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#include "rtems-jffs2-config.h"
/*
* JFFS2 -- Journalling Flash File System, Version 2.
*
* Copyright © 2001-2007 Red Hat, Inc.
* Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
* Copyright © 2004 Ferenc Havasi <havasi@inf.u-szeged.hu>,
* University of Szeged, Hungary
* Copyright © 2013 embedded brains GmbH <rtems@embedded-brains.de>
*
* Created by Arjan van de Ven <arjan@infradead.org>
*
* For licensing information, see the file 'LICENCE' in this directory.
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include "compr.h"
/* jffs2_compress:
* @data_in: Pointer to uncompressed data
* @cpage_out: Pointer to returned 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: Lower 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.
* Upper byte will be used later. (soon)
*
* 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.
*/
uint16_t jffs2_compress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
unsigned char *data_in, unsigned char **cpage_out,
uint32_t *datalen, uint32_t *cdatalen)
{
struct super_block *sb = OFNI_BS_2SFFJ(c);
rtems_jffs2_compressor_control *cc = sb->s_compressor_control;
int ret;
if (cc != NULL) {
*cpage_out = &cc->buffer[0];
ret = (*cc->compress)(cc, data_in, *cpage_out, datalen, cdatalen);
} else {
ret = JFFS2_COMPR_NONE;
}
if (ret == JFFS2_COMPR_NONE) {
*cpage_out = data_in;
*datalen = *cdatalen;
}
return ret;
}
int jffs2_decompress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
uint16_t comprtype, unsigned char *cdata_in,
unsigned char *data_out, uint32_t cdatalen, uint32_t datalen)
{
struct super_block *sb = OFNI_BS_2SFFJ(c);
rtems_jffs2_compressor_control *cc = sb->s_compressor_control;
/* Older code had a bug where it would write non-zero 'usercompr'
fields. Deal with it. */
if ((comprtype & 0xff) <= JFFS2_COMPR_ZLIB)
comprtype &= 0xff;
switch (comprtype & 0xff) {
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;
default:
if (cc != NULL) {
return (*cc->decompress)(cc, comprtype, cdata_in, data_out, cdatalen, datalen);
} else {
return -EIO;
}
}
return 0;
}
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