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Rename "External Matchfinder" to "Block-Level Sequence Producer" (#3484)

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* change "external matchfinder" to "external sequence producer"

* migrate contrib/ to new naming convention

* fix contrib build

* fix error message

* update debug strings

* fix def of invalid sequences in zstd.h

* nit

* update CHANGELOG

* fix .gitignore
This commit is contained in:
Elliot Gorokhovsky
2023-02-09 17:01:17 -05:00
committed by GitHub
parent 4aa3bc49da
commit ff42ed1582
20 changed files with 231 additions and 220 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/common/error_private.c
+1 -1
View File
@@ -54,7 +54,7 @@ const char* ERR_getErrorString(ERR_enum code)
case PREFIX(seekableIO): return "An I/O error occurred when reading/seeking";
case PREFIX(dstBuffer_wrong): return "Destination buffer is wrong";
case PREFIX(srcBuffer_wrong): return "Source buffer is wrong";
case PREFIX(externalMatchFinder_failed): return "External matchfinder returned an error code";
case PREFIX(sequenceProducer_failed): return "Block-level external sequence producer returned an error code";
case PREFIX(externalSequences_invalid): return "External sequences are not valid";
case PREFIX(maxCode):
default: return notErrorCode;
lib/compress/zstd_compress.c
+41 -41
View File
@@ -615,7 +615,7 @@ ZSTD_bounds ZSTD_cParam_getBounds(ZSTD_cParameter param)
bounds.upperBound = (int)ZSTD_ps_disable;
return bounds;
case ZSTD_c_enableMatchFinderFallback:
case ZSTD_c_enableSeqProducerFallback:
bounds.lowerBound = 0;
bounds.upperBound = 1;
return bounds;
@@ -695,7 +695,7 @@ static int ZSTD_isUpdateAuthorized(ZSTD_cParameter param)
case ZSTD_c_useRowMatchFinder:
case ZSTD_c_deterministicRefPrefix:
case ZSTD_c_prefetchCDictTables:
case ZSTD_c_enableMatchFinderFallback:
case ZSTD_c_enableSeqProducerFallback:
case ZSTD_c_maxBlockSize:
case ZSTD_c_searchForExternalRepcodes:
default:
@@ -754,7 +754,7 @@ size_t ZSTD_CCtx_setParameter(ZSTD_CCtx* cctx, ZSTD_cParameter param, int value)
case ZSTD_c_useRowMatchFinder:
case ZSTD_c_deterministicRefPrefix:
case ZSTD_c_prefetchCDictTables:
case ZSTD_c_enableMatchFinderFallback:
case ZSTD_c_enableSeqProducerFallback:
case ZSTD_c_maxBlockSize:
case ZSTD_c_searchForExternalRepcodes:
break;
@@ -989,8 +989,8 @@ size_t ZSTD_CCtxParams_setParameter(ZSTD_CCtx_params* CCtxParams,
CCtxParams->prefetchCDictTables = (ZSTD_paramSwitch_e)value;
return CCtxParams->prefetchCDictTables;
case ZSTD_c_enableMatchFinderFallback:
BOUNDCHECK(ZSTD_c_enableMatchFinderFallback, value);
case ZSTD_c_enableSeqProducerFallback:
BOUNDCHECK(ZSTD_c_enableSeqProducerFallback, value);
CCtxParams->enableMatchFinderFallback = value;
return CCtxParams->enableMatchFinderFallback;
@@ -1140,7 +1140,7 @@ size_t ZSTD_CCtxParams_getParameter(
case ZSTD_c_prefetchCDictTables:
*value = (int)CCtxParams->prefetchCDictTables;
break;
case ZSTD_c_enableMatchFinderFallback:
case ZSTD_c_enableSeqProducerFallback:
*value = CCtxParams->enableMatchFinderFallback;
break;
case ZSTD_c_maxBlockSize:
@@ -1610,8 +1610,8 @@ ZSTD_sizeof_matchState(const ZSTD_compressionParameters* const cParams,
/* Helper function for calculating memory requirements.
* Gives a tighter bound than ZSTD_sequenceBound() by taking minMatch into account. */
static size_t ZSTD_maxNbSeq(size_t blockSize, unsigned minMatch, int useExternalMatchFinder) {
U32 const divider = (minMatch==3 || useExternalMatchFinder) ? 3 : 4;
static size_t ZSTD_maxNbSeq(size_t blockSize, unsigned minMatch, int useSequenceProducer) {
U32 const divider = (minMatch==3 || useSequenceProducer) ? 3 : 4;
return blockSize / divider;
}
@@ -1623,12 +1623,12 @@ static size_t ZSTD_estimateCCtxSize_usingCCtxParams_internal(
const size_t buffInSize,
const size_t buffOutSize,
const U64 pledgedSrcSize,
int useExternalMatchFinder,
int useSequenceProducer,
size_t maxBlockSize)
{
size_t const windowSize = (size_t) BOUNDED(1ULL, 1ULL << cParams->windowLog, pledgedSrcSize);
size_t const blockSize = MIN(ZSTD_resolveMaxBlockSize(maxBlockSize), windowSize);
size_t const maxNbSeq = ZSTD_maxNbSeq(blockSize, cParams->minMatch, useExternalMatchFinder);
size_t const maxNbSeq = ZSTD_maxNbSeq(blockSize, cParams->minMatch, useSequenceProducer);
size_t const tokenSpace = ZSTD_cwksp_alloc_size(WILDCOPY_OVERLENGTH + blockSize)
+ ZSTD_cwksp_aligned_alloc_size(maxNbSeq * sizeof(seqDef))
+ 3 * ZSTD_cwksp_alloc_size(maxNbSeq * sizeof(BYTE));
@@ -1648,7 +1648,7 @@ static size_t ZSTD_estimateCCtxSize_usingCCtxParams_internal(
size_t const cctxSpace = isStatic ? ZSTD_cwksp_alloc_size(sizeof(ZSTD_CCtx)) : 0;
size_t const maxNbExternalSeq = ZSTD_sequenceBound(blockSize);
size_t const externalSeqSpace = useExternalMatchFinder
size_t const externalSeqSpace = useSequenceProducer
? ZSTD_cwksp_aligned_alloc_size(maxNbExternalSeq * sizeof(ZSTD_Sequence))
: 0;
@@ -1679,7 +1679,7 @@ size_t ZSTD_estimateCCtxSize_usingCCtxParams(const ZSTD_CCtx_params* params)
* be needed. However, we still allocate two 0-sized buffers, which can
* take space under ASAN. */
return ZSTD_estimateCCtxSize_usingCCtxParams_internal(
&cParams, &params->ldmParams, 1, useRowMatchFinder, 0, 0, ZSTD_CONTENTSIZE_UNKNOWN, params->useExternalMatchFinder, params->maxBlockSize);
&cParams, &params->ldmParams, 1, useRowMatchFinder, 0, 0, ZSTD_CONTENTSIZE_UNKNOWN, params->useSequenceProducer, params->maxBlockSize);
}
size_t ZSTD_estimateCCtxSize_usingCParams(ZSTD_compressionParameters cParams)
@@ -1740,7 +1740,7 @@ size_t ZSTD_estimateCStreamSize_usingCCtxParams(const ZSTD_CCtx_params* params)
return ZSTD_estimateCCtxSize_usingCCtxParams_internal(
&cParams, &params->ldmParams, 1, useRowMatchFinder, inBuffSize, outBuffSize,
ZSTD_CONTENTSIZE_UNKNOWN, params->useExternalMatchFinder, params->maxBlockSize);
ZSTD_CONTENTSIZE_UNKNOWN, params->useSequenceProducer, params->maxBlockSize);
}
}
@@ -2024,7 +2024,7 @@ static size_t ZSTD_resetCCtx_internal(ZSTD_CCtx* zc,
{ size_t const windowSize = MAX(1, (size_t)MIN(((U64)1 << params->cParams.windowLog), pledgedSrcSize));
size_t const blockSize = MIN(params->maxBlockSize, windowSize);
size_t const maxNbSeq = ZSTD_maxNbSeq(blockSize, params->cParams.minMatch, params->useExternalMatchFinder);
size_t const maxNbSeq = ZSTD_maxNbSeq(blockSize, params->cParams.minMatch, params->useSequenceProducer);
size_t const buffOutSize = (zbuff == ZSTDb_buffered && params->outBufferMode == ZSTD_bm_buffered)
? ZSTD_compressBound(blockSize) + 1
: 0;
@@ -2041,7 +2041,7 @@ static size_t ZSTD_resetCCtx_internal(ZSTD_CCtx* zc,
size_t const neededSpace =
ZSTD_estimateCCtxSize_usingCCtxParams_internal(
&params->cParams, &params->ldmParams, zc->staticSize != 0, params->useRowMatchFinder,
buffInSize, buffOutSize, pledgedSrcSize, params->useExternalMatchFinder, params->maxBlockSize);
buffInSize, buffOutSize, pledgedSrcSize, params->useSequenceProducer, params->maxBlockSize);
int resizeWorkspace;
FORWARD_IF_ERROR(neededSpace, "cctx size estimate failed!");
@@ -2155,7 +2155,7 @@ static size_t ZSTD_resetCCtx_internal(ZSTD_CCtx* zc,
}
/* reserve space for block-level external sequences */
if (params->useExternalMatchFinder) {
if (params->useSequenceProducer) {
size_t const maxNbExternalSeq = ZSTD_sequenceBound(blockSize);
zc->externalMatchCtx.seqBufferCapacity = maxNbExternalSeq;
zc->externalMatchCtx.seqBuffer =
@@ -3022,26 +3022,26 @@ void ZSTD_resetSeqStore(seqStore_t* ssPtr)
ssPtr->longLengthType = ZSTD_llt_none;
}
/* ZSTD_postProcessExternalMatchFinderResult() :
/* ZSTD_postProcessSequenceProducerResult() :
* Validates and post-processes sequences obtained through the external matchfinder API:
* - Checks whether nbExternalSeqs represents an error condition.
* - Appends a block delimiter to outSeqs if one is not already present.
* See zstd.h for context regarding block delimiters.
* Returns the number of sequences after post-processing, or an error code. */
static size_t ZSTD_postProcessExternalMatchFinderResult(
static size_t ZSTD_postProcessSequenceProducerResult(
ZSTD_Sequence* outSeqs, size_t nbExternalSeqs, size_t outSeqsCapacity, size_t srcSize
) {
RETURN_ERROR_IF(
nbExternalSeqs > outSeqsCapacity,
externalMatchFinder_failed,
"External matchfinder returned error code %lu",
sequenceProducer_failed,
"External sequence producer returned error code %lu",
(unsigned long)nbExternalSeqs
);
RETURN_ERROR_IF(
nbExternalSeqs == 0 && srcSize > 0,
externalMatchFinder_failed,
"External matchfinder produced zero sequences for a non-empty src buffer!"
sequenceProducer_failed,
"Got zero sequences from external sequence producer for a non-empty src buffer!"
);
if (srcSize == 0) {
@@ -3061,7 +3061,7 @@ static size_t ZSTD_postProcessExternalMatchFinderResult(
* produced an invalid parse, by definition of ZSTD_sequenceBound(). */
RETURN_ERROR_IF(
nbExternalSeqs == outSeqsCapacity,
externalMatchFinder_failed,
sequenceProducer_failed,
"nbExternalSeqs == outSeqsCapacity but lastSeq is not a block delimiter!"
);
@@ -3139,9 +3139,9 @@ static size_t ZSTD_buildSeqStore(ZSTD_CCtx* zc, const void* src, size_t srcSize)
/* External matchfinder + LDM is technically possible, just not implemented yet.
* We need to revisit soon and implement it. */
RETURN_ERROR_IF(
zc->appliedParams.useExternalMatchFinder,
zc->appliedParams.useSequenceProducer,
parameter_combination_unsupported,
"Long-distance matching with external matchfinder enabled is not currently supported."
"Long-distance matching with external sequence producer enabled is not currently supported."
);
/* Updates ldmSeqStore.pos */
@@ -3158,9 +3158,9 @@ static size_t ZSTD_buildSeqStore(ZSTD_CCtx* zc, const void* src, size_t srcSize)
/* External matchfinder + LDM is technically possible, just not implemented yet.
* We need to revisit soon and implement it. */
RETURN_ERROR_IF(
zc->appliedParams.useExternalMatchFinder,
zc->appliedParams.useSequenceProducer,
parameter_combination_unsupported,
"Long-distance matching with external matchfinder enabled is not currently supported."
"Long-distance matching with external sequence producer enabled is not currently supported."
);
ldmSeqStore.seq = zc->ldmSequences;
@@ -3177,7 +3177,7 @@ static size_t ZSTD_buildSeqStore(ZSTD_CCtx* zc, const void* src, size_t srcSize)
zc->appliedParams.useRowMatchFinder,
src, srcSize);
assert(ldmSeqStore.pos == ldmSeqStore.size);
} else if (zc->appliedParams.useExternalMatchFinder) {
} else if (zc->appliedParams.useSequenceProducer) {
assert(
zc->externalMatchCtx.seqBufferCapacity >= ZSTD_sequenceBound(srcSize)
);
@@ -3195,7 +3195,7 @@ static size_t ZSTD_buildSeqStore(ZSTD_CCtx* zc, const void* src, size_t srcSize)
windowSize
);
size_t const nbPostProcessedSeqs = ZSTD_postProcessExternalMatchFinderResult(
size_t const nbPostProcessedSeqs = ZSTD_postProcessSequenceProducerResult(
zc->externalMatchCtx.seqBuffer,
nbExternalSeqs,
zc->externalMatchCtx.seqBufferCapacity,
@@ -3217,7 +3217,7 @@ static size_t ZSTD_buildSeqStore(ZSTD_CCtx* zc, const void* src, size_t srcSize)
"Failed to copy external sequences to seqStore!"
);
ms->ldmSeqStore = NULL;
DEBUGLOG(5, "Copied %lu sequences from external matchfinder to internal seqStore.", (unsigned long)nbExternalSeqs);
DEBUGLOG(5, "Copied %lu sequences from external sequence producer to internal seqStore.", (unsigned long)nbExternalSeqs);
return ZSTDbss_compress;
}
@@ -3233,7 +3233,7 @@ static size_t ZSTD_buildSeqStore(ZSTD_CCtx* zc, const void* src, size_t srcSize)
ms->ldmSeqStore = NULL;
DEBUGLOG(
5,
"External matchfinder returned error code %lu. Falling back to internal matchfinder.",
"External sequence producer returned error code %lu. Falling back to internal parser.",
(unsigned long)nbExternalSeqs
);
lastLLSize = blockCompressor(ms, &zc->seqStore, zc->blockState.nextCBlock->rep, src, srcSize);
@@ -6033,9 +6033,9 @@ static size_t ZSTD_CCtx_init_compressStream2(ZSTD_CCtx* cctx,
#ifdef ZSTD_MULTITHREAD
/* If external matchfinder is enabled, make sure to fail before checking job size (for consistency) */
RETURN_ERROR_IF(
params.useExternalMatchFinder == 1 && params.nbWorkers >= 1,
params.useSequenceProducer == 1 && params.nbWorkers >= 1,
parameter_combination_unsupported,
"External matchfinder isn't supported with nbWorkers >= 1"
"External sequence producer isn't supported with nbWorkers >= 1"
);
if ((cctx->pledgedSrcSizePlusOne-1) <= ZSTDMT_JOBSIZE_MIN) {
@@ -6251,7 +6251,7 @@ size_t ZSTD_compress2(ZSTD_CCtx* cctx,
*/
static size_t
ZSTD_validateSequence(U32 offCode, U32 matchLength, U32 minMatch,
size_t posInSrc, U32 windowLog, size_t dictSize, int useExternalMatchFinder)
size_t posInSrc, U32 windowLog, size_t dictSize, int useSequenceProducer)
{
U32 const windowSize = 1u << windowLog;
/* posInSrc represents the amount of data the decoder would decode up to this point.
@@ -6260,7 +6260,7 @@ ZSTD_validateSequence(U32 offCode, U32 matchLength, U32 minMatch,
* window size. After output surpasses windowSize, we're limited to windowSize offsets again.
*/
size_t const offsetBound = posInSrc > windowSize ? (size_t)windowSize : posInSrc + (size_t)dictSize;
size_t const matchLenLowerBound = (minMatch == 3 || useExternalMatchFinder) ? 3 : 4;
size_t const matchLenLowerBound = (minMatch == 3 || useSequenceProducer) ? 3 : 4;
RETURN_ERROR_IF(offCode > OFFSET_TO_OFFBASE(offsetBound), externalSequences_invalid, "Offset too large!");
/* Validate maxNbSeq is large enough for the given matchLength and minMatch */
RETURN_ERROR_IF(matchLength < matchLenLowerBound, externalSequences_invalid, "Matchlength too small for the minMatch");
@@ -6325,7 +6325,7 @@ ZSTD_copySequencesToSeqStoreExplicitBlockDelim(ZSTD_CCtx* cctx,
if (cctx->appliedParams.validateSequences) {
seqPos->posInSrc += litLength + matchLength;
FORWARD_IF_ERROR(ZSTD_validateSequence(offBase, matchLength, cctx->appliedParams.cParams.minMatch, seqPos->posInSrc,
cctx->appliedParams.cParams.windowLog, dictSize, cctx->appliedParams.useExternalMatchFinder),
cctx->appliedParams.cParams.windowLog, dictSize, cctx->appliedParams.useSequenceProducer),
"Sequence validation failed");
}
RETURN_ERROR_IF(idx - seqPos->idx >= cctx->seqStore.maxNbSeq, externalSequences_invalid,
@@ -6463,7 +6463,7 @@ ZSTD_copySequencesToSeqStoreNoBlockDelim(ZSTD_CCtx* cctx, ZSTD_sequencePosition*
if (cctx->appliedParams.validateSequences) {
seqPos->posInSrc += litLength + matchLength;
FORWARD_IF_ERROR(ZSTD_validateSequence(offBase, matchLength, cctx->appliedParams.cParams.minMatch, seqPos->posInSrc,
cctx->appliedParams.cParams.windowLog, dictSize, cctx->appliedParams.useExternalMatchFinder),
cctx->appliedParams.cParams.windowLog, dictSize, cctx->appliedParams.useSequenceProducer),
"Sequence validation failed");
}
DEBUGLOG(6, "Storing sequence: (of: %u, ml: %u, ll: %u)", offBase, matchLength, litLength);
@@ -6908,9 +6908,9 @@ ZSTD_parameters ZSTD_getParams(int compressionLevel, unsigned long long srcSizeH
return ZSTD_getParams_internal(compressionLevel, srcSizeHint, dictSize, ZSTD_cpm_unknown);
}
void ZSTD_registerExternalMatchFinder(
void ZSTD_registerSequenceProducer(
ZSTD_CCtx* zc, void* mState,
ZSTD_externalMatchFinder_F* mFinder
ZSTD_sequenceProducer_F* mFinder
) {
if (mFinder != NULL) {
ZSTD_externalMatchCtx emctx;
@@ -6919,9 +6919,9 @@ void ZSTD_registerExternalMatchFinder(
emctx.seqBuffer = NULL;
emctx.seqBufferCapacity = 0;
zc->externalMatchCtx = emctx;
zc->requestedParams.useExternalMatchFinder = 1;
zc->requestedParams.useSequenceProducer = 1;
} else {
ZSTD_memset(&zc->externalMatchCtx, 0, sizeof(zc->externalMatchCtx));
zc->requestedParams.useExternalMatchFinder = 0;
zc->requestedParams.useSequenceProducer = 0;
}
}
lib/compress/zstd_compress_internal.h
+3 -3
View File
@@ -353,8 +353,8 @@ struct ZSTD_CCtx_params_s {
/* Indicates whether an external matchfinder has been referenced.
* Users can't set this externally.
* It is set internally in ZSTD_registerExternalMatchFinder(). */
int useExternalMatchFinder;
* It is set internally in ZSTD_registerSequenceProducer(). */
int useSequenceProducer;
/* Adjust the max block size*/
size_t maxBlockSize;
@@ -395,7 +395,7 @@ typedef struct {
/* Context for block-level external matchfinder API */
typedef struct {
void* mState;
ZSTD_externalMatchFinder_F* mFinder;
ZSTD_sequenceProducer_F* mFinder;
ZSTD_Sequence* seqBuffer;
size_t seqBufferCapacity;
} ZSTD_externalMatchCtx;
lib/zstd.h
+106 -95
View File
@@ -478,7 +478,7 @@ typedef enum {
* ZSTD_c_useBlockSplitter
* ZSTD_c_useRowMatchFinder
* ZSTD_c_prefetchCDictTables
* ZSTD_c_enableMatchFinderFallback
* ZSTD_c_enableSeqProducerFallback
* ZSTD_c_maxBlockSize
* Because they are not stable, it's necessary to define ZSTD_STATIC_LINKING_ONLY to access them.
* note : never ever use experimentalParam? names directly;
@@ -565,7 +565,7 @@ typedef enum {
* They will be used to compress next frame.
* Resetting session never fails.
* - The parameters : changes all parameters back to "default".
* This also removes any reference to any dictionary or external matchfinder.
* This also removes any reference to any dictionary or external sequence producer.
* Parameters can only be changed between 2 sessions (i.e. no compression is currently ongoing)
* otherwise the reset fails, and function returns an error value (which can be tested using ZSTD_isError())
* - Both : similar to resetting the session, followed by resetting parameters.
@@ -1627,8 +1627,8 @@ ZSTDLIB_API unsigned ZSTD_isSkippableFrame(const void* buffer, size_t size);
* Note : only single-threaded compression is supported.
* ZSTD_estimateCCtxSize_usingCCtxParams() will return an error code if ZSTD_c_nbWorkers is >= 1.
*
* Note 2 : ZSTD_estimateCCtxSize* functions are not compatible with the external matchfinder API at this time.
* Size estimates assume that no external matchfinder is registered.
* Note 2 : ZSTD_estimateCCtxSize* functions are not compatible with the Block-Level Sequence Producer API at this time.
* Size estimates assume that no external sequence producer is registered.
*/
ZSTDLIB_STATIC_API size_t ZSTD_estimateCCtxSize(int compressionLevel);
ZSTDLIB_STATIC_API size_t ZSTD_estimateCCtxSize_usingCParams(ZSTD_compressionParameters cParams);
@@ -1650,8 +1650,8 @@ ZSTDLIB_STATIC_API size_t ZSTD_estimateDCtxSize(void);
* In this case, get total size by adding ZSTD_estimate?DictSize
* Note 2 : only single-threaded compression is supported.
* ZSTD_estimateCStreamSize_usingCCtxParams() will return an error code if ZSTD_c_nbWorkers is >= 1.
* Note 3 : ZSTD_estimateCStreamSize* functions are not compatible with the external matchfinder API at this time.
* Size estimates assume that no external matchfinder is registered.
* Note 3 : ZSTD_estimateCStreamSize* functions are not compatible with the Block-Level Sequence Producer API at this time.
* Size estimates assume that no external sequence producer is registered.
*/
ZSTDLIB_STATIC_API size_t ZSTD_estimateCStreamSize(int compressionLevel);
ZSTDLIB_STATIC_API size_t ZSTD_estimateCStreamSize_usingCParams(ZSTD_compressionParameters cParams);
@@ -2113,19 +2113,19 @@ ZSTDLIB_STATIC_API size_t ZSTD_CCtx_refPrefix_advanced(ZSTD_CCtx* cctx, const vo
*/
#define ZSTD_c_prefetchCDictTables ZSTD_c_experimentalParam16
/* ZSTD_c_enableMatchFinderFallback
/* ZSTD_c_enableSeqProducerFallback
* Allowed values are 0 (disable) and 1 (enable). The default setting is 0.
*
* Controls whether zstd will fall back to an internal matchfinder if an
* external matchfinder is registered and returns an error code. This fallback is
* block-by-block: the internal matchfinder will only be called for blocks where
* the external matchfinder returns an error code. Fallback compression will
* Controls whether zstd will fall back to an internal sequence producer if an
* external sequence producer is registered and returns an error code. This fallback
* is block-by-block: the internal sequence producer will only be called for blocks
* where the external sequence producer returns an error code. Fallback parsing will
* follow any other cParam settings, such as compression level, the same as in a
* normal (fully-internal) compression operation.
*
* The user is strongly encouraged to read the full external matchfinder API
* The user is strongly encouraged to read the full Block-Level Sequence Producer API
* documentation (below) before setting this parameter. */
#define ZSTD_c_enableMatchFinderFallback ZSTD_c_experimentalParam17
#define ZSTD_c_enableSeqProducerFallback ZSTD_c_experimentalParam17
/* ZSTD_c_maxBlockSize
* Allowed values are between 1KB and ZSTD_BLOCKSIZE_MAX (128KB).
@@ -2141,12 +2141,13 @@ ZSTDLIB_STATIC_API size_t ZSTD_CCtx_refPrefix_advanced(ZSTD_CCtx* cctx, const vo
/* ZSTD_c_searchForExternalRepcodes
* This parameter affects how zstd parses external sequences, such as sequences
* provided through the compressSequences() API or from an external matchfinder.
* provided through the compressSequences() API or from an external block-level
* sequence producer.
*
* If set to ZSTD_ps_enable, the library will check for repeated offsets in
* external sequences, even if those repcodes are not explicitly indicated in
* the "rep" field. Note that this is the only way to exploit repcode matches
* while using compressSequences() or an external matchfinder, since zstd
* while using compressSequences() or an external sequence producer, since zstd
* currently ignores the "rep" field of external sequences.
*
* If set to ZSTD_ps_disable, the library will not exploit repeated offsets in
@@ -2805,43 +2806,52 @@ ZSTDLIB_STATIC_API size_t ZSTD_decompressBlock(ZSTD_DCtx* dctx, void* dst, size_
ZSTDLIB_STATIC_API size_t ZSTD_insertBlock (ZSTD_DCtx* dctx, const void* blockStart, size_t blockSize); /**< insert uncompressed block into `dctx` history. Useful for multi-blocks decompression. */
/* ********************** EXTERNAL MATCHFINDER API **********************
/* ********************* BLOCK-LEVEL SEQUENCE PRODUCER API *********************
*
* *** OVERVIEW ***
* This API allows users to replace the zstd internal block-level matchfinder
* with an external matchfinder function. Potential applications of the API
* include hardware-accelerated matchfinders and matchfinders specialized to
* particular types of data.
* The Block-Level Sequence Producer API allows users to provide their own custom
* sequence producer which libzstd invokes to process each block. The produced list
* of sequences (literals and matches) is then post-processed by libzstd to produce
* valid compressed blocks.
*
* See contrib/externalMatchfinder for an example program employing the
* external matchfinder API.
* This block-level offload API is a more granular complement of the existing
* frame-level offload API compressSequences() (introduced in v1.5.1). It offers
* an easier migration story for applications already integrated with libzstd: the
* user application continues to invoke the same compression functions
* ZSTD_compress2() or ZSTD_compressStream2() as usual, and transparently benefits
* from the specific advantages of the external sequence producer. For example,
* the sequence producer could be tuned to take advantage of known characteristics
* of the input, to offer better speed / ratio, or could leverage hardware
* acceleration not available within libzstd itself.
*
* See contrib/externalSequenceProducer for an example program employing the
* Block-Level Sequence Producer API.
*
* *** USAGE ***
* The user is responsible for implementing a function of type
* ZSTD_externalMatchFinder_F. For each block, zstd will pass the following
* ZSTD_sequenceProducer_F. For each block, zstd will pass the following
* arguments to the user-provided function:
*
* - externalMatchState: a pointer to a user-managed state for the external
* matchfinder.
* - sequenceProducerState: a pointer to a user-managed state for the sequence
* producer.
*
* - outSeqs, outSeqsCapacity: an output buffer for sequences produced by the
* external matchfinder. outSeqsCapacity is guaranteed >=
* ZSTD_sequenceBound(srcSize). The memory backing outSeqs is managed by
* the CCtx.
* - outSeqs, outSeqsCapacity: an output buffer for the sequence producer.
* outSeqsCapacity is guaranteed >= ZSTD_sequenceBound(srcSize). The memory
* backing outSeqs is managed by the CCtx.
*
* - src, srcSize: an input buffer which the external matchfinder must parse
* into sequences. srcSize is guaranteed to be <= ZSTD_BLOCKSIZE_MAX.
* - src, srcSize: an input buffer for the sequence producer to parse.
* srcSize is guaranteed to be <= ZSTD_BLOCKSIZE_MAX.
*
* - dict, dictSize: a history buffer, which may be empty, which the external
* matchfinder may reference as it produces sequences for the src buffer.
* Currently, zstd will always pass dictSize == 0 into external matchfinders,
* but this will change in the future.
* - dict, dictSize: a history buffer, which may be empty, which the sequence
* producer may reference as it parses the src buffer. Currently, zstd will
* always pass dictSize == 0 into external sequence producers, but this will
* change in the future.
*
* - compressionLevel: a signed integer representing the zstd compression level
* set by the user for the current operation. The external matchfinder may
* choose to use this information to change its compression strategy and
* speed/ratio tradeoff. Note: The compression level does not reflect zstd
* parameters set through the advanced API.
* set by the user for the current operation. The sequence producer may choose
* to use this information to change its compression strategy and speed/ratio
* tradeoff. Note: the compression level does not reflect zstd parameters set
* through the advanced API.
*
* - windowSize: a size_t representing the maximum allowed offset for external
* sequences. Note that sequence offsets are sometimes allowed to exceed the
@@ -2851,7 +2861,7 @@ ZSTDLIB_STATIC_API size_t ZSTD_insertBlock (ZSTD_DCtx* dctx, const void* bloc
* The user-provided function shall return a size_t representing the number of
* sequences written to outSeqs. This return value will be treated as an error
* code if it is greater than outSeqsCapacity. The return value must be non-zero
* if srcSize is non-zero. The ZSTD_EXTERNAL_MATCHFINDER_ERROR macro is provided
* if srcSize is non-zero. The ZSTD_SEQUENCE_PRODUCER_ERROR macro is provided
* for convenience, but any value greater than outSeqsCapacity will be treated as
* an error code.
*
@@ -2859,68 +2869,71 @@ ZSTDLIB_STATIC_API size_t ZSTD_insertBlock (ZSTD_DCtx* dctx, const void* bloc
* written to outSeqs must be a valid parse of the src buffer. Data corruption may
* occur if the parse is not valid. A parse is defined to be valid if the
* following conditions hold:
* - The sum of matchLengths and literalLengths is equal to srcSize.
* - All sequences in the parse have matchLength != 0, except for the final
* sequence. matchLength is not constrained for the final sequence.
* - All offsets respect the windowSize parameter as specified in
* - The sum of matchLengths and literalLengths must equal srcSize.
* - All sequences in the parse, except for the final sequence, must have
* matchLength >= ZSTD_MINMATCH_MIN. The final sequence must have
* matchLength >= ZSTD_MINMATCH_MIN or matchLength == 0.
* - All offsets must respect the windowSize parameter as specified in
* doc/zstd_compression_format.md.
* - If the final sequence has matchLength == 0, it must also have offset == 0.
*
* zstd will only validate these conditions (and fail compression if they do not
* hold) if the ZSTD_c_validateSequences cParam is enabled. Note that sequence
* validation has a performance cost.
*
* If the user-provided function returns an error, zstd will either fall back
* to an internal matchfinder or fail the compression operation. The user can
* choose between the two behaviors by setting the
* ZSTD_c_enableMatchFinderFallback cParam. Fallback compression will follow any
* other cParam settings, such as compression level, the same as in a normal
* compression operation.
* to an internal sequence producer or fail the compression operation. The user can
* choose between the two behaviors by setting the ZSTD_c_enableSeqProducerFallback
* cParam. Fallback compression will follow any other cParam settings, such as
* compression level, the same as in a normal compression operation.
*
* The user shall instruct zstd to use a particular ZSTD_externalMatchFinder_F
* function by calling ZSTD_registerExternalMatchFinder(cctx, externalMatchState,
* externalMatchFinder). This setting will persist until the next parameter reset
* of the CCtx.
* The user shall instruct zstd to use a particular ZSTD_sequenceProducer_F
* function by calling
* ZSTD_registerSequenceProducer(cctx,
* sequenceProducerState,
* sequenceProducer)
* This setting will persist until the next parameter reset of the CCtx.
*
* The externalMatchState must be initialized by the user before calling
* ZSTD_registerExternalMatchFinder. The user is responsible for destroying the
* externalMatchState.
* The sequenceProducerState must be initialized by the user before calling
* ZSTD_registerSequenceProducer(). The user is responsible for destroying the
* sequenceProducerState.
*
* *** LIMITATIONS ***
* External matchfinders are compatible with all zstd compression APIs which respect
* advanced parameters. However, there are three limitations:
* This API is compatible with all zstd compression APIs which respect advanced parameters.
* However, there are three limitations:
*
* First, the ZSTD_c_enableLongDistanceMatching cParam is not supported.
* COMPRESSION WILL FAIL if it is enabled and the user tries to compress with an
* external matchfinder.
* - Note that ZSTD_c_enableLongDistanceMatching is auto-enabled by default in
* some cases (see its documentation for details). Users must explicitly set
* ZSTD_c_enableLongDistanceMatching to ZSTD_ps_disable in such cases if an
* external matchfinder is registered.
* First, the ZSTD_c_enableLongDistanceMatching cParam is not currently supported.
* COMPRESSION WILL FAIL if it is enabled and the user tries to compress with a block-level
* external sequence producer.
* - Note that ZSTD_c_enableLongDistanceMatching is auto-enabled by default in some
* cases (see its documentation for details). Users must explicitly set
* ZSTD_c_enableLongDistanceMatching to ZSTD_ps_disable in such cases if an external
* sequence producer is registered.
* - As of this writing, ZSTD_c_enableLongDistanceMatching is disabled by default
* whenever ZSTD_c_windowLog < 128MB, but that's subject to change. Users should
* check the docs on ZSTD_c_enableLongDistanceMatching whenever the external
* matchfinder API is used in conjunction with advanced settings (like windowLog).
* check the docs on ZSTD_c_enableLongDistanceMatching whenever the Block-Level Sequence
* Producer API is used in conjunction with advanced settings (like ZSTD_c_windowLog).
*
* Second, history buffers are not supported. Concretely, zstd will always pass
* dictSize == 0 to the external matchfinder (for now). This has two implications:
* - Dictionaries are not supported. Compression will *not* fail if the user
* Second, history buffers are not currently supported. Concretely, zstd will always pass
* dictSize == 0 to the external sequence producer (for now). This has two implications:
* - Dictionaries are not currently supported. Compression will *not* fail if the user
* references a dictionary, but the dictionary won't have any effect.
* - Stream history is not supported. All compression APIs, including streaming
* APIs, work with the external matchfinder, but the external matchfinder won't
* receive any history from the previous block. Each block is an independent chunk.
* - Stream history is not currently supported. All advanced compression APIs, including
* streaming APIs, work with external sequence producers, but each block is treated as
* an independent chunk without history from previous blocks.
*
* Third, multi-threading within a single compression is not supported. In other words,
* COMPRESSION WILL FAIL if ZSTD_c_nbWorkers > 0 and an external matchfinder is registered.
* Third, multi-threading within a single compression is not currently supported. In other words,
* COMPRESSION WILL FAIL if ZSTD_c_nbWorkers > 0 and an external sequence producer is registered.
* Multi-threading across compressions is fine: simply create one CCtx per thread.
*
* Long-term, we plan to overcome all three limitations. There is no technical blocker to
* overcoming them. It is purely a question of engineering effort.
*/
#define ZSTD_EXTERNAL_MATCHFINDER_ERROR ((size_t)(-1))
#define ZSTD_SEQUENCE_PRODUCER_ERROR ((size_t)(-1))
typedef size_t ZSTD_externalMatchFinder_F (
void* externalMatchState,
typedef size_t ZSTD_sequenceProducer_F (
void* sequenceProducerState,
ZSTD_Sequence* outSeqs, size_t outSeqsCapacity,
const void* src, size_t srcSize,
const void* dict, size_t dictSize,
@@ -2928,32 +2941,30 @@ typedef size_t ZSTD_externalMatchFinder_F (
size_t windowSize
);
/*! ZSTD_registerExternalMatchFinder() :
* Instruct zstd to use an external matchfinder function.
/*! ZSTD_registerSequenceProducer() :
* Instruct zstd to use a block-level external sequence producer function.
*
* The externalMatchState must be initialized by the caller, and the caller is
* The sequenceProducerState must be initialized by the caller, and the caller is
* responsible for managing its lifetime. This parameter is sticky across
* compressions. It will remain set until the user explicitly resets compression
* parameters.
*
* External matchfinder registration is considered to be an "advanced parameter",
* part of the "advanced API". This means it will only have an effect on
* compression APIs which respect advanced parameters, such as compress2() and
* compressStream(). Older compression APIs such as compressCCtx(), which predate
* the introduction of "advanced parameters", will ignore any external matchfinder
* setting.
* Sequence producer registration is considered to be an "advanced parameter",
* part of the "advanced API". This means it will only have an effect on compression
* APIs which respect advanced parameters, such as compress2() and compressStream2().
* Older compression APIs such as compressCCtx(), which predate the introduction of
* "advanced parameters", will ignore any external sequence producer setting.
*
* The external matchfinder can be "cleared" by registering a NULL external
* matchfinder function pointer. This removes all limitations described above in
* the "LIMITATIONS" section of the API docs.
* The sequence producer can be "cleared" by registering a NULL function pointer. This
* removes all limitations described above in the "LIMITATIONS" section of the API docs.
*
* The user is strongly encouraged to read the full API documentation (above)
* before calling this function. */
* The user is strongly encouraged to read the full API documentation (above) before
* calling this function. */
ZSTDLIB_STATIC_API void
ZSTD_registerExternalMatchFinder(
ZSTD_registerSequenceProducer(
ZSTD_CCtx* cctx,
void* externalMatchState,
ZSTD_externalMatchFinder_F* externalMatchFinder
void* sequenceProducerState,
ZSTD_sequenceProducer_F* sequenceProducer
);
#endif /* ZSTD_H_ZSTD_STATIC_LINKING_ONLY */
lib/zstd_errors.h
+1 -1
View File
@@ -95,7 +95,7 @@ typedef enum {
ZSTD_error_seekableIO = 102,
ZSTD_error_dstBuffer_wrong = 104,
ZSTD_error_srcBuffer_wrong = 105,
ZSTD_error_externalMatchFinder_failed = 106,
ZSTD_error_sequenceProducer_failed = 106,
ZSTD_error_externalSequences_invalid = 107,
ZSTD_error_maxCode = 120 /* never EVER use this value directly, it can change in future versions! Use ZSTD_isError() instead */
} ZSTD_ErrorCode;