ntfs_compr.c revision 54095 
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: head/sys/fs/ntfs/ntfs_compr.c 54095 1999-12-03 20:37:40Z semenu $
29 */
30
31#include <sys/param.h>
32#include <sys/systm.h>
33#include <sys/namei.h>
34#include <sys/proc.h>
35#include <sys/kernel.h>
36#include <sys/vnode.h>
37#include <sys/mount.h>
38#include <sys/buf.h>
39#include <sys/file.h>
40#include <sys/malloc.h>
41
42#if defined(__NetBSD__)
43#include <miscfs/specfs/specdev.h>
44#endif
45
46#include <ntfs/ntfs.h>
47#include <ntfs/ntfs_compr.h>
48
49#define GET_UINT16(addr)	(*((u_int16_t *)(addr)))
50
51int
52ntfs_uncompblock(
53	u_int8_t * buf,
54	u_int8_t * cbuf)
55{
56	u_int32_t       ctag;
57	int             len, dshift, lmask;
58	int             blen, boff;
59	int             i, j;
60	int             pos, cpos;
61
62	len = GET_UINT16(cbuf) & 0xFFF;
63	dprintf(("ntfs_uncompblock: block length: %d + 3, 0x%x,0x%04x\n",
64	    len, len, GET_UINT16(cbuf)));
65
66	if (!(GET_UINT16(cbuf) & 0x8000)) {
67		if ((len + 1) != NTFS_COMPBLOCK_SIZE) {
68			dprintf(("ntfs_uncompblock: len: %x instead of %d\n",
69			    len, 0xfff));
70		}
71		memcpy(buf, cbuf + 2, len + 1);
72		bzero(buf + len + 1, NTFS_COMPBLOCK_SIZE - 1 - len);
73		return len + 3;
74	}
75	cpos = 2;
76	pos = 0;
77	while ((cpos < len + 3) && (pos < NTFS_COMPBLOCK_SIZE)) {
78		ctag = cbuf[cpos++];
79		for (i = 0; (i < 8) && (pos < NTFS_COMPBLOCK_SIZE); i++) {
80			if (ctag & 1) {
81				for (j = pos - 1, lmask = 0xFFF, dshift = 12;
82				     j >= 0x10; j >>= 1) {
83					dshift--;
84					lmask >>= 1;
85				}
86				boff = -1 - (GET_UINT16(cbuf + cpos) >> dshift);
87				blen = 3 + (GET_UINT16(cbuf + cpos) & lmask);
88				for (j = 0; (j < blen) && (pos < NTFS_COMPBLOCK_SIZE); j++) {
89					buf[pos] = buf[pos + boff];
90					pos++;
91				}
92				cpos += 2;
93			} else {
94				buf[pos++] = cbuf[cpos++];
95			}
96			ctag >>= 1;
97		}
98	}
99	return len + 3;
100}
101
102int
103ntfs_uncompunit(
104	struct ntfsmount * ntmp,
105	u_int8_t * uup,
106	u_int8_t * cup)
107{
108	int             i;
109	int             off = 0;
110	int             new;
111
112	for (i = 0; i * NTFS_COMPBLOCK_SIZE < ntfs_cntob(NTFS_COMPUNIT_CL); i++) {
113		new = ntfs_uncompblock(uup + i * NTFS_COMPBLOCK_SIZE, cup + off);
114		if (new == 0)
115			return (EINVAL);
116		off += new;
117	}
118	return (0);
119}
120