1 /*
2 * GRUB -- GRand Unified Bootloader
3 * Copyright (C) 1999,2000,2001,2002,2003,2004 Free Software Foundation, Inc.
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; If not, see <http://www.gnu.org/licenses/>.
17 */
18 /*
19 * Copyright 2007 Sun Microsystems, Inc. All rights reserved.
20 * Use is subject to license terms.
21 */
22
23 #pragma ident "%Z%%M% %I% %E% SMI"
24
25 #include "fsys_zfs.h"
26
27 #define MATCH_BITS 6
28 #define MATCH_MIN 3
29 #define OFFSET_MASK ((1 << (16 - MATCH_BITS)) - 1)
30
31
32 /*ARGSUSED*/
33 int
lzjb_decompress(void * s_start,void * d_start,size_t s_len,size_t d_len)34 lzjb_decompress(void *s_start, void *d_start, size_t s_len, size_t d_len)
35 {
36 uint8_t *src = s_start;
37 uint8_t *dst = d_start;
38 uint8_t *d_end = (uint8_t *)d_start + d_len;
39 uint8_t *cpy, copymap = '\0';
40 int copymask = 1 << (NBBY - 1);
41
42 while (dst < d_end) {
43 if ((copymask <<= 1) == (1 << NBBY)) {
44 copymask = 1;
45 copymap = *src++;
46 }
47 if (copymap & copymask) {
48 int mlen = (src[0] >> (NBBY - MATCH_BITS)) + MATCH_MIN;
49 int offset = ((src[0] << NBBY) | src[1]) & OFFSET_MASK;
50 src += 2;
51 if ((cpy = dst - offset) < (uint8_t *)d_start)
52 return (-1);
53 while (--mlen >= 0 && dst < d_end)
54 *dst++ = *cpy++;
55 } else {
56 *dst++ = *src++;
57 }
58 }
59 return (0);
60 }
61