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author | Yann Collet <Cyan4973@users.noreply.github.com> | 2018-04-24 17:49:41 (GMT) |
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committer | GitHub <noreply@github.com> | 2018-04-24 17:49:41 (GMT) |
commit | c92df763614fe00739842e6180d09e1b03ac18c2 (patch) | |
tree | fdc4ec83381303fc991785be611b6620c144e661 /lib | |
parent | 746d5f7e4b084da172a61098c576cfa016e67274 (diff) | |
parent | 5ed1463bf4668a0e668679ae1e458aa73aa9a6ec (diff) | |
download | lz4-c92df763614fe00739842e6180d09e1b03ac18c2.zip lz4-c92df763614fe00739842e6180d09e1b03ac18c2.tar.gz lz4-c92df763614fe00739842e6180d09e1b03ac18c2.tar.bz2 |
Merge pull request #488 from felixhandte/hc-dict-ctx
Use Dictionary In-Place in HC Mode
Diffstat (limited to 'lib')
-rw-r--r-- | lib/lz4frame.c | 12 | ||||
-rw-r--r-- | lib/lz4hc.c | 223 | ||||
-rw-r--r-- | lib/lz4hc.h | 83 |
3 files changed, 266 insertions, 52 deletions
diff --git a/lib/lz4frame.c b/lib/lz4frame.c index 507e4fe..844c8d1 100644 --- a/lib/lz4frame.c +++ b/lib/lz4frame.c @@ -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) diff --git a/lib/lz4hc.c b/lib/lz4hc.c index 111a09b..4126ef8 100644 --- a/lib/lz4hc.c +++ b/lib/lz4hc.c @@ -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) diff --git a/lib/lz4hc.h b/lib/lz4hc.h index 7a25bee..28e2528 100644 --- a/lib/lz4hc.h +++ b/lib/lz4hc.h @@ -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 */ |