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/*
* LZO decompressor for the Linux kernel. Code borrowed from the lzo
* implementation by Markus Franz Xaver Johannes Oberhumer.
*
* Linux kernel adaptation:
* Copyright (C) 2009
* Albin Tonnerre, Free Electrons <albin.tonnerre@free-electrons.com>
*
* Original code:
* Copyright (C) 1996-2005 Markus Franz Xaver Johannes Oberhumer
* All Rights Reserved.
*
* lzop and the LZO library are free software; you can redistribute them
* and/or modify them under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* 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; see the file COPYING.
* If not, write to the Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Markus F.X.J. Oberhumer
* <markus@oberhumer.com>
* http://www.oberhumer.com/opensource/lzop/
*/
#ifdef STATIC
#include "lzo/lzo1x_decompress.c"
#else
#include <linux/slab.h>
#include <linux/decompress/unlzo.h>
#endif
#include <linux/types.h>
#include <linux/lzo.h>
#include <linux/decompress/mm.h>
#include <linux/compiler.h>
#include <asm/unaligned.h>
static const unsigned char lzop_magic[] = {
0x89, 0x4c, 0x5a, 0x4f, 0x00, 0x0d, 0x0a, 0x1a, 0x0a };
#define LZO_BLOCK_SIZE (256*1024l)
#define HEADER_HAS_FILTER 0x00000800L
STATIC inline int INIT parse_header(u8 *input, u8 *skip)
{
int l;
u8 *parse = input;
u8 level = 0;
u16 version;
/* read magic: 9 first bits */
for (l = 0; l < 9; l++) {
if (*parse++ != lzop_magic[l])
return 0;
}
/* get version (2bytes), skip library version (2),
* 'need to be extracted' version (2) and
* method (1) */
version = get_unaligned_be16(parse);
parse += 7;
if (version >= 0x0940)
level = *parse++;
if (get_unaligned_be32(parse) & HEADER_HAS_FILTER)
parse += 8; /* flags + filter info */
else
parse += 4; /* flags */
/* skip mode and mtime_low */
parse += 8;
if (version >= 0x0940)
parse += 4; /* skip mtime_high */
l = *parse++;
/* don't care about the file name, and skip checksum */
parse += l + 4;
*skip = parse - input;
return 1;
}
STATIC inline int INIT unlzo(u8 *input, int in_len,
int (*fill) (void *, unsigned int),
int (*flush) (void *, unsigned int),
u8 *output, int *posp,
void (*error) (char *x))
{
u8 skip = 0, r = 0;
u32 src_len, dst_len;
size_t tmp;
u8 *in_buf, *in_buf_save, *out_buf;
int ret = -1;
if (output) {
out_buf = output;
} else if (!flush) {
error("NULL output pointer and no flush function provided");
goto exit;
} else {
out_buf = malloc(LZO_BLOCK_SIZE);
if (!out_buf) {
error("Could not allocate output buffer");
goto exit;
}
}
if (input && fill) {
error("Both input pointer and fill function provided, don't know what to do");
goto exit_1;
} else if (input) {
in_buf = input;
} else if (!fill || !posp) {
error("NULL input pointer and missing position pointer or fill function");
goto exit_1;
} else {
in_buf = malloc(lzo1x_worst_compress(LZO_BLOCK_SIZE));
if (!in_buf) {
error("Could not allocate input buffer");
goto exit_1;
}
}
in_buf_save = in_buf;
if (posp)
*posp = 0;
if (fill)
fill(in_buf, lzo1x_worst_compress(LZO_BLOCK_SIZE));
if (!parse_header(input, &skip)) {
error("invalid header");
goto exit_2;
}
in_buf += skip;
if (posp)
*posp = skip;
for (;;) {
/* read uncompressed block size */
dst_len = get_unaligned_be32(in_buf);
in_buf += 4;
/* exit if last block */
if (dst_len == 0) {
if (posp)
*posp += 4;
break;
}
if (dst_len > LZO_BLOCK_SIZE) {
error("dest len longer than block size");
goto exit_2;
}
/* read compressed block size, and skip block checksum info */
src_len = get_unaligned_be32(in_buf);
in_buf += 8;
if (src_len <= 0 || src_len > dst_len) {
error("file corrupted");
goto exit_2;
}
/* decompress */
tmp = dst_len;
/* When the input data is not compressed at all,
* lzo1x_decompress_safe will fail, so call memcpy()
* instead */
if (unlikely(dst_len == src_len))
memcpy(out_buf, in_buf, src_len);
else {
r = lzo1x_decompress_safe((u8 *) in_buf, src_len,
out_buf, &tmp);
if (r != LZO_E_OK || dst_len != tmp) {
error("Compressed data violation");
goto exit_2;
}
}
if (flush)
flush(out_buf, dst_len);
if (output)
out_buf += dst_len;
if (posp)
*posp += src_len + 12;
if (fill) {
in_buf = in_buf_save;
fill(in_buf, lzo1x_worst_compress(LZO_BLOCK_SIZE));
} else
in_buf += src_len;
}
ret = 0;
exit_2:
if (!input)
free(in_buf);
exit_1:
if (!output)
free(out_buf);
exit:
return ret;
}
#define decompress unlzo
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