1 /*
2 * JFFS2 -- Journalling Flash File System, Version 2.
3 *
4 * Copyright (C) 2001 Red Hat, Inc.
5 *
6 * Created by Arjan van de Ven <arjanv@redhat.com>
7 *
8 * The original JFFS, from which the design for JFFS2 was derived,
9 * was designed and implemented by Axis Communications AB.
10 *
11 * The contents of this file are subject to the Red Hat eCos Public
12 * License Version 1.1 (the "Licence"); you may not use this file
13 * except in compliance with the Licence. You may obtain a copy of
14 * the Licence at http://www.redhat.com/
15 *
16 * Software distributed under the Licence is distributed on an "AS IS"
17 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.
18 * See the Licence for the specific language governing rights and
19 * limitations under the Licence.
20 *
21 * The Original Code is JFFS2 - Journalling Flash File System, version 2
22 *
23 * Alternatively, the contents of this file may be used under the
24 * terms of the GNU General Public License version 2 (the "GPL"), in
25 * which case the provisions of the GPL are applicable instead of the
26 * above. If you wish to allow the use of your version of this file
27 * only under the terms of the GPL and not to allow others to use your
28 * version of this file under the RHEPL, indicate your decision by
29 * deleting the provisions above and replace them with the notice and
30 * other provisions required by the GPL. If you do not delete the
31 * provisions above, a recipient may use your version of this file
32 * under either the RHEPL or the GPL.
33 *
34 * $Id: compr.c,v 1.17 2001/09/23 09:56:46 dwmw2 Exp $
35 *
36 */
37
38 #include <linux/kernel.h>
39 #include <linux/string.h>
40 #include <linux/types.h>
41 #include <linux/errno.h>
42 #include <linux/jffs2.h>
43
44 int zlib_compress(unsigned char *data_in, unsigned char *cpage_out, __u32 *sourcelen, __u32 *dstlen);
45 void zlib_decompress(unsigned char *data_in, unsigned char *cpage_out, __u32 srclen, __u32 destlen);
46 int rtime_compress(unsigned char *data_in, unsigned char *cpage_out, __u32 *sourcelen, __u32 *dstlen);
47 void rtime_decompress(unsigned char *data_in, unsigned char *cpage_out, __u32 srclen, __u32 destlen);
48 int rubinmips_compress(unsigned char *data_in, unsigned char *cpage_out, __u32 *sourcelen, __u32 *dstlen);
49 void rubinmips_decompress(unsigned char *data_in, unsigned char *cpage_out, __u32 srclen, __u32 destlen);
50 int dynrubin_compress(unsigned char *data_in, unsigned char *cpage_out, __u32 *sourcelen, __u32 *dstlen);
51 void dynrubin_decompress(unsigned char *data_in, unsigned char *cpage_out, __u32 srclen, __u32 destlen);
52
53
54 /* jffs2_compress:
55 * @data: Pointer to uncompressed data
56 * @cdata: Pointer to buffer for compressed data
57 * @datalen: On entry, holds the amount of data available for compression.
58 * On exit, expected to hold the amount of data actually compressed.
59 * @cdatalen: On entry, holds the amount of space available for compressed
60 * data. On exit, expected to hold the actual size of the compressed
61 * data.
62 *
63 * Returns: Byte to be stored with data indicating compression type used.
64 * Zero is used to show that the data could not be compressed - the
65 * compressed version was actually larger than the original.
66 *
67 * If the cdata buffer isn't large enough to hold all the uncompressed data,
68 * jffs2_compress should compress as much as will fit, and should set
69 * *datalen accordingly to show the amount of data which were compressed.
70 */
jffs2_compress(unsigned char * data_in,unsigned char * cpage_out,__u32 * datalen,__u32 * cdatalen)71 unsigned char jffs2_compress(unsigned char *data_in, unsigned char *cpage_out,
72 __u32 *datalen, __u32 *cdatalen)
73 {
74 int ret;
75
76 ret = zlib_compress(data_in, cpage_out, datalen, cdatalen);
77 if (!ret) {
78 return JFFS2_COMPR_ZLIB;
79 }
80 #if 0 /* Disabled 23/9/1. With zlib it hardly ever gets a look in */
81 ret = dynrubin_compress(data_in, cpage_out, datalen, cdatalen);
82 if (!ret) {
83 return JFFS2_COMPR_DYNRUBIN;
84 }
85 #endif
86 #if 0 /* Disabled 26/2/1. Obsoleted by dynrubin */
87 ret = rubinmips_compress(data_in, cpage_out, datalen, cdatalen);
88 if (!ret) {
89 return JFFS2_COMPR_RUBINMIPS;
90 }
91 #endif
92 /* rtime does manage to recompress already-compressed data */
93 ret = rtime_compress(data_in, cpage_out, datalen, cdatalen);
94 if (!ret) {
95 return JFFS2_COMPR_RTIME;
96 }
97 #if 0
98 /* We don't need to copy. Let the caller special-case the COMPR_NONE case. */
99 /* If we get here, no compression is going to work */
100 /* But we might want to use the fragmentation part -- Arjan */
101 memcpy(cpage_out,data_in,min(*datalen,*cdatalen));
102 if (*datalen > *cdatalen)
103 *datalen = *cdatalen;
104 #endif
105 return JFFS2_COMPR_NONE; /* We failed to compress */
106
107 }
108
109
jffs2_decompress(unsigned char comprtype,unsigned char * cdata_in,unsigned char * data_out,__u32 cdatalen,__u32 datalen)110 int jffs2_decompress(unsigned char comprtype, unsigned char *cdata_in,
111 unsigned char *data_out, __u32 cdatalen, __u32 datalen)
112 {
113 switch (comprtype) {
114 case JFFS2_COMPR_NONE:
115 /* This should be special-cased elsewhere, but we might as well deal with it */
116 memcpy(data_out, cdata_in, datalen);
117 break;
118
119 case JFFS2_COMPR_ZERO:
120 memset(data_out, 0, datalen);
121 break;
122
123 case JFFS2_COMPR_ZLIB:
124 zlib_decompress(cdata_in, data_out, cdatalen, datalen);
125 break;
126
127 case JFFS2_COMPR_RTIME:
128 rtime_decompress(cdata_in, data_out, cdatalen, datalen);
129 break;
130
131 case JFFS2_COMPR_RUBINMIPS:
132 #if 0 /* Disabled 23/9/1 */
133 rubinmips_decompress(cdata_in, data_out, cdatalen, datalen);
134 #else
135 printk(KERN_WARNING "JFFS2: Rubinmips compression encountered but support not compiled in!\n");
136 #endif
137 break;
138 case JFFS2_COMPR_DYNRUBIN:
139 #if 1 /* Phase this one out */
140 dynrubin_decompress(cdata_in, data_out, cdatalen, datalen);
141 #else
142 printk(KERN_WARNING "JFFS2: Dynrubin compression encountered but support not compiled in!\n");
143 #endif
144 break;
145
146 default:
147 printk(KERN_NOTICE "Unknown JFFS2 compression type 0x%02x\n", comprtype);
148 return -EIO;
149 }
150 return 0;
151 }
152