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 - The parameters ignored are labled as "superseded-by-cdict" in the ZSTD_cParameter enum docs. + The parameters ignored are labelled as "superseded-by-cdict" in the ZSTD_cParameter enum docs.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()). @@ -867,6 +869,13 @@ size_t ZSTD_freeDStream(ZSTD_DStream* zds);
size_t ZSTD_DCtx_refDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict);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. @@ -995,6 +1004,12 @@ size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict); ZSTD_d_ignoreChecksum = 1 } ZSTD_forceIgnoreChecksum_e;
typedef enum {
+ /* Note: this enum controls ZSTD_d_refMultipleDDicts */
+ ZSTD_rmd_refSingleDDict = 0,
+ ZSTD_rmd_refMultipleDDicts = 1
+} ZSTD_refMultipleDDicts_e;
+typedef enum {
/* Note: this enum and the behavior it controls are effectively internal
* implementation details of the compressor. They are expected to continue
@@ -1073,7 +1088,7 @@ size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict);
`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`.
@@ -1155,6 +1170,22 @@ size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict);
size_t ZSTD_writeSkippableFrame(void* dst, size_t dstCapacity, + const void* src, size_t srcSize, unsigned magicVariant); +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. + +
size_t ZSTD_estimateCCtxSize(int compressionLevel);
@@ -1328,7 +1359,7 @@ ZSTD_customMem const ZSTD_defaultCMem = { NULL, NULL, NULL }; /**< this con
how to interpret prefix content (automatic ? force raw mode (default) ? full mode only ?)
size_t ZSTD_CCtx_getParameter(ZSTD_CCtx* cctx, ZSTD_cParameter param, int* value); +size_t ZSTD_CCtx_getParameter(const ZSTD_CCtx* cctx, ZSTD_cParameter param, int* value);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()). @@ -1382,7 +1413,7 @@ size_t ZSTD_freeCCtxParams(ZSTD_CCtx_params* params);
-size_t ZSTD_CCtxParams_getParameter(ZSTD_CCtx_params* params, ZSTD_cParameter param, int* value); +size_t ZSTD_CCtxParams_getParameter(const ZSTD_CCtx_params* params, ZSTD_cParameter param, int* value);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()).