ntfs_compr.c revision 67882 
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 67882 2000-10-29 13:57:19Z phk $
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#if defined(__NetBSD__)
39#include <miscfs/specfs/specdev.h>
40#endif
41
42#include <ntfs/ntfs.h>
43#include <ntfs/ntfs_compr.h>
44
45#define GET_UINT16(addr)	(*((u_int16_t *)(addr)))
46
47int
48ntfs_uncompblock(
49	u_int8_t * buf,
50	u_int8_t * cbuf)
51{
52	u_int32_t       ctag;
53	int             len, dshift, lmask;
54	int             blen, boff;
55	int             i, j;
56	int             pos, cpos;
57
58	len = GET_UINT16(cbuf) & 0xFFF;
59	dprintf(("ntfs_uncompblock: block length: %d + 3, 0x%x,0x%04x\n",
60	    len, len, GET_UINT16(cbuf)));
61
62	if (!(GET_UINT16(cbuf) & 0x8000)) {
63		if ((len + 1) != NTFS_COMPBLOCK_SIZE) {
64			dprintf(("ntfs_uncompblock: len: %x instead of %d\n",
65			    len, 0xfff));
66		}
67		memcpy(buf, cbuf + 2, len + 1);
68		bzero(buf + len + 1, NTFS_COMPBLOCK_SIZE - 1 - len);
69		return len + 3;
70	}
71	cpos = 2;
72	pos = 0;
73	while ((cpos < len + 3) && (pos < NTFS_COMPBLOCK_SIZE)) {
74		ctag = cbuf[cpos++];
75		for (i = 0; (i < 8) && (pos < NTFS_COMPBLOCK_SIZE); i++) {
76			if (ctag & 1) {
77				for (j = pos - 1, lmask = 0xFFF, dshift = 12;
78				     j >= 0x10; j >>= 1) {
79					dshift--;
80					lmask >>= 1;
81				}
82				boff = -1 - (GET_UINT16(cbuf + cpos) >> dshift);
83				blen = 3 + (GET_UINT16(cbuf + cpos) & lmask);
84				for (j = 0; (j < blen) && (pos < NTFS_COMPBLOCK_SIZE); j++) {
85					buf[pos] = buf[pos + boff];
86					pos++;
87				}
88				cpos += 2;
89			} else {
90				buf[pos++] = cbuf[cpos++];
91			}
92			ctag >>= 1;
93		}
94	}
95	return len + 3;
96}
97
98int
99ntfs_uncompunit(
100	struct ntfsmount * ntmp,
101	u_int8_t * uup,
102	u_int8_t * cup)
103{
104	int             i;
105	int             off = 0;
106	int             new;
107
108	for (i = 0; i * NTFS_COMPBLOCK_SIZE < ntfs_cntob(NTFS_COMPUNIT_CL); i++) {
109		new = ntfs_uncompblock(uup + i * NTFS_COMPBLOCK_SIZE, cup + off);
110		if (new == 0)
111			return (EINVAL);
112		off += new;
113	}
114	return (0);
115}
116