xref: /openbmc/u-boot/fs/zfs/zfs_lzjb.c (revision 00a2749d)
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, write to the Free Software
17  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18  */
19 /*
20  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
21  * Use is subject to license terms.
22  */
23 
24 #include <common.h>
25 #include <malloc.h>
26 #include <linux/stat.h>
27 #include <linux/time.h>
28 #include <linux/ctype.h>
29 #include <asm/byteorder.h>
30 #include "zfs_common.h"
31 
32 #include <zfs/zfs.h>
33 #include <zfs/zio.h>
34 #include <zfs/dnode.h>
35 #include <zfs/uberblock_impl.h>
36 #include <zfs/vdev_impl.h>
37 #include <zfs/zio_checksum.h>
38 #include <zfs/zap_impl.h>
39 #include <zfs/zap_leaf.h>
40 #include <zfs/zfs_znode.h>
41 #include <zfs/dmu.h>
42 #include <zfs/dmu_objset.h>
43 #include <zfs/dsl_dir.h>
44 #include <zfs/dsl_dataset.h>
45 
46 #define	MATCH_BITS	6
47 #define	MATCH_MIN	3
48 #define	OFFSET_MASK	((1 << (16 - MATCH_BITS)) - 1)
49 
50 /*
51  * Decompression Entry - lzjb
52  */
53 #ifndef	NBBY
54 #define	NBBY	8
55 #endif
56 
57 int
58 lzjb_decompress(void *s_start, void *d_start, uint32_t s_len,
59 				uint32_t d_len)
60 {
61 	uint8_t *src = s_start;
62 	uint8_t *dst = d_start;
63 	uint8_t *d_end = (uint8_t *) d_start + d_len;
64 	uint8_t *s_end = (uint8_t *) s_start + s_len;
65 	uint8_t *cpy, copymap = 0;
66 	int copymask = 1 << (NBBY - 1);
67 
68 	while (dst < d_end && src < s_end) {
69 		if ((copymask <<= 1) == (1 << NBBY)) {
70 			copymask = 1;
71 			copymap = *src++;
72 		}
73 		if (src >= s_end) {
74 			printf("lzjb decompression failed\n");
75 			return ZFS_ERR_BAD_FS;
76 		}
77 		if (copymap & copymask) {
78 			int mlen = (src[0] >> (NBBY - MATCH_BITS)) + MATCH_MIN;
79 			int offset = ((src[0] << NBBY) | src[1]) & OFFSET_MASK;
80 			src += 2;
81 			cpy = dst - offset;
82 			if (src > s_end || cpy < (uint8_t *) d_start) {
83 				printf("lzjb decompression failed\n");
84 				return ZFS_ERR_BAD_FS;
85 			}
86 			while (--mlen >= 0 && dst < d_end)
87 				*dst++ = *cpy++;
88 		} else {
89 			*dst++ = *src++;
90 		}
91 	}
92 	if (dst < d_end) {
93 		printf("lzjb decompression failed\n");
94 		return ZFS_ERR_BAD_FS;
95 	}
96 	return ZFS_ERR_NONE;
97 }
98