mirror
/
tracy
mirror of https://github.com/wolfpld/tracy.git
Code Releases Wiki Activity
You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
master
wayland-refactor
v0.1
v0.10
v0.11.0
v0.11.1
v0.2
v0.3.3
v0.4
v0.4.1
v0.5
v0.6
v0.6.1
v0.6.2
v0.6.3
v0.7
v0.7.1
v0.7.2
v0.7.3
v0.7.4
v0.7.5
v0.7.6
v0.7.7
v0.7.8
v0.8
v0.8.1
v0.8.2
v0.8.2.1
v0.9
v0.9.1
Branches Tags
${ item.name }
Create tag ${ searchTerm }
Create branch ${ searchTerm }
from 'master'
${ noResults }
tracy/zstd/compress/zstd_compress_internal.h

1535 lines
63 KiB
C
Raw Permalink Blame History

/*
* Copyright (c) Meta Platforms, Inc. and affiliates.
* 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 "../common/zstd_internal.h"
#include "zstd_cwksp.h"
#ifdef ZSTD_MULTITHREAD
# include "zstdmt_compress.h"
#endif
#include "../common/bits.h" /* ZSTD_highbit32, ZSTD_NbCommonBytes */
#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 ZSTD_DUBT_UNSORTED_MARK==1 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 reuse with a different strategy.
This constant is 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 {
HUF_CElt CTable[HUF_CTABLE_SIZE_ST(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;
/***********************************************
* Entropy buffer statistics structs and funcs *
***********************************************/
/** ZSTD_hufCTablesMetadata_t :
* Stores Literals Block Type for a super-block in hType, and
* huffman tree description in hufDesBuffer.
* hufDesSize refers to the size of huffman tree description in bytes.
* This metadata is populated in ZSTD_buildBlockEntropyStats_literals() */
typedef struct {
symbolEncodingType_e hType;
BYTE hufDesBuffer[ZSTD_MAX_HUF_HEADER_SIZE];
size_t hufDesSize;
} ZSTD_hufCTablesMetadata_t;
/** ZSTD_fseCTablesMetadata_t :
* Stores symbol compression modes for a super-block in {ll, ol, ml}Type, and
* fse tables in fseTablesBuffer.
* fseTablesSize refers to the size of fse tables in bytes.
* This metadata is populated in ZSTD_buildBlockEntropyStats_sequences() */
typedef struct {
symbolEncodingType_e llType;
symbolEncodingType_e ofType;
symbolEncodingType_e mlType;
BYTE fseTablesBuffer[ZSTD_MAX_FSE_HEADERS_SIZE];
size_t fseTablesSize;
size_t lastCountSize; /* This is to account for bug in 1.3.4. More detail in ZSTD_entropyCompressSeqStore_internal() */
} ZSTD_fseCTablesMetadata_t;
typedef struct {
ZSTD_hufCTablesMetadata_t hufMetadata;
ZSTD_fseCTablesMetadata_t fseMetadata;
} ZSTD_entropyCTablesMetadata_t;
/** ZSTD_buildBlockEntropyStats() :
* Builds entropy for the block.
* @return : 0 on success or error code */
size_t ZSTD_buildBlockEntropyStats(
const seqStore_t* seqStorePtr,
const ZSTD_entropyCTables_t* prevEntropy,
ZSTD_entropyCTables_t* nextEntropy,
const ZSTD_CCtx_params* cctxParams,
ZSTD_entropyCTablesMetadata_t* entropyMetadata,
void* workspace, size_t wkspSize);
/*********************************
* Compression internals structs *
*********************************/
typedef struct {
U32 off; /* Offset sumtype code for the match, using ZSTD_storeSeq() format */
U32 len; /* Raw length of match */
} ZSTD_match_t;
typedef struct {
U32 offset; /* Offset of sequence */
U32 litLength; /* Length of literals prior to match */
U32 matchLength; /* Raw length of match */
} rawSeq;
typedef struct {
rawSeq* seq; /* The start of the sequences */
size_t pos; /* The index in seq where reading stopped. pos <= size. */
size_t posInSequence; /* The position within the sequence at seq[pos] where reading
stopped. posInSequence <= seq[pos].litLength + seq[pos].matchLength */
size_t size; /* The number of sequences. <= capacity. */
size_t capacity; /* The capacity starting from `seq` pointer */
} rawSeqStore_t;
typedef struct {
U32 idx; /* Index in array of ZSTD_Sequence */
U32 posInSequence; /* Position within sequence at idx */
size_t posInSrc; /* Number of bytes given by sequences provided so far */
} ZSTD_sequencePosition;
UNUSED_ATTR static const rawSeqStore_t kNullRawSeqStore = {NULL, 0, 0, 0, 0};
typedef struct {
int price; /* price from beginning of segment to this position */
U32 off; /* offset of previous match */
U32 mlen; /* length of previous match */
U32 litlen; /* nb of literals since previous match */
U32 rep[ZSTD_REP_NUM]; /* offset history after previous match */
} ZSTD_optimal_t;
typedef enum { zop_dynamic=0, zop_predef } ZSTD_OptPrice_e;
#define ZSTD_OPT_SIZE (ZSTD_OPT_NUM+3)
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_SIZE */
ZSTD_optimal_t* priceTable; /* All positions tracked by optimal parser, of size ZSTD_OPT_SIZE */
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_paramSwitch_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 valid data */
U32 nbOverflowCorrections; /* Number of times overflow correction has run since
* ZSTD_window_init(). Useful for debugging coredumps
* and for ZSTD_WINDOW_OVERFLOW_CORRECT_FREQUENTLY.
*/
} ZSTD_window_t;
#define ZSTD_WINDOW_START_INDEX 2
typedef struct ZSTD_matchState_t ZSTD_matchState_t;
#define ZSTD_ROW_HASH_CACHE_SIZE 8 /* Size of prefetching hash cache for row-based matchfinder */
struct ZSTD_matchState_t {
ZSTD_window_t window; /* State for window round buffer management */
U32 loadedDictEnd; /* index of end of dictionary, within context's referential.
* When loadedDictEnd != 0, a dictionary is in use, and still valid.
* This relies on a mechanism to set loadedDictEnd=0 when dictionary is no longer within distance.
* Such mechanism is provided within ZSTD_window_enforceMaxDist() and ZSTD_checkDictValidity().
* When dict referential is copied into active context (i.e. not attached),
* loadedDictEnd == dictSize, since referential starts from zero.
*/
U32 nextToUpdate; /* index from which to continue table update */
U32 hashLog3; /* dispatch table for matches of len==3 : larger == faster, more memory */
U32 rowHashLog; /* For row-based matchfinder: Hashlog based on nb of rows in the hashTable.*/
BYTE* tagTable; /* For row-based matchFinder: A row-based table containing the hashes and head index. */
U32 hashCache[ZSTD_ROW_HASH_CACHE_SIZE]; /* For row-based matchFinder: a cache of hashes to improve speed */
U64 hashSalt; /* For row-based matchFinder: salts the hash for reuse of tag table */
U32 hashSaltEntropy; /* For row-based matchFinder: collects entropy for salt generation */
U32* hashTable;
U32* hashTable3;
U32* chainTable;
U32 forceNonContiguous; /* Non-zero if we should force non-contiguous load for the next window update. */
int dedicatedDictSearch; /* Indicates whether this matchState is using the
* dedicated dictionary search structure.
*/
optState_t opt; /* optimal parser state */
const ZSTD_matchState_t* dictMatchState;
ZSTD_compressionParameters cParams;
const rawSeqStore_t* ldmSeqStore;
/* Controls prefetching in some dictMatchState matchfinders.
* This behavior is controlled from the cctx ms.
* This parameter has no effect in the cdict ms. */
int prefetchCDictTables;
/* When == 0, lazy match finders insert every position.
* When != 0, lazy match finders only insert positions they search.
* This allows them to skip much faster over incompressible data,
* at a small cost to compression ratio.
*/
int lazySkipping;
};
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 {
BYTE const* split;
U32 hash;
U32 checksum;
ldmEntry_t* bucket;
} ldmMatchCandidate_t;
#define LDM_BATCH_SIZE 64
typedef struct {
ZSTD_window_t window; /* State for the window round buffer management */
ldmEntry_t* hashTable;
U32 loadedDictEnd;
BYTE* bucketOffsets; /* Next position in bucket to insert entry */
size_t splitIndices[LDM_BATCH_SIZE];
ldmMatchCandidate_t matchCandidates[LDM_BATCH_SIZE];
} ldmState_t;
typedef struct {
ZSTD_paramSwitch_e enableLdm; /* ZSTD_ps_enable to enable LDM. ZSTD_ps_auto by default */
U32 hashLog; /* Log size of hashTable */
U32 bucketSizeLog; /* Log bucket size for collision resolution, at most 8 */
U32 minMatchLength; /* Minimum match length */
U32 hashRateLog; /* Log number of entries to skip */
U32 windowLog; /* Window log for the LDM */
} ldmParams_t;
typedef struct {
int collectSequences;
ZSTD_Sequence* seqStart;
size_t seqIndex;
size_t maxSequences;
} SeqCollector;
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 */
size_t targetCBlockSize; /* Tries to fit compressed block size to be around targetCBlockSize.
* No target when targetCBlockSize == 0.
* There is no guarantee on compressed block size */
int srcSizeHint; /* User's best guess of source size.
* Hint is not valid when srcSizeHint == 0.
* There is no guarantee that hint is close to actual source size */
ZSTD_dictAttachPref_e attachDictPref;
ZSTD_paramSwitch_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;
/* Dedicated dict search algorithm trigger */
int enableDedicatedDictSearch;
/* Input/output buffer modes */
ZSTD_bufferMode_e inBufferMode;
ZSTD_bufferMode_e outBufferMode;
/* Sequence compression API */
ZSTD_sequenceFormat_e blockDelimiters;
int validateSequences;
/* Block splitting */
ZSTD_paramSwitch_e useBlockSplitter;
/* Param for deciding whether to use row-based matchfinder */
ZSTD_paramSwitch_e useRowMatchFinder;
/* Always load a dictionary in ext-dict mode (not prefix mode)? */
int deterministicRefPrefix;
/* Internal use, for createCCtxParams() and freeCCtxParams() only */
ZSTD_customMem customMem;
/* Controls prefetching in some dictMatchState matchfinders */
ZSTD_paramSwitch_e prefetchCDictTables;
/* Controls whether zstd will fall back to an internal matchfinder
* if the external matchfinder returns an error code. */
int enableMatchFinderFallback;
/* Parameters for the external sequence producer API.
* Users set these parameters through ZSTD_registerSequenceProducer().
* It is not possible to set these parameters individually through the public API. */
void* extSeqProdState;
ZSTD_sequenceProducer_F extSeqProdFunc;
/* Adjust the max block size*/
size_t maxBlockSize;
/* Controls repcode search in external sequence parsing */
ZSTD_paramSwitch_e searchForExternalRepcodes;
}; /* typedef'd to ZSTD_CCtx_params within "zstd.h" */
#define COMPRESS_SEQUENCES_WORKSPACE_SIZE (sizeof(unsigned) * (MaxSeq + 2))
#define ENTROPY_WORKSPACE_SIZE (HUF_WORKSPACE_SIZE + COMPRESS_SEQUENCES_WORKSPACE_SIZE)
/**
* Indicates whether this compression proceeds directly from user-provided
* source buffer to user-provided destination buffer (ZSTDb_not_buffered), or
* whether the context needs to buffer the input/output (ZSTDb_buffered).
*/
typedef enum {
ZSTDb_not_buffered,
ZSTDb_buffered
} ZSTD_buffered_policy_e;
/**
* Struct that contains all elements of block splitter that should be allocated
* in a wksp.
*/
#define ZSTD_MAX_NB_BLOCK_SPLITS 196
typedef struct {
seqStore_t fullSeqStoreChunk;
seqStore_t firstHalfSeqStore;
seqStore_t secondHalfSeqStore;
seqStore_t currSeqStore;
seqStore_t nextSeqStore;
U32 partitions[ZSTD_MAX_NB_BLOCK_SPLITS];
ZSTD_entropyCTablesMetadata_t entropyMetadata;
} ZSTD_blockSplitCtx;
struct ZSTD_CCtx_s {
ZSTD_compressionStage_e stage;
int cParamsChanged; /* == 1 if cParams(except wlog) or compression level are changed in requestedParams. Triggers transmission of new params to ZSTDMT (if available) then reset to 0. */
int bmi2; /* == 1 if the CPU supports BMI2 and 0 otherwise. CPU support is determined dynamically once per context lifetime. */
ZSTD_CCtx_params requestedParams;
ZSTD_CCtx_params appliedParams;
ZSTD_CCtx_params simpleApiParams; /* Param storage used by the simple API - not sticky. Must only be used in top-level simple API functions for storage. */
U32 dictID;
size_t dictContentSize;
ZSTD_cwksp workspace; /* manages buffer for dynamic allocations */
size_t blockSize;
unsigned long long pledgedSrcSizePlusOne; /* this way, 0 (default) == unknown */
unsigned long long consumedSrcSize;
unsigned long long producedCSize;
XXH64_state_t xxhState;
ZSTD_customMem customMem;
ZSTD_threadPool* pool;
size_t staticSize;
SeqCollector seqCollector;
int isFirstBlock;
int initialized;
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 ENTROPY_WORKSPACE_SIZE bytes */
/* Whether we are streaming or not */
ZSTD_buffered_policy_e bufferedPolicy;
/* 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;
/* Stable in/out buffer verification */
ZSTD_inBuffer expectedInBuffer;
size_t stableIn_notConsumed; /* nb bytes within stable input buffer that are said to be consumed but are not */
size_t expectedOutBufferSize;
/* Dictionary */
ZSTD_localDict localDict;
const ZSTD_CDict* cdict;
ZSTD_prefixDict prefixDict; /* single-usage dictionary */
/* Multi-threading */
#ifdef ZSTD_MULTITHREAD
ZSTDMT_CCtx* mtctx;
#endif
/* Tracing */
#if ZSTD_TRACE
ZSTD_TraceCtx traceCtx;
#endif
/* Workspace for block splitter */
ZSTD_blockSplitCtx blockSplitCtx;
/* Buffer for output from external sequence producer */
ZSTD_Sequence* extSeqBuf;
size_t extSeqBufCapacity;
};
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, U32 s) { assert(h <= 32); return (((u << (32-24)) * prime3bytes) ^ s) >> (32-h) ; }
MEM_STATIC size_t ZSTD_hash3Ptr(const void* ptr, U32 h) { return ZSTD_hash3(MEM_readLE32(ptr), h, 0); } /* only in zstd_opt.h */
MEM_STATIC size_t ZSTD_hash3PtrS(const void* ptr, U32 h, U32 s) { return ZSTD_hash3(MEM_readLE32(ptr), h, s); }
static const U32 prime4bytes = 2654435761U;
static U32 ZSTD_hash4(U32 u, U32 h, U32 s) { assert(h <= 32); return ((u * prime4bytes) ^ s) >> (32-h) ; }
static size_t ZSTD_hash4Ptr(const void* ptr, U32 h) { return ZSTD_hash4(MEM_readLE32(ptr), h, 0); }
static size_t ZSTD_hash4PtrS(const void* ptr, U32 h, U32 s) { return ZSTD_hash4(MEM_readLE32(ptr), h, s); }
static const U64 prime5bytes = 889523592379ULL;
static size_t ZSTD_hash5(U64 u, U32 h, U64 s) { assert(h <= 64); return (size_t)((((u << (64-40)) * prime5bytes) ^ s) >> (64-h)) ; }
static size_t ZSTD_hash5Ptr(const void* p, U32 h) { return ZSTD_hash5(MEM_readLE64(p), h, 0); }
static size_t ZSTD_hash5PtrS(const void* p, U32 h, U64 s) { return ZSTD_hash5(MEM_readLE64(p), h, s); }
static const U64 prime6bytes = 227718039650203ULL;
static size_t ZSTD_hash6(U64 u, U32 h, U64 s) { assert(h <= 64); return (size_t)((((u << (64-48)) * prime6bytes) ^ s) >> (64-h)) ; }
static size_t ZSTD_hash6Ptr(const void* p, U32 h) { return ZSTD_hash6(MEM_readLE64(p), h, 0); }
static size_t ZSTD_hash6PtrS(const void* p, U32 h, U64 s) { return ZSTD_hash6(MEM_readLE64(p), h, s); }
static const U64 prime7bytes = 58295818150454627ULL;
static size_t ZSTD_hash7(U64 u, U32 h, U64 s) { assert(h <= 64); return (size_t)((((u << (64-56)) * prime7bytes) ^ s) >> (64-h)) ; }
static size_t ZSTD_hash7Ptr(const void* p, U32 h) { return ZSTD_hash7(MEM_readLE64(p), h, 0); }
static size_t ZSTD_hash7PtrS(const void* p, U32 h, U64 s) { return ZSTD_hash7(MEM_readLE64(p), h, s); }
static const U64 prime8bytes = 0xCF1BBCDCB7A56463ULL;
static size_t ZSTD_hash8(U64 u, U32 h, U64 s) { assert(h <= 64); return (size_t)((((u) * prime8bytes) ^ s) >> (64-h)) ; }
static size_t ZSTD_hash8Ptr(const void* p, U32 h) { return ZSTD_hash8(MEM_readLE64(p), h, 0); }
static size_t ZSTD_hash8PtrS(const void* p, U32 h, U64 s) { return ZSTD_hash8(MEM_readLE64(p), h, s); }
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);
}
}
MEM_STATIC FORCE_INLINE_ATTR
size_t ZSTD_hashPtrSalted(const void* p, U32 hBits, U32 mls, const U64 hashSalt) {
/* 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_hash4PtrS(p, hBits, (U32)hashSalt);
case 5: return ZSTD_hash5PtrS(p, hBits, hashSalt);
case 6: return ZSTD_hash6PtrS(p, hBits, hashSalt);
case 7: return ZSTD_hash7PtrS(p, hBits, hashSalt);
case 8: return ZSTD_hash8PtrS(p, hBits, hashSalt);
}
}
/** 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
ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
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
ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
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.
* NOTE: seqs are not verified! Invalid sequences can cause out-of-bounds memory
* access and data corruption.
*/
void 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);
/* Returns 1 if an external sequence producer is registered, otherwise returns 0. */
MEM_STATIC int ZSTD_hasExtSeqProd(const ZSTD_CCtx_params* params) {
return params->extSeqProdFunc != NULL;
}
/* ===============================================================
* Deprecated definitions that are still used internally to avoid
* deprecation warnings. These functions are exactly equivalent to
* their public variants, but avoid the deprecation warnings.
* =============================================================== */
size_t ZSTD_compressBegin_usingCDict_deprecated(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict);
size_t ZSTD_compressContinue_public(ZSTD_CCtx* cctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize);
size_t ZSTD_compressEnd_public(ZSTD_CCtx* cctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize);
size_t ZSTD_compressBlock_deprecated(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
#endif /* ZSTD_COMPRESS_H */
View Git Blame Copy Permalink