mirror of
https://github.com/Sarsoo/csbindgen.git
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1479 lines
60 KiB
C
1479 lines
60 KiB
C
/*
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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* All rights reserved.
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*
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* This source code is licensed under both the BSD-style license (found in the
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* LICENSE file in the root directory of this source tree) and the GPLv2 (found
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* in the COPYING file in the root directory of this source tree).
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* You may select, at your option, one of the above-listed licenses.
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*/
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/* This header contains definitions
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* that shall **only** be used by modules within lib/compress.
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*/
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#ifndef ZSTD_COMPRESS_H
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#define ZSTD_COMPRESS_H
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/*-*************************************
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* Dependencies
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***************************************/
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#include "../common/zstd_internal.h"
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#include "zstd_cwksp.h"
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#ifdef ZSTD_MULTITHREAD
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# include "zstdmt_compress.h"
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#endif
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#include "../common/bits.h" /* ZSTD_highbit32, ZSTD_NbCommonBytes */
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#if defined (__cplusplus)
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extern "C" {
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#endif
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/*-*************************************
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* Constants
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***************************************/
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#define kSearchStrength 8
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#define HASH_READ_SIZE 8
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#define ZSTD_DUBT_UNSORTED_MARK 1 /* For btlazy2 strategy, index ZSTD_DUBT_UNSORTED_MARK==1 means "unsorted".
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It could be confused for a real successor at index "1", if sorted as larger than its predecessor.
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It's not a big deal though : candidate will just be sorted again.
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Additionally, candidate position 1 will be lost.
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But candidate 1 cannot hide a large tree of candidates, so it's a minimal loss.
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The benefit is that ZSTD_DUBT_UNSORTED_MARK cannot be mishandled after table re-use with a different strategy.
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This constant is required by ZSTD_compressBlock_btlazy2() and ZSTD_reduceTable_internal() */
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/*-*************************************
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* Context memory management
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***************************************/
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typedef enum { ZSTDcs_created=0, ZSTDcs_init, ZSTDcs_ongoing, ZSTDcs_ending } ZSTD_compressionStage_e;
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typedef enum { zcss_init=0, zcss_load, zcss_flush } ZSTD_cStreamStage;
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typedef struct ZSTD_prefixDict_s {
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const void* dict;
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size_t dictSize;
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ZSTD_dictContentType_e dictContentType;
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} ZSTD_prefixDict;
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typedef struct {
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void* dictBuffer;
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void const* dict;
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size_t dictSize;
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ZSTD_dictContentType_e dictContentType;
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ZSTD_CDict* cdict;
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} ZSTD_localDict;
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typedef struct {
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HUF_CElt CTable[HUF_CTABLE_SIZE_ST(255)];
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HUF_repeat repeatMode;
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} ZSTD_hufCTables_t;
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typedef struct {
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FSE_CTable offcodeCTable[FSE_CTABLE_SIZE_U32(OffFSELog, MaxOff)];
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FSE_CTable matchlengthCTable[FSE_CTABLE_SIZE_U32(MLFSELog, MaxML)];
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FSE_CTable litlengthCTable[FSE_CTABLE_SIZE_U32(LLFSELog, MaxLL)];
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FSE_repeat offcode_repeatMode;
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FSE_repeat matchlength_repeatMode;
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FSE_repeat litlength_repeatMode;
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} ZSTD_fseCTables_t;
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typedef struct {
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ZSTD_hufCTables_t huf;
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ZSTD_fseCTables_t fse;
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} ZSTD_entropyCTables_t;
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/***********************************************
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* Entropy buffer statistics structs and funcs *
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***********************************************/
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/** ZSTD_hufCTablesMetadata_t :
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* Stores Literals Block Type for a super-block in hType, and
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* huffman tree description in hufDesBuffer.
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* hufDesSize refers to the size of huffman tree description in bytes.
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* This metadata is populated in ZSTD_buildBlockEntropyStats_literals() */
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typedef struct {
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symbolEncodingType_e hType;
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BYTE hufDesBuffer[ZSTD_MAX_HUF_HEADER_SIZE];
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size_t hufDesSize;
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} ZSTD_hufCTablesMetadata_t;
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/** ZSTD_fseCTablesMetadata_t :
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* Stores symbol compression modes for a super-block in {ll, ol, ml}Type, and
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* fse tables in fseTablesBuffer.
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* fseTablesSize refers to the size of fse tables in bytes.
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* This metadata is populated in ZSTD_buildBlockEntropyStats_sequences() */
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typedef struct {
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symbolEncodingType_e llType;
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symbolEncodingType_e ofType;
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symbolEncodingType_e mlType;
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BYTE fseTablesBuffer[ZSTD_MAX_FSE_HEADERS_SIZE];
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size_t fseTablesSize;
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size_t lastCountSize; /* This is to account for bug in 1.3.4. More detail in ZSTD_entropyCompressSeqStore_internal() */
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} ZSTD_fseCTablesMetadata_t;
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typedef struct {
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ZSTD_hufCTablesMetadata_t hufMetadata;
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ZSTD_fseCTablesMetadata_t fseMetadata;
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} ZSTD_entropyCTablesMetadata_t;
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/** ZSTD_buildBlockEntropyStats() :
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* Builds entropy for the block.
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* @return : 0 on success or error code */
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size_t ZSTD_buildBlockEntropyStats(
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const seqStore_t* seqStorePtr,
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const ZSTD_entropyCTables_t* prevEntropy,
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ZSTD_entropyCTables_t* nextEntropy,
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const ZSTD_CCtx_params* cctxParams,
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ZSTD_entropyCTablesMetadata_t* entropyMetadata,
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void* workspace, size_t wkspSize);
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/*********************************
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* Compression internals structs *
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*********************************/
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typedef struct {
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U32 off; /* Offset sumtype code for the match, using ZSTD_storeSeq() format */
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U32 len; /* Raw length of match */
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} ZSTD_match_t;
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typedef struct {
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U32 offset; /* Offset of sequence */
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U32 litLength; /* Length of literals prior to match */
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U32 matchLength; /* Raw length of match */
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} rawSeq;
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typedef struct {
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rawSeq* seq; /* The start of the sequences */
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size_t pos; /* The index in seq where reading stopped. pos <= size. */
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size_t posInSequence; /* The position within the sequence at seq[pos] where reading
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stopped. posInSequence <= seq[pos].litLength + seq[pos].matchLength */
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size_t size; /* The number of sequences. <= capacity. */
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size_t capacity; /* The capacity starting from `seq` pointer */
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} rawSeqStore_t;
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typedef struct {
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U32 idx; /* Index in array of ZSTD_Sequence */
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U32 posInSequence; /* Position within sequence at idx */
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size_t posInSrc; /* Number of bytes given by sequences provided so far */
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} ZSTD_sequencePosition;
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UNUSED_ATTR static const rawSeqStore_t kNullRawSeqStore = {NULL, 0, 0, 0, 0};
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typedef struct {
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int price;
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U32 off;
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U32 mlen;
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U32 litlen;
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U32 rep[ZSTD_REP_NUM];
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} ZSTD_optimal_t;
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typedef enum { zop_dynamic=0, zop_predef } ZSTD_OptPrice_e;
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typedef struct {
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/* All tables are allocated inside cctx->workspace by ZSTD_resetCCtx_internal() */
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unsigned* litFreq; /* table of literals statistics, of size 256 */
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unsigned* litLengthFreq; /* table of litLength statistics, of size (MaxLL+1) */
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unsigned* matchLengthFreq; /* table of matchLength statistics, of size (MaxML+1) */
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unsigned* offCodeFreq; /* table of offCode statistics, of size (MaxOff+1) */
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ZSTD_match_t* matchTable; /* list of found matches, of size ZSTD_OPT_NUM+1 */
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ZSTD_optimal_t* priceTable; /* All positions tracked by optimal parser, of size ZSTD_OPT_NUM+1 */
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U32 litSum; /* nb of literals */
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U32 litLengthSum; /* nb of litLength codes */
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U32 matchLengthSum; /* nb of matchLength codes */
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U32 offCodeSum; /* nb of offset codes */
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U32 litSumBasePrice; /* to compare to log2(litfreq) */
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U32 litLengthSumBasePrice; /* to compare to log2(llfreq) */
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U32 matchLengthSumBasePrice;/* to compare to log2(mlfreq) */
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U32 offCodeSumBasePrice; /* to compare to log2(offreq) */
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ZSTD_OptPrice_e priceType; /* prices can be determined dynamically, or follow a pre-defined cost structure */
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const ZSTD_entropyCTables_t* symbolCosts; /* pre-calculated dictionary statistics */
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ZSTD_paramSwitch_e literalCompressionMode;
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} optState_t;
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typedef struct {
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ZSTD_entropyCTables_t entropy;
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U32 rep[ZSTD_REP_NUM];
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} ZSTD_compressedBlockState_t;
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typedef struct {
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BYTE const* nextSrc; /* next block here to continue on current prefix */
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BYTE const* base; /* All regular indexes relative to this position */
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BYTE const* dictBase; /* extDict indexes relative to this position */
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U32 dictLimit; /* below that point, need extDict */
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U32 lowLimit; /* below that point, no more valid data */
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U32 nbOverflowCorrections; /* Number of times overflow correction has run since
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* ZSTD_window_init(). Useful for debugging coredumps
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* and for ZSTD_WINDOW_OVERFLOW_CORRECT_FREQUENTLY.
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*/
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} ZSTD_window_t;
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#define ZSTD_WINDOW_START_INDEX 2
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typedef struct ZSTD_matchState_t ZSTD_matchState_t;
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#define ZSTD_ROW_HASH_CACHE_SIZE 8 /* Size of prefetching hash cache for row-based matchfinder */
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struct ZSTD_matchState_t {
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ZSTD_window_t window; /* State for window round buffer management */
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U32 loadedDictEnd; /* index of end of dictionary, within context's referential.
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* When loadedDictEnd != 0, a dictionary is in use, and still valid.
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* This relies on a mechanism to set loadedDictEnd=0 when dictionary is no longer within distance.
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* Such mechanism is provided within ZSTD_window_enforceMaxDist() and ZSTD_checkDictValidity().
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* When dict referential is copied into active context (i.e. not attached),
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* loadedDictEnd == dictSize, since referential starts from zero.
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*/
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U32 nextToUpdate; /* index from which to continue table update */
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U32 hashLog3; /* dispatch table for matches of len==3 : larger == faster, more memory */
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U32 rowHashLog; /* For row-based matchfinder: Hashlog based on nb of rows in the hashTable.*/
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U16* tagTable; /* For row-based matchFinder: A row-based table containing the hashes and head index. */
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U32 hashCache[ZSTD_ROW_HASH_CACHE_SIZE]; /* For row-based matchFinder: a cache of hashes to improve speed */
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U32* hashTable;
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U32* hashTable3;
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U32* chainTable;
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U32 forceNonContiguous; /* Non-zero if we should force non-contiguous load for the next window update. */
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int dedicatedDictSearch; /* Indicates whether this matchState is using the
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* dedicated dictionary search structure.
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*/
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optState_t opt; /* optimal parser state */
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const ZSTD_matchState_t* dictMatchState;
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ZSTD_compressionParameters cParams;
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const rawSeqStore_t* ldmSeqStore;
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/* Controls prefetching in some dictMatchState matchfinders.
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* This behavior is controlled from the cctx ms.
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* This parameter has no effect in the cdict ms. */
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int prefetchCDictTables;
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};
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typedef struct {
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ZSTD_compressedBlockState_t* prevCBlock;
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ZSTD_compressedBlockState_t* nextCBlock;
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ZSTD_matchState_t matchState;
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} ZSTD_blockState_t;
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typedef struct {
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U32 offset;
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U32 checksum;
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} ldmEntry_t;
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typedef struct {
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BYTE const* split;
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U32 hash;
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U32 checksum;
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ldmEntry_t* bucket;
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} ldmMatchCandidate_t;
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#define LDM_BATCH_SIZE 64
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typedef struct {
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ZSTD_window_t window; /* State for the window round buffer management */
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ldmEntry_t* hashTable;
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U32 loadedDictEnd;
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BYTE* bucketOffsets; /* Next position in bucket to insert entry */
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size_t splitIndices[LDM_BATCH_SIZE];
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ldmMatchCandidate_t matchCandidates[LDM_BATCH_SIZE];
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} ldmState_t;
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typedef struct {
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ZSTD_paramSwitch_e enableLdm; /* ZSTD_ps_enable to enable LDM. ZSTD_ps_auto by default */
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U32 hashLog; /* Log size of hashTable */
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U32 bucketSizeLog; /* Log bucket size for collision resolution, at most 8 */
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U32 minMatchLength; /* Minimum match length */
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U32 hashRateLog; /* Log number of entries to skip */
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U32 windowLog; /* Window log for the LDM */
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} ldmParams_t;
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typedef struct {
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int collectSequences;
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ZSTD_Sequence* seqStart;
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size_t seqIndex;
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size_t maxSequences;
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} SeqCollector;
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struct ZSTD_CCtx_params_s {
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ZSTD_format_e format;
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ZSTD_compressionParameters cParams;
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ZSTD_frameParameters fParams;
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int compressionLevel;
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int forceWindow; /* force back-references to respect limit of
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* 1<<wLog, even for dictionary */
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size_t targetCBlockSize; /* Tries to fit compressed block size to be around targetCBlockSize.
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* No target when targetCBlockSize == 0.
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* There is no guarantee on compressed block size */
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int srcSizeHint; /* User's best guess of source size.
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* Hint is not valid when srcSizeHint == 0.
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* There is no guarantee that hint is close to actual source size */
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ZSTD_dictAttachPref_e attachDictPref;
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ZSTD_paramSwitch_e literalCompressionMode;
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/* Multithreading: used to pass parameters to mtctx */
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int nbWorkers;
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size_t jobSize;
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int overlapLog;
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int rsyncable;
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/* Long distance matching parameters */
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ldmParams_t ldmParams;
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/* Dedicated dict search algorithm trigger */
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int enableDedicatedDictSearch;
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/* Input/output buffer modes */
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ZSTD_bufferMode_e inBufferMode;
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ZSTD_bufferMode_e outBufferMode;
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/* Sequence compression API */
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ZSTD_sequenceFormat_e blockDelimiters;
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int validateSequences;
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/* Block splitting */
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ZSTD_paramSwitch_e useBlockSplitter;
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/* Param for deciding whether to use row-based matchfinder */
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ZSTD_paramSwitch_e useRowMatchFinder;
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/* Always load a dictionary in ext-dict mode (not prefix mode)? */
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int deterministicRefPrefix;
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/* Internal use, for createCCtxParams() and freeCCtxParams() only */
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ZSTD_customMem customMem;
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/* Controls prefetching in some dictMatchState matchfinders */
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ZSTD_paramSwitch_e prefetchCDictTables;
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/* Controls whether zstd will fall back to an internal matchfinder
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* if the external matchfinder returns an error code. */
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int enableMatchFinderFallback;
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/* Indicates whether an external matchfinder has been referenced.
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* Users can't set this externally.
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* It is set internally in ZSTD_registerSequenceProducer(). */
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int useSequenceProducer;
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/* Adjust the max block size*/
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size_t maxBlockSize;
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/* Controls repcode search in external sequence parsing */
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ZSTD_paramSwitch_e searchForExternalRepcodes;
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}; /* typedef'd to ZSTD_CCtx_params within "zstd.h" */
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#define COMPRESS_SEQUENCES_WORKSPACE_SIZE (sizeof(unsigned) * (MaxSeq + 2))
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#define ENTROPY_WORKSPACE_SIZE (HUF_WORKSPACE_SIZE + COMPRESS_SEQUENCES_WORKSPACE_SIZE)
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/**
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* Indicates whether this compression proceeds directly from user-provided
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* source buffer to user-provided destination buffer (ZSTDb_not_buffered), or
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* whether the context needs to buffer the input/output (ZSTDb_buffered).
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*/
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typedef enum {
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ZSTDb_not_buffered,
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ZSTDb_buffered
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} ZSTD_buffered_policy_e;
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/**
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* Struct that contains all elements of block splitter that should be allocated
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* in a wksp.
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*/
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#define ZSTD_MAX_NB_BLOCK_SPLITS 196
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typedef struct {
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seqStore_t fullSeqStoreChunk;
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seqStore_t firstHalfSeqStore;
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seqStore_t secondHalfSeqStore;
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seqStore_t currSeqStore;
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seqStore_t nextSeqStore;
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U32 partitions[ZSTD_MAX_NB_BLOCK_SPLITS];
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ZSTD_entropyCTablesMetadata_t entropyMetadata;
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} ZSTD_blockSplitCtx;
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/* Context for block-level external matchfinder API */
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typedef struct {
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void* mState;
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ZSTD_sequenceProducer_F* mFinder;
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ZSTD_Sequence* seqBuffer;
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size_t seqBufferCapacity;
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} ZSTD_externalMatchCtx;
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struct ZSTD_CCtx_s {
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ZSTD_compressionStage_e stage;
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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. */
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int bmi2; /* == 1 if the CPU supports BMI2 and 0 otherwise. CPU support is determined dynamically once per context lifetime. */
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ZSTD_CCtx_params requestedParams;
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ZSTD_CCtx_params appliedParams;
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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. */
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U32 dictID;
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size_t dictContentSize;
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ZSTD_cwksp workspace; /* manages buffer for dynamic allocations */
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size_t blockSize;
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unsigned long long pledgedSrcSizePlusOne; /* this way, 0 (default) == unknown */
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unsigned long long consumedSrcSize;
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unsigned long long producedCSize;
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XXH64_state_t xxhState;
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ZSTD_customMem customMem;
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ZSTD_threadPool* pool;
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size_t staticSize;
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SeqCollector seqCollector;
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int isFirstBlock;
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int initialized;
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seqStore_t seqStore; /* sequences storage ptrs */
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ldmState_t ldmState; /* long distance matching state */
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rawSeq* ldmSequences; /* Storage for the ldm output sequences */
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size_t maxNbLdmSequences;
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rawSeqStore_t externSeqStore; /* Mutable reference to external sequences */
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ZSTD_blockState_t blockState;
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U32* entropyWorkspace; /* entropy workspace of ENTROPY_WORKSPACE_SIZE bytes */
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/* Whether we are streaming or not */
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ZSTD_buffered_policy_e bufferedPolicy;
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/* streaming */
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char* inBuff;
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size_t inBuffSize;
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size_t inToCompress;
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size_t inBuffPos;
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size_t inBuffTarget;
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char* outBuff;
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size_t outBuffSize;
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size_t outBuffContentSize;
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size_t outBuffFlushedSize;
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ZSTD_cStreamStage streamStage;
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U32 frameEnded;
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/* Stable in/out buffer verification */
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ZSTD_inBuffer expectedInBuffer;
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size_t stableIn_notConsumed; /* nb bytes within stable input buffer that are said to be consumed but are not */
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size_t expectedOutBufferSize;
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/* Dictionary */
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ZSTD_localDict localDict;
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const ZSTD_CDict* cdict;
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ZSTD_prefixDict prefixDict; /* single-usage dictionary */
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/* Multi-threading */
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#ifdef ZSTD_MULTITHREAD
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ZSTDMT_CCtx* mtctx;
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#endif
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/* Tracing */
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#if ZSTD_TRACE
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ZSTD_TraceCtx traceCtx;
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#endif
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/* Workspace for block splitter */
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ZSTD_blockSplitCtx blockSplitCtx;
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|
|
|
/* 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_paramSwitch_e rowMatchfinderMode, 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_cParam_withinBounds:
|
|
* @return 1 if value is within cParam bounds,
|
|
* 0 otherwise */
|
|
MEM_STATIC int ZSTD_cParam_withinBounds(ZSTD_cParameter cParam, int value)
|
|
{
|
|
ZSTD_bounds const bounds = ZSTD_cParam_getBounds(cParam);
|
|
if (ZSTD_isError(bounds.error)) return 0;
|
|
if (value < bounds.lowerBound) return 0;
|
|
if (value > bounds.upperBound) return 0;
|
|
return 1;
|
|
}
|
|
|
|
/* 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)
|
|
{
|
|
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);
|
|
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)
|
|
{
|
|
BYTE* const op = (BYTE*)dst;
|
|
U32 const cBlockHeader = lastBlock + (((U32)bt_rle)<<1) + (U32)(srcSize << 3);
|
|
RETURN_ERROR_IF(dstCapacity < 4, dstSize_tooSmall, "");
|
|
MEM_writeLE24(op, cBlockHeader);
|
|
op[3] = src;
|
|
return 4;
|
|
}
|
|
|
|
|
|
/* ZSTD_minGain() :
|
|
* minimum compression required
|
|
* to generate a compress block or a compressed literals section.
|
|
* note : use same formula for both situations */
|
|
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, (int)strat));
|
|
return (srcSize >> minlog) + 2;
|
|
}
|
|
|
|
MEM_STATIC int ZSTD_literalsCompressionIsDisabled(const ZSTD_CCtx_params* cctxParams)
|
|
{
|
|
switch (cctxParams->literalCompressionMode) {
|
|
case ZSTD_ps_enable:
|
|
return 0;
|
|
case ZSTD_ps_disable:
|
|
return 1;
|
|
default:
|
|
assert(0 /* impossible: pre-validated */);
|
|
ZSTD_FALLTHROUGH;
|
|
case ZSTD_ps_auto:
|
|
return (cctxParams->cParams.strategy == ZSTD_fast) && (cctxParams->cParams.targetLength > 0);
|
|
}
|
|
}
|
|
|
|
/*! ZSTD_safecopyLiterals() :
|
|
* memcpy() function that won't read beyond more than WILDCOPY_OVERLENGTH bytes past ilimit_w.
|
|
* 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)
|
|
{
|
|
assert(iend > ilimit_w);
|
|
if (ip <= ilimit_w) {
|
|
ZSTD_wildcopy(op, ip, ilimit_w - ip, ZSTD_no_overlap);
|
|
op += ilimit_w - ip;
|
|
ip = ilimit_w;
|
|
}
|
|
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, 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 offBase,
|
|
size_t matchLength)
|
|
{
|
|
BYTE const* const litLimit_w = litLimit - WILDCOPY_OVERLENGTH;
|
|
BYTE const* const litEnd = literals + litLength;
|
|
#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 offBase%7u",
|
|
pos, (U32)litLength, (U32)matchLength, (U32)offBase);
|
|
}
|
|
#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);
|
|
assert(literals + litLength <= litLimit);
|
|
if (litEnd <= litLimit_w) {
|
|
/* Common case we can use wildcopy.
|
|
* 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);
|
|
}
|
|
} else {
|
|
ZSTD_safecopyLiterals(seqStorePtr->lit, literals, litEnd, litLimit_w);
|
|
}
|
|
seqStorePtr->lit += litLength;
|
|
|
|
/* literal Length */
|
|
if (litLength>0xFFFF) {
|
|
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].offBase = offBase;
|
|
|
|
/* match Length */
|
|
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++;
|
|
}
|
|
|
|
/* 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 (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 */
|
|
}
|
|
}
|
|
}
|
|
|
|
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;
|
|
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) { 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) { 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) { 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) { 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) { 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) { 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 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:
|
|
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
|
|
***************************************/
|
|
#if (ZSTD_WINDOWLOG_MAX_64 > 31)
|
|
# error "ZSTD_WINDOWLOG_MAX is too large : would overflow ZSTD_CURRENT_MAX"
|
|
#endif
|
|
/* 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;
|
|
}
|
|
|
|
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.
|
|
*/
|
|
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 ?
|
|
(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 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;
|
|
}
|
|
|
|
/**
|
|
* 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.
|
|
*/
|
|
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 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 + 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 >= 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;
|
|
}
|
|
|
|
/**
|
|
* ZSTD_window_enforceMaxDist():
|
|
* Updates lowLimit so that:
|
|
* (srcEnd - base) - lowLimit == maxDist + loadedDictEnd
|
|
*
|
|
* It ensures index is valid as long as index >= lowLimit.
|
|
* This must be called before a block compression call.
|
|
*
|
|
* loadedDictEnd is only defined if a dictionary is in use for current compression.
|
|
* As the name implies, loadedDictEnd represents the index at end of dictionary.
|
|
* The value lies within context's referential, it can be directly compared to blockEndIdx.
|
|
*
|
|
* If loadedDictEndPtr is NULL, no dictionary is in use, and we use loadedDictEnd == 0.
|
|
* If loadedDictEndPtr is not NULL, we set it to zero after updating lowLimit.
|
|
* This is because dictionaries are allowed to be referenced fully
|
|
* as long as the last byte of the dictionary is in the window.
|
|
* Once input has progressed beyond window size, dictionary cannot be referenced anymore.
|
|
*
|
|
* In normal dict mode, the dictionary lies 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,
|
|
const void* blockEnd,
|
|
U32 maxDist,
|
|
U32* loadedDictEndPtr,
|
|
const ZSTD_matchState_t** dictMatchStatePtr)
|
|
{
|
|
U32 const blockEndIdx = (U32)((BYTE const*)blockEnd - window->base);
|
|
U32 const loadedDictEnd = (loadedDictEndPtr != NULL) ? *loadedDictEndPtr : 0;
|
|
DEBUGLOG(5, "ZSTD_window_enforceMaxDist: blockEndIdx=%u, maxDist=%u, loadedDictEnd=%u",
|
|
(unsigned)blockEndIdx, (unsigned)maxDist, (unsigned)loadedDictEnd);
|
|
|
|
/* - When there is no dictionary : loadedDictEnd == 0.
|
|
In which case, the test (blockEndIdx > maxDist) is merely to avoid
|
|
overflowing next operation `newLowLimit = blockEndIdx - maxDist`.
|
|
- When there is a standard dictionary :
|
|
Index referential is copied from the dictionary,
|
|
which means it starts from 0.
|
|
In which case, loadedDictEnd == dictSize,
|
|
and it makes sense to compare `blockEndIdx > maxDist + dictSize`
|
|
since `blockEndIdx` also starts from zero.
|
|
- When there is an attached dictionary :
|
|
loadedDictEnd is expressed within the referential of the context,
|
|
so it can be directly compared against blockEndIdx.
|
|
*/
|
|
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;
|
|
}
|
|
/* On reaching window size, dictionaries are invalidated */
|
|
if (loadedDictEndPtr) *loadedDictEndPtr = 0;
|
|
if (dictMatchStatePtr) *dictMatchStatePtr = NULL;
|
|
}
|
|
}
|
|
|
|
/* Similar to ZSTD_window_enforceMaxDist(),
|
|
* but only invalidates dictionary
|
|
* when input progresses beyond window size.
|
|
* assumption : loadedDictEndPtr and dictMatchStatePtr are valid (non NULL)
|
|
* loadedDictEnd uses same referential as window->base
|
|
* maxDist is the window size */
|
|
MEM_STATIC void
|
|
ZSTD_checkDictValidity(const ZSTD_window_t* window,
|
|
const void* blockEnd,
|
|
U32 maxDist,
|
|
U32* loadedDictEndPtr,
|
|
const ZSTD_matchState_t** dictMatchStatePtr)
|
|
{
|
|
assert(loadedDictEndPtr != NULL);
|
|
assert(dictMatchStatePtr != NULL);
|
|
{ U32 const blockEndIdx = (U32)((BYTE const*)blockEnd - window->base);
|
|
U32 const loadedDictEnd = *loadedDictEndPtr;
|
|
DEBUGLOG(5, "ZSTD_checkDictValidity: blockEndIdx=%u, maxDist=%u, loadedDictEnd=%u",
|
|
(unsigned)blockEndIdx, (unsigned)maxDist, (unsigned)loadedDictEnd);
|
|
assert(blockEndIdx >= loadedDictEnd);
|
|
|
|
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;
|
|
*dictMatchStatePtr = NULL;
|
|
} else {
|
|
if (*loadedDictEndPtr != 0) {
|
|
DEBUGLOG(6, "dictionary considered valid for current block");
|
|
} } }
|
|
}
|
|
|
|
MEM_STATIC void ZSTD_window_init(ZSTD_window_t* window) {
|
|
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;
|
|
}
|
|
|
|
/**
|
|
* 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,
|
|
int forceNonContiguous)
|
|
{
|
|
BYTE const* const ip = (BYTE const*)src;
|
|
U32 contiguous = 1;
|
|
DEBUGLOG(5, "ZSTD_window_update");
|
|
if (srcSize == 0)
|
|
return contiguous;
|
|
assert(window->base != NULL);
|
|
assert(window->dictBase != NULL);
|
|
/* Check if blocks follow each other */
|
|
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);
|
|
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;
|
|
}
|
|
|
|
/**
|
|
* 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 curr, unsigned windowLog)
|
|
{
|
|
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 curr, unsigned windowLog)
|
|
{
|
|
U32 const maxDistance = 1U << windowLog;
|
|
U32 const lowestValid = ms->window.dictLimit;
|
|
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;
|
|
}
|
|
|
|
|
|
|
|
/* 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
|
|
|
|
/* 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)
|
|
}
|
|
#endif
|
|
|
|
/* ===============================================================
|
|
* Shared internal declarations
|
|
* These prototypes may be called from sources not in lib/compress
|
|
* =============================================================== */
|
|
|
|
/* ZSTD_loadCEntropy() :
|
|
* dict : must point at beginning of a valid zstd dictionary.
|
|
* return : size of dictionary header (size of magic number + dict ID + entropy tables)
|
|
* assumptions : magic number supposed already checked
|
|
* and dictSize >= 8 */
|
|
size_t ZSTD_loadCEntropy(ZSTD_compressedBlockState_t* bs, void* workspace,
|
|
const void* const dict, size_t dictSize);
|
|
|
|
void ZSTD_reset_compressedBlockState(ZSTD_compressedBlockState_t* bs);
|
|
|
|
/* ==============================================================
|
|
* 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.
|
|
* Note: srcSizeHint == 0 means 0!
|
|
*/
|
|
ZSTD_compressionParameters ZSTD_getCParamsFromCCtxParams(
|
|
const ZSTD_CCtx_params* CCtxParams, U64 srcSizeHint, size_t dictSize, ZSTD_cParamMode_e mode);
|
|
|
|
/*! 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,
|
|
const 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,
|
|
const 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,
|
|
const 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);
|
|
|
|
/** ZSTD_cycleLog() :
|
|
* 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 */
|