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Merge pull request #725 from facebook/advancedAPI2

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New Advanced API
This commit is contained in:
Yann Collet
2017-06-23 09:50:47 -07:00
committed by GitHub
parent 0d0fea96bc 6122af9cf5
commit ef269c1b68
36 changed files with 3777 additions and 1798 deletions
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lib/zstd.h
+376 -72
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@@ -38,20 +38,21 @@ extern "C" {
/*******************************************************************************************************
Introduction
zstd, short for Zstandard, is a fast lossless compression algorithm, targeting real-time compression scenarios
at zlib-level and better compression ratios. The zstd compression library provides in-memory compression and
decompression functions. The library supports compression levels from 1 up to ZSTD_maxCLevel() which is 22.
zstd, short for Zstandard, is a fast lossless compression algorithm,
targeting real-time compression scenarios at zlib-level and better compression ratios.
The zstd compression library provides in-memory compression and decompression functions.
The library supports compression levels from 1 up to ZSTD_maxCLevel() which is currently 22.
Levels >= 20, labeled `--ultra`, should be used with caution, as they require more memory.
Compression can be done in:
- a single step (described as Simple API)
- a single step, reusing a context (described as Explicit memory management)
- unbounded multiple steps (described as Streaming compression)
The compression ratio achievable on small data can be highly improved using compression with a dictionary in:
The compression ratio achievable on small data can be highly improved using a dictionary in:
- a single step (described as Simple dictionary API)
- a single step, reusing a dictionary (described as Fast dictionary API)
Advanced experimental functions can be accessed using #define ZSTD_STATIC_LINKING_ONLY before including zstd.h.
These APIs shall never be used with a dynamic library.
Advanced experimental APIs shall never be used with a dynamic library.
They are not "stable", their definition may change in the future. Only static linking is allowed.
*********************************************************************************************************/
@@ -61,13 +62,13 @@ extern "C" {
#define ZSTD_VERSION_RELEASE 0
#define ZSTD_VERSION_NUMBER (ZSTD_VERSION_MAJOR *100*100 + ZSTD_VERSION_MINOR *100 + ZSTD_VERSION_RELEASE)
ZSTDLIB_API unsigned ZSTD_versionNumber(void); /**< to be used when checking dll version */
ZSTDLIB_API unsigned ZSTD_versionNumber(void); /**< useful to check dll version */
#define ZSTD_LIB_VERSION ZSTD_VERSION_MAJOR.ZSTD_VERSION_MINOR.ZSTD_VERSION_RELEASE
#define ZSTD_QUOTE(str) #str
#define ZSTD_EXPAND_AND_QUOTE(str) ZSTD_QUOTE(str)
#define ZSTD_VERSION_STRING ZSTD_EXPAND_AND_QUOTE(ZSTD_LIB_VERSION)
ZSTDLIB_API const char* ZSTD_versionString(void);
ZSTDLIB_API const char* ZSTD_versionString(void); /* >= v1.3.0 */
/***************************************
@@ -84,7 +85,7 @@ ZSTDLIB_API size_t ZSTD_compress( void* dst, size_t dstCapacity,
/*! ZSTD_decompress() :
* `compressedSize` : must be the _exact_ size of some number of compressed and/or skippable frames.
* `dstCapacity` is an upper bound of originalSize.
* `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()). */
@@ -92,21 +93,17 @@ ZSTDLIB_API size_t ZSTD_decompress( void* dst, size_t dstCapacity,
const void* src, size_t compressedSize);
/*! ZSTD_getDecompressedSize() :
* NOTE: This function is planned to be obsolete, in favour of ZSTD_getFrameContentSize.
* ZSTD_getFrameContentSize functions the same way, returning the decompressed size of a single
* frame, but distinguishes empty frames from frames with an unknown size, or errors.
*
* Additionally, ZSTD_findDecompressedSize can be used instead. It can handle multiple
* concatenated frames in one buffer, and so is more general.
* As a result however, it requires more computation and entire frames to be passed to it,
* as opposed to ZSTD_getFrameContentSize which requires only a single frame's header.
* NOTE: This function is planned to be obsolete, in favor of ZSTD_getFrameContentSize().
* ZSTD_getFrameContentSize() works the same way,
* returning the decompressed size of a single frame,
* but distinguishes empty frames from frames with an unknown size, or errors.
*
* 'src' is the start of a zstd compressed frame.
* @return : content size to be decompressed, as a 64-bits value _if known_, 0 otherwise.
* note 1 : decompressed size is an optional field, that may not be present, especially in streaming mode.
* note 1 : decompressed size is an optional field, it may not be present, typically in streaming mode.
* When `return==0`, data to decompress could be any size.
* In which case, it's necessary to use streaming mode to decompress data.
* Optionally, application can still use ZSTD_decompress() while relying on implied limits.
* Optionally, application can use ZSTD_decompress() while relying on implied limits.
* (For example, data may be necessarily cut into blocks <= 16 KB).
* note 2 : decompressed size is always present when compression is done with ZSTD_compress()
* note 3 : decompressed size can be very large (64-bits value),
@@ -115,7 +112,7 @@ ZSTDLIB_API size_t ZSTD_decompress( void* dst, size_t dstCapacity,
* note 4 : If source is untrusted, decompressed size could be wrong or intentionally modified.
* Always ensure result fits within application's authorized limits.
* Each application can set its own limits.
* note 5 : when `return==0`, if precise failure cause is needed, use ZSTD_getFrameParams() to know more. */
* note 5 : when `return==0`, if precise failure cause is needed, use ZSTD_getFrameHeader() to know more. */
ZSTDLIB_API unsigned long long ZSTD_getDecompressedSize(const void* src, size_t srcSize);
@@ -140,29 +137,35 @@ ZSTDLIB_API size_t ZSTD_freeCCtx(ZSTD_CCtx* cctx);
/*! ZSTD_compressCCtx() :
* Same as ZSTD_compress(), requires an allocated ZSTD_CCtx (see ZSTD_createCCtx()). */
ZSTDLIB_API size_t ZSTD_compressCCtx(ZSTD_CCtx* ctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize, int compressionLevel);
ZSTDLIB_API size_t ZSTD_compressCCtx(ZSTD_CCtx* ctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
int compressionLevel);
/*= Decompression context
* When decompressing many times,
* it is recommended to allocate a context just once, and re-use it for each successive compression operation.
* it is recommended to allocate a context only once,
* and re-use it for each successive compression operation.
* This will make workload friendlier for system's memory.
* Use one context per thread for parallel execution in multi-threaded environments. */
* Use one context per thread for parallel execution. */
typedef struct ZSTD_DCtx_s ZSTD_DCtx;
ZSTDLIB_API ZSTD_DCtx* ZSTD_createDCtx(void);
ZSTDLIB_API size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
/*! ZSTD_decompressDCtx() :
* Same as ZSTD_decompress(), requires an allocated ZSTD_DCtx (see ZSTD_createDCtx()). */
ZSTDLIB_API size_t ZSTD_decompressDCtx(ZSTD_DCtx* ctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
* Same as ZSTD_decompress(), requires an allocated ZSTD_DCtx (see ZSTD_createDCtx()) */
ZSTDLIB_API size_t ZSTD_decompressDCtx(ZSTD_DCtx* ctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize);
/**************************
* Simple dictionary API
***************************/
/*! ZSTD_compress_usingDict() :
* Compression using a predefined Dictionary (see dictBuilder/zdict.h).
* Note : This function loads the dictionary, resulting in significant startup delay.
* Note : When `dict == NULL || dictSize < 8` no dictionary is used. */
* Compression using a predefined Dictionary (see dictBuilder/zdict.h).
* Note : This function loads the dictionary, resulting in significant startup delay.
* Note : When `dict == NULL || dictSize < 8` no dictionary is used. */
ZSTDLIB_API size_t ZSTD_compress_usingDict(ZSTD_CCtx* ctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
@@ -170,30 +173,31 @@ ZSTDLIB_API size_t ZSTD_compress_usingDict(ZSTD_CCtx* ctx,
int compressionLevel);
/*! ZSTD_decompress_usingDict() :
* Decompression using a predefined Dictionary (see dictBuilder/zdict.h).
* Dictionary must be identical to the one used during compression.
* Note : This function loads the dictionary, resulting in significant startup delay.
* Note : When `dict == NULL || dictSize < 8` no dictionary is used. */
* Decompression using a predefined Dictionary (see dictBuilder/zdict.h).
* Dictionary must be identical to the one used during compression.
* Note : This function loads the dictionary, resulting in significant startup delay.
* Note : When `dict == NULL || dictSize < 8` no dictionary is used. */
ZSTDLIB_API size_t ZSTD_decompress_usingDict(ZSTD_DCtx* dctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
const void* dict,size_t dictSize);
/****************************
* Fast dictionary API
****************************/
/**********************************
* Bulk processing dictionary API
*********************************/
typedef struct ZSTD_CDict_s ZSTD_CDict;
/*! ZSTD_createCDict() :
* When compressing multiple messages / blocks with the same dictionary, it's recommended to load it just once.
* ZSTD_createCDict() will create a digested dictionary, ready to start future compression operations without startup delay.
* ZSTD_CDict can be created once and used by multiple threads concurrently, as its usage is read-only.
* `dictBuffer` can be released after ZSTD_CDict creation, as its content is copied within CDict */
ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict(const void* dictBuffer, size_t dictSize, int compressionLevel);
* When compressing multiple messages / blocks with the same dictionary, it's recommended to load it just once.
* ZSTD_createCDict() will create a digested dictionary, ready to start future compression operations without startup delay.
* 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, since its content is copied within CDict */
ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict(const void* dictBuffer, size_t dictSize,
int compressionLevel);
/*! ZSTD_freeCDict() :
* Function frees memory allocated by ZSTD_createCDict(). */
* Function frees memory allocated by ZSTD_createCDict(). */
ZSTDLIB_API size_t ZSTD_freeCDict(ZSTD_CDict* CDict);
/*! ZSTD_compress_usingCDict() :
@@ -210,17 +214,17 @@ ZSTDLIB_API size_t ZSTD_compress_usingCDict(ZSTD_CCtx* cctx,
typedef struct ZSTD_DDict_s ZSTD_DDict;
/*! 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 */
* 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 */
ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict(const void* dictBuffer, size_t dictSize);
/*! ZSTD_freeDDict() :
* Function frees memory allocated with ZSTD_createDDict() */
* Function frees memory allocated with ZSTD_createDDict() */
ZSTDLIB_API size_t ZSTD_freeDDict(ZSTD_DDict* ddict);
/*! ZSTD_decompress_usingDDict() :
* Decompression using a digested Dictionary.
* Faster startup than ZSTD_decompress_usingDict(), recommended when same dictionary is used multiple times. */
* Decompression using a digested Dictionary.
* Faster startup than ZSTD_decompress_usingDict(), recommended when same dictionary is used multiple times. */
ZSTDLIB_API size_t ZSTD_decompress_usingDDict(ZSTD_DCtx* dctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
@@ -277,15 +281,17 @@ typedef struct ZSTD_outBuffer_s {
* ZSTD_endStream() instructs to finish a frame.
* It will perform a flush and write frame epilogue.
* The epilogue is required for decoders to consider a frame completed.
* Similar to ZSTD_flushStream(), it may not be able to flush the full content if `output->size` is too small.
* ZSTD_endStream() may not be able to flush full data if `output->size` is too small.
* In which case, call again ZSTD_endStream() to complete the flush.
* @return : nb of bytes still present within internal buffer (0 if it's empty, hence compression completed)
* @return : 0 if frame fully completed and fully flushed,
or >0 if some data is still present within internal buffer
(value is minimum size estimation for remaining data to flush, but it could be more)
* or an error code, which can be tested using ZSTD_isError().
*
* *******************************************************************/
typedef ZSTD_CCtx ZSTD_CStream; /**< CCtx and CStream are effectively same object */
/* Continue due distinghish them for compatibility with versions <= v1.2.0 */
typedef ZSTD_CCtx ZSTD_CStream; /**< CCtx and CStream are now effectively same object (>= v1.3.0) */
/* But continue to distinguish them for compatibility with versions <= v1.2.0 */
/*===== ZSTD_CStream management functions =====*/
ZSTDLIB_API ZSTD_CStream* ZSTD_createCStream(void);
ZSTDLIB_API size_t ZSTD_freeCStream(ZSTD_CStream* zcs);
@@ -323,7 +329,8 @@ ZSTDLIB_API size_t ZSTD_CStreamOutSize(void); /**< recommended size for output
* The return value is a suggested next input size (a hint to improve latency) that will never load more than the current frame.
* *******************************************************************************/
typedef struct ZSTD_DStream_s ZSTD_DStream;
typedef ZSTD_DCtx ZSTD_DStream; /**< DCtx and DStream are now effectively same object (>= v1.3.0) */
/* But continue to distinguish them for compatibility with versions <= v1.2.0 */
/*===== ZSTD_DStream management functions =====*/
ZSTDLIB_API ZSTD_DStream* ZSTD_createDStream(void);
ZSTDLIB_API size_t ZSTD_freeDStream(ZSTD_DStream* zds);
@@ -338,8 +345,6 @@ ZSTDLIB_API size_t ZSTD_DStreamOutSize(void); /*!< recommended size for output
#endif /* ZSTD_H_235446 */
#if defined(ZSTD_STATIC_LINKING_ONLY) && !defined(ZSTD_H_ZSTD_STATIC_LINKING_ONLY)
#define ZSTD_H_ZSTD_STATIC_LINKING_ONLY
/****************************************************************************************
* START OF ADVANCED AND EXPERIMENTAL FUNCTIONS
@@ -349,6 +354,9 @@ ZSTDLIB_API size_t ZSTD_DStreamOutSize(void); /*!< recommended size for output
* Use them only in association with static linking.
* ***************************************************************************************/
#if defined(ZSTD_STATIC_LINKING_ONLY) && !defined(ZSTD_H_ZSTD_STATIC_LINKING_ONLY)
#define ZSTD_H_ZSTD_STATIC_LINKING_ONLY
/* --- Constants ---*/
#define ZSTD_MAGICNUMBER 0xFD2FB528 /* >= v0.8.0 */
#define ZSTD_MAGIC_SKIPPABLE_START 0x184D2A50U
@@ -378,7 +386,8 @@ static const size_t ZSTD_skippableHeaderSize = 8; /* magic number + skippable f
/*--- Advanced types ---*/
typedef enum { ZSTD_fast, ZSTD_dfast, ZSTD_greedy, ZSTD_lazy, ZSTD_lazy2, ZSTD_btlazy2, ZSTD_btopt, ZSTD_btultra } ZSTD_strategy; /* from faster to stronger */
typedef enum { ZSTD_fast=1, ZSTD_dfast, ZSTD_greedy, ZSTD_lazy, ZSTD_lazy2,
ZSTD_btlazy2, ZSTD_btopt, ZSTD_btultra } ZSTD_strategy; /* from faster to stronger */
typedef struct {
unsigned windowLog; /**< largest match distance : larger == more compression, more memory needed during decompression */
@@ -412,6 +421,9 @@ typedef struct {
typedef void* (*ZSTD_allocFunction) (void* opaque, size_t size);
typedef void (*ZSTD_freeFunction) (void* opaque, void* address);
typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; void* opaque; } ZSTD_customMem;
/* use this constant to defer to stdlib's functions */
static const ZSTD_customMem ZSTD_defaultCMem = { NULL, NULL, NULL };
/***************************************
* Frame size functions
@@ -485,21 +497,22 @@ ZSTDLIB_API size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict);
* These functions make it possible to estimate memory usage
* of a future target object, before its allocation,
* given a set of parameters, which vary depending on target object.
* The objective is to guide decision before allocation. */
* The objective is to guide decision before allocation.
* Note : CCtx estimation is only correct for single-threaded compression */
ZSTDLIB_API size_t ZSTD_estimateCCtxSize(ZSTD_compressionParameters cParams);
ZSTDLIB_API size_t ZSTD_estimateDCtxSize(void);
/*! ZSTD_estimate?StreamSize() :
* Note : if streaming is init with function ZSTD_init?Stream_usingDict(),
* an internal ?Dict will be created, which size is not estimated.
* In this case, get additional size by using ZSTD_estimate?DictSize */
* an internal ?Dict will be created, which size is not estimated here.
* In this case, get total size by adding ZSTD_estimate?DictSize */
ZSTDLIB_API size_t ZSTD_estimateCStreamSize(ZSTD_compressionParameters cParams);
ZSTDLIB_API size_t ZSTD_estimateDStreamSize(ZSTD_frameHeader fHeader);
/*! ZSTD_estimate?DictSize() :
* Note : if dictionary is created "byReference", reduce estimation by dictSize */
ZSTDLIB_API size_t ZSTD_estimateCDictSize(ZSTD_compressionParameters cParams, size_t dictSize);
ZSTDLIB_API size_t ZSTD_estimateDDictSize(size_t dictSize);
* Note : dictionary created "byReference" are smaller */
ZSTDLIB_API size_t ZSTD_estimateCDictSize(ZSTD_compressionParameters cParams, size_t dictSize, unsigned byReference);
ZSTDLIB_API size_t ZSTD_estimateDDictSize(size_t dictSize, unsigned byReference);
/***************************************
@@ -509,6 +522,25 @@ ZSTDLIB_API size_t ZSTD_estimateDDictSize(size_t dictSize);
* Create a ZSTD compression context using external alloc and free functions */
ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem);
/*! ZSTD_initStaticCCtx() : initialize a fixed-size zstd compression context
* workspace: The memory area to emplace the context into.
* Provided pointer must 8-bytes aligned.
* It must outlive context usage.
* workspaceSize: Use ZSTD_estimateCCtxSize() or ZSTD_estimateCStreamSize()
* to determine how large workspace must be to support scenario.
* @return : pointer to ZSTD_CCtx*, or NULL if error (size too small)
* Note : zstd will never resize nor malloc() when using a static cctx.
* If it needs more memory than available, it will simply error out.
* Note 2 : there is no corresponding "free" function.
* Since workspace was allocated externally, it must be freed externally too.
* Limitation 1 : currently not compatible with internal CDict creation, such as
* ZSTD_CCtx_loadDictionary() or ZSTD_initCStream_usingDict().
* Limitation 2 : currently not compatible with multi-threading
*/
ZSTDLIB_API ZSTD_CCtx* ZSTD_initStaticCCtx(void* workspace, size_t workspaceSize);
/* !!! To be deprecated !!! */
typedef enum {
ZSTD_p_forceWindow, /* Force back-references to remain < windowSize, even when referencing Dictionary content (default:0) */
ZSTD_p_forceRawDict /* Force loading dictionary in "content-only" mode (no header analysis) */
@@ -518,17 +550,40 @@ typedef enum {
* @result : 0, or an error code (which can be tested with ZSTD_isError()) */
ZSTDLIB_API size_t ZSTD_setCCtxParameter(ZSTD_CCtx* cctx, ZSTD_CCtxParameter param, unsigned value);
/*! ZSTD_createCDict_byReference() :
* Create a digested dictionary for compression
* Dictionary content is simply referenced, and therefore stays in dictBuffer.
* It is important that dictBuffer outlives CDict, it must remain read accessible throughout the lifetime of CDict */
ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_byReference(const void* dictBuffer, size_t dictSize, int compressionLevel);
typedef enum { ZSTD_dm_auto=0, ZSTD_dm_rawContent, ZSTD_dm_fullDict } ZSTD_dictMode_e;
/*! ZSTD_createCDict_advanced() :
* Create a ZSTD_CDict using external alloc and free, and customized compression parameters */
ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_advanced(const void* dict, size_t dictSize, unsigned byReference,
ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_advanced(const void* dict, size_t dictSize,
unsigned byReference, ZSTD_dictMode_e dictMode,
ZSTD_compressionParameters cParams, ZSTD_customMem customMem);
/*! ZSTD_initStaticCDict_advanced() :
* Generate a digested dictionary in provided memory area.
* workspace: The memory area to emplace the dictionary into.
* Provided pointer must 8-bytes aligned.
* It must outlive dictionary usage.
* workspaceSize: Use ZSTD_estimateCDictSize()
* to determine how large workspace must be.
* cParams : use ZSTD_getCParams() to transform a compression level
* into its relevants cParams.
* @return : pointer to ZSTD_CDict*, or NULL if error (size too small)
* Note : there is no corresponding "free" function.
* Since workspace was allocated externally, it must be freed externally.
*/
ZSTDLIB_API ZSTD_CDict* ZSTD_initStaticCDict(
void* workspace, size_t workspaceSize,
const void* dict, size_t dictSize,
unsigned byReference, ZSTD_dictMode_e dictMode,
ZSTD_compressionParameters cParams);
/*! ZSTD_getCParams() :
* @return ZSTD_compressionParameters structure for a selected compression level and estimated srcSize.
* `estimatedSrcSize` value is optional, select 0 if not known */
@@ -544,8 +599,8 @@ ZSTDLIB_API ZSTD_parameters ZSTD_getParams(int compressionLevel, unsigned long l
ZSTDLIB_API size_t ZSTD_checkCParams(ZSTD_compressionParameters params);
/*! ZSTD_adjustCParams() :
* optimize params for a given `srcSize` and `dictSize`.
* both values are optional, select `0` if unknown. */
* optimize params for a given `srcSize` and `dictSize`.
* both values are optional, select `0` if unknown. */
ZSTDLIB_API ZSTD_compressionParameters ZSTD_adjustCParams(ZSTD_compressionParameters cPar, unsigned long long srcSize, size_t dictSize);
/*! ZSTD_compress_advanced() :
@@ -577,10 +632,28 @@ ZSTDLIB_API unsigned ZSTD_isFrame(const void* buffer, size_t size);
* Create a ZSTD decompression context using external alloc and free functions */
ZSTDLIB_API ZSTD_DCtx* ZSTD_createDCtx_advanced(ZSTD_customMem customMem);
/*! ZSTD_initStaticDCtx() : initialize a fixed-size zstd decompression context
* workspace: The memory area to emplace the context into.
* Provided pointer must 8-bytes aligned.
* It must outlive context usage.
* workspaceSize: Use ZSTD_estimateDCtxSize() or ZSTD_estimateDStreamSize()
* to determine how large workspace must be to support scenario.
* @return : pointer to ZSTD_DCtx*, or NULL if error (size too small)
* Note : zstd will never resize nor malloc() when using a static dctx.
* If it needs more memory than available, it will simply error out.
* Note 2 : static dctx is incompatible with legacy support
* Note 3 : there is no corresponding "free" function.
* Since workspace was allocated externally, it must be freed externally.
* Limitation : currently not compatible with internal DDict creation,
* such as ZSTD_initDStream_usingDict().
*/
ZSTDLIB_API ZSTD_DCtx* ZSTD_initStaticDCtx(void* workspace, size_t workspaceSize);
/*! ZSTD_createDDict_byReference() :
* Create a digested dictionary, ready to start decompression operation without startup delay.
* Dictionary content is simply referenced, and therefore stays in dictBuffer.
* It is important that dictBuffer outlives DDict, it must remain read accessible throughout the lifetime of DDict */
* 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 */
ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict_byReference(const void* dictBuffer, size_t dictSize);
/*! ZSTD_createDDict_advanced() :
@@ -588,6 +661,21 @@ ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict_byReference(const void* dictBuffer, siz
ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict_advanced(const void* dict, size_t dictSize,
unsigned byReference, ZSTD_customMem customMem);
/*! ZSTD_initStaticDDict() :
* Generate a digested dictionary in provided memory area.
* workspace: The memory area to emplace the dictionary into.
* Provided pointer must 8-bytes aligned.
* It must outlive dictionary usage.
* workspaceSize: Use ZSTD_estimateDDictSize()
* to determine how large workspace must be.
* @return : pointer to ZSTD_DDict*, or NULL if error (size too small)
* Note : there is no corresponding "free" function.
* Since workspace was allocated externally, it must be freed externally.
*/
ZSTDLIB_API ZSTD_DDict* ZSTD_initStaticDDict(void* workspace, size_t workspaceSize,
const void* dict, size_t dictSize,
unsigned byReference);
/*! ZSTD_getDictID_fromDict() :
* Provides the dictID stored within dictionary.
* if @return == 0, the dictionary is not conformant with Zstandard specification.
@@ -609,7 +697,7 @@ ZSTDLIB_API unsigned ZSTD_getDictID_fromDDict(const ZSTD_DDict* ddict);
* Note : this use case also happens when using a non-conformant dictionary.
* - `srcSize` is too small, and as a result, the frame header could not be decoded (only possible if `srcSize < ZSTD_FRAMEHEADERSIZE_MAX`).
* - This is not a Zstandard frame.
* When identifying the exact failure cause, it's possible to use ZSTD_getFrameParams(), which will provide a more precise error code. */
* When identifying the exact failure cause, it's possible to use ZSTD_getFrameHeader(), which will provide a more precise error code. */
ZSTDLIB_API unsigned ZSTD_getDictID_fromFrame(const void* src, size_t srcSize);
@@ -620,11 +708,11 @@ ZSTDLIB_API unsigned ZSTD_getDictID_fromFrame(const void* src, size_t srcSize);
/*===== Advanced Streaming compression functions =====*/
ZSTDLIB_API ZSTD_CStream* ZSTD_createCStream_advanced(ZSTD_customMem customMem);
ZSTDLIB_API size_t ZSTD_initCStream_srcSize(ZSTD_CStream* zcs, int compressionLevel, unsigned long long pledgedSrcSize); /**< pledgedSrcSize must be correct, a size of 0 means unknown. for a frame size of 0 use initCStream_advanced */
ZSTDLIB_API size_t ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, const void* dict, size_t dictSize, int compressionLevel); /**< note: a dict will not be used if dict == NULL or dictSize < 8. This result in the creation of an internal CDict */
ZSTDLIB_API size_t ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, const void* dict, size_t dictSize, int compressionLevel); /**< creates of an internal CDict (incompatible with static CCtx), except if dict == NULL or dictSize < 8, in which case no dict is used. */
ZSTDLIB_API size_t ZSTD_initCStream_advanced(ZSTD_CStream* zcs, const void* dict, size_t dictSize,
ZSTD_parameters params, unsigned long long pledgedSrcSize); /**< pledgedSrcSize is optional and can be 0 (meaning unknown). note: if the contentSizeFlag is set, pledgedSrcSize == 0 means the source size is actually 0 */
ZSTDLIB_API size_t ZSTD_initCStream_usingCDict(ZSTD_CStream* zcs, const ZSTD_CDict* cdict); /**< note : cdict will just be referenced, and must outlive compression session */
ZSTDLIB_API size_t ZSTD_initCStream_usingCDict_advanced(ZSTD_CStream* zcs, const ZSTD_CDict* cdict, unsigned long long pledgedSrcSize, ZSTD_frameParameters fParams); /**< same as ZSTD_initCStream_usingCDict(), with control over frame parameters */
ZSTDLIB_API size_t ZSTD_initCStream_usingCDict_advanced(ZSTD_CStream* zcs, const ZSTD_CDict* cdict, ZSTD_frameParameters fParams, unsigned long long pledgedSrcSize); /**< same as ZSTD_initCStream_usingCDict(), with control over frame parameters */
/*! ZSTD_resetCStream() :
* start a new compression job, using same parameters from previous job.
@@ -704,7 +792,7 @@ ZSTDLIB_API size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t dstCapaci
Use ZSTD_createDCtx() / ZSTD_freeDCtx() to manage it.
A ZSTD_DCtx object can be re-used multiple times.
First typical operation is to retrieve frame parameters, using ZSTD_getFrameParams().
First typical operation is to retrieve frame parameters, using ZSTD_getFrameHeader().
It fills a ZSTD_frameParams structure which provide important information to correctly decode the frame,
such as the minimum rolling buffer size to allocate to decompress data (`windowSize`),
and the dictionary ID used.
@@ -751,7 +839,7 @@ ZSTDLIB_API size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t dstCapaci
b) Frame Size - 4 Bytes, Little endian format, unsigned 32-bits
c) Frame Content - any content (User Data) of length equal to Frame Size
For skippable frames ZSTD_decompressContinue() always returns 0.
For skippable frames ZSTD_getFrameParams() returns fparamsPtr->windowLog==0 what means that a frame is skippable.
For skippable frames ZSTD_getFrameHeader() returns fparamsPtr->windowLog==0 what means that a frame is skippable.
Note : If fparamsPtr->frameContentSize==0, it is ambiguous: the frame might actually be a Zstd encoded frame with no content.
For purposes of decompression, it is valid in both cases to skip the frame using
ZSTD_findFrameCompressedSize to find its size in bytes.
@@ -770,6 +858,221 @@ ZSTDLIB_API size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t ds
typedef enum { ZSTDnit_frameHeader, ZSTDnit_blockHeader, ZSTDnit_block, ZSTDnit_lastBlock, ZSTDnit_checksum, ZSTDnit_skippableFrame } ZSTD_nextInputType_e;
ZSTDLIB_API ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx* dctx);
/*=== New advanced API (experimental, and compression only) ===*/
/* notes on API design :
* In this proposal, parameters are pushed one by one into an existing CCtx,
* and then applied on all subsequent compression jobs.
* When no parameter is ever provided, CCtx is created with compression level ZSTD_CLEVEL_DEFAULT.
*
* This API is intended to replace all others experimental API.
* It can basically do all other use cases, and even new ones.
* It stands a good chance to become "stable",
* after a reasonable testing period.
*/
/* note on naming convention :
* Initially, the API favored names like ZSTD_setCCtxParameter() .
* In this proposal, convention is changed towards ZSTD_CCtx_setParameter() .
* The main driver is that it identifies more clearly the target object type.
* It feels clearer in light of potential variants :
* ZSTD_CDict_setParameter() (rather than ZSTD_setCDictParameter())
* ZSTD_DCtx_setParameter() (rather than ZSTD_setDCtxParameter() )
* Left variant feels easier to distinguish.
*/
/* note on enum design :
* All enum will be manually set to explicit values before reaching "stable API" status */
typedef enum {
/* compression parameters */
ZSTD_p_compressionLevel=100, /* Update all compression parameters according to pre-defined cLevel table
* Default level is ZSTD_CLEVEL_DEFAULT==3.
* Special: value 0 means "do not change cLevel". */
ZSTD_p_windowLog, /* Maximum allowed back-reference distance, expressed as power of 2.
* Must be clamped between ZSTD_WINDOWLOG_MIN and ZSTD_WINDOWLOG_MAX.
* Special: value 0 means "do not change windowLog". */
ZSTD_p_hashLog, /* Size of the probe table, as a power of 2.
* Resulting table size is (1 << (hashLog+2)).
* Must be clamped between ZSTD_HASHLOG_MIN and ZSTD_HASHLOG_MAX.
* Larger tables improve compression ratio of strategies <= dFast,
* and improve speed of strategies > dFast.
* Special: value 0 means "do not change hashLog". */
ZSTD_p_chainLog, /* Size of the full-search table, as a power of 2.
* Resulting table size is (1 << (chainLog+2)).
* Larger tables result in better and slower compression.
* This parameter is useless when using "fast" strategy.
* Special: value 0 means "do not change chainLog". */
ZSTD_p_searchLog, /* Number of search attempts, as a power of 2.
* More attempts result in better and slower compression.
* This parameter is useless when using "fast" and "dFast" strategies.
* Special: value 0 means "do not change searchLog". */
ZSTD_p_minMatch, /* Minimum size of searched matches (note : repCode matches can be smaller).
* Larger values make faster compression and decompression, but decrease ratio.
* Must be clamped between ZSTD_SEARCHLENGTH_MIN and ZSTD_SEARCHLENGTH_MAX.
* Note that currently, for all strategies < btopt, effective minimum is 4.
* Note that currently, for all strategies > fast, effective maximum is 6.
* Special: value 0 means "do not change minMatchLength". */
ZSTD_p_targetLength, /* Only useful for strategies >= btopt.
* Length of Match considered "good enough" to stop search.
* Larger values make compression stronger and slower.
* Special: value 0 means "do not change targetLength". */
ZSTD_p_compressionStrategy, /* See ZSTD_strategy enum definition.
* Cast selected strategy as unsigned for ZSTD_CCtx_setParameter() compatibility.
* The higher the value of selected strategy, the more complex it is,
* resulting in stronger and slower compression.
* Special: value 0 means "do not change strategy". */
#if 0
ZSTD_p_windowSize, /* Maximum allowed back-reference distance.
* Can be set to a more precise value than windowLog.
* Will be transparently reduced to closest possible inferior value
* (see Zstandard compression format) */
/* Not ready yet ! */
#endif
/* frame parameters */
ZSTD_p_contentSizeFlag=200, /* Content size is written into frame header _whenever known_ (default:1) */
ZSTD_p_checksumFlag, /* A 32-bits checksum of content is written at end of frame (default:0) */
ZSTD_p_dictIDFlag, /* When applicable, dictID of dictionary is provided in frame header (default:1) */
/* dictionary parameters */
ZSTD_p_refDictContent=300, /* Content of dictionary content will be referenced, instead of copied (default:0).
* This avoids duplicating dictionary content.
* But it also requires that dictionary buffer outlives its users */
/* Not ready yet ! <=================================== */
ZSTD_p_dictMode, /* Select how dictionary must be interpreted. Value must be from type ZSTD_dictMode_e.
* default : 0==auto : dictionary will be "full" if it respects specification, otherwise it will be "rawContent" */
/* multi-threading parameters */
ZSTD_p_nbThreads=400, /* Select how many threads a compression job can spawn (default:1)
* More threads improve speed, but also increase memory usage.
* Can only receive a value > 1 if ZSTD_MULTITHREAD is enabled.
* Special: value 0 means "do not change nbThreads" */
ZSTD_p_jobSize, /* Size of a compression job. Each compression job is completed in parallel.
* 0 means default, which is dynamically determined based on compression parameters.
* Job size must be a minimum of overlapSize, or 1 KB, whichever is largest
* The minimum size is automatically and transparently enforced */
ZSTD_p_overlapSizeLog, /* Size of previous input reloaded at the beginning of each job.
* 0 => no overlap, 6(default) => use 1/8th of windowSize, >=9 => use full windowSize */
/* advanced parameters - may not remain available after API update */
ZSTD_p_forceMaxWindow=1100, /* Force back-references to remain < windowSize,
* even when referencing into Dictionary content.
* default : 0 when using a CDict, 1 when using a Prefix */
} ZSTD_cParameter;
/*! ZSTD_CCtx_setParameter() :
* Set one compression parameter, selected by enum ZSTD_cParameter.
* Note : when `value` is an enum, cast it to unsigned for proper type checking.
* @result : 0, or an error code (which can be tested with ZSTD_isError()). */
ZSTDLIB_API size_t ZSTD_CCtx_setParameter(ZSTD_CCtx* cctx, ZSTD_cParameter param, unsigned value);
/*! ZSTD_CCtx_setPledgedSrcSize() :
* Total input data size to be compressed as a single frame.
* This value will be controlled at the end, and result in error if not respected.
* @result : 0, or an error code (which can be tested with ZSTD_isError()).
* Note 1 : 0 means zero, empty.
* In order to mean "unknown content size", pass constant ZSTD_CONTENTSIZE_UNKNOWN.
* Note that ZSTD_CONTENTSIZE_UNKNOWN is default value for new compression jobs.
* Note 2 : If all data is provided and consumed in a single round,
* this value is overriden by srcSize instead. */
ZSTDLIB_API size_t ZSTD_CCtx_setPledgedSrcSize(ZSTD_CCtx* cctx, unsigned long long pledgedSrcSize);
/*! ZSTD_CCtx_loadDictionary() :
* Create an internal CDict from dict buffer.
* Decompression will have to use same buffer.
* @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 : Dictionary content will be copied internally,
* except if ZSTD_p_refDictContent is set.
* Note 2 : Loading a dictionary involves building tables, which are dependent on compression parameters.
* For this reason, compression parameters cannot be changed anymore after loading a dictionary.
* It's also a CPU-heavy operation, with non-negligible impact on latency.
* Note 3 : Dictionary will be used for all future compression jobs.
* To return to "no-dictionary" situation, load a NULL dictionary */
ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary(ZSTD_CCtx* cctx, const void* dict, size_t dictSize);
/*! ZSTD_CCtx_refCDict() :
* Ref a prepared dictionary, to be used for all next compression jobs.
* 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 compression jobs using same CCtx.
* @result : 0, or an error code (which can be tested with ZSTD_isError()).
* Special : adding a NULL CDict means "return to no-dictionary mode".
* Note 1 : Currently, only one dictionary can be managed.
* Adding a new dictionary effectively "discards" any previous one.
* Note 2 : CDict is just referenced, its lifetime must outlive CCtx.
*/
ZSTDLIB_API size_t ZSTD_CCtx_refCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict);
/*! ZSTD_CCtx_refPrefix() :
* Reference a prefix (content-only dictionary) to bootstrap next compression job.
* Decompression will have to use same prefix.
* Prefix is only used once. Tables are discarded at end of compression job.
* If there is a need to use same prefix multiple times, consider embedding it into a ZSTD_CDict.
* @result : 0, or an error code (which can be tested with ZSTD_isError()).
* Special : Adding a NULL (or 0-size) dictionary invalidates any previous prefix, meaning "return to no-dictionary mode".
* Note 1 : Prefix buffer is referenced. It must outlive compression job.
* Note 2 : Referencing a prefix involves building tables, which are dependent on compression parameters.
* It's a CPU-heavy operation, with non-negligible impact on latency. */
ZSTDLIB_API size_t ZSTD_CCtx_refPrefix(ZSTD_CCtx* cctx, const void* prefix, size_t prefixSize); /* Not ready yet ! <===================================== */
typedef enum {
ZSTD_e_continue=0, /* collect more data, encoder transparently decides when to output result, for optimal conditions */
ZSTD_e_flush, /* flush any data provided so far - frame will continue, future data can still reference previous data for better compression */
ZSTD_e_end /* flush any remaining data and ends current frame. Any future compression starts a new frame. */
} ZSTD_EndDirective;
/*! ZSTD_compress_generic() :
* Behave about the same as ZSTD_compressStream. To note :
* - Compression parameters are pushed into CCtx before starting compression, using ZSTD_CCtx_setParameter()
* - Compression parameters cannot be changed once compression is started.
* - *dstPos must be <= dstCapacity, *srcPos must be <= srcSize
* - *dspPos and *srcPos will be updated. They are guaranteed to remain below their respective limit.
* - @return provides the minimum amount of data still to flush from internal buffers
* or an error code, which can be tested using ZSTD_isError().
* if @return != 0, flush is not fully completed, there is some data left within internal buffers.
* - after a ZSTD_e_end directive, if internal buffer is not fully flushed,
* only ZSTD_e_end or ZSTD_e_flush operations are allowed.
* It is necessary to fully flush internal buffers
* before starting a new compression job, or changing compression parameters.
*/
ZSTDLIB_API size_t ZSTD_compress_generic (ZSTD_CCtx* cctx,
ZSTD_outBuffer* output,
ZSTD_inBuffer* input,
ZSTD_EndDirective endOp);
/*! ZSTD_CCtx_reset() :
* Return a CCtx to clean state.
* Useful after an error, or to interrupt an ongoing compression job and start a new one.
* Any internal data not yet flushed is cancelled.
* Dictionary (if any) is dropped.
* It's possible to modify compression parameters after a reset.
*/
ZSTDLIB_API void ZSTD_CCtx_reset(ZSTD_CCtx* cctx); /* Not ready yet ! */
/*! ZSTD_compress_generic_simpleArgs() :
* Same as ZSTD_compress_generic(),
* but using only integral types as arguments.
* Argument list is larger and less expressive than ZSTD_{in,out}Buffer,
* but can be helpful for binders from dynamic languages
* which have troubles handling structures containing memory pointers.
*/
size_t ZSTD_compress_generic_simpleArgs (
ZSTD_CCtx* cctx,
void* dst, size_t dstCapacity, size_t* dstPos,
const void* src, size_t srcSize, size_t* srcPos,
ZSTD_EndDirective endOp);
/**
Block functions
@@ -784,7 +1087,7 @@ ZSTDLIB_API ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx* dctx);
+ compression : any ZSTD_compressBegin*() variant, including with dictionary
+ decompression : any ZSTD_decompressBegin*() variant, including with dictionary
+ copyCCtx() and copyDCtx() can be used too
- Block size is limited, it must be <= ZSTD_getBlockSizeMax() <= ZSTD_BLOCKSIZE_ABSOLUTEMAX
- Block size is limited, it must be <= ZSTD_getBlockSize() <= ZSTD_BLOCKSIZE_MAX
+ If input is larger than a block size, it's necessary to split input data into multiple blocks
+ For inputs larger than a single block size, consider using the regular ZSTD_compress() instead.
Frame metadata is not that costly, and quickly becomes negligible as source size grows larger.
@@ -797,9 +1100,10 @@ ZSTDLIB_API ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx* dctx);
Use ZSTD_insertBlock() for such a case.
*/
#define ZSTD_BLOCKSIZE_ABSOLUTEMAX (128 * 1024) /* define, for static allocation */
#define ZSTD_BLOCKSIZELOG_MAX 17
#define ZSTD_BLOCKSIZE_MAX (1<<ZSTD_BLOCKSIZELOG_MAX) /* define, for static allocation */
/*===== Raw zstd block functions =====*/
ZSTDLIB_API size_t ZSTD_getBlockSizeMax(ZSTD_CCtx* cctx);
ZSTDLIB_API size_t ZSTD_getBlockSize (const ZSTD_CCtx* cctx);
ZSTDLIB_API size_t ZSTD_compressBlock (ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
ZSTDLIB_API size_t ZSTD_decompressBlock(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
ZSTDLIB_API size_t ZSTD_insertBlock(ZSTD_DCtx* dctx, const void* blockStart, size_t blockSize); /**< insert block into `dctx` history. Useful for uncompressed blocks */