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/*
* expand_block_v1.c - LZSA1 block decompressor implementation
*
* Copyright (C) 2019 Emmanuel Marty
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
*
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
/*
* Uses the libdivsufsort library Copyright (c) 2003-2008 Yuta Mori
*
* Inspired by LZ4 by Yann Collet. https://github.com/lz4/lz4
* With help, ideas, optimizations and speed measurements by spke <zxintrospec@gmail.com>
* With ideas from Lizard by Przemyslaw Skibinski and Yann Collet. https://github.com/inikep/lizard
* Also with ideas from smallz4 by Stephan Brumme. https://create.stephan-brumme.com/smallz4/
*
*/
#include <stdlib.h>
#include <string.h>
#include "format.h"
#include "expand_block_v1.h"
#ifdef _MSC_VER
#define FORCE_INLINE __forceinline
#else /* _MSC_VER */
#define FORCE_INLINE __attribute__((always_inline))
#endif /* _MSC_VER */
static inline FORCE_INLINE int lzsa_build_literals_len_v1(const unsigned char **ppInBlock, const unsigned char *pInBlockEnd, unsigned int *nLiterals) {
unsigned int nByte;
const unsigned char *pInBlock = *ppInBlock;
if (pInBlock < pInBlockEnd) {
nByte = *pInBlock++;
(*nLiterals) += nByte;
if (nByte == 250) {
if (pInBlock < pInBlockEnd) {
(*nLiterals) = 256 + ((unsigned int)*pInBlock++);
}
else {
return -1;
}
}
else if (nByte == 249) {
if ((pInBlock + 1) < pInBlockEnd) {
(*nLiterals) = ((unsigned int)*pInBlock++);
(*nLiterals) |= (((unsigned int)*pInBlock++) << 8);
}
else {
return -1;
}
}
*ppInBlock = pInBlock;
return 0;
}
else {
return -1;
}
}
static inline FORCE_INLINE int lzsa_build_match_len_v1(const unsigned char **ppInBlock, const unsigned char *pInBlockEnd, unsigned int *nMatchLen) {
unsigned int nByte;
const unsigned char *pInBlock = *ppInBlock;
if (pInBlock < pInBlockEnd) {
nByte = *pInBlock++;
(*nMatchLen) += nByte;
if (nByte == 239) {
if (pInBlock < pInBlockEnd) {
(*nMatchLen) = 256 + ((unsigned int)*pInBlock++);
}
else {
return -1;
}
}
else if (nByte == 238) {
if ((pInBlock + 1) < pInBlockEnd) {
(*nMatchLen) = ((unsigned int)*pInBlock++);
(*nMatchLen) |= (((unsigned int)*pInBlock++) << 8);
}
else {
return -1;
}
}
*ppInBlock = pInBlock;
return 0;
}
else {
return -1;
}
}
/**
* Decompress one LZSA1 data block
*
* @param pInBlock pointer to compressed data
* @param nBlockSize size of compressed data, in bytes
* @param pOutData pointer to output decompression buffer (previously decompressed bytes + room for decompressing this block)
* @param nOutDataOffset starting index of where to store decompressed bytes in output buffer (and size of previously decompressed bytes)
* @param nBlockMaxSize total size of output decompression buffer, in bytes
*
* @return size of decompressed data in bytes, or -1 for error
*/
int lzsa_decompressor_expand_block_v1(const unsigned char *pInBlock, int nBlockSize, unsigned char *pOutData, int nOutDataOffset, int nBlockMaxSize) {
const unsigned char *pInBlockEnd = pInBlock + nBlockSize;
unsigned char *pCurOutData = pOutData + nOutDataOffset;
const unsigned char *pOutDataEnd = pCurOutData + nBlockMaxSize;
const unsigned char *pOutDataFastEnd = pOutDataEnd - 18;
while (pInBlock < pInBlockEnd) {
const unsigned char token = *pInBlock++;
unsigned int nLiterals = (unsigned int)((token & 0x70) >> 4);
if (nLiterals != LITERALS_RUN_LEN_V1 && (pInBlock + 8) <= pInBlockEnd && pCurOutData < pOutDataFastEnd) {
memcpy(pCurOutData, pInBlock, 8);
pInBlock += nLiterals;
pCurOutData += nLiterals;
}
else {
if (nLiterals == LITERALS_RUN_LEN_V1) {
if (lzsa_build_literals_len_v1(&pInBlock, pInBlockEnd, &nLiterals))
return -1;
}
if (nLiterals != 0) {
if ((pInBlock + nLiterals) <= pInBlockEnd &&
(pCurOutData + nLiterals) <= pOutDataEnd) {
memcpy(pCurOutData, pInBlock, nLiterals);
pInBlock += nLiterals;
pCurOutData += nLiterals;
}
else {
return -1;
}
}
}
if ((pInBlock + 1) < pInBlockEnd) { /* The last token in the block does not include match information */
unsigned int nMatchOffset;
nMatchOffset = ((unsigned int)(*pInBlock++)) ^ 0xff;
if (token & 0x80) {
nMatchOffset |= (((unsigned int)(*pInBlock++)) << 8) ^ 0xff00;
}
nMatchOffset++;
const unsigned char *pSrc = pCurOutData - nMatchOffset;
if (pSrc >= pOutData) {
unsigned int nMatchLen = (unsigned int)(token & 0x0f);
if (nMatchLen != MATCH_RUN_LEN_V1 && nMatchOffset >= 8 && pCurOutData < pOutDataFastEnd && (pSrc + 18) <= pOutDataEnd) {
memcpy(pCurOutData, pSrc, 8);
memcpy(pCurOutData + 8, pSrc + 8, 8);
memcpy(pCurOutData + 16, pSrc + 16, 2);
pCurOutData += (MIN_MATCH_SIZE_V1 + nMatchLen);
}
else {
nMatchLen += MIN_MATCH_SIZE_V1;
if (nMatchLen == (MATCH_RUN_LEN_V1 + MIN_MATCH_SIZE_V1)) {
if (lzsa_build_match_len_v1(&pInBlock, pInBlockEnd, &nMatchLen))
return -1;
if (nMatchLen == 0)
break;
}
if ((pSrc + nMatchLen) <= pOutDataEnd) {
if ((pCurOutData + nMatchLen) <= pOutDataEnd) {
/* Do a deterministic, left to right byte copy instead of memcpy() so as to handle overlaps */
if (nMatchOffset >= 16 && (pCurOutData + nMatchLen) < (pOutDataFastEnd - 15)) {
const unsigned char *pCopySrc = pSrc;
unsigned char *pCopyDst = pCurOutData;
const unsigned char *pCopyEndDst = pCurOutData + nMatchLen;
do {
memcpy(pCopyDst, pCopySrc, 16);
pCopySrc += 16;
pCopyDst += 16;
} while (pCopyDst < pCopyEndDst);
pCurOutData += nMatchLen;
}
else {
while (nMatchLen) {
*pCurOutData++ = *pSrc++;
nMatchLen--;
}
}
}
else {
return -1;
}
}
else {
return -1;
}
}
}
else {
return -1;
}
}
}
return (int)(pCurOutData - (pOutData + nOutDataOffset));
}
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