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lzsa/src/expand_v2.c

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/*
* expand_v2.c - LZSA2 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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "format.h"
#include "expand_v2.h"
#ifdef _MSC_VER
#define FORCE_INLINE __forceinline
#else /* _MSC_VER */
#define FORCE_INLINE __attribute__((always_inline))
#endif /* _MSC_VER */
static inline FORCE_INLINE unsigned int lzsa_get_nibble_v2(const unsigned char **ppInBlock, const unsigned char *pInBlockEnd, int *nCurNibbles, unsigned char *nibbles) {
unsigned int nValue;
if ((*nCurNibbles ^= 1) != 0) {
const unsigned char *pInBlock = *ppInBlock;
if (pInBlock >= pInBlockEnd) return -1;
(*nibbles) = *pInBlock++;
*ppInBlock = pInBlock;
}
nValue = ((unsigned int)((*nibbles) & 0xf0)) >> 4;
(*nibbles) <<= 4;
return nValue;
}
static inline FORCE_INLINE int lzsa_expand_literals_slow_v2(const unsigned char **ppInBlock, const unsigned char *pInBlockEnd, unsigned int nLiterals, int *nCurNibbles, unsigned char *nibbles,
unsigned char **ppCurOutData, const unsigned char *pOutDataEnd) {
const unsigned char *pInBlock = *ppInBlock;
unsigned char *pCurOutData = *ppCurOutData;
if (nLiterals == LITERALS_RUN_LEN_V2) {
nLiterals += lzsa_get_nibble_v2(&pInBlock, pInBlockEnd, nCurNibbles, nibbles);
if (nLiterals == (LITERALS_RUN_LEN_V2 + 15)) {
if (pInBlock < pInBlockEnd) {
nLiterals = ((unsigned int)*pInBlock++);
if (nLiterals == 0) {
if ((pInBlock + 1) < pInBlockEnd) {
nLiterals = ((unsigned int)*pInBlock++);
nLiterals |= (((unsigned int)*pInBlock++) << 8);
}
else {
return -1;
}
}
}
else {
return -1;
}
}
}
if (nLiterals != 0) {
if ((pInBlock + nLiterals) <= pInBlockEnd &&
(pCurOutData + nLiterals) <= pOutDataEnd) {
memcpy(pCurOutData, pInBlock, nLiterals);
pInBlock += nLiterals;
pCurOutData += nLiterals;
}
else {
return -1;
}
}
*ppInBlock = pInBlock;
*ppCurOutData = pCurOutData;
return 0;
}
static inline FORCE_INLINE int lzsa_expand_match_slow_v2(const unsigned char **ppInBlock, const unsigned char *pInBlockEnd, const unsigned char *pSrc, unsigned int nMatchLen, int *nCurNibbles, unsigned char *nibbles,
unsigned char **ppCurOutData, const unsigned char *pOutDataEnd, const unsigned char *pOutDataFastEnd) {
const unsigned char *pInBlock = *ppInBlock;
unsigned char *pCurOutData = *ppCurOutData;
nMatchLen += MIN_MATCH_SIZE_V2;
if (nMatchLen == (MATCH_RUN_LEN_V2 + MIN_MATCH_SIZE_V2)) {
nMatchLen += lzsa_get_nibble_v2(&pInBlock, pInBlockEnd, nCurNibbles, nibbles);
if (nMatchLen == (MATCH_RUN_LEN_V2 + MIN_MATCH_SIZE_V2 + 15)) {
if (pInBlock < pInBlockEnd) {
nMatchLen = ((unsigned int)*pInBlock++);
if (nMatchLen == 0) {
if ((pInBlock + 1) < pInBlockEnd) {
nMatchLen = ((unsigned int)*pInBlock++);
nMatchLen |= (((unsigned int)*pInBlock++) << 8);
}
else {
return -1;
}
}
}
else {
return -1;
}
}
}
if ((pCurOutData + nMatchLen) <= pOutDataEnd) {
/* Do a deterministic, left to right byte copy instead of memcpy() so as to handle overlaps */
if ((pCurOutData - pSrc) >= 8 && (pCurOutData + nMatchLen) < (pOutDataFastEnd - 15)) {
const unsigned char *pCopySrc = pSrc;
unsigned char *pCopyDst = pCurOutData;
const unsigned char *pCopyEndDst = pCurOutData + nMatchLen;
do {
memcpy(pCopyDst, pCopySrc, 8);
memcpy(pCopyDst + 8, pCopySrc + 8, 8);
pCopySrc += 16;
pCopyDst += 16;
} while (pCopyDst < pCopyEndDst);
pCurOutData += nMatchLen;
}
else {
while (nMatchLen >= 4) {
*pCurOutData++ = *pSrc++;
*pCurOutData++ = *pSrc++;
*pCurOutData++ = *pSrc++;
*pCurOutData++ = *pSrc++;
nMatchLen -= 4;
}
while (nMatchLen) {
*pCurOutData++ = *pSrc++;
nMatchLen--;
}
}
}
else {
return -1;
}
*ppInBlock = pInBlock;
*ppCurOutData = pCurOutData;
return 0;
}
/**
* Decompress one LZSA2 data block
*
* @param pInBlock pointer to compressed data
* @param nInBlockSize 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_expand_block_v2(const unsigned char *pInBlock, int nBlockSize, unsigned char *pOutData, int nOutDataOffset, int nBlockMaxSize) {
const unsigned char *pInBlockEnd = pInBlock + nBlockSize;
const unsigned char *pInBlockFastEnd = pInBlock + nBlockSize - 8;
unsigned char *pCurOutData = pOutData + nOutDataOffset;
const unsigned char *pOutDataEnd = pCurOutData + nBlockMaxSize;
const unsigned char *pOutDataFastEnd = pOutDataEnd - 20;
int nCurNibbles = 0;
unsigned char nibbles;
int nMatchOffset = 0;
/* Fast loop */
while (pInBlock < pInBlockFastEnd && pCurOutData < pOutDataFastEnd) {
const unsigned char token = *pInBlock++;
unsigned int nLiterals = (unsigned int)((token & 0x18) >> 3);
if (nLiterals < LITERALS_RUN_LEN_V2) {
memcpy(pCurOutData, pInBlock, 8);
pInBlock += nLiterals;
pCurOutData += nLiterals;
}
else {
if (lzsa_expand_literals_slow_v2(&pInBlock, pInBlockEnd, nLiterals, &nCurNibbles, &nibbles, &pCurOutData, pOutDataEnd))
return -1;
}
if ((pInBlock + 1) < pInBlockEnd) { /* The last token in the block does not include match information */
unsigned char nOffsetMode = token & 0xc0;
switch (nOffsetMode) {
case 0x00:
/* 5 bit offset */
nMatchOffset = (unsigned int)lzsa_get_nibble_v2(&pInBlock, pInBlockEnd, &nCurNibbles, &nibbles);
nMatchOffset |= ((token & 0x20) >> 1);
nMatchOffset |= 0xffffffe0;
break;
case 0x40:
/* 9 bit offset */
nMatchOffset = (unsigned int)(*pInBlock++);
nMatchOffset |= (((unsigned int)(token & 0x20)) << 3);
nMatchOffset |= 0xfffffe00;
break;
case 0x80:
/* 13 bit offset */
nMatchOffset = (unsigned int)(*pInBlock++);
nMatchOffset |= (lzsa_get_nibble_v2(&pInBlock, pInBlockEnd, &nCurNibbles, &nibbles) << 8);
nMatchOffset |= (((unsigned int)(token & 0x20)) << 7);
nMatchOffset |= 0xffffe000;
nMatchOffset -= 512;
break;
default:
/* Check if this is a 16 bit offset or a rep-match */
if ((token & 0x20) == 0) {
/* 16 bit offset */
nMatchOffset = (unsigned int)(*pInBlock++);
nMatchOffset |= (((unsigned int)(*pInBlock++)) << 8);
nMatchOffset |= 0xffff0000;
}
break;
}
const unsigned char *pSrc = pCurOutData + nMatchOffset;
if (pSrc >= pOutData) {
unsigned int nMatchLen = (unsigned int)(token & 0x07);
if (nMatchLen < MATCH_RUN_LEN_V2 && nMatchOffset >= 8 && pCurOutData < pOutDataFastEnd) {
memcpy(pCurOutData, pSrc, 8);
memcpy(pCurOutData + 8, pSrc + 8, 4);
pCurOutData += (MIN_MATCH_SIZE_V2 + nMatchLen);
}
else {
if (lzsa_expand_match_slow_v2(&pInBlock, pInBlockEnd, pSrc, nMatchLen, &nCurNibbles, &nibbles, &pCurOutData, pOutDataEnd, pOutDataFastEnd))
return -1;
}
}
else {
return -1;
}
}
}
/* Slow loop for the remainder of the buffer */
while (pInBlock < pInBlockEnd) {
const unsigned char token = *pInBlock++;
unsigned int nLiterals = (unsigned int)((token & 0x18) >> 3);
if (lzsa_expand_literals_slow_v2(&pInBlock, pInBlockEnd, nLiterals, &nCurNibbles, &nibbles, &pCurOutData, pOutDataEnd))
return -1;
if ((pInBlock + 1) < pInBlockEnd) { /* The last token in the block does not include match information */
unsigned char nOffsetMode = token & 0xc0;
switch (nOffsetMode) {
case 0x00:
/* 5 bit offset */
nMatchOffset = (unsigned int)lzsa_get_nibble_v2(&pInBlock, pInBlockEnd, &nCurNibbles, &nibbles);
nMatchOffset |= ((token & 0x20) >> 1);
nMatchOffset |= 0xffffffe0;
break;
case 0x40:
/* 9 bit offset */
nMatchOffset = (unsigned int)(*pInBlock++);
nMatchOffset |= (((unsigned int)(token & 0x20)) << 3);
nMatchOffset |= 0xfffffe00;
break;
case 0x80:
/* 13 bit offset */
nMatchOffset = (unsigned int)(*pInBlock++);
nMatchOffset |= (lzsa_get_nibble_v2(&pInBlock, pInBlockEnd, &nCurNibbles, &nibbles) << 8);
nMatchOffset |= (((unsigned int)(token & 0x20)) << 7);
nMatchOffset |= 0xffffe000;
nMatchOffset -= 512;
break;
default:
/* Check if this is a 16 bit offset or a rep-match */
if ((token & 0x20) == 0) {
/* 16 bit offset */
nMatchOffset = (unsigned int)(*pInBlock++);
nMatchOffset |= (((unsigned int)(*pInBlock++)) << 8);
nMatchOffset |= 0xffff0000;
}
break;
}
const unsigned char *pSrc = pCurOutData + nMatchOffset;
if (pSrc >= pOutData) {
unsigned int nMatchLen = (unsigned int)(token & 0x07);
if (lzsa_expand_match_slow_v2(&pInBlock, pInBlockEnd, pSrc, nMatchLen, &nCurNibbles, &nibbles, &pCurOutData, pOutDataEnd, pOutDataFastEnd))
return -1;
}
else {
return -1;
}
}
}
return (int)(pCurOutData - (pOutData + nOutDataOffset));
}
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