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. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  *      @(#)ffs_tables.c        8.1 (Berkeley) 6/11/93
  34  * $FreeBSD: src/sys/ufs/ffs/ffs_tables.c,v 1.7 1999/08/28 00:52:22 peter Exp $
  35  * $DragonFly: src/sys/vfs/ufs/ffs_tables.c,v 1.2 2003/06/17 04:28:59 dillon Exp $
  36  */
  37
  38 #include <sys/param.h>
  39
  40 /*
  41  * Bit patterns for identifying fragments in the block map
  42  * used as ((map & around) == inside)
  43  */
  44 int around[9] = {
  45         0x3, 0x7, 0xf, 0x1f, 0x3f, 0x7f, 0xff, 0x1ff, 0x3ff
  46 };
  47 int inside[9] = {
  48         0x0, 0x2, 0x6, 0xe, 0x1e, 0x3e, 0x7e, 0xfe, 0x1fe
  49 };
  50
  51 /*
  52  * Given a block map bit pattern, the frag tables tell whether a
  53  * particular size fragment is available.
  54  *
  55  * used as:
  56  * if ((1 << (size - 1)) & fragtbl[fs->fs_frag][map] {
  57  *      at least one fragment of the indicated size is available
  58  * }
  59  *
  60  * These tables are used by the scanc instruction on the VAX to
  61  * quickly find an appropriate fragment.
  62  */
  63 static u_char fragtbl124[256] = {
  64         0x00, 0x16, 0x16, 0x2a, 0x16, 0x16, 0x26, 0x4e,
  65         0x16, 0x16, 0x16, 0x3e, 0x2a, 0x3e, 0x4e, 0x8a,
  66         0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
  67         0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
  68         0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
  69         0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
  70         0x2a, 0x3e, 0x3e, 0x2a, 0x3e, 0x3e, 0x2e, 0x6e,
  71         0x3e, 0x3e, 0x3e, 0x3e, 0x2a, 0x3e, 0x6e, 0xaa,
  72         0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
  73         0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
  74         0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
  75         0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
  76         0x26, 0x36, 0x36, 0x2e, 0x36, 0x36, 0x26, 0x6e,
  77         0x36, 0x36, 0x36, 0x3e, 0x2e, 0x3e, 0x6e, 0xae,
  78         0x4e, 0x5e, 0x5e, 0x6e, 0x5e, 0x5e, 0x6e, 0x4e,
  79         0x5e, 0x5e, 0x5e, 0x7e, 0x6e, 0x7e, 0x4e, 0xce,
  80         0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
  81         0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
  82         0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
  83         0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
  84         0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
  85         0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
  86         0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x7e,
  87         0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x7e, 0xbe,
  88         0x2a, 0x3e, 0x3e, 0x2a, 0x3e, 0x3e, 0x2e, 0x6e,
  89         0x3e, 0x3e, 0x3e, 0x3e, 0x2a, 0x3e, 0x6e, 0xaa,
  90         0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x7e,
  91         0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x7e, 0xbe,
  92         0x4e, 0x5e, 0x5e, 0x6e, 0x5e, 0x5e, 0x6e, 0x4e,
  93         0x5e, 0x5e, 0x5e, 0x7e, 0x6e, 0x7e, 0x4e, 0xce,
  94         0x8a, 0x9e, 0x9e, 0xaa, 0x9e, 0x9e, 0xae, 0xce,
  95         0x9e, 0x9e, 0x9e, 0xbe, 0xaa, 0xbe, 0xce, 0x8a,
  96 };
  97
  98 static u_char fragtbl8[256] = {
  99         0x00, 0x01, 0x01, 0x02, 0x01, 0x01, 0x02, 0x04,
 100         0x01, 0x01, 0x01, 0x03, 0x02, 0x03, 0x04, 0x08,
 101         0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
 102         0x02, 0x03, 0x03, 0x02, 0x04, 0x05, 0x08, 0x10,
 103         0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
 104         0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
 105         0x02, 0x03, 0x03, 0x02, 0x03, 0x03, 0x02, 0x06,
 106         0x04, 0x05, 0x05, 0x06, 0x08, 0x09, 0x10, 0x20,
 107         0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
 108         0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
 109         0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
 110         0x03, 0x03, 0x03, 0x03, 0x05, 0x05, 0x09, 0x11,
 111         0x02, 0x03, 0x03, 0x02, 0x03, 0x03, 0x02, 0x06,
 112         0x03, 0x03, 0x03, 0x03, 0x02, 0x03, 0x06, 0x0a,
 113         0x04, 0x05, 0x05, 0x06, 0x05, 0x05, 0x06, 0x04,
 114         0x08, 0x09, 0x09, 0x0a, 0x10, 0x11, 0x20, 0x40,
 115         0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
 116         0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
 117         0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
 118         0x03, 0x03, 0x03, 0x03, 0x05, 0x05, 0x09, 0x11,
 119         0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
 120         0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
 121         0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x07,
 122         0x05, 0x05, 0x05, 0x07, 0x09, 0x09, 0x11, 0x21,
 123         0x02, 0x03, 0x03, 0x02, 0x03, 0x03, 0x02, 0x06,
 124         0x03, 0x03, 0x03, 0x03, 0x02, 0x03, 0x06, 0x0a,
 125         0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x07,
 126         0x02, 0x03, 0x03, 0x02, 0x06, 0x07, 0x0a, 0x12,
 127         0x04, 0x05, 0x05, 0x06, 0x05, 0x05, 0x06, 0x04,
 128         0x05, 0x05, 0x05, 0x07, 0x06, 0x07, 0x04, 0x0c,
 129         0x08, 0x09, 0x09, 0x0a, 0x09, 0x09, 0x0a, 0x0c,
 130         0x10, 0x11, 0x11, 0x12, 0x20, 0x21, 0x40, 0x80,
 131 };
 132
 133 /*
 134  * The actual fragtbl array.
 135  */
 136 u_char *fragtbl[MAXFRAG + 1] = {
 137         0, fragtbl124, fragtbl124, 0, fragtbl124, 0, 0, 0, fragtbl8,
 138 };