zstd.h
1516 lines
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| text/x-c
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CLexer
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r30434 | /* | ||
* Copyright (c) 2016-present, Yann Collet, Facebook, Inc. | ||||
* All rights reserved. | ||||
* | ||||
|
r37513 | * This source code is licensed under both the BSD-style license (found in the | ||
* LICENSE file in the root directory of this source tree) and the GPLv2 (found | ||||
* in the COPYING file in the root directory of this source tree). | ||||
* You may select, at your option, one of the above-listed licenses. | ||||
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r30434 | */ | ||
#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 ===== */ | ||
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r37513 | #ifndef ZSTDLIB_VISIBILITY | ||
# if defined(__GNUC__) && (__GNUC__ >= 4) | ||||
# define ZSTDLIB_VISIBILITY __attribute__ ((visibility ("default"))) | ||||
# else | ||||
# define ZSTDLIB_VISIBILITY | ||||
# endif | ||||
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r30895 | #endif | ||
#if defined(ZSTD_DLL_EXPORT) && (ZSTD_DLL_EXPORT==1) | ||||
# define ZSTDLIB_API __declspec(dllexport) ZSTDLIB_VISIBILITY | ||||
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r30822 | #elif defined(ZSTD_DLL_IMPORT) && (ZSTD_DLL_IMPORT==1) | ||
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r30895 | # define ZSTDLIB_API __declspec(dllimport) ZSTDLIB_VISIBILITY /* 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 | ||
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r30895 | # define ZSTDLIB_API ZSTDLIB_VISIBILITY | ||
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r30434 | #endif | ||
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r40157 | /******************************************************************************* | ||
|
r30434 | Introduction | ||
|
r40157 | 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 regular 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. The library also offers negative | ||||
compression levels, which extend the range of speed vs. ratio preferences. | ||||
The lower the level, the faster the speed (at the cost of compression). | ||||
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r30434 | Compression can be done in: | ||
- a single step (described as Simple API) | ||||
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r37513 | - a single step, reusing a context (described as Explicit context) | ||
|
r30434 | - unbounded multiple steps (described as Streaming compression) | ||
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r40157 | |||
The compression ratio achievable on small data can be highly improved using | ||||
a dictionary. Dictionary compression can be performed in: | ||||
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r30434 | - a single step (described as Simple dictionary API) | ||
|
r40157 | - a single step, reusing a dictionary (described as Bulk-processing | ||
dictionary API) | ||||
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r30434 | |||
|
r40157 | Advanced experimental functions can be accessed using | ||
`#define ZSTD_STATIC_LINKING_ONLY` before including zstd.h. | ||||
Advanced experimental APIs should never be used with a dynamically-linked | ||||
library. They are not "stable"; their definitions or signatures may change in | ||||
the future. Only static linking is allowed. | ||||
*******************************************************************************/ | ||||
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r30434 | |||
/*------ Version ------*/ | ||||
#define ZSTD_VERSION_MAJOR 1 | ||||
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r37513 | #define ZSTD_VERSION_MINOR 3 | ||
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r40157 | #define ZSTD_VERSION_RELEASE 6 | ||
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r37513 | |||
#define ZSTD_VERSION_NUMBER (ZSTD_VERSION_MAJOR *100*100 + ZSTD_VERSION_MINOR *100 + ZSTD_VERSION_RELEASE) | ||||
ZSTDLIB_API unsigned ZSTD_versionNumber(void); /**< useful to check dll version */ | ||||
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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) | ||||
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r40157 | ZSTDLIB_API const char* ZSTD_versionString(void); /* v1.3.0+ */ | ||
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r30434 | |||
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r40157 | /*************************************** | ||
* Default constant | ||||
***************************************/ | ||||
#ifndef ZSTD_CLEVEL_DEFAULT | ||||
# define ZSTD_CLEVEL_DEFAULT 3 | ||||
#endif | ||||
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r30434 | |||
/*************************************** | ||||
* Simple API | ||||
***************************************/ | ||||
/*! ZSTD_compress() : | ||||
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r37513 | * 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()). */ | ||||
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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() : | ||||
|
r37513 | * `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()). */ | ||||
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r30434 | ZSTDLIB_API size_t ZSTD_decompress( void* dst, size_t dstCapacity, | ||
const void* src, size_t compressedSize); | ||||
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r37513 | /*! ZSTD_getFrameContentSize() : added in v1.3.0 | ||
* `src` should point to the start of a ZSTD encoded frame. | ||||
* `srcSize` must be at least as large as the frame header. | ||||
* hint : any size >= `ZSTD_frameHeaderSize_max` is large enough. | ||||
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r40157 | * @return : - decompressed size of `src` frame content, if known | ||
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r37513 | * - ZSTD_CONTENTSIZE_UNKNOWN if the size cannot be determined | ||
* - ZSTD_CONTENTSIZE_ERROR if an error occurred (e.g. invalid magic number, srcSize too small) | ||||
* note 1 : a 0 return value means the frame is valid but "empty". | ||||
* note 2 : decompressed size is an optional field, it may not be present, typically in streaming mode. | ||||
* When `return==ZSTD_CONTENTSIZE_UNKNOWN`, data to decompress could be any size. | ||||
* In which case, it's necessary to use streaming mode to decompress data. | ||||
* Optionally, application can rely on some implicit limit, | ||||
* as ZSTD_decompress() only needs an upper bound of decompressed size. | ||||
* (For example, data could be necessarily cut into blocks <= 16 KB). | ||||
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r40157 | * note 3 : decompressed size is always present when compression is completed using single-pass functions, | ||
* such as ZSTD_compress(), ZSTD_compressCCtx() ZSTD_compress_usingDict() or ZSTD_compress_usingCDict(). | ||||
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r37513 | * note 4 : 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 5 : If source is untrusted, decompressed size could be wrong or intentionally modified. | ||||
* Always ensure return value fits within application's authorized limits. | ||||
* Each application can set its own limits. | ||||
* note 6 : This function replaces ZSTD_getDecompressedSize() */ | ||||
#define ZSTD_CONTENTSIZE_UNKNOWN (0ULL - 1) | ||||
#define ZSTD_CONTENTSIZE_ERROR (0ULL - 2) | ||||
ZSTDLIB_API unsigned long long ZSTD_getFrameContentSize(const void *src, size_t srcSize); | ||||
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r30434 | /*! ZSTD_getDecompressedSize() : | ||
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r37513 | * 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. | ||||
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r40157 | * @return : decompressed size of `src` frame content _if known and not empty_, 0 otherwise. */ | ||
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r30434 | ZSTDLIB_API unsigned long long ZSTD_getDecompressedSize(const void* src, size_t srcSize); | ||
/*====== Helper functions ======*/ | ||||
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r37513 | #define ZSTD_COMPRESSBOUND(srcSize) ((srcSize) + ((srcSize)>>8) + (((srcSize) < (128<<10)) ? (((128<<10) - (srcSize)) >> 11) /* margin, from 64 to 0 */ : 0)) /* this formula ensures that bound(A) + bound(B) <= bound(A+B) as long as A and B >= 128 KB */ | ||
ZSTDLIB_API size_t ZSTD_compressBound(size_t srcSize); /*!< maximum compressed size in worst case single-pass scenario */ | ||||
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r30434 | 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 */ | ||||
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r37513 | ZSTDLIB_API int ZSTD_maxCLevel(void); /*!< maximum compression level available */ | ||
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r30434 | |||
/*************************************** | ||||
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r37513 | * Explicit context | ||
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r30434 | ***************************************/ | ||
/*= Compression context | ||||
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r37513 | * When compressing many times, | ||
* it is recommended to allocate a context just 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. */ | ||||
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r30434 | 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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r37513 | * 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); | ||||
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r30434 | |||
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r37513 | /*= Decompression context | ||
* When decompressing many times, | ||||
* 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. */ | ||||
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r30434 | 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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r37513 | * 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); | ||||
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r30434 | |||
/************************** | ||||
* Simple dictionary API | ||||
***************************/ | ||||
/*! ZSTD_compress_usingDict() : | ||||
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r37513 | * 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. */ | ||||
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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() : | ||||
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r37513 | * 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. */ | ||||
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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); | ||||
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r37513 | /********************************** | ||
* Bulk processing dictionary API | ||||
*********************************/ | ||||
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r30434 | typedef struct ZSTD_CDict_s ZSTD_CDict; | ||
/*! ZSTD_createCDict() : | ||||
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r37513 | * 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. | ||||
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r40157 | * `dictBuffer` can be released after ZSTD_CDict creation, since its content is copied within CDict | ||
* Note : A ZSTD_CDict can be created with an empty dictionary, but it is inefficient for small data. */ | ||||
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r37513 | ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict(const void* dictBuffer, size_t dictSize, | ||
int compressionLevel); | ||||
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r30434 | |||
/*! ZSTD_freeCDict() : | ||||
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r37513 | * Function frees memory allocated by ZSTD_createCDict(). */ | ||
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r30434 | ZSTDLIB_API size_t ZSTD_freeCDict(ZSTD_CDict* CDict); | ||
/*! ZSTD_compress_usingCDict() : | ||||
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r37513 | * Compression using a digested Dictionary. | ||
* Faster startup than ZSTD_compress_usingDict(), recommended when same dictionary is used multiple times. | ||||
* Note that compression level is decided during dictionary creation. | ||||
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r40157 | * Frame parameters are hardcoded (dictID=yes, contentSize=yes, checksum=no) | ||
* Note : ZSTD_compress_usingCDict() can be used with a ZSTD_CDict created from an empty dictionary. | ||||
* But it is inefficient for small data, and it is recommended to use ZSTD_compressCCtx(). */ | ||||
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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() : | ||||
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r37513 | * 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 */ | ||||
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r30895 | ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict(const void* dictBuffer, size_t dictSize); | ||
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r30434 | |||
/*! ZSTD_freeDDict() : | ||||
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r37513 | * Function frees memory allocated with ZSTD_createDDict() */ | ||
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r30434 | ZSTDLIB_API size_t ZSTD_freeDDict(ZSTD_DDict* ddict); | ||
/*! ZSTD_decompress_usingDDict() : | ||||
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r37513 | * Decompression using a digested Dictionary. | ||
* Faster startup than ZSTD_decompress_usingDict(), recommended when same dictionary is used multiple times. */ | ||||
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r30434 | 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. | ||||
* | ||||
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r40157 | * Start a new compression by initializing ZSTD_CStream context. | ||
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r30434 | * Use ZSTD_initCStream() to start a new compression operation. | ||
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r40157 | * Use variants ZSTD_initCStream_usingDict() or ZSTD_initCStream_usingCDict() for streaming with dictionary (experimental section) | ||
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r30434 | * | ||
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r40157 | * Use ZSTD_compressStream() as many times as necessary to consume input stream. | ||
* The function will automatically update both `pos` fields within `input` and `output`. | ||||
* Note that the function may not consume the entire input, | ||||
* for example, because the output buffer is already full, | ||||
* in which case `input.pos < input.size`. | ||||
* The caller must check if input has been entirely consumed. | ||||
* If not, the caller must make some room to receive more compressed data, | ||||
* typically by emptying output buffer, or allocating a new output buffer, | ||||
* and then present again remaining input data. | ||||
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r30434 | * @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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r40157 | * At any moment, it's possible to flush whatever data might remain stuck within internal buffer, | ||
* using ZSTD_flushStream(). `output->pos` will be updated. | ||||
* Note that, if `output->size` is too small, a single invocation of ZSTD_flushStream() might not be enough (return code > 0). | ||||
* In which case, make some room to receive more compressed data, and call again ZSTD_flushStream(). | ||||
* @return : 0 if internal buffers are entirely flushed, | ||||
* >0 if some data still present within internal buffer (the value is minimal estimation of remaining size), | ||||
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r30434 | * 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. | ||||
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r40157 | * flush() operation is the same, and follows same rules as ZSTD_flushStream(). | ||
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r37513 | * @return : 0 if frame fully completed and fully flushed, | ||
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r40157 | * >0 if some data still present within internal buffer (the value is minimal estimation of remaining size), | ||
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r30434 | * or an error code, which can be tested using ZSTD_isError(). | ||
* | ||||
* *******************************************************************/ | ||||
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r37513 | typedef ZSTD_CCtx ZSTD_CStream; /**< CCtx and CStream are now effectively same object (>= v1.3.0) */ | ||
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r40157 | /* Continue to distinguish them for compatibility with older versions <= v1.2.0 */ | ||
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r37513 | /*===== ZSTD_CStream management functions =====*/ | ||
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r30434 | 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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r37513 | /*===== Streaming compression functions =====*/ | ||
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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 | * *******************************************************************************/ | ||
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r37513 | typedef ZSTD_DCtx ZSTD_DStream; /**< DCtx and DStream are now effectively same object (>= v1.3.0) */ | ||
/* For compatibility with versions <= v1.2.0, continue to consider them separated. */ | ||||
/*===== ZSTD_DStream management functions =====*/ | ||||
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r30434 | 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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r37513 | /*===== Streaming decompression functions =====*/ | ||
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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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r40157 | |||
#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 | /**************************************************************************************** | ||
|
r40157 | * ADVANCED AND EXPERIMENTAL FUNCTIONS | ||
**************************************************************************************** | ||||
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r30434 | * The definitions in this section are considered experimental. | ||
|
r37513 | * They should never be used with a dynamic library, as prototypes may change in the future. | ||
* They are provided for advanced scenarios. | ||||
|
r30434 | * Use them only in association with static linking. | ||
* ***************************************************************************************/ | ||||
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r40157 | ZSTDLIB_API int ZSTD_minCLevel(void); /*!< minimum negative compression level allowed */ | ||
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r37513 | |||
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r40157 | /* --- Constants ---*/ | ||
#define ZSTD_MAGICNUMBER 0xFD2FB528 /* v0.8+ */ | ||||
#define ZSTD_MAGIC_DICTIONARY 0xEC30A437 /* v0.7+ */ | ||||
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r30434 | #define ZSTD_MAGIC_SKIPPABLE_START 0x184D2A50U | ||
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r40157 | |||
#define ZSTD_BLOCKSIZELOG_MAX 17 | ||||
#define ZSTD_BLOCKSIZE_MAX (1<<ZSTD_BLOCKSIZELOG_MAX) /* define, for static allocation */ | ||||
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r30434 | |||
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r37513 | #define ZSTD_WINDOWLOG_MAX_32 30 | ||
#define ZSTD_WINDOWLOG_MAX_64 31 | ||||
#define ZSTD_WINDOWLOG_MAX ((unsigned)(sizeof(size_t) == 4 ? ZSTD_WINDOWLOG_MAX_32 : ZSTD_WINDOWLOG_MAX_64)) | ||||
#define ZSTD_WINDOWLOG_MIN 10 | ||||
#define ZSTD_HASHLOG_MAX ((ZSTD_WINDOWLOG_MAX < 30) ? ZSTD_WINDOWLOG_MAX : 30) | ||||
#define ZSTD_HASHLOG_MIN 6 | ||||
#define ZSTD_CHAINLOG_MAX_32 29 | ||||
#define ZSTD_CHAINLOG_MAX_64 30 | ||||
#define ZSTD_CHAINLOG_MAX ((unsigned)(sizeof(size_t) == 4 ? ZSTD_CHAINLOG_MAX_32 : ZSTD_CHAINLOG_MAX_64)) | ||||
#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 */ | ||||
|
r40157 | #define ZSTD_TARGETLENGTH_MAX ZSTD_BLOCKSIZE_MAX | ||
#define ZSTD_TARGETLENGTH_MIN 0 /* note : comparing this constant to an unsigned results in a tautological test */ | ||||
#define ZSTD_LDM_MINMATCH_MAX 4096 | ||||
|
r37513 | #define ZSTD_LDM_MINMATCH_MIN 4 | ||
#define ZSTD_LDM_BUCKETSIZELOG_MAX 8 | ||||
|
r30434 | |||
|
r37513 | #define ZSTD_FRAMEHEADERSIZE_PREFIX 5 /* minimum input size to know frame header size */ | ||
#define ZSTD_FRAMEHEADERSIZE_MIN 6 | ||||
#define ZSTD_FRAMEHEADERSIZE_MAX 18 /* for static allocation */ | ||||
static const size_t ZSTD_frameHeaderSize_prefix = ZSTD_FRAMEHEADERSIZE_PREFIX; | ||||
|
r30895 | static const size_t ZSTD_frameHeaderSize_min = ZSTD_FRAMEHEADERSIZE_MIN; | ||
|
r30434 | static const size_t ZSTD_frameHeaderSize_max = ZSTD_FRAMEHEADERSIZE_MAX; | ||
static const size_t ZSTD_skippableHeaderSize = 8; /* magic number + skippable frame length */ | ||||
|
r40157 | |||
/* --- Advanced types --- */ | ||||
|
r37513 | 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 */ | ||||
|
r30434 | |||
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 { | ||||
|
r30895 | unsigned contentSizeFlag; /**< 1: content size will be in frame header (when known) */ | ||
unsigned checksumFlag; /**< 1: generate a 32-bits checksum at end of frame, for error detection */ | ||||
unsigned noDictIDFlag; /**< 1: no dictID will be saved into frame header (if dictionary compression) */ | ||||
|
r30434 | } ZSTD_frameParameters; | ||
typedef struct { | ||||
ZSTD_compressionParameters cParams; | ||||
ZSTD_frameParameters fParams; | ||||
} ZSTD_parameters; | ||||
|
r37513 | typedef struct ZSTD_CCtx_params_s ZSTD_CCtx_params; | ||
typedef enum { | ||||
ZSTD_dct_auto=0, /* dictionary is "full" when starting with ZSTD_MAGIC_DICTIONARY, otherwise it is "rawContent" */ | ||||
ZSTD_dct_rawContent, /* ensures dictionary is always loaded as rawContent, even if it starts with ZSTD_MAGIC_DICTIONARY */ | ||||
ZSTD_dct_fullDict /* refuses to load a dictionary if it does not respect Zstandard's specification */ | ||||
} ZSTD_dictContentType_e; | ||||
typedef enum { | ||||
ZSTD_dlm_byCopy = 0, /**< Copy dictionary content internally */ | ||||
ZSTD_dlm_byRef, /**< Reference dictionary content -- the dictionary buffer must outlive its users. */ | ||||
} ZSTD_dictLoadMethod_e; | ||||
/*************************************** | ||||
* Frame size functions | ||||
***************************************/ | ||||
/*! ZSTD_findFrameCompressedSize() : | ||||
* `src` should point to the start of a ZSTD encoded frame or skippable frame | ||||
* `srcSize` must be >= first frame size | ||||
* @return : the compressed size of the first frame starting at `src`, | ||||
* suitable to pass to `ZSTD_decompress` or similar, | ||||
* or an error code if input is invalid */ | ||||
ZSTDLIB_API size_t ZSTD_findFrameCompressedSize(const void* src, size_t srcSize); | ||||
/*! 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 | ||||
* | ||||
* note 1 : decompressed size is an optional field, that may not be present, especially in streaming mode. | ||||
* When `return==ZSTD_CONTENTSIZE_UNKNOWN`, data to decompress could be any size. | ||||
* In which case, it's necessary to use streaming mode to decompress data. | ||||
* 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 : ZSTD_findDecompressedSize handles multiple frames, and so it must traverse the input to | ||||
* read each contained frame header. This is fast as most of the data is skipped, | ||||
* however it does mean that all frame data must be present and valid. */ | ||||
ZSTDLIB_API unsigned long long ZSTD_findDecompressedSize(const void* src, size_t srcSize); | ||||
/*! ZSTD_frameHeaderSize() : | ||||
|
r40157 | * srcSize must be >= ZSTD_frameHeaderSize_prefix. | ||
* @return : size of the Frame Header, | ||||
* or an error code (if srcSize is too small) */ | ||||
|
r37513 | ZSTDLIB_API size_t ZSTD_frameHeaderSize(const void* src, size_t srcSize); | ||
/*************************************** | ||||
* Memory management | ||||
***************************************/ | ||||
/*! ZSTD_sizeof_*() : | ||||
* These functions give the current memory usage of selected object. | ||||
* Object memory usage can evolve when re-used. */ | ||||
ZSTDLIB_API size_t ZSTD_sizeof_CCtx(const ZSTD_CCtx* cctx); | ||||
ZSTDLIB_API size_t ZSTD_sizeof_DCtx(const ZSTD_DCtx* dctx); | ||||
ZSTDLIB_API size_t ZSTD_sizeof_CStream(const ZSTD_CStream* zcs); | ||||
ZSTDLIB_API size_t ZSTD_sizeof_DStream(const ZSTD_DStream* zds); | ||||
ZSTDLIB_API size_t ZSTD_sizeof_CDict(const ZSTD_CDict* cdict); | ||||
ZSTDLIB_API size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict); | ||||
/*! 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_p_nbWorkers is >= 1. | ||||
* Note : CCtx size estimation is only correct for single-threaded compression. */ | ||||
ZSTDLIB_API size_t ZSTD_estimateCCtxSize(int compressionLevel); | ||||
ZSTDLIB_API size_t ZSTD_estimateCCtxSize_usingCParams(ZSTD_compressionParameters cParams); | ||||
ZSTDLIB_API size_t ZSTD_estimateCCtxSize_usingCCtxParams(const ZSTD_CCtx_params* params); | ||||
ZSTDLIB_API size_t ZSTD_estimateDCtxSize(void); | ||||
/*! 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_p_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 */ | ||||
ZSTDLIB_API size_t ZSTD_estimateCStreamSize(int compressionLevel); | ||||
ZSTDLIB_API size_t ZSTD_estimateCStreamSize_usingCParams(ZSTD_compressionParameters cParams); | ||||
ZSTDLIB_API size_t ZSTD_estimateCStreamSize_usingCCtxParams(const ZSTD_CCtx_params* params); | ||||
ZSTDLIB_API size_t ZSTD_estimateDStreamSize(size_t windowSize); | ||||
ZSTDLIB_API size_t ZSTD_estimateDStreamSize_fromFrame(const void* src, size_t srcSize); | ||||
/*! 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. | ||||
*/ | ||||
ZSTDLIB_API size_t ZSTD_estimateCDictSize(size_t dictSize, int compressionLevel); | ||||
ZSTDLIB_API size_t ZSTD_estimateCDictSize_advanced(size_t dictSize, ZSTD_compressionParameters cParams, ZSTD_dictLoadMethod_e dictLoadMethod); | ||||
ZSTDLIB_API size_t ZSTD_estimateDDictSize(size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod); | ||||
/*! 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. | ||||
*/ | ||||
ZSTDLIB_API ZSTD_CCtx* ZSTD_initStaticCCtx(void* workspace, size_t workspaceSize); | ||||
ZSTDLIB_API ZSTD_CStream* ZSTD_initStaticCStream(void* workspace, size_t workspaceSize); /**< same as ZSTD_initStaticCCtx() */ | ||||
ZSTDLIB_API ZSTD_DCtx* ZSTD_initStaticDCtx(void* workspace, size_t workspaceSize); | ||||
ZSTDLIB_API ZSTD_DStream* ZSTD_initStaticDStream(void* workspace, size_t workspaceSize); /**< same as ZSTD_initStaticDCtx() */ | ||||
ZSTDLIB_API const ZSTD_CDict* ZSTD_initStaticCDict( | ||||
void* workspace, size_t workspaceSize, | ||||
const void* dict, size_t dictSize, | ||||
ZSTD_dictLoadMethod_e dictLoadMethod, | ||||
ZSTD_dictContentType_e dictContentType, | ||||
ZSTD_compressionParameters cParams); | ||||
ZSTDLIB_API const ZSTD_DDict* ZSTD_initStaticDDict( | ||||
void* workspace, size_t workspaceSize, | ||||
const void* dict, size_t dictSize, | ||||
ZSTD_dictLoadMethod_e dictLoadMethod, | ||||
ZSTD_dictContentType_e dictContentType); | ||||
/*! 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. | ||||
*/ | ||||
|
r30434 | 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; | ||||
|
r37513 | static ZSTD_customMem const ZSTD_defaultCMem = { NULL, NULL, NULL }; /**< this constant defers to stdlib's functions */ | ||
ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem); | ||||
ZSTDLIB_API ZSTD_CStream* ZSTD_createCStream_advanced(ZSTD_customMem customMem); | ||||
ZSTDLIB_API ZSTD_DCtx* ZSTD_createDCtx_advanced(ZSTD_customMem customMem); | ||||
ZSTDLIB_API ZSTD_DStream* ZSTD_createDStream_advanced(ZSTD_customMem customMem); | ||||
ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_advanced(const void* dict, size_t dictSize, | ||||
ZSTD_dictLoadMethod_e dictLoadMethod, | ||||
ZSTD_dictContentType_e dictContentType, | ||||
ZSTD_compressionParameters cParams, | ||||
ZSTD_customMem customMem); | ||||
ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict_advanced(const void* dict, size_t dictSize, | ||||
ZSTD_dictLoadMethod_e dictLoadMethod, | ||||
ZSTD_dictContentType_e dictContentType, | ||||
ZSTD_customMem customMem); | ||||
|
r30434 | |||
/*************************************** | ||||
* Advanced compression functions | ||||
***************************************/ | ||||
|
r30895 | |||
/*! 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); | ||||
|
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); | ||||
|
r30434 | |||
|
r30822 | /*! ZSTD_getParams() : | ||
* same as ZSTD_getCParams(), but @return a full `ZSTD_parameters` object instead of sub-component `ZSTD_compressionParameters`. | ||||
|
r37513 | * All fields of `ZSTD_frameParameters` are set to default : contentSize=1, checksum=0, noDictID=0 */ | ||
|
r30822 | ZSTDLIB_API ZSTD_parameters ZSTD_getParams(int compressionLevel, unsigned long long estimatedSrcSize, size_t dictSize); | ||
|
r30434 | |||
/*! ZSTD_checkCParams() : | ||||
* Ensure param values remain within authorized range */ | ||||
ZSTDLIB_API size_t ZSTD_checkCParams(ZSTD_compressionParameters params); | ||||
/*! ZSTD_adjustCParams() : | ||||
|
r37513 | * optimize params for a given `srcSize` and `dictSize`. | ||
* both values are optional, select `0` if unknown. */ | ||||
|
r30434 | ZSTDLIB_API ZSTD_compressionParameters ZSTD_adjustCParams(ZSTD_compressionParameters cPar, unsigned long long srcSize, size_t dictSize); | ||
/*! ZSTD_compress_advanced() : | ||||
|
r37513 | * Same as ZSTD_compress_usingDict(), with fine-tune control over each compression parameter */ | ||
ZSTDLIB_API size_t ZSTD_compress_advanced (ZSTD_CCtx* cctx, | ||||
void* dst, size_t dstCapacity, | ||||
const void* src, size_t srcSize, | ||||
const void* dict,size_t dictSize, | ||||
ZSTD_parameters params); | ||||
/*! ZSTD_compress_usingCDict_advanced() : | ||||
* Same as ZSTD_compress_usingCDict(), with fine-tune control over frame parameters */ | ||||
ZSTDLIB_API size_t ZSTD_compress_usingCDict_advanced(ZSTD_CCtx* cctx, | ||||
void* dst, size_t dstCapacity, | ||||
const void* src, size_t srcSize, | ||||
const ZSTD_CDict* cdict, ZSTD_frameParameters fParams); | ||||
|
r30434 | |||
/*--- Advanced decompression functions ---*/ | ||||
|
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); | ||||
|
r30895 | /*! ZSTD_createDDict_byReference() : | ||
* Create a digested dictionary, ready to start decompression operation without startup delay. | ||||
|
r37513 | * 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 */ | ||||
|
r30895 | ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict_byReference(const void* dictBuffer, size_t dictSize); | ||
|
r30434 | |||
|
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. */ | ||||
|
r30895 | ZSTDLIB_API unsigned ZSTD_getDictID_fromDict(const void* dict, size_t dictSize); | ||
|
r30822 | |||
/*! 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. */ | ||||
|
r30895 | ZSTDLIB_API unsigned ZSTD_getDictID_fromDDict(const ZSTD_DDict* ddict); | ||
|
r30822 | |||
/*! 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. | ||||
|
r37513 | * When identifying the exact failure cause, it's possible to use ZSTD_getFrameHeader(), which will provide a more precise error code. */ | ||
|
r30895 | ZSTDLIB_API unsigned ZSTD_getDictID_fromFrame(const void* src, size_t srcSize); | ||
|
r30822 | |||
|
r30434 | |||
/******************************************************************** | ||||
* Advanced streaming functions | ||||
********************************************************************/ | ||||
/*===== Advanced Streaming compression functions =====*/ | ||||
|
r37513 | ZSTDLIB_API size_t ZSTD_initCStream_srcSize(ZSTD_CStream* zcs, int compressionLevel, unsigned long long pledgedSrcSize); /**< pledgedSrcSize must be correct. If it is not known at init time, use ZSTD_CONTENTSIZE_UNKNOWN. Note that, for compatibility with older programs, "0" also disables frame content size field. It may be enabled in the future. */ | ||
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. Note: dict is loaded with ZSTD_dm_auto (treated as a full zstd dictionary if it begins with ZSTD_MAGIC_DICTIONARY, else as raw content) and ZSTD_dlm_byCopy.*/ | ||||
|
r30434 | ZSTDLIB_API size_t ZSTD_initCStream_advanced(ZSTD_CStream* zcs, const void* dict, size_t dictSize, | ||
|
r37513 | ZSTD_parameters params, unsigned long long pledgedSrcSize); /**< pledgedSrcSize must be correct. If srcSize is not known at init time, use value ZSTD_CONTENTSIZE_UNKNOWN. dict is loaded with ZSTD_dm_auto and ZSTD_dlm_byCopy. */ | ||
|
r30434 | 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 */ | ||
|
r37513 | 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. pledgedSrcSize must be correct. If srcSize is not known at init time, use value ZSTD_CONTENTSIZE_UNKNOWN. */ | ||
/*! ZSTD_resetCStream() : | ||||
* start a new compression job, using same parameters from previous job. | ||||
|
r40157 | * This is typically useful to skip dictionary loading stage, since it will re-use it in-place. | ||
|
r37513 | * 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. | ||||
|
r40157 | * @return : 0, or an error code (which can be tested using ZSTD_isError()) | ||
*/ | ||||
|
r37513 | ZSTDLIB_API size_t ZSTD_resetCStream(ZSTD_CStream* zcs, unsigned long long pledgedSrcSize); | ||
typedef struct { | ||||
|
r40157 | unsigned long long ingested; /* nb input bytes read and buffered */ | ||
unsigned long long consumed; /* nb input bytes actually compressed */ | ||||
unsigned long long produced; /* nb of compressed bytes generated and buffered */ | ||||
unsigned long long flushed; /* nb of compressed bytes flushed : not provided; can be tracked from caller side */ | ||||
unsigned currentJobID; /* MT only : latest started job nb */ | ||||
unsigned nbActiveWorkers; /* MT only : nb of workers actively compressing at probe time */ | ||||
|
r37513 | } ZSTD_frameProgression; | ||
|
r40157 | /* ZSTD_getFrameProgression() : | ||
|
r37513 | * tells how much data has been ingested (read from input) | ||
* consumed (input actually compressed) and produced (output) for current frame. | ||||
|
r40157 | * Note : (ingested - consumed) is amount of input data buffered internally, not yet compressed. | ||
* Aggregates progression inside active worker threads. | ||||
|
r37513 | */ | ||
|
r40157 | ZSTDLIB_API ZSTD_frameProgression ZSTD_getFrameProgression(const ZSTD_CCtx* cctx); | ||
/*! 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 : | ||||
* + there is no active job (could be checked with ZSTD_frameProgression()), or | ||||
* + oldest job is still actively compressing data, | ||||
* but everything it has produced has also been flushed so far, | ||||
* therefore flushing speed is currently limited by production speed of oldest job | ||||
* irrespective of the speed of concurrent newer jobs. | ||||
*/ | ||||
ZSTDLIB_API size_t ZSTD_toFlushNow(ZSTD_CCtx* cctx); | ||||
|
r37513 | |||
|
r30434 | |||
/*===== Advanced Streaming decompression functions =====*/ | ||||
|
r30895 | typedef enum { DStream_p_maxWindowSize } ZSTD_DStreamParameter_e; | ||
|
r37513 | ZSTDLIB_API size_t ZSTD_setDStreamParameter(ZSTD_DStream* zds, ZSTD_DStreamParameter_e paramType, unsigned paramValue); /* obsolete : this API will be removed in a future version */ | ||
ZSTDLIB_API size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize); /**< note: no dictionary will be used if dict == NULL or dictSize < 8 */ | ||||
ZSTDLIB_API size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* zds, const ZSTD_DDict* ddict); /**< note : ddict is referenced, it must outlive decompression session */ | ||||
|
r30434 | ZSTDLIB_API size_t ZSTD_resetDStream(ZSTD_DStream* zds); /**< re-use decompression parameters from previous init; saves dictionary loading */ | ||
/********************************************************************* | ||||
* 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. | ||||
|
r37513 | * But it's also a complex one, with several restrictions, documented below. | ||
* Prefer normal streaming API for an easier experience. | ||||
|
r30434 | ********************************************************************* */ | ||
/** | ||||
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 : | ||||
|
r37513 | - ZSTD_compressContinue() has no internal buffer. It uses externally provided buffers only. | ||
- Interface is synchronous : input is consumed entirely and produces 1+ compressed blocks. | ||||
|
r30434 | - 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. | ||||
|
r30895 | It's possible to use srcSize==0, in which case, it will write a final empty block to end the frame. | ||
|
r37513 | Without last block mark, frames are considered unfinished (hence corrupted) by compliant decoders. | ||
|
r30434 | |||
|
r37513 | `ZSTD_CCtx` object can be re-used (ZSTD_compressBegin()) to compress again. | ||
|
r30434 | */ | ||
/*===== 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); | ||||
|
r37513 | ZSTDLIB_API size_t ZSTD_compressBegin_advanced(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, ZSTD_parameters params, unsigned long long pledgedSrcSize); /**< pledgedSrcSize : If srcSize is not known at init time, use ZSTD_CONTENTSIZE_UNKNOWN */ | ||
ZSTDLIB_API size_t ZSTD_compressBegin_usingCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict); /**< note: fails if cdict==NULL */ | ||||
ZSTDLIB_API size_t ZSTD_compressBegin_usingCDict_advanced(ZSTD_CCtx* const cctx, const ZSTD_CDict* const cdict, ZSTD_frameParameters const fParams, unsigned long long const pledgedSrcSize); /* compression parameters are already set within cdict. pledgedSrcSize must be correct. If srcSize is not known, use macro ZSTD_CONTENTSIZE_UNKNOWN */ | ||||
ZSTDLIB_API size_t ZSTD_copyCCtx(ZSTD_CCtx* cctx, const ZSTD_CCtx* preparedCCtx, unsigned long long pledgedSrcSize); /**< note: if pledgedSrcSize is not known, use ZSTD_CONTENTSIZE_UNKNOWN */ | ||||
|
r30434 | 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. | ||||
|
r37513 | First typical operation is to retrieve frame parameters, using ZSTD_getFrameHeader(). | ||
Frame header is extracted from the beginning of compressed frame, so providing only the frame's beginning is enough. | ||||
Data fragment must be large enough to ensure successful decoding. | ||||
`ZSTD_frameHeaderSize_max` bytes is guaranteed to always be large enough. | ||||
@result : 0 : successful decoding, the `ZSTD_frameHeader` structure is correctly filled. | ||||
|
r30434 | >0 : `srcSize` is too small, please provide at least @result bytes on next attempt. | ||
errorCode, which can be tested using ZSTD_isError(). | ||||
|
r37513 | It fills a ZSTD_frameHeader structure with important information to correctly decode the frame, | ||
such as the dictionary ID, content size, or maximum back-reference distance (`windowSize`). | ||||
Note that these values could be wrong, either because of data corruption, or because a 3rd party deliberately spoofs false information. | ||||
As a consequence, check that values remain within valid application range. | ||||
For example, do not allocate memory blindly, check that `windowSize` is within expectation. | ||||
Each application can set its own limits, depending on local restrictions. | ||||
For extended interoperability, it is recommended to support `windowSize` of at least 8 MB. | ||||
ZSTD_decompressContinue() needs previous data blocks during decompression, up to `windowSize` bytes. | ||||
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 distance. | ||||
There are multiple ways to guarantee this condition. | ||||
The most memory efficient way is to use a round buffer of sufficient size. | ||||
Sufficient size is determined by invoking ZSTD_decodingBufferSize_min(), | ||||
which can @return an error code if required value is too large for current system (in 32-bits mode). | ||||
In a round buffer methodology, ZSTD_decompressContinue() decompresses each block next to previous one, | ||||
up to the moment there is not enough room left in the buffer to guarantee decoding another full block, | ||||
which maximum size is provided in `ZSTD_frameHeader` structure, field `blockSizeMax`. | ||||
At which point, decoding can resume from the beginning of the buffer. | ||||
Note that already decoded data stored in the buffer should be flushed before being overwritten. | ||||
There are alternatives possible, for example using two or more buffers of size `windowSize` each, though they consume more memory. | ||||
Finally, if you control the compression process, you can also ignore all buffer size rules, | ||||
as long as the encoder and decoder progress in "lock-step", | ||||
aka use exactly the same buffer sizes, break contiguity at the same place, etc. | ||||
Once buffers are setup, start decompression, with ZSTD_decompressBegin(). | ||||
If decompression requires a dictionary, use ZSTD_decompressBegin_usingDict() or ZSTD_decompressBegin_usingDDict(). | ||||
|
r30434 | |||
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. | ||||
|
r37513 | @result of ZSTD_decompressContinue() is the number of bytes regenerated within 'dst' (necessarily <= dstCapacity). | ||
It can be zero : it just means ZSTD_decompressContinue() has decoded some metadata item. | ||||
|
r30434 | It can also be an error code, which can be tested with ZSTD_isError(). | ||
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. | ||||
|
r37513 | Skippable frames will be ignored (skipped) by decompressor. | ||
The format of skippable frames is as follows : | ||||
|
r30434 | 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 | ||||
|
r37513 | For skippable frames ZSTD_getFrameHeader() returns zfhPtr->frameType==ZSTD_skippableFrame. | ||
For skippable frames ZSTD_decompressContinue() always returns 0 : it only skips the content. | ||||
|
r30434 | */ | ||
|
r37513 | /*===== Buffer-less streaming decompression functions =====*/ | ||
typedef enum { ZSTD_frame, ZSTD_skippableFrame } ZSTD_frameType_e; | ||||
|
r30434 | typedef struct { | ||
|
r37513 | unsigned long long frameContentSize; /* if == ZSTD_CONTENTSIZE_UNKNOWN, it means this field is not available. 0 means "empty" */ | ||
unsigned long long windowSize; /* can be very large, up to <= frameContentSize */ | ||||
unsigned blockSizeMax; | ||||
ZSTD_frameType_e frameType; /* if == ZSTD_skippableFrame, frameContentSize is the size of skippable content */ | ||||
unsigned headerSize; | ||||
|
r30434 | unsigned dictID; | ||
unsigned checksumFlag; | ||||
|
r37513 | } ZSTD_frameHeader; | ||
|
r40157 | /** 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() */ | ||||
|
r37513 | ZSTDLIB_API size_t ZSTD_getFrameHeader(ZSTD_frameHeader* zfhPtr, const void* src, size_t srcSize); /**< doesn't consume input */ | ||
ZSTDLIB_API size_t ZSTD_decodingBufferSize_min(unsigned long long windowSize, unsigned long long frameContentSize); /**< when frame content size is not known, pass in frameContentSize == ZSTD_CONTENTSIZE_UNKNOWN */ | ||||
|
r30434 | |||
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); | ||||
|
r37513 | ZSTDLIB_API size_t ZSTD_decompressBegin_usingDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict); | ||
|
r30434 | 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); | ||||
|
r37513 | |||
/* misc */ | ||||
ZSTDLIB_API void ZSTD_copyDCtx(ZSTD_DCtx* dctx, const ZSTD_DCtx* preparedDCtx); | ||||
|
r30434 | 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); | ||||
|
r37513 | |||
/* ============================================ */ | ||||
/** New advanced API (experimental) */ | ||||
/* ============================================ */ | ||||
|
r40157 | /* API design : | ||
* In this advanced API, parameters are pushed one by one into an existing context, | ||||
* using ZSTD_CCtx_set*() functions. | ||||
* Pushed parameters are sticky : they are applied to next job, and any subsequent job. | ||||
* It's possible to reset parameters to "default" using ZSTD_CCtx_reset(). | ||||
* Important : "sticky" parameters only work with `ZSTD_compress_generic()` ! | ||||
* For any other entry point, "sticky" parameters are ignored ! | ||||
|
r37513 | * | ||
* This API is intended to replace all others advanced / experimental API entry points. | ||||
*/ | ||||
/* note on enum design : | ||||
* All enum will be pinned to explicit values before reaching "stable API" status */ | ||||
typedef enum { | ||||
/* Opened question : should we have a format ZSTD_f_auto ? | ||||
* Today, it would mean exactly the same as ZSTD_f_zstd1. | ||||
* But, in the future, should several formats become supported, | ||||
* on the compression side, it would mean "default format". | ||||
* On the decompression side, it would mean "automatic format detection", | ||||
* so that ZSTD_f_zstd1 would mean "accept *only* zstd frames". | ||||
* Since meaning is a little different, another option could be to define different enums for compression and decompression. | ||||
* This question could be kept for later, when there are actually multiple formats to support, | ||||
* but there is also the question of pinning enum values, and pinning value `0` is especially important */ | ||||
ZSTD_f_zstd1 = 0, /* zstd frame format, specified in zstd_compression_format.md (default) */ | ||||
ZSTD_f_zstd1_magicless, /* Variant of zstd frame format, without initial 4-bytes magic number. | ||||
* Useful to save 4 bytes per generated frame. | ||||
* Decoder cannot recognise automatically this format, requiring instructions. */ | ||||
} ZSTD_format_e; | ||||
typedef enum { | ||||
/* compression format */ | ||||
ZSTD_p_format = 10, /* See ZSTD_format_e enum definition. | ||||
* Cast selected format as unsigned for ZSTD_CCtx_setParameter() compatibility. */ | ||||
/* compression parameters */ | ||||
ZSTD_p_compressionLevel=100, /* Update all compression parameters according to pre-defined cLevel table | ||||
* Default level is ZSTD_CLEVEL_DEFAULT==3. | ||||
|
r40157 | * Special: value 0 means default, which is controlled by ZSTD_CLEVEL_DEFAULT. | ||
|
r37513 | * Note 1 : it's possible to pass a negative compression level by casting it to unsigned type. | ||
* Note 2 : setting a level sets all default values of other compression parameters. | ||||
* Note 3 : setting compressionLevel automatically updates ZSTD_p_compressLiterals. */ | ||||
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 "use default windowLog". | ||||
* Note: Using a window size greater than ZSTD_MAXWINDOWSIZE_DEFAULT (default: 2^27) | ||||
* requires explicitly allowing such window size during decompression stage. */ | ||||
|
r40157 | ZSTD_p_hashLog, /* Size of the initial probe table, as a power of 2. | ||
|
r37513 | * 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 "use default hashLog". */ | ||||
|
r40157 | ZSTD_p_chainLog, /* Size of the multi-probe search table, as a power of 2. | ||
|
r37513 | * Resulting table size is (1 << (chainLog+2)). | ||
|
r40157 | * Must be clamped between ZSTD_CHAINLOG_MIN and ZSTD_CHAINLOG_MAX. | ||
|
r37513 | * Larger tables result in better and slower compression. | ||
* This parameter is useless when using "fast" strategy. | ||||
|
r40157 | * Note it's still useful when using "dfast" strategy, | ||
* in which case it defines a secondary probe table. | ||||
|
r37513 | * Special: value 0 means "use default 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 "use default 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. | ||||
* , for all strategies > fast, effective maximum is 6. | ||||
* Special: value 0 means "use default minMatchLength". */ | ||||
ZSTD_p_targetLength, /* Impact of this field depends on strategy. | ||||
* For strategies btopt & btultra: | ||||
* Length of Match considered "good enough" to stop search. | ||||
* Larger values make compression stronger, and slower. | ||||
* For strategy fast: | ||||
* Distance between match sampling. | ||||
* Larger values make compression faster, and weaker. | ||||
* Special: value 0 means "use default 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 "use default strategy". */ | ||||
ZSTD_p_enableLongDistanceMatching=160, /* Enable long distance matching. | ||||
* This parameter is designed to improve compression ratio | ||||
* for large inputs, by finding large matches at long distance. | ||||
* It increases memory usage and window size. | ||||
* Note: enabling this parameter increases ZSTD_p_windowLog to 128 MB | ||||
* except when expressly set to a different value. */ | ||||
ZSTD_p_ldmHashLog, /* Size of the table for long distance matching, as a power of 2. | ||||
* Larger values increase memory usage and compression ratio, | ||||
* but decrease compression speed. | ||||
* Must be clamped between ZSTD_HASHLOG_MIN and ZSTD_HASHLOG_MAX | ||||
* default: windowlog - 7. | ||||
* Special: value 0 means "automatically determine hashlog". */ | ||||
ZSTD_p_ldmMinMatch, /* Minimum match size for long distance matcher. | ||||
* Larger/too small values usually decrease compression ratio. | ||||
* Must be clamped between ZSTD_LDM_MINMATCH_MIN and ZSTD_LDM_MINMATCH_MAX. | ||||
* Special: value 0 means "use default value" (default: 64). */ | ||||
ZSTD_p_ldmBucketSizeLog, /* Log size of each bucket in the LDM hash table for collision resolution. | ||||
* Larger values improve collision resolution but decrease compression speed. | ||||
* The maximum value is ZSTD_LDM_BUCKETSIZELOG_MAX . | ||||
* Special: value 0 means "use default value" (default: 3). */ | ||||
ZSTD_p_ldmHashEveryLog, /* Frequency of inserting/looking up entries in the LDM hash table. | ||||
* Must be clamped between 0 and (ZSTD_WINDOWLOG_MAX - ZSTD_HASHLOG_MIN). | ||||
* Default is MAX(0, (windowLog - ldmHashLog)), optimizing hash table usage. | ||||
* Larger values improve compression speed. | ||||
* Deviating far from default value will likely result in a compression ratio decrease. | ||||
* Special: value 0 means "automatically determine hashEveryLog". */ | ||||
/* frame parameters */ | ||||
ZSTD_p_contentSizeFlag=200, /* Content size will be written into frame header _whenever known_ (default:1) | ||||
* Content size must be known at the beginning of compression, | ||||
* it is provided using ZSTD_CCtx_setPledgedSrcSize() */ | ||||
ZSTD_p_checksumFlag, /* A 32-bits checksum of content is written at end of frame (default:0) */ | ||||
ZSTD_p_dictIDFlag, /* When applicable, dictionary's ID is written into frame header (default:1) */ | ||||
/* multi-threading parameters */ | ||||
/* These parameters are only useful if multi-threading is enabled (ZSTD_MULTITHREAD). | ||||
* They return an error otherwise. */ | ||||
ZSTD_p_nbWorkers=400, /* Select how many threads will be spawned to compress in parallel. | ||||
* When nbWorkers >= 1, triggers asynchronous mode : | ||||
* ZSTD_compress_generic() consumes some input, flush some output if possible, and immediately gives back control to caller, | ||||
* while compression work is performed in parallel, within worker threads. | ||||
* (note : a strong exception to this rule is when first invocation sets ZSTD_e_end : it becomes a blocking call). | ||||
* More workers improve speed, but also increase memory usage. | ||||
* Default value is `0`, aka "single-threaded mode" : no worker is spawned, compression is performed inside Caller's thread, all invocations are blocking */ | ||||
ZSTD_p_jobSize, /* Size of a compression job. This value is enforced only in non-blocking mode. | ||||
* Each compression job is completed in parallel, so this value indirectly controls the nb of active threads. | ||||
* 0 means default, which is dynamically determined based on compression parameters. | ||||
* Job size must be a minimum of overlapSize, or 1 MB, 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 */ | ||||
/* =================================================================== */ | ||||
/* experimental parameters - no stability guaranteed */ | ||||
/* =================================================================== */ | ||||
ZSTD_p_forceMaxWindow=1100, /* Force back-reference distances to remain < windowSize, | ||||
* even when referencing into Dictionary content (default:0) */ | ||||
|
r40157 | ZSTD_p_forceAttachDict, /* ZSTD supports usage of a CDict in-place | ||
* (avoiding having to copy the compression tables | ||||
* from the CDict into the working context). Using | ||||
* a CDict in this way saves an initial setup step, | ||||
* but comes at the cost of more work per byte of | ||||
* input. ZSTD has a simple internal heuristic that | ||||
* guesses which strategy will be faster. You can | ||||
* use this flag to override that guess. | ||||
* | ||||
* Note that the by-reference, in-place strategy is | ||||
* only used when reusing a compression context | ||||
* with compatible compression parameters. (If | ||||
* incompatible / uninitialized, the working | ||||
* context needs to be cleared anyways, which is | ||||
* about as expensive as overwriting it with the | ||||
* dictionary context, so there's no savings in | ||||
* using the CDict by-ref.) | ||||
* | ||||
* Values greater than 0 force attaching the dict. | ||||
* Values less than 0 force copying the dict. | ||||
* 0 selects the default heuristic-guided behavior. | ||||
*/ | ||||
|
r37513 | |||
} ZSTD_cParameter; | ||||
/*! ZSTD_CCtx_setParameter() : | ||||
* Set one compression parameter, selected by enum ZSTD_cParameter. | ||||
|
r40157 | * Setting a parameter is generally only possible during frame initialization (before starting compression). | ||
* Exception : when using multi-threading mode (nbThreads >= 1), | ||||
* following parameters can be updated _during_ compression (within same frame): | ||||
* => compressionLevel, hashLog, chainLog, searchLog, minMatch, targetLength and strategy. | ||||
* new parameters will be active on next job, or after a flush(). | ||||
* Note : when `value` type is not unsigned (int, or enum), cast it to unsigned for proper type checking. | ||||
* @result : informational value (typically, value being set, correctly clamped), | ||||
|
r37513 | * 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); | ||||
|
r40157 | /*! 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()). | ||||
*/ | ||||
ZSTDLIB_API size_t ZSTD_CCtx_getParameter(ZSTD_CCtx* cctx, ZSTD_cParameter param, unsigned* value); | ||||
|
r37513 | /*! 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. | ||||
* ZSTD_CONTENTSIZE_UNKNOWN is default value for any new compression job. | ||||
* 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 dictionary. | ||||
* @result : 0, or an error code (which can be tested with ZSTD_isError()). | ||||
* Special: Adding a NULL (or 0-size) dictionary invalidates previous dictionary, | ||||
* meaning "return to no-dictionary mode". | ||||
* Note 1 : Dictionary will be used for all future compression jobs. | ||||
* To return to "no-dictionary" situation, load a NULL dictionary | ||||
* 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 consuming operation, with non-negligible impact on latency. | ||||
* Note 3 :`dict` content will be copied internally. | ||||
* Use ZSTD_CCtx_loadDictionary_byReference() to reference dictionary 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. */ | ||||
ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary(ZSTD_CCtx* cctx, const void* dict, size_t dictSize); | ||||
ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary_byReference(ZSTD_CCtx* cctx, const void* dict, size_t dictSize); | ||||
ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary_advanced(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_dictContentType_e dictContentType); | ||||
/*! ZSTD_CCtx_refCDict() : | ||||
* Reference 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); | ||||
|
r30434 | |||
|
r37513 | /*! ZSTD_CCtx_refPrefix() : | ||
* Reference a prefix (single-usage dictionary) for next compression job. | ||||
|
r40157 | * 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). | ||||
* Note that prefix is **only used once**. Tables are discarded at end of compression job (ZSTD_e_end). | ||||
|
r37513 | * @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 | ||||
|
r40157 | * Note 1 : Prefix buffer is referenced. It **must** outlive compression job. | ||
* Its contain must remain unmodified up to end of compression (ZSTD_e_end). | ||||
* 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_p_windowLog. | ||||
* Note 3 : Referencing a prefix involves building tables, which are dependent on compression parameters. | ||||
|
r37513 | * It's a CPU consuming operation, with non-negligible impact on latency. | ||
|
r40157 | * If there is a need to use same prefix multiple times, consider loadDictionary instead. | ||
* Note 4 : By default, the prefix is treated as raw content (ZSTD_dm_rawContent). | ||||
|
r37513 | * Use ZSTD_CCtx_refPrefix_advanced() to alter dictMode. */ | ||
|
r40157 | ZSTDLIB_API size_t ZSTD_CCtx_refPrefix(ZSTD_CCtx* cctx, | ||
const void* prefix, size_t prefixSize); | ||||
ZSTDLIB_API size_t ZSTD_CCtx_refPrefix_advanced(ZSTD_CCtx* cctx, | ||||
const void* prefix, size_t prefixSize, | ||||
ZSTD_dictContentType_e dictContentType); | ||||
|
r37513 | |||
/*! 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. | ||||
|
r40157 | * The parameters and dictionary are kept unchanged, to reset them use ZSTD_CCtx_resetParameters(). | ||
|
r37513 | */ | ||
ZSTDLIB_API void ZSTD_CCtx_reset(ZSTD_CCtx* cctx); | ||||
|
r40157 | /*! ZSTD_CCtx_resetParameters() : | ||
* All parameters are back to default values (compression level is ZSTD_CLEVEL_DEFAULT). | ||||
* Dictionary (if any) is dropped. | ||||
* Resetting parameters is only possible during frame initialization (before starting compression). | ||||
* To reset the context use ZSTD_CCtx_reset(). | ||||
* @return 0 or an error code (which can be checked with ZSTD_isError()). | ||||
*/ | ||||
ZSTDLIB_API size_t ZSTD_CCtx_resetParameters(ZSTD_CCtx* cctx); | ||||
|
r37513 | |||
typedef enum { | ||||
ZSTD_e_continue=0, /* collect more data, encoder decides when to output compressed 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 close current frame. Any additional data 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. | ||||
* - outpot->pos must be <= dstCapacity, input->pos must be <= srcSize | ||||
* - outpot->pos and input->pos will be updated. They are guaranteed to remain below their respective limit. | ||||
* - In single-thread mode (default), function is blocking : it completed its job before returning to caller. | ||||
* - In multi-thread mode, function is non-blocking : it just acquires a copy of input, and distribute job to internal worker threads, | ||||
* and then immediately returns, just indicating that there is some data remaining to be flushed. | ||||
* The function nonetheless guarantees forward progress : it will return only after it reads or write at least 1+ byte. | ||||
* - Exception : in multi-threading mode, if the first call requests a ZSTD_e_end directive, it is blocking : it will complete compression before giving back control to caller. | ||||
* - @return provides a minimum amount of data remaining to be flushed from internal buffers | ||||
* or an error code, which can be tested using ZSTD_isError(). | ||||
* if @return != 0, flush is not fully completed, there is still some data left within internal buffers. | ||||
* This is useful for ZSTD_e_flush, since in this case more flushes are necessary to empty all buffers. | ||||
* For ZSTD_e_end, @return == 0 when internal buffers are fully flushed and frame is completed. | ||||
* - after a ZSTD_e_end directive, if internal buffer is not fully flushed (@return != 0), | ||||
* only ZSTD_e_end or ZSTD_e_flush operations are allowed. | ||||
* Before starting a new compression job, or changing compression parameters, | ||||
* it is required to fully flush internal buffers. | ||||
*/ | ||||
ZSTDLIB_API size_t ZSTD_compress_generic (ZSTD_CCtx* cctx, | ||||
ZSTD_outBuffer* output, | ||||
ZSTD_inBuffer* input, | ||||
ZSTD_EndDirective endOp); | ||||
/*! ZSTD_compress_generic_simpleArgs() : | ||||
* Same as ZSTD_compress_generic(), | ||||
* but using only integral types as arguments. | ||||
* Argument list is larger than ZSTD_{in,out}Buffer, | ||||
* but can be helpful for binders from dynamic languages | ||||
* which have troubles handling structures containing memory pointers. | ||||
*/ | ||||
ZSTDLIB_API 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); | ||||
/*! ZSTD_CCtx_params : | ||||
* Quick howto : | ||||
* - ZSTD_createCCtxParams() : Create a ZSTD_CCtx_params structure | ||||
* - ZSTD_CCtxParam_setParameter() : Push parameters one by one into | ||||
* an existing ZSTD_CCtx_params structure. | ||||
* This is similar to | ||||
* ZSTD_CCtx_setParameter(). | ||||
* - ZSTD_CCtx_setParametersUsingCCtxParams() : Apply parameters to | ||||
* an existing CCtx. | ||||
* These parameters will be applied to | ||||
* all subsequent compression jobs. | ||||
* - ZSTD_compress_generic() : Do compression using the CCtx. | ||||
* - ZSTD_freeCCtxParams() : Free the memory. | ||||
* | ||||
* This can be used with ZSTD_estimateCCtxSize_advanced_usingCCtxParams() | ||||
* for static allocation for single-threaded compression. | ||||
*/ | ||||
ZSTDLIB_API ZSTD_CCtx_params* ZSTD_createCCtxParams(void); | ||||
ZSTDLIB_API size_t ZSTD_freeCCtxParams(ZSTD_CCtx_params* params); | ||||
/*! ZSTD_CCtxParams_reset() : | ||||
* Reset params to default values. | ||||
*/ | ||||
ZSTDLIB_API size_t ZSTD_CCtxParams_reset(ZSTD_CCtx_params* params); | ||||
/*! ZSTD_CCtxParams_init() : | ||||
* Initializes the compression parameters of cctxParams according to | ||||
* compression level. All other parameters are reset to their default values. | ||||
*/ | ||||
ZSTDLIB_API size_t ZSTD_CCtxParams_init(ZSTD_CCtx_params* cctxParams, int compressionLevel); | ||||
/*! ZSTD_CCtxParams_init_advanced() : | ||||
* Initializes the compression and frame parameters of cctxParams according to | ||||
* params. All other parameters are reset to their default values. | ||||
*/ | ||||
ZSTDLIB_API size_t ZSTD_CCtxParams_init_advanced(ZSTD_CCtx_params* cctxParams, ZSTD_parameters params); | ||||
/*! 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(). | ||||
* 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_CCtxParam_setParameter(ZSTD_CCtx_params* params, ZSTD_cParameter param, unsigned value); | ||||
|
r40157 | /*! 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()). | ||||
*/ | ||||
ZSTDLIB_API size_t ZSTD_CCtxParam_getParameter(ZSTD_CCtx_params* params, ZSTD_cParameter param, unsigned* value); | ||||
|
r37513 | /*! 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). | ||||
*/ | ||||
ZSTDLIB_API size_t ZSTD_CCtx_setParametersUsingCCtxParams( | ||||
ZSTD_CCtx* cctx, const ZSTD_CCtx_params* params); | ||||
|
r40157 | /* ==================================== */ | ||
/*=== Advanced decompression API ===*/ | ||||
/* ==================================== */ | ||||
|
r37513 | |||
|
r40157 | /* The following API works the same way as the advanced compression API : | ||
* a context is created, parameters are pushed into it one by one, | ||||
* then the context can be used to decompress data using an interface similar to the straming API. | ||||
|
r37513 | */ | ||
/*! ZSTD_DCtx_loadDictionary() : | ||||
* Create an internal DDict from dict buffer, | ||||
* to be used to decompress next frames. | ||||
* @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 : `dict` content will be copied internally. | ||||
* Use ZSTD_DCtx_loadDictionary_byReference() | ||||
* to reference dictionary content instead. | ||||
* In which case, the dictionary buffer must outlive its users. | ||||
* Note 2 : Loading a dictionary involves building tables, | ||||
* which has a non-negligible impact on CPU usage and latency. | ||||
* Note 3 : Use ZSTD_DCtx_loadDictionary_advanced() to select | ||||
* how dictionary content will be interpreted and loaded. | ||||
*/ | ||||
ZSTDLIB_API size_t ZSTD_DCtx_loadDictionary(ZSTD_DCtx* dctx, const void* dict, size_t dictSize); | ||||
ZSTDLIB_API size_t ZSTD_DCtx_loadDictionary_byReference(ZSTD_DCtx* dctx, const void* dict, size_t dictSize); | ||||
ZSTDLIB_API size_t ZSTD_DCtx_loadDictionary_advanced(ZSTD_DCtx* dctx, const void* dict, size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_dictContentType_e dictContentType); | ||||
/*! 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 : adding a NULL DDict means "return to no-dictionary mode". | ||||
* Note 2 : DDict is just referenced, its lifetime must outlive its usage from DCtx. | ||||
*/ | ||||
ZSTDLIB_API size_t ZSTD_DCtx_refDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict); | ||||
/*! ZSTD_DCtx_refPrefix() : | ||||
* Reference a prefix (single-usage dictionary) for next compression job. | ||||
|
r40157 | * 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_DCtx_decompress_generic() returns 0. | ||||
|
r37513 | * @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 | ||||
|
r40157 | * Note 2 : Prefix buffer is referenced. It **must** outlive decompression job. | ||
* Prefix buffer must remain unmodified up to the end of frame, | ||||
* reached when ZSTD_DCtx_decompress_generic() returns 0. | ||||
|
r37513 | * Note 3 : By default, the prefix is treated as raw content (ZSTD_dm_rawContent). | ||
* Use ZSTD_CCtx_refPrefix_advanced() to alter dictMode. | ||||
* Note 4 : Referencing a raw content prefix has almost no cpu nor memory cost. | ||||
|
r40157 | * A fulldict prefix is more costly though. | ||
|
r37513 | */ | ||
|
r40157 | ZSTDLIB_API size_t ZSTD_DCtx_refPrefix(ZSTD_DCtx* dctx, | ||
const void* prefix, size_t prefixSize); | ||||
ZSTDLIB_API size_t ZSTD_DCtx_refPrefix_advanced(ZSTD_DCtx* dctx, | ||||
const void* prefix, size_t prefixSize, | ||||
ZSTD_dictContentType_e dictContentType); | ||||
|
r37513 | |||
/*! ZSTD_DCtx_setMaxWindowSize() : | ||||
* Refuses allocating internal buffers for frames requiring a window size larger than provided limit. | ||||
* This is useful to prevent 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 direct mode. | ||||
* By default, a decompression context accepts all window sizes <= (1 << ZSTD_WINDOWLOG_MAX) | ||||
* @return : 0, or an error code (which can be tested using ZSTD_isError()). | ||||
*/ | ||||
ZSTDLIB_API size_t ZSTD_DCtx_setMaxWindowSize(ZSTD_DCtx* dctx, size_t maxWindowSize); | ||||
/*! 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()). | ||||
*/ | ||||
ZSTDLIB_API size_t ZSTD_DCtx_setFormat(ZSTD_DCtx* dctx, ZSTD_format_e format); | ||||
|
r40157 | /*! ZSTD_getFrameHeader_advanced() : | ||
* same as ZSTD_getFrameHeader(), | ||||
* with added capability to select a format (like ZSTD_f_zstd1_magicless) */ | ||||
ZSTDLIB_API size_t ZSTD_getFrameHeader_advanced(ZSTD_frameHeader* zfhPtr, | ||||
const void* src, size_t srcSize, ZSTD_format_e format); | ||||
|
r37513 | /*! ZSTD_decompress_generic() : | ||
* Behave the same as ZSTD_decompressStream. | ||||
* Decompression parameters cannot be changed once decompression is started. | ||||
* @return : an error code, which can be tested using ZSTD_isError() | ||||
* if >0, a hint, nb of expected input bytes for next invocation. | ||||
* `0` means : a frame has just been fully decoded and flushed. | ||||
*/ | ||||
ZSTDLIB_API size_t ZSTD_decompress_generic(ZSTD_DCtx* dctx, | ||||
ZSTD_outBuffer* output, | ||||
ZSTD_inBuffer* input); | ||||
/*! ZSTD_decompress_generic_simpleArgs() : | ||||
* Same as ZSTD_decompress_generic(), | ||||
* but using only integral types as arguments. | ||||
* Argument list is larger than ZSTD_{in,out}Buffer, | ||||
* but can be helpful for binders from dynamic languages | ||||
* which have troubles handling structures containing memory pointers. | ||||
*/ | ||||
ZSTDLIB_API size_t ZSTD_decompress_generic_simpleArgs ( | ||||
ZSTD_DCtx* dctx, | ||||
void* dst, size_t dstCapacity, size_t* dstPos, | ||||
const void* src, size_t srcSize, size_t* srcPos); | ||||
/*! ZSTD_DCtx_reset() : | ||||
* Return a DCtx to clean state. | ||||
* If a decompression was ongoing, any internal data not yet flushed is cancelled. | ||||
* All parameters are back to default values, including sticky ones. | ||||
* Dictionary (if any) is dropped. | ||||
* Parameters can be modified again after a reset. | ||||
*/ | ||||
ZSTDLIB_API void ZSTD_DCtx_reset(ZSTD_DCtx* dctx); | ||||
/* ============================ */ | ||||
/** Block level API */ | ||||
/* ============================ */ | ||||
/*! | ||||
|
r30434 | 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 | ||||
|
r37513 | + 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_getBlockSize() <= ZSTD_BLOCKSIZE_MAX == 128 KB | ||||
+ 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. | ||||
|
r30434 | - 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 !!! | ||||
|
r37513 | + In case of multiple successive blocks, should some of them be uncompressed, | ||
decoder must be informed of their existence in order to follow proper history. | ||||
Use ZSTD_insertBlock() for such a case. | ||||
|
r30434 | */ | ||
/*===== Raw zstd block functions =====*/ | ||||
|
r37513 | ZSTDLIB_API size_t ZSTD_getBlockSize (const ZSTD_CCtx* cctx); | ||
|
r30434 | 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); | ||||
|
r37513 | ZSTDLIB_API size_t ZSTD_insertBlock (ZSTD_DCtx* dctx, const void* blockStart, size_t blockSize); /**< insert uncompressed block into `dctx` history. Useful for multi-blocks decompression. */ | ||
|
r30434 | |||
|
r30822 | #endif /* ZSTD_H_ZSTD_STATIC_LINKING_ONLY */ | ||
|
r30434 | |||
#if defined (__cplusplus) | ||||
} | ||||
#endif | ||||