/* * 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;}