Annotation of sys/ufs/ffs/ffs_tables.c, Revision 1.1.1.1
1.1 nbrk 1: /* $OpenBSD: ffs_tables.c,v 1.5 2003/08/26 16:10:57 mickey Exp $ */
2: /* $NetBSD: ffs_tables.c,v 1.2 1994/06/29 06:46:35 cgd Exp $ */
3:
4: /*
5: * Copyright (c) 1982, 1986, 1993
6: * The Regents of the University of California. All rights reserved.
7: *
8: * Redistribution and use in source and binary forms, with or without
9: * modification, are permitted provided that the following conditions
10: * are met:
11: * 1. Redistributions of source code must retain the above copyright
12: * notice, this list of conditions and the following disclaimer.
13: * 2. Redistributions in binary form must reproduce the above copyright
14: * notice, this list of conditions and the following disclaimer in the
15: * documentation and/or other materials provided with the distribution.
16: * 3. Neither the name of the University nor the names of its contributors
17: * may be used to endorse or promote products derived from this software
18: * without specific prior written permission.
19: *
20: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30: * SUCH DAMAGE.
31: *
32: * @(#)ffs_tables.c 8.1 (Berkeley) 6/11/93
33: */
34:
35: #include <sys/param.h>
36: #include <ufs/ffs/fs.h>
37:
38: /*
39: * Bit patterns for identifying fragments in the block map
40: * used as ((map & around) == inside)
41: */
42: const int around[9] = {
43: 0x3, 0x7, 0xf, 0x1f, 0x3f, 0x7f, 0xff, 0x1ff, 0x3ff
44: };
45: const int inside[9] = {
46: 0x0, 0x2, 0x6, 0xe, 0x1e, 0x3e, 0x7e, 0xfe, 0x1fe
47: };
48:
49: /*
50: * Given a block map bit pattern, the frag tables tell whether a
51: * particular size fragment is available.
52: *
53: * used as:
54: * if ((1 << (size - 1)) & fragtbl[fs->fs_frag][map] {
55: * at least one fragment of the indicated size is available
56: * }
57: *
58: * These tables are used by the scanc instruction on the VAX to
59: * quickly find an appropriate fragment.
60: */
61: const u_char fragtbl124[256] = {
62: 0x00, 0x16, 0x16, 0x2a, 0x16, 0x16, 0x26, 0x4e,
63: 0x16, 0x16, 0x16, 0x3e, 0x2a, 0x3e, 0x4e, 0x8a,
64: 0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
65: 0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
66: 0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
67: 0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
68: 0x2a, 0x3e, 0x3e, 0x2a, 0x3e, 0x3e, 0x2e, 0x6e,
69: 0x3e, 0x3e, 0x3e, 0x3e, 0x2a, 0x3e, 0x6e, 0xaa,
70: 0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
71: 0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
72: 0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
73: 0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
74: 0x26, 0x36, 0x36, 0x2e, 0x36, 0x36, 0x26, 0x6e,
75: 0x36, 0x36, 0x36, 0x3e, 0x2e, 0x3e, 0x6e, 0xae,
76: 0x4e, 0x5e, 0x5e, 0x6e, 0x5e, 0x5e, 0x6e, 0x4e,
77: 0x5e, 0x5e, 0x5e, 0x7e, 0x6e, 0x7e, 0x4e, 0xce,
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: 0x16, 0x16, 0x16, 0x3e, 0x16, 0x16, 0x36, 0x5e,
83: 0x16, 0x16, 0x16, 0x3e, 0x3e, 0x3e, 0x5e, 0x9e,
84: 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x7e,
85: 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x7e, 0xbe,
86: 0x2a, 0x3e, 0x3e, 0x2a, 0x3e, 0x3e, 0x2e, 0x6e,
87: 0x3e, 0x3e, 0x3e, 0x3e, 0x2a, 0x3e, 0x6e, 0xaa,
88: 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x7e,
89: 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x3e, 0x7e, 0xbe,
90: 0x4e, 0x5e, 0x5e, 0x6e, 0x5e, 0x5e, 0x6e, 0x4e,
91: 0x5e, 0x5e, 0x5e, 0x7e, 0x6e, 0x7e, 0x4e, 0xce,
92: 0x8a, 0x9e, 0x9e, 0xaa, 0x9e, 0x9e, 0xae, 0xce,
93: 0x9e, 0x9e, 0x9e, 0xbe, 0xaa, 0xbe, 0xce, 0x8a,
94: };
95:
96: const u_char fragtbl8[256] = {
97: 0x00, 0x01, 0x01, 0x02, 0x01, 0x01, 0x02, 0x04,
98: 0x01, 0x01, 0x01, 0x03, 0x02, 0x03, 0x04, 0x08,
99: 0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
100: 0x02, 0x03, 0x03, 0x02, 0x04, 0x05, 0x08, 0x10,
101: 0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
102: 0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
103: 0x02, 0x03, 0x03, 0x02, 0x03, 0x03, 0x02, 0x06,
104: 0x04, 0x05, 0x05, 0x06, 0x08, 0x09, 0x10, 0x20,
105: 0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
106: 0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
107: 0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
108: 0x03, 0x03, 0x03, 0x03, 0x05, 0x05, 0x09, 0x11,
109: 0x02, 0x03, 0x03, 0x02, 0x03, 0x03, 0x02, 0x06,
110: 0x03, 0x03, 0x03, 0x03, 0x02, 0x03, 0x06, 0x0a,
111: 0x04, 0x05, 0x05, 0x06, 0x05, 0x05, 0x06, 0x04,
112: 0x08, 0x09, 0x09, 0x0a, 0x10, 0x11, 0x20, 0x40,
113: 0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
114: 0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
115: 0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
116: 0x03, 0x03, 0x03, 0x03, 0x05, 0x05, 0x09, 0x11,
117: 0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05,
118: 0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
119: 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x07,
120: 0x05, 0x05, 0x05, 0x07, 0x09, 0x09, 0x11, 0x21,
121: 0x02, 0x03, 0x03, 0x02, 0x03, 0x03, 0x02, 0x06,
122: 0x03, 0x03, 0x03, 0x03, 0x02, 0x03, 0x06, 0x0a,
123: 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x07,
124: 0x02, 0x03, 0x03, 0x02, 0x06, 0x07, 0x0a, 0x12,
125: 0x04, 0x05, 0x05, 0x06, 0x05, 0x05, 0x06, 0x04,
126: 0x05, 0x05, 0x05, 0x07, 0x06, 0x07, 0x04, 0x0c,
127: 0x08, 0x09, 0x09, 0x0a, 0x09, 0x09, 0x0a, 0x0c,
128: 0x10, 0x11, 0x11, 0x12, 0x20, 0x21, 0x40, 0x80,
129: };
130:
131: /*
132: * The actual fragtbl array.
133: */
134: const u_char *fragtbl[MAXFRAG + 1] = {
135: 0, fragtbl124, fragtbl124, 0, fragtbl124, 0, 0, 0, fragtbl8,
136: };
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