aboutsummaryrefslogtreecommitdiff
path: root/compr_zlib.c
blob: 1f946285f04bb722bbe5d9e17404af6434ba482c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright (C) 2001 Red Hat, Inc.
 *
 * Created by David Woodhouse <dwmw2@cambridge.redhat.com>
 *
 * The original JFFS, from which the design for JFFS2 was derived,
 * was designed and implemented by Axis Communications AB.
 *
 * The contents of this file are subject to the Red Hat eCos Public
 * License Version 1.1 (the "Licence"); you may not use this file
 * except in compliance with the Licence.  You may obtain a copy of
 * the Licence at http://www.redhat.com/
 *
 * Software distributed under the Licence is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.
 * See the Licence for the specific language governing rights and
 * limitations under the Licence.
 *
 * The Original Code is JFFS2 - Journalling Flash File System, version 2
 *
 * Alternatively, the contents of this file may be used under the
 * terms of the GNU General Public License version 2 (the "GPL"), in
 * which case the provisions of the GPL are applicable instead of the
 * above.  If you wish to allow the use of your version of this file
 * only under the terms of the GPL and not to allow others to use your
 * version of this file under the RHEPL, indicate your decision by
 * deleting the provisions above and replace them with the notice and
 * other provisions required by the GPL.  If you do not delete the
 * provisions above, a recipient may use your version of this file
 * under either the RHEPL or the GPL.
 */

#define PROGRAM_NAME "compr_zlib"

#include <stdint.h>
#define crc32 __zlib_crc32
#include <zlib.h>
#undef crc32
#include <stdio.h>
#include <asm/types.h>
#include <linux/jffs2.h>
#include "common.h"
#include "compr.h"

/* Plan: call deflate() with avail_in == *sourcelen,
   avail_out = *dstlen - 12 and flush == Z_FINISH.
   If it doesn't manage to finish,	call it again with
   avail_in == 0 and avail_out set to the remaining 12
   bytes for it to clean up.
Q: Is 12 bytes sufficient?
 */
#define STREAM_END_SPACE 12

static int jffs2_zlib_compress(unsigned char *data_in, unsigned char *cpage_out,
		uint32_t *sourcelen, uint32_t *dstlen)
{
	z_stream strm;
	int ret;

	if (*dstlen <= STREAM_END_SPACE)
		return -1;

	strm.zalloc = (void *)0;
	strm.zfree = (void *)0;

	if (Z_OK != deflateInit(&strm, 3)) {
		return -1;
	}
	strm.next_in = data_in;
	strm.total_in = 0;

	strm.next_out = cpage_out;
	strm.total_out = 0;

	while (strm.total_out < *dstlen - STREAM_END_SPACE && strm.total_in < *sourcelen) {
		strm.avail_out = *dstlen - (strm.total_out + STREAM_END_SPACE);
		strm.avail_in = min((unsigned)(*sourcelen-strm.total_in), strm.avail_out);
		ret = deflate(&strm, Z_PARTIAL_FLUSH);
		if (ret != Z_OK) {
			deflateEnd(&strm);
			return -1;
		}
	}
	strm.avail_out += STREAM_END_SPACE;
	strm.avail_in = 0;
	ret = deflate(&strm, Z_FINISH);
	if (ret != Z_STREAM_END) {
		deflateEnd(&strm);
		return -1;
	}
	deflateEnd(&strm);

	if (strm.total_out >= strm.total_in)
		return -1;


	*dstlen = strm.total_out;
	*sourcelen = strm.total_in;
	return 0;
}

static int jffs2_zlib_decompress(unsigned char *data_in, unsigned char *cpage_out,
		uint32_t srclen, uint32_t destlen)
{
	z_stream strm;
	int ret;

	strm.zalloc = (void *)0;
	strm.zfree = (void *)0;

	if (Z_OK != inflateInit(&strm)) {
		return 1;
	}
	strm.next_in = data_in;
	strm.avail_in = srclen;
	strm.total_in = 0;

	strm.next_out = cpage_out;
	strm.avail_out = destlen;
	strm.total_out = 0;

	while((ret = inflate(&strm, Z_FINISH)) == Z_OK)
		;

	inflateEnd(&strm);
	return 0;
}

static struct jffs2_compressor jffs2_zlib_comp = {
	.priority = JFFS2_ZLIB_PRIORITY,
	.name = "zlib",
	.disabled = 0,
	.compr = JFFS2_COMPR_ZLIB,
	.compress = &jffs2_zlib_compress,
	.decompress = &jffs2_zlib_decompress,
};

int jffs2_zlib_init(void)
{
	return jffs2_register_compressor(&jffs2_zlib_comp);
}

void jffs2_zlib_exit(void)
{
	jffs2_unregister_compressor(&jffs2_zlib_comp);
}