ntfs_compr.c revision 50477 
1/*	$NetBSD: ntfs_compr.c,v 1.2 1999/05/06 15:43:18 christos 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 50477 1999-08-28 01:08:13Z peter $
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#ifdef __FreeBSD__
42#include <machine/clock.h>
43#endif
44
45#include <ntfs/ntfs.h>
46#include <ntfs/ntfs_compr.h>
47
48#define GET_UINT16(addr)	(*((u_int16_t *)(addr)))
49
50int
51ntfs_uncompblock(
52	u_int8_t * buf,
53	u_int8_t * cbuf)
54{
55	u_int32_t       ctag;
56	int             len, dshift, lmask;
57	int             blen, boff;
58	int             i, j;
59	int             pos, cpos;
60
61	len = GET_UINT16(cbuf) & 0xFFF;
62	dprintf(("ntfs_uncompblock: block length: %d + 3, 0x%x,0x%04x\n",
63	    len, len, GET_UINT16(cbuf)));
64
65	if (!(GET_UINT16(cbuf) & 0x8000)) {
66		if ((len + 1) != NTFS_COMPBLOCK_SIZE) {
67			dprintf(("ntfs_uncompblock: len: %x instead of %d\n",
68			    len, 0xfff));
69		}
70		memcpy(buf, cbuf + 2, len + 1);
71		bzero(buf + len + 1, NTFS_COMPBLOCK_SIZE - 1 - len);
72		return len + 3;
73	}
74	cpos = 2;
75	pos = 0;
76	while ((cpos < len + 3) && (pos < NTFS_COMPBLOCK_SIZE)) {
77		ctag = cbuf[cpos++];
78		for (i = 0; (i < 8) && (pos < NTFS_COMPBLOCK_SIZE); i++) {
79			if (ctag & 1) {
80				for (j = pos - 1, lmask = 0xFFF, dshift = 12;
81				     j >= 0x10; j >>= 1) {
82					dshift--;
83					lmask >>= 1;
84				}
85				boff = -1 - (GET_UINT16(cbuf + cpos) >> dshift);
86				blen = 3 + (GET_UINT16(cbuf + cpos) & lmask);
87				for (j = 0; (j < blen) && (pos < NTFS_COMPBLOCK_SIZE); j++) {
88					buf[pos] = buf[pos + boff];
89					pos++;
90				}
91				cpos += 2;
92			} else {
93				buf[pos++] = cbuf[cpos++];
94			}
95			ctag >>= 1;
96		}
97	}
98	return len + 3;
99}
100
101int
102ntfs_uncompunit(
103	struct ntfsmount * ntmp,
104	u_int8_t * uup,
105	u_int8_t * cup)
106{
107	int             i;
108	int             off = 0;
109	int             new;
110
111	for (i = 0; i * NTFS_COMPBLOCK_SIZE < ntfs_cntob(NTFS_COMPUNIT_CL); i++) {
112		new = ntfs_uncompblock(uup + i * NTFS_COMPBLOCK_SIZE, cup + off);
113		if (new == 0)
114			return (EINVAL);
115		off += new;
116	}
117	return (0);
118}
119