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# ifndef LZ4_H_2983827168210
# define LZ4_H_2983827168210
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/*
* LZ4 - Fast LZ compression algorithm
* Header File
* Copyright ( C ) 2011 - present , Yann Collet .
BSD 2 - Clause License ( http : //www.opensource.org/licenses/bsd-license.php)
Redistribution and use in source and binary forms , with or without
modification , are permitted provided that the following conditions are
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
in the documentation and / or other materials provided with the
distribution .
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
" AS IS " AND ANY EXPRESS OR IMPLIED WARRANTIES , INCLUDING , BUT NOT
LIMITED TO , THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED . IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT , INDIRECT , INCIDENTAL ,
SPECIAL , EXEMPLARY , OR CONSEQUENTIAL DAMAGES ( INCLUDING , BUT NOT
LIMITED TO , PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES ; LOSS OF USE ,
DATA , OR PROFITS ; OR BUSINESS INTERRUPTION ) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY , WHETHER IN CONTRACT , STRICT LIABILITY , OR TORT
( INCLUDING NEGLIGENCE OR OTHERWISE ) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE , EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE .
You can contact the author at :
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- LZ4 homepage : http : //www.lz4.org
- LZ4 source repository : https : //github.com/lz4/lz4
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*/
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# if defined(__cplusplus)
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extern " C " {
# endif
/* --- Dependency --- */
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# include <stddef.h> /* size_t */
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/**
Introduction
LZ4 is lossless compression algorithm , providing compression speed > 500 MB / s per core ,
scalable with multi - cores CPU . It features an extremely fast decoder , with speed in
multiple GB / s per core , typically reaching RAM speed limits on multi - core systems .
The LZ4 compression library provides in - memory compression and decompression functions .
It gives full buffer control to user .
Compression can be done in :
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- a single step ( described as Simple Functions )
- a single step , reusing a context ( described in Advanced Functions )
- unbounded multiple steps ( described as Streaming compression )
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lz4 . h generates and decodes LZ4 - compressed blocks ( doc / lz4_Block_format . md ) .
Decompressing such a compressed block requires additional metadata .
Exact metadata depends on exact decompression function .
For the typical case of LZ4_decompress_safe ( ) ,
metadata includes block ' s compressed size , and maximum bound of decompressed size .
Each application is free to encode and pass such metadata in whichever way it wants .
lz4 . h only handle blocks , it can not generate Frames .
Blocks are different from Frames ( doc / lz4_Frame_format . md ) .
Frames bundle both blocks and metadata in a specified manner .
Embedding metadata is required for compressed data to be self - contained and portable .
Frame format is delivered through a companion API , declared in lz4frame . h .
The ` lz4 ` CLI can only manage frames .
*/
/*^***************************************************************
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* Export parameters
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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/*
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* LZ4_DLL_EXPORT :
* Enable exporting of functions when building a Windows DLL
* LZ4LIB_VISIBILITY :
* Control library symbols visibility .
*/
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# ifndef LZ4LIB_VISIBILITY
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# if defined(__GNUC__) && (__GNUC__ >= 4)
# define LZ4LIB_VISIBILITY __attribute__((visibility("default")))
# else
# define LZ4LIB_VISIBILITY
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# endif
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# endif
# if defined(LZ4_DLL_EXPORT) && (LZ4_DLL_EXPORT == 1)
# define LZ4LIB_API __declspec(dllexport) LZ4LIB_VISIBILITY
# elif defined(LZ4_DLL_IMPORT) && (LZ4_DLL_IMPORT == 1)
# define LZ4LIB_API __declspec(dllimport) LZ4LIB_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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# else
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# define LZ4LIB_API LZ4LIB_VISIBILITY
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# endif
/*------ Version ------*/
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# define LZ4_VERSION_MAJOR 1 /* for breaking interface changes */
# define LZ4_VERSION_MINOR 9 /* for new (non-breaking) interface capabilities */
# define LZ4_VERSION_RELEASE 2 /* for tweaks, bug-fixes, or development */
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# define LZ4_VERSION_NUMBER (LZ4_VERSION_MAJOR * 100 * 100 + LZ4_VERSION_MINOR * 100 + LZ4_VERSION_RELEASE)
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# define LZ4_LIB_VERSION LZ4_VERSION_MAJOR.LZ4_VERSION_MINOR.LZ4_VERSION_RELEASE
# define LZ4_QUOTE(str) #str
# define LZ4_EXPAND_AND_QUOTE(str) LZ4_QUOTE(str)
# define LZ4_VERSION_STRING LZ4_EXPAND_AND_QUOTE(LZ4_LIB_VERSION)
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LZ4LIB_API int LZ4_versionNumber ( void ) ; /**< library version number; useful to check dll version */
LZ4LIB_API const char * LZ4_versionString ( void ) ; /**< library version string; useful to check dll version */
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/*-************************************
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* Tuning parameter
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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/*!
* LZ4_MEMORY_USAGE :
* Memory usage formula : N - > 2 ^ N Bytes ( examples : 10 - > 1 KB ; 12 - > 4 KB ; 16 - > 64 KB ; 20 - > 1 MB ; etc . )
* Increasing memory usage improves compression ratio .
* Reduced memory usage may improve speed , thanks to better cache locality .
* Default value is 14 , for 16 KB , which nicely fits into Intel x86 L1 cache
*/
# ifndef LZ4_MEMORY_USAGE
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# define LZ4_MEMORY_USAGE 14
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# endif
/*-************************************
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* Simple Functions
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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/*! LZ4_compress_default() :
* Compresses ' srcSize ' bytes from buffer ' src '
* into already allocated ' dst ' buffer of size ' dstCapacity ' .
* Compression is guaranteed to succeed if ' dstCapacity ' > = LZ4_compressBound ( srcSize ) .
* It also runs faster , so it ' s a recommended setting .
* If the function cannot compress ' src ' into a more limited ' dst ' budget ,
* compression stops * immediately * , and the function result is zero .
* In which case , ' dst ' content is undefined ( invalid ) .
* srcSize : max supported value is LZ4_MAX_INPUT_SIZE .
* dstCapacity : size of buffer ' dst ' ( which must be already allocated )
* @ return : the number of bytes written into buffer ' dst ' ( necessarily < = dstCapacity )
* or 0 if compression fails
* Note : This function is protected against buffer overflow scenarios ( never writes outside ' dst ' buffer , nor read outside ' source ' buffer ) .
*/
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LZ4LIB_API int LZ4_compress_default ( const char * src , char * dst , int srcSize , int dstCapacity ) ;
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/*! LZ4_decompress_safe() :
* compressedSize : is the exact complete size of the compressed block .
* dstCapacity : is the size of destination buffer ( which must be already allocated ) , presumed an upper bound of decompressed size .
* @ return : the number of bytes decompressed into destination buffer ( necessarily < = dstCapacity )
* If destination buffer is not large enough , decoding will stop and output an error code ( negative value ) .
* If the source stream is detected malformed , the function will stop decoding and return a negative result .
* Note 1 : This function is protected against malicious data packets :
* it will never writes outside ' dst ' buffer , nor read outside ' source ' buffer ,
* even if the compressed block is maliciously modified to order the decoder to do these actions .
* In such case , the decoder stops immediately , and considers the compressed block malformed .
* Note 2 : compressedSize and dstCapacity must be provided to the function , the compressed block does not contain them .
* The implementation is free to send / store / derive this information in whichever way is most beneficial .
* If there is a need for a different format which bundles together both compressed data and its metadata , consider looking at lz4frame . h instead .
*/
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LZ4LIB_API int LZ4_decompress_safe ( const char * src , char * dst , int compressedSize , int dstCapacity ) ;
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/*-************************************
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* Advanced Functions
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
# define LZ4_MAX_INPUT_SIZE 0x7E000000 /* 2 113 929 216 bytes */
# define LZ4_COMPRESSBOUND(isize) ((unsigned)(isize) > (unsigned)LZ4_MAX_INPUT_SIZE ? 0 : (isize) + ((isize) / 255) + 16)
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/*! LZ4_compressBound() :
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Provides the maximum size that LZ4 compression may output in a " worst case " scenario ( input data not compressible )
This function is primarily useful for memory allocation purposes ( destination buffer size ) .
Macro LZ4_COMPRESSBOUND ( ) is also provided for compilation - time evaluation ( stack memory allocation for example ) .
Note that LZ4_compress_default ( ) compresses faster when dstCapacity is > = LZ4_compressBound ( srcSize )
inputSize : max supported value is LZ4_MAX_INPUT_SIZE
return : maximum output size in a " worst case " scenario
or 0 , if input size is incorrect ( too large or negative )
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*/
LZ4LIB_API int LZ4_compressBound ( int inputSize ) ;
/*! LZ4_compress_fast() :
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Same as LZ4_compress_default ( ) , but allows selection of " acceleration " factor .
The larger the acceleration value , the faster the algorithm , but also the lesser the compression .
It ' s a trade - off . It can be fine tuned , with each successive value providing roughly + ~ 3 % to speed .
An acceleration value of " 1 " is the same as regular LZ4_compress_default ( )
Values < = 0 will be replaced by ACCELERATION_DEFAULT ( currently = = 1 , see lz4 . c ) .
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*/
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LZ4LIB_API int LZ4_compress_fast ( const char * src , char * dst , int srcSize , int dstCapacity , int acceleration ) ;
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/*! LZ4_compress_fast_extState() :
* Same as LZ4_compress_fast ( ) , using an externally allocated memory space for its state .
* Use LZ4_sizeofState ( ) to know how much memory must be allocated ,
* and allocate it on 8 - bytes boundaries ( using ` malloc ( ) ` typically ) .
* Then , provide this buffer as ` void * state ` to compression function .
*/
LZ4LIB_API int LZ4_sizeofState ( void ) ;
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LZ4LIB_API int LZ4_compress_fast_extState ( void * state , const char * src , char * dst , int srcSize , int dstCapacity , int acceleration ) ;
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/*! LZ4_compress_destSize() :
* Reverse the logic : compresses as much data as possible from ' src ' buffer
* into already allocated buffer ' dst ' , of size > = ' targetDestSize ' .
* This function either compresses the entire ' src ' content into ' dst ' if it ' s large enough ,
* or fill ' dst ' buffer completely with as much data as possible from ' src ' .
* note : acceleration parameter is fixed to " default " .
*
* * srcSizePtr : will be modified to indicate how many bytes where read from ' src ' to fill ' dst ' .
* New value is necessarily < = input value .
* @ return : Nb bytes written into ' dst ' ( necessarily < = targetDestSize )
* or 0 if compression fails .
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*/
LZ4LIB_API int LZ4_compress_destSize ( const char * src , char * dst , int * srcSizePtr , int targetDstSize ) ;
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/*! LZ4_decompress_safe_partial() :
* Decompress an LZ4 compressed block , of size ' srcSize ' at position ' src ' ,
* into destination buffer ' dst ' of size ' dstCapacity ' .
* Up to ' targetOutputSize ' bytes will be decoded .
* The function stops decoding on reaching this objective ,
* which can boost performance when only the beginning of a block is required .
*
* @ return : the number of bytes decoded in ` dst ` ( necessarily < = dstCapacity )
* If source stream is detected malformed , function returns a negative result .
*
* Note : @ return can be < targetOutputSize , if compressed block contains less data .
*
* Note 2 : this function features 2 parameters , targetOutputSize and dstCapacity ,
* and expects targetOutputSize < = dstCapacity .
* It effectively stops decoding on reaching targetOutputSize ,
* so dstCapacity is kind of redundant .
* This is because in a previous version of this function ,
* decoding operation would not " break " a sequence in the middle .
* As a consequence , there was no guarantee that decoding would stop at exactly targetOutputSize ,
* it could write more bytes , though only up to dstCapacity .
* Some " margin " used to be required for this operation to work properly .
* This is no longer necessary .
* The function nonetheless keeps its signature , in an effort to not break API .
*/
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LZ4LIB_API int LZ4_decompress_safe_partial ( const char * src , char * dst , int srcSize , int targetOutputSize , int dstCapacity ) ;
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/*-*********************************************
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* Streaming Compression Functions
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
typedef union LZ4_stream_u LZ4_stream_t ; /* incomplete type (defined later) */
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LZ4LIB_API LZ4_stream_t * LZ4_createStream ( void ) ;
LZ4LIB_API int LZ4_freeStream ( LZ4_stream_t * streamPtr ) ;
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/*! LZ4_resetStream_fast() : v1.9.0+
* Use this to prepare an LZ4_stream_t for a new chain of dependent blocks
* ( e . g . , LZ4_compress_fast_continue ( ) ) .
*
* An LZ4_stream_t must be initialized once before usage .
* This is automatically done when created by LZ4_createStream ( ) .
* However , should the LZ4_stream_t be simply declared on stack ( for example ) ,
* it ' s necessary to initialize it first , using LZ4_initStream ( ) .
*
* After init , start any new stream with LZ4_resetStream_fast ( ) .
* A same LZ4_stream_t can be re - used multiple times consecutively
* and compress multiple streams ,
* provided that it starts each new stream with LZ4_resetStream_fast ( ) .
*
* LZ4_resetStream_fast ( ) is much faster than LZ4_initStream ( ) ,
* but is not compatible with memory regions containing garbage data .
*
* Note : it ' s only useful to call LZ4_resetStream_fast ( )
* in the context of streaming compression .
* The * extState * functions perform their own resets .
* Invoking LZ4_resetStream_fast ( ) before is redundant , and even counterproductive .
*/
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LZ4LIB_API void LZ4_resetStream_fast ( LZ4_stream_t * streamPtr ) ;
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/*! LZ4_loadDict() :
* Use this function to reference a static dictionary into LZ4_stream_t .
* The dictionary must remain available during compression .
* LZ4_loadDict ( ) triggers a reset , so any previous data will be forgotten .
* The same dictionary will have to be loaded on decompression side for successful decoding .
* Dictionary are useful for better compression of small data ( KB range ) .
* While LZ4 accept any input as dictionary ,
* results are generally better when using Zstandard ' s Dictionary Builder .
* Loading a size of 0 is allowed , and is the same as reset .
* @ return : loaded dictionary size , in bytes ( necessarily < = 64 KB )
*/
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LZ4LIB_API int LZ4_loadDict ( LZ4_stream_t * streamPtr , const char * dictionary , int dictSize ) ;
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/*! LZ4_compress_fast_continue() :
* Compress ' src ' content using data from previously compressed blocks , for better compression ratio .
* ' dst ' buffer must be already allocated .
* If dstCapacity > = LZ4_compressBound ( srcSize ) , compression is guaranteed to succeed , and runs faster .
*
* @ return : size of compressed block
* or 0 if there is an error ( typically , cannot fit into ' dst ' ) .
*
* Note 1 : Each invocation to LZ4_compress_fast_continue ( ) generates a new block .
* Each block has precise boundaries .
* Each block must be decompressed separately , calling LZ4_decompress_ * ( ) with relevant metadata .
* It ' s not possible to append blocks together and expect a single invocation of LZ4_decompress_ * ( ) to decompress them together .
*
* Note 2 : The previous 64 KB of source data is __assumed__ to remain present , unmodified , at same address in memory !
*
* Note 3 : When input is structured as a double - buffer , each buffer can have any size , including < 64 KB .
* Make sure that buffers are separated , by at least one byte .
* This construction ensures that each block only depends on previous block .
*
* Note 4 : If input buffer is a ring - buffer , it can have any size , including < 64 KB .
*
* Note 5 : After an error , the stream status is undefined ( invalid ) , it can only be reset or freed .
*/
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LZ4LIB_API int LZ4_compress_fast_continue ( LZ4_stream_t * streamPtr , const char * src , char * dst , int srcSize , int dstCapacity , int acceleration ) ;
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/*! LZ4_saveDict() :
* If last 64 KB data cannot be guaranteed to remain available at its current memory location ,
* save it into a safer place ( char * safeBuffer ) .
* This is schematically equivalent to a memcpy ( ) followed by LZ4_loadDict ( ) ,
* but is much faster , because LZ4_saveDict ( ) doesn ' t need to rebuild tables .
* @ return : saved dictionary size in bytes ( necessarily < = maxDictSize ) , or 0 if error .
*/
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LZ4LIB_API int LZ4_saveDict ( LZ4_stream_t * streamPtr , char * safeBuffer , int maxDictSize ) ;
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/*-**********************************************
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* Streaming Decompression Functions
* Bufferless synchronous API
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
typedef union LZ4_streamDecode_u LZ4_streamDecode_t ; /* tracking context */
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/*! LZ4_createStreamDecode() and LZ4_freeStreamDecode() :
* creation / destruction of streaming decompression tracking context .
* A tracking context can be re - used multiple times .
*/
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LZ4LIB_API LZ4_streamDecode_t * LZ4_createStreamDecode ( void ) ;
LZ4LIB_API int LZ4_freeStreamDecode ( LZ4_streamDecode_t * LZ4_stream ) ;
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/*! LZ4_setStreamDecode() :
* An LZ4_streamDecode_t context can be allocated once and re - used multiple times .
* Use this function to start decompression of a new stream of blocks .
* A dictionary can optionally be set . Use NULL or size 0 for a reset order .
* Dictionary is presumed stable : it must remain accessible and unmodified during next decompression .
* @ return : 1 if OK , 0 if error
*/
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LZ4LIB_API int LZ4_setStreamDecode ( LZ4_streamDecode_t * LZ4_streamDecode , const char * dictionary , int dictSize ) ;
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/*! LZ4_decoderRingBufferSize() : v1.8.2+
* Note : in a ring buffer scenario ( optional ) ,
* blocks are presumed decompressed next to each other
* up to the moment there is not enough remaining space for next block ( remainingSize < maxBlockSize ) ,
* at which stage it resumes from beginning of ring buffer .
* When setting such a ring buffer for streaming decompression ,
* provides the minimum size of this ring buffer
* to be compatible with any source respecting maxBlockSize condition .
* @ return : minimum ring buffer size ,
* or 0 if there is an error ( invalid maxBlockSize ) .
*/
LZ4LIB_API int LZ4_decoderRingBufferSize ( int maxBlockSize ) ;
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# define LZ4_DECODER_RING_BUFFER_SIZE(maxBlockSize) (65536 + 14 + (maxBlockSize)) /* for static allocation; maxBlockSize presumed valid */
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/*! LZ4_decompress_*_continue() :
* These decoding functions allow decompression of consecutive blocks in " streaming " mode .
* A block is an unsplittable entity , it must be presented entirely to a decompression function .
* Decompression functions only accepts one block at a time .
* The last 64 KB of previously decoded data * must * remain available and unmodified at the memory position where they were decoded .
* If less than 64 KB of data has been decoded , all the data must be present .
*
* Special : if decompression side sets a ring buffer , it must respect one of the following conditions :
* - Decompression buffer size is _at least_ LZ4_decoderRingBufferSize ( maxBlockSize ) .
* maxBlockSize is the maximum size of any single block . It can have any value > 16 bytes .
* In which case , encoding and decoding buffers do not need to be synchronized .
* Actually , data can be produced by any source compliant with LZ4 format specification , and respecting maxBlockSize .
* - Synchronized mode :
* Decompression buffer size is _exactly_ the same as compression buffer size ,
* and follows exactly same update rule ( block boundaries at same positions ) ,
* and decoding function is provided with exact decompressed size of each block ( exception for last block of the stream ) ,
* _then_ decoding & encoding ring buffer can have any size , including small ones ( < 64 KB ) .
* - Decompression buffer is larger than encoding buffer , by a minimum of maxBlockSize more bytes .
* In which case , encoding and decoding buffers do not need to be synchronized ,
* and encoding ring buffer can have any size , including small ones ( < 64 KB ) .
*
* Whenever these conditions are not possible ,
* save the last 64 KB of decoded data into a safe buffer where it can ' t be modified during decompression ,
* then indicate where this data is saved using LZ4_setStreamDecode ( ) , before decompressing next block .
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*/
LZ4LIB_API int LZ4_decompress_safe_continue ( LZ4_streamDecode_t * LZ4_streamDecode , const char * src , char * dst , int srcSize , int dstCapacity ) ;
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/*! LZ4_decompress_*_usingDict() :
* These decoding functions work the same as
* a combination of LZ4_setStreamDecode ( ) followed by LZ4_decompress_ * _continue ( )
* They are stand - alone , and don ' t need an LZ4_streamDecode_t structure .
* Dictionary is presumed stable : it must remain accessible and unmodified during decompression .
* Performance tip : Decompression speed can be substantially increased
* when dst = = dictStart + dictSize .
*/
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LZ4LIB_API int LZ4_decompress_safe_usingDict ( const char * src , char * dst , int srcSize , int dstCapcity , const char * dictStart , int dictSize ) ;
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# endif /* LZ4_H_2983827168210 */
/*^*************************************
* ! ! ! ! ! ! STATIC LINKING ONLY ! ! ! ! ! !
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/*-****************************************************************************
* Experimental section
*
* Symbols declared in this section must be considered unstable . Their
* signatures or semantics may change , or they may be removed altogether in the
* future . They are therefore only safe to depend on when the caller is
* statically linked against the library .
*
* To protect against unsafe usage , not only are the declarations guarded ,
* the definitions are hidden by default
* when building LZ4 as a shared / dynamic library .
*
* In order to access these declarations ,
* define LZ4_STATIC_LINKING_ONLY in your application
* before including LZ4 ' s headers .
*
* In order to make their implementations accessible dynamically , you must
* define LZ4_PUBLISH_STATIC_FUNCTIONS when building the LZ4 library .
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
# ifdef LZ4_STATIC_LINKING_ONLY
# ifndef LZ4_STATIC_3504398509
# define LZ4_STATIC_3504398509
# ifdef LZ4_PUBLISH_STATIC_FUNCTIONS
# define LZ4LIB_STATIC_API LZ4LIB_API
# else
# define LZ4LIB_STATIC_API
# endif
/*! LZ4_compress_fast_extState_fastReset() :
* A variant of LZ4_compress_fast_extState ( ) .
*
* Using this variant avoids an expensive initialization step .
* It is only safe to call if the state buffer is known to be correctly initialized already
* ( see above comment on LZ4_resetStream_fast ( ) for a definition of " correctly initialized " ) .
* From a high level , the difference is that
* this function initializes the provided state with a call to something like LZ4_resetStream_fast ( )
* while LZ4_compress_fast_extState ( ) starts with a call to LZ4_resetStream ( ) .
*/
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LZ4LIB_STATIC_API int LZ4_compress_fast_extState_fastReset ( void * state , const char * src , char * dst , int srcSize , int dstCapacity , int acceleration ) ;
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/*! LZ4_attach_dictionary() :
* This is an experimental API that allows
* efficient use of a static dictionary many times .
*
* Rather than re - loading the dictionary buffer into a working context before
* each compression , or copying a pre - loaded dictionary ' s LZ4_stream_t into a
* working LZ4_stream_t , this function introduces a no - copy setup mechanism ,
* in which the working stream references the dictionary stream in - place .
*
* Several assumptions are made about the state of the dictionary stream .
* Currently , only streams which have been prepared by LZ4_loadDict ( ) should
* be expected to work .
*
* Alternatively , the provided dictionaryStream may be NULL ,
* in which case any existing dictionary stream is unset .
*
* If a dictionary is provided , it replaces any pre - existing stream history .
* The dictionary contents are the only history that can be referenced and
* logically immediately precede the data compressed in the first subsequent
* compression call .
*
* The dictionary will only remain attached to the working stream through the
* first compression call , at the end of which it is cleared . The dictionary
* stream ( and source buffer ) must remain in - place / accessible / unchanged
* through the completion of the first compression call on the stream .
*/
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LZ4LIB_STATIC_API void LZ4_attach_dictionary ( LZ4_stream_t * workingStream , const LZ4_stream_t * dictionaryStream ) ;
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/*! In-place compression and decompression
*
* It ' s possible to have input and output sharing the same buffer ,
* for highly contrained memory environments .
* In both cases , it requires input to lay at the end of the buffer ,
* and decompression to start at beginning of the buffer .
* Buffer size must feature some margin , hence be larger than final size .
*
* | < - - - - - - - - - - - - - - - - - - - - - - - - buffer - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - > |
* | < - - - - - - - - - - - compressed data - - - - - - - - - > |
* | < - - - - - - - - - - - decompressed size - - - - - - - - - - - - - - - - - - > |
* | < - - - - margin - - - - > |
*
* This technique is more useful for decompression ,
* since decompressed size is typically larger ,
* and margin is short .
*
* In - place decompression will work inside any buffer
* which size is > = LZ4_DECOMPRESS_INPLACE_BUFFER_SIZE ( decompressedSize ) .
* This presumes that decompressedSize > compressedSize .
* Otherwise , it means compression actually expanded data ,
* and it would be more efficient to store such data with a flag indicating it ' s not compressed .
* This can happen when data is not compressible ( already compressed , or encrypted ) .
*
* For in - place compression , margin is larger , as it must be able to cope with both
* history preservation , requiring input data to remain unmodified up to LZ4_DISTANCE_MAX ,
* and data expansion , which can happen when input is not compressible .
* As a consequence , buffer size requirements are much higher ,
* and memory savings offered by in - place compression are more limited .
*
* There are ways to limit this cost for compression :
* - Reduce history size , by modifying LZ4_DISTANCE_MAX .
* Note that it is a compile - time constant , so all compressions will apply this limit .
* Lower values will reduce compression ratio , except when input_size < LZ4_DISTANCE_MAX ,
* so it ' s a reasonable trick when inputs are known to be small .
* - Require the compressor to deliver a " maximum compressed size " .
* This is the ` dstCapacity ` parameter in ` LZ4_compress * ( ) ` .
* When this size is < LZ4_COMPRESSBOUND ( inputSize ) , then compression can fail ,
* in which case , the return code will be 0 ( zero ) .
* The caller must be ready for these cases to happen ,
* and typically design a backup scheme to send data uncompressed .
* The combination of both techniques can significantly reduce
* the amount of margin required for in - place compression .
*
* In - place compression can work in any buffer
* which size is > = ( maxCompressedSize )
* with maxCompressedSize = = LZ4_COMPRESSBOUND ( srcSize ) for guaranteed compression success .
* LZ4_COMPRESS_INPLACE_BUFFER_SIZE ( ) depends on both maxCompressedSize and LZ4_DISTANCE_MAX ,
* so it ' s possible to reduce memory requirements by playing with them .
*/
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# define LZ4_DECOMPRESS_INPLACE_MARGIN(compressedSize) (((compressedSize) >> 8) + 32)
# define LZ4_DECOMPRESS_INPLACE_BUFFER_SIZE(decompressedSize) ((decompressedSize) + LZ4_DECOMPRESS_INPLACE_MARGIN(decompressedSize)) /**< note: presumes that compressedSize < decompressedSize. note2: margin is overestimated a bit, since it could use compressedSize instead */
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# ifndef LZ4_DISTANCE_MAX /* history window size; can be user-defined at compile time */
# define LZ4_DISTANCE_MAX 65535 /* set to maximum value by default */
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# endif
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# define LZ4_COMPRESS_INPLACE_MARGIN (LZ4_DISTANCE_MAX + 32) /* LZ4_DISTANCE_MAX can be safely replaced by srcSize when it's smaller */
# define LZ4_COMPRESS_INPLACE_BUFFER_SIZE(maxCompressedSize) ((maxCompressedSize) + LZ4_COMPRESS_INPLACE_MARGIN) /**< maxCompressedSize is generally LZ4_COMPRESSBOUND(inputSize), but can be set to any lower value, with the risk that compression can fail (return code 0(zero)) */
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# endif /* LZ4_STATIC_3504398509 */
# endif /* LZ4_STATIC_LINKING_ONLY */
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# ifndef LZ4_H_98237428734687
# define LZ4_H_98237428734687
/*-************************************************************
* PRIVATE DEFINITIONS
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* Do not use these definitions directly .
* They are only exposed to allow static allocation of ` LZ4_stream_t ` and ` LZ4_streamDecode_t ` .
* Accessing members will expose code to API and / or ABI break in future versions of the library .
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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# define LZ4_HASHLOG (LZ4_MEMORY_USAGE - 2)
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# define LZ4_HASHTABLESIZE (1 << LZ4_MEMORY_USAGE)
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# define LZ4_HASH_SIZE_U32 (1 << LZ4_HASHLOG) /* required as macro for static allocation */
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# if defined(__cplusplus) || (defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */ )
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# include <stdint.h>
typedef struct LZ4_stream_t_internal LZ4_stream_t_internal ;
struct LZ4_stream_t_internal {
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uint32_t hashTable [ LZ4_HASH_SIZE_U32 ] ;
uint32_t currentOffset ;
uint16_t dirty ;
uint16_t tableType ;
const uint8_t * dictionary ;
const LZ4_stream_t_internal * dictCtx ;
uint32_t dictSize ;
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} ;
typedef struct {
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const uint8_t * externalDict ;
size_t extDictSize ;
const uint8_t * prefixEnd ;
size_t prefixSize ;
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} LZ4_streamDecode_t_internal ;
# else
typedef struct LZ4_stream_t_internal LZ4_stream_t_internal ;
struct LZ4_stream_t_internal {
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unsigned int hashTable [ LZ4_HASH_SIZE_U32 ] ;
unsigned int currentOffset ;
unsigned short dirty ;
unsigned short tableType ;
const unsigned char * dictionary ;
const LZ4_stream_t_internal * dictCtx ;
unsigned int dictSize ;
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} ;
typedef struct {
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const unsigned char * externalDict ;
const unsigned char * prefixEnd ;
size_t extDictSize ;
size_t prefixSize ;
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} LZ4_streamDecode_t_internal ;
# endif
/*! LZ4_stream_t :
* information structure to track an LZ4 stream .
* LZ4_stream_t can also be created using LZ4_createStream ( ) , which is recommended .
* The structure definition can be convenient for static allocation
* ( on stack , or as part of larger structure ) .
* Init this structure with LZ4_initStream ( ) before first use .
* note : only use this definition in association with static linking !
* this definition is not API / ABI safe , and may change in a future version .
*/
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# define LZ4_STREAMSIZE_U64 ((1 << (LZ4_MEMORY_USAGE - 3)) + 4 + ((sizeof(void *) == 16) ? 4 : 0) /*AS-400*/ )
# define LZ4_STREAMSIZE (LZ4_STREAMSIZE_U64 * sizeof(unsigned long long))
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union LZ4_stream_u {
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unsigned long long table [ LZ4_STREAMSIZE_U64 ] ;
LZ4_stream_t_internal internal_donotuse ;
} ; /* previously typedef'd to LZ4_stream_t */
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/*! LZ4_initStream() : v1.9.0+
* An LZ4_stream_t structure must be initialized at least once .
* This is automatically done when invoking LZ4_createStream ( ) ,
* but it ' s not when the structure is simply declared on stack ( for example ) .
*
* Use LZ4_initStream ( ) to properly initialize a newly declared LZ4_stream_t .
* It can also initialize any arbitrary buffer of sufficient size ,
* and will @ return a pointer of proper type upon initialization .
*
* Note : initialization fails if size and alignment conditions are not respected .
* In which case , the function will @ return NULL .
* Note2 : An LZ4_stream_t structure guarantees correct alignment and size .
* Note3 : Before v1 .9 .0 , use LZ4_resetStream ( ) instead
*/
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LZ4LIB_API LZ4_stream_t * LZ4_initStream ( void * buffer , size_t size ) ;
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/*! LZ4_streamDecode_t :
* information structure to track an LZ4 stream during decompression .
* init this structure using LZ4_setStreamDecode ( ) before first use .
* note : only use in association with static linking !
* this definition is not API / ABI safe ,
* and may change in a future version !
*/
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# define LZ4_STREAMDECODESIZE_U64 (4 + ((sizeof(void *) == 16) ? 2 : 0) /*AS-400*/ )
# define LZ4_STREAMDECODESIZE (LZ4_STREAMDECODESIZE_U64 * sizeof(unsigned long long))
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union LZ4_streamDecode_u {
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unsigned long long table [ LZ4_STREAMDECODESIZE_U64 ] ;
LZ4_streamDecode_t_internal internal_donotuse ;
} ; /* previously typedef'd to LZ4_streamDecode_t */
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/*-************************************
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* Obsolete Functions
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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/*! Deprecation warnings
*
* Deprecated functions make the compiler generate a warning when invoked .
* This is meant to invite users to update their source code .
* Should deprecation warnings be a problem , it is generally possible to disable them ,
* typically with - Wno - deprecated - declarations for gcc
* or _CRT_SECURE_NO_WARNINGS in Visual .
*
* Another method is to define LZ4_DISABLE_DEPRECATE_WARNINGS
* before including the header file .
*/
# ifdef LZ4_DISABLE_DEPRECATE_WARNINGS
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# define LZ4_DEPRECATED(message) /* disable deprecation warnings */
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# else
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# define LZ4_GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
# if defined(__cplusplus) && (__cplusplus >= 201402) /* C++14 or greater */
# define LZ4_DEPRECATED(message) [[deprecated(message)]]
# elif (LZ4_GCC_VERSION >= 405) || defined(__clang__)
# define LZ4_DEPRECATED(message) __attribute__((deprecated(message)))
# elif (LZ4_GCC_VERSION >= 301)
# define LZ4_DEPRECATED(message) __attribute__((deprecated))
# elif defined(_MSC_VER)
# define LZ4_DEPRECATED(message) __declspec(deprecated(message))
# else
# pragma message("WARNING: You need to implement LZ4_DEPRECATED for this compiler")
# define LZ4_DEPRECATED(message)
# endif
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# endif /* LZ4_DISABLE_DEPRECATE_WARNINGS */
/* Obsolete compression functions */
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LZ4_DEPRECATED ( " use LZ4_compress_default() instead " )
LZ4LIB_API int LZ4_compress ( const char * src , char * dest , int srcSize ) ;
LZ4_DEPRECATED ( " use LZ4_compress_default() instead " )
LZ4LIB_API int LZ4_compress_limitedOutput ( const char * src , char * dest , int srcSize , int maxOutputSize ) ;
LZ4_DEPRECATED ( " use LZ4_compress_fast_extState() instead " )
LZ4LIB_API int LZ4_compress_withState ( void * state , const char * source , char * dest , int inputSize ) ;
LZ4_DEPRECATED ( " use LZ4_compress_fast_extState() instead " )
LZ4LIB_API int LZ4_compress_limitedOutput_withState ( void * state , const char * source , char * dest , int inputSize , int maxOutputSize ) ;
LZ4_DEPRECATED ( " use LZ4_compress_fast_continue() instead " )
LZ4LIB_API int LZ4_compress_continue ( LZ4_stream_t * LZ4_streamPtr , const char * source , char * dest , int inputSize ) ;
LZ4_DEPRECATED ( " use LZ4_compress_fast_continue() instead " )
LZ4LIB_API int LZ4_compress_limitedOutput_continue ( LZ4_stream_t * LZ4_streamPtr , const char * source , char * dest , int inputSize , int maxOutputSize ) ;
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/* Obsolete decompression functions */
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LZ4_DEPRECATED ( " use LZ4_decompress_fast() instead " )
LZ4LIB_API int LZ4_uncompress ( const char * source , char * dest , int outputSize ) ;
LZ4_DEPRECATED ( " use LZ4_decompress_safe() instead " )
LZ4LIB_API int LZ4_uncompress_unknownOutputSize ( const char * source , char * dest , int isize , int maxOutputSize ) ;
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/* Obsolete streaming functions; degraded functionality; do not use!
*
* In order to perform streaming compression , these functions depended on data
* that is no longer tracked in the state . They have been preserved as well as
* possible : using them will still produce a correct output . However , they don ' t
* actually retain any history between compression calls . The compression ratio
* achieved will therefore be no better than compressing each chunk
* independently .
*/
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LZ4_DEPRECATED ( " Use LZ4_createStream() instead " )
LZ4LIB_API void * LZ4_create ( char * inputBuffer ) ;
LZ4_DEPRECATED ( " Use LZ4_createStream() instead " )
LZ4LIB_API int LZ4_sizeofStreamState ( void ) ;
LZ4_DEPRECATED ( " Use LZ4_resetStream() instead " )
LZ4LIB_API int LZ4_resetStreamState ( void * state , char * inputBuffer ) ;
LZ4_DEPRECATED ( " Use LZ4_saveDict() instead " )
LZ4LIB_API char * LZ4_slideInputBuffer ( void * state ) ;
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/* Obsolete streaming decoding functions */
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LZ4_DEPRECATED ( " use LZ4_decompress_safe_usingDict() instead " )
LZ4LIB_API int LZ4_decompress_safe_withPrefix64k ( const char * src , char * dst , int compressedSize , int maxDstSize ) ;
LZ4_DEPRECATED ( " use LZ4_decompress_fast_usingDict() instead " )
LZ4LIB_API int LZ4_decompress_fast_withPrefix64k ( const char * src , char * dst , int originalSize ) ;
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/*! LZ4_decompress_fast() : **unsafe!**
* These functions used to be faster than LZ4_decompress_safe ( ) ,
* but it has changed , and they are now slower than LZ4_decompress_safe ( ) .
* This is because LZ4_decompress_fast ( ) doesn ' t know the input size ,
* and therefore must progress more cautiously in the input buffer to not read beyond the end of block .
* On top of that ` LZ4_decompress_fast ( ) ` is not protected vs malformed or malicious inputs , making it a security liability .
* As a consequence , LZ4_decompress_fast ( ) is strongly discouraged , and deprecated .
*
* The last remaining LZ4_decompress_fast ( ) specificity is that
* it can decompress a block without knowing its compressed size .
* Such functionality could be achieved in a more secure manner ,
* by also providing the maximum size of input buffer ,
* but it would require new prototypes , and adaptation of the implementation to this new use case .
*
* Parameters :
* originalSize : is the uncompressed size to regenerate .
* ` dst ` must be already allocated , its size must be > = ' originalSize ' bytes .
* @ return : number of bytes read from source buffer ( = = compressed size ) .
* The function expects to finish at block ' s end exactly .
* If the source stream is detected malformed , the function stops decoding and returns a negative result .
* note : LZ4_decompress_fast * ( ) requires originalSize . Thanks to this information , it never writes past the output buffer .
* However , since it doesn ' t know its ' src ' size , it may read an unknown amount of input , past input buffer bounds .
* Also , since match offsets are not validated , match reads from ' src ' may underflow too .
* These issues never happen if input ( compressed ) data is correct .
* But they may happen if input data is invalid ( error or intentional tampering ) .
* As a consequence , use these functions in trusted environments with trusted data * * only * * .
*/
LZ4_DEPRECATED ( " This function is deprecated and unsafe. Consider using LZ4_decompress_safe() instead " )
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LZ4LIB_API int LZ4_decompress_fast ( const char * src , char * dst , int originalSize ) ;
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LZ4_DEPRECATED ( " This function is deprecated and unsafe. Consider using LZ4_decompress_safe_continue() instead " )
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LZ4LIB_API int LZ4_decompress_fast_continue ( LZ4_streamDecode_t * LZ4_streamDecode , const char * src , char * dst , int originalSize ) ;
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LZ4_DEPRECATED ( " This function is deprecated and unsafe. Consider using LZ4_decompress_safe_usingDict() instead " )
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LZ4LIB_API int LZ4_decompress_fast_usingDict ( const char * src , char * dst , int originalSize , const char * dictStart , int dictSize ) ;
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/*! LZ4_resetStream() :
* An LZ4_stream_t structure must be initialized at least once .
* This is done with LZ4_initStream ( ) , or LZ4_resetStream ( ) .
* Consider switching to LZ4_initStream ( ) ,
* invoking LZ4_resetStream ( ) will trigger deprecation warnings in the future .
*/
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LZ4LIB_API void LZ4_resetStream ( LZ4_stream_t * streamPtr ) ;
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# endif /* LZ4_H_98237428734687 */
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# if defined(__cplusplus)
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}
# endif