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/*
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* JFFS2 -- Journalling Flash File System, Version 2.
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*
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* Copyright (C) 2001 Red Hat, Inc.
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*
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* Created by Arjan van de Ven <arjanv@redhat.com>
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*
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* The original JFFS, from which the design for JFFS2 was derived,
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* was designed and implemented by Axis Communications AB.
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*
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* The contents of this file are subject to the Red Hat eCos Public
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* License Version 1.1 (the "Licence"); you may not use this file
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* except in compliance with the Licence. You may obtain a copy of
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* the Licence at http://www.redhat.com/
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*
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* Software distributed under the Licence is distributed on an "AS IS"
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* basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.
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* See the Licence for the specific language governing rights and
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* limitations under the Licence.
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*
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* The Original Code is JFFS2 - Journalling Flash File System, version 2
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*
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* Alternatively, the contents of this file may be used under the
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* terms of the GNU General Public License version 2 (the "GPL"), in
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* which case the provisions of the GPL are applicable instead of the
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* above. If you wish to allow the use of your version of this file
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* only under the terms of the GPL and not to allow others to use your
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* version of this file under the RHEPL, indicate your decision by
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* deleting the provisions above and replace them with the notice and
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* other provisions required by the GPL. If you do not delete the
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* provisions above, a recipient may use your version of this file
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* under either the RHEPL or the GPL.
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*
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* $Id: compr.c,v 1.1.1.1 2004-04-15 01:11:00 phoenix Exp $
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*
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*/
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/jffs2.h>
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int zlib_compress(unsigned char *data_in, unsigned char *cpage_out, __u32 *sourcelen, __u32 *dstlen);
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void zlib_decompress(unsigned char *data_in, unsigned char *cpage_out, __u32 srclen, __u32 destlen);
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int rtime_compress(unsigned char *data_in, unsigned char *cpage_out, __u32 *sourcelen, __u32 *dstlen);
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void rtime_decompress(unsigned char *data_in, unsigned char *cpage_out, __u32 srclen, __u32 destlen);
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int rubinmips_compress(unsigned char *data_in, unsigned char *cpage_out, __u32 *sourcelen, __u32 *dstlen);
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void rubinmips_decompress(unsigned char *data_in, unsigned char *cpage_out, __u32 srclen, __u32 destlen);
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int dynrubin_compress(unsigned char *data_in, unsigned char *cpage_out, __u32 *sourcelen, __u32 *dstlen);
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void dynrubin_decompress(unsigned char *data_in, unsigned char *cpage_out, __u32 srclen, __u32 destlen);
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/* jffs2_compress:
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* @data: Pointer to uncompressed data
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* @cdata: Pointer to buffer for compressed data
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* @datalen: On entry, holds the amount of data available for compression.
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* On exit, expected to hold the amount of data actually compressed.
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* @cdatalen: On entry, holds the amount of space available for compressed
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* data. On exit, expected to hold the actual size of the compressed
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* data.
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*
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* Returns: Byte to be stored with data indicating compression type used.
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* Zero is used to show that the data could not be compressed - the
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* compressed version was actually larger than the original.
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*
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* If the cdata buffer isn't large enough to hold all the uncompressed data,
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* jffs2_compress should compress as much as will fit, and should set
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* *datalen accordingly to show the amount of data which were compressed.
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*/
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unsigned char jffs2_compress(unsigned char *data_in, unsigned char *cpage_out,
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__u32 *datalen, __u32 *cdatalen)
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{
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int ret;
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ret = zlib_compress(data_in, cpage_out, datalen, cdatalen);
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if (!ret) {
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return JFFS2_COMPR_ZLIB;
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}
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#if 0 /* Disabled 23/9/1. With zlib it hardly ever gets a look in */
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ret = dynrubin_compress(data_in, cpage_out, datalen, cdatalen);
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if (!ret) {
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return JFFS2_COMPR_DYNRUBIN;
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}
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#endif
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#if 0 /* Disabled 26/2/1. Obsoleted by dynrubin */
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ret = rubinmips_compress(data_in, cpage_out, datalen, cdatalen);
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if (!ret) {
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return JFFS2_COMPR_RUBINMIPS;
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}
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#endif
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/* rtime does manage to recompress already-compressed data */
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ret = rtime_compress(data_in, cpage_out, datalen, cdatalen);
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if (!ret) {
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return JFFS2_COMPR_RTIME;
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}
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#if 0
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/* We don't need to copy. Let the caller special-case the COMPR_NONE case. */
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/* If we get here, no compression is going to work */
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/* But we might want to use the fragmentation part -- Arjan */
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memcpy(cpage_out,data_in,min(*datalen,*cdatalen));
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if (*datalen > *cdatalen)
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*datalen = *cdatalen;
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#endif
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return JFFS2_COMPR_NONE; /* We failed to compress */
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}
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int jffs2_decompress(unsigned char comprtype, unsigned char *cdata_in,
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unsigned char *data_out, __u32 cdatalen, __u32 datalen)
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{
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switch (comprtype) {
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case JFFS2_COMPR_NONE:
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/* This should be special-cased elsewhere, but we might as well deal with it */
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memcpy(data_out, cdata_in, datalen);
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break;
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case JFFS2_COMPR_ZERO:
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memset(data_out, 0, datalen);
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break;
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case JFFS2_COMPR_ZLIB:
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zlib_decompress(cdata_in, data_out, cdatalen, datalen);
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break;
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case JFFS2_COMPR_RTIME:
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rtime_decompress(cdata_in, data_out, cdatalen, datalen);
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break;
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case JFFS2_COMPR_RUBINMIPS:
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#if 0 /* Disabled 23/9/1 */
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rubinmips_decompress(cdata_in, data_out, cdatalen, datalen);
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#else
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printk(KERN_WARNING "JFFS2: Rubinmips compression encountered but support not compiled in!\n");
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#endif
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break;
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case JFFS2_COMPR_DYNRUBIN:
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#if 1 /* Phase this one out */
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dynrubin_decompress(cdata_in, data_out, cdatalen, datalen);
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#else
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printk(KERN_WARNING "JFFS2: Dynrubin compression encountered but support not compiled in!\n");
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#endif
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break;
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default:
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printk(KERN_NOTICE "Unknown JFFS2 compression type 0x%02x\n", comprtype);
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return -EIO;
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}
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return 0;
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}
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