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/*
LZ4 auto - framing library
Header File
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Copyright ( C ) 2011 - 2020 , Yann Collet .
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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 :
* Redistributions of source code must retain the above copyright
notice , this list of conditions and the following disclaimer .
* Redistributions in binary form must reproduce the above
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 :
- LZ4 source repository : https : //github.com/lz4/lz4
- LZ4 public forum : https : //groups.google.com/forum/#!forum/lz4c
*/
/* LZ4F is a stand-alone API able to create and decode LZ4 frames
* conformant with specification v1 .6 .1 in doc / lz4_Frame_format . md .
* Generated frames are compatible with ` lz4 ` CLI .
*
* LZ4F also offers streaming capabilities .
*
* lz4 . h is not required when using lz4frame . h ,
* except to extract common constant such as LZ4_VERSION_NUMBER .
* */
# ifndef LZ4F_H_09782039843
# define LZ4F_H_09782039843
# if defined (__cplusplus)
extern " C " {
# endif
/* --- Dependency --- */
# include <stddef.h> /* size_t */
/**
Introduction
lz4frame . h implements LZ4 frame specification ( doc / lz4_Frame_format . md ) .
lz4frame . h provides frame compression functions that take care
of encoding standard metadata alongside LZ4 - compressed blocks .
*/
/*-***************************************************************
* Compiler specifics
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/* LZ4_DLL_EXPORT :
* Enable exporting of functions when building a Windows DLL
* LZ4FLIB_VISIBILITY :
* Control library symbols visibility .
*/
# ifndef LZ4FLIB_VISIBILITY
# if defined(__GNUC__) && (__GNUC__ >= 4)
# define LZ4FLIB_VISIBILITY __attribute__ ((visibility ("default")))
# else
# define LZ4FLIB_VISIBILITY
# endif
# endif
# if defined(LZ4_DLL_EXPORT) && (LZ4_DLL_EXPORT==1)
# define LZ4FLIB_API __declspec(dllexport) LZ4FLIB_VISIBILITY
# elif defined(LZ4_DLL_IMPORT) && (LZ4_DLL_IMPORT==1)
# define LZ4FLIB_API __declspec(dllimport) LZ4FLIB_VISIBILITY
# else
# define LZ4FLIB_API LZ4FLIB_VISIBILITY
# endif
# ifdef LZ4F_DISABLE_DEPRECATE_WARNINGS
# define LZ4F_DEPRECATE(x) x
# else
# if defined(_MSC_VER)
# define LZ4F_DEPRECATE(x) x /* __declspec(deprecated) x - only works with C++ */
# elif defined(__clang__) || (defined(__GNUC__) && (__GNUC__ >= 6))
# define LZ4F_DEPRECATE(x) x __attribute__((deprecated))
# else
# define LZ4F_DEPRECATE(x) x /* no deprecation warning for this compiler */
# endif
# endif
/*-************************************
* Error management
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
typedef size_t LZ4F_errorCode_t ;
LZ4FLIB_API unsigned LZ4F_isError ( LZ4F_errorCode_t code ) ; /**< tells when a function result is an error code */
LZ4FLIB_API const char * LZ4F_getErrorName ( LZ4F_errorCode_t code ) ; /**< return error code string; for debugging */
/*-************************************
* Frame compression types
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* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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/* #define LZ4F_ENABLE_OBSOLETE_ENUMS // uncomment to enable obsolete enums */
# ifdef LZ4F_ENABLE_OBSOLETE_ENUMS
# define LZ4F_OBSOLETE_ENUM(x) , LZ4F_DEPRECATE(x) = LZ4F_##x
# else
# define LZ4F_OBSOLETE_ENUM(x)
# endif
/* The larger the block size, the (slightly) better the compression ratio,
* though there are diminishing returns .
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* Larger blocks also increase memory usage on both compression and decompression sides .
*/
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typedef enum {
LZ4F_default = 0 ,
LZ4F_max64KB = 4 ,
LZ4F_max256KB = 5 ,
LZ4F_max1MB = 6 ,
LZ4F_max4MB = 7
LZ4F_OBSOLETE_ENUM ( max64KB )
LZ4F_OBSOLETE_ENUM ( max256KB )
LZ4F_OBSOLETE_ENUM ( max1MB )
LZ4F_OBSOLETE_ENUM ( max4MB )
} LZ4F_blockSizeID_t ;
/* Linked blocks sharply reduce inefficiencies when using small blocks,
* they compress better .
* However , some LZ4 decoders are only compatible with independent blocks */
typedef enum {
LZ4F_blockLinked = 0 ,
LZ4F_blockIndependent
LZ4F_OBSOLETE_ENUM ( blockLinked )
LZ4F_OBSOLETE_ENUM ( blockIndependent )
} LZ4F_blockMode_t ;
typedef enum {
LZ4F_noContentChecksum = 0 ,
LZ4F_contentChecksumEnabled
LZ4F_OBSOLETE_ENUM ( noContentChecksum )
LZ4F_OBSOLETE_ENUM ( contentChecksumEnabled )
} LZ4F_contentChecksum_t ;
typedef enum {
LZ4F_noBlockChecksum = 0 ,
LZ4F_blockChecksumEnabled
} LZ4F_blockChecksum_t ;
typedef enum {
LZ4F_frame = 0 ,
LZ4F_skippableFrame
LZ4F_OBSOLETE_ENUM ( skippableFrame )
} LZ4F_frameType_t ;
# ifdef LZ4F_ENABLE_OBSOLETE_ENUMS
typedef LZ4F_blockSizeID_t blockSizeID_t ;
typedef LZ4F_blockMode_t blockMode_t ;
typedef LZ4F_frameType_t frameType_t ;
typedef LZ4F_contentChecksum_t contentChecksum_t ;
# endif
/*! LZ4F_frameInfo_t :
* makes it possible to set or read frame parameters .
* Structure must be first init to 0 , using memset ( ) or LZ4F_INIT_FRAMEINFO ,
* setting all parameters to default .
* It ' s then possible to update selectively some parameters */
typedef struct {
LZ4F_blockSizeID_t blockSizeID ; /* max64KB, max256KB, max1MB, max4MB; 0 == default */
LZ4F_blockMode_t blockMode ; /* LZ4F_blockLinked, LZ4F_blockIndependent; 0 == default */
LZ4F_contentChecksum_t contentChecksumFlag ; /* 1: frame terminated with 32-bit checksum of decompressed data; 0: disabled (default) */
LZ4F_frameType_t frameType ; /* read-only field : LZ4F_frame or LZ4F_skippableFrame */
unsigned long long contentSize ; /* Size of uncompressed content ; 0 == unknown */
unsigned dictID ; /* Dictionary ID, sent by compressor to help decoder select correct dictionary; 0 == no dictID provided */
LZ4F_blockChecksum_t blockChecksumFlag ; /* 1: each block followed by a checksum of block's compressed data; 0: disabled (default) */
} LZ4F_frameInfo_t ;
# define LZ4F_INIT_FRAMEINFO { LZ4F_default, LZ4F_blockLinked, LZ4F_noContentChecksum, LZ4F_frame, 0ULL, 0U, LZ4F_noBlockChecksum } /* v1.8.3+ */
/*! LZ4F_preferences_t :
* makes it possible to supply advanced compression instructions to streaming interface .
* Structure must be first init to 0 , using memset ( ) or LZ4F_INIT_PREFERENCES ,
* setting all parameters to default .
* All reserved fields must be set to zero . */
typedef struct {
LZ4F_frameInfo_t frameInfo ;
int compressionLevel ; /* 0: default (fast mode); values > LZ4HC_CLEVEL_MAX count as LZ4HC_CLEVEL_MAX; values < 0 trigger "fast acceleration" */
unsigned autoFlush ; /* 1: always flush; reduces usage of internal buffers */
unsigned favorDecSpeed ; /* 1: parser favors decompression speed vs compression ratio. Only works for high compression modes (>= LZ4HC_CLEVEL_OPT_MIN) */ /* v1.8.2+ */
unsigned reserved [ 3 ] ; /* must be zero for forward compatibility */
} LZ4F_preferences_t ;
# define LZ4F_INIT_PREFERENCES { LZ4F_INIT_FRAMEINFO, 0, 0u, 0u, { 0u, 0u, 0u } } /* v1.8.3+ */
/*-*********************************
* Simple compression function
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
LZ4FLIB_API int LZ4F_compressionLevel_max ( void ) ; /* v1.8.0+ */
/*! LZ4F_compressFrameBound() :
* Returns the maximum possible compressed size with LZ4F_compressFrame ( ) given srcSize and preferences .
* ` preferencesPtr ` is optional . It can be replaced by NULL , in which case , the function will assume default preferences .
* Note : this result is only usable with LZ4F_compressFrame ( ) .
* It may also be used with LZ4F_compressUpdate ( ) _if no flush ( ) operation_ is performed .
*/
LZ4FLIB_API size_t LZ4F_compressFrameBound ( size_t srcSize , const LZ4F_preferences_t * preferencesPtr ) ;
/*! LZ4F_compressFrame() :
* Compress an entire srcBuffer into a valid LZ4 frame .
* dstCapacity MUST be > = LZ4F_compressFrameBound ( srcSize , preferencesPtr ) .
* The LZ4F_preferences_t structure is optional : you can provide NULL as argument . All preferences will be set to default .
* @ return : number of bytes written into dstBuffer .
* or an error code if it fails ( can be tested using LZ4F_isError ( ) )
*/
LZ4FLIB_API size_t LZ4F_compressFrame ( void * dstBuffer , size_t dstCapacity ,
const void * srcBuffer , size_t srcSize ,
const LZ4F_preferences_t * preferencesPtr ) ;
/*-***********************************
* Advanced compression functions
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
typedef struct LZ4F_cctx_s LZ4F_cctx ; /* incomplete type */
typedef LZ4F_cctx * LZ4F_compressionContext_t ; /* for compatibility with previous API version */
typedef struct {
unsigned stableSrc ; /* 1 == src content will remain present on future calls to LZ4F_compress(); skip copying src content within tmp buffer */
unsigned reserved [ 3 ] ;
} LZ4F_compressOptions_t ;
/*--- Resource Management ---*/
# define LZ4F_VERSION 100 /* This number can be used to check for an incompatible API breaking change */
LZ4FLIB_API unsigned LZ4F_getVersion ( void ) ;
/*! LZ4F_createCompressionContext() :
* The first thing to do is to create a compressionContext object , which will be used in all compression operations .
* This is achieved using LZ4F_createCompressionContext ( ) , which takes as argument a version .
* The version provided MUST be LZ4F_VERSION . It is intended to track potential version mismatch , notably when using DLL .
* The function will provide a pointer to a fully allocated LZ4F_cctx object .
* If @ return ! = zero , there was an error during context creation .
* Object can release its memory using LZ4F_freeCompressionContext ( ) ;
*/
LZ4FLIB_API LZ4F_errorCode_t LZ4F_createCompressionContext ( LZ4F_cctx * * cctxPtr , unsigned version ) ;
LZ4FLIB_API LZ4F_errorCode_t LZ4F_freeCompressionContext ( LZ4F_cctx * cctx ) ;
/*---- Compression ----*/
# define LZ4F_HEADER_SIZE_MIN 7 /* LZ4 Frame header size can vary, depending on selected paramaters */
# define LZ4F_HEADER_SIZE_MAX 19
/* Size in bytes of a block header in little-endian format. Highest bit indicates if block data is uncompressed */
# define LZ4F_BLOCK_HEADER_SIZE 4
/* Size in bytes of a block checksum footer in little-endian format. */
# define LZ4F_BLOCK_CHECKSUM_SIZE 4
/* Size in bytes of the content checksum. */
# define LZ4F_CONTENT_CHECKSUM_SIZE 4
/*! LZ4F_compressBegin() :
* will write the frame header into dstBuffer .
* dstCapacity must be > = LZ4F_HEADER_SIZE_MAX bytes .
* ` prefsPtr ` is optional : you can provide NULL as argument , all preferences will then be set to default .
* @ return : number of bytes written into dstBuffer for the header
* or an error code ( which can be tested using LZ4F_isError ( ) )
*/
LZ4FLIB_API size_t LZ4F_compressBegin ( LZ4F_cctx * cctx ,
void * dstBuffer , size_t dstCapacity ,
const LZ4F_preferences_t * prefsPtr ) ;
/*! LZ4F_compressBound() :
* Provides minimum dstCapacity required to guarantee success of
* LZ4F_compressUpdate ( ) , given a srcSize and preferences , for a worst case scenario .
* When srcSize = = 0 , LZ4F_compressBound ( ) provides an upper bound for LZ4F_flush ( ) and LZ4F_compressEnd ( ) instead .
* Note that the result is only valid for a single invocation of LZ4F_compressUpdate ( ) .
* When invoking LZ4F_compressUpdate ( ) multiple times ,
* if the output buffer is gradually filled up instead of emptied and re - used from its start ,
* one must check if there is enough remaining capacity before each invocation , using LZ4F_compressBound ( ) .
* @ return is always the same for a srcSize and prefsPtr .
* prefsPtr is optional : when NULL is provided , preferences will be set to cover worst case scenario .
* tech details :
* @ return if automatic flushing is not enabled , includes the possibility that internal buffer might already be filled by up to ( blockSize - 1 ) bytes .
* It also includes frame footer ( ending + checksum ) , since it might be generated by LZ4F_compressEnd ( ) .
* @ return doesn ' t include frame header , as it was already generated by LZ4F_compressBegin ( ) .
*/
LZ4FLIB_API size_t LZ4F_compressBound ( size_t srcSize , const LZ4F_preferences_t * prefsPtr ) ;
/*! LZ4F_compressUpdate() :
* LZ4F_compressUpdate ( ) can be called repetitively to compress as much data as necessary .
* Important rule : dstCapacity MUST be large enough to ensure operation success even in worst case situations .
* This value is provided by LZ4F_compressBound ( ) .
* If this condition is not respected , LZ4F_compress ( ) will fail ( result is an errorCode ) .
* LZ4F_compressUpdate ( ) doesn ' t guarantee error recovery .
* When an error occurs , compression context must be freed or resized .
* ` cOptPtr ` is optional : NULL can be provided , in which case all options are set to default .
* @ return : number of bytes written into ` dstBuffer ` ( it can be zero , meaning input data was just buffered ) .
* or an error code if it fails ( which can be tested using LZ4F_isError ( ) )
*/
LZ4FLIB_API size_t LZ4F_compressUpdate ( LZ4F_cctx * cctx ,
void * dstBuffer , size_t dstCapacity ,
const void * srcBuffer , size_t srcSize ,
const LZ4F_compressOptions_t * cOptPtr ) ;
/*! LZ4F_flush() :
* When data must be generated and sent immediately , without waiting for a block to be completely filled ,
* it ' s possible to call LZ4_flush ( ) . It will immediately compress any data buffered within cctx .
* ` dstCapacity ` must be large enough to ensure the operation will be successful .
* ` cOptPtr ` is optional : it ' s possible to provide NULL , all options will be set to default .
* @ return : nb of bytes written into dstBuffer ( can be zero , when there is no data stored within cctx )
* or an error code if it fails ( which can be tested using LZ4F_isError ( ) )
* Note : LZ4F_flush ( ) is guaranteed to be successful when dstCapacity > = LZ4F_compressBound ( 0 , prefsPtr ) .
*/
LZ4FLIB_API size_t LZ4F_flush ( LZ4F_cctx * cctx ,
void * dstBuffer , size_t dstCapacity ,
const LZ4F_compressOptions_t * cOptPtr ) ;
/*! LZ4F_compressEnd() :
* To properly finish an LZ4 frame , invoke LZ4F_compressEnd ( ) .
* It will flush whatever data remained within ` cctx ` ( like LZ4_flush ( ) )
* and properly finalize the frame , with an endMark and a checksum .
* ` cOptPtr ` is optional : NULL can be provided , in which case all options will be set to default .
* @ return : nb of bytes written into dstBuffer , necessarily > = 4 ( endMark ) ,
* or an error code if it fails ( which can be tested using LZ4F_isError ( ) )
* Note : LZ4F_compressEnd ( ) is guaranteed to be successful when dstCapacity > = LZ4F_compressBound ( 0 , prefsPtr ) .
* A successful call to LZ4F_compressEnd ( ) makes ` cctx ` available again for another compression task .
*/
LZ4FLIB_API size_t LZ4F_compressEnd ( LZ4F_cctx * cctx ,
void * dstBuffer , size_t dstCapacity ,
const LZ4F_compressOptions_t * cOptPtr ) ;
/*-*********************************
* Decompression functions
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
typedef struct LZ4F_dctx_s LZ4F_dctx ; /* incomplete type */
typedef LZ4F_dctx * LZ4F_decompressionContext_t ; /* compatibility with previous API versions */
typedef struct {
unsigned stableDst ; /* pledges that last 64KB decompressed data will remain available unmodified. This optimization skips storage operations in tmp buffers. */
unsigned reserved [ 3 ] ; /* must be set to zero for forward compatibility */
} LZ4F_decompressOptions_t ;
/* Resource management */
/*! LZ4F_createDecompressionContext() :
* Create an LZ4F_dctx object , to track all decompression operations .
* The version provided MUST be LZ4F_VERSION .
* The function provides a pointer to an allocated and initialized LZ4F_dctx object .
* The result is an errorCode , which can be tested using LZ4F_isError ( ) .
* dctx memory can be released using LZ4F_freeDecompressionContext ( ) ;
* Result of LZ4F_freeDecompressionContext ( ) indicates current state of decompressionContext when being released .
* That is , it should be = = 0 if decompression has been completed fully and correctly .
*/
LZ4FLIB_API LZ4F_errorCode_t LZ4F_createDecompressionContext ( LZ4F_dctx * * dctxPtr , unsigned version ) ;
LZ4FLIB_API LZ4F_errorCode_t LZ4F_freeDecompressionContext ( LZ4F_dctx * dctx ) ;
/*-***********************************
* Streaming decompression functions
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
# define LZ4F_MIN_SIZE_TO_KNOW_HEADER_LENGTH 5
/*! LZ4F_headerSize() : v1.9.0+
* Provide the header size of a frame starting at ` src ` .
* ` srcSize ` must be > = LZ4F_MIN_SIZE_TO_KNOW_HEADER_LENGTH ,
* which is enough to decode the header length .
* @ return : size of frame header
* or an error code , which can be tested using LZ4F_isError ( )
* note : Frame header size is variable , but is guaranteed to be
* > = LZ4F_HEADER_SIZE_MIN bytes , and < = LZ4F_HEADER_SIZE_MAX bytes .
*/
LZ4FLIB_API size_t LZ4F_headerSize ( const void * src , size_t srcSize ) ;
/*! LZ4F_getFrameInfo() :
* This function extracts frame parameters ( max blockSize , dictID , etc . ) .
* Its usage is optional : user can call LZ4F_decompress ( ) directly .
*
* Extracted information will fill an existing LZ4F_frameInfo_t structure .
* This can be useful for allocation and dictionary identification purposes .
*
* LZ4F_getFrameInfo ( ) can work in the following situations :
*
* 1 ) At the beginning of a new frame , before any invocation of LZ4F_decompress ( ) .
* It will decode header from ` srcBuffer ` ,
* consuming the header and starting the decoding process .
*
* Input size must be large enough to contain the full frame header .
* Frame header size can be known beforehand by LZ4F_headerSize ( ) .
* Frame header size is variable , but is guaranteed to be > = LZ4F_HEADER_SIZE_MIN bytes ,
* and not more than < = LZ4F_HEADER_SIZE_MAX bytes .
* Hence , blindly providing LZ4F_HEADER_SIZE_MAX bytes or more will always work .
* It ' s allowed to provide more input data than the header size ,
* LZ4F_getFrameInfo ( ) will only consume the header .
*
* If input size is not large enough ,
* aka if it ' s smaller than header size ,
* function will fail and return an error code .
*
* 2 ) After decoding has been started ,
* it ' s possible to invoke LZ4F_getFrameInfo ( ) anytime
* to extract already decoded frame parameters stored within dctx .
*
* Note that , if decoding has barely started ,
* and not yet read enough information to decode the header ,
* LZ4F_getFrameInfo ( ) will fail .
*
* The number of bytes consumed from srcBuffer will be updated in * srcSizePtr ( necessarily < = original value ) .
* LZ4F_getFrameInfo ( ) only consumes bytes when decoding has not yet started ,
* and when decoding the header has been successful .
* Decompression must then resume from ( srcBuffer + * srcSizePtr ) .
*
* @ return : a hint about how many srcSize bytes LZ4F_decompress ( ) expects for next call ,
* or an error code which can be tested using LZ4F_isError ( ) .
* note 1 : in case of error , dctx is not modified . Decoding operation can resume from beginning safely .
* note 2 : frame parameters are * copied into * an already allocated LZ4F_frameInfo_t structure .
*/
LZ4FLIB_API size_t LZ4F_getFrameInfo ( LZ4F_dctx * dctx ,
LZ4F_frameInfo_t * frameInfoPtr ,
const void * srcBuffer , size_t * srcSizePtr ) ;
/*! LZ4F_decompress() :
* Call this function repetitively to regenerate data compressed in ` srcBuffer ` .
*
* The function requires a valid dctx state .
* It will read up to * srcSizePtr bytes from srcBuffer ,
* and decompress data into dstBuffer , of capacity * dstSizePtr .
*
* The nb of bytes consumed from srcBuffer will be written into * srcSizePtr ( necessarily < = original value ) .
* The nb of bytes decompressed into dstBuffer will be written into * dstSizePtr ( necessarily < = original value ) .
*
* The function does not necessarily read all input bytes , so always check value in * srcSizePtr .
* Unconsumed source data must be presented again in subsequent invocations .
*
* ` dstBuffer ` can freely change between each consecutive function invocation .
* ` dstBuffer ` content will be overwritten .
*
* @ return : an hint of how many ` srcSize ` bytes LZ4F_decompress ( ) expects for next call .
* Schematically , it ' s the size of the current ( or remaining ) compressed block + header of next block .
* Respecting the hint provides some small speed benefit , because it skips intermediate buffers .
* This is just a hint though , it ' s always possible to provide any srcSize .
*
* When a frame is fully decoded , @ return will be 0 ( no more data expected ) .
* When provided with more bytes than necessary to decode a frame ,
* LZ4F_decompress ( ) will stop reading exactly at end of current frame , and @ return 0.
*
* If decompression failed , @ return is an error code , which can be tested using LZ4F_isError ( ) .
* After a decompression error , the ` dctx ` context is not resumable .
* Use LZ4F_resetDecompressionContext ( ) to return to clean state .
*
* After a frame is fully decoded , dctx can be used again to decompress another frame .
*/
LZ4FLIB_API size_t LZ4F_decompress ( LZ4F_dctx * dctx ,
void * dstBuffer , size_t * dstSizePtr ,
const void * srcBuffer , size_t * srcSizePtr ,
const LZ4F_decompressOptions_t * dOptPtr ) ;
/*! LZ4F_resetDecompressionContext() : added in v1.8.0
* In case of an error , the context is left in " undefined " state .
* In which case , it ' s necessary to reset it , before re - using it .
* This method can also be used to abruptly stop any unfinished decompression ,
* and start a new one using same context resources . */
LZ4FLIB_API void LZ4F_resetDecompressionContext ( LZ4F_dctx * dctx ) ; /* always successful */
# if defined (__cplusplus)
}
# endif
# endif /* LZ4F_H_09782039843 */
# if defined(LZ4F_STATIC_LINKING_ONLY) && !defined(LZ4F_H_STATIC_09782039843)
# define LZ4F_H_STATIC_09782039843
# if defined (__cplusplus)
extern " C " {
# endif
/* These declarations are not stable and may change in the future.
* They are therefore only safe to depend on
* when the caller is statically linked against the library .
* To access their declarations , define LZ4F_STATIC_LINKING_ONLY .
*
* By default , these symbols aren ' t published into shared / dynamic libraries .
* You can override this behavior and force them to be published
* by defining LZ4F_PUBLISH_STATIC_FUNCTIONS .
* Use at your own risk .
*/
# ifdef LZ4F_PUBLISH_STATIC_FUNCTIONS
# define LZ4FLIB_STATIC_API LZ4FLIB_API
# else
# define LZ4FLIB_STATIC_API
# endif
/* --- Error List --- */
# define LZ4F_LIST_ERRORS(ITEM) \
ITEM ( OK_NoError ) \
ITEM ( ERROR_GENERIC ) \
ITEM ( ERROR_maxBlockSize_invalid ) \
ITEM ( ERROR_blockMode_invalid ) \
ITEM ( ERROR_contentChecksumFlag_invalid ) \
ITEM ( ERROR_compressionLevel_invalid ) \
ITEM ( ERROR_headerVersion_wrong ) \
ITEM ( ERROR_blockChecksum_invalid ) \
ITEM ( ERROR_reservedFlag_set ) \
ITEM ( ERROR_allocation_failed ) \
ITEM ( ERROR_srcSize_tooLarge ) \
ITEM ( ERROR_dstMaxSize_tooSmall ) \
ITEM ( ERROR_frameHeader_incomplete ) \
ITEM ( ERROR_frameType_unknown ) \
ITEM ( ERROR_frameSize_wrong ) \
ITEM ( ERROR_srcPtr_wrong ) \
ITEM ( ERROR_decompressionFailed ) \
ITEM ( ERROR_headerChecksum_invalid ) \
ITEM ( ERROR_contentChecksum_invalid ) \
ITEM ( ERROR_frameDecoding_alreadyStarted ) \
ITEM ( ERROR_maxCode )
# define LZ4F_GENERATE_ENUM(ENUM) LZ4F_##ENUM,
/* enum list is exposed, to handle specific errors */
typedef enum { LZ4F_LIST_ERRORS ( LZ4F_GENERATE_ENUM )
_LZ4F_dummy_error_enum_for_c89_never_used } LZ4F_errorCodes ;
LZ4FLIB_STATIC_API LZ4F_errorCodes LZ4F_getErrorCode ( size_t functionResult ) ;
LZ4FLIB_STATIC_API size_t LZ4F_getBlockSize ( unsigned ) ;
/**********************************
* Bulk processing dictionary API
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/* A Dictionary is useful for the compression of small messages (KB range).
* It dramatically improves compression efficiency .
*
* LZ4 can ingest any input as dictionary , though only the last 64 KB are useful .
* Best results are generally achieved by using Zstandard ' s Dictionary Builder
* to generate a high - quality dictionary from a set of samples .
*
* Loading a dictionary has a cost , since it involves construction of tables .
* The Bulk processing dictionary API makes it possible to share this cost
* over an arbitrary number of compression jobs , even concurrently ,
* markedly improving compression latency for these cases .
*
* The same dictionary will have to be used on the decompression side
* for decoding to be successful .
* To help identify the correct dictionary at decoding stage ,
* the frame header allows optional embedding of a dictID field .
*/
typedef struct LZ4F_CDict_s LZ4F_CDict ;
/*! LZ4_createCDict() :
* When compressing multiple messages / blocks using the same dictionary , it ' s recommended to load it just once .
* LZ4_createCDict ( ) will create a digested dictionary , ready to start future compression operations without startup delay .
* LZ4_CDict can be created once and shared by multiple threads concurrently , since its usage is read - only .
* ` dictBuffer ` can be released after LZ4_CDict creation , since its content is copied within CDict */
LZ4FLIB_STATIC_API LZ4F_CDict * LZ4F_createCDict ( const void * dictBuffer , size_t dictSize ) ;
LZ4FLIB_STATIC_API void LZ4F_freeCDict ( LZ4F_CDict * CDict ) ;
/*! LZ4_compressFrame_usingCDict() :
* Compress an entire srcBuffer into a valid LZ4 frame using a digested Dictionary .
* cctx must point to a context created by LZ4F_createCompressionContext ( ) .
* If cdict = = NULL , compress without a dictionary .
* dstBuffer MUST be > = LZ4F_compressFrameBound ( srcSize , preferencesPtr ) .
* If this condition is not respected , function will fail ( @ return an errorCode ) .
* The LZ4F_preferences_t structure is optional : you may provide NULL as argument ,
* but it ' s not recommended , as it ' s the only way to provide dictID in the frame header .
* @ return : number of bytes written into dstBuffer .
* or an error code if it fails ( can be tested using LZ4F_isError ( ) ) */
LZ4FLIB_STATIC_API size_t LZ4F_compressFrame_usingCDict (
LZ4F_cctx * cctx ,
void * dst , size_t dstCapacity ,
const void * src , size_t srcSize ,
const LZ4F_CDict * cdict ,
const LZ4F_preferences_t * preferencesPtr ) ;
/*! LZ4F_compressBegin_usingCDict() :
* Inits streaming dictionary compression , and writes the frame header into dstBuffer .
* dstCapacity must be > = LZ4F_HEADER_SIZE_MAX bytes .
* ` prefsPtr ` is optional : you may provide NULL as argument ,
* however , it ' s the only way to provide dictID in the frame header .
* @ return : number of bytes written into dstBuffer for the header ,
* or an error code ( which can be tested using LZ4F_isError ( ) ) */
LZ4FLIB_STATIC_API size_t LZ4F_compressBegin_usingCDict (
LZ4F_cctx * cctx ,
void * dstBuffer , size_t dstCapacity ,
const LZ4F_CDict * cdict ,
const LZ4F_preferences_t * prefsPtr ) ;
/*! LZ4F_decompress_usingDict() :
* Same as LZ4F_decompress ( ) , using a predefined dictionary .
* Dictionary is used " in place " , without any preprocessing .
* It must remain accessible throughout the entire frame decoding . */
LZ4FLIB_STATIC_API size_t LZ4F_decompress_usingDict (
LZ4F_dctx * dctxPtr ,
void * dstBuffer , size_t * dstSizePtr ,
const void * srcBuffer , size_t * srcSizePtr ,
const void * dict , size_t dictSize ,
const LZ4F_decompressOptions_t * decompressOptionsPtr ) ;
# if defined (__cplusplus)
}
# endif
# endif /* defined(LZ4F_STATIC_LINKING_ONLY) && !defined(LZ4F_H_STATIC_09782039843) */