1/*	$OpenBSD: ntfs_compr.c,v 1.7 2013/11/24 16:02:30 jsing Exp $	*/
2/*	$NetBSD: ntfs_compr.c,v 1.1 2002/12/23 17:38:31 jdolecek Exp $	*/
3
4/*-
5 * Copyright (c) 1998, 1999 Semen Ustimenko
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 *	Id: ntfs_compr.c,v 1.4 1999/05/12 09:42:54 semenu Exp
30 */
31
32#include <sys/param.h>
33#include <sys/systm.h>
34#include <sys/mount.h>
35
36#include <ntfs/ntfs.h>
37#include <ntfs/ntfs_compr.h>
38
39#define GET_UINT16(addr)	(*((u_int16_t *)(addr)))
40
41int
42ntfs_uncompblock(u_int8_t *buf, u_int8_t *cbuf)
43{
44	u_int32_t ctag;
45	int len, dshift, lmask;
46	int blen, boff;
47	int i, j;
48	int pos, cpos;
49
50	len = GET_UINT16(cbuf) & 0xFFF;
51	DPRINTF("ntfs_uncompblock: block length: %d + 3, 0x%x,0x%04x\n",
52	    len, len, GET_UINT16(cbuf));
53
54	if (!(GET_UINT16(cbuf) & 0x8000)) {
55		if ((len + 1) != NTFS_COMPBLOCK_SIZE) {
56			DPRINTF("ntfs_uncompblock: len: %x instead of %d\n",
57			    len, 0xfff);
58		}
59		memcpy(buf, cbuf + 2, len + 1);
60		bzero(buf + len + 1, NTFS_COMPBLOCK_SIZE - 1 - len);
61		return (len + 3);
62	}
63	cpos = 2;
64	pos = 0;
65	while ((cpos < len + 3) && (pos < NTFS_COMPBLOCK_SIZE)) {
66		ctag = cbuf[cpos++];
67		for (i = 0; (i < 8) && (pos < NTFS_COMPBLOCK_SIZE); i++) {
68			if (ctag & 1) {
69				for (j = pos - 1, lmask = 0xFFF, dshift = 12;
70				     j >= 0x10; j >>= 1) {
71					dshift--;
72					lmask >>= 1;
73				}
74				boff = -1 - (GET_UINT16(cbuf + cpos) >> dshift);
75				blen = 3 + (GET_UINT16(cbuf + cpos) & lmask);
76				for (j = 0; (j < blen) &&
77				    (pos < NTFS_COMPBLOCK_SIZE); j++) {
78					buf[pos] = buf[pos + boff];
79					pos++;
80				}
81				cpos += 2;
82			} else {
83				buf[pos++] = cbuf[cpos++];
84			}
85			ctag >>= 1;
86		}
87	}
88	return (len + 3);
89}
90
91int
92ntfs_uncompunit(struct ntfsmount *ntmp, u_int8_t *uup, u_int8_t *cup)
93{
94	int i;
95	int off = 0;
96	int new;
97
98	for (i = 0; i * NTFS_COMPBLOCK_SIZE < ntfs_cntob(NTFS_COMPUNIT_CL);
99	    i++) {
100		new = ntfs_uncompblock(uup + i * NTFS_COMPBLOCK_SIZE,
101		    cup + off);
102		if (new == 0)
103			return (EINVAL);
104		off += new;
105	}
106	return (0);
107}
108