diff options
Diffstat (limited to 'contrib/zstd/zstd_compress_internal.h')
| -rw-r--r-- | contrib/zstd/zstd_compress_internal.h | 749 |
1 files changed, 551 insertions, 198 deletions
diff --git a/contrib/zstd/zstd_compress_internal.h b/contrib/zstd/zstd_compress_internal.h index c500687ce..e53b3a53f 100644 --- a/contrib/zstd/zstd_compress_internal.h +++ b/contrib/zstd/zstd_compress_internal.h @@ -1,5 +1,5 @@ /* - * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc. + * Copyright (c) Meta Platforms, Inc. and affiliates. * All rights reserved. * * This source code is licensed under both the BSD-style license (found in the @@ -23,12 +23,12 @@ #ifdef ZSTD_MULTITHREAD # include "zstdmt_compress.h" #endif +#include "bits.h" /* ZSTD_highbit32, ZSTD_NbCommonBytes */ #if defined (__cplusplus) extern "C" { #endif - /*-************************************* * Constants ***************************************/ @@ -64,7 +64,7 @@ typedef struct { } ZSTD_localDict; typedef struct { - U32 CTable[HUF_CTABLE_SIZE_U32(255)]; + HUF_CElt CTable[HUF_CTABLE_SIZE_ST(255)]; HUF_repeat repeatMode; } ZSTD_hufCTables_t; @@ -82,12 +82,83 @@ typedef struct { ZSTD_fseCTables_t fse; } ZSTD_entropyCTables_t; +/*********************************************** +* Entropy buffer statistics structs and funcs * +***********************************************/ +/** ZSTD_hufCTablesMetadata_t : + * Stores Literals Block Type for a super-block in hType, and + * huffman tree description in hufDesBuffer. + * hufDesSize refers to the size of huffman tree description in bytes. + * This metadata is populated in ZSTD_buildBlockEntropyStats_literals() */ typedef struct { - U32 off; - U32 len; + symbolEncodingType_e hType; + BYTE hufDesBuffer[ZSTD_MAX_HUF_HEADER_SIZE]; + size_t hufDesSize; +} ZSTD_hufCTablesMetadata_t; + +/** ZSTD_fseCTablesMetadata_t : + * Stores symbol compression modes for a super-block in {ll, ol, ml}Type, and + * fse tables in fseTablesBuffer. + * fseTablesSize refers to the size of fse tables in bytes. + * This metadata is populated in ZSTD_buildBlockEntropyStats_sequences() */ +typedef struct { + symbolEncodingType_e llType; + symbolEncodingType_e ofType; + symbolEncodingType_e mlType; + BYTE fseTablesBuffer[ZSTD_MAX_FSE_HEADERS_SIZE]; + size_t fseTablesSize; + size_t lastCountSize; /* This is to account for bug in 1.3.4. More detail in ZSTD_entropyCompressSeqStore_internal() */ +} ZSTD_fseCTablesMetadata_t; + +typedef struct { + ZSTD_hufCTablesMetadata_t hufMetadata; + ZSTD_fseCTablesMetadata_t fseMetadata; +} ZSTD_entropyCTablesMetadata_t; + +/** ZSTD_buildBlockEntropyStats() : + * Builds entropy for the block. + * @return : 0 on success or error code */ +size_t ZSTD_buildBlockEntropyStats( + const seqStore_t* seqStorePtr, + const ZSTD_entropyCTables_t* prevEntropy, + ZSTD_entropyCTables_t* nextEntropy, + const ZSTD_CCtx_params* cctxParams, + ZSTD_entropyCTablesMetadata_t* entropyMetadata, + void* workspace, size_t wkspSize); + +/********************************* +* Compression internals structs * +*********************************/ + +typedef struct { + U32 off; /* Offset sumtype code for the match, using ZSTD_storeSeq() format */ + U32 len; /* Raw length of match */ } ZSTD_match_t; typedef struct { + U32 offset; /* Offset of sequence */ + U32 litLength; /* Length of literals prior to match */ + U32 matchLength; /* Raw length of match */ +} rawSeq; + +typedef struct { + rawSeq* seq; /* The start of the sequences */ + size_t pos; /* The index in seq where reading stopped. pos <= size. */ + size_t posInSequence; /* The position within the sequence at seq[pos] where reading + stopped. posInSequence <= seq[pos].litLength + seq[pos].matchLength */ + size_t size; /* The number of sequences. <= capacity. */ + size_t capacity; /* The capacity starting from `seq` pointer */ +} rawSeqStore_t; + +typedef struct { + U32 idx; /* Index in array of ZSTD_Sequence */ + U32 posInSequence; /* Position within sequence at idx */ + size_t posInSrc; /* Number of bytes given by sequences provided so far */ +} ZSTD_sequencePosition; + +UNUSED_ATTR static const rawSeqStore_t kNullRawSeqStore = {NULL, 0, 0, 0, 0}; + +typedef struct { int price; U32 off; U32 mlen; @@ -116,7 +187,7 @@ typedef struct { U32 offCodeSumBasePrice; /* to compare to log2(offreq) */ ZSTD_OptPrice_e priceType; /* prices can be determined dynamically, or follow a pre-defined cost structure */ const ZSTD_entropyCTables_t* symbolCosts; /* pre-calculated dictionary statistics */ - ZSTD_literalCompressionMode_e literalCompressionMode; + ZSTD_paramSwitch_e literalCompressionMode; } optState_t; typedef struct { @@ -125,14 +196,23 @@ typedef struct { } ZSTD_compressedBlockState_t; typedef struct { - BYTE const* nextSrc; /* next block here to continue on current prefix */ - BYTE const* base; /* All regular indexes relative to this position */ - BYTE const* dictBase; /* extDict indexes relative to this position */ - U32 dictLimit; /* below that point, need extDict */ - U32 lowLimit; /* below that point, no more valid data */ + BYTE const* nextSrc; /* next block here to continue on current prefix */ + BYTE const* base; /* All regular indexes relative to this position */ + BYTE const* dictBase; /* extDict indexes relative to this position */ + U32 dictLimit; /* below that point, need extDict */ + U32 lowLimit; /* below that point, no more valid data */ + U32 nbOverflowCorrections; /* Number of times overflow correction has run since + * ZSTD_window_init(). Useful for debugging coredumps + * and for ZSTD_WINDOW_OVERFLOW_CORRECT_FREQUENTLY. + */ } ZSTD_window_t; +#define ZSTD_WINDOW_START_INDEX 2 + typedef struct ZSTD_matchState_t ZSTD_matchState_t; + +#define ZSTD_ROW_HASH_CACHE_SIZE 8 /* Size of prefetching hash cache for row-based matchfinder */ + struct ZSTD_matchState_t { ZSTD_window_t window; /* State for window round buffer management */ U32 loadedDictEnd; /* index of end of dictionary, within context's referential. @@ -144,12 +224,29 @@ struct ZSTD_matchState_t { */ U32 nextToUpdate; /* index from which to continue table update */ U32 hashLog3; /* dispatch table for matches of len==3 : larger == faster, more memory */ + + U32 rowHashLog; /* For row-based matchfinder: Hashlog based on nb of rows in the hashTable.*/ + U16* tagTable; /* For row-based matchFinder: A row-based table containing the hashes and head index. */ + U32 hashCache[ZSTD_ROW_HASH_CACHE_SIZE]; /* For row-based matchFinder: a cache of hashes to improve speed */ + U32* hashTable; U32* hashTable3; U32* chainTable; + + U32 forceNonContiguous; /* Non-zero if we should force non-contiguous load for the next window update. */ + + int dedicatedDictSearch; /* Indicates whether this matchState is using the + * dedicated dictionary search structure. + */ optState_t opt; /* optimal parser state */ const ZSTD_matchState_t* dictMatchState; ZSTD_compressionParameters cParams; + const rawSeqStore_t* ldmSeqStore; + + /* Controls prefetching in some dictMatchState matchfinders. + * This behavior is controlled from the cctx ms. + * This parameter has no effect in the cdict ms. */ + int prefetchCDictTables; }; typedef struct { @@ -164,16 +261,25 @@ typedef struct { } ldmEntry_t; typedef struct { + BYTE const* split; + U32 hash; + U32 checksum; + ldmEntry_t* bucket; +} ldmMatchCandidate_t; + +#define LDM_BATCH_SIZE 64 + +typedef struct { ZSTD_window_t window; /* State for the window round buffer management */ ldmEntry_t* hashTable; U32 loadedDictEnd; BYTE* bucketOffsets; /* Next position in bucket to insert entry */ - U64 hashPower; /* Used to compute the rolling hash. - * Depends on ldmParams.minMatchLength */ + size_t splitIndices[LDM_BATCH_SIZE]; + ldmMatchCandidate_t matchCandidates[LDM_BATCH_SIZE]; } ldmState_t; typedef struct { - U32 enableLdm; /* 1 if enable long distance matching */ + ZSTD_paramSwitch_e enableLdm; /* ZSTD_ps_enable to enable LDM. ZSTD_ps_auto by default */ U32 hashLog; /* Log size of hashTable */ U32 bucketSizeLog; /* Log bucket size for collision resolution, at most 8 */ U32 minMatchLength; /* Minimum match length */ @@ -182,19 +288,6 @@ typedef struct { } ldmParams_t; typedef struct { - U32 offset; - U32 litLength; - U32 matchLength; -} rawSeq; - -typedef struct { - rawSeq* seq; /* The start of the sequences */ - size_t pos; /* The position where reading stopped. <= size. */ - size_t size; /* The number of sequences. <= capacity. */ - size_t capacity; /* The capacity starting from `seq` pointer */ -} rawSeqStore_t; - -typedef struct { int collectSequences; ZSTD_Sequence* seqStart; size_t seqIndex; @@ -217,7 +310,7 @@ struct ZSTD_CCtx_params_s { * There is no guarantee that hint is close to actual source size */ ZSTD_dictAttachPref_e attachDictPref; - ZSTD_literalCompressionMode_e literalCompressionMode; + ZSTD_paramSwitch_e literalCompressionMode; /* Multithreading: used to pass parameters to mtctx */ int nbWorkers; @@ -228,17 +321,94 @@ struct ZSTD_CCtx_params_s { /* Long distance matching parameters */ ldmParams_t ldmParams; + /* Dedicated dict search algorithm trigger */ + int enableDedicatedDictSearch; + + /* Input/output buffer modes */ + ZSTD_bufferMode_e inBufferMode; + ZSTD_bufferMode_e outBufferMode; + + /* Sequence compression API */ + ZSTD_sequenceFormat_e blockDelimiters; + int validateSequences; + + /* Block splitting */ + ZSTD_paramSwitch_e useBlockSplitter; + + /* Param for deciding whether to use row-based matchfinder */ + ZSTD_paramSwitch_e useRowMatchFinder; + + /* Always load a dictionary in ext-dict mode (not prefix mode)? */ + int deterministicRefPrefix; + /* Internal use, for createCCtxParams() and freeCCtxParams() only */ ZSTD_customMem customMem; + + /* Controls prefetching in some dictMatchState matchfinders */ + ZSTD_paramSwitch_e prefetchCDictTables; + + /* Controls whether zstd will fall back to an internal matchfinder + * if the external matchfinder returns an error code. */ + int enableMatchFinderFallback; + + /* Indicates whether an external matchfinder has been referenced. + * Users can't set this externally. + * It is set internally in ZSTD_registerSequenceProducer(). */ + int useSequenceProducer; + + /* Adjust the max block size*/ + size_t maxBlockSize; + + /* Controls repcode search in external sequence parsing */ + ZSTD_paramSwitch_e searchForExternalRepcodes; }; /* typedef'd to ZSTD_CCtx_params within "zstd.h" */ +#define COMPRESS_SEQUENCES_WORKSPACE_SIZE (sizeof(unsigned) * (MaxSeq + 2)) +#define ENTROPY_WORKSPACE_SIZE (HUF_WORKSPACE_SIZE + COMPRESS_SEQUENCES_WORKSPACE_SIZE) + +/** + * Indicates whether this compression proceeds directly from user-provided + * source buffer to user-provided destination buffer (ZSTDb_not_buffered), or + * whether the context needs to buffer the input/output (ZSTDb_buffered). + */ +typedef enum { + ZSTDb_not_buffered, + ZSTDb_buffered +} ZSTD_buffered_policy_e; + +/** + * Struct that contains all elements of block splitter that should be allocated + * in a wksp. + */ +#define ZSTD_MAX_NB_BLOCK_SPLITS 196 +typedef struct { + seqStore_t fullSeqStoreChunk; + seqStore_t firstHalfSeqStore; + seqStore_t secondHalfSeqStore; + seqStore_t currSeqStore; + seqStore_t nextSeqStore; + + U32 partitions[ZSTD_MAX_NB_BLOCK_SPLITS]; + ZSTD_entropyCTablesMetadata_t entropyMetadata; +} ZSTD_blockSplitCtx; + +/* Context for block-level external matchfinder API */ +typedef struct { + void* mState; + ZSTD_sequenceProducer_F* mFinder; + ZSTD_Sequence* seqBuffer; + size_t seqBufferCapacity; +} ZSTD_externalMatchCtx; + struct ZSTD_CCtx_s { ZSTD_compressionStage_e stage; int cParamsChanged; /* == 1 if cParams(except wlog) or compression level are changed in requestedParams. Triggers transmission of new params to ZSTDMT (if available) then reset to 0. */ int bmi2; /* == 1 if the CPU supports BMI2 and 0 otherwise. CPU support is determined dynamically once per context lifetime. */ ZSTD_CCtx_params requestedParams; ZSTD_CCtx_params appliedParams; + ZSTD_CCtx_params simpleApiParams; /* Param storage used by the simple API - not sticky. Must only be used in top-level simple API functions for storage. */ U32 dictID; + size_t dictContentSize; ZSTD_cwksp workspace; /* manages buffer for dynamic allocations */ size_t blockSize; @@ -247,6 +417,7 @@ struct ZSTD_CCtx_s { unsigned long long producedCSize; XXH64_state_t xxhState; ZSTD_customMem customMem; + ZSTD_threadPool* pool; size_t staticSize; SeqCollector seqCollector; int isFirstBlock; @@ -258,7 +429,10 @@ struct ZSTD_CCtx_s { size_t maxNbLdmSequences; rawSeqStore_t externSeqStore; /* Mutable reference to external sequences */ ZSTD_blockState_t blockState; - U32* entropyWorkspace; /* entropy workspace of HUF_WORKSPACE_SIZE bytes */ + U32* entropyWorkspace; /* entropy workspace of ENTROPY_WORKSPACE_SIZE bytes */ + + /* Whether we are streaming or not */ + ZSTD_buffered_policy_e bufferedPolicy; /* streaming */ char* inBuff; @@ -273,6 +447,11 @@ struct ZSTD_CCtx_s { ZSTD_cStreamStage streamStage; U32 frameEnded; + /* Stable in/out buffer verification */ + ZSTD_inBuffer expectedInBuffer; + size_t stableIn_notConsumed; /* nb bytes within stable input buffer that are said to be consumed but are not */ + size_t expectedOutBufferSize; + /* Dictionary */ ZSTD_localDict localDict; const ZSTD_CDict* cdict; @@ -282,17 +461,53 @@ struct ZSTD_CCtx_s { #ifdef ZSTD_MULTITHREAD ZSTDMT_CCtx* mtctx; #endif -}; -typedef enum { ZSTD_dtlm_fast, ZSTD_dtlm_full } ZSTD_dictTableLoadMethod_e; + /* Tracing */ +#if ZSTD_TRACE + ZSTD_TraceCtx traceCtx; +#endif -typedef enum { ZSTD_noDict = 0, ZSTD_extDict = 1, ZSTD_dictMatchState = 2 } ZSTD_dictMode_e; + /* Workspace for block splitter */ + ZSTD_blockSplitCtx blockSplitCtx; + + /* Workspace for external matchfinder */ + ZSTD_externalMatchCtx externalMatchCtx; +}; +typedef enum { ZSTD_dtlm_fast, ZSTD_dtlm_full } ZSTD_dictTableLoadMethod_e; +typedef enum { ZSTD_tfp_forCCtx, ZSTD_tfp_forCDict } ZSTD_tableFillPurpose_e; + +typedef enum { + ZSTD_noDict = 0, + ZSTD_extDict = 1, + ZSTD_dictMatchState = 2, + ZSTD_dedicatedDictSearch = 3 +} ZSTD_dictMode_e; + +typedef enum { + ZSTD_cpm_noAttachDict = 0, /* Compression with ZSTD_noDict or ZSTD_extDict. + * In this mode we use both the srcSize and the dictSize + * when selecting and adjusting parameters. + */ + ZSTD_cpm_attachDict = 1, /* Compression with ZSTD_dictMatchState or ZSTD_dedicatedDictSearch. + * In this mode we only take the srcSize into account when selecting + * and adjusting parameters. + */ + ZSTD_cpm_createCDict = 2, /* Creating a CDict. + * In this mode we take both the source size and the dictionary size + * into account when selecting and adjusting the parameters. + */ + ZSTD_cpm_unknown = 3 /* ZSTD_getCParams, ZSTD_getParams, ZSTD_adjustParams. + * We don't know what these parameters are for. We default to the legacy + * behavior of taking both the source size and the dict size into account + * when selecting and adjusting parameters. + */ +} ZSTD_cParamMode_e; typedef size_t (*ZSTD_blockCompressor) ( ZSTD_matchState_t* bs, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], void const* src, size_t srcSize); -ZSTD_blockCompressor ZSTD_selectBlockCompressor(ZSTD_strategy strat, ZSTD_dictMode_e dictMode); +ZSTD_blockCompressor ZSTD_selectBlockCompressor(ZSTD_strategy strat, ZSTD_paramSwitch_e rowMatchfinderMode, ZSTD_dictMode_e dictMode); MEM_STATIC U32 ZSTD_LLcode(U32 litLength) @@ -326,31 +541,6 @@ MEM_STATIC U32 ZSTD_MLcode(U32 mlBase) return (mlBase > 127) ? ZSTD_highbit32(mlBase) + ML_deltaCode : ML_Code[mlBase]; } -typedef struct repcodes_s { - U32 rep[3]; -} repcodes_t; - -MEM_STATIC repcodes_t ZSTD_updateRep(U32 const rep[3], U32 const offset, U32 const ll0) -{ - repcodes_t newReps; - if (offset >= ZSTD_REP_NUM) { /* full offset */ - newReps.rep[2] = rep[1]; - newReps.rep[1] = rep[0]; - newReps.rep[0] = offset - ZSTD_REP_MOVE; - } else { /* repcode */ - U32 const repCode = offset + ll0; - if (repCode > 0) { /* note : if repCode==0, no change */ - U32 const currentOffset = (repCode==ZSTD_REP_NUM) ? (rep[0] - 1) : rep[repCode]; - newReps.rep[2] = (repCode >= 2) ? rep[1] : rep[2]; - newReps.rep[1] = rep[0]; - newReps.rep[0] = currentOffset; - } else { /* repCode == 0 */ - memcpy(&newReps, rep, sizeof(newReps)); - } - } - return newReps; -} - /* ZSTD_cParam_withinBounds: * @return 1 if value is within cParam bounds, * 0 otherwise */ @@ -366,17 +556,20 @@ MEM_STATIC int ZSTD_cParam_withinBounds(ZSTD_cParameter cParam, int value) /* ZSTD_noCompressBlock() : * Writes uncompressed block to dst buffer from given src. * Returns the size of the block */ -MEM_STATIC size_t ZSTD_noCompressBlock (void* dst, size_t dstCapacity, const void* src, size_t srcSize, U32 lastBlock) +MEM_STATIC size_t +ZSTD_noCompressBlock(void* dst, size_t dstCapacity, const void* src, size_t srcSize, U32 lastBlock) { U32 const cBlockHeader24 = lastBlock + (((U32)bt_raw)<<1) + (U32)(srcSize << 3); + DEBUGLOG(5, "ZSTD_noCompressBlock (srcSize=%zu, dstCapacity=%zu)", srcSize, dstCapacity); RETURN_ERROR_IF(srcSize + ZSTD_blockHeaderSize > dstCapacity, dstSize_tooSmall, "dst buf too small for uncompressed block"); MEM_writeLE24(dst, cBlockHeader24); - memcpy((BYTE*)dst + ZSTD_blockHeaderSize, src, srcSize); + ZSTD_memcpy((BYTE*)dst + ZSTD_blockHeaderSize, src, srcSize); return ZSTD_blockHeaderSize + srcSize; } -MEM_STATIC size_t ZSTD_rleCompressBlock (void* dst, size_t dstCapacity, BYTE src, size_t srcSize, U32 lastBlock) +MEM_STATIC size_t +ZSTD_rleCompressBlock(void* dst, size_t dstCapacity, BYTE src, size_t srcSize, U32 lastBlock) { BYTE* const op = (BYTE*)dst; U32 const cBlockHeader = lastBlock + (((U32)bt_rle)<<1) + (U32)(srcSize << 3); @@ -395,21 +588,21 @@ MEM_STATIC size_t ZSTD_minGain(size_t srcSize, ZSTD_strategy strat) { U32 const minlog = (strat>=ZSTD_btultra) ? (U32)(strat) - 1 : 6; ZSTD_STATIC_ASSERT(ZSTD_btultra == 8); - assert(ZSTD_cParam_withinBounds(ZSTD_c_strategy, strat)); + assert(ZSTD_cParam_withinBounds(ZSTD_c_strategy, (int)strat)); return (srcSize >> minlog) + 2; } -MEM_STATIC int ZSTD_disableLiteralsCompression(const ZSTD_CCtx_params* cctxParams) +MEM_STATIC int ZSTD_literalsCompressionIsDisabled(const ZSTD_CCtx_params* cctxParams) { switch (cctxParams->literalCompressionMode) { - case ZSTD_lcm_huffman: + case ZSTD_ps_enable: return 0; - case ZSTD_lcm_uncompressed: + case ZSTD_ps_disable: return 1; default: assert(0 /* impossible: pre-validated */); - /* fall-through */ - case ZSTD_lcm_auto: + ZSTD_FALLTHROUGH; + case ZSTD_ps_auto: return (cctxParams->cParams.strategy == ZSTD_fast) && (cctxParams->cParams.targetLength > 0); } } @@ -419,7 +612,9 @@ MEM_STATIC int ZSTD_disableLiteralsCompression(const ZSTD_CCtx_params* cctxParam * Only called when the sequence ends past ilimit_w, so it only needs to be optimized for single * large copies. */ -static void ZSTD_safecopyLiterals(BYTE* op, BYTE const* ip, BYTE const* const iend, BYTE const* ilimit_w) { +static void +ZSTD_safecopyLiterals(BYTE* op, BYTE const* ip, BYTE const* const iend, BYTE const* ilimit_w) +{ assert(iend > ilimit_w); if (ip <= ilimit_w) { ZSTD_wildcopy(op, ip, ilimit_w - ip, ZSTD_no_overlap); @@ -429,14 +624,28 @@ static void ZSTD_safecopyLiterals(BYTE* op, BYTE const* ip, BYTE const* const ie while (ip < iend) *op++ = *ip++; } + +#define REPCODE1_TO_OFFBASE REPCODE_TO_OFFBASE(1) +#define REPCODE2_TO_OFFBASE REPCODE_TO_OFFBASE(2) +#define REPCODE3_TO_OFFBASE REPCODE_TO_OFFBASE(3) +#define REPCODE_TO_OFFBASE(r) (assert((r)>=1), assert((r)<=ZSTD_REP_NUM), (r)) /* accepts IDs 1,2,3 */ +#define OFFSET_TO_OFFBASE(o) (assert((o)>0), o + ZSTD_REP_NUM) +#define OFFBASE_IS_OFFSET(o) ((o) > ZSTD_REP_NUM) +#define OFFBASE_IS_REPCODE(o) ( 1 <= (o) && (o) <= ZSTD_REP_NUM) +#define OFFBASE_TO_OFFSET(o) (assert(OFFBASE_IS_OFFSET(o)), (o) - ZSTD_REP_NUM) +#define OFFBASE_TO_REPCODE(o) (assert(OFFBASE_IS_REPCODE(o)), (o)) /* returns ID 1,2,3 */ + /*! ZSTD_storeSeq() : - * Store a sequence (litlen, litPtr, offCode and mlBase) into seqStore_t. - * `offCode` : distance to match + ZSTD_REP_MOVE (values <= ZSTD_REP_MOVE are repCodes). - * `mlBase` : matchLength - MINMATCH - * Allowed to overread literals up to litLimit. + * Store a sequence (litlen, litPtr, offBase and matchLength) into seqStore_t. + * @offBase : Users should employ macros REPCODE_TO_OFFBASE() and OFFSET_TO_OFFBASE(). + * @matchLength : must be >= MINMATCH + * Allowed to over-read literals up to litLimit. */ -HINT_INLINE UNUSED_ATTR -void ZSTD_storeSeq(seqStore_t* seqStorePtr, size_t litLength, const BYTE* literals, const BYTE* litLimit, U32 offCode, size_t mlBase) +HINT_INLINE UNUSED_ATTR void +ZSTD_storeSeq(seqStore_t* seqStorePtr, + size_t litLength, const BYTE* literals, const BYTE* litLimit, + U32 offBase, + size_t matchLength) { BYTE const* const litLimit_w = litLimit - WILDCOPY_OVERLENGTH; BYTE const* const litEnd = literals + litLength; @@ -444,8 +653,8 @@ void ZSTD_storeSeq(seqStore_t* seqStorePtr, size_t litLength, const BYTE* litera static const BYTE* g_start = NULL; if (g_start==NULL) g_start = (const BYTE*)literals; /* note : index only works for compression within a single segment */ { U32 const pos = (U32)((const BYTE*)literals - g_start); - DEBUGLOG(6, "Cpos%7u :%3u literals, match%4u bytes at offCode%7u", - pos, (U32)litLength, (U32)mlBase+MINMATCH, (U32)offCode); + DEBUGLOG(6, "Cpos%7u :%3u literals, match%4u bytes at offBase%7u", + pos, (U32)litLength, (U32)matchLength, (U32)offBase); } #endif assert((size_t)(seqStorePtr->sequences - seqStorePtr->sequencesStart) < seqStorePtr->maxNbSeq); @@ -455,9 +664,9 @@ void ZSTD_storeSeq(seqStore_t* seqStorePtr, size_t litLength, const BYTE* litera assert(literals + litLength <= litLimit); if (litEnd <= litLimit_w) { /* Common case we can use wildcopy. - * First copy 16 bytes, because literals are likely short. - */ - assert(WILDCOPY_OVERLENGTH >= 16); + * First copy 16 bytes, because literals are likely short. + */ + ZSTD_STATIC_ASSERT(WILDCOPY_OVERLENGTH >= 16); ZSTD_copy16(seqStorePtr->lit, literals); if (litLength > 16) { ZSTD_wildcopy(seqStorePtr->lit+16, literals+16, (ptrdiff_t)litLength-16, ZSTD_no_overlap); @@ -469,95 +678,70 @@ void ZSTD_storeSeq(seqStore_t* seqStorePtr, size_t litLength, const BYTE* litera /* literal Length */ if (litLength>0xFFFF) { - assert(seqStorePtr->longLengthID == 0); /* there can only be a single long length */ - seqStorePtr->longLengthID = 1; + assert(seqStorePtr->longLengthType == ZSTD_llt_none); /* there can only be a single long length */ + seqStorePtr->longLengthType = ZSTD_llt_literalLength; seqStorePtr->longLengthPos = (U32)(seqStorePtr->sequences - seqStorePtr->sequencesStart); } seqStorePtr->sequences[0].litLength = (U16)litLength; /* match offset */ - seqStorePtr->sequences[0].offset = offCode + 1; + seqStorePtr->sequences[0].offBase = offBase; /* match Length */ - if (mlBase>0xFFFF) { - assert(seqStorePtr->longLengthID == 0); /* there can only be a single long length */ - seqStorePtr->longLengthID = 2; - seqStorePtr->longLengthPos = (U32)(seqStorePtr->sequences - seqStorePtr->sequencesStart); + assert(matchLength >= MINMATCH); + { size_t const mlBase = matchLength - MINMATCH; + if (mlBase>0xFFFF) { + assert(seqStorePtr->longLengthType == ZSTD_llt_none); /* there can only be a single long length */ + seqStorePtr->longLengthType = ZSTD_llt_matchLength; + seqStorePtr->longLengthPos = (U32)(seqStorePtr->sequences - seqStorePtr->sequencesStart); + } + seqStorePtr->sequences[0].mlBase = (U16)mlBase; } - seqStorePtr->sequences[0].matchLength = (U16)mlBase; seqStorePtr->sequences++; } - -/*-************************************* -* Match length counter -***************************************/ -static unsigned ZSTD_NbCommonBytes (size_t val) +/* ZSTD_updateRep() : + * updates in-place @rep (array of repeat offsets) + * @offBase : sum-type, using numeric representation of ZSTD_storeSeq() + */ +MEM_STATIC void +ZSTD_updateRep(U32 rep[ZSTD_REP_NUM], U32 const offBase, U32 const ll0) { - if (MEM_isLittleEndian()) { - if (MEM_64bits()) { -# if defined(_MSC_VER) && defined(_WIN64) - unsigned long r = 0; - return _BitScanForward64( &r, (U64)val ) ? (unsigned)(r >> 3) : 0; -# elif defined(__GNUC__) && (__GNUC__ >= 4) - return (__builtin_ctzll((U64)val) >> 3); -# else - static const int DeBruijnBytePos[64] = { 0, 0, 0, 0, 0, 1, 1, 2, - 0, 3, 1, 3, 1, 4, 2, 7, - 0, 2, 3, 6, 1, 5, 3, 5, - 1, 3, 4, 4, 2, 5, 6, 7, - 7, 0, 1, 2, 3, 3, 4, 6, - 2, 6, 5, 5, 3, 4, 5, 6, - 7, 1, 2, 4, 6, 4, 4, 5, - 7, 2, 6, 5, 7, 6, 7, 7 }; - return DeBruijnBytePos[((U64)((val & -(long long)val) * 0x0218A392CDABBD3FULL)) >> 58]; -# endif - } else { /* 32 bits */ -# if defined(_MSC_VER) - unsigned long r=0; - return _BitScanForward( &r, (U32)val ) ? (unsigned)(r >> 3) : 0; -# elif defined(__GNUC__) && (__GNUC__ >= 3) - return (__builtin_ctz((U32)val) >> 3); -# else - static const int DeBruijnBytePos[32] = { 0, 0, 3, 0, 3, 1, 3, 0, - 3, 2, 2, 1, 3, 2, 0, 1, - 3, 3, 1, 2, 2, 2, 2, 0, - 3, 1, 2, 0, 1, 0, 1, 1 }; - return DeBruijnBytePos[((U32)((val & -(S32)val) * 0x077CB531U)) >> 27]; -# endif + if (OFFBASE_IS_OFFSET(offBase)) { /* full offset */ + rep[2] = rep[1]; + rep[1] = rep[0]; + rep[0] = OFFBASE_TO_OFFSET(offBase); + } else { /* repcode */ + U32 const repCode = OFFBASE_TO_REPCODE(offBase) - 1 + ll0; + if (repCode > 0) { /* note : if repCode==0, no change */ + U32 const currentOffset = (repCode==ZSTD_REP_NUM) ? (rep[0] - 1) : rep[repCode]; + rep[2] = (repCode >= 2) ? rep[1] : rep[2]; + rep[1] = rep[0]; + rep[0] = currentOffset; + } else { /* repCode == 0 */ + /* nothing to do */ } - } else { /* Big Endian CPU */ - if (MEM_64bits()) { -# if defined(_MSC_VER) && defined(_WIN64) - unsigned long r = 0; - return _BitScanReverse64( &r, val ) ? (unsigned)(r >> 3) : 0; -# elif defined(__GNUC__) && (__GNUC__ >= 4) - return (__builtin_clzll(val) >> 3); -# else - unsigned r; - const unsigned n32 = sizeof(size_t)*4; /* calculate this way due to compiler complaining in 32-bits mode */ - if (!(val>>n32)) { r=4; } else { r=0; val>>=n32; } - if (!(val>>16)) { r+=2; val>>=8; } else { val>>=24; } - r += (!val); - return r; -# endif - } else { /* 32 bits */ -# if defined(_MSC_VER) - unsigned long r = 0; - return _BitScanReverse( &r, (unsigned long)val ) ? (unsigned)(r >> 3) : 0; -# elif defined(__GNUC__) && (__GNUC__ >= 3) - return (__builtin_clz((U32)val) >> 3); -# else - unsigned r; - if (!(val>>16)) { r=2; val>>=8; } else { r=0; val>>=24; } - r += (!val); - return r; -# endif - } } + } +} + +typedef struct repcodes_s { + U32 rep[3]; +} repcodes_t; + +MEM_STATIC repcodes_t +ZSTD_newRep(U32 const rep[ZSTD_REP_NUM], U32 const offBase, U32 const ll0) +{ + repcodes_t newReps; + ZSTD_memcpy(&newReps, rep, sizeof(newReps)); + ZSTD_updateRep(newReps.rep, offBase, ll0); + return newReps; } +/*-************************************* +* Match length counter +***************************************/ MEM_STATIC size_t ZSTD_count(const BYTE* pIn, const BYTE* pMatch, const BYTE* const pInLimit) { const BYTE* const pStart = pIn; @@ -603,31 +787,36 @@ ZSTD_count_2segments(const BYTE* ip, const BYTE* match, * Hashes ***************************************/ static const U32 prime3bytes = 506832829U; -static U32 ZSTD_hash3(U32 u, U32 h) { return ((u << (32-24)) * prime3bytes) >> (32-h) ; } +static U32 ZSTD_hash3(U32 u, U32 h) { assert(h <= 32); return ((u << (32-24)) * prime3bytes) >> (32-h) ; } MEM_STATIC size_t ZSTD_hash3Ptr(const void* ptr, U32 h) { return ZSTD_hash3(MEM_readLE32(ptr), h); } /* only in zstd_opt.h */ static const U32 prime4bytes = 2654435761U; -static U32 ZSTD_hash4(U32 u, U32 h) { return (u * prime4bytes) >> (32-h) ; } -static size_t ZSTD_hash4Ptr(const void* ptr, U32 h) { return ZSTD_hash4(MEM_read32(ptr), h); } +static U32 ZSTD_hash4(U32 u, U32 h) { assert(h <= 32); return (u * prime4bytes) >> (32-h) ; } +static size_t ZSTD_hash4Ptr(const void* ptr, U32 h) { return ZSTD_hash4(MEM_readLE32(ptr), h); } static const U64 prime5bytes = 889523592379ULL; -static size_t ZSTD_hash5(U64 u, U32 h) { return (size_t)(((u << (64-40)) * prime5bytes) >> (64-h)) ; } +static size_t ZSTD_hash5(U64 u, U32 h) { assert(h <= 64); return (size_t)(((u << (64-40)) * prime5bytes) >> (64-h)) ; } static size_t ZSTD_hash5Ptr(const void* p, U32 h) { return ZSTD_hash5(MEM_readLE64(p), h); } static const U64 prime6bytes = 227718039650203ULL; -static size_t ZSTD_hash6(U64 u, U32 h) { return (size_t)(((u << (64-48)) * prime6bytes) >> (64-h)) ; } +static size_t ZSTD_hash6(U64 u, U32 h) { assert(h <= 64); return (size_t)(((u << (64-48)) * prime6bytes) >> (64-h)) ; } static size_t ZSTD_hash6Ptr(const void* p, U32 h) { return ZSTD_hash6(MEM_readLE64(p), h); } static const U64 prime7bytes = 58295818150454627ULL; -static size_t ZSTD_hash7(U64 u, U32 h) { return (size_t)(((u << (64-56)) * prime7bytes) >> (64-h)) ; } +static size_t ZSTD_hash7(U64 u, U32 h) { assert(h <= 64); return (size_t)(((u << (64-56)) * prime7bytes) >> (64-h)) ; } static size_t ZSTD_hash7Ptr(const void* p, U32 h) { return ZSTD_hash7(MEM_readLE64(p), h); } static const U64 prime8bytes = 0xCF1BBCDCB7A56463ULL; -static size_t ZSTD_hash8(U64 u, U32 h) { return (size_t)(((u) * prime8bytes) >> (64-h)) ; } +static size_t ZSTD_hash8(U64 u, U32 h) { assert(h <= 64); return (size_t)(((u) * prime8bytes) >> (64-h)) ; } static size_t ZSTD_hash8Ptr(const void* p, U32 h) { return ZSTD_hash8(MEM_readLE64(p), h); } -MEM_STATIC size_t ZSTD_hashPtr(const void* p, U32 hBits, U32 mls) +MEM_STATIC FORCE_INLINE_ATTR +size_t ZSTD_hashPtr(const void* p, U32 hBits, U32 mls) { + /* Although some of these hashes do support hBits up to 64, some do not. + * To be on the safe side, always avoid hBits > 32. */ + assert(hBits <= 32); + switch(mls) { default: @@ -723,6 +912,13 @@ MEM_STATIC void ZSTD_window_clear(ZSTD_window_t* window) window->dictLimit = end; } +MEM_STATIC U32 ZSTD_window_isEmpty(ZSTD_window_t const window) +{ + return window.dictLimit == ZSTD_WINDOW_START_INDEX && + window.lowLimit == ZSTD_WINDOW_START_INDEX && + (window.nextSrc - window.base) == ZSTD_WINDOW_START_INDEX; +} + /** * ZSTD_window_hasExtDict(): * Returns non-zero if the window has a non-empty extDict. @@ -742,20 +938,76 @@ MEM_STATIC ZSTD_dictMode_e ZSTD_matchState_dictMode(const ZSTD_matchState_t *ms) return ZSTD_window_hasExtDict(ms->window) ? ZSTD_extDict : ms->dictMatchState != NULL ? - ZSTD_dictMatchState : + (ms->dictMatchState->dedicatedDictSearch ? ZSTD_dedicatedDictSearch : ZSTD_dictMatchState) : ZSTD_noDict; } +/* Defining this macro to non-zero tells zstd to run the overflow correction + * code much more frequently. This is very inefficient, and should only be + * used for tests and fuzzers. + */ +#ifndef ZSTD_WINDOW_OVERFLOW_CORRECT_FREQUENTLY +# ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION +# define ZSTD_WINDOW_OVERFLOW_CORRECT_FREQUENTLY 1 +# else +# define ZSTD_WINDOW_OVERFLOW_CORRECT_FREQUENTLY 0 +# endif +#endif + +/** + * ZSTD_window_canOverflowCorrect(): + * Returns non-zero if the indices are large enough for overflow correction + * to work correctly without impacting compression ratio. + */ +MEM_STATIC U32 ZSTD_window_canOverflowCorrect(ZSTD_window_t const window, + U32 cycleLog, + U32 maxDist, + U32 loadedDictEnd, + void const* src) +{ + U32 const cycleSize = 1u << cycleLog; + U32 const curr = (U32)((BYTE const*)src - window.base); + U32 const minIndexToOverflowCorrect = cycleSize + + MAX(maxDist, cycleSize) + + ZSTD_WINDOW_START_INDEX; + + /* Adjust the min index to backoff the overflow correction frequency, + * so we don't waste too much CPU in overflow correction. If this + * computation overflows we don't really care, we just need to make + * sure it is at least minIndexToOverflowCorrect. + */ + U32 const adjustment = window.nbOverflowCorrections + 1; + U32 const adjustedIndex = MAX(minIndexToOverflowCorrect * adjustment, + minIndexToOverflowCorrect); + U32 const indexLargeEnough = curr > adjustedIndex; + + /* Only overflow correct early if the dictionary is invalidated already, + * so we don't hurt compression ratio. + */ + U32 const dictionaryInvalidated = curr > maxDist + loadedDictEnd; + + return indexLargeEnough && dictionaryInvalidated; +} + /** * ZSTD_window_needOverflowCorrection(): * Returns non-zero if the indices are getting too large and need overflow * protection. */ MEM_STATIC U32 ZSTD_window_needOverflowCorrection(ZSTD_window_t const window, + U32 cycleLog, + U32 maxDist, + U32 loadedDictEnd, + void const* src, void const* srcEnd) { - U32 const current = (U32)((BYTE const*)srcEnd - window.base); - return current > ZSTD_CURRENT_MAX; + U32 const curr = (U32)((BYTE const*)srcEnd - window.base); + if (ZSTD_WINDOW_OVERFLOW_CORRECT_FREQUENTLY) { + if (ZSTD_window_canOverflowCorrect(window, cycleLog, maxDist, loadedDictEnd, src)) { + return 1; + } + } + return curr > ZSTD_CURRENT_MAX; } /** @@ -766,7 +1018,6 @@ MEM_STATIC U32 ZSTD_window_needOverflowCorrection(ZSTD_window_t const window, * * The least significant cycleLog bits of the indices must remain the same, * which may be 0. Every index up to maxDist in the past must be valid. - * NOTE: (maxDist & cycleMask) must be zero. */ MEM_STATIC U32 ZSTD_window_correctOverflow(ZSTD_window_t* window, U32 cycleLog, U32 maxDist, void const* src) @@ -790,32 +1041,52 @@ MEM_STATIC U32 ZSTD_window_correctOverflow(ZSTD_window_t* window, U32 cycleLog, * 3. (cctx->lowLimit + 1<<windowLog) < 1<<32: * windowLog <= 31 ==> 3<<29 + 1<<windowLog < 7<<29 < 1<<32. */ - U32 const cycleMask = (1U << cycleLog) - 1; - U32 const current = (U32)((BYTE const*)src - window->base); - U32 const currentCycle0 = current & cycleMask; - /* Exclude zero so that newCurrent - maxDist >= 1. */ - U32 const currentCycle1 = currentCycle0 == 0 ? (1U << cycleLog) : currentCycle0; - U32 const newCurrent = currentCycle1 + maxDist; - U32 const correction = current - newCurrent; - assert((maxDist & cycleMask) == 0); - assert(current > newCurrent); - /* Loose bound, should be around 1<<29 (see above) */ - assert(correction > 1<<28); + U32 const cycleSize = 1u << cycleLog; + U32 const cycleMask = cycleSize - 1; + U32 const curr = (U32)((BYTE const*)src - window->base); + U32 const currentCycle = curr & cycleMask; + /* Ensure newCurrent - maxDist >= ZSTD_WINDOW_START_INDEX. */ + U32 const currentCycleCorrection = currentCycle < ZSTD_WINDOW_START_INDEX + ? MAX(cycleSize, ZSTD_WINDOW_START_INDEX) + : 0; + U32 const newCurrent = currentCycle + + currentCycleCorrection + + MAX(maxDist, cycleSize); + U32 const correction = curr - newCurrent; + /* maxDist must be a power of two so that: + * (newCurrent & cycleMask) == (curr & cycleMask) + * This is required to not corrupt the chains / binary tree. + */ + assert((maxDist & (maxDist - 1)) == 0); + assert((curr & cycleMask) == (newCurrent & cycleMask)); + assert(curr > newCurrent); + if (!ZSTD_WINDOW_OVERFLOW_CORRECT_FREQUENTLY) { + /* Loose bound, should be around 1<<29 (see above) */ + assert(correction > 1<<28); + } window->base += correction; window->dictBase += correction; - if (window->lowLimit <= correction) window->lowLimit = 1; - else window->lowLimit -= correction; - if (window->dictLimit <= correction) window->dictLimit = 1; - else window->dictLimit -= correction; + if (window->lowLimit < correction + ZSTD_WINDOW_START_INDEX) { + window->lowLimit = ZSTD_WINDOW_START_INDEX; + } else { + window->lowLimit -= correction; + } + if (window->dictLimit < correction + ZSTD_WINDOW_START_INDEX) { + window->dictLimit = ZSTD_WINDOW_START_INDEX; + } else { + window->dictLimit -= correction; + } /* Ensure we can still reference the full window. */ assert(newCurrent >= maxDist); - assert(newCurrent - maxDist >= 1); + assert(newCurrent - maxDist >= ZSTD_WINDOW_START_INDEX); /* Ensure that lowLimit and dictLimit didn't underflow. */ assert(window->lowLimit <= newCurrent); assert(window->dictLimit <= newCurrent); + ++window->nbOverflowCorrections; + DEBUGLOG(4, "Correction of 0x%x bytes to lowLimit=0x%x", correction, window->lowLimit); return correction; @@ -904,10 +1175,15 @@ ZSTD_checkDictValidity(const ZSTD_window_t* window, (unsigned)blockEndIdx, (unsigned)maxDist, (unsigned)loadedDictEnd); assert(blockEndIdx >= loadedDictEnd); - if (blockEndIdx > loadedDictEnd + maxDist) { + if (blockEndIdx > loadedDictEnd + maxDist || loadedDictEnd != window->dictLimit) { /* On reaching window size, dictionaries are invalidated. * For simplification, if window size is reached anywhere within next block, * the dictionary is invalidated for the full block. + * + * We also have to invalidate the dictionary if ZSTD_window_update() has detected + * non-contiguous segments, which means that loadedDictEnd != window->dictLimit. + * loadedDictEnd may be 0, if forceWindow is true, but in that case we never use + * dictMatchState, so setting it to NULL is not a problem. */ DEBUGLOG(6, "invalidating dictionary for current block (distance > windowSize)"); *loadedDictEndPtr = 0; @@ -919,12 +1195,14 @@ ZSTD_checkDictValidity(const ZSTD_window_t* window, } MEM_STATIC void ZSTD_window_init(ZSTD_window_t* window) { - memset(window, 0, sizeof(*window)); - window->base = (BYTE const*)""; - window->dictBase = (BYTE const*)""; - window->dictLimit = 1; /* start from 1, so that 1st position is valid */ - window->lowLimit = 1; /* it ensures first and later CCtx usages compress the same */ - window->nextSrc = window->base + 1; /* see issue #1241 */ + ZSTD_memset(window, 0, sizeof(*window)); + window->base = (BYTE const*)" "; + window->dictBase = (BYTE const*)" "; + ZSTD_STATIC_ASSERT(ZSTD_DUBT_UNSORTED_MARK < ZSTD_WINDOW_START_INDEX); /* Start above ZSTD_DUBT_UNSORTED_MARK */ + window->dictLimit = ZSTD_WINDOW_START_INDEX; /* start from >0, so that 1st position is valid */ + window->lowLimit = ZSTD_WINDOW_START_INDEX; /* it ensures first and later CCtx usages compress the same */ + window->nextSrc = window->base + ZSTD_WINDOW_START_INDEX; /* see issue #1241 */ + window->nbOverflowCorrections = 0; } /** @@ -935,7 +1213,8 @@ MEM_STATIC void ZSTD_window_init(ZSTD_window_t* window) { * Returns non-zero if the segment is contiguous. */ MEM_STATIC U32 ZSTD_window_update(ZSTD_window_t* window, - void const* src, size_t srcSize) + void const* src, size_t srcSize, + int forceNonContiguous) { BYTE const* const ip = (BYTE const*)src; U32 contiguous = 1; @@ -945,7 +1224,7 @@ MEM_STATIC U32 ZSTD_window_update(ZSTD_window_t* window, assert(window->base != NULL); assert(window->dictBase != NULL); /* Check if blocks follow each other */ - if (src != window->nextSrc) { + if (src != window->nextSrc || forceNonContiguous) { /* not contiguous */ size_t const distanceFromBase = (size_t)(window->nextSrc - window->base); DEBUGLOG(5, "Non contiguous blocks, new segment starts at %u", window->dictLimit); @@ -973,25 +1252,32 @@ MEM_STATIC U32 ZSTD_window_update(ZSTD_window_t* window, /** * Returns the lowest allowed match index. It may either be in the ext-dict or the prefix. */ -MEM_STATIC U32 ZSTD_getLowestMatchIndex(const ZSTD_matchState_t* ms, U32 current, unsigned windowLog) +MEM_STATIC U32 ZSTD_getLowestMatchIndex(const ZSTD_matchState_t* ms, U32 curr, unsigned windowLog) { - U32 const maxDistance = 1U << windowLog; - U32 const lowestValid = ms->window.lowLimit; - U32 const withinWindow = (current - lowestValid > maxDistance) ? current - maxDistance : lowestValid; - U32 const isDictionary = (ms->loadedDictEnd != 0); - U32 const matchLowest = isDictionary ? lowestValid : withinWindow; + U32 const maxDistance = 1U << windowLog; + U32 const lowestValid = ms->window.lowLimit; + U32 const withinWindow = (curr - lowestValid > maxDistance) ? curr - maxDistance : lowestValid; + U32 const isDictionary = (ms->loadedDictEnd != 0); + /* When using a dictionary the entire dictionary is valid if a single byte of the dictionary + * is within the window. We invalidate the dictionary (and set loadedDictEnd to 0) when it isn't + * valid for the entire block. So this check is sufficient to find the lowest valid match index. + */ + U32 const matchLowest = isDictionary ? lowestValid : withinWindow; return matchLowest; } /** * Returns the lowest allowed match index in the prefix. */ -MEM_STATIC U32 ZSTD_getLowestPrefixIndex(const ZSTD_matchState_t* ms, U32 current, unsigned windowLog) +MEM_STATIC U32 ZSTD_getLowestPrefixIndex(const ZSTD_matchState_t* ms, U32 curr, unsigned windowLog) { U32 const maxDistance = 1U << windowLog; U32 const lowestValid = ms->window.dictLimit; - U32 const withinWindow = (current - lowestValid > maxDistance) ? current - maxDistance : lowestValid; + U32 const withinWindow = (curr - lowestValid > maxDistance) ? curr - maxDistance : lowestValid; U32 const isDictionary = (ms->loadedDictEnd != 0); + /* When computing the lowest prefix index we need to take the dictionary into account to handle + * the edge case where the dictionary and the source are contiguous in memory. + */ U32 const matchLowest = isDictionary ? lowestValid : withinWindow; return matchLowest; } @@ -1029,6 +1315,42 @@ MEM_STATIC void ZSTD_debugTable(const U32* table, U32 max) #endif +/* Short Cache */ + +/* Normally, zstd matchfinders follow this flow: + * 1. Compute hash at ip + * 2. Load index from hashTable[hash] + * 3. Check if *ip == *(base + index) + * In dictionary compression, loading *(base + index) is often an L2 or even L3 miss. + * + * Short cache is an optimization which allows us to avoid step 3 most of the time + * when the data doesn't actually match. With short cache, the flow becomes: + * 1. Compute (hash, currentTag) at ip. currentTag is an 8-bit independent hash at ip. + * 2. Load (index, matchTag) from hashTable[hash]. See ZSTD_writeTaggedIndex to understand how this works. + * 3. Only if currentTag == matchTag, check *ip == *(base + index). Otherwise, continue. + * + * Currently, short cache is only implemented in CDict hashtables. Thus, its use is limited to + * dictMatchState matchfinders. + */ +#define ZSTD_SHORT_CACHE_TAG_BITS 8 +#define ZSTD_SHORT_CACHE_TAG_MASK ((1u << ZSTD_SHORT_CACHE_TAG_BITS) - 1) + +/* Helper function for ZSTD_fillHashTable and ZSTD_fillDoubleHashTable. + * Unpacks hashAndTag into (hash, tag), then packs (index, tag) into hashTable[hash]. */ +MEM_STATIC void ZSTD_writeTaggedIndex(U32* const hashTable, size_t hashAndTag, U32 index) { + size_t const hash = hashAndTag >> ZSTD_SHORT_CACHE_TAG_BITS; + U32 const tag = (U32)(hashAndTag & ZSTD_SHORT_CACHE_TAG_MASK); + assert(index >> (32 - ZSTD_SHORT_CACHE_TAG_BITS) == 0); + hashTable[hash] = (index << ZSTD_SHORT_CACHE_TAG_BITS) | tag; +} + +/* Helper function for short cache matchfinders. + * Unpacks tag1 and tag2 from lower bits of packedTag1 and packedTag2, then checks if the tags match. */ +MEM_STATIC int ZSTD_comparePackedTags(size_t packedTag1, size_t packedTag2) { + U32 const tag1 = packedTag1 & ZSTD_SHORT_CACHE_TAG_MASK; + U32 const tag2 = packedTag2 & ZSTD_SHORT_CACHE_TAG_MASK; + return tag1 == tag2; +} #if defined (__cplusplus) } @@ -1045,7 +1367,6 @@ MEM_STATIC void ZSTD_debugTable(const U32* table, U32 max) * assumptions : magic number supposed already checked * and dictSize >= 8 */ size_t ZSTD_loadCEntropy(ZSTD_compressedBlockState_t* bs, void* workspace, - short* offcodeNCount, unsigned* offcodeMaxValue, const void* const dict, size_t dictSize); void ZSTD_reset_compressedBlockState(ZSTD_compressedBlockState_t* bs); @@ -1061,7 +1382,7 @@ void ZSTD_reset_compressedBlockState(ZSTD_compressedBlockState_t* bs); * Note: srcSizeHint == 0 means 0! */ ZSTD_compressionParameters ZSTD_getCParamsFromCCtxParams( - const ZSTD_CCtx_params* CCtxParams, U64 srcSizeHint, size_t dictSize); + const ZSTD_CCtx_params* CCtxParams, U64 srcSizeHint, size_t dictSize, ZSTD_cParamMode_e mode); /*! ZSTD_initCStream_internal() : * Private use only. Init streaming operation. @@ -1122,4 +1443,36 @@ size_t ZSTD_referenceExternalSequences(ZSTD_CCtx* cctx, rawSeq* seq, size_t nbSe * condition for correct operation : hashLog > 1 */ U32 ZSTD_cycleLog(U32 hashLog, ZSTD_strategy strat); +/** ZSTD_CCtx_trace() : + * Trace the end of a compression call. + */ +void ZSTD_CCtx_trace(ZSTD_CCtx* cctx, size_t extraCSize); + +/* Returns 0 on success, and a ZSTD_error otherwise. This function scans through an array of + * ZSTD_Sequence, storing the sequences it finds, until it reaches a block delimiter. + * Note that the block delimiter must include the last literals of the block. + */ +size_t +ZSTD_copySequencesToSeqStoreExplicitBlockDelim(ZSTD_CCtx* cctx, + ZSTD_sequencePosition* seqPos, + const ZSTD_Sequence* const inSeqs, size_t inSeqsSize, + const void* src, size_t blockSize, ZSTD_paramSwitch_e externalRepSearch); + +/* Returns the number of bytes to move the current read position back by. + * Only non-zero if we ended up splitting a sequence. + * Otherwise, it may return a ZSTD error if something went wrong. + * + * This function will attempt to scan through blockSize bytes + * represented by the sequences in @inSeqs, + * storing any (partial) sequences. + * + * Occasionally, we may want to change the actual number of bytes we consumed from inSeqs to + * avoid splitting a match, or to avoid splitting a match such that it would produce a match + * smaller than MINMATCH. In this case, we return the number of bytes that we didn't read from this block. + */ +size_t +ZSTD_copySequencesToSeqStoreNoBlockDelim(ZSTD_CCtx* cctx, ZSTD_sequencePosition* seqPos, + const ZSTD_Sequence* const inSeqs, size_t inSeqsSize, + const void* src, size_t blockSize, ZSTD_paramSwitch_e externalRepSearch); + #endif /* ZSTD_COMPRESS_H */ |