sys/vfs/ufs/ffs_tables.c

   1 /*
   2  * Copyright (c) 1982, 1986, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  *      @(#)ffs_tables.c        8.1 (Berkeley) 6/11/93
  30  * $FreeBSD: src/sys/ufs/ffs/ffs_tables.c,v 1.7 1999/08/28 00:52:22 peter Exp $
  31  * $DragonFly: src/sys/vfs/ufs/ffs_tables.c,v 1.2 2003/06/17 04:28:59 dillon Exp $
  32  */
  33
  34 #include <sys/param.h>
  35
  36 /*
  37  * Bit patterns for identifying fragments in the block map
  38  * used as ((map & around) == inside)
  39  */
  40 int around[9] = {
  41         0x3, 0x7, 0xf, 0x1f, 0x3f, 0x7f, 0xff, 0x1ff, 0x3ff
  42 };
  43 int inside[9] = {
  44         0x0, 0x2, 0x6, 0xe, 0x1e, 0x3e, 0x7e, 0xfe, 0x1fe
  45 };
  46
  47 /*
  48  * Given a block map bit pattern, the frag tables tell whether a
  49  * particular size fragment is available.
  50  *
  51  * used as:
  52  * if ((1 << (size - 1)) & fragtbl[fs->fs_frag][map] {
  53  *      at least one fragment of the indicated size is available
  54  * }
  55  *
  56  * These tables are used by the scanc instruction on the VAX to
  57  * quickly find an appropriate fragment.
  58  */
  59 static u_char fragtbl124[256] = {
  60         0x00, 0x16, 0x16, 0x2a, 0x16, 0x16, 0x26, 0x4e,
  61         0x16, 0x16, 0x16, 0x3e, 0x2a, 0x3e, 0x4e, 0x8a,
  62         0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
  63         0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
  64         0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
  65         0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
  66         0x2a, 0x3e, 0x3e, 0x2a, 0x3e, 0x3e, 0x2e, 0x6e,
  67         0x3e, 0x3e, 0x3e, 0x3e, 0x2a, 0x3e, 0x6e, 0xaa,
  68         0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
  69         0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
  70         0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
  71         0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
  72         0x26, 0x36, 0x36, 0x2e, 0x36, 0x36, 0x26, 0x6e,
  73         0x36, 0x36, 0x36, 0x3e, 0x2e, 0x3e, 0x6e, 0xae,
  74         0x4e, 0x5e, 0x5e, 0x6e, 0x5e, 0x5e, 0x6e, 0x4e,
  75         0x5e, 0x5e, 0x5e, 0x7e, 0x6e, 0x7e, 0x4e, 0xce,
  76         0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
  77         0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
  78         0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
  79         0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
  80         0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
  81         0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
  82         0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x7e,
  83         0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x7e, 0xbe,
  84         0x2a, 0x3e, 0x3e, 0x2a, 0x3e, 0x3e, 0x2e, 0x6e,
  85         0x3e, 0x3e, 0x3e, 0x3e, 0x2a, 0x3e, 0x6e, 0xaa,
  86         0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x7e,
  87         0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x7e, 0xbe,
  88         0x4e, 0x5e, 0x5e, 0x6e, 0x5e, 0x5e, 0x6e, 0x4e,
  89         0x5e, 0x5e, 0x5e, 0x7e, 0x6e, 0x7e, 0x4e, 0xce,
  90         0x8a, 0x9e, 0x9e, 0xaa, 0x9e, 0x9e, 0xae, 0xce,
  91         0x9e, 0x9e, 0x9e, 0xbe, 0xaa, 0xbe, 0xce, 0x8a,
  92 };
  93
  94 static u_char fragtbl8[256] = {
  95         0x00, 0x01, 0x01, 0x02, 0x01, 0x01, 0x02, 0x04,
  96         0x01, 0x01, 0x01, 0x03, 0x02, 0x03, 0x04, 0x08,
  97         0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
  98         0x02, 0x03, 0x03, 0x02, 0x04, 0x05, 0x08, 0x10,
  99         0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
 100         0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
 101         0x02, 0x03, 0x03, 0x02, 0x03, 0x03, 0x02, 0x06,
 102         0x04, 0x05, 0x05, 0x06, 0x08, 0x09, 0x10, 0x20,
 103         0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
 104         0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
 105         0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
 106         0x03, 0x03, 0x03, 0x03, 0x05, 0x05, 0x09, 0x11,
 107         0x02, 0x03, 0x03, 0x02, 0x03, 0x03, 0x02, 0x06,
 108         0x03, 0x03, 0x03, 0x03, 0x02, 0x03, 0x06, 0x0a,
 109         0x04, 0x05, 0x05, 0x06, 0x05, 0x05, 0x06, 0x04,
 110         0x08, 0x09, 0x09, 0x0a, 0x10, 0x11, 0x20, 0x40,
 111         0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
 112         0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
 113         0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
 114         0x03, 0x03, 0x03, 0x03, 0x05, 0x05, 0x09, 0x11,
 115         0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
 116         0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
 117         0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x07,
 118         0x05, 0x05, 0x05, 0x07, 0x09, 0x09, 0x11, 0x21,
 119         0x02, 0x03, 0x03, 0x02, 0x03, 0x03, 0x02, 0x06,
 120         0x03, 0x03, 0x03, 0x03, 0x02, 0x03, 0x06, 0x0a,
 121         0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x07,
 122         0x02, 0x03, 0x03, 0x02, 0x06, 0x07, 0x0a, 0x12,
 123         0x04, 0x05, 0x05, 0x06, 0x05, 0x05, 0x06, 0x04,
 124         0x05, 0x05, 0x05, 0x07, 0x06, 0x07, 0x04, 0x0c,
 125         0x08, 0x09, 0x09, 0x0a, 0x09, 0x09, 0x0a, 0x0c,
 126         0x10, 0x11, 0x11, 0x12, 0x20, 0x21, 0x40, 0x80,
 127 };
 128
 129 /*
 130  * The actual fragtbl array.
 131  */
 132 u_char *fragtbl[MAXFRAG + 1] = {
 133         0, fragtbl124, fragtbl124, 0, fragtbl124, 0, 0, 0, fragtbl8,
 134 };