440 lines
21 KiB
C
440 lines
21 KiB
C
/*
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zstd - standard compression library
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Header File
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Copyright (C) 2014-2016, Yann Collet.
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BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are
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met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above
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copyright notice, this list of conditions and the following disclaimer
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in the documentation and/or other materials provided with the
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distribution.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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You can contact the author at :
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- zstd source repository : https://github.com/Cyan4973/zstd
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*/
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#ifndef ZSTD_H_235446
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#define ZSTD_H_235446
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#if defined (__cplusplus)
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extern "C" {
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#endif
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/*-*************************************
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* Dependencies
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***************************************/
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#include <stddef.h> /* size_t */
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/*-***************************************************************
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* Export parameters
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*****************************************************************/
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/*!
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* ZSTD_DLL_EXPORT :
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* Enable exporting of functions when building a Windows DLL
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*/
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#if defined(_WIN32) && defined(ZSTD_DLL_EXPORT) && (ZSTD_DLL_EXPORT==1)
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# define ZSTDLIB_API __declspec(dllexport)
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#else
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# define ZSTDLIB_API
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#endif
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/* *************************************
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* Version
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***************************************/
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#define ZSTD_VERSION_MAJOR 0
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#define ZSTD_VERSION_MINOR 7
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#define ZSTD_VERSION_RELEASE 1
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#define ZSTD_LIB_VERSION ZSTD_VERSION_MAJOR.ZSTD_VERSION_MINOR.ZSTD_VERSION_RELEASE
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#define ZSTD_QUOTE(str) #str
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#define ZSTD_EXPAND_AND_QUOTE(str) ZSTD_QUOTE(str)
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#define ZSTD_VERSION_STRING ZSTD_EXPAND_AND_QUOTE(ZSTD_LIB_VERSION)
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#define ZSTD_VERSION_NUMBER (ZSTD_VERSION_MAJOR *100*100 + ZSTD_VERSION_MINOR *100 + ZSTD_VERSION_RELEASE)
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ZSTDLIB_API unsigned ZSTD_versionNumber (void);
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/* *************************************
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* Simple functions
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***************************************/
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/*! ZSTD_compress() :
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Compresses `srcSize` bytes from buffer `src` into buffer `dst` of size `dstCapacity`.
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Destination buffer must be already allocated.
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Compression runs faster if `dstCapacity` >= `ZSTD_compressBound(srcSize)`.
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@return : the number of bytes written into `dst`,
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or an error code if it fails (which can be tested using ZSTD_isError()) */
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ZSTDLIB_API size_t ZSTD_compress( void* dst, size_t dstCapacity,
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const void* src, size_t srcSize,
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int compressionLevel);
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/*! ZSTD_decompress() :
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`compressedSize` : is the _exact_ size of the compressed blob, otherwise decompression will fail.
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`dstCapacity` must be large enough, equal or larger than originalSize.
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@return : the number of bytes decompressed into `dst` (<= `dstCapacity`),
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or an errorCode if it fails (which can be tested using ZSTD_isError()) */
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ZSTDLIB_API size_t ZSTD_decompress( void* dst, size_t dstCapacity,
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const void* src, size_t compressedSize);
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/* *************************************
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* Helper functions
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***************************************/
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ZSTDLIB_API size_t ZSTD_compressBound(size_t srcSize); /*!< maximum compressed size (worst case scenario) */
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/* Error Management */
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ZSTDLIB_API unsigned ZSTD_isError(size_t code); /*!< tells if a `size_t` function result is an error code */
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ZSTDLIB_API const char* ZSTD_getErrorName(size_t code); /*!< provides readable string for an error code */
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/* *************************************
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* Explicit memory management
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***************************************/
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/** Compression context */
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typedef struct ZSTD_CCtx_s ZSTD_CCtx; /*< incomplete type */
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ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx(void);
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ZSTDLIB_API size_t ZSTD_freeCCtx(ZSTD_CCtx* cctx); /*!< @return : errorCode */
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/** ZSTD_compressCCtx() :
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Same as ZSTD_compress(), but requires an already allocated ZSTD_CCtx (see ZSTD_createCCtx()) */
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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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/** Decompression context */
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typedef struct ZSTD_DCtx_s ZSTD_DCtx;
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ZSTDLIB_API ZSTD_DCtx* ZSTD_createDCtx(void);
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ZSTDLIB_API size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx); /*!< @return : errorCode */
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/** ZSTD_decompressDCtx() :
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* Same as ZSTD_decompress(), but requires an already allocated ZSTD_DCtx (see ZSTD_createDCtx()) */
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ZSTDLIB_API size_t ZSTD_decompressDCtx(ZSTD_DCtx* ctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
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/*-************************
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* Simple dictionary API
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***************************/
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/*! ZSTD_compress_usingDict() :
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* Compression using a pre-defined Dictionary content (see dictBuilder).
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* Note 1 : This function load the dictionary, resulting in a significant startup time.
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* Note 2 : `dict` must remain valid and unmodified during compression operation.
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* Note 3 : `dict` can be `NULL`, in which case, it's equivalent to ZSTD_compressCCtx() */
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ZSTDLIB_API size_t ZSTD_compress_usingDict(ZSTD_CCtx* ctx,
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void* dst, size_t dstCapacity,
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const void* src, size_t srcSize,
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const void* dict,size_t dictSize,
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int compressionLevel);
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/*! ZSTD_decompress_usingDict() :
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* Decompression using a pre-defined Dictionary content (see dictBuilder).
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* Dictionary must be identical to the one used during compression.
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* Note 1 : This function load the dictionary, resulting in a significant startup time
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* Note 2 : `dict` must remain valid and unmodified during compression operation.
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* Note 3 : `dict` can be `NULL`, in which case, it's equivalent to ZSTD_decompressDCtx() */
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ZSTDLIB_API size_t ZSTD_decompress_usingDict(ZSTD_DCtx* dctx,
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void* dst, size_t dstCapacity,
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const void* src, size_t srcSize,
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const void* dict,size_t dictSize);
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/*-**************************
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* Advanced Dictionary API
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****************************/
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/*! ZSTD_createCDict() :
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* Create a digested dictionary, ready to start compression operation without startup delay.
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* `dict` can be released after creation */
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typedef struct ZSTD_CDict_s ZSTD_CDict;
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ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict(const void* dict, size_t dictSize, int compressionLevel);
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ZSTDLIB_API size_t ZSTD_freeCDict(ZSTD_CDict* CDict);
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/*! ZSTD_compress_usingCDict() :
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* Compression using a pre-digested Dictionary.
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* Much faster than ZSTD_compress_usingDict() when same dictionary is used multiple times.
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* Note that compression level is decided during dictionary creation */
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ZSTDLIB_API size_t ZSTD_compress_usingCDict(ZSTD_CCtx* cctx,
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void* dst, size_t dstCapacity,
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const void* src, size_t srcSize,
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const ZSTD_CDict* cdict);
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/*! ZSTD_createDDict() :
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* Create a digested dictionary, ready to start decompression operation without startup delay.
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* `dict` can be released after creation */
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typedef struct ZSTD_DDict_s ZSTD_DDict;
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ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict(const void* dict, size_t dictSize);
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ZSTDLIB_API size_t ZSTD_freeDDict(ZSTD_DDict* ddict);
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/*! ZSTD_decompress_usingDDict() :
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* Decompression using a pre-digested Dictionary
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* Much faster than ZSTD_decompress_usingDict() when same dictionary is used multiple times. */
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ZSTDLIB_API size_t ZSTD_decompress_usingDDict(ZSTD_DCtx* dctx,
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void* dst, size_t dstCapacity,
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const void* src, size_t srcSize,
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const ZSTD_DDict* ddict);
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#ifdef ZSTD_STATIC_LINKING_ONLY
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/* ====================================================================================
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* The definitions in this section are considered experimental.
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* They should never be used in association with a dynamic library, as they may change in the future.
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* They are provided for advanced usages.
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* Use them only in association with static linking.
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* ==================================================================================== */
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/*--- Dependency ---*/
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#include "mem.h" /* U32 */
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/*--- Constants ---*/
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#define ZSTD_MAGICNUMBER 0xFD2FB527 /* v0.7 */
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#define ZSTD_MAGIC_SKIPPABLE_START 0x184D2A50U
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#define ZSTD_WINDOWLOG_MAX ((U32)(MEM_32bits() ? 25 : 27))
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#define ZSTD_WINDOWLOG_MIN 18
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#define ZSTD_CHAINLOG_MAX (ZSTD_WINDOWLOG_MAX+1)
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#define ZSTD_CHAINLOG_MIN 4
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#define ZSTD_HASHLOG_MAX ZSTD_WINDOWLOG_MAX
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#define ZSTD_HASHLOG_MIN 12
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#define ZSTD_HASHLOG3_MAX 17
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#define ZSTD_HASHLOG3_MIN 15
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#define ZSTD_SEARCHLOG_MAX (ZSTD_WINDOWLOG_MAX-1)
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#define ZSTD_SEARCHLOG_MIN 1
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#define ZSTD_SEARCHLENGTH_MAX 7
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#define ZSTD_SEARCHLENGTH_MIN 3
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#define ZSTD_TARGETLENGTH_MIN 4
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#define ZSTD_TARGETLENGTH_MAX 999
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#define ZSTD_FRAMEHEADERSIZE_MAX 18 /* for static allocation */
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static const size_t ZSTD_frameHeaderSize_min = 5;
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static const size_t ZSTD_frameHeaderSize_max = ZSTD_FRAMEHEADERSIZE_MAX;
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static const size_t ZSTD_skippableHeaderSize = 8; /* magic number + skippable frame length */
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/*--- Types ---*/
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typedef enum { ZSTD_fast, ZSTD_greedy, ZSTD_lazy, ZSTD_lazy2, ZSTD_btlazy2, ZSTD_btopt } ZSTD_strategy; /*< from faster to stronger */
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typedef struct {
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U32 windowLog; /*< largest match distance : larger == more compression, more memory needed during decompression */
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U32 chainLog; /*< fully searched segment : larger == more compression, slower, more memory (useless for fast) */
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U32 hashLog; /*< dispatch table : larger == faster, more memory */
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U32 searchLog; /*< nb of searches : larger == more compression, slower */
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U32 searchLength; /*< match length searched : larger == faster decompression, sometimes less compression */
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U32 targetLength; /*< acceptable match size for optimal parser (only) : larger == more compression, slower */
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ZSTD_strategy strategy;
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} ZSTD_compressionParameters;
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typedef struct {
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U32 contentSizeFlag; /*< 1: content size will be in frame header (if known). */
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U32 checksumFlag; /*< 1: will generate a 22-bits checksum at end of frame, to be used for error detection by decompressor */
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U32 noDictIDFlag; /*< 1: no dict ID will be saved into frame header (if dictionary compression) */
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} ZSTD_frameParameters;
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typedef struct {
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ZSTD_compressionParameters cParams;
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ZSTD_frameParameters fParams;
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} ZSTD_parameters;
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/* custom memory allocation functions */
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typedef void* (*ZSTD_allocFunction) (void* opaque, size_t size);
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typedef void (*ZSTD_freeFunction) (void* opaque, void* address);
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typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; void* opaque; } ZSTD_customMem;
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/*-*************************************
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* Advanced compression functions
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***************************************/
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/*! ZSTD_createCCtx_advanced() :
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* Create a ZSTD compression context using external alloc and free functions */
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ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem);
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/*! ZSTD_createCDict_advanced() :
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* Create a ZSTD_CDict using external alloc and free, and customized compression parameters */
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ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_advanced(const void* dict, size_t dictSize,
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ZSTD_parameters params, ZSTD_customMem customMem);
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ZSTDLIB_API unsigned ZSTD_maxCLevel (void);
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/*! ZSTD_getCParams() :
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* @return ZSTD_compressionParameters structure for a selected compression level and srcSize.
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* `srcSize` value is optional, select 0 if not known */
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ZSTDLIB_API ZSTD_compressionParameters ZSTD_getCParams(int compressionLevel, U64 srcSize, size_t dictSize);
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/*! ZSTD_checkParams() :
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* Ensure param values remain within authorized range */
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ZSTDLIB_API size_t ZSTD_checkCParams(ZSTD_compressionParameters params);
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/*! ZSTD_adjustParams() :
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* optimize params for a given `srcSize` and `dictSize`.
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* both values are optional, select `0` if unknown. */
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ZSTDLIB_API ZSTD_compressionParameters ZSTD_adjustCParams(ZSTD_compressionParameters cPar, U64 srcSize, size_t dictSize);
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/*! ZSTD_compress_advanced() :
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* Same as ZSTD_compress_usingDict(), with fine-tune control of each compression parameter */
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ZSTDLIB_API size_t ZSTD_compress_advanced (ZSTD_CCtx* ctx,
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void* dst, size_t dstCapacity,
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const void* src, size_t srcSize,
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const void* dict,size_t dictSize,
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ZSTD_parameters params);
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/*--- Advanced Decompression functions ---*/
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/*! ZSTD_createDCtx_advanced() :
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* Create a ZSTD decompression context using external alloc and free functions */
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ZSTDLIB_API ZSTD_DCtx* ZSTD_createDCtx_advanced(ZSTD_customMem customMem);
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/* ****************************************************************
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* Streaming functions (direct mode - synchronous and buffer-less)
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******************************************************************/
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ZSTDLIB_API size_t ZSTD_compressBegin(ZSTD_CCtx* cctx, int compressionLevel);
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ZSTDLIB_API size_t ZSTD_compressBegin_usingDict(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, int compressionLevel);
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ZSTDLIB_API size_t ZSTD_compressBegin_advanced(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, ZSTD_parameters params, U64 pledgedSrcSize);
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ZSTDLIB_API size_t ZSTD_copyCCtx(ZSTD_CCtx* cctx, const ZSTD_CCtx* preparedCCtx);
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ZSTDLIB_API size_t ZSTD_compressContinue(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
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ZSTDLIB_API size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity);
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/*
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A ZSTD_CCtx object is required to track streaming operations.
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Use ZSTD_createCCtx() / ZSTD_freeCCtx() to manage resource.
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ZSTD_CCtx object can be re-used multiple times within successive compression operations.
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Start by initializing a context.
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Use ZSTD_compressBegin(), or ZSTD_compressBegin_usingDict() for dictionary compression,
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or ZSTD_compressBegin_advanced(), for finer parameter control.
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It's also possible to duplicate a reference context which has already been initialized, using ZSTD_copyCCtx()
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Then, consume your input using ZSTD_compressContinue().
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ZSTD_compressContinue() presumes prior data is still accessible and unmodified (up to maximum distance size, see WindowLog).
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The interface is synchronous, so input will be entirely consumed and produce associated compressed output.
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You must ensure there is enough space in destination buffer to store compressed data under worst case scenario.
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Worst case evaluation is provided by ZSTD_compressBound().
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Finish a frame with ZSTD_compressEnd(), which will write the epilogue.
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Without epilogue, frames will be considered unfinished (broken) by decoders.
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You can then reuse ZSTD_CCtx to compress some new frame.
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*/
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typedef struct {
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U64 frameContentSize;
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U32 windowSize;
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U32 dictID;
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U32 checksumFlag;
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} ZSTD_frameParams;
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ZSTDLIB_API size_t ZSTD_getFrameParams(ZSTD_frameParams* fparamsPtr, const void* src, size_t srcSize); /**< doesn't consume input */
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ZSTDLIB_API size_t ZSTD_decompressBegin(ZSTD_DCtx* dctx);
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ZSTDLIB_API size_t ZSTD_decompressBegin_usingDict(ZSTD_DCtx* dctx, const void* dict, size_t dictSize);
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ZSTDLIB_API void ZSTD_copyDCtx(ZSTD_DCtx* dctx, const ZSTD_DCtx* preparedDCtx);
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ZSTDLIB_API size_t ZSTD_nextSrcSizeToDecompress(ZSTD_DCtx* dctx);
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ZSTDLIB_API size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
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/*
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Streaming decompression, direct mode (bufferless)
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A ZSTD_DCtx object is required to track streaming operations.
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Use ZSTD_createDCtx() / ZSTD_freeDCtx() to manage it.
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A ZSTD_DCtx object can be re-used multiple times.
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First optional operation is to retrieve frame parameters, using ZSTD_getFrameParams(), which doesn't consume the input.
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It can provide the minimum size of rolling buffer required to properly decompress data,
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and optionally the final size of uncompressed content.
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(Note : content size is an optional info that may not be present. 0 means : content size unknown)
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Frame parameters are extracted from the beginning of compressed frame.
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The amount of data to read is variable, from ZSTD_frameHeaderSize_min to ZSTD_frameHeaderSize_max (so if `srcSize` >= ZSTD_frameHeaderSize_max, it will always work)
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If `srcSize` is too small for operation to succeed, function will return the minimum size it requires to produce a result.
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Result : 0 when successful, it means the ZSTD_frameParams structure has been filled.
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>0 : means there is not enough data into `src`. Provides the expected size to successfully decode header.
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errorCode, which can be tested using ZSTD_isError()
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Start decompression, with ZSTD_decompressBegin() or ZSTD_decompressBegin_usingDict().
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Alternatively, you can copy a prepared context, using ZSTD_copyDCtx().
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Then use ZSTD_nextSrcSizeToDecompress() and ZSTD_decompressContinue() alternatively.
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ZSTD_nextSrcSizeToDecompress() tells how much bytes to provide as 'srcSize' to ZSTD_decompressContinue().
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ZSTD_decompressContinue() requires this exact amount of bytes, or it will fail.
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ZSTD_decompressContinue() needs previous data blocks during decompression, up to (1 << windowlog).
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They should preferably be located contiguously, prior to current block. Alternatively, a round buffer is also possible.
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@result of ZSTD_decompressContinue() is the number of bytes regenerated within 'dst' (necessarily <= dstCapacity).
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It can be zero, which is not an error; it just means ZSTD_decompressContinue() has decoded some header.
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A frame is fully decoded when ZSTD_nextSrcSizeToDecompress() returns zero.
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Context can then be reset to start a new decompression.
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Skippable frames allow the integration of user-defined data into a flow of concatenated frames.
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Skippable frames will be ignored (skipped) by a decompressor. The format of skippable frame is following:
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a) Skippable frame ID - 4 Bytes, Little endian format, any value from 0x184D2A50 to 0x184D2A5F
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b) Frame Size - 4 Bytes, Little endian format, unsigned 32-bits
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c) Frame Content - any content (User Data) of length equal to Frame Size
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For skippable frames ZSTD_decompressContinue() always returns 0.
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For skippable frames ZSTD_getFrameParams() returns fparamsPtr->windowLog==0 what means that a frame is skippable.
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It also returns Frame Size as fparamsPtr->frameContentSize.
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*/
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/* **************************************
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* Block functions
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****************************************/
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/*! Block functions produce and decode raw zstd blocks, without frame metadata.
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User will have to take in charge required information to regenerate data, such as compressed and content sizes.
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A few rules to respect :
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- Uncompressed block size must be <= ZSTD_BLOCKSIZE_MAX (128 KB)
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- Compressing or decompressing requires a context structure
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+ Use ZSTD_createCCtx() and ZSTD_createDCtx()
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- It is necessary to init context before starting
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+ compression : ZSTD_compressBegin()
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+ decompression : ZSTD_decompressBegin()
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+ variants _usingDict() are also allowed
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+ copyCCtx() and copyDCtx() work too
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- When a block is considered not compressible enough, ZSTD_compressBlock() result will be zero.
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In which case, nothing is produced into `dst`.
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+ User must test for such outcome and deal directly with uncompressed data
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+ ZSTD_decompressBlock() doesn't accept uncompressed data as input !!
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*/
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#define ZSTD_BLOCKSIZE_MAX (128 * 1024) /* define, for static allocation */
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ZSTDLIB_API size_t ZSTD_compressBlock (ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
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ZSTDLIB_API size_t ZSTD_decompressBlock(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
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/*-*************************************
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|
* Error management
|
|
***************************************/
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|
#include "error_public.h"
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|
/*! ZSTD_getErrorCode() :
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|
convert a `size_t` function result into a `ZSTD_ErrorCode` enum type,
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|
which can be used to compare directly with enum list published into "error_public.h" */
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ZSTDLIB_API ZSTD_ErrorCode ZSTD_getErrorCode(size_t functionResult);
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ZSTDLIB_API const char* ZSTD_getErrorString(ZSTD_ErrorCode code);
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#endif /* ZSTD_STATIC_LINKING_ONLY */
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|
|
|
#if defined (__cplusplus)
|
|
}
|
|
#endif
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|
|
|
#endif /* ZSTD_H_235446 */
|