/*
* LZ4 Decompressor for Linux kernel
*
* Copyright (C) 2013 LG Electronics Co., Ltd. (http://www.lge.com/)
*
* Based on LZ4 implementation by Yann Collet.
*
* LZ4 - Fast LZ compression algorithm
* Copyright (C) 2011-2012, Yann Collet.
* BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* You can contact the author at :
* - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html
* - LZ4 source repository : http://code.google.com/p/lz4/
*/
#ifndef STATIC
#include <linux/module.h>
#include <linux/kernel.h>
#endif
#include <linux/lz4.h>
#include <asm/unaligned.h>
#include "lz4defs.h"
static int lz4_uncompress(const char *source, char *dest, int osize)
{
const BYTE *ip = (const BYTE *) source;
const BYTE *ref;
BYTE *op = (BYTE *) dest;
BYTE * const oend = op + osize;
BYTE *cpy;
unsigned token;
size_t length;
size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0};
#if LZ4_ARCH64
size_t dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3};
#endif
while (1) {
/* get runlength */
token = *ip++;
length = (token >> ML_BITS);
if (length == RUN_MASK) {
size_t len;
len = *ip++;
for (; len == 255; length += 255)
len = *ip++;
if (unlikely(length > (size_t)(length + len)))
goto _output_error;
length += len;
}
/* copy literals */
cpy = op + length;
if (unlikely(cpy > oend - COPYLENGTH)) {
/*
* Error: not enough place for another match
* (min 4) + 5 literals
*/
if (cpy != oend)
goto _output_error;
memcpy(op, ip, length);
ip += length;
break; /* EOF */
}
LZ4_WILDCOPY(ip, op, cpy);
ip -= (op - cpy);
op = cpy;
/* get offset */
LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip);
ip += 2;
/* Error: offset create reference outside destination buffer */
if (unlikely(ref < (BYTE *const) dest))
goto _output_error;
/* get matchlength */
length = token & ML_MASK;
if (length == ML_MASK) {
for (; *ip == 255; length += 255)
ip++;
if (unlikely(length > (size_t)(length + *ip)))
goto _output_error;
length += *ip++;
}
/* copy repeated sequence */
if (unlikely((op - ref) < STEPSIZE)) {
#if LZ4_ARCH64
size_t dec64 = dec64table[op - ref];
#else
const int dec64 = 0;
#endif
op[0] = ref[0];
op[1] = ref[1];
op[2] = ref[2];
op[3] = ref[3];
op += 4;
ref += 4;
ref -= dec32table[op-ref];
PUT4(ref, op);
op += STEPSIZE - 4;
ref -= dec64;
} else {
LZ4_COPYSTEP(ref, op);
}
cpy = op + length - (STEPSIZE - 4);
if (cpy > (oend - COPYLENGTH)) {
/* Error: request to write beyond destination buffer */
if (cpy > oend)
goto _output_error;
LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
while (op < cpy)
*op++ = *ref++;
op = cpy;
/*
* Check EOF (should never happen, since last 5 bytes
* are supposed to be literals)
*/
if (op == oend)
goto _output_error;
continue;
}
LZ4_SECURECOPY(ref, op, cpy);
op = cpy; /* correction */
}
/* end of decoding */
return (int) (((char *)ip) - source);
/* write overflow error detected */
_output_error:
return -1;
}
static int lz4_uncompress_unknownoutputsize(const char *source, char *dest,
int isize, size_t maxoutputsize)
{
const BYTE *ip = (const BYTE *) source;
const BYTE *const iend = ip + isize;
const BYTE *ref;
BYTE *op = (BYTE *) dest;
BYTE * const oend = op + maxoutputsize;
BYTE *cpy;
size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0};
#if LZ4_ARCH64
size_t dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3};
#endif
/* Main Loop */
while (ip < iend) {
unsigned token;
size_t length;
/* get runlength */
token = *ip++;
length = (token >> ML_BITS);
if (length == RUN_MASK) {
int s = 255;
while ((ip < iend) && (s == 255)) {
s = *ip++;
length += s;
}
}
/* copy literals */
cpy = op + length;
if ((cpy > oend - COPYLENGTH) ||
(ip + length > iend - COPYLENGTH)) {
if (cpy > oend)
goto _output_error;/* writes beyond buffer */
if (ip + length != iend)
goto _output_error;/*
* Error: LZ4 format requires
* to consume all input
* at this stage
*/
memcpy(op, ip, length);
op += length;
break;/* Necessarily EOF, due to parsing restrictions */
}
LZ4_WILDCOPY(ip, op, cpy);
ip -= (op - cpy);
op = cpy;
/* get offset */
LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip);
ip += 2;
if (ref < (BYTE * const) dest)
goto _output_error;
/*
* Error : offset creates reference
* outside of destination buffer
*/
/* get matchlength */
length = (token & ML_MASK);
if (length == ML_MASK) {
while (ip < iend) {
int s = *ip++;
length += s;
if (s == 255)
continue;
break;
}
}
/* copy repeated sequence */
if (unlikely((op - ref) < STEPSIZE)) {
#if LZ4_ARCH64
size_t dec64 = dec64table[op - ref];
#else
const int dec64 = 0;
#endif
op[0] = ref[0];
op[1] = ref[1];
op[2] = ref[2];
op[3] = ref[3];
op += 4;
ref += 4;
ref -= dec32table[op - ref];
PUT4(ref, op);
op += STEPSIZE - 4;
ref -= dec64;
} else {
LZ4_COPYSTEP(ref, op);
}
cpy = op + length - (STEPSIZE-4);
if (cpy > oend - COPYLENGTH) {
if (cpy > oend)
goto _output_error; /* write outside of buf */
LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
while (op < cpy)
*op++ = *ref++;
op = cpy;
/*
* Check EOF (should never happen, since last 5 bytes
* are supposed to be literals)
*/
if (op == oend)
goto _output_error;
continue;
}
LZ4_SECURECOPY(ref, op, cpy);
op = cpy; /* correction */
}
/* end of decoding */
return (int) (((char *) op) - dest);
/* write overflow error detected */
_output_error:
return (int) (-(((char *) ip) - source));
}
int lz4_decompress(const unsigned char *src, size_t *src_len,
unsigned char *dest, size_t actual_dest_len)
{
int ret = -1;
int input_len = 0;
input_len = lz4_uncompress(src, dest, actual_dest_len);
if (input_len < 0)
goto exit_0;
*src_len = input_len;
return 0;
exit_0:
return ret;
}
#ifndef STATIC
EXPORT_SYMBOL(lz4_decompress);
#endif
int lz4_decompress_unknownoutputsize(const unsigned char *src, size_t src_len,
unsigned char *dest, size_t *dest_len)
{
int ret = -1;
int out_len = 0;
out_len = lz4_uncompress_unknownoutputsize(src, dest, src_len,
*dest_len);
if (out_len < 0)
goto exit_0;
*dest_len = out_len;
return 0;
exit_0:
return ret;
}
#ifndef STATIC
EXPORT_SYMBOL(lz4_decompress_unknownoutputsize);
MODULE_LICENSE("Dual BSD/GPL");
MODULE_DESCRIPTION("LZ4 Decompressor");
#endif