 0x1f, 0x3f, 0x7f, 0xff, 0x1ff, 0x3ff
  49 };
  50 const int inside[9] = {
  51         0x0, 0x2, 0x6, 0xe, 0x1e, 0x3e, 0x7e, 0xfe, 0x1fe
  52 };
  53
  54 /*
  55  * Given a block map bit pattern, the frag tables tell whether a
  56  * particular size fragment is available.
  57  *
  58  * used as:
  59  * if ((1 << (size - 1)) & fragtbl[fs->fs_frag][map] {
  60  *      at least one fragment of the indicated size is available
  61  * }
  62  *
  63  * These tables are used by the scanc instruction on the VAX to
  64  * quickly find an appropriate fragment.
  65  */
  66 const u_char fragtbl124[256] = {
  67         0x00, 0x16, 0x16, 0x2a, 0x16, 0x16, 0x26, 0x4e,
  68         0x16, 0x16, 0x16, 0x3e, 0x2a, 0x3e, 0x4e, 0x8a,
  69         0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
  70         0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
  71         0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
  72         0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
  73         0x2a, 0x3e, 0x3e, 0x2a, 0x3e, 0x3e, 0x2e, 0x6e,
  74         0x3e, 0x3e, 0x3e, 0x3e, 0x2a, 0x3e, 0x6e, 0xaa,
  75         0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
  76         0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
  77         0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
  78         0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
  79         0x26, 0x36, 0x36, 0x2e, 0x36, 0x36, 0x26, 0x6e,
  80         0x36, 0x36, 0x36, 0x3e, 0x2e, 0x3e, 0x6e, 0xae,
  81         0x4e, 0x5e, 0x5e, 0x6e, 0x5e, 0x5e, 0x6e, 0x4e,
  82         0x5e, 0x5e, 0x5e, 0x7e, 0x6e, 0x7e, 0x4e, 0xce,
  83         0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
  84         0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
  85         0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
  86         0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
  87         0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
  88         0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
  89         0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x7e,
  90         0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x7e, 0xbe,
  91         0x2a, 0x3e, 0x3e, 0x2a, 0x3e, 0x3e, 0x2e, 0x6e,
  92         0x3e, 0x3e, 0x3e, 0x3e, 0x2a, 0x3e, 0x6e, 0xaa,
  93         0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x7e,
  94         0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x7e, 0xbe,
  95         0x4e, 0x5e, 0x5e, 0x6e, 0x5e, 0x5e, 0x6e, 0x4e,
  96         0x5e, 0x5e, 0x5e, 0x7e, 0x6e, 0x7e, 0x4e, 0xce,
  97         0x8a, 0x9e, 0x9e, 0xaa, 0x9e, 0x9e, 0xae, 0xce,
  98         0x9e, 0x9e, 0x9e, 0xbe, 0xaa, 0xbe, 0xce, 0x8a,
  99 };
 100
 101 const u_char fragtbl8[256] = {
 102         0x00, 0x01, 0x01, 0x02, 0x01, 0x01, 0x02, 0x04,
 103         0x01, 0x01, 0x01, 0x03, 0x02, 0x03, 0x04, 0x08,
 104         0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
 105         0x02, 0x03, 0x03, 0x02, 0x04, 0x05, 0x08, 0x10,
 106         0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
 107         0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
 108         0x02, 0x03, 0x03, 0x02, 0x03, 0x03, 0x02, 0x06,
 109         0x04, 0x05, 0x05, 0x06, 0x08, 0x09, 0x10, 0x20,
 110         0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
 111         0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
 112         0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
 113         0x03, 0x03, 0x03, 0x03, 0x05, 0x05, 0x09, 0x11,
 114         0x02, 0x03, 0x03, 0x02, 0x03, 0x03, 0x02, 0x06,
 115         0x03, 0x03, 0x03, 0x03, 0x02, 0x03, 0x06, 0x0a,
 116         0x04, 0x05, 0x05, 0x06, 0x05, 0x05, 0x06, 0x04,
 117         0x08, 0x09, 0x09, 0x0a, 0x10, 0x11, 0x20, 0x40,
 118         0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
 119         0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
 120         0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
 121         0x03, 0x03, 0x03, 0x03, 0x05, 0x05, 0x09, 0x11,
 122         0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
 123         0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
 124         0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x07,
 125         0x05, 0x05, 0x05, 0x07, 0x09, 0x09, 0x11, 0x21,
 126         0x02, 0x03, 0x03, 0x02, 0x03, 0x03, 0x02, 0x06,
 127         0x03, 0x03, 0x03, 0x03, 0x02, 0x03, 0x06, 0x0a,
 128         0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x07,
 129         0x02, 0x03, 0x03, 0x02, 0x06, 0x07, 0x0a, 0x12,
 130         0x04, 0x05, 0x05, 0x06, 0x05, 0x05, 0x06, 0x04,
 131         0x05, 0x05, 0x05, 0x07, 0x06, 0x07, 0x04, 0x0c,
 132         0x08, 0x09, 0x09, 0x0a, 0x09, 0x09, 0x0a, 0x0c,
 133         0x10, 0x11, 0x11, 0x12, 0x20, 0x21, 0x40, 0x80,
 134 };
 135
 136 /*
 137  * The actual fragtbl array.
 138  */
 139 const u_char * const fragtbl[MAXFRAG + 1] = {
 140         0, fragtbl124, fragtbl124, 0, fragtbl124, 0, 0, 0, fragtbl8,
 141 };