zstd_v04.h File Reference

#include <stddef.h>

Go to the source code of this file.

Macros
#define	ZSTDv04_magicNumber   0xFD2FB524 /* v0.4 */

Typedefs
typedef struct ZSTDv04_Dctx_s	ZSTDv04_Dctx
typedef struct ZBUFFv04_DCtx_s	ZBUFFv04_DCtx

Functions
size_t	ZSTDv04_decompress (void *dst, size_t maxOriginalSize, const void *src, size_t compressedSize)
void	ZSTDv04_findFrameSizeInfoLegacy (const void *src, size_t srcSize, size_t *cSize, unsigned long long *dBound)
unsigned	ZSTDv04_isError (size_t code)
ZSTDv04_Dctx *	ZSTDv04_createDCtx (void)
size_t	ZSTDv04_freeDCtx (ZSTDv04_Dctx *dctx)
size_t	ZSTDv04_decompressDCtx (ZSTDv04_Dctx *dctx, void *dst, size_t maxOriginalSize, const void *src, size_t compressedSize)
size_t	ZSTDv04_resetDCtx (ZSTDv04_Dctx *dctx)
size_t	ZSTDv04_nextSrcSizeToDecompress (ZSTDv04_Dctx *dctx)
size_t	ZSTDv04_decompressContinue (ZSTDv04_Dctx *dctx, void *dst, size_t maxDstSize, const void *src, size_t srcSize)
ZBUFFv04_DCtx *	ZBUFFv04_createDCtx (void)
size_t	ZBUFFv04_freeDCtx (ZBUFFv04_DCtx *dctx)
size_t	ZBUFFv04_decompressInit (ZBUFFv04_DCtx *dctx)
size_t	ZBUFFv04_decompressWithDictionary (ZBUFFv04_DCtx *dctx, const void *dict, size_t dictSize)
size_t	ZBUFFv04_decompressContinue (ZBUFFv04_DCtx *dctx, void *dst, size_t *maxDstSizePtr, const void *src, size_t *srcSizePtr)
unsigned	ZBUFFv04_isError (size_t errorCode)
const char *	ZBUFFv04_getErrorName (size_t errorCode)
size_t	ZBUFFv04_recommendedDInSize (void)
size_t	ZBUFFv04_recommendedDOutSize (void)

Macro Definition Documentation

ZSTDv04_magicNumber

#define ZSTDv04_magicNumber   0xFD2FB524 /* v0.4 */

Typedef Documentation

ZBUFFv04_DCtx

typedef struct ZBUFFv04_DCtx_s ZBUFFv04_DCtx

Use above functions alternatively. ZSTD_nextSrcSizeToDecompress() tells how much bytes to provide as 'srcSize' to ZSTD_decompressContinue(). ZSTD_decompressContinue() will use previous data blocks to improve compression if they are located prior to current block. Result is the number of bytes regenerated within 'dst'. It can be zero, which is not an error; it just means ZSTD_decompressContinue() has decoded some header.

ZSTDv04_Dctx

typedef struct ZSTDv04_Dctx_s ZSTDv04_Dctx

Function Documentation

ZBUFFv04_createDCtx()

ZBUFFv04_DCtx * ZBUFFv04_createDCtx

(

void

)

ZBUFFv04_decompressContinue()

size_t ZBUFFv04_decompressContinue	(	ZBUFFv04_DCtx *	dctx,
		void *	dst,
		size_t *	maxDstSizePtr,
		const void *	src,
		size_t *	srcSizePtr )

ZBUFFv04_decompressInit()

size_t ZBUFFv04_decompressInit

(

ZBUFFv04_DCtx *

dctx

)

ZBUFFv04_decompressWithDictionary()

size_t ZBUFFv04_decompressWithDictionary	(	ZBUFFv04_DCtx *	dctx,
		const void *	dict,
		size_t	dictSize )

ZBUFFv04_freeDCtx()

size_t ZBUFFv04_freeDCtx

(

ZBUFFv04_DCtx *

dctx

)

ZBUFFv04_getErrorName()

const char * ZBUFFv04_getErrorName

(

size_t

errorCode

)

ZBUFFv04_isError()

unsigned ZBUFFv04_isError

(

size_t

errorCode

)

---

Streaming decompression

A ZBUFF_DCtx object is required to track streaming operation. Use ZBUFF_createDCtx() and ZBUFF_freeDCtx() to create/release resources. Use ZBUFF_decompressInit() to start a new decompression operation. ZBUFF_DCtx objects can be reused multiple times.

Optionally, a reference to a static dictionary can be set, using ZBUFF_decompressWithDictionary() It must be the same content as the one set during compression phase. Dictionary content must remain accessible during the decompression process.

Use ZBUFF_decompressContinue() repetitively to consume your input. *srcSizePtr and *maxDstSizePtr can be any size. The function will report how many bytes were read or written by modifying *srcSizePtr and *maxDstSizePtr. Note that it may not consume the entire input, in which case it's up to the caller to present remaining input again. The content of dst will be overwritten (up to *maxDstSizePtr) at each function call, so save its content if it matters or change dst.

Returns

: a hint to preferred nb of bytes to use as input for next function call (it's only a hint, to improve latency) or 0 when a frame is completely decoded or an error code, which can be tested using ZBUFF_isError().

Hint : recommended buffer sizes (not compulsory) : ZBUFF_recommendedDInSize / ZBUFF_recommendedDOutSize output : ZBUFF_recommendedDOutSize==128 KB block size is the internal unit, it ensures it's always possible to write a full block when it's decoded. input : ZBUFF_recommendedDInSize==128Kb+3; just follow indications from ZBUFF_decompressContinue() to minimize latency. It should always be <= 128 KB + 3 .

ZBUFFv04_recommendedDInSize()

size_t ZBUFFv04_recommendedDInSize

(

void

)

The below functions provide recommended buffer sizes for Compression or Decompression operations. These sizes are not compulsory, they just tend to offer better latency

ZBUFFv04_recommendedDOutSize()

size_t ZBUFFv04_recommendedDOutSize

(

void

)

ZSTDv04_createDCtx()

ZSTDv04_Dctx * ZSTDv04_createDCtx

(

void

)

ZSTDv04_decompress()

size_t ZSTDv04_decompress	(	void *	dst,
		size_t	maxOriginalSize,
		const void *	src,
		size_t	compressedSize )

ZSTDv04_decompress() : decompress ZSTD frames compliant with v0.4.x format compressedSize : is the exact source size maxOriginalSize : is the size of the 'dst' buffer, which must be already allocated. It must be equal or larger than originalSize, otherwise decompression will fail. return : the number of bytes decompressed into destination buffer (originalSize) or an errorCode if it fails (which can be tested using ZSTDv01_isError())

ZSTDv04_decompressContinue()

size_t ZSTDv04_decompressContinue	(	ZSTDv04_Dctx *	dctx,
		void *	dst,
		size_t	maxDstSize,
		const void *	src,
		size_t	srcSize )

ZSTDv04_decompressDCtx()

size_t ZSTDv04_decompressDCtx	(	ZSTDv04_Dctx *	dctx,
		void *	dst,
		size_t	maxOriginalSize,
		const void *	src,
		size_t	compressedSize )

ZSTDv04_findFrameSizeInfoLegacy()

void ZSTDv04_findFrameSizeInfoLegacy	(	const void *	src,
		size_t	srcSize,
		size_t *	cSize,
		unsigned long long *	dBound )

ZSTDv04_findFrameSizeInfoLegacy() : get the source length and decompressed bound of a ZSTD frame compliant with v0.4.x format srcSize : The size of the 'src' buffer, at least as large as the frame pointed to by 'src' cSize (output parameter) : the number of bytes that would be read to decompress this frame or an error code if it fails (which can be tested using ZSTDv01_isError()) dBound (output parameter) : an upper-bound for the decompressed size of the data in the frame or ZSTD_CONTENTSIZE_ERROR if an error occurs

note : assumes cSize and dBound are not NULL.

ZSTDv04_freeDCtx()

size_t ZSTDv04_freeDCtx

(

ZSTDv04_Dctx *

dctx

)

ZSTDv04_isError()

unsigned ZSTDv04_isError

(

size_t

code

)

ZSTDv04_isError() : tells if the result of ZSTDv04_decompress() is an error

ZSTDv04_nextSrcSizeToDecompress()

size_t ZSTDv04_nextSrcSizeToDecompress

(

ZSTDv04_Dctx *

dctx

)

ZSTDv04_resetDCtx()

size_t ZSTDv04_resetDCtx

(

ZSTDv04_Dctx *

dctx

)