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/*
* JFFS2 -- Journalling Flash File System, Version 2.
*
* Copyright © 2001-2007 Red Hat, Inc.
* Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
*
* Created by David Woodhouse <dwmw2@infradead.org>
*
* For licensing information, see the file 'LICENCE' in this directory.
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <common.h>
#include <linux/kernel.h>
#include <linux/zlib.h>
#include <linux/zutil.h>
#include "nodelist.h"
#include "compr.h"
/* Plan: call deflate() with avail_in == *sourcelen,
avail_out = *dstlen - 12 and flush == Z_FINISH.
If it doesn't manage to finish, call it again with
avail_in == 0 and avail_out set to the remaining 12
bytes for it to clean up.
Q: Is 12 bytes sufficient?
*/
#define STREAM_END_SPACE 12
static struct z_stream_s inf_strm;
static int jffs2_zlib_decompress(unsigned char *data_in,
unsigned char *cpage_out,
uint32_t srclen, uint32_t destlen)
{
int ret;
int wbits = MAX_WBITS;
inf_strm.next_in = data_in;
inf_strm.avail_in = srclen;
inf_strm.total_in = 0;
inf_strm.next_out = cpage_out;
inf_strm.avail_out = destlen;
inf_strm.total_out = 0;
/* If it's deflate, and it's got no preset dictionary, then
we can tell zlib to skip the adler32 check. */
if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
((data_in[0] & 0x0f) == Z_DEFLATED) &&
!(((data_in[0]<<8) + data_in[1]) % 31)) {
jffs2_dbg(2, "inflate skipping adler32\n");
wbits = -((data_in[0] >> 4) + 8);
inf_strm.next_in += 2;
inf_strm.avail_in -= 2;
} else {
/* Let this remain D1 for now -- it should never happen */
jffs2_dbg(1, "inflate not skipping adler32\n");
}
if (Z_OK != zlib_inflateInit2(&inf_strm, wbits)) {
pr_warn("inflateInit failed\n");
return 1;
}
while((ret = zlib_inflate(&inf_strm, Z_FINISH)) == Z_OK)
;
if (ret != Z_STREAM_END) {
pr_notice("inflate returned %d\n", ret);
}
zlib_inflateEnd(&inf_strm);
return 0;
}
static struct jffs2_compressor jffs2_zlib_comp = {
.priority = JFFS2_ZLIB_PRIORITY,
.name = "zlib",
.compr = JFFS2_COMPR_ZLIB,
.decompress = &jffs2_zlib_decompress,
#ifdef JFFS2_ZLIB_DISABLED
.disabled = 1,
#else
.disabled = 0,
#endif
};
int __init jffs2_zlib_init(void)
{
int ret;
inf_strm.workspace = vmalloc(zlib_inflate_workspacesize());
jffs2_dbg(1, "Allocated %d bytes for inflate workspace\n",
zlib_inflate_workspacesize());
ret = jffs2_register_compressor(&jffs2_zlib_comp);
return ret;
}
void jffs2_zlib_exit(void)
{
jffs2_unregister_compressor(&jffs2_zlib_comp);
vfree(inf_strm.workspace);
}
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