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/*
* JFFS2 LZO Compression Interface.
*
* Copyright (C) 2007 Nokia Corporation. All rights reserved.
*
* Author: Richard Purdie <rpurdie@openedhand.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*
*/
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <asm/types.h>
#include <linux/jffs2.h>
#include <lzo/lzo1x.h>
#include "compr.h"
extern int page_size;
static void *lzo_mem;
static void *lzo_compress_buf;
/*
* Note about LZO compression.
*
* We want to use the _999_ compression routine which gives better compression
* rates at the expense of time. Decompression time is unaffected. We might as
* well use the standard lzo library routines for this but they will overflow
* the destination buffer since they don't check the destination size.
*
* We therefore compress to a temporary buffer and copy if it will fit.
*
*/
static int jffs2_lzo_cmpr(unsigned char *data_in, unsigned char *cpage_out,
uint32_t *sourcelen, uint32_t *dstlen)
{
lzo_uint compress_size;
int ret;
ret = lzo1x_999_compress(data_in, *sourcelen, lzo_compress_buf, &compress_size, lzo_mem);
if (ret != LZO_E_OK)
return -1;
if (compress_size > *dstlen)
return -1;
memcpy(cpage_out, lzo_compress_buf, compress_size);
*dstlen = compress_size;
return 0;
}
static int jffs2_lzo_decompress(unsigned char *data_in, unsigned char *cpage_out,
uint32_t srclen, uint32_t destlen)
{
int ret;
lzo_uint dl;
dl = destlen;
ret = lzo1x_decompress_safe(data_in,srclen,cpage_out,&dl,NULL);
if (ret != LZO_E_OK || dl != destlen)
return -1;
return 0;
}
static struct jffs2_compressor jffs2_lzo_comp = {
.priority = JFFS2_LZO_PRIORITY,
.name = "lzo",
.compr = JFFS2_COMPR_LZO,
.compress = &jffs2_lzo_cmpr,
.decompress = &jffs2_lzo_decompress,
.disabled = 1,
};
int jffs2_lzo_init(void)
{
int ret;
lzo_mem = malloc(LZO1X_999_MEM_COMPRESS);
if (!lzo_mem)
return -1;
/* Worse case LZO compression size from their FAQ */
lzo_compress_buf = malloc(page_size + (page_size / 16) + 64 + 3);
if (!lzo_compress_buf) {
free(lzo_mem);
return -1;
}
ret = jffs2_register_compressor(&jffs2_lzo_comp);
if (ret < 0) {
free(lzo_compress_buf);
free(lzo_mem);
}
return ret;
}
void jffs2_lzo_exit(void)
{
jffs2_unregister_compressor(&jffs2_lzo_comp);
free(lzo_compress_buf);
free(lzo_mem);
}
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