zstd.h
673 lines
| 37.2 KiB
| text/x-c
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CLexer
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r30434 | /* | ||
* Copyright (c) 2016-present, Yann Collet, Facebook, Inc. | ||||
* All rights reserved. | ||||
* | ||||
* This source code is licensed under the BSD-style license found in the | ||||
* LICENSE file in the root directory of this source tree. An additional grant | ||||
* of patent rights can be found in the PATENTS file in the same directory. | ||||
*/ | ||||
#if defined (__cplusplus) | ||||
extern "C" { | ||||
#endif | ||||
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r30822 | #ifndef ZSTD_H_235446 | ||
#define ZSTD_H_235446 | ||||
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r30434 | /* ====== Dependency ======*/ | ||
#include <stddef.h> /* size_t */ | ||||
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r30822 | /* ===== ZSTDLIB_API : control library symbols visibility ===== */ | ||
#if defined(__GNUC__) && (__GNUC__ >= 4) | ||||
# define ZSTDLIB_API __attribute__ ((visibility ("default"))) | ||||
#elif defined(ZSTD_DLL_EXPORT) && (ZSTD_DLL_EXPORT==1) | ||||
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r30434 | # define ZSTDLIB_API __declspec(dllexport) | ||
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r30822 | #elif defined(ZSTD_DLL_IMPORT) && (ZSTD_DLL_IMPORT==1) | ||
# define ZSTDLIB_API __declspec(dllimport) /* It isn't required but allows to generate better code, saving a function pointer load from the IAT and an indirect jump.*/ | ||||
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r30434 | #else | ||
# define ZSTDLIB_API | ||||
#endif | ||||
/******************************************************************************************************* | ||||
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. | ||||
Levels >= 20, labelled `--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: | ||||
- 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. | ||||
They are not "stable", their definition may change in the future. Only static linking is allowed. | ||||
*********************************************************************************************************/ | ||||
/*------ Version ------*/ | ||||
#define ZSTD_VERSION_MAJOR 1 | ||||
#define ZSTD_VERSION_MINOR 1 | ||||
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r30822 | #define ZSTD_VERSION_RELEASE 2 | ||
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r30434 | |||
#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) | ||||
#define ZSTD_VERSION_NUMBER (ZSTD_VERSION_MAJOR *100*100 + ZSTD_VERSION_MINOR *100 + ZSTD_VERSION_RELEASE) | ||||
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r30822 | ZSTDLIB_API unsigned ZSTD_versionNumber(void); /**< library version number; to be used when checking dll version */ | ||
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r30434 | |||
/*************************************** | ||||
* Simple API | ||||
***************************************/ | ||||
/*! ZSTD_compress() : | ||||
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), | ||||
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r30822 | or an error code if it fails (which can be tested using ZSTD_isError()). */ | ||
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r30434 | ZSTDLIB_API size_t ZSTD_compress( void* dst, size_t dstCapacity, | ||
const void* src, size_t srcSize, | ||||
int compressionLevel); | ||||
/*! ZSTD_decompress() : | ||||
`compressedSize` : must be the _exact_ size of a single compressed frame. | ||||
`dstCapacity` is an upper bound of originalSize. | ||||
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`), | ||||
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r30822 | or an errorCode if it fails (which can be tested using ZSTD_isError()). */ | ||
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r30434 | ZSTDLIB_API size_t ZSTD_decompress( void* dst, size_t dstCapacity, | ||
const void* src, size_t compressedSize); | ||||
/*! ZSTD_getDecompressedSize() : | ||||
* '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. | ||||
* 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. | ||||
* (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), | ||||
* potentially larger than what local system can handle as a single memory segment. | ||||
* In which case, it's necessary to use streaming mode to decompress data. | ||||
* 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. */ | ||||
ZSTDLIB_API unsigned long long ZSTD_getDecompressedSize(const void* src, size_t srcSize); | ||||
/*====== Helper functions ======*/ | ||||
ZSTDLIB_API int ZSTD_maxCLevel(void); /*!< maximum compression level available */ | ||||
ZSTDLIB_API size_t ZSTD_compressBound(size_t srcSize); /*!< maximum compressed size in worst case scenario */ | ||||
ZSTDLIB_API unsigned ZSTD_isError(size_t code); /*!< tells if a `size_t` function result is an error code */ | ||||
ZSTDLIB_API const char* ZSTD_getErrorName(size_t code); /*!< provides readable string from an error code */ | ||||
/*************************************** | ||||
* Explicit memory management | ||||
***************************************/ | ||||
/*= Compression context | ||||
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r30822 | * When compressing many times, | ||
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r30434 | * it is recommended to allocate a context just once, and re-use it for each successive compression operation. | ||
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r30822 | * This will make workload friendlier for system's memory. | ||
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r30434 | * Use one context per thread for parallel execution in multi-threaded environments. */ | ||
typedef struct ZSTD_CCtx_s ZSTD_CCtx; | ||||
ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx(void); | ||||
ZSTDLIB_API size_t ZSTD_freeCCtx(ZSTD_CCtx* cctx); | ||||
/*! ZSTD_compressCCtx() : | ||||
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r30822 | Same as ZSTD_compress(), requires an allocated ZSTD_CCtx (see ZSTD_createCCtx()). */ | ||
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r30434 | ZSTDLIB_API size_t ZSTD_compressCCtx(ZSTD_CCtx* ctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize, int compressionLevel); | ||
/*= Decompression context */ | ||||
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() : | ||||
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r30822 | * Same as ZSTD_decompress(), requires an allocated ZSTD_DCtx (see ZSTD_createDCtx()). */ | ||
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r30434 | 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). | ||||
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r30822 | * Note : This function loads the dictionary, resulting in significant startup delay. | ||
* Note : When `dict == NULL || dictSize < 8` no dictionary is used. */ | ||||
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r30434 | ZSTDLIB_API size_t ZSTD_compress_usingDict(ZSTD_CCtx* ctx, | ||
void* dst, size_t dstCapacity, | ||||
const void* src, size_t srcSize, | ||||
const void* dict,size_t dictSize, | ||||
int compressionLevel); | ||||
/*! ZSTD_decompress_usingDict() : | ||||
* Decompression using a predefined Dictionary (see dictBuilder/zdict.h). | ||||
* Dictionary must be identical to the one used during compression. | ||||
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r30822 | * Note : This function loads the dictionary, resulting in significant startup delay. | ||
* Note : When `dict == NULL || dictSize < 8` no dictionary is used. */ | ||||
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r30434 | 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 | ||||
****************************/ | ||||
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. | ||||
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r30822 | * `dict` can be released after ZSTD_CDict creation. */ | ||
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r30434 | ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict(const void* dict, size_t dictSize, int compressionLevel); | ||
/*! ZSTD_freeCDict() : | ||||
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r30822 | * Function frees memory allocated by ZSTD_createCDict(). */ | ||
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r30434 | ZSTDLIB_API size_t ZSTD_freeCDict(ZSTD_CDict* CDict); | ||
/*! ZSTD_compress_usingCDict() : | ||||
* Compression using a digested Dictionary. | ||||
* Faster startup than ZSTD_compress_usingDict(), recommended when same dictionary is used multiple times. | ||||
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r30822 | * Note that compression level is decided during dictionary creation. */ | ||
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r30434 | ZSTDLIB_API size_t ZSTD_compress_usingCDict(ZSTD_CCtx* cctx, | ||
void* dst, size_t dstCapacity, | ||||
const void* src, size_t srcSize, | ||||
const ZSTD_CDict* cdict); | ||||
typedef struct ZSTD_DDict_s ZSTD_DDict; | ||||
/*! ZSTD_createDDict() : | ||||
* Create a digested dictionary, ready to start decompression operation without startup delay. | ||||
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r30822 | * `dict` can be released after creation. */ | ||
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r30434 | ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict(const void* dict, size_t dictSize); | ||
/*! ZSTD_freeDDict() : | ||||
* Function frees memory allocated with ZSTD_createDDict() */ | ||||
ZSTDLIB_API size_t ZSTD_freeDDict(ZSTD_DDict* ddict); | ||||
/*! ZSTD_decompress_usingDDict() : | ||||
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r30822 | * Decompression using a digested Dictionary. | ||
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r30434 | * 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, | ||||
const ZSTD_DDict* ddict); | ||||
/**************************** | ||||
* Streaming | ||||
****************************/ | ||||
typedef struct ZSTD_inBuffer_s { | ||||
const void* src; /**< start of input buffer */ | ||||
size_t size; /**< size of input buffer */ | ||||
size_t pos; /**< position where reading stopped. Will be updated. Necessarily 0 <= pos <= size */ | ||||
} ZSTD_inBuffer; | ||||
typedef struct ZSTD_outBuffer_s { | ||||
void* dst; /**< start of output buffer */ | ||||
size_t size; /**< size of output buffer */ | ||||
size_t pos; /**< position where writing stopped. Will be updated. Necessarily 0 <= pos <= size */ | ||||
} ZSTD_outBuffer; | ||||
/*-*********************************************************************** | ||||
* Streaming compression - HowTo | ||||
* | ||||
* A ZSTD_CStream object is required to track streaming operation. | ||||
* Use ZSTD_createCStream() and ZSTD_freeCStream() to create/release resources. | ||||
* ZSTD_CStream objects can be reused multiple times on consecutive compression operations. | ||||
* It is recommended to re-use ZSTD_CStream in situations where many streaming operations will be achieved consecutively, | ||||
* since it will play nicer with system's memory, by re-using already allocated memory. | ||||
* Use one separate ZSTD_CStream per thread for parallel execution. | ||||
* | ||||
* Start a new compression by initializing ZSTD_CStream. | ||||
* Use ZSTD_initCStream() to start a new compression operation. | ||||
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r30822 | * Use ZSTD_initCStream_usingDict() or ZSTD_initCStream_usingCDict() for a compression which requires a dictionary (experimental section) | ||
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r30434 | * | ||
* Use ZSTD_compressStream() repetitively to consume input stream. | ||||
* The function will automatically update both `pos` fields. | ||||
* Note that it may not consume the entire input, in which case `pos < size`, | ||||
* and it's up to the caller to present again remaining data. | ||||
* @return : a size hint, preferred nb of bytes to use as input for next function call | ||||
* or an error code, which can be tested using ZSTD_isError(). | ||||
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r30822 | * Note 1 : it's just a hint, to help latency a little, any other value will work fine. | ||
* Note 2 : size hint is guaranteed to be <= ZSTD_CStreamInSize() | ||||
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r30434 | * | ||
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r30822 | * At any moment, it's possible to flush whatever data remains within internal buffer, using ZSTD_flushStream(). | ||
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r30434 | * `output->pos` will be updated. | ||
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r30822 | * Note that some content might still be left within internal buffer if `output->size` is too small. | ||
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r30434 | * @return : nb of bytes still present within internal buffer (0 if it's empty) | ||
* or an error code, which can be tested using ZSTD_isError(). | ||||
* | ||||
* 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. | ||||
* In which case, call again ZSTD_endStream() to complete the flush. | ||||
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r30822 | * @return : nb of bytes still present within internal buffer (0 if it's empty, hence compression completed) | ||
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r30434 | * or an error code, which can be tested using ZSTD_isError(). | ||
* | ||||
* *******************************************************************/ | ||||
typedef struct ZSTD_CStream_s ZSTD_CStream; | ||||
ZSTDLIB_API ZSTD_CStream* ZSTD_createCStream(void); | ||||
ZSTDLIB_API size_t ZSTD_freeCStream(ZSTD_CStream* zcs); | ||||
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r30822 | |||
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r30434 | ZSTDLIB_API size_t ZSTD_initCStream(ZSTD_CStream* zcs, int compressionLevel); | ||
ZSTDLIB_API size_t ZSTD_compressStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output, ZSTD_inBuffer* input); | ||||
ZSTDLIB_API size_t ZSTD_flushStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output); | ||||
ZSTDLIB_API size_t ZSTD_endStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output); | ||||
ZSTDLIB_API size_t ZSTD_CStreamInSize(void); /**< recommended size for input buffer */ | ||||
ZSTDLIB_API size_t ZSTD_CStreamOutSize(void); /**< recommended size for output buffer. Guarantee to successfully flush at least one complete compressed block in all circumstances. */ | ||||
/*-*************************************************************************** | ||||
* Streaming decompression - HowTo | ||||
* | ||||
* A ZSTD_DStream object is required to track streaming operations. | ||||
* Use ZSTD_createDStream() and ZSTD_freeDStream() to create/release resources. | ||||
* ZSTD_DStream objects can be re-used multiple times. | ||||
* | ||||
* Use ZSTD_initDStream() to start a new decompression operation, | ||||
* or ZSTD_initDStream_usingDict() if decompression requires a dictionary. | ||||
* @return : recommended first input size | ||||
* | ||||
* Use ZSTD_decompressStream() repetitively to consume your input. | ||||
* The function will update both `pos` fields. | ||||
* If `input.pos < input.size`, some input has not been consumed. | ||||
* It's up to the caller to present again remaining data. | ||||
* If `output.pos < output.size`, decoder has flushed everything it could. | ||||
* @return : 0 when a frame is completely decoded and fully flushed, | ||||
* an error code, which can be tested using ZSTD_isError(), | ||||
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r30822 | * any other value > 0, which means there is still some decoding to do to complete current frame. | ||
* The return value is a suggested next input size (a hint to improve latency) that will never load more than the current frame. | ||||
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r30434 | * *******************************************************************************/ | ||
typedef struct ZSTD_DStream_s ZSTD_DStream; | ||||
ZSTDLIB_API ZSTD_DStream* ZSTD_createDStream(void); | ||||
ZSTDLIB_API size_t ZSTD_freeDStream(ZSTD_DStream* zds); | ||||
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r30822 | |||
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r30434 | ZSTDLIB_API size_t ZSTD_initDStream(ZSTD_DStream* zds); | ||
ZSTDLIB_API size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inBuffer* input); | ||||
ZSTDLIB_API size_t ZSTD_DStreamInSize(void); /*!< recommended size for input buffer */ | ||||
ZSTDLIB_API size_t ZSTD_DStreamOutSize(void); /*!< recommended size for output buffer. Guarantee to successfully flush at least one complete block in all circumstances. */ | ||||
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r30822 | #endif /* ZSTD_H_235446 */ | ||
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r30434 | |||
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r30822 | #if defined(ZSTD_STATIC_LINKING_ONLY) && !defined(ZSTD_H_ZSTD_STATIC_LINKING_ONLY) | ||
#define ZSTD_H_ZSTD_STATIC_LINKING_ONLY | ||||
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r30434 | |||
/**************************************************************************************** | ||||
* START OF ADVANCED AND EXPERIMENTAL FUNCTIONS | ||||
* The definitions in this section are considered experimental. | ||||
* They should never be used with a dynamic library, as they may change in the future. | ||||
* They are provided for advanced usages. | ||||
* Use them only in association with static linking. | ||||
* ***************************************************************************************/ | ||||
/* --- Constants ---*/ | ||||
#define ZSTD_MAGICNUMBER 0xFD2FB528 /* v0.8 */ | ||||
#define ZSTD_MAGIC_SKIPPABLE_START 0x184D2A50U | ||||
#define ZSTD_WINDOWLOG_MAX_32 25 | ||||
#define ZSTD_WINDOWLOG_MAX_64 27 | ||||
#define ZSTD_WINDOWLOG_MAX ((U32)(MEM_32bits() ? ZSTD_WINDOWLOG_MAX_32 : ZSTD_WINDOWLOG_MAX_64)) | ||||
#define ZSTD_WINDOWLOG_MIN 10 | ||||
#define ZSTD_HASHLOG_MAX ZSTD_WINDOWLOG_MAX | ||||
#define ZSTD_HASHLOG_MIN 6 | ||||
#define ZSTD_CHAINLOG_MAX (ZSTD_WINDOWLOG_MAX+1) | ||||
#define ZSTD_CHAINLOG_MIN ZSTD_HASHLOG_MIN | ||||
#define ZSTD_HASHLOG3_MAX 17 | ||||
#define ZSTD_SEARCHLOG_MAX (ZSTD_WINDOWLOG_MAX-1) | ||||
#define ZSTD_SEARCHLOG_MIN 1 | ||||
#define ZSTD_SEARCHLENGTH_MAX 7 /* only for ZSTD_fast, other strategies are limited to 6 */ | ||||
#define ZSTD_SEARCHLENGTH_MIN 3 /* only for ZSTD_btopt, other strategies are limited to 4 */ | ||||
#define ZSTD_TARGETLENGTH_MIN 4 | ||||
#define ZSTD_TARGETLENGTH_MAX 999 | ||||
#define ZSTD_FRAMEHEADERSIZE_MAX 18 /* for static allocation */ | ||||
static const size_t ZSTD_frameHeaderSize_prefix = 5; | ||||
static const size_t ZSTD_frameHeaderSize_min = 6; | ||||
static const size_t ZSTD_frameHeaderSize_max = ZSTD_FRAMEHEADERSIZE_MAX; | ||||
static const size_t ZSTD_skippableHeaderSize = 8; /* magic number + skippable frame length */ | ||||
/*--- Advanced types ---*/ | ||||
typedef enum { ZSTD_fast, ZSTD_dfast, ZSTD_greedy, ZSTD_lazy, ZSTD_lazy2, ZSTD_btlazy2, ZSTD_btopt, ZSTD_btopt2 } ZSTD_strategy; /* from faster to stronger */ | ||||
typedef struct { | ||||
unsigned windowLog; /**< largest match distance : larger == more compression, more memory needed during decompression */ | ||||
unsigned chainLog; /**< fully searched segment : larger == more compression, slower, more memory (useless for fast) */ | ||||
unsigned hashLog; /**< dispatch table : larger == faster, more memory */ | ||||
unsigned searchLog; /**< nb of searches : larger == more compression, slower */ | ||||
unsigned searchLength; /**< match length searched : larger == faster decompression, sometimes less compression */ | ||||
unsigned targetLength; /**< acceptable match size for optimal parser (only) : larger == more compression, slower */ | ||||
ZSTD_strategy strategy; | ||||
} ZSTD_compressionParameters; | ||||
typedef struct { | ||||
unsigned contentSizeFlag; /**< 1: content size will be in frame header (if known). */ | ||||
unsigned checksumFlag; /**< 1: will generate a 22-bits checksum at end of frame, to be used for error detection by decompressor */ | ||||
unsigned noDictIDFlag; /**< 1: no dict ID will be saved into frame header (if dictionary compression) */ | ||||
} ZSTD_frameParameters; | ||||
typedef struct { | ||||
ZSTD_compressionParameters cParams; | ||||
ZSTD_frameParameters fParams; | ||||
} ZSTD_parameters; | ||||
/*= Custom memory allocation functions */ | ||||
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; | ||||
/*************************************** | ||||
* Advanced compression functions | ||||
***************************************/ | ||||
/*! ZSTD_estimateCCtxSize() : | ||||
* Gives the amount of memory allocated for a ZSTD_CCtx given a set of compression parameters. | ||||
* `frameContentSize` is an optional parameter, provide `0` if unknown */ | ||||
ZSTDLIB_API size_t ZSTD_estimateCCtxSize(ZSTD_compressionParameters cParams); | ||||
/*! ZSTD_createCCtx_advanced() : | ||||
* Create a ZSTD compression context using external alloc and free functions */ | ||||
ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem); | ||||
/*! ZSTD_sizeofCCtx() : | ||||
* Gives the amount of memory used by a given ZSTD_CCtx */ | ||||
ZSTDLIB_API size_t ZSTD_sizeof_CCtx(const ZSTD_CCtx* cctx); | ||||
/*! 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, | ||||
ZSTD_parameters params, ZSTD_customMem customMem); | ||||
/*! ZSTD_sizeof_CDict() : | ||||
* Gives the amount of memory used by a given ZSTD_sizeof_CDict */ | ||||
ZSTDLIB_API size_t ZSTD_sizeof_CDict(const ZSTD_CDict* cdict); | ||||
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r30822 | /*! ZSTD_getCParams() : | ||
* @return ZSTD_compressionParameters structure for a selected compression level and estimated srcSize. | ||||
* `estimatedSrcSize` value is optional, select 0 if not known */ | ||||
ZSTDLIB_API ZSTD_compressionParameters ZSTD_getCParams(int compressionLevel, unsigned long long estimatedSrcSize, size_t dictSize); | ||||
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r30434 | |||
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r30822 | /*! 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 (0) */ | ||||
ZSTDLIB_API ZSTD_parameters ZSTD_getParams(int compressionLevel, unsigned long long estimatedSrcSize, size_t dictSize); | ||||
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r30434 | |||
/*! ZSTD_checkCParams() : | ||||
* Ensure param values remain within authorized range */ | ||||
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. */ | ||||
ZSTDLIB_API ZSTD_compressionParameters ZSTD_adjustCParams(ZSTD_compressionParameters cPar, unsigned long long srcSize, size_t dictSize); | ||||
/*! ZSTD_compress_advanced() : | ||||
* Same as ZSTD_compress_usingDict(), with fine-tune control of each compression parameter */ | ||||
ZSTDLIB_API size_t ZSTD_compress_advanced (ZSTD_CCtx* ctx, | ||||
void* dst, size_t dstCapacity, | ||||
const void* src, size_t srcSize, | ||||
const void* dict,size_t dictSize, | ||||
ZSTD_parameters params); | ||||
/*--- Advanced decompression functions ---*/ | ||||
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r30822 | /*! 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. */ | ||||
ZSTDLIB_API unsigned ZSTD_isFrame(const void* buffer, size_t size); | ||||
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r30434 | /*! ZSTD_estimateDCtxSize() : | ||
* Gives the potential amount of memory allocated to create a ZSTD_DCtx */ | ||||
ZSTDLIB_API size_t ZSTD_estimateDCtxSize(void); | ||||
/*! ZSTD_createDCtx_advanced() : | ||||
* Create a ZSTD decompression context using external alloc and free functions */ | ||||
ZSTDLIB_API ZSTD_DCtx* ZSTD_createDCtx_advanced(ZSTD_customMem customMem); | ||||
/*! ZSTD_sizeof_DCtx() : | ||||
* Gives the amount of memory used by a given ZSTD_DCtx */ | ||||
ZSTDLIB_API size_t ZSTD_sizeof_DCtx(const ZSTD_DCtx* dctx); | ||||
/*! ZSTD_sizeof_DDict() : | ||||
* Gives the amount of memory used by a given ZSTD_DDict */ | ||||
ZSTDLIB_API size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict); | ||||
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r30822 | /*! 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. */ | ||||
unsigned ZSTD_getDictID_fromDict(const void* dict, size_t dictSize); | ||||
/*! 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. */ | ||||
unsigned ZSTD_getDictID_fromDDict(const ZSTD_DDict* ddict); | ||||
/*! 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 : | ||||
* - The frame does not require a dictionary to be decoded (most common case). | ||||
* - The frame was built with dictID intentionally removed. Whatever dictionary is necessary is a hidden information. | ||||
* 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 used ZSTD_getFrameParams(), which will provide a more precise error code. */ | ||||
unsigned ZSTD_getDictID_fromFrame(const void* src, size_t srcSize); | ||||
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r30434 | |||
/******************************************************************** | ||||
* Advanced streaming functions | ||||
********************************************************************/ | ||||
/*===== Advanced Streaming compression functions =====*/ | ||||
ZSTDLIB_API ZSTD_CStream* ZSTD_createCStream_advanced(ZSTD_customMem customMem); | ||||
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r30822 | ZSTDLIB_API size_t ZSTD_initCStream_srcSize(ZSTD_CStream* zcs, int compressionLevel, unsigned long long pledgedSrcSize); /**< pledgedSrcSize must be correct */ | ||
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r30434 | ZSTDLIB_API size_t ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, const void* dict, size_t dictSize, int compressionLevel); | ||
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 zero == unknown */ | ||||
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_resetCStream(ZSTD_CStream* zcs, unsigned long long pledgedSrcSize); /**< re-use compression parameters from previous init; skip dictionary loading stage; zcs must be init at least once before */ | ||||
ZSTDLIB_API size_t ZSTD_sizeof_CStream(const ZSTD_CStream* zcs); | ||||
/*===== Advanced Streaming decompression functions =====*/ | ||||
typedef enum { ZSTDdsp_maxWindowSize } ZSTD_DStreamParameter_e; | ||||
ZSTDLIB_API ZSTD_DStream* ZSTD_createDStream_advanced(ZSTD_customMem customMem); | ||||
ZSTDLIB_API size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize); | ||||
ZSTDLIB_API size_t ZSTD_setDStreamParameter(ZSTD_DStream* zds, ZSTD_DStreamParameter_e paramType, unsigned paramValue); | ||||
ZSTDLIB_API size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* zds, const ZSTD_DDict* ddict); /**< note : ddict will just be referenced, and must outlive decompression session */ | ||||
ZSTDLIB_API size_t ZSTD_resetDStream(ZSTD_DStream* zds); /**< re-use decompression parameters from previous init; saves dictionary loading */ | ||||
ZSTDLIB_API size_t ZSTD_sizeof_DStream(const ZSTD_DStream* zds); | ||||
/********************************************************************* | ||||
* Buffer-less and synchronous inner streaming functions | ||||
* | ||||
* This is an advanced API, giving full control over buffer management, for users which need direct control over memory. | ||||
* But it's also a complex one, with many restrictions (documented below). | ||||
* Prefer using normal streaming API for an easier experience | ||||
********************************************************************* */ | ||||
/** | ||||
Buffer-less streaming compression (synchronous mode) | ||||
A ZSTD_CCtx object is required to track streaming operations. | ||||
Use ZSTD_createCCtx() / ZSTD_freeCCtx() to manage resource. | ||||
ZSTD_CCtx object can be re-used multiple times within successive compression operations. | ||||
Start by initializing a context. | ||||
Use ZSTD_compressBegin(), or ZSTD_compressBegin_usingDict() for dictionary compression, | ||||
or ZSTD_compressBegin_advanced(), for finer parameter control. | ||||
It's also possible to duplicate a reference context which has already been initialized, using ZSTD_copyCCtx() | ||||
Then, consume your input using ZSTD_compressContinue(). | ||||
There are some important considerations to keep in mind when using this advanced function : | ||||
- ZSTD_compressContinue() has no internal buffer. It uses externally provided buffer only. | ||||
- Interface is synchronous : input is consumed entirely and produce 1+ (or more) compressed blocks. | ||||
- Caller must ensure there is enough space in `dst` to store compressed data under worst case scenario. | ||||
Worst case evaluation is provided by ZSTD_compressBound(). | ||||
ZSTD_compressContinue() doesn't guarantee recover after a failed compression. | ||||
- ZSTD_compressContinue() presumes prior input ***is still accessible and unmodified*** (up to maximum distance size, see WindowLog). | ||||
It remembers all previous contiguous blocks, plus one separated memory segment (which can itself consists of multiple contiguous blocks) | ||||
- ZSTD_compressContinue() detects that prior input has been overwritten when `src` buffer overlaps. | ||||
In which case, it will "discard" the relevant memory section from its history. | ||||
Finish a frame with ZSTD_compressEnd(), which will write the last block(s) and optional checksum. | ||||
It's possible to use a NULL,0 src content, in which case, it will write a final empty block to end the frame, | ||||
Without last block mark, frames will be considered unfinished (broken) by decoders. | ||||
You can then reuse `ZSTD_CCtx` (ZSTD_compressBegin()) to compress some new frame. | ||||
*/ | ||||
/*===== Buffer-less streaming compression functions =====*/ | ||||
ZSTDLIB_API size_t ZSTD_compressBegin(ZSTD_CCtx* cctx, int compressionLevel); | ||||
ZSTDLIB_API size_t ZSTD_compressBegin_usingDict(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, int compressionLevel); | ||||
ZSTDLIB_API size_t ZSTD_compressBegin_advanced(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, ZSTD_parameters params, unsigned long long pledgedSrcSize); | ||||
ZSTDLIB_API size_t ZSTD_copyCCtx(ZSTD_CCtx* cctx, const ZSTD_CCtx* preparedCCtx, unsigned long long pledgedSrcSize); | ||||
ZSTDLIB_API size_t ZSTD_compressContinue(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); | ||||
ZSTDLIB_API size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); | ||||
/*- | ||||
Buffer-less streaming decompression (synchronous mode) | ||||
A ZSTD_DCtx object is required to track streaming operations. | ||||
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(). | ||||
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. | ||||
(Note : content size is optional, it may not be present. 0 means : content size unknown). | ||||
Note that these values could be wrong, either because of data malformation, or because an attacker is spoofing deliberate false information. | ||||
As a consequence, check that values remain within valid application range, especially `windowSize`, before allocation. | ||||
Each application can set its own limit, depending on local restrictions. For extended interoperability, it is recommended to support at least 8 MB. | ||||
Frame parameters are extracted from the beginning of the compressed frame. | ||||
Data fragment must be large enough to ensure successful decoding, typically `ZSTD_frameHeaderSize_max` bytes. | ||||
@result : 0 : successful decoding, the `ZSTD_frameParams` structure is correctly filled. | ||||
>0 : `srcSize` is too small, please provide at least @result bytes on next attempt. | ||||
errorCode, which can be tested using ZSTD_isError(). | ||||
Start decompression, with ZSTD_decompressBegin() or ZSTD_decompressBegin_usingDict(). | ||||
Alternatively, you can copy a prepared context, using ZSTD_copyDCtx(). | ||||
Then use ZSTD_nextSrcSizeToDecompress() and ZSTD_decompressContinue() alternatively. | ||||
ZSTD_nextSrcSizeToDecompress() tells how many bytes to provide as 'srcSize' to ZSTD_decompressContinue(). | ||||
ZSTD_decompressContinue() requires this _exact_ amount of bytes, or it will fail. | ||||
@result of ZSTD_decompressContinue() is the number of bytes regenerated within 'dst' (necessarily <= dstCapacity). | ||||
It can be zero, which is not an error; it just means ZSTD_decompressContinue() has decoded some metadata item. | ||||
It can also be an error code, which can be tested with ZSTD_isError(). | ||||
ZSTD_decompressContinue() needs previous data blocks during decompression, up to `windowSize`. | ||||
They should preferably be located contiguously, prior to current block. | ||||
Alternatively, a round buffer of sufficient size is also possible. Sufficient size is determined by frame parameters. | ||||
ZSTD_decompressContinue() is very sensitive to contiguity, | ||||
if 2 blocks don't follow each other, make sure that either the compressor breaks contiguity at the same place, | ||||
or that previous contiguous segment is large enough to properly handle maximum back-reference. | ||||
A frame is fully decoded when ZSTD_nextSrcSizeToDecompress() returns zero. | ||||
Context can then be reset to start a new decompression. | ||||
Note : it's possible to know if next input to present is a header or a block, using ZSTD_nextInputType(). | ||||
This information is not required to properly decode a frame. | ||||
== Special case : skippable frames == | ||||
Skippable frames allow integration of user-defined data into a flow of concatenated frames. | ||||
Skippable frames will be ignored (skipped) by a decompressor. The format of skippable frames is as follows : | ||||
a) Skippable frame ID - 4 Bytes, Little endian format, any value from 0x184D2A50 to 0x184D2A5F | ||||
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. | ||||
It also returns Frame Size as fparamsPtr->frameContentSize. | ||||
*/ | ||||
typedef struct { | ||||
unsigned long long frameContentSize; | ||||
unsigned windowSize; | ||||
unsigned dictID; | ||||
unsigned checksumFlag; | ||||
} ZSTD_frameParams; | ||||
/*===== Buffer-less streaming decompression functions =====*/ | ||||
ZSTDLIB_API size_t ZSTD_getFrameParams(ZSTD_frameParams* fparamsPtr, const void* src, size_t srcSize); /**< doesn't consume input, see details below */ | ||||
ZSTDLIB_API size_t ZSTD_decompressBegin(ZSTD_DCtx* dctx); | ||||
ZSTDLIB_API size_t ZSTD_decompressBegin_usingDict(ZSTD_DCtx* dctx, const void* dict, size_t dictSize); | ||||
ZSTDLIB_API void ZSTD_copyDCtx(ZSTD_DCtx* dctx, const ZSTD_DCtx* preparedDCtx); | ||||
ZSTDLIB_API size_t ZSTD_nextSrcSizeToDecompress(ZSTD_DCtx* dctx); | ||||
ZSTDLIB_API size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); | ||||
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); | ||||
/** | ||||
Block functions | ||||
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. | ||||
A few rules to respect : | ||||
- Compressing and decompressing require a context structure | ||||
+ Use ZSTD_createCCtx() and ZSTD_createDCtx() | ||||
- It is necessary to init context before starting | ||||
+ compression : ZSTD_compressBegin() | ||||
+ decompression : ZSTD_decompressBegin() | ||||
+ variants _usingDict() are also allowed | ||||
+ copyCCtx() and copyDCtx() work too | ||||
- Block size is limited, it must be <= ZSTD_getBlockSizeMax() | ||||
+ If you need to compress more, cut data into multiple blocks | ||||
+ Consider using the regular ZSTD_compress() instead, as frame metadata costs become negligible when source size is large. | ||||
- When a block is considered not compressible enough, ZSTD_compressBlock() result will be zero. | ||||
In which case, nothing is produced into `dst`. | ||||
+ User must test for such outcome and deal directly with uncompressed data | ||||
+ ZSTD_decompressBlock() doesn't accept uncompressed data as input !!! | ||||
+ In case of multiple successive blocks, decoder must be informed of uncompressed block existence to follow proper history. | ||||
Use ZSTD_insertBlock() in such a case. | ||||
*/ | ||||
#define ZSTD_BLOCKSIZE_ABSOLUTEMAX (128 * 1024) /* define, for static allocation */ | ||||
/*===== Raw zstd block functions =====*/ | ||||
ZSTDLIB_API size_t ZSTD_getBlockSizeMax(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 */ | ||||
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r30822 | #endif /* ZSTD_H_ZSTD_STATIC_LINKING_ONLY */ | ||
|
r30434 | |||
#if defined (__cplusplus) | ||||
} | ||||
#endif | ||||