[][src]Crate zstd_sys

Structs

ZSTDMT_CCtx_s
ZSTD_CCtx_params_s
ZSTD_CCtx_s
ZSTD_CDict_s
ZSTD_DCtx_s
ZSTD_DDict_s
ZSTD_bounds
ZSTD_compressionParameters
ZSTD_customMem
ZSTD_frameHeader
ZSTD_frameParameters
ZSTD_frameProgression
ZSTD_inBuffer_s

Streaming

ZSTD_outBuffer_s
ZSTD_parameters

Enums

ZSTDMT_parameter
ZSTD_EndDirective
ZSTD_ResetDirective
ZSTD_cParameter
ZSTD_dParameter
ZSTD_dictAttachPref_e
ZSTD_dictContentType_e
ZSTD_dictLoadMethod_e
ZSTD_format_e
ZSTD_frameType_e
ZSTD_nextInputType_e
ZSTD_strategy

Advanced compression API

Constants

ZSTDMT_NBWORKERS_MAX
ZSTD_BLOCKSIZELOG_MAX
ZSTD_BLOCKSIZE_MAX
ZSTD_CHAINLOG_MAX_32
ZSTD_CHAINLOG_MAX_64
ZSTD_CHAINLOG_MIN
ZSTD_CLEVEL_DEFAULT
ZSTD_CONTENTSIZE_ERROR
ZSTD_CONTENTSIZE_UNKNOWN
ZSTD_FRAMEHEADERSIZE_MAX
ZSTD_FRAMEHEADERSIZE_MIN
ZSTD_FRAMEHEADERSIZE_PREFIX
ZSTD_HASHLOG3_MAX
ZSTD_HASHLOG_MIN
ZSTD_LDM_BUCKETSIZELOG_MAX
ZSTD_LDM_BUCKETSIZELOG_MIN
ZSTD_LDM_HASHLOG_MIN
ZSTD_LDM_HASHRATELOG_MIN
ZSTD_LDM_MINMATCH_MAX
ZSTD_LDM_MINMATCH_MIN
ZSTD_MAGICNUMBER
ZSTD_MAGIC_DICTIONARY
ZSTD_MAGIC_SKIPPABLE_MASK
ZSTD_MAGIC_SKIPPABLE_START
ZSTD_MINMATCH_MAX
ZSTD_MINMATCH_MIN
ZSTD_OVERLAPLOG_MAX
ZSTD_OVERLAPLOG_MIN
ZSTD_SEARCHLOG_MIN
ZSTD_SKIPPABLEHEADERSIZE
ZSTD_TARGETLENGTH_MAX
ZSTD_TARGETLENGTH_MIN
ZSTD_VERSION_MAJOR
ZSTD_VERSION_MINOR
ZSTD_VERSION_NUMBER
ZSTD_VERSION_RELEASE
ZSTD_WINDOWLOG_LIMIT_DEFAULT
ZSTD_WINDOWLOG_MAX_32
ZSTD_WINDOWLOG_MAX_64
ZSTD_WINDOWLOG_MIN

Statics

ZSTD_defaultCMem

Functions

ZDICT_getDictID
ZDICT_getErrorName
ZDICT_isError
ZDICT_trainFromBuffer

ZDICT_trainFromBuffer(): Train a dictionary from an array of samples. Redirect towards ZDICT_optimizeTrainFromBuffer_fastCover() single-threaded, with d=8, steps=4, f=20, and accel=1. Samples must be stored concatenated in a single flat buffer samplesBuffer, supplied with an array of sizes samplesSizes, providing the size of each sample, in order. The resulting dictionary will be saved into dictBuffer. @return: size of dictionary stored into dictBuffer (<= dictBufferCapacity) or an error code, which can be tested with ZDICT_isError(). Note: ZDICT_trainFromBuffer() requires about 9 bytes of memory for each input byte. Tips: In general, a reasonable dictionary has a size of ~ 100 KB. It's possible to select smaller or larger size, just by specifying dictBufferCapacity. In general, it's recommended to provide a few thousands samples, though this can vary a lot. It's recommended that total size of all samples be about ~x100 times the target size of dictionary.

ZSTDMT_CCtxParam_setMTCtxParameter

ZSTDMT_CCtxParam_setMTCtxParameter() like ZSTDMT_setMTCtxParameter(), but into a ZSTD_CCtx_Params

ZSTDMT_CCtxParam_setNbWorkers

ZSTDMT_CCtxParam_setNbWorkers() Set nbWorkers, and clamp it. Also reset jobSize and overlapLog

ZSTDMT_compressCCtx
ZSTDMT_compressStream
ZSTDMT_compressStream_generic

ZSTDMT_compressStream_generic() : Combines ZSTDMT_compressStream() with optional ZSTDMT_flushStream() or ZSTDMT_endStream() depending on flush directive. @return : minimum amount of data still to be flushed 0 if fully flushed or an error code note : needs to be init using any ZSTD_initCStream*() variant

ZSTDMT_compress_advanced
ZSTDMT_createCCtx
ZSTDMT_createCCtx_advanced
ZSTDMT_endStream
ZSTDMT_flushStream
ZSTDMT_freeCCtx
ZSTDMT_getFrameProgression

ZSTDMT_getFrameProgression(): tells how much data has been consumed (input) and produced (output) for current frame. able to count progression inside worker threads.

ZSTDMT_getMTCtxParameter
ZSTDMT_initCStream
ZSTDMT_initCStream_advanced
ZSTDMT_initCStream_internal

ZSTDMT_initCStream_internal() : Private use only. Init streaming operation. expects params to be valid. must receive dict, or cdict, or none, but not both. @return : 0, or an error code

ZSTDMT_initCStream_usingCDict
ZSTDMT_nextInputSizeHint
ZSTDMT_resetCStream
ZSTDMT_setMTCtxParameter
ZSTDMT_sizeof_CCtx
ZSTDMT_toFlushNow

ZSTDMT_toFlushNow() Tell how many bytes are ready to be flushed immediately. Probe the oldest active job (not yet entirely flushed) and check its output buffer. If return 0, it means there is no active job, or, it means oldest job is still active, but everything produced has been flushed so far, therefore flushing is limited by speed of oldest job.

ZSTDMT_updateCParams_whileCompressing

ZSTDMT_updateCParams_whileCompressing() : Updates only a selected set of compression parameters, to remain compatible with current frame. New parameters will be applied to next compression job.

ZSTD_CCtxParam_getParameter

ZSTD_CCtxParam_getParameter() : 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()).

ZSTD_CCtxParam_setParameter

ZSTD_CCtxParam_setParameter() : Similar to ZSTD_CCtx_setParameter. Set one compression parameter, selected by enum ZSTD_cParameter. Parameters must be applied to a ZSTD_CCtx using ZSTD_CCtx_setParametersUsingCCtxParams(). @result : 0, or an error code (which can be tested with ZSTD_isError()).

ZSTD_CCtxParams_init

ZSTD_CCtxParams_init() : Initializes the compression parameters of cctxParams according to compression level. All other parameters are reset to their default values.

ZSTD_CCtxParams_init_advanced

ZSTD_CCtxParams_init_advanced() : Initializes the compression and frame parameters of cctxParams according to params. All other parameters are reset to their default values.

ZSTD_CCtxParams_reset

ZSTD_CCtxParams_reset() : Reset params to default values.

ZSTD_CCtx_getParameter

ZSTD_CCtx_getParameter() : 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()).

ZSTD_CCtx_loadDictionary

ZSTD_CCtx_loadDictionary() : Create an internal CDict from dict buffer. Decompression will have to use same dictionary. @result : 0, or an error code (which can be tested with ZSTD_isError()). Special: Loading a NULL (or 0-size) dictionary invalidates previous dictionary, meaning "return to no-dictionary mode". Note 1 : Dictionary is sticky, it will be used for all future compressed frames. To return to "no-dictionary" situation, load a NULL dictionary (or reset parameters). Note 2 : Loading a dictionary involves building tables. It's also a CPU consuming operation, with non-negligible impact on latency. Tables are dependent on compression parameters, and for this reason, compression parameters can no longer be changed after loading a dictionary. Note 3 :dict content will be copied internally. Use experimental ZSTD_CCtx_loadDictionary_byReference() to reference content instead. In such a case, dictionary buffer must outlive its users. Note 4 : Use ZSTD_CCtx_loadDictionary_advanced() to precisely select how dictionary content must be interpreted.

ZSTD_CCtx_loadDictionary_advanced

ZSTD_CCtx_loadDictionary_advanced() : Same as ZSTD_CCtx_loadDictionary(), but gives finer control over how to load the dictionary (by copy ? by reference ?) and how to interpret it (automatic ? force raw mode ? full mode only ?)

ZSTD_CCtx_loadDictionary_byReference

ZSTD_CCtx_loadDictionary_byReference() : Same as ZSTD_CCtx_loadDictionary(), but dictionary content is referenced, instead of being copied into CCtx. It saves some memory, but also requires that dict outlives its usage within cctx

ZSTD_CCtx_refCDict

ZSTD_CCtx_refCDict() : Reference a prepared dictionary, to be used for all next compressed frames. Note that compression parameters are enforced from within CDict, and supercede any compression parameter previously set within CCtx. 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()). Special : Referencing a NULL CDict means "return to no-dictionary mode". Note 1 : Currently, only one dictionary can be managed. Referencing a new dictionary effectively "discards" any previous one. Note 2 : CDict is just referenced, its lifetime must outlive its usage within CCtx.

ZSTD_CCtx_refPrefix

ZSTD_CCtx_refPrefix() : Reference a prefix (single-usage dictionary) for next compressed frame. A prefix is only used once. Tables are discarded at end of frame (ZSTD_e_end). Decompression will need same prefix to properly regenerate data. Compressing with a prefix is similar in outcome as performing a diff and compressing it, but performs much faster, especially during decompression (compression speed is tunable with compression level). @result : 0, or an error code (which can be tested with ZSTD_isError()). Special: Adding any prefix (including NULL) invalidates any previous prefix or dictionary Note 1 : Prefix buffer is referenced. It must outlive compression. Its content must remain unmodified during compression. Note 2 : If the intention is to diff some large src data blob with some prior version of itself, ensure that the window size is large enough to contain the entire source. See ZSTD_c_windowLog. Note 3 : Referencing a prefix involves building tables, which are dependent on compression parameters. It's a CPU consuming operation, with non-negligible impact on latency. If there is a need to use the same prefix multiple times, consider loadDictionary instead. Note 4 : By default, the prefix is interpreted as raw content (ZSTD_dm_rawContent). Use experimental ZSTD_CCtx_refPrefix_advanced() to alter dictionary interpretation.

ZSTD_CCtx_refPrefix_advanced

ZSTD_CCtx_refPrefix_advanced() : Same as ZSTD_CCtx_refPrefix(), but gives finer control over how to interpret prefix content (automatic ? force raw mode (default) ? full mode only ?)

ZSTD_CCtx_reset

ZSTD_CCtx_reset() : There are 2 different things that can be reset, independently or jointly :

ZSTD_CCtx_setParameter

ZSTD_CCtx_setParameter() : Set one compression parameter, selected by enum ZSTD_cParameter. All parameters have valid bounds. Bounds can be queried using ZSTD_cParam_getBounds(). Providing a value beyond bound will either clamp it, or trigger an error (depending on parameter). Setting a parameter is generally only possible during frame initialization (before starting compression). Exception : when using multi-threading mode (nbWorkers >= 1), the following parameters can be updated during compression (within same frame): => compressionLevel, hashLog, chainLog, searchLog, minMatch, targetLength and strategy. new parameters will be active for next job only (after a flush()). @return : an error code (which can be tested using ZSTD_isError()).

ZSTD_CCtx_setParametersUsingCCtxParams

ZSTD_CCtx_setParametersUsingCCtxParams() : Apply a set of ZSTD_CCtx_params to the compression context. This can be done even after compression is started, if nbWorkers==0, this will have no impact until a new compression is started. if nbWorkers>=1, new parameters will be picked up at next job, with a few restrictions (windowLog, pledgedSrcSize, nbWorkers, jobSize, and overlapLog are not updated).

ZSTD_CCtx_setPledgedSrcSize

ZSTD_CCtx_setPledgedSrcSize() : Total input data size to be compressed as a single frame. Value will be written in frame header, unless if explicitly forbidden using ZSTD_c_contentSizeFlag. This value will also be controlled at end of frame, and trigger an error if not respected. @result : 0, or an error code (which can be tested with ZSTD_isError()). Note 1 : pledgedSrcSize==0 actually means zero, aka an empty frame. In order to mean "unknown content size", pass constant ZSTD_CONTENTSIZE_UNKNOWN. ZSTD_CONTENTSIZE_UNKNOWN is default value for any new frame. Note 2 : pledgedSrcSize is only valid once, for the next frame. It's discarded at the end of the frame, and replaced by ZSTD_CONTENTSIZE_UNKNOWN. Note 3 : Whenever all input data is provided and consumed in a single round, for example with ZSTD_compress2(), or invoking immediately ZSTD_compressStream2(,,,ZSTD_e_end), this value is automatically overriden by srcSize instead.

ZSTD_CStreamInSize
ZSTD_CStreamOutSize
ZSTD_DCtx_loadDictionary

ZSTD_DCtx_loadDictionary() : Create an internal DDict from dict buffer, to be used to decompress next frames. The dictionary remains valid for all future frames, until explicitly invalidated. @result : 0, or an error code (which can be tested with ZSTD_isError()). Special : Adding a NULL (or 0-size) dictionary invalidates any previous dictionary, meaning "return to no-dictionary mode". Note 1 : Loading a dictionary involves building tables, which has a non-negligible impact on CPU usage and latency. It's recommended to "load once, use many times", to amortize the cost Note 2 :dict content will be copied internally, so dict can be released after loading. Use ZSTD_DCtx_loadDictionary_byReference() to reference dictionary content instead. Note 3 : Use ZSTD_DCtx_loadDictionary_advanced() to take control of how dictionary content is loaded and interpreted.

ZSTD_DCtx_loadDictionary_advanced

ZSTD_DCtx_loadDictionary_advanced() : Same as ZSTD_DCtx_loadDictionary(), but gives direct control over how to load the dictionary (by copy ? by reference ?) and how to interpret it (automatic ? force raw mode ? full mode only ?).

ZSTD_DCtx_loadDictionary_byReference

ZSTD_DCtx_loadDictionary_byReference() : Same as ZSTD_DCtx_loadDictionary(), but references dict content instead of copying it into dctx. This saves memory if dict remains around., However, it's imperative that dict remains accessible (and unmodified) while being used, so it must outlive decompression.

ZSTD_DCtx_refDDict

ZSTD_DCtx_refDDict() : Reference a prepared dictionary, to be used to decompress next frames. The dictionary remains active for decompression of future frames using same DCtx. @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. Special: referencing a NULL DDict means "return to no-dictionary mode". Note 2 : DDict is just referenced, its lifetime must outlive its usage from DCtx.

ZSTD_DCtx_refPrefix

ZSTD_DCtx_refPrefix() : Reference a prefix (single-usage dictionary) to decompress next frame. This is the reverse operation of ZSTD_CCtx_refPrefix(), and must use the same prefix as the one used during compression. Prefix is only used once. Reference is discarded at end of frame. End of frame is reached when ZSTD_decompressStream() returns 0. @result : 0, or an error code (which can be tested with ZSTD_isError()). Note 1 : Adding any prefix (including NULL) invalidates any previously set prefix or dictionary Note 2 : Prefix buffer is referenced. It must outlive decompression. Prefix buffer must remain unmodified up to the end of frame, reached when ZSTD_decompressStream() returns 0. Note 3 : By default, the prefix is treated as raw content (ZSTD_dm_rawContent). Use ZSTD_CCtx_refPrefix_advanced() to alter dictMode (Experimental section) Note 4 : Referencing a raw content prefix has almost no cpu nor memory cost. A full dictionary is more costly, as it requires building tables.

ZSTD_DCtx_refPrefix_advanced

ZSTD_DCtx_refPrefix_advanced() : Same as ZSTD_DCtx_refPrefix(), but gives finer control over how to interpret prefix content (automatic ? force raw mode (default) ? full mode only ?)

ZSTD_DCtx_reset

ZSTD_DCtx_reset() : Return a DCtx to clean state. Session and parameters can be reset jointly or separately. Parameters can only be reset when no active frame is being decompressed. @return : 0, or an error code, which can be tested with ZSTD_isError()

ZSTD_DCtx_setFormat

ZSTD_DCtx_setFormat() : Instruct the decoder context about what kind of data to decode next. This instruction is mandatory to decode data without a fully-formed header, such ZSTD_f_zstd1_magicless for example. @return : 0, or an error code (which can be tested using ZSTD_isError()).

ZSTD_DCtx_setMaxWindowSize

ZSTD_DCtx_setMaxWindowSize() : Refuses allocating internal buffers for frames requiring a window size larger than provided limit. This protects a decoder context from reserving too much memory for itself (potential attack scenario). This parameter is only useful in streaming mode, since no internal buffer is allocated in single-pass mode. By default, a decompression context accepts all window sizes <= (1 << ZSTD_WINDOWLOG_LIMIT_DEFAULT) @return : 0, or an error code (which can be tested using ZSTD_isError()).

ZSTD_DCtx_setParameter

ZSTD_DCtx_setParameter() : Set one compression parameter, selected by enum ZSTD_dParameter. All parameters have valid bounds. Bounds can be queried using ZSTD_dParam_getBounds(). Providing a value beyond bound will either clamp it, or trigger an error (depending on parameter). Setting a parameter is only possible during frame initialization (before starting decompression). @return : 0, or an error code (which can be tested using ZSTD_isError()).

ZSTD_DStreamInSize
ZSTD_DStreamOutSize
ZSTD_adjustCParams

ZSTD_adjustCParams() : optimize params for a given srcSize and dictSize. both values are optional, select 0 if unknown.

ZSTD_cParam_getBounds

ZSTD_cParam_getBounds() : All parameters must belong to an interval with lower and upper bounds, otherwise they will either trigger an error or be automatically clamped. @return : a structure, ZSTD_bounds, which contains - an error status field, which must be tested using ZSTD_isError() - lower and upper bounds, both inclusive

ZSTD_checkCParams

ZSTD_checkCParams() : Ensure param values remain within authorized range

ZSTD_compress

Simple API Compresses src content as a single zstd compressed frame into already allocated dst. Hint : compression runs faster if dstCapacity >= ZSTD_compressBound(srcSize). @return : compressed size written into dst (<= `dstCapacity), or an error code if it fails (which can be tested using ZSTD_isError()).

ZSTD_compress2

ZSTD_compress2() : Behave the same as ZSTD_compressCCtx(), but compression parameters are set using the advanced API. ZSTD_compress2() always starts a new frame. Should cctx hold data from a previously unfinished frame, everything about it is forgotten.

ZSTD_compressBegin

Buffer-less streaming compression (synchronous mode)

ZSTD_compressBegin_advanced
ZSTD_compressBegin_usingCDict
ZSTD_compressBegin_usingCDict_advanced
ZSTD_compressBegin_usingDict
ZSTD_compressBlock
ZSTD_compressBound
ZSTD_compressCCtx

ZSTD_compressCCtx() : Same as ZSTD_compress(), using an explicit ZSTD_CCtx The function will compress at requested compression level, ignoring any other parameter

ZSTD_compressContinue
ZSTD_compressEnd
ZSTD_compressStream
ZSTD_compressStream2

ZSTD_compressStream2() : Behaves about the same as ZSTD_compressStream, with additional control on end directive.

ZSTD_compressStream2_simpleArgs

ZSTD_compressStream2_simpleArgs() : Same as ZSTD_compressStream2(), but using only integral types as arguments. This variant might be helpful for binders from dynamic languages which have troubles handling structures containing memory pointers.

ZSTD_compress_advanced

ZSTD_compress_advanced() : Same as ZSTD_compress_usingDict(), with fine-tune control over compression parameters (by structure)

ZSTD_compress_usingCDict

ZSTD_compress_usingCDict() : Compression using a digested Dictionary. Recommended when same dictionary is used multiple times. Note : compression level is decided at dictionary creation time, and frame parameters are hardcoded (dictID=yes, contentSize=yes, checksum=no)

ZSTD_compress_usingCDict_advanced

ZSTD_compress_usingCDict_advanced() : Same as ZSTD_compress_usingCDict(), with fine-tune control over frame parameters

ZSTD_compress_usingDict

Simple dictionary API Compression at an explicit compression level using a Dictionary. A dictionary can be any arbitrary data segment (also called a prefix), or a buffer with specified information (see dictBuilder/zdict.h). Note : This function loads the dictionary, resulting in significant startup delay. It's intended for a dictionary used only once. Note 2 : When dict == NULL || dictSize < 8 no dictionary is used.

ZSTD_copyCCtx
ZSTD_copyDCtx
ZSTD_createCCtx
ZSTD_createCCtxParams

ZSTD_CCtx_params : Quick howto :

ZSTD_createCCtx_advanced
ZSTD_createCDict

ZSTD_createCDict() : When compressing multiple messages / blocks using the same dictionary, it's recommended to load it only once. ZSTD_createCDict() will create a digested dictionary, ready to start future compression operations without startup cost. ZSTD_CDict can be created once and shared by multiple threads concurrently, since its usage is read-only. dictBuffer can be released after ZSTD_CDict creation, because its content is copied within CDict. Consider experimental function ZSTD_createCDict_byReference() if you prefer to not duplicate dictBuffer content. Note : A ZSTD_CDict can be created from an empty dictBuffer, but it is inefficient when used to compress small data.

ZSTD_createCDict_advanced
ZSTD_createCDict_byReference

ZSTD_createCDict_byReference() : Create a digested dictionary for compression Dictionary content is just referenced, not duplicated. As a consequence, dictBuffer must outlive CDict, and its content must remain unmodified throughout the lifetime of CDict.

ZSTD_createCStream
ZSTD_createCStream_advanced
ZSTD_createDCtx
ZSTD_createDCtx_advanced
ZSTD_createDDict

ZSTD_createDDict() : Create a digested dictionary, ready to start decompression operation without startup delay. dictBuffer can be released after DDict creation, as its content is copied inside DDict.

ZSTD_createDDict_advanced
ZSTD_createDDict_byReference

ZSTD_createDDict_byReference() : Create a digested dictionary, ready to start decompression operation without startup delay. Dictionary content is referenced, and therefore stays in dictBuffer. It is important that dictBuffer outlives DDict, it must remain read accessible throughout the lifetime of DDict

ZSTD_createDStream
ZSTD_createDStream_advanced
ZSTD_dParam_getBounds

ZSTD_dParam_getBounds() : All parameters must belong to an interval with lower and upper bounds, otherwise they will either trigger an error or be automatically clamped. @return : a structure, ZSTD_bounds, which contains - an error status field, which must be tested using ZSTD_isError() - both lower and upper bounds, inclusive

ZSTD_decodingBufferSize_min
ZSTD_decompress

ZSTD_decompress() : compressedSize : must be the exact size of some number of compressed and/or skippable frames. dstCapacity is an upper bound of originalSize to regenerate. If user cannot imply a maximum upper bound, it's better to use streaming mode to decompress data. @return : the number of bytes decompressed into dst (<= dstCapacity), or an errorCode if it fails (which can be tested using ZSTD_isError()).

ZSTD_decompressBegin
ZSTD_decompressBegin_usingDDict
ZSTD_decompressBegin_usingDict
ZSTD_decompressBlock
ZSTD_decompressContinue
ZSTD_decompressDCtx

ZSTD_decompressDCtx() : Same as ZSTD_decompress(), requires an allocated ZSTD_DCtx. Compatible with sticky parameters.

ZSTD_decompressStream
ZSTD_decompressStream_simpleArgs

ZSTD_decompressStream_simpleArgs() : Same as ZSTD_decompressStream(), but using only integral types as arguments. This can be helpful for binders from dynamic languages which have troubles handling structures containing memory pointers.

ZSTD_decompress_usingDDict

ZSTD_decompress_usingDDict() : Decompression using a digested Dictionary. Recommended when same dictionary is used multiple times.

ZSTD_decompress_usingDict

ZSTD_decompress_usingDict() : Decompression using a known Dictionary. Dictionary must be identical to the one used during compression. Note : This function loads the dictionary, resulting in significant startup delay. It's intended for a dictionary used only once. Note : When dict == NULL || dictSize < 8 no dictionary is used.

ZSTD_endStream
ZSTD_estimateCCtxSize

ZSTD_estimate*() : These functions make it possible to estimate memory usage of a future {D,C}Ctx, before its creation. ZSTD_estimateCCtxSize() will provide a budget large enough for any compression level up to selected one. It will also consider src size to be arbitrarily "large", which is worst case. If srcSize is known to always be small, ZSTD_estimateCCtxSize_usingCParams() can provide a tighter estimation. ZSTD_estimateCCtxSize_usingCParams() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel. ZSTD_estimateCCtxSize_usingCCtxParams() can be used in tandem with ZSTD_CCtxParam_setParameter(). Only single-threaded compression is supported. This function will return an error code if ZSTD_c_nbWorkers is >= 1. Note : CCtx size estimation is only correct for single-threaded compression.

ZSTD_estimateCCtxSize_usingCCtxParams
ZSTD_estimateCCtxSize_usingCParams
ZSTD_estimateCDictSize

ZSTD_estimate?DictSize() : ZSTD_estimateCDictSize() will bet that src size is relatively "small", and content is copied, like ZSTD_createCDict(). ZSTD_estimateCDictSize_advanced() makes it possible to control compression parameters precisely, like ZSTD_createCDict_advanced(). Note : dictionaries created by reference (ZSTD_dlm_byRef) are logically smaller.

ZSTD_estimateCDictSize_advanced
ZSTD_estimateCStreamSize

ZSTD_estimateCStreamSize() : ZSTD_estimateCStreamSize() will provide a budget large enough for any compression level up to selected one. It will also consider src size to be arbitrarily "large", which is worst case. If srcSize is known to always be small, ZSTD_estimateCStreamSize_usingCParams() can provide a tighter estimation. ZSTD_estimateCStreamSize_usingCParams() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel. ZSTD_estimateCStreamSize_usingCCtxParams() can be used in tandem with ZSTD_CCtxParam_setParameter(). Only single-threaded compression is supported. This function will return an error code if ZSTD_c_nbWorkers is >= 1. Note : CStream size estimation is only correct for single-threaded compression. ZSTD_DStream memory budget depends on window Size. This information can be passed manually, using ZSTD_estimateDStreamSize, or deducted from a valid frame Header, using ZSTD_estimateDStreamSize_fromFrame(); Note : if streaming is init with function ZSTD_init?Stream_usingDict(), an internal ?Dict will be created, which additional size is not estimated here. In this case, get total size by adding ZSTD_estimate?DictSize

ZSTD_estimateCStreamSize_usingCCtxParams
ZSTD_estimateCStreamSize_usingCParams
ZSTD_estimateDCtxSize
ZSTD_estimateDDictSize
ZSTD_estimateDStreamSize
ZSTD_estimateDStreamSize_fromFrame
ZSTD_findDecompressedSize

ZSTD_findDecompressedSize() : src should point the start of a series of ZSTD encoded and/or skippable frames srcSize must be the exact size of this series (i.e. there should be a frame boundary exactly at srcSize bytes after src) @return : - decompressed size of all data in all successive frames - if the decompressed size cannot be determined: ZSTD_CONTENTSIZE_UNKNOWN - if an error occurred: ZSTD_CONTENTSIZE_ERROR

ZSTD_findFrameCompressedSize

ZSTD_findFrameCompressedSize() : src should point to the start of a ZSTD frame or skippable frame. srcSize must be >= first frame size @return : the compressed size of the first frame starting at src, suitable to pass as srcSize to ZSTD_decompress or similar, or an error code if input is invalid

ZSTD_flushStream
ZSTD_frameHeaderSize

ZSTD_frameHeaderSize() : srcSize must be >= ZSTD_FRAMEHEADERSIZE_PREFIX. @return : size of the Frame Header, or an error code (if srcSize is too small)

ZSTD_freeCCtx
ZSTD_freeCCtxParams
ZSTD_freeCDict

ZSTD_freeCDict() : Function frees memory allocated by ZSTD_createCDict().

ZSTD_freeCStream
ZSTD_freeDCtx
ZSTD_freeDDict

ZSTD_freeDDict() : Function frees memory allocated with ZSTD_createDDict()

ZSTD_freeDStream
ZSTD_getBlockSize

Block functions produce and decode raw zstd blocks, without frame metadata. Frame metadata cost is typically ~18 bytes, which can be non-negligible for very small blocks (< 100 bytes). User will have to take in charge required information to regenerate data, such as compressed and content sizes.

ZSTD_getCParams

ZSTD_getCParams() : @return ZSTD_compressionParameters structure for a selected compression level and estimated srcSize. estimatedSrcSize value is optional, select 0 if not known

ZSTD_getDecompressedSize

ZSTD_getDecompressedSize() : NOTE: This function is now obsolete, in favor of ZSTD_getFrameContentSize(). Both functions work the same way, but ZSTD_getDecompressedSize() blends "empty", "unknown" and "error" results to the same return value (0), while ZSTD_getFrameContentSize() gives them separate return values. @return : decompressed size of src frame content if known and not empty, 0 otherwise.

ZSTD_getDictID_fromDDict

ZSTD_getDictID_fromDDict() : Provides the dictID of the dictionary loaded into ddict. If @return == 0, the dictionary is not conformant to Zstandard specification, or empty. Non-conformant dictionaries can still be loaded, but as content-only dictionaries.

ZSTD_getDictID_fromDict

ZSTD_getDictID_fromDict() : Provides the dictID stored within dictionary. if @return == 0, the dictionary is not conformant with Zstandard specification. It can still be loaded, but as a content-only dictionary.

ZSTD_getDictID_fromFrame

ZSTD_getDictID_fromFrame() : Provides the dictID required to decompressed the frame stored within src. If @return == 0, the dictID could not be decoded. This could for one of the following reasons :

ZSTD_getErrorName
ZSTD_getFrameContentSize
ZSTD_getFrameHeader

ZSTD_getFrameHeader() : decode Frame Header, or requires larger srcSize. @return : 0, zfhPtr is correctly filled, >0, srcSize is too small, value is wanted srcSize amount, or an error code, which can be tested using ZSTD_isError()

ZSTD_getFrameHeader_advanced

ZSTD_getFrameHeader_advanced() : same as ZSTD_getFrameHeader(), with added capability to select a format (like ZSTD_f_zstd1_magicless)

ZSTD_getFrameProgression
ZSTD_getParams

ZSTD_getParams() : same as ZSTD_getCParams(), but @return a full ZSTD_parameters object instead of sub-component ZSTD_compressionParameters. All fields of ZSTD_frameParameters are set to default : contentSize=1, checksum=0, noDictID=0

ZSTD_initCStream
ZSTD_initCStream_advanced
ZSTD_initCStream_srcSize

Advanced streaming functions Warning : most of these functions are now redundant with the Advanced API. Once Advanced API reaches "stable" status, redundant functions will be deprecated, and then at some point removed.

ZSTD_initCStream_usingCDict
ZSTD_initCStream_usingCDict_advanced
ZSTD_initCStream_usingDict
ZSTD_initDStream
ZSTD_initDStream_usingDDict
ZSTD_initDStream_usingDict
ZSTD_initStaticCCtx

ZSTD_initStatic*() : Initialize an object using a pre-allocated fixed-size buffer. workspace: The memory area to emplace the object into. Provided pointer must be 8-bytes aligned. Buffer must outlive object. workspaceSize: Use ZSTD_estimate*Size() to determine how large workspace must be to support target scenario. @return : pointer to object (same address as workspace, just different type), or NULL if error (size too small, incorrect alignment, etc.) Note : zstd will never resize nor malloc() when using a static buffer. If the object requires more memory than available, zstd will just error out (typically ZSTD_error_memory_allocation). Note 2 : there is no corresponding "free" function. Since workspace is allocated externally, it must be freed externally too. Note 3 : cParams : use ZSTD_getCParams() to convert a compression level into its associated cParams. Limitation 1 : currently not compatible with internal dictionary creation, triggered by ZSTD_CCtx_loadDictionary(), ZSTD_initCStream_usingDict() or ZSTD_initDStream_usingDict(). Limitation 2 : static cctx currently not compatible with multi-threading. Limitation 3 : static dctx is incompatible with legacy support.

ZSTD_initStaticCDict
ZSTD_initStaticCStream
ZSTD_initStaticDCtx
ZSTD_initStaticDDict
ZSTD_initStaticDStream
ZSTD_insertBlock
ZSTD_isError
ZSTD_isFrame

ZSTD_isFrame() : Tells if the content of buffer starts with a valid Frame Identifier. Note : Frame Identifier is 4 bytes. If size < 4, @return will always be 0. Note 2 : Legacy Frame Identifiers are considered valid only if Legacy Support is enabled. Note 3 : Skippable Frame Identifiers are considered valid.

ZSTD_maxCLevel
ZSTD_minCLevel
ZSTD_nextInputType
ZSTD_nextSrcSizeToDecompress
ZSTD_resetCStream

ZSTD_resetCStream() : start a new frame, using same parameters from previous frame. This is typically useful to skip dictionary loading stage, since it will re-use it in-place. Note that zcs must be init at least once before using ZSTD_resetCStream(). If pledgedSrcSize is not known at reset time, use macro ZSTD_CONTENTSIZE_UNKNOWN. If pledgedSrcSize > 0, its value must be correct, as it will be written in header, and controlled at the end. For the time being, pledgedSrcSize==0 is interpreted as "srcSize unknown" for compatibility with older programs, but it will change to mean "empty" in future version, so use macro ZSTD_CONTENTSIZE_UNKNOWN instead. @return : 0, or an error code (which can be tested using ZSTD_isError())

ZSTD_resetDStream
ZSTD_sizeof_CCtx

ZSTD_sizeof_*() : These functions give the current memory usage of selected object. Note that object memory usage can evolve (increase or decrease) over time.

ZSTD_sizeof_CDict
ZSTD_sizeof_CStream
ZSTD_sizeof_DCtx
ZSTD_sizeof_DDict
ZSTD_sizeof_DStream
ZSTD_toFlushNow

ZSTD_toFlushNow() : Tell how many bytes are ready to be flushed immediately. Useful for multithreading scenarios (nbWorkers >= 1). Probe the oldest active job, defined as oldest job not yet entirely flushed, and check its output buffer. @return : amount of data stored in oldest job and ready to be flushed immediately. if @return == 0, it means either :

ZSTD_versionNumber
ZSTD_versionString

Type Definitions

ZSTDMT_CCtx
ZSTD_CCtx

Explicit context

ZSTD_CCtx_params
ZSTD_CDict

Bulk processing dictionary API

ZSTD_CStream
ZSTD_DCtx
ZSTD_DDict
ZSTD_DStream
ZSTD_allocFunction

Custom memory allocation : These prototypes make it possible to pass your own allocation/free functions. ZSTD_customMem is provided at creation time, using ZSTD_create*_advanced() variants listed below. All allocation/free operations will be completed using these custom variants instead of regular <stdlib.h> ones.

ZSTD_freeFunction
ZSTD_inBuffer
ZSTD_outBuffer
wchar_t