1 /* $NetBSD: ntfs_compr.c,v 1.3 1999/07/26 14:02:31 jdolecek Exp $ */
2
3 /*-
4 * Copyright (c) 1998, 1999 Semen Ustimenko
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * $FreeBSD: releng/9.0/sys/fs/ntfs/ntfs_compr.c 86927 2001-11-26 23:45:12Z jhb $
29 */
30
31 #include <sys/param.h>
32 #include <sys/systm.h>
33 #include <sys/namei.h>
34 #include <sys/vnode.h>
35 #include <sys/mount.h>
36 #include <sys/file.h>
37
38 #include <fs/ntfs/ntfs.h>
39 #include <fs/ntfs/ntfs_compr.h>
40
41 #define GET_UINT16(addr) (*((u_int16_t *)(addr)))
42
43 int
44 ntfs_uncompblock(
45 u_int8_t * buf,
46 u_int8_t * cbuf)
47 {
48 u_int32_t ctag;
49 int len, dshift, lmask;
50 int blen, boff;
51 int i, j;
52 int pos, cpos;
53
54 len = GET_UINT16(cbuf) & 0xFFF;
55 dprintf(("ntfs_uncompblock: block length: %d + 3, 0x%x,0x%04x\n",
56 len, len, GET_UINT16(cbuf)));
57
58 if (!(GET_UINT16(cbuf) & 0x8000)) {
59 if ((len + 1) != NTFS_COMPBLOCK_SIZE) {
60 dprintf(("ntfs_uncompblock: len: %x instead of %d\n",
61 len, 0xfff));
62 }
63 memcpy(buf, cbuf + 2, len + 1);
64 bzero(buf + len + 1, NTFS_COMPBLOCK_SIZE - 1 - len);
65 return len + 3;
66 }
67 cpos = 2;
68 pos = 0;
69 while ((cpos < len + 3) && (pos < NTFS_COMPBLOCK_SIZE)) {
70 ctag = cbuf[cpos++];
71 for (i = 0; (i < 8) && (pos < NTFS_COMPBLOCK_SIZE); i++) {
72 if (ctag & 1) {
73 for (j = pos - 1, lmask = 0xFFF, dshift = 12;
74 j >= 0x10; j >>= 1) {
75 dshift--;
76 lmask >>= 1;
77 }
78 boff = -1 - (GET_UINT16(cbuf + cpos) >> dshift);
79 blen = 3 + (GET_UINT16(cbuf + cpos) & lmask);
80 for (j = 0; (j < blen) && (pos < NTFS_COMPBLOCK_SIZE); j++) {
81 buf[pos] = buf[pos + boff];
82 pos++;
83 }
84 cpos += 2;
85 } else {
86 buf[pos++] = cbuf[cpos++];
87 }
88 ctag >>= 1;
89 }
90 }
91 return len + 3;
92 }
93
94 int
95 ntfs_uncompunit(
96 struct ntfsmount * ntmp,
97 u_int8_t * uup,
98 u_int8_t * cup)
99 {
100 int i;
101 int off = 0;
102 int new;
103
104 for (i = 0; i * NTFS_COMPBLOCK_SIZE < ntfs_cntob(NTFS_COMPUNIT_CL); i++) {
105 new = ntfs_uncompblock(uup + i * NTFS_COMPBLOCK_SIZE, cup + off);
106 if (new == 0)
107 return (EINVAL);
108 off += new;
109 }
110 return (0);
111 }
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