/*
* LZ4 HC - High Compression Mode of LZ4
* Copyright (C) 2011-2015, 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://www.lz4.org
* - LZ4 source repository : https://github.com/lz4/lz4
*
* Changed for kernel usage by:
* Sven Schmidt <[email protected]>
*/
/*-************************************
* Dependencies
**************************************/
#include <linux/lz4.h>
#include "lz4defs.h"
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/string.h> /* memset */
/* *************************************
* Local Constants and types
***************************************/
#define OPTIMAL_ML (int)((ML_MASK - 1) + MINMATCH)
#define HASH_FUNCTION(i) (((i) * 2654435761U) \
>> ((MINMATCH*8) - LZ4HC_HASH_LOG))
#define DELTANEXTU16(p) chainTable[(U16)(p)] /* faster */
static U32 LZ4HC_hashPtr(const void *ptr)
{
return HASH_FUNCTION(LZ4_read32(ptr));
}
/**************************************
* HC Compression
**************************************/
static void LZ4HC_init(LZ4HC_CCtx_internal *hc4, const BYTE *start)
{
memset((void *)hc4->hashTable, 0, sizeof(hc4->hashTable));
memset(hc4->chainTable, 0xFF, sizeof(hc4->chainTable));
hc4->nextToUpdate = 64 * KB;
hc4->base = start - 64 * KB;
hc4->end = start;
hc4->dictBase = start - 64 * KB;
hc4->dictLimit = 64 * KB;
hc4->lowLimit = 64 * KB;
}
/* Update chains up to ip (excluded) */
static FORCE_INLINE void LZ4HC_Insert(LZ4HC_CCtx_internal *hc4,
const BYTE *ip)
{
U16 * const chainTable = hc4->chainTable;
U32 * const hashTable = hc4->hashTable;
const BYTE * const base = hc4->base;
U32 const target = (U32)(ip - base);
U32 idx = hc4->nextToUpdate;
while (idx < target) {
U32 const h = LZ4HC_hashPtr(base + idx);
size_t delta = idx - hashTable[h];
if (delta > MAX_DISTANCE)
delta = MAX_DISTANCE;
DELTANEXTU16(idx) = (U16)delta;
hashTable[h] = idx;
idx++;
}
hc4->nextToUpdate = target;
}
static FORCE_INLINE int LZ4HC_InsertAndFindBestMatch(
LZ4HC_CCtx_internal *hc4, /* Index table will be updated */
const BYTE *ip,
const BYTE * const iLimit,
const BYTE **matchpos,
const int maxNbAttempts)
{
U16 * const chainTable = hc4->chainTable;
U32 * const HashTable = hc4->hashTable;
const BYTE * const base = hc4->base;
const BYTE * const dictBase = hc4->dictBase;
const U32 dictLimit = hc4->dictLimit;
const U32 lowLimit = (hc4->lowLimit + 64 * KB > (U32)(ip - base))
? hc4->lowLimit
: (U32)(ip - base) - (64 * KB - 1);
U32 matchIndex;
int nbAttempts = maxNbAttempts;
size_t ml = 0;
/* HC4 match finder */
LZ4HC_Insert(hc4, ip);
matchIndex = HashTable[LZ4HC_hashPtr(ip)];
while ((matchIndex >= lowLimit)
&& (nbAttempts)) {
nbAttempts--;
if (matchIndex >= dictLimit) {
const BYTE * const match = base + matchIndex;
if (*(match + ml) == *(ip + ml)
&& (LZ4_read32(match) == LZ4_read32(ip))) {
size_t const mlt = LZ4_count(ip + MINMATCH,
match + MINMATCH, iLimit) + MINMATCH;
if (mlt > ml) {
ml = mlt;
*matchpos = match;
}
}
} else {
const BYTE * const match = dictBase + matchIndex;
if (LZ4_read32(match) == LZ4_read32(ip)) {
size_t mlt;
const BYTE *vLimit = ip
+ (dictLimit - matchIndex);
if (vLimit > iLimit)
vLimit = iLimit;
mlt = LZ4_count(ip + MINMATCH,
match + MINMATCH, vLimit) + MINMATCH;
if ((ip + mlt == vLimit)
&& (vLimit < iLimit))
mlt += LZ4_count(ip + mlt,
base + dictLimit,
iLimit);
if (mlt > ml) {
/* virtual matchpos */
ml = mlt;
*matchpos = base + matchIndex;
}
}
}
matchIndex -= DELTANEXTU16(matchIndex);
}
return (int)ml;
}
static FORCE_INLINE int LZ4HC_InsertAndGetWiderMatch(
LZ4HC_CCtx_internal *hc4,
const BYTE * const ip,
const BYTE * const iLowLimit,
const BYTE * const iHighLimit,
int longest,
const BYTE **matchpos,
const BYTE **startpos,
const int maxNbAttempts)
{
U16 * const chainTable = hc4->chainTable;
U32 * const HashTable = hc4->hashTable;
const BYTE * const base = hc4->base;
const U32 dictLimit = hc4->dictLimit;
const BYTE * const lowPrefixPtr = base + dictLimit;
const U32 lowLimit = (hc4->lowLimit + 64 * KB > (U32)(ip - base))
? hc4->lowLimit
: (U32)(ip - base) - (64 * KB - 1);
const BYTE * const dictBase = hc4->dictBase;
U32 matchIndex;
int nbAttempts = maxNbAttempts;
int delta = (int)(ip - iLowLimit);
/* First Match */
LZ4HC_Insert(hc4, ip);
matchIndex = HashTable[LZ4HC_hashPtr(ip)];
while ((matchIndex >= lowLimit)
&& (nbAttempts)) {
nbAttempts--;
if (matchIndex >= dictLimit) {
const BYTE *matchPtr = base + matchIndex;
if (*(iLowLimit + longest)
== *(matchPtr - delta + longest)) {
if (LZ4_read32(matchPtr) == LZ4_read32(ip)) {
int mlt = MINMATCH + LZ4_count(
ip + MINMATCH,
matchPtr + MINMATCH,
iHighLimit);
int back = 0;
while ((ip + back > iLowLimit)
&& (matchPtr + back > lowPrefixPtr)
&& (ip[back - 1] == matchPtr[back - 1]))
back--;
mlt -= back;
if (mlt > longest) {
longest = (int)mlt;
*matchpos = matchPtr + back;
*startpos = ip + back;
}
}
}
} else {
const BYTE * const matchPtr = dictBase + matchIndex;
if (LZ4_read32(matchPtr) == LZ4_read32(ip)) {
size_t mlt;
int back = 0;
const BYTE *vLimit = ip + (dictLimit - matchIndex);
if (vLimit > iHighLimit)
vLimit = iHighLimit;
mlt = LZ4_count(ip + MINMATCH,
matchPtr + MINMATCH, vLimit) + MINMATCH;
if ((ip + mlt == vLimit) && (vLimit < iHighLimit))
mlt += LZ4_count(ip + mlt, base + dictLimit,
iHighLimit);
while ((ip + back > iLowLimit)
&& (matchIndex + back > lowLimit)
&& (ip[back - 1] == matchPtr[back - 1]))
back--;
mlt -= back;
if ((int)mlt > longest) {
longest = (int)mlt;
*matchpos = base + matchIndex + back;
*startpos = ip + back;
}
}
}
matchIndex -= DELTANEXTU16(matchIndex);
}
return longest;
}
static FORCE_INLINE int LZ4HC_encodeSequence(
const BYTE **ip,
BYTE **op,
const BYTE **anchor,
int matchLength,
const BYTE * const match,
limitedOutput_directive limitedOutputBuffer,
BYTE *oend)
{
int length;
BYTE *token;
/* Encode Literal length */
length = (int)(*ip - *anchor);
token = (*op)++;
if ((limitedOutputBuffer)
&& ((*op + (length>>8)
+ length + (2 + 1 + LASTLITERALS)) > oend)) {
/* Check output limit */
return 1;
}
if (length >= (int)RUN_MASK) {
int len;
*token = (RUN_MASK<<ML_BITS);
len = length - RUN_MASK;
for (; len > 254 ; len -= 255)
*(*op)++ = 255;
*(*op)++ = (BYTE)len;
} else
*token = (BYTE)(length<<ML_BITS);
/* Copy Literals */
LZ4_wildCopy(*op, *anchor, (*op) + length);
*op += length;
/* Encode Offset */
LZ4_writeLE16(*op, (U16)(*ip - match));
*op += 2;
/* Encode MatchLength */
length = (int)(matchLength - MINMATCH);
if ((limitedOutputBuffer)
&& (*op + (length>>8)
+ (1 + LASTLITERALS) > oend)) {
/* Check output limit */
return 1;
}
if (length >= (int)ML_MASK) {
*token += ML_MASK;
length -= ML_MASK;
for (; length > 509 ; length -= 510) {
*(*op)++ = 255;
*(*op)++ = 255;
}
if (length > 254) {
length -= 255;
*(*op)++ = 255;
}
*(*op)++ = (BYTE)length;
} else
*token += (BYTE)(length);
/* Prepare next loop */
*ip += matchLength;
*anchor = *ip;
return 0;
}
static int LZ4HC_compress_generic(
LZ4HC_CCtx_internal *const ctx,
const char * const source,
char * const dest,
int const inputSize,
int const maxOutputSize,
int compressionLevel,
limitedOutput_directive limit
)
{
const BYTE *ip = (const BYTE *) source;
const BYTE *anchor = ip;
const BYTE * const iend = ip + inputSize;
const BYTE * const mflimit = iend - MFLIMIT;
const BYTE * const matchlimit = (iend - LASTLITERALS);
BYTE *op = (BYTE *) dest;
BYTE * const oend = op + maxOutputSize;
unsigned int maxNbAttempts;
int ml, ml2, ml3, ml0;
const BYTE *ref = NULL;
const BYTE *start2 = NULL;
const BYTE *ref2 = NULL;
const BYTE *start3 = NULL;
const BYTE *ref3 = NULL;
const BYTE *start0;
const BYTE *ref0;
/* init */
if (compressionLevel > LZ4HC_MAX_CLEVEL)
compressionLevel = LZ4HC_MAX_CLEVEL;
if (compressionLevel < 1)
compressionLevel = LZ4HC_DEFAULT_CLEVEL;
maxNbAttempts = 1 << (compressionLevel - 1);
ctx->end += inputSize;
ip++;
/* Main Loop */
while (ip < mflimit) {
ml = LZ4HC_InsertAndFindBestMatch(ctx, ip,
matchlimit, (&ref), maxNbAttempts);
if (!ml) {
ip++;
continue;
}
/* saved, in case we would skip too much */
start0 = ip;
ref0 = ref;
ml0 = ml;
_Search2:
if (ip + ml < mflimit)
ml2 = LZ4HC_InsertAndGetWiderMatch(ctx,
ip + ml - 2, ip + 0,
matchlimit, ml, &ref2,
&start2, maxNbAttempts);
else
ml2 = ml;
if (ml2 == ml) {
/* No better match */
if (LZ4HC_encodeSequence(&ip, &op,
&anchor, ml, ref, limit, oend))
return 0;
continue;
}
if (start0 < ip) {
if (start2 < ip + ml0) {
/* empirical */
ip = start0;
ref = ref0;
ml = ml0;
}
}
/* Here, start0 == ip */
if ((start2 - ip) < 3) {
/* First Match too small : removed */
ml = ml2;
ip = start2;
ref = ref2;
goto _Search2;
}
_Search3:
/*
* Currently we have :
* ml2 > ml1, and
* ip1 + 3 <= ip2 (usually < ip1 + ml1)
*/
if ((start2 - ip) < OPTIMAL_ML) {
int correction;
int new_ml = ml;
if (new_ml > OPTIMAL_ML)
new_ml = OPTIMAL_ML;
if (ip + new_ml > start2 + ml2 - MINMATCH)
new_ml = (int)(start2 - ip) + ml2 - MINMATCH;
correction = new_ml - (int)(start2 - ip);
if (correction > 0) {
start2 += correction;
ref2 += correction;
ml2 -= correction;
}
}
/*
* Now, we have start2 = ip + new_ml,
* with new_ml = min(ml, OPTIMAL_ML = 18)
*/
if (start2 + ml2 < mflimit)
ml3 = LZ4HC_InsertAndGetWiderMatch(ctx,
start2 + ml2 - 3, start2,
matchlimit, ml2, &ref3, &start3,
maxNbAttempts);
else
ml3 = ml2;
if (ml3 == ml2) {
/* No better match : 2 sequences to encode */
/* ip & ref are known; Now for ml */
if (start2 < ip + ml)
ml = (int)(start2 - ip);
/* Now, encode 2 sequences */
if (LZ4HC_encodeSequence(&ip, &op, &anchor,
ml, ref, limit, oend))
return 0;
ip = start2;
if (LZ4HC_encodeSequence(&ip, &op, &anchor,
ml2, ref2, limit, oend))
return 0;
continue;
}
if (start3 < ip + ml + 3) {
/* Not enough space for match 2 : remove it */
if (start3 >= (ip + ml)) {
/* can write Seq1 immediately
* ==> Seq2 is removed,
* so Seq3 becomes Seq1
*/
if (start2 < ip + ml) {
int correction = (int)(ip + ml - start2);
start2 += correction;
ref2 += correction;
ml2 -= correction;
if (ml2 < MINMATCH) {
start2 = start3;
ref2 = ref3;
ml2 = ml3;
}
}
if (LZ4HC_encodeSequence(&ip, &op, &anchor,
ml, ref, limit, oend))
return 0;
ip = start3;
ref = ref3;
ml = ml3;
start0 = start2;
ref0 = ref2;
ml0 = ml2;
goto _Search2;
}
start2 = start3;
ref2 = ref3;
ml2 = ml3;
goto _Search3;
}
/*
* OK, now we have 3 ascending matches;
* let's write at least the first one
* ip & ref are known; Now for ml
*/
if (start2 < ip + ml) {
if ((start2 - ip) < (int)ML_MASK) {
int correction;
if (ml > OPTIMAL_ML)
ml = OPTIMAL_ML;
if (ip + ml > start2 + ml2 - MINMATCH)
ml = (int)(start2 - ip) + ml2 - MINMATCH;
correction = ml - (int)(start2 - ip);
if (correction > 0) {
start2 += correction;
ref2 += correction;
ml2 -= correction;
}
} else
ml = (int)(start2 - ip);
}
if (LZ4HC_encodeSequence(&ip, &op, &anchor, ml,
ref, limit, oend))
return 0;
ip = start2;
ref = ref2;
ml = ml2;
start2 = start3;
ref2 = ref3;
ml2 = ml3;
goto _Search3;
}
/* Encode Last Literals */
{
int lastRun = (int)(iend - anchor);
if ((limit)
&& (((char *)op - dest) + lastRun + 1
+ ((lastRun + 255 - RUN_MASK)/255)
> (U32)maxOutputSize)) {
/* Check output limit */
return 0;
}
if (lastRun >= (int)RUN_MASK) {
*op++ = (RUN_MASK<<ML_BITS);
lastRun -= RUN_MASK;
for (; lastRun > 254 ; lastRun -= 255)
*op++ = 255;
*op++ = (BYTE) lastRun;
} else
*op++ = (BYTE)(lastRun<<ML_BITS);
LZ4_memcpy(op, anchor, iend - anchor);
op += iend - anchor;
}
/* End */
return (int) (((char *)op) - dest);
}
static int LZ4_compress_HC_extStateHC(
void *state,
const char *src,
char *dst,
int srcSize,
int maxDstSize,
int compressionLevel)
{
LZ4HC_CCtx_internal *ctx = &((LZ4_streamHC_t *)state)->internal_donotuse;
if (((size_t)(state)&(sizeof(void *) - 1)) != 0) {
/* Error : state is not aligned
* for pointers (32 or 64 bits)
*/
return 0;
}
LZ4HC_init(ctx, (const BYTE *)src);
if (maxDstSize < LZ4_compressBound(srcSize))
return LZ4HC_compress_generic(ctx, src, dst,
srcSize, maxDstSize, compressionLevel, limitedOutput);
else
return LZ4HC_compress_generic(ctx, src, dst,
srcSize, maxDstSize, compressionLevel, noLimit);
}
int LZ4_compress_HC(const char *src, char *dst, int srcSize,
int maxDstSize, int compressionLevel, void *wrkmem)
{
return LZ4_compress_HC_extStateHC(wrkmem, src, dst,
srcSize, maxDstSize, compressionLevel);
}
EXPORT_SYMBOL(LZ4_compress_HC);
/**************************************
* Streaming Functions
**************************************/
void LZ4_resetStreamHC(LZ4_streamHC_t *LZ4_streamHCPtr, int compressionLevel)
{
LZ4_streamHCPtr->internal_donotuse.base = NULL;
LZ4_streamHCPtr->internal_donotuse.compressionLevel = (unsigned int)compressionLevel;
}
EXPORT_SYMBOL(LZ4_resetStreamHC);
int LZ4_loadDictHC(LZ4_streamHC_t *LZ4_streamHCPtr,
const char *dictionary,
int dictSize)
{
LZ4HC_CCtx_internal *ctxPtr = &LZ4_streamHCPtr->internal_donotuse;
if (dictSize > 64 * KB) {
dictionary += dictSize - 64 * KB;
dictSize = 64 * KB;
}
LZ4HC_init(ctxPtr, (const BYTE *)dictionary);
if (dictSize >= 4)
LZ4HC_Insert(ctxPtr, (const BYTE *)dictionary + (dictSize - 3));
ctxPtr->end = (const BYTE *)dictionary + dictSize;
return dictSize;
}
EXPORT_SYMBOL(LZ4_loadDictHC);
/* compression */
static void LZ4HC_setExternalDict(
LZ4HC_CCtx_internal *ctxPtr,
const BYTE *newBlock)
{
if (ctxPtr->end >= ctxPtr->base + 4) {
/* Referencing remaining dictionary content */
LZ4HC_Insert(ctxPtr, ctxPtr->end - 3);
}
/*
* Only one memory segment for extDict,
* so any previous extDict is lost at this stage
*/
ctxPtr->lowLimit = ctxPtr->dictLimit;
ctxPtr->dictLimit = (U32)(ctxPtr->end - ctxPtr->base);
ctxPtr->dictBase = ctxPtr->base;
ctxPtr->base = newBlock - ctxPtr->dictLimit;
ctxPtr->end = newBlock;
/* match referencing will resume from there */
ctxPtr->nextToUpdate = ctxPtr->dictLimit;
}
static int LZ4_compressHC_continue_generic(
LZ4_streamHC_t *LZ4_streamHCPtr,
const char *source,
char *dest,
int inputSize,
int maxOutputSize,
limitedOutput_directive limit)
{
LZ4HC_CCtx_internal *ctxPtr = &LZ4_streamHCPtr->internal_donotuse;
/* auto - init if forgotten */
if (ctxPtr->base == NULL)
LZ4HC_init(ctxPtr, (const BYTE *) source);
/* Check overflow */
if ((size_t)(ctxPtr->end - ctxPtr->base) > 2 * GB) {
size_t dictSize = (size_t)(ctxPtr->end - ctxPtr->base)
- ctxPtr->dictLimit;
if (dictSize > 64 * KB)
dictSize = 64 * KB;
LZ4_loadDictHC(LZ4_streamHCPtr,
(const char *)(ctxPtr->end) - dictSize, (int)dictSize);
}
/* Check if blocks follow each other */
if ((const BYTE *)source != ctxPtr->end)
LZ4HC_setExternalDict(ctxPtr, (const BYTE *)source);
/* Check overlapping input/dictionary space */
{
const BYTE *sourceEnd = (const BYTE *) source + inputSize;
const BYTE * const dictBegin = ctxPtr->dictBase + ctxPtr->lowLimit;
const BYTE * const dictEnd = ctxPtr->dictBase + ctxPtr->dictLimit;
if ((sourceEnd > dictBegin)
&& ((const BYTE *)source < dictEnd)) {
if (sourceEnd > dictEnd)
sourceEnd = dictEnd;
ctxPtr->lowLimit = (U32)(sourceEnd - ctxPtr->dictBase);
if (ctxPtr->dictLimit - ctxPtr->lowLimit < 4)
ctxPtr->lowLimit = ctxPtr->dictLimit;
}
}
return LZ4HC_compress_generic(ctxPtr, source, dest,
inputSize, maxOutputSize, ctxPtr->compressionLevel, limit);
}
int LZ4_compress_HC_continue(
LZ4_streamHC_t *LZ4_streamHCPtr,
const char *source,
char *dest,
int inputSize,
int maxOutputSize)
{
if (maxOutputSize < LZ4_compressBound(inputSize))
return LZ4_compressHC_continue_generic(LZ4_streamHCPtr,
source, dest, inputSize, maxOutputSize, limitedOutput);
else
return LZ4_compressHC_continue_generic(LZ4_streamHCPtr,
source, dest, inputSize, maxOutputSize, noLimit);
}
EXPORT_SYMBOL(LZ4_compress_HC_continue);
/* dictionary saving */
int LZ4_saveDictHC(
LZ4_streamHC_t *LZ4_streamHCPtr,
char *safeBuffer,
int dictSize)
{
LZ4HC_CCtx_internal *const streamPtr = &LZ4_streamHCPtr->internal_donotuse;
int const prefixSize = (int)(streamPtr->end
- (streamPtr->base + streamPtr->dictLimit));
if (dictSize > 64 * KB)
dictSize = 64 * KB;
if (dictSize < 4)
dictSize = 0;
if (dictSize > prefixSize)
dictSize = prefixSize;
memmove(safeBuffer, streamPtr->end - dictSize, dictSize);
{
U32 const endIndex = (U32)(streamPtr->end - streamPtr->base);
streamPtr->end = (const BYTE *)safeBuffer + dictSize;
streamPtr->base = streamPtr->end - endIndex;
streamPtr->dictLimit = endIndex - dictSize;
streamPtr->lowLimit = endIndex - dictSize;
if (streamPtr->nextToUpdate < streamPtr->dictLimit)
streamPtr->nextToUpdate = streamPtr->dictLimit;
}
return dictSize;
}
EXPORT_SYMBOL(LZ4_saveDictHC);
MODULE_LICENSE("Dual BSD/GPL");
MODULE_DESCRIPTION("LZ4 HC compressor");
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