ntfs_compr.c revision 267654 
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/9.3/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
43int
44ntfs_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
94int
95ntfs_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}
112