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