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-<title>zstd 1.4.8 Manual</title>
+<title>zstd 1.4.9 Manual</title>
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-<h1>zstd 1.4.8 Manual</h1>
+<h1>zstd 1.4.9 Manual</h1>
<hr>
<a name="Contents"></a><h2>Contents</h2>
<ol>
* ZSTD_d_format
* ZSTD_d_stableOutBuffer
* ZSTD_d_forceIgnoreChecksum
+ * ZSTD_d_refMultipleDDicts
* Because they are not stable, it's necessary to define ZSTD_STATIC_LINKING_ONLY to access them.
* note : never ever use experimentalParam? names directly
*/
ZSTD_d_experimentalParam1=1000,
ZSTD_d_experimentalParam2=1001,
- ZSTD_d_experimentalParam3=1002
+ ZSTD_d_experimentalParam3=1002,
+ ZSTD_d_experimentalParam4=1003
} ZSTD_dParameter;
</b></pre><BR>
</b><p> Reference a prepared dictionary, to be used for all next compressed frames.
Note that compression parameters are enforced from within CDict,
and supersede any compression parameter previously set within CCtx.
- The parameters ignored are labled as "superseded-by-cdict" in the ZSTD_cParameter enum docs.
+ The parameters ignored are labelled as "superseded-by-cdict" in the ZSTD_cParameter enum docs.
The ignored parameters will be used again if the CCtx is returned to no-dictionary mode.
The dictionary will remain valid for future compressed frames using same CCtx.
@result : 0, or an error code (which can be tested with ZSTD_isError()).
<pre><b>size_t ZSTD_DCtx_refDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict);
</b><p> Reference a prepared dictionary, to be used to decompress next frames.
The dictionary remains active for decompression of future frames using same DCtx.
+
+ If called with ZSTD_d_refMultipleDDicts enabled, repeated calls of this function
+ will store the DDict references in a table, and the DDict used for decompression
+ will be determined at decompression time, as per the dict ID in the frame.
+ The memory for the table is allocated on the first call to refDDict, and can be
+ freed with ZSTD_freeDCtx().
+
@result : 0, or an error code (which can be tested with ZSTD_isError()).
Note 1 : Currently, only one dictionary can be managed.
Referencing a new dictionary effectively "discards" any previous one.
ZSTD_d_ignoreChecksum = 1
} ZSTD_forceIgnoreChecksum_e;
</b></pre><BR>
+<pre><b>typedef enum {
+ </b>/* Note: this enum controls ZSTD_d_refMultipleDDicts */<b>
+ ZSTD_rmd_refSingleDDict = 0,
+ ZSTD_rmd_refMultipleDDicts = 1
+} ZSTD_refMultipleDDicts_e;
+</b></pre><BR>
<pre><b>typedef enum {
</b>/* Note: this enum and the behavior it controls are effectively internal<b>
* implementation details of the compressor. They are expected to continue
`srcSize` must be the _exact_ size of this series
(i.e. there should be a frame boundary at `src + srcSize`)
@return : - upper-bound for the decompressed size of all data in all successive frames
- - if an error occured: ZSTD_CONTENTSIZE_ERROR
+ - if an error occurred: ZSTD_CONTENTSIZE_ERROR
note 1 : an error can occur if `src` contains an invalid or incorrectly formatted frame.
note 2 : the upper-bound is exact when the decompressed size field is available in every ZSTD encoded frame of `src`.
</p></pre><BR>
+<pre><b>size_t ZSTD_writeSkippableFrame(void* dst, size_t dstCapacity,
+ const void* src, size_t srcSize, unsigned magicVariant);
+</b><p> Generates a zstd skippable frame containing data given by src, and writes it to dst buffer.
+
+ Skippable frames begin with a a 4-byte magic number. There are 16 possible choices of magic number,
+ ranging from ZSTD_MAGIC_SKIPPABLE_START to ZSTD_MAGIC_SKIPPABLE_START+15.
+ As such, the parameter magicVariant controls the exact skippable frame magic number variant used, so
+ the magic number used will be ZSTD_MAGIC_SKIPPABLE_START + magicVariant.
+
+ Returns an error if destination buffer is not large enough, if the source size is not representable
+ with a 4-byte unsigned int, or if the parameter magicVariant is greater than 15 (and therefore invalid).
+
+ @return : number of bytes written or a ZSTD error.
+
+</p></pre><BR>
+
<a name="Chapter16"></a><h2>Memory management</h2><pre></pre>
<pre><b>size_t ZSTD_estimateCCtxSize(int compressionLevel);
how to interpret prefix content (automatic ? force raw mode (default) ? full mode only ?)
</p></pre><BR>
-<pre><b>size_t ZSTD_CCtx_getParameter(ZSTD_CCtx* cctx, ZSTD_cParameter param, int* value);
+<pre><b>size_t ZSTD_CCtx_getParameter(const ZSTD_CCtx* cctx, ZSTD_cParameter param, int* value);
</b><p> Get the requested compression parameter value, selected by enum ZSTD_cParameter,
and store it into int* value.
@return : 0, or an error code (which can be tested with ZSTD_isError()).
</p></pre><BR>
-<pre><b>size_t ZSTD_CCtxParams_getParameter(ZSTD_CCtx_params* params, ZSTD_cParameter param, int* value);
+<pre><b>size_t ZSTD_CCtxParams_getParameter(const ZSTD_CCtx_params* params, ZSTD_cParameter param, int* value);
</b><p> Similar to ZSTD_CCtx_getParameter.
Get the requested value of one compression parameter, selected by enum ZSTD_cParameter.
@result : 0, or an error code (which can be tested with ZSTD_isError()).
projects / thirdparty / zstd.git / commitdiff
