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Diffstat (limited to 'vendor/github.com/DataDog/zstd/zstd_compress_internal.h')
| -rw-r--r-- | vendor/github.com/DataDog/zstd/zstd_compress_internal.h | 863 |
1 files changed, 863 insertions, 0 deletions
diff --git a/vendor/github.com/DataDog/zstd/zstd_compress_internal.h b/vendor/github.com/DataDog/zstd/zstd_compress_internal.h new file mode 100644 index 000000000..cc3cbb9da --- /dev/null +++ b/vendor/github.com/DataDog/zstd/zstd_compress_internal.h @@ -0,0 +1,863 @@ +/* + * Copyright (c) 2016-present, Yann Collet, Facebook, Inc. + * All rights reserved. + * + * This source code is licensed under both the BSD-style license (found in the + * LICENSE file in the root directory of this source tree) and the GPLv2 (found + * in the COPYING file in the root directory of this source tree). + * You may select, at your option, one of the above-listed licenses. + */ + +/* This header contains definitions + * that shall **only** be used by modules within lib/compress. + */ + +#ifndef ZSTD_COMPRESS_H +#define ZSTD_COMPRESS_H + +/*-************************************* +* Dependencies +***************************************/ +#include "zstd_internal.h" +#ifdef ZSTD_MULTITHREAD +# include "zstdmt_compress.h" +#endif + +#if defined (__cplusplus) +extern "C" { +#endif + + +/*-************************************* +* Constants +***************************************/ +#define kSearchStrength 8 +#define HASH_READ_SIZE 8 +#define ZSTD_DUBT_UNSORTED_MARK 1 /* For btlazy2 strategy, index 1 now means "unsorted". + It could be confused for a real successor at index "1", if sorted as larger than its predecessor. + It's not a big deal though : candidate will just be sorted again. + Additionally, candidate position 1 will be lost. + But candidate 1 cannot hide a large tree of candidates, so it's a minimal loss. + The benefit is that ZSTD_DUBT_UNSORTED_MARK cannot be mishandled after table re-use with a different strategy + Constant required by ZSTD_compressBlock_btlazy2() and ZSTD_reduceTable_internal() */ + + +/*-************************************* +* Context memory management +***************************************/ +typedef enum { ZSTDcs_created=0, ZSTDcs_init, ZSTDcs_ongoing, ZSTDcs_ending } ZSTD_compressionStage_e; +typedef enum { zcss_init=0, zcss_load, zcss_flush } ZSTD_cStreamStage; + +typedef struct ZSTD_prefixDict_s { + const void* dict; + size_t dictSize; + ZSTD_dictContentType_e dictContentType; +} ZSTD_prefixDict; + +typedef struct { + void* dictBuffer; + void const* dict; + size_t dictSize; + ZSTD_dictContentType_e dictContentType; + ZSTD_CDict* cdict; +} ZSTD_localDict; + +typedef struct { + U32 CTable[HUF_CTABLE_SIZE_U32(255)]; + HUF_repeat repeatMode; +} ZSTD_hufCTables_t; + +typedef struct { + FSE_CTable offcodeCTable[FSE_CTABLE_SIZE_U32(OffFSELog, MaxOff)]; + FSE_CTable matchlengthCTable[FSE_CTABLE_SIZE_U32(MLFSELog, MaxML)]; + FSE_CTable litlengthCTable[FSE_CTABLE_SIZE_U32(LLFSELog, MaxLL)]; + FSE_repeat offcode_repeatMode; + FSE_repeat matchlength_repeatMode; + FSE_repeat litlength_repeatMode; +} ZSTD_fseCTables_t; + +typedef struct { + ZSTD_hufCTables_t huf; + ZSTD_fseCTables_t fse; +} ZSTD_entropyCTables_t; + +typedef struct { + U32 off; + U32 len; +} ZSTD_match_t; + +typedef struct { + int price; + U32 off; + U32 mlen; + U32 litlen; + U32 rep[ZSTD_REP_NUM]; +} ZSTD_optimal_t; + +typedef enum { zop_dynamic=0, zop_predef } ZSTD_OptPrice_e; + +typedef struct { + /* All tables are allocated inside cctx->workspace by ZSTD_resetCCtx_internal() */ + unsigned* litFreq; /* table of literals statistics, of size 256 */ + unsigned* litLengthFreq; /* table of litLength statistics, of size (MaxLL+1) */ + unsigned* matchLengthFreq; /* table of matchLength statistics, of size (MaxML+1) */ + unsigned* offCodeFreq; /* table of offCode statistics, of size (MaxOff+1) */ + ZSTD_match_t* matchTable; /* list of found matches, of size ZSTD_OPT_NUM+1 */ + ZSTD_optimal_t* priceTable; /* All positions tracked by optimal parser, of size ZSTD_OPT_NUM+1 */ + + U32 litSum; /* nb of literals */ + U32 litLengthSum; /* nb of litLength codes */ + U32 matchLengthSum; /* nb of matchLength codes */ + U32 offCodeSum; /* nb of offset codes */ + U32 litSumBasePrice; /* to compare to log2(litfreq) */ + U32 litLengthSumBasePrice; /* to compare to log2(llfreq) */ + U32 matchLengthSumBasePrice;/* to compare to log2(mlfreq) */ + 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; +} optState_t; + +typedef struct { + ZSTD_entropyCTables_t entropy; + U32 rep[ZSTD_REP_NUM]; +} 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 data */ +} ZSTD_window_t; + +typedef struct ZSTD_matchState_t ZSTD_matchState_t; +struct ZSTD_matchState_t { + ZSTD_window_t window; /* State for window round buffer management */ + U32 loadedDictEnd; /* index of end of dictionary */ + U32 nextToUpdate; /* index from which to continue table update */ + U32 nextToUpdate3; /* index from which to continue table update */ + U32 hashLog3; /* dispatch table : larger == faster, more memory */ + U32* hashTable; + U32* hashTable3; + U32* chainTable; + optState_t opt; /* optimal parser state */ + const ZSTD_matchState_t * dictMatchState; + ZSTD_compressionParameters cParams; +}; + +typedef struct { + ZSTD_compressedBlockState_t* prevCBlock; + ZSTD_compressedBlockState_t* nextCBlock; + ZSTD_matchState_t matchState; +} ZSTD_blockState_t; + +typedef struct { + U32 offset; + U32 checksum; +} ldmEntry_t; + +typedef struct { + ZSTD_window_t window; /* State for the window round buffer management */ + ldmEntry_t* hashTable; + BYTE* bucketOffsets; /* Next position in bucket to insert entry */ + U64 hashPower; /* Used to compute the rolling hash. + * Depends on ldmParams.minMatchLength */ +} ldmState_t; + +typedef struct { + U32 enableLdm; /* 1 if enable long distance matching */ + U32 hashLog; /* Log size of hashTable */ + U32 bucketSizeLog; /* Log bucket size for collision resolution, at most 8 */ + U32 minMatchLength; /* Minimum match length */ + U32 hashRateLog; /* Log number of entries to skip */ + U32 windowLog; /* Window log for the LDM */ +} 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; + +struct ZSTD_CCtx_params_s { + ZSTD_format_e format; + ZSTD_compressionParameters cParams; + ZSTD_frameParameters fParams; + + int compressionLevel; + int forceWindow; /* force back-references to respect limit of + * 1<<wLog, even for dictionary */ + + ZSTD_dictAttachPref_e attachDictPref; + ZSTD_literalCompressionMode_e literalCompressionMode; + + /* Multithreading: used to pass parameters to mtctx */ + int nbWorkers; + size_t jobSize; + int overlapLog; + int rsyncable; + + /* Long distance matching parameters */ + ldmParams_t ldmParams; + + /* Internal use, for createCCtxParams() and freeCCtxParams() only */ + ZSTD_customMem customMem; +}; /* typedef'd to ZSTD_CCtx_params within "zstd.h" */ + +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; + U32 dictID; + + int workSpaceOversizedDuration; + void* workSpace; + size_t workSpaceSize; + size_t blockSize; + unsigned long long pledgedSrcSizePlusOne; /* this way, 0 (default) == unknown */ + unsigned long long consumedSrcSize; + unsigned long long producedCSize; + XXH64_state_t xxhState; + ZSTD_customMem customMem; + size_t staticSize; + + seqStore_t seqStore; /* sequences storage ptrs */ + ldmState_t ldmState; /* long distance matching state */ + rawSeq* ldmSequences; /* Storage for the ldm output sequences */ + size_t maxNbLdmSequences; + rawSeqStore_t externSeqStore; /* Mutable reference to external sequences */ + ZSTD_blockState_t blockState; + U32* entropyWorkspace; /* entropy workspace of HUF_WORKSPACE_SIZE bytes */ + + /* streaming */ + char* inBuff; + size_t inBuffSize; + size_t inToCompress; + size_t inBuffPos; + size_t inBuffTarget; + char* outBuff; + size_t outBuffSize; + size_t outBuffContentSize; + size_t outBuffFlushedSize; + ZSTD_cStreamStage streamStage; + U32 frameEnded; + + /* Dictionary */ + ZSTD_localDict localDict; + const ZSTD_CDict* cdict; + ZSTD_prefixDict prefixDict; /* single-usage dictionary */ + + /* Multi-threading */ +#ifdef ZSTD_MULTITHREAD + ZSTDMT_CCtx* mtctx; +#endif +}; + +typedef enum { ZSTD_dtlm_fast, ZSTD_dtlm_full } ZSTD_dictTableLoadMethod_e; + +typedef enum { ZSTD_noDict = 0, ZSTD_extDict = 1, ZSTD_dictMatchState = 2 } ZSTD_dictMode_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); + + +MEM_STATIC U32 ZSTD_LLcode(U32 litLength) +{ + static const BYTE LL_Code[64] = { 0, 1, 2, 3, 4, 5, 6, 7, + 8, 9, 10, 11, 12, 13, 14, 15, + 16, 16, 17, 17, 18, 18, 19, 19, + 20, 20, 20, 20, 21, 21, 21, 21, + 22, 22, 22, 22, 22, 22, 22, 22, + 23, 23, 23, 23, 23, 23, 23, 23, + 24, 24, 24, 24, 24, 24, 24, 24, + 24, 24, 24, 24, 24, 24, 24, 24 }; + static const U32 LL_deltaCode = 19; + return (litLength > 63) ? ZSTD_highbit32(litLength) + LL_deltaCode : LL_Code[litLength]; +} + +/* ZSTD_MLcode() : + * note : mlBase = matchLength - MINMATCH; + * because it's the format it's stored in seqStore->sequences */ +MEM_STATIC U32 ZSTD_MLcode(U32 mlBase) +{ + static const BYTE ML_Code[128] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, + 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, + 32, 32, 33, 33, 34, 34, 35, 35, 36, 36, 36, 36, 37, 37, 37, 37, + 38, 38, 38, 38, 38, 38, 38, 38, 39, 39, 39, 39, 39, 39, 39, 39, + 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, + 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, + 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, + 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42 }; + static const U32 ML_deltaCode = 36; + return (mlBase > 127) ? ZSTD_highbit32(mlBase) + ML_deltaCode : ML_Code[mlBase]; +} + +/*! ZSTD_storeSeq() : + * Store a sequence (literal length, literals, offset code and match length code) into seqStore_t. + * `offsetCode` : distance to match + 3 (values 1-3 are repCodes). + * `mlBase` : matchLength - MINMATCH +*/ +MEM_STATIC void ZSTD_storeSeq(seqStore_t* seqStorePtr, size_t litLength, const void* literals, U32 offsetCode, size_t mlBase) +{ +#if defined(DEBUGLEVEL) && (DEBUGLEVEL >= 6) + 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)offsetCode); + } +#endif + assert((size_t)(seqStorePtr->sequences - seqStorePtr->sequencesStart) < seqStorePtr->maxNbSeq); + /* copy Literals */ + assert(seqStorePtr->maxNbLit <= 128 KB); + assert(seqStorePtr->lit + litLength <= seqStorePtr->litStart + seqStorePtr->maxNbLit); + ZSTD_wildcopy(seqStorePtr->lit, literals, litLength); + seqStorePtr->lit += litLength; + + /* literal Length */ + if (litLength>0xFFFF) { + assert(seqStorePtr->longLengthID == 0); /* there can only be a single long length */ + seqStorePtr->longLengthID = 1; + seqStorePtr->longLengthPos = (U32)(seqStorePtr->sequences - seqStorePtr->sequencesStart); + } + seqStorePtr->sequences[0].litLength = (U16)litLength; + + /* match offset */ + seqStorePtr->sequences[0].offset = offsetCode + 1; + + /* 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); + } + seqStorePtr->sequences[0].matchLength = (U16)mlBase; + + seqStorePtr->sequences++; +} + + +/*-************************************* +* Match length counter +***************************************/ +static unsigned ZSTD_NbCommonBytes (size_t val) +{ + if (MEM_isLittleEndian()) { + if (MEM_64bits()) { +# if defined(_MSC_VER) && defined(_WIN64) + unsigned long r = 0; + _BitScanForward64( &r, (U64)val ); + return (unsigned)(r>>3); +# 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; + _BitScanForward( &r, (U32)val ); + return (unsigned)(r>>3); +# 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 + } + } else { /* Big Endian CPU */ + if (MEM_64bits()) { +# if defined(_MSC_VER) && defined(_WIN64) + unsigned long r = 0; + _BitScanReverse64( &r, val ); + return (unsigned)(r>>3); +# 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; + _BitScanReverse( &r, (unsigned long)val ); + return (unsigned)(r>>3); +# 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 + } } +} + + +MEM_STATIC size_t ZSTD_count(const BYTE* pIn, const BYTE* pMatch, const BYTE* const pInLimit) +{ + const BYTE* const pStart = pIn; + const BYTE* const pInLoopLimit = pInLimit - (sizeof(size_t)-1); + + if (pIn < pInLoopLimit) { + { size_t const diff = MEM_readST(pMatch) ^ MEM_readST(pIn); + if (diff) return ZSTD_NbCommonBytes(diff); } + pIn+=sizeof(size_t); pMatch+=sizeof(size_t); + while (pIn < pInLoopLimit) { + size_t const diff = MEM_readST(pMatch) ^ MEM_readST(pIn); + if (!diff) { pIn+=sizeof(size_t); pMatch+=sizeof(size_t); continue; } + pIn += ZSTD_NbCommonBytes(diff); + return (size_t)(pIn - pStart); + } } + if (MEM_64bits() && (pIn<(pInLimit-3)) && (MEM_read32(pMatch) == MEM_read32(pIn))) { pIn+=4; pMatch+=4; } + if ((pIn<(pInLimit-1)) && (MEM_read16(pMatch) == MEM_read16(pIn))) { pIn+=2; pMatch+=2; } + if ((pIn<pInLimit) && (*pMatch == *pIn)) pIn++; + return (size_t)(pIn - pStart); +} + +/** ZSTD_count_2segments() : + * can count match length with `ip` & `match` in 2 different segments. + * convention : on reaching mEnd, match count continue starting from iStart + */ +MEM_STATIC size_t +ZSTD_count_2segments(const BYTE* ip, const BYTE* match, + const BYTE* iEnd, const BYTE* mEnd, const BYTE* iStart) +{ + const BYTE* const vEnd = MIN( ip + (mEnd - match), iEnd); + size_t const matchLength = ZSTD_count(ip, match, vEnd); + if (match + matchLength != mEnd) return matchLength; + DEBUGLOG(7, "ZSTD_count_2segments: found a 2-parts match (current length==%zu)", matchLength); + DEBUGLOG(7, "distance from match beginning to end dictionary = %zi", mEnd - match); + DEBUGLOG(7, "distance from current pos to end buffer = %zi", iEnd - ip); + DEBUGLOG(7, "next byte : ip==%02X, istart==%02X", ip[matchLength], *iStart); + DEBUGLOG(7, "final match length = %zu", matchLength + ZSTD_count(ip+matchLength, iStart, iEnd)); + return matchLength + ZSTD_count(ip+matchLength, iStart, iEnd); +} + + +/*-************************************* + * Hashes + ***************************************/ +static const U32 prime3bytes = 506832829U; +static U32 ZSTD_hash3(U32 u, U32 h) { 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 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_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_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_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_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) +{ + switch(mls) + { + default: + case 4: return ZSTD_hash4Ptr(p, hBits); + case 5: return ZSTD_hash5Ptr(p, hBits); + case 6: return ZSTD_hash6Ptr(p, hBits); + case 7: return ZSTD_hash7Ptr(p, hBits); + case 8: return ZSTD_hash8Ptr(p, hBits); + } +} + +/** ZSTD_ipow() : + * Return base^exponent. + */ +static U64 ZSTD_ipow(U64 base, U64 exponent) +{ + U64 power = 1; + while (exponent) { + if (exponent & 1) power *= base; + exponent >>= 1; + base *= base; + } + return power; +} + +#define ZSTD_ROLL_HASH_CHAR_OFFSET 10 + +/** ZSTD_rollingHash_append() : + * Add the buffer to the hash value. + */ +static U64 ZSTD_rollingHash_append(U64 hash, void const* buf, size_t size) +{ + BYTE const* istart = (BYTE const*)buf; + size_t pos; + for (pos = 0; pos < size; ++pos) { + hash *= prime8bytes; + hash += istart[pos] + ZSTD_ROLL_HASH_CHAR_OFFSET; + } + return hash; +} + +/** ZSTD_rollingHash_compute() : + * Compute the rolling hash value of the buffer. + */ +MEM_STATIC U64 ZSTD_rollingHash_compute(void const* buf, size_t size) +{ + return ZSTD_rollingHash_append(0, buf, size); +} + +/** ZSTD_rollingHash_primePower() : + * Compute the primePower to be passed to ZSTD_rollingHash_rotate() for a hash + * over a window of length bytes. + */ +MEM_STATIC U64 ZSTD_rollingHash_primePower(U32 length) +{ + return ZSTD_ipow(prime8bytes, length - 1); +} + +/** ZSTD_rollingHash_rotate() : + * Rotate the rolling hash by one byte. + */ +MEM_STATIC U64 ZSTD_rollingHash_rotate(U64 hash, BYTE toRemove, BYTE toAdd, U64 primePower) +{ + hash -= (toRemove + ZSTD_ROLL_HASH_CHAR_OFFSET) * primePower; + hash *= prime8bytes; + hash += toAdd + ZSTD_ROLL_HASH_CHAR_OFFSET; + return hash; +} + +/*-************************************* +* Round buffer management +***************************************/ +/* Max current allowed */ +#define ZSTD_CURRENT_MAX ((3U << 29) + (1U << ZSTD_WINDOWLOG_MAX)) +/* Maximum chunk size before overflow correction needs to be called again */ +#define ZSTD_CHUNKSIZE_MAX \ + ( ((U32)-1) /* Maximum ending current index */ \ + - ZSTD_CURRENT_MAX) /* Maximum beginning lowLimit */ + +/** + * ZSTD_window_clear(): + * Clears the window containing the history by simply setting it to empty. + */ +MEM_STATIC void ZSTD_window_clear(ZSTD_window_t* window) +{ + size_t const endT = (size_t)(window->nextSrc - window->base); + U32 const end = (U32)endT; + + window->lowLimit = end; + window->dictLimit = end; +} + +/** + * ZSTD_window_hasExtDict(): + * Returns non-zero if the window has a non-empty extDict. + */ +MEM_STATIC U32 ZSTD_window_hasExtDict(ZSTD_window_t const window) +{ + return window.lowLimit < window.dictLimit; +} + +/** + * ZSTD_matchState_dictMode(): + * Inspects the provided matchState and figures out what dictMode should be + * passed to the compressor. + */ +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 : + ZSTD_noDict; +} + +/** + * 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, + void const* srcEnd) +{ + U32 const current = (U32)((BYTE const*)srcEnd - window.base); + return current > ZSTD_CURRENT_MAX; +} + +/** + * ZSTD_window_correctOverflow(): + * Reduces the indices to protect from index overflow. + * Returns the correction made to the indices, which must be applied to every + * stored index. + * + * 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) +{ + /* preemptive overflow correction: + * 1. correction is large enough: + * lowLimit > (3<<29) ==> current > 3<<29 + 1<<windowLog + * 1<<windowLog <= newCurrent < 1<<chainLog + 1<<windowLog + * + * current - newCurrent + * > (3<<29 + 1<<windowLog) - (1<<windowLog + 1<<chainLog) + * > (3<<29) - (1<<chainLog) + * > (3<<29) - (1<<30) (NOTE: chainLog <= 30) + * > 1<<29 + * + * 2. (ip+ZSTD_CHUNKSIZE_MAX - cctx->base) doesn't overflow: + * After correction, current is less than (1<<chainLog + 1<<windowLog). + * In 64-bit mode we are safe, because we have 64-bit ptrdiff_t. + * In 32-bit mode we are safe, because (chainLog <= 29), so + * ip+ZSTD_CHUNKSIZE_MAX - cctx->base < 1<<32. + * 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 newCurrent = (current & cycleMask) + 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); + + window->base += correction; + window->dictBase += correction; + window->lowLimit -= correction; + window->dictLimit -= correction; + + DEBUGLOG(4, "Correction of 0x%x bytes to lowLimit=0x%x", correction, + window->lowLimit); + return correction; +} + +/** + * ZSTD_window_enforceMaxDist(): + * Updates lowLimit so that: + * (srcEnd - base) - lowLimit == maxDist + loadedDictEnd + * + * This allows a simple check that index >= lowLimit to see if index is valid. + * This must be called before a block compression call, with srcEnd as the block + * source end. + * + * If loadedDictEndPtr is not NULL, we set it to zero once we update lowLimit. + * This is because dictionaries are allowed to be referenced as long as the last + * byte of the dictionary is in the window, but once they are out of range, + * they cannot be referenced. If loadedDictEndPtr is NULL, we use + * loadedDictEnd == 0. + * + * In normal dict mode, the dict is between lowLimit and dictLimit. In + * dictMatchState mode, lowLimit and dictLimit are the same, and the dictionary + * is below them. forceWindow and dictMatchState are therefore incompatible. + */ +MEM_STATIC void +ZSTD_window_enforceMaxDist(ZSTD_window_t* window, + void const* srcEnd, + U32 maxDist, + U32* loadedDictEndPtr, + const ZSTD_matchState_t** dictMatchStatePtr) +{ + U32 const blockEndIdx = (U32)((BYTE const*)srcEnd - window->base); + U32 loadedDictEnd = (loadedDictEndPtr != NULL) ? *loadedDictEndPtr : 0; + DEBUGLOG(5, "ZSTD_window_enforceMaxDist: blockEndIdx=%u, maxDist=%u", + (unsigned)blockEndIdx, (unsigned)maxDist); + if (blockEndIdx > maxDist + loadedDictEnd) { + U32 const newLowLimit = blockEndIdx - maxDist; + if (window->lowLimit < newLowLimit) window->lowLimit = newLowLimit; + if (window->dictLimit < window->lowLimit) { + DEBUGLOG(5, "Update dictLimit to match lowLimit, from %u to %u", + (unsigned)window->dictLimit, (unsigned)window->lowLimit); + window->dictLimit = window->lowLimit; + } + if (loadedDictEndPtr) + *loadedDictEndPtr = 0; + if (dictMatchStatePtr) + *dictMatchStatePtr = NULL; + } +} + +/** + * ZSTD_window_update(): + * Updates the window by appending [src, src + srcSize) to the window. + * If it is not contiguous, the current prefix becomes the extDict, and we + * forget about the extDict. Handles overlap of the prefix and extDict. + * Returns non-zero if the segment is contiguous. + */ +MEM_STATIC U32 ZSTD_window_update(ZSTD_window_t* window, + void const* src, size_t srcSize) +{ + BYTE const* const ip = (BYTE const*)src; + U32 contiguous = 1; + DEBUGLOG(5, "ZSTD_window_update"); + /* Check if blocks follow each other */ + if (src != window->nextSrc) { + /* not contiguous */ + size_t const distanceFromBase = (size_t)(window->nextSrc - window->base); + DEBUGLOG(5, "Non contiguous blocks, new segment starts at %u", window->dictLimit); + window->lowLimit = window->dictLimit; + assert(distanceFromBase == (size_t)(U32)distanceFromBase); /* should never overflow */ + window->dictLimit = (U32)distanceFromBase; + window->dictBase = window->base; + window->base = ip - distanceFromBase; + // ms->nextToUpdate = window->dictLimit; + if (window->dictLimit - window->lowLimit < HASH_READ_SIZE) window->lowLimit = window->dictLimit; /* too small extDict */ + contiguous = 0; + } + window->nextSrc = ip + srcSize; + /* if input and dictionary overlap : reduce dictionary (area presumed modified by input) */ + if ( (ip+srcSize > window->dictBase + window->lowLimit) + & (ip < window->dictBase + window->dictLimit)) { + ptrdiff_t const highInputIdx = (ip + srcSize) - window->dictBase; + U32 const lowLimitMax = (highInputIdx > (ptrdiff_t)window->dictLimit) ? window->dictLimit : (U32)highInputIdx; + window->lowLimit = lowLimitMax; + DEBUGLOG(5, "Overlapping extDict and input : new lowLimit = %u", window->lowLimit); + } + return contiguous; +} + + +/* debug functions */ +#if (DEBUGLEVEL>=2) + +MEM_STATIC double ZSTD_fWeight(U32 rawStat) +{ + U32 const fp_accuracy = 8; + U32 const fp_multiplier = (1 << fp_accuracy); + U32 const newStat = rawStat + 1; + U32 const hb = ZSTD_highbit32(newStat); + U32 const BWeight = hb * fp_multiplier; + U32 const FWeight = (newStat << fp_accuracy) >> hb; + U32 const weight = BWeight + FWeight; + assert(hb + fp_accuracy < 31); + return (double)weight / fp_multiplier; +} + +/* display a table content, + * listing each element, its frequency, and its predicted bit cost */ +MEM_STATIC void ZSTD_debugTable(const U32* table, U32 max) +{ + unsigned u, sum; + for (u=0, sum=0; u<=max; u++) sum += table[u]; + DEBUGLOG(2, "total nb elts: %u", sum); + for (u=0; u<=max; u++) { + DEBUGLOG(2, "%2u: %5u (%.2f)", + u, table[u], ZSTD_fWeight(sum) - ZSTD_fWeight(table[u]) ); + } +} + +#endif + + +#if defined (__cplusplus) +} +#endif + + +/* ============================================================== + * Private declarations + * These prototypes shall only be called from within lib/compress + * ============================================================== */ + +/* ZSTD_getCParamsFromCCtxParams() : + * cParams are built depending on compressionLevel, src size hints, + * LDM and manually set compression parameters. + */ +ZSTD_compressionParameters ZSTD_getCParamsFromCCtxParams( + const ZSTD_CCtx_params* CCtxParams, U64 srcSizeHint, size_t dictSize); + +/*! ZSTD_initCStream_internal() : + * Private use only. Init streaming operation. + * expects params to be valid. + * must receive dict, or cdict, or none, but not both. + * @return : 0, or an error code */ +size_t ZSTD_initCStream_internal(ZSTD_CStream* zcs, + const void* dict, size_t dictSize, + const ZSTD_CDict* cdict, + ZSTD_CCtx_params params, unsigned long long pledgedSrcSize); + +void ZSTD_resetSeqStore(seqStore_t* ssPtr); + +/*! ZSTD_getCParamsFromCDict() : + * as the name implies */ +ZSTD_compressionParameters ZSTD_getCParamsFromCDict(const ZSTD_CDict* cdict); + +/* ZSTD_compressBegin_advanced_internal() : + * Private use only. To be called from zstdmt_compress.c. */ +size_t ZSTD_compressBegin_advanced_internal(ZSTD_CCtx* cctx, + const void* dict, size_t dictSize, + ZSTD_dictContentType_e dictContentType, + ZSTD_dictTableLoadMethod_e dtlm, + const ZSTD_CDict* cdict, + ZSTD_CCtx_params params, + unsigned long long pledgedSrcSize); + +/* ZSTD_compress_advanced_internal() : + * Private use only. To be called from zstdmt_compress.c. */ +size_t ZSTD_compress_advanced_internal(ZSTD_CCtx* cctx, + void* dst, size_t dstCapacity, + const void* src, size_t srcSize, + const void* dict,size_t dictSize, + ZSTD_CCtx_params params); + + +/* ZSTD_writeLastEmptyBlock() : + * output an empty Block with end-of-frame mark to complete a frame + * @return : size of data written into `dst` (== ZSTD_blockHeaderSize (defined in zstd_internal.h)) + * or an error code if `dstCapacity` is too small (<ZSTD_blockHeaderSize) + */ +size_t ZSTD_writeLastEmptyBlock(void* dst, size_t dstCapacity); + + +/* ZSTD_referenceExternalSequences() : + * Must be called before starting a compression operation. + * seqs must parse a prefix of the source. + * This cannot be used when long range matching is enabled. + * Zstd will use these sequences, and pass the literals to a secondary block + * compressor. + * @return : An error code on failure. + * NOTE: seqs are not verified! Invalid sequences can cause out-of-bounds memory + * access and data corruption. + */ +size_t ZSTD_referenceExternalSequences(ZSTD_CCtx* cctx, rawSeq* seq, size_t nbSeq); + + +#endif /* ZSTD_COMPRESS_H */ |