gzip_wrapper.c revision b552f0092251f472920f73e701bfd7fffe954327 
1/*
2 * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
3 * Phillip Lougher <phillip@lougher.demon.co.uk>
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation; either version 2,
8 * or (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18 *
19 * gzip_wrapper.c
20 */
21
22#include <stdlib.h>
23#include <zlib.h>
24
25int gzip_compress(void **strm, char *d, char *s, int size, int block_size,
26		int *error)
27{
28	int res = 0;
29	z_stream *stream = *strm;
30
31	if(stream == NULL) {
32		if((stream = *strm = malloc(sizeof(z_stream))) == NULL)
33			goto failed;
34
35		stream->zalloc = Z_NULL;
36		stream->zfree = Z_NULL;
37		stream->opaque = 0;
38
39		if((res = deflateInit(stream, 9)) != Z_OK)
40			goto failed;
41	} else if((res = deflateReset(stream)) != Z_OK)
42		goto failed;
43
44	stream->next_in = (unsigned char *) s;
45	stream->avail_in = size;
46	stream->next_out = (unsigned char *) d;
47	stream->avail_out = block_size;
48
49	res = deflate(stream, Z_FINISH);
50	if(res == Z_STREAM_END)
51		/*
52		 * Success, return the compressed size.
53		 */
54		return (int) stream->total_out;
55	if(res == Z_OK)
56		/*
57		 * Output buffer overflow.  Return out of buffer space
58		 */
59		return 0;
60failed:
61	/*
62	 * All other errors return failure, with the compressor
63	 * specific error code in *error
64	 */
65	*error = res;
66	return -1;
67}
68
69
70int gzip_uncompress(char *d, char *s, int size, int block_size, int *error)
71{
72	int res;
73	unsigned long bytes = block_size;
74
75	res = uncompress((unsigned char *) d, &bytes,
76		(const unsigned char *) s, size);
77
78	*error = res;
79	return res == Z_OK ? (int) bytes : -1;
80}
81