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Code Issues Releases 1 Activity

change advanced parameter name: ZSTD_c_repcodeResolution

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and updated its documentation.
Note: older name ZSTD_c_searchForExternalRepcodes remains supported via #define
This commit is contained in:
Yann Collet 2024-12-16 13:21:08 -08:00
parent ca8bd83373
commit 5164d44dab
4 changed files with 23 additions and 16 deletions
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12
lib/compress/zstd_compress.c
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@ -634,7 +634,7 @@ ZSTD_bounds ZSTD_cParam_getBounds(ZSTD_cParameter param)
bounds.upperBound = ZSTD_BLOCKSIZE_MAX;
return bounds;
case ZSTD_c_searchForExternalRepcodes:
case ZSTD_c_repcodeResolution:
bounds.lowerBound = (int)ZSTD_ps_auto;
bounds.upperBound = (int)ZSTD_ps_disable;
return bounds;
@ -708,7 +708,7 @@ static int ZSTD_isUpdateAuthorized(ZSTD_cParameter param)
case ZSTD_c_prefetchCDictTables:
case ZSTD_c_enableSeqProducerFallback:
case ZSTD_c_maxBlockSize:
case ZSTD_c_searchForExternalRepcodes:
case ZSTD_c_repcodeResolution:
default:
return 0;
}
@ -768,7 +768,7 @@ size_t ZSTD_CCtx_setParameter(ZSTD_CCtx* cctx, ZSTD_cParameter param, int value)
case ZSTD_c_prefetchCDictTables:
case ZSTD_c_enableSeqProducerFallback:
case ZSTD_c_maxBlockSize:
case ZSTD_c_searchForExternalRepcodes:
case ZSTD_c_repcodeResolution:
break;
default: RETURN_ERROR(parameter_unsupported, "unknown parameter");
@ -1020,8 +1020,8 @@ size_t ZSTD_CCtxParams_setParameter(ZSTD_CCtx_params* CCtxParams,
CCtxParams->maxBlockSize = (size_t)value;
return CCtxParams->maxBlockSize;
case ZSTD_c_searchForExternalRepcodes:
BOUNDCHECK(ZSTD_c_searchForExternalRepcodes, value);
case ZSTD_c_repcodeResolution:
BOUNDCHECK(ZSTD_c_repcodeResolution, value);
CCtxParams->searchForExternalRepcodes = (ZSTD_ParamSwitch_e)value;
return CCtxParams->searchForExternalRepcodes;
@ -1169,7 +1169,7 @@ size_t ZSTD_CCtxParams_getParameter(
case ZSTD_c_maxBlockSize:
*value = (int)CCtxParams->maxBlockSize;
break;
case ZSTD_c_searchForExternalRepcodes:
case ZSTD_c_repcodeResolution:
*value = (int)CCtxParams->searchForExternalRepcodes;
break;
default: RETURN_ERROR(parameter_unsupported, "unknown parameter");

23
lib/zstd.h
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@ -1637,6 +1637,12 @@ ZSTDLIB_STATIC_API size_t ZSTD_mergeBlockDelimiters(ZSTD_Sequence* sequences, si
* If ZSTD_c_blockDelimiters == ZSTD_sf_explicitBlockDelimiters, the array of ZSTD_Sequence is expected to contain
* valid block delimiters (defined in ZSTD_Sequence). Behavior is undefined if no block delimiters are provided.
*
* When ZSTD_c_blockDelimiters == ZSTD_sf_explicitBlockDelimiters, it's possible to decide generating repcodes
* using the advanced parameter ZSTD_c_repcodeResolution. Repcodes will improve compression ratio, though the benefit
* can vary greatly depending on Sequences. On the other hand, repcode resolution is an expensive operation.
* By default, it's disabled at low (<10) compression levels, and enabled above the threshold (>=10).
* ZSTD_c_repcodeResolution makes it possible to directly manage this processing in either direction.
*
* If ZSTD_c_validateSequences == 0, this function blindly accepts the Sequences provided. Invalid Sequences cause undefined
* behavior. If ZSTD_c_validateSequences == 1, then the function will detect invalid Sequences (see doc/zstd_compression_format.md for
* specifics regarding offset/matchlength requirements) and then bail out and return an error.
@ -2301,18 +2307,18 @@ ZSTDLIB_STATIC_API size_t ZSTD_CCtx_refPrefix_advanced(ZSTD_CCtx* cctx, const vo
*/
#define ZSTD_c_maxBlockSize ZSTD_c_experimentalParam18
/* ZSTD_c_searchForExternalRepcodes
* Note: for now, this param only has an effect if ZSTD_c_blockDelimiters is
* set to ZSTD_sf_explicitBlockDelimiters. That may change in the future.
/* ZSTD_c_repcodeResolution
* This parameter only has an effect if ZSTD_c_blockDelimiters is
* set to ZSTD_sf_explicitBlockDelimiters (may change in the future).
*
* This parameter affects how zstd parses external sequences, such as sequences
* provided through compressSequences() and variant API
* This parameter affects how zstd parses external sequences,
* provided via the ZSTD_compressSequences*() API
* or from an external block-level sequence producer.
*
* If set to ZSTD_ps_enable, the library will check for repeated offsets in
* If set to ZSTD_ps_enable, the library will check for repeated offsets within
* 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 sequence producer, 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
@ -2323,7 +2329,8 @@ ZSTDLIB_STATIC_API size_t ZSTD_CCtx_refPrefix_advanced(ZSTD_CCtx* cctx, const vo
* The default value is ZSTD_ps_auto, for which the library will enable/disable
* based on compression level (currently: level<10 disables, level>=10 enables).
*/
#define ZSTD_c_searchForExternalRepcodes ZSTD_c_experimentalParam19
#define ZSTD_c_repcodeResolution ZSTD_c_experimentalParam19
#define ZSTD_c_searchForExternalRepcodes ZSTD_c_experimentalParam19 /* older name */
/*! ZSTD_CCtx_getParameter() :

2
tests/fullbench.c
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@ -618,7 +618,7 @@ local_compressSequencesAndLiterals(const void* input, size_t inputSize,
ZSTD_CCtx_reset(g_zcc, ZSTD_reset_session_and_parameters);
ZSTD_CCtx_setParameter(g_zcc, ZSTD_c_blockDelimiters, ZSTD_sf_explicitBlockDelimiters);
# if 0 /* for tests */
ZSTD_CCtx_setParameter(g_zcc, ZSTD_c_searchForExternalRepcodes, ZSTD_ps_enable);
ZSTD_CCtx_setParameter(g_zcc, ZSTD_c_repcodeResolution, ZSTD_ps_enable);
#endif
assert(8 + nbSeqs * sizeof(ZSTD_Sequence) + nbLiterals == inputSize); (void)inputSize;
(void)payload;

2
tests/fuzz/zstd_helpers.c
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@ -146,7 +146,7 @@ void FUZZ_setRandomParameters(ZSTD_CCtx *cctx, size_t srcSize, FUZZ_dataProducer
setRand(cctx, ZSTD_c_prefetchCDictTables, 0, 2, producer);
setRand(cctx, ZSTD_c_maxBlockSize, ZSTD_BLOCKSIZE_MAX_MIN, ZSTD_BLOCKSIZE_MAX, producer);
setRand(cctx, ZSTD_c_validateSequences, 0, 1, producer);
setRand(cctx, ZSTD_c_searchForExternalRepcodes, 0, 2, producer);
setRand(cctx, ZSTD_c_repcodeResolution, 0, 2, producer);
if (FUZZ_dataProducer_uint32Range(producer, 0, 1) == 0) {
setRand(cctx, ZSTD_c_srcSizeHint, ZSTD_SRCSIZEHINT_MIN, 2 * srcSize, producer);
}