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Merge pull request #512 from lz4/HC_dict

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In-place unmutable dictionaries for LZ4HC
This commit is contained in:
Yann Collet 2018-04-24 13:18:40 -07:00 committed by GitHub
commit b2637ab7b2
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GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 314 additions and 52 deletions
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12
lib/lz4frame.c
View File

@ -534,12 +534,8 @@ static void LZ4F_applyCDict(void* ctx,
LZ4_resetStream_fast((LZ4_stream_t *)ctx);
LZ4_attach_dictionary((LZ4_stream_t *)ctx, cdict ? cdict->fastCtx : NULL);
} else {
if (cdict) {
memcpy(ctx, cdict->HCCtx, sizeof(*cdict->HCCtx));
LZ4_setCompressionLevel((LZ4_streamHC_t*)ctx, level);
} else {
LZ4_resetStreamHC((LZ4_streamHC_t*)(ctx), level);
}
LZ4_resetStreamHC_fast((LZ4_streamHC_t*)ctx, level);
LZ4_attach_HC_dictionary((LZ4_streamHC_t *)ctx, cdict ? cdict->HCCtx : NULL);
}
}
@ -725,11 +721,11 @@ static int LZ4F_compressBlock_continue(void* ctx, const char* src, char* dst, in
static int LZ4F_compressBlockHC(void* ctx, const char* src, char* dst, int srcSize, int dstCapacity, int level, const LZ4F_CDict* cdict)
{
LZ4F_applyCDict(ctx, cdict, level);
if (cdict) {
LZ4F_applyCDict(ctx, cdict, level);
return LZ4_compress_HC_continue((LZ4_streamHC_t*)ctx, src, dst, srcSize, dstCapacity);
}
return LZ4_compress_HC_extStateHC(ctx, src, dst, srcSize, dstCapacity, level);
return LZ4_compress_HC_extStateHC_fastReset(ctx, src, dst, srcSize, dstCapacity, level);
}
static int LZ4F_compressBlockHC_continue(void* ctx, const char* src, char* dst, int srcSize, int dstCapacity, int level, const LZ4F_CDict* cdict)

223
lib/lz4hc.c
View File

@ -79,21 +79,33 @@
static U32 LZ4HC_hashPtr(const void* ptr) { return HASH_FUNCTION(LZ4_read32(ptr)); }
/*=== Enums ===*/
typedef enum { noDictCtx, usingDictCtx } dictCtx_directive;
/**************************************
* HC Compression
**************************************/
static void LZ4HC_init (LZ4HC_CCtx_internal* hc4, const BYTE* start)
static void LZ4HC_clearTables (LZ4HC_CCtx_internal* hc4)
{
MEM_INIT((void*)hc4->hashTable, 0, sizeof(hc4->hashTable));
MEM_INIT(hc4->chainTable, 0xFF, sizeof(hc4->chainTable));
hc4->nextToUpdate = 64 KB;
hc4->base = start - 64 KB;
}
static void LZ4HC_init (LZ4HC_CCtx_internal* hc4, const BYTE* start)
{
uptrval startingOffset = hc4->end - hc4->base;
if (startingOffset > 1 GB) {
LZ4HC_clearTables(hc4);
startingOffset = 0;
}
startingOffset += 64 KB;
hc4->nextToUpdate = (U32) startingOffset;
hc4->base = start - startingOffset;
hc4->end = start;
hc4->dictBase = start - 64 KB;
hc4->dictLimit = 64 KB;
hc4->lowLimit = 64 KB;
hc4->dictBase = start - startingOffset;
hc4->dictLimit = (U32) startingOffset;
hc4->lowLimit = (U32) startingOffset;
}
@ -198,19 +210,23 @@ LZ4HC_InsertAndGetWiderMatch (
const BYTE** matchpos,
const BYTE** startpos,
const int maxNbAttempts,
const int patternAnalysis)
const int patternAnalysis,
const dictCtx_directive dict)
{
U16* const chainTable = hc4->chainTable;
U32* const HashTable = hc4->hashTable;
const LZ4HC_CCtx_internal * const dictCtx = hc4->dictCtx;
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) - MAX_DISTANCE;
const U32 ipIndex = (U32)(ip - base);
const U32 lowLimit = (hc4->lowLimit + 64 KB > ipIndex) ? hc4->lowLimit : ipIndex - MAX_DISTANCE;
const BYTE* const dictBase = hc4->dictBase;
int const delta = (int)(ip-iLowLimit);
int nbAttempts = maxNbAttempts;
U32 const pattern = LZ4_read32(ip);
U32 matchIndex;
U32 dictMatchIndex;
repeat_state_e repeat = rep_untested;
size_t srcPatternLength = 0;
@ -287,6 +303,37 @@ LZ4HC_InsertAndGetWiderMatch (
} } } }
} /* while ((matchIndex>=lowLimit) && (nbAttempts)) */
if (dict == usingDictCtx && nbAttempts && ipIndex - lowLimit < MAX_DISTANCE) {
size_t const dictEndOffset = dictCtx->end - dictCtx->base;
assert(dictEndOffset <= 1 GB);
dictMatchIndex = dictCtx->hashTable[LZ4HC_hashPtr(ip)];
matchIndex = dictMatchIndex + lowLimit - (U32)dictEndOffset;
while (ipIndex - matchIndex <= MAX_DISTANCE && nbAttempts--) {
const BYTE* const matchPtr = dictCtx->base + dictMatchIndex;
if (LZ4_read32(matchPtr) == pattern) {
int mlt;
int back = 0;
const BYTE* vLimit = ip + (dictEndOffset - dictMatchIndex);
if (vLimit > iHighLimit) vLimit = iHighLimit;
mlt = LZ4_count(ip+MINMATCH, matchPtr+MINMATCH, vLimit) + MINMATCH;
back = delta ? LZ4HC_countBack(ip, matchPtr, iLowLimit, dictCtx->base + dictCtx->dictLimit) : 0;
mlt -= back;
if (mlt > longest) {
longest = mlt;
*matchpos = base + matchIndex + back;
*startpos = ip + back;
}
}
{
U32 const nextOffset = DELTANEXTU16(dictCtx->chainTable, dictMatchIndex);
dictMatchIndex -= nextOffset;
matchIndex -= nextOffset;
}
}
}
return longest;
}
@ -295,13 +342,14 @@ int LZ4HC_InsertAndFindBestMatch(LZ4HC_CCtx_internal* const hc4, /* Index tabl
const BYTE* const ip, const BYTE* const iLimit,
const BYTE** matchpos,
const int maxNbAttempts,
const int patternAnalysis)
const int patternAnalysis,
const dictCtx_directive dict)
{
const BYTE* uselessPtr = ip;
/* note : LZ4HC_InsertAndGetWiderMatch() is able to modify the starting position of a match (*startpos),
* but this won't be the case here, as we define iLowLimit==ip,
* so LZ4HC_InsertAndGetWiderMatch() won't be allowed to search past ip */
return LZ4HC_InsertAndGetWiderMatch(hc4, ip, ip, iLimit, MINMATCH-1, matchpos, &uselessPtr, maxNbAttempts, patternAnalysis);
return LZ4HC_InsertAndGetWiderMatch(hc4, ip, ip, iLimit, MINMATCH-1, matchpos, &uselessPtr, maxNbAttempts, patternAnalysis, dict);
}
@ -384,14 +432,15 @@ LZ4_FORCE_INLINE int LZ4HC_encodeSequence (
return 0;
}
static int LZ4HC_compress_hashChain (
LZ4_FORCE_INLINE int LZ4HC_compress_hashChain (
LZ4HC_CCtx_internal* const ctx,
const char* const source,
char* const dest,
int* srcSizePtr,
int const maxOutputSize,
unsigned maxNbAttempts,
limitedOutput_directive limit
const limitedOutput_directive limit,
const dictCtx_directive dict
)
{
const int inputSize = *srcSizePtr;
@ -423,7 +472,7 @@ static int LZ4HC_compress_hashChain (
/* Main Loop */
while (ip <= mflimit) {
ml = LZ4HC_InsertAndFindBestMatch (ctx, ip, matchlimit, &ref, maxNbAttempts, patternAnalysis);
ml = LZ4HC_InsertAndFindBestMatch (ctx, ip, matchlimit, &ref, maxNbAttempts, patternAnalysis, dict);
if (ml<MINMATCH) { ip++; continue; }
/* saved, in case we would skip too much */
@ -435,7 +484,7 @@ _Search2:
if (ip+ml <= mflimit)
ml2 = LZ4HC_InsertAndGetWiderMatch(ctx,
ip + ml - 2, ip + 0, matchlimit, ml, &ref2, &start2,
maxNbAttempts, patternAnalysis);
maxNbAttempts, patternAnalysis, dict);
else
ml2 = ml;
@ -482,7 +531,7 @@ _Search3:
if (start2 + ml2 <= mflimit)
ml3 = LZ4HC_InsertAndGetWiderMatch(ctx,
start2 + ml2 - 3, start2, matchlimit, ml2, &ref3, &start3,
maxNbAttempts, patternAnalysis);
maxNbAttempts, patternAnalysis, dict);
else
ml3 = ml2;
@ -606,17 +655,19 @@ static int LZ4HC_compress_optimal( LZ4HC_CCtx_internal* ctx,
const char* const source, char* dst,
int* srcSizePtr, int dstCapacity,
int const nbSearches, size_t sufficient_len,
limitedOutput_directive limit, int const fullUpdate);
const limitedOutput_directive limit, int const fullUpdate,
const dictCtx_directive dict);
static int LZ4HC_compress_generic (
LZ4_FORCE_INLINE int LZ4HC_compress_generic_internal (
LZ4HC_CCtx_internal* const ctx,
const char* const src,
char* const dst,
int* const srcSizePtr,
int const dstCapacity,
int cLevel,
limitedOutput_directive limit
const limitedOutput_directive limit,
const dictCtx_directive dict
)
{
typedef enum { lz4hc, lz4opt } lz4hc_strat_e;
@ -641,6 +692,8 @@ static int LZ4HC_compress_generic (
{ lz4opt,8192, LZ4_OPT_NUM }, /* 12==LZ4HC_CLEVEL_MAX */
};
DEBUGLOG(4, "LZ4HC_compress_generic(%p, %p, %d)", ctx, src, *srcSizePtr);
if (limit == limitedDestSize && dstCapacity < 1) return 0; /* Impossible to store anything */
if ((U32)*srcSizePtr > (U32)LZ4_MAX_INPUT_SIZE) return 0; /* Unsupported input size (too large or negative) */
@ -653,22 +706,81 @@ static int LZ4HC_compress_generic (
if (cParam.strat == lz4hc)
return LZ4HC_compress_hashChain(ctx,
src, dst, srcSizePtr, dstCapacity,
cParam.nbSearches, limit);
cParam.nbSearches, limit, dict);
assert(cParam.strat == lz4opt);
return LZ4HC_compress_optimal(ctx,
src, dst, srcSizePtr, dstCapacity,
cParam.nbSearches, cParam.targetLength, limit,
cLevel == LZ4HC_CLEVEL_MAX); /* ultra mode */
cLevel == LZ4HC_CLEVEL_MAX, dict); /* ultra mode */
}
}
static void LZ4HC_setExternalDict(LZ4HC_CCtx_internal* ctxPtr, const BYTE* newBlock);
static int LZ4HC_compress_generic_noDictCtx (
LZ4HC_CCtx_internal* const ctx,
const char* const src,
char* const dst,
int* const srcSizePtr,
int const dstCapacity,
int cLevel,
limitedOutput_directive limit
)
{
assert(ctx->dictCtx == NULL);
return LZ4HC_compress_generic_internal(ctx, src, dst, srcSizePtr, dstCapacity, cLevel, limit, noDictCtx);
}
static int LZ4HC_compress_generic_dictCtx (
LZ4HC_CCtx_internal* const ctx,
const char* const src,
char* const dst,
int* const srcSizePtr,
int const dstCapacity,
int cLevel,
limitedOutput_directive limit
)
{
const size_t position = ctx->end - ctx->base - ctx->lowLimit;
assert(ctx->dictCtx != NULL);
if (position >= 64 KB) {
ctx->dictCtx = NULL;
return LZ4HC_compress_generic_noDictCtx(ctx, src, dst, srcSizePtr, dstCapacity, cLevel, limit);
} else if (position == 0 && *srcSizePtr > 4 KB) {
memcpy(ctx, ctx->dictCtx, sizeof(LZ4HC_CCtx_internal));
LZ4HC_setExternalDict(ctx, (const BYTE *)src);
ctx->compressionLevel = cLevel;
return LZ4HC_compress_generic_noDictCtx(ctx, src, dst, srcSizePtr, dstCapacity, cLevel, limit);
} else {
return LZ4HC_compress_generic_internal(ctx, src, dst, srcSizePtr, dstCapacity, cLevel, limit, usingDictCtx);
}
}
static int LZ4HC_compress_generic (
LZ4HC_CCtx_internal* const ctx,
const char* const src,
char* const dst,
int* const srcSizePtr,
int const dstCapacity,
int cLevel,
limitedOutput_directive limit
)
{
if (ctx->dictCtx == NULL) {
return LZ4HC_compress_generic_noDictCtx(ctx, src, dst, srcSizePtr, dstCapacity, cLevel, limit);
} else {
return LZ4HC_compress_generic_dictCtx(ctx, src, dst, srcSizePtr, dstCapacity, cLevel, limit);
}
}
int LZ4_sizeofStateHC(void) { return sizeof(LZ4_streamHC_t); }
int LZ4_compress_HC_extStateHC (void* state, const char* src, char* dst, int srcSize, int dstCapacity, int compressionLevel)
int LZ4_compress_HC_extStateHC_fastReset (void* state, const char* src, char* dst, int srcSize, int dstCapacity, int compressionLevel)
{
LZ4HC_CCtx_internal* const ctx = &((LZ4_streamHC_t*)state)->internal_donotuse;
if (((size_t)(state)&(sizeof(void*)-1)) != 0) return 0; /* Error : state is not aligned for pointers (32 or 64 bits) */
LZ4_resetStreamHC_fast((LZ4_streamHC_t*)state, compressionLevel);
LZ4HC_init (ctx, (const BYTE*)src);
if (dstCapacity < LZ4_compressBound(srcSize))
return LZ4HC_compress_generic (ctx, src, dst, &srcSize, dstCapacity, compressionLevel, limitedOutput);
@ -676,6 +788,13 @@ int LZ4_compress_HC_extStateHC (void* state, const char* src, char* dst, int src
return LZ4HC_compress_generic (ctx, src, dst, &srcSize, dstCapacity, compressionLevel, noLimit);
}
int LZ4_compress_HC_extStateHC (void* state, const char* src, char* dst, int srcSize, int dstCapacity, int compressionLevel)
{
if (((size_t)(state)&(sizeof(void*)-1)) != 0) return 0; /* Error : state is not aligned for pointers (32 or 64 bits) */
LZ4_resetStreamHC ((LZ4_streamHC_t*)state, compressionLevel);
return LZ4_compress_HC_extStateHC_fastReset(state, src, dst, srcSize, dstCapacity, compressionLevel);
}
int LZ4_compress_HC(const char* src, char* dst, int srcSize, int dstCapacity, int compressionLevel)
{
#if defined(LZ4HC_HEAPMODE) && LZ4HC_HEAPMODE==1
@ -696,6 +815,7 @@ int LZ4_compress_HC(const char* src, char* dst, int srcSize, int dstCapacity, in
int LZ4_compress_HC_destSize(void* LZ4HC_Data, const char* source, char* dest, int* sourceSizePtr, int targetDestSize, int cLevel)
{
LZ4HC_CCtx_internal* const ctx = &((LZ4_streamHC_t*)LZ4HC_Data)->internal_donotuse;
LZ4_resetStreamHC((LZ4_streamHC_t*)LZ4HC_Data, cLevel);
LZ4HC_init(ctx, (const BYTE*) source);
return LZ4HC_compress_generic(ctx, source, dest, sourceSizePtr, targetDestSize, cLevel, limitedDestSize);
}
@ -706,8 +826,16 @@ int LZ4_compress_HC_destSize(void* LZ4HC_Data, const char* source, char* dest, i
* Streaming Functions
**************************************/
/* allocation */
LZ4_streamHC_t* LZ4_createStreamHC(void) { return (LZ4_streamHC_t*)malloc(sizeof(LZ4_streamHC_t)); }
int LZ4_freeStreamHC (LZ4_streamHC_t* LZ4_streamHCPtr) {
LZ4_streamHC_t* LZ4_createStreamHC(void) {
LZ4_streamHC_t* LZ4_streamHCPtr = (LZ4_streamHC_t*)malloc(sizeof(LZ4_streamHC_t));
LZ4_streamHCPtr->internal_donotuse.end = (const BYTE *)(ptrdiff_t)-1;
LZ4_streamHCPtr->internal_donotuse.base = NULL;
LZ4_streamHCPtr->internal_donotuse.dictCtx = NULL;
return LZ4_streamHCPtr;
}
int LZ4_freeStreamHC (LZ4_streamHC_t* LZ4_streamHCPtr) {
DEBUGLOG(4, "LZ4_freeStreamHC(%p)", LZ4_streamHCPtr);
if (!LZ4_streamHCPtr) return 0; /* support free on NULL */
free(LZ4_streamHCPtr);
return 0;
@ -718,7 +846,19 @@ int LZ4_freeStreamHC (LZ4_streamHC_t* LZ4_streamHCPtr) {
void LZ4_resetStreamHC (LZ4_streamHC_t* LZ4_streamHCPtr, int compressionLevel)
{
LZ4_STATIC_ASSERT(sizeof(LZ4HC_CCtx_internal) <= sizeof(size_t) * LZ4_STREAMHCSIZE_SIZET); /* if compilation fails here, LZ4_STREAMHCSIZE must be increased */
DEBUGLOG(4, "LZ4_resetStreamHC(%p, %d)", LZ4_streamHCPtr, compressionLevel);
LZ4_streamHCPtr->internal_donotuse.end = (const BYTE *)(ptrdiff_t)-1;
LZ4_streamHCPtr->internal_donotuse.base = NULL;
LZ4_streamHCPtr->internal_donotuse.dictCtx = NULL;
LZ4_setCompressionLevel(LZ4_streamHCPtr, compressionLevel);
}
void LZ4_resetStreamHC_fast (LZ4_streamHC_t* LZ4_streamHCPtr, int compressionLevel)
{
DEBUGLOG(4, "LZ4_resetStreamHC_fast(%p, %d)", LZ4_streamHCPtr, compressionLevel);
LZ4_streamHCPtr->internal_donotuse.end -= (uptrval)LZ4_streamHCPtr->internal_donotuse.base;
LZ4_streamHCPtr->internal_donotuse.base = NULL;
LZ4_streamHCPtr->internal_donotuse.dictCtx = NULL;
LZ4_setCompressionLevel(LZ4_streamHCPtr, compressionLevel);
}
@ -732,21 +872,27 @@ void LZ4_setCompressionLevel(LZ4_streamHC_t* LZ4_streamHCPtr, int compressionLev
int LZ4_loadDictHC (LZ4_streamHC_t* LZ4_streamHCPtr, const char* dictionary, int dictSize)
{
LZ4HC_CCtx_internal* const ctxPtr = &LZ4_streamHCPtr->internal_donotuse;
DEBUGLOG(4, "LZ4_loadDictHC(%p, %p, %d)", LZ4_streamHCPtr, dictionary, dictSize);
if (dictSize > 64 KB) {
dictionary += dictSize - 64 KB;
dictSize = 64 KB;
}
LZ4HC_init (ctxPtr, (const BYTE*)dictionary);
LZ4HC_clearTables (ctxPtr);
ctxPtr->end = (const BYTE*)dictionary + dictSize;
if (dictSize >= 4) LZ4HC_Insert (ctxPtr, ctxPtr->end-3);
return dictSize;
}
void LZ4_attach_HC_dictionary(LZ4_streamHC_t *working_stream, const LZ4_streamHC_t *dictionary_stream) {
working_stream->internal_donotuse.dictCtx = dictionary_stream != NULL ? &(dictionary_stream->internal_donotuse) : NULL;
}
/* compression */
static void LZ4HC_setExternalDict(LZ4HC_CCtx_internal* ctxPtr, const BYTE* newBlock)
{
DEBUGLOG(4, "LZ4HC_setExternalDict(%p, %p)", ctxPtr, newBlock);
if (ctxPtr->end >= ctxPtr->base + 4) LZ4HC_Insert (ctxPtr, ctxPtr->end-3); /* Referencing remaining dictionary content */
/* Only one memory segment for extDict, so any previous extDict is lost at this stage */
@ -764,6 +910,7 @@ static int LZ4_compressHC_continue_generic (LZ4_streamHC_t* LZ4_streamHCPtr,
limitedOutput_directive limit)
{
LZ4HC_CCtx_internal* const ctxPtr = &LZ4_streamHCPtr->internal_donotuse;
DEBUGLOG(4, "LZ4_compressHC_continue_generic(%p, %p, %d)", LZ4_streamHCPtr, src, *srcSizePtr);
/* auto-init if forgotten */
if (ctxPtr->base == NULL) LZ4HC_init (ctxPtr, (const BYTE*) src);
@ -812,6 +959,7 @@ int LZ4_saveDictHC (LZ4_streamHC_t* LZ4_streamHCPtr, char* safeBuffer, int dictS
{
LZ4HC_CCtx_internal* const streamPtr = &LZ4_streamHCPtr->internal_donotuse;
int const prefixSize = (int)(streamPtr->end - (streamPtr->base + streamPtr->dictLimit));
DEBUGLOG(4, "LZ4_saveDictHC(%p, %p, %d)", LZ4_streamHCPtr, safeBuffer, dictSize);
if (dictSize > 64 KB) dictSize = 64 KB;
if (dictSize < 4) dictSize = 0;
if (dictSize > prefixSize) dictSize = prefixSize;
@ -851,8 +999,8 @@ int LZ4_resetStreamStateHC(void* state, char* inputBuffer)
{
LZ4HC_CCtx_internal *ctx = &((LZ4_streamHC_t*)state)->internal_donotuse;
if ((((size_t)state) & (sizeof(void*)-1)) != 0) return 1; /* Error : pointer is not aligned for pointer (32 or 64 bits) */
LZ4_resetStreamHC((LZ4_streamHC_t*)state, ((LZ4_streamHC_t*)state)->internal_donotuse.compressionLevel);
LZ4HC_init(ctx, (const BYTE*)inputBuffer);
ctx->inputBuffer = inputBuffer;
return 0;
}
@ -860,9 +1008,8 @@ void* LZ4_createHC (const char* inputBuffer)
{
LZ4_streamHC_t* hc4 = (LZ4_streamHC_t*)ALLOC(sizeof(LZ4_streamHC_t));
if (hc4 == NULL) return NULL; /* not enough memory */
LZ4_resetStreamHC(hc4, 0 /* compressionLevel */);
LZ4HC_init (&hc4->internal_donotuse, (const BYTE*)inputBuffer);
assert(sizeof(size_t) == sizeof(void*));
hc4->internal_donotuse.inputBuffer = (void*)(size_t)inputBuffer; /* ugly hack, circumvent -Wcast-qual */
return hc4;
}
@ -884,9 +1031,11 @@ int LZ4_compressHC2_limitedOutput_continue (void* LZ4HC_Data, const char* src, c
char* LZ4_slideInputBufferHC(void* LZ4HC_Data)
{
LZ4HC_CCtx_internal* const hc4 = &((LZ4_streamHC_t*)LZ4HC_Data)->internal_donotuse;
int const dictSize = LZ4_saveDictHC((LZ4_streamHC_t*)LZ4HC_Data, (char*)(hc4->inputBuffer), 64 KB);
return (char*)(hc4->inputBuffer) + dictSize;
LZ4_streamHC_t *ctx = (LZ4_streamHC_t*)LZ4HC_Data;
const BYTE *bufferStart = ctx->internal_donotuse.base + ctx->internal_donotuse.lowLimit;
LZ4_resetStreamHC_fast(ctx, ctx->internal_donotuse.compressionLevel);
/* avoid const char * -> char * conversion warning :( */
return (char *)(uptrval)bufferStart;
}
@ -932,7 +1081,8 @@ typedef struct {
LZ4_FORCE_INLINE LZ4HC_match_t
LZ4HC_FindLongerMatch(LZ4HC_CCtx_internal* const ctx,
const BYTE* ip, const BYTE* const iHighLimit,
int minLen, int nbSearches)
int minLen, int nbSearches,
const dictCtx_directive dict)
{
LZ4HC_match_t match = { 0 , 0 };
const BYTE* matchPtr = NULL;
@ -941,7 +1091,7 @@ LZ4HC_FindLongerMatch(LZ4HC_CCtx_internal* const ctx,
* so LZ4HC_InsertAndGetWiderMatch() won't be allowed to search past ip */
int const matchLength = LZ4HC_InsertAndGetWiderMatch(ctx,
ip, ip, iHighLimit, minLen, &matchPtr, &ip,
nbSearches, 1 /* patternAnalysis */);
nbSearches, 1 /* patternAnalysis */, dict);
if (matchLength <= minLen) return match;
match.len = matchLength;
match.off = (int)(ip-matchPtr);
@ -957,8 +1107,9 @@ static int LZ4HC_compress_optimal (
int dstCapacity,
int const nbSearches,
size_t sufficient_len,
limitedOutput_directive limit,
int const fullUpdate
const limitedOutput_directive limit,
int const fullUpdate,
const dictCtx_directive dict
)
{
#define TRAILING_LITERALS 3
@ -986,7 +1137,7 @@ static int LZ4HC_compress_optimal (
int best_mlen, best_off;
int cur, last_match_pos = 0;
LZ4HC_match_t const firstMatch = LZ4HC_FindLongerMatch(ctx, ip, matchlimit, MINMATCH-1, nbSearches);
LZ4HC_match_t const firstMatch = LZ4HC_FindLongerMatch(ctx, ip, matchlimit, MINMATCH-1, nbSearches, dict);
if (firstMatch.len==0) { ip++; continue; }
if ((size_t)firstMatch.len > sufficient_len) {
@ -1056,10 +1207,10 @@ static int LZ4HC_compress_optimal (
DEBUGLOG(7, "search at rPos:%u", cur);
if (fullUpdate)
newMatch = LZ4HC_FindLongerMatch(ctx, curPtr, matchlimit, MINMATCH-1, nbSearches);
newMatch = LZ4HC_FindLongerMatch(ctx, curPtr, matchlimit, MINMATCH-1, nbSearches, dict);
else
/* only test matches of minimum length; slightly faster, but misses a few bytes */
newMatch = LZ4HC_FindLongerMatch(ctx, curPtr, matchlimit, last_match_pos - cur, nbSearches);
newMatch = LZ4HC_FindLongerMatch(ctx, curPtr, matchlimit, last_match_pos - cur, nbSearches, dict);
if (!newMatch.len) continue;
if ( ((size_t)newMatch.len > sufficient_len)

81
lib/lz4hc.h
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@ -141,35 +141,37 @@ LZ4LIB_API int LZ4_saveDictHC (LZ4_streamHC_t* streamHCPtr, char* safeBuffer, in
#if defined(__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
#include <stdint.h>
typedef struct
typedef struct LZ4HC_CCtx_internal LZ4HC_CCtx_internal;
struct LZ4HC_CCtx_internal
{
uint32_t hashTable[LZ4HC_HASHTABLESIZE];
uint16_t chainTable[LZ4HC_MAXD];
const uint8_t* end; /* next block here to continue on current prefix */
const uint8_t* base; /* All index relative to this position */
const uint8_t* dictBase; /* alternate base for extDict */
void* inputBuffer; /* deprecated */
uint32_t dictLimit; /* below that point, need extDict */
uint32_t lowLimit; /* below that point, no more dict */
uint32_t nextToUpdate; /* index from which to continue dictionary update */
int compressionLevel;
} LZ4HC_CCtx_internal;
const LZ4HC_CCtx_internal* dictCtx;
};
#else
typedef struct
typedef struct LZ4HC_CCtx_internal LZ4HC_CCtx_internal;
struct LZ4HC_CCtx_internal
{
unsigned int hashTable[LZ4HC_HASHTABLESIZE];
unsigned short chainTable[LZ4HC_MAXD];
const unsigned char* end; /* next block here to continue on current prefix */
const unsigned char* base; /* All index relative to this position */
const unsigned char* dictBase; /* alternate base for extDict */
void* inputBuffer; /* deprecated */
unsigned int dictLimit; /* below that point, need extDict */
unsigned int lowLimit; /* below that point, no more dict */
unsigned int nextToUpdate; /* index from which to continue dictionary update */
int compressionLevel;
} LZ4HC_CCtx_internal;
const LZ4HC_CCtx_internal* dictCtx;
};
#endif
@ -206,7 +208,14 @@ LZ4_DEPRECATED("use LZ4_compress_HC_extStateHC() instead") LZ4LIB_API int LZ4_co
LZ4_DEPRECATED("use LZ4_compress_HC_continue() instead") LZ4LIB_API int LZ4_compressHC_continue (LZ4_streamHC_t* LZ4_streamHCPtr, const char* source, char* dest, int inputSize);
LZ4_DEPRECATED("use LZ4_compress_HC_continue() instead") LZ4LIB_API int LZ4_compressHC_limitedOutput_continue (LZ4_streamHC_t* LZ4_streamHCPtr, const char* source, char* dest, int inputSize, int maxOutputSize);
/* Deprecated Streaming functions; should no longer be used */
/* Obsolete streaming functions; degraded functionality; do not use!
*
* In order to perform streaming compression, these functions depended on data
* that is no longer tracked in the state. They have been preserved as well as
* possible: using them will still produce a correct output. However, use of
* LZ4_slideInputBufferHC() will truncate the history of the stream, rather
* than preserve a window-sized chunk of history.
*/
LZ4_DEPRECATED("use LZ4_createStreamHC() instead") LZ4LIB_API void* LZ4_createHC (const char* inputBuffer);
LZ4_DEPRECATED("use LZ4_saveDictHC() instead") LZ4LIB_API char* LZ4_slideInputBufferHC (void* LZ4HC_Data);
LZ4_DEPRECATED("use LZ4_freeStreamHC() instead") LZ4LIB_API int LZ4_freeHC (void* LZ4HC_Data);
@ -266,7 +275,65 @@ int LZ4_compress_HC_continue_destSize(LZ4_streamHC_t* LZ4_streamHCPtr,
*/
void LZ4_setCompressionLevel(LZ4_streamHC_t* LZ4_streamHCPtr, int compressionLevel);
/*! LZ4_resetStreamHC_fast() :
* When an LZ4_streamHC_t is known to be in a internally coherent state,
* it can often be prepared for a new compression with almost no work, only
* sometimes falling back to the full, expensive reset that is always required
* when the stream is in an indeterminate state (i.e., the reset performed by
* LZ4_resetStreamHC()).
*
* LZ4_streamHCs are guaranteed to be in a valid state when:
* - returned from LZ4_createStreamHC()
* - reset by LZ4_resetStreamHC()
* - memset(stream, 0, sizeof(LZ4_streamHC_t))
* - the stream was in a valid state and was reset by LZ4_resetStreamHC_fast()
* - the stream was in a valid state and was then used in any compression call
* that returned success
* - the stream was in an indeterminate state and was used in a compression
* call that fully reset the state (LZ4_compress_HC_extStateHC()) and that
* returned success
*/
void LZ4_resetStreamHC_fast(LZ4_streamHC_t* LZ4_streamHCPtr, int compressionLevel);
/*! LZ4_compress_HC_extStateHC_fastReset() :
* A variant of LZ4_compress_HC_extStateHC().
*
* Using this variant avoids an expensive initialization step. It is only safe
* to call if the state buffer is known to be correctly initialized already
* (see above comment on LZ4_resetStreamHC_fast() for a definition of
* "correctly initialized"). From a high level, the difference is that this
* function initializes the provided state with a call to
* LZ4_resetStreamHC_fast() while LZ4_compress_HC_extStateHC() starts with a
* call to LZ4_resetStreamHC().
*/
int LZ4_compress_HC_extStateHC_fastReset (void* state, const char* src, char* dst, int srcSize, int dstCapacity, int compressionLevel);
/*! LZ4_attach_HC_dictionary() :
* This is an experimental API that allows for the efficient use of a
* static dictionary many times.
*
* Rather than re-loading the dictionary buffer into a working context before
* each compression, or copying a pre-loaded dictionary's LZ4_streamHC_t into a
* working LZ4_streamHC_t, this function introduces a no-copy setup mechanism,
* in which the working stream references the dictionary stream in-place.
*
* Several assumptions are made about the state of the dictionary stream.
* Currently, only streams which have been prepared by LZ4_loadDictHC() should
* be expected to work.
*
* Alternatively, the provided dictionary stream pointer may be NULL, in which
* case any existing dictionary stream is unset.
*
* A dictionary should only be attached to a stream without any history (i.e.,
* a stream that has just been reset).
*
* The dictionary will remain attached to the working stream only for the
* current stream session. Calls to LZ4_resetStreamHC(_fast) will remove the
* dictionary context association from the working stream. The dictionary
* stream (and source buffer) must remain in-place / accessible / unchanged
* through the lifetime of the stream session.
*/
LZ4LIB_API void LZ4_attach_HC_dictionary(LZ4_streamHC_t *working_stream, const LZ4_streamHC_t *dictionary_stream);
#endif /* LZ4_HC_SLO_098092834 */
#endif /* LZ4_HC_STATIC_LINKING_ONLY */

50
tests/fuzzer.c
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@ -446,7 +446,12 @@ static int FUZ_test(U32 seed, U32 nbCycles, const U32 startCycle, const double c
/* Test compression HC using external state */
FUZ_DISPLAYTEST("test LZ4_compress_HC_extStateHC()");
ret = LZ4_compress_HC_extStateHC(stateLZ4HC, block, compressedBuffer, blockSize, (int)compressedBufferSize, compressionLevel);
FUZ_CHECKTEST(ret==0, "LZ4_compress_HC_extStateHC() failed");
FUZ_CHECKTEST(ret==0, "LZ4_compress_HC_extStateHC() failed")
/* Test compression HC using fast reset external state */
FUZ_DISPLAYTEST("test LZ4_compress_HC_extStateHC_fastReset()");
ret = LZ4_compress_HC_extStateHC_fastReset(stateLZ4HC, block, compressedBuffer, blockSize, (int)compressedBufferSize, compressionLevel);
FUZ_CHECKTEST(ret==0, "LZ4_compress_HC_extStateHC_fastReset() failed");
/* Test compression using external state */
FUZ_DISPLAYTEST("test LZ4_compress_fast_extState()");
@ -835,6 +840,49 @@ static int FUZ_test(U32 seed, U32 nbCycles, const U32 startCycle, const double c
FUZ_CHECKTEST(crcCheck!=crcOrig, "LZ4_decompress_safe_usingDict corrupted decoded data");
}
/* Compress HC using external dictionary stream */
FUZ_DISPLAYTEST();
{
LZ4_streamHC_t LZ4_streamHC;
LZ4_resetStreamHC (&LZ4dictHC, compressionLevel);
LZ4_loadDictHC(&LZ4dictHC, dict, dictSize);
LZ4_resetStreamHC (&LZ4_streamHC, compressionLevel);
LZ4_attach_HC_dictionary(&LZ4_streamHC, &LZ4dictHC);
blockContinueCompressedSize = LZ4_compress_HC_continue(&LZ4_streamHC, block, compressedBuffer, blockSize, (int)compressedBufferSize);
FUZ_CHECKTEST(blockContinueCompressedSize==0, "LZ4_compress_HC_continue with ExtDictCtx failed");
FUZ_DISPLAYTEST();
LZ4_resetStreamHC (&LZ4_streamHC, compressionLevel);
LZ4_attach_HC_dictionary(&LZ4_streamHC, &LZ4dictHC);
ret = LZ4_compress_HC_continue(&LZ4_streamHC, block, compressedBuffer, blockSize, blockContinueCompressedSize-1);
FUZ_CHECKTEST(ret>0, "LZ4_compress_HC_continue using ExtDictCtx should fail : one missing byte for output buffer (%i != %i)", ret, blockContinueCompressedSize);
FUZ_DISPLAYTEST();
LZ4_resetStreamHC (&LZ4_streamHC, compressionLevel);
LZ4_attach_HC_dictionary(&LZ4_streamHC, &LZ4dictHC);
ret = LZ4_compress_HC_continue(&LZ4_streamHC, block, compressedBuffer, blockSize, blockContinueCompressedSize);
FUZ_CHECKTEST(ret!=blockContinueCompressedSize, "LZ4_compress_HC_continue using ExtDictCtx size is different (%i != %i)", ret, blockContinueCompressedSize);
FUZ_CHECKTEST(ret<=0, "LZ4_compress_HC_continue using ExtDictCtx should work : enough size available within output buffer");
FUZ_DISPLAYTEST();
LZ4_resetStreamHC_fast (&LZ4_streamHC, compressionLevel);
LZ4_attach_HC_dictionary(&LZ4_streamHC, &LZ4dictHC);
ret = LZ4_compress_HC_continue(&LZ4_streamHC, block, compressedBuffer, blockSize, blockContinueCompressedSize);
FUZ_CHECKTEST(ret!=blockContinueCompressedSize, "LZ4_compress_HC_continue using ExtDictCtx and fast reset size is different (%i != %i)", ret, blockContinueCompressedSize);
FUZ_CHECKTEST(ret<=0, "LZ4_compress_HC_continue using ExtDictCtx and fast reset should work : enough size available within output buffer");
FUZ_DISPLAYTEST();
decodedBuffer[blockSize] = 0;
ret = LZ4_decompress_safe_usingDict(compressedBuffer, decodedBuffer, blockContinueCompressedSize, blockSize, dict, dictSize);
FUZ_CHECKTEST(ret!=blockSize, "LZ4_decompress_safe_usingDict did not regenerate original data");
FUZ_CHECKTEST(decodedBuffer[blockSize], "LZ4_decompress_safe_usingDict overrun specified output buffer size");
{ U32 const crcCheck = XXH32(decodedBuffer, blockSize, 0);
if (crcCheck!=crcOrig) FUZ_findDiff(block, decodedBuffer);
FUZ_CHECKTEST(crcCheck!=crcOrig, "LZ4_decompress_safe_usingDict corrupted decoded data");
}
}
/* Compress HC continue destSize */
FUZ_DISPLAYTEST();
{ int const availableSpace = (FUZ_rand(&randState) % blockSize) + 5;