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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
2024-12-20 10:36:59 -08:00
parent ca8bd83373
commit 5164d44dab
4 changed files with 23 additions and 16 deletions
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lib/zstd.h
+15 -8
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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() :