1219089Spjd/*
2219089Spjd * CDDL HEADER START
3219089Spjd *
4219089Spjd * The contents of this file are subject to the terms of the
5219089Spjd * Common Development and Distribution License (the "License").
6219089Spjd * You may not use this file except in compliance with the License.
7219089Spjd *
8219089Spjd * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9219089Spjd * or http://www.opensolaris.org/os/licensing.
10219089Spjd * See the License for the specific language governing permissions
11219089Spjd * and limitations under the License.
12219089Spjd *
13219089Spjd * When distributing Covered Code, include this CDDL HEADER in each
14219089Spjd * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15219089Spjd * If applicable, add the following below this CDDL HEADER, with the
16219089Spjd * fields enclosed by brackets "[]" replaced with your own identifying
17219089Spjd * information: Portions Copyright [yyyy] [name of copyright owner]
18219089Spjd *
19219089Spjd * CDDL HEADER END
20219089Spjd */
21219089Spjd
22219089Spjd/*
23219089Spjd * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
24219089Spjd * Use is subject to license terms.
25219089Spjd */
26219089Spjd
27219089Spjd/*
28219089Spjd * Zero-length encoding.  This is a fast and simple algorithm to eliminate
29219089Spjd * runs of zeroes.  Each chunk of compressed data begins with a length byte, b.
30219089Spjd * If b < n (where n is the compression parameter) then the next b + 1 bytes
31219089Spjd * are literal values.  If b >= n then the next (256 - b + 1) bytes are zero.
32219089Spjd */
33219089Spjd
34219089Spjdstatic int
35219089Spjdzle_decompress(void *s_start, void *d_start, size_t s_len, size_t d_len, int n)
36219089Spjd{
37219089Spjd	unsigned char *src = s_start;
38219089Spjd	unsigned char *dst = d_start;
39219089Spjd	unsigned char *s_end = src + s_len;
40219089Spjd	unsigned char *d_end = dst + d_len;
41219089Spjd
42219089Spjd	while (src < s_end && dst < d_end) {
43219089Spjd		int len = 1 + *src++;
44219089Spjd		if (len <= n) {
45219089Spjd			while (len-- != 0)
46219089Spjd				*dst++ = *src++;
47219089Spjd		} else {
48219089Spjd			len -= n;
49219089Spjd			while (len-- != 0)
50219089Spjd				*dst++ = 0;
51219089Spjd		}
52219089Spjd	}
53219089Spjd	return (dst == d_end ? 0 : -1);
54219089Spjd}
55