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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 1.1.1.1 2004-04-15 01:11:00 phoenix 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;

}