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/*
* JFFS2 -- Journalling Flash File System, Version 2.
*
* Copyright (C) 2001 Red Hat, Inc.
*
* Created by Arjan van de Ven <arjanv@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.
*
* $Id: compr.c,v 1.17 2001/09/23 09:56:46 dwmw2 Exp $
*
*/
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/jffs2.h>
int zlib_compress(unsigned char *data_in, unsigned char *cpage_out, __u32 *sourcelen, __u32 *dstlen);
void zlib_decompress(unsigned char *data_in, unsigned char *cpage_out, __u32 srclen, __u32 destlen);
int rtime_compress(unsigned char *data_in, unsigned char *cpage_out, __u32 *sourcelen, __u32 *dstlen);
void rtime_decompress(unsigned char *data_in, unsigned char *cpage_out, __u32 srclen, __u32 destlen);
int rubinmips_compress(unsigned char *data_in, unsigned char *cpage_out, __u32 *sourcelen, __u32 *dstlen);
void rubinmips_decompress(unsigned char *data_in, unsigned char *cpage_out, __u32 srclen, __u32 destlen);
int dynrubin_compress(unsigned char *data_in, unsigned char *cpage_out, __u32 *sourcelen, __u32 *dstlen);
void dynrubin_decompress(unsigned char *data_in, unsigned char *cpage_out, __u32 srclen, __u32 destlen);
/* jffs2_compress:
* @data: Pointer to uncompressed data
* @cdata: Pointer to buffer for compressed data
* @datalen: On entry, holds the amount of data available for compression.
* On exit, expected to hold the amount of data actually compressed.
* @cdatalen: On entry, holds the amount of space available for compressed
* data. On exit, expected to hold the actual size of the compressed
* data.
*
* Returns: Byte to be stored with data indicating compression type used.
* Zero is used to show that the data could not be compressed - the
* compressed version was actually larger than the original.
*
* If the cdata buffer isn't large enough to hold all the uncompressed data,
* jffs2_compress should compress as much as will fit, and should set
* *datalen accordingly to show the amount of data which were compressed.
*/
unsigned char jffs2_compress(unsigned char *data_in, unsigned char *cpage_out,
__u32 *datalen, __u32 *cdatalen)
{
int ret;
ret = zlib_compress(data_in, cpage_out, datalen, cdatalen);
if (!ret) {
return JFFS2_COMPR_ZLIB;
}
#if 0 /* Disabled 23/9/1. With zlib it hardly ever gets a look in */
ret = dynrubin_compress(data_in, cpage_out, datalen, cdatalen);
if (!ret) {
return JFFS2_COMPR_DYNRUBIN;
}
#endif
#if 0 /* Disabled 26/2/1. Obsoleted by dynrubin */
ret = rubinmips_compress(data_in, cpage_out, datalen, cdatalen);
if (!ret) {
return JFFS2_COMPR_RUBINMIPS;
}
#endif
/* rtime does manage to recompress already-compressed data */
ret = rtime_compress(data_in, cpage_out, datalen, cdatalen);
if (!ret) {
return JFFS2_COMPR_RTIME;
}
#if 0
/* We don't need to copy. Let the caller special-case the COMPR_NONE case. */
/* If we get here, no compression is going to work */
/* But we might want to use the fragmentation part -- Arjan */
memcpy(cpage_out,data_in,min(*datalen,*cdatalen));
if (*datalen > *cdatalen)
*datalen = *cdatalen;
#endif
return JFFS2_COMPR_NONE; /* We failed to compress */
}
int jffs2_decompress(unsigned char comprtype, unsigned char *cdata_in,
unsigned char *data_out, __u32 cdatalen, __u32 datalen)
{
switch (comprtype) {
case JFFS2_COMPR_NONE:
/* This should be special-cased elsewhere, but we might as well deal with it */
memcpy(data_out, cdata_in, datalen);
break;
case JFFS2_COMPR_ZERO:
memset(data_out, 0, datalen);
break;
case JFFS2_COMPR_ZLIB:
zlib_decompress(cdata_in, data_out, cdatalen, datalen);
break;
case JFFS2_COMPR_RTIME:
rtime_decompress(cdata_in, data_out, cdatalen, datalen);
break;
case JFFS2_COMPR_RUBINMIPS:
#if 0 /* Disabled 23/9/1 */
rubinmips_decompress(cdata_in, data_out, cdatalen, datalen);
#else
printk(KERN_WARNING "JFFS2: Rubinmips compression encountered but support not compiled in!\n");
#endif
break;
case JFFS2_COMPR_DYNRUBIN:
#if 1 /* Phase this one out */
dynrubin_decompress(cdata_in, data_out, cdatalen, datalen);
#else
printk(KERN_WARNING "JFFS2: Dynrubin compression encountered but support not compiled in!\n");
#endif
break;
default:
printk(KERN_NOTICE "Unknown JFFS2 compression type 0x%02x\n", comprtype);
return -EIO;
}
return 0;
}
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