arch/util/lz4.h File Reference

Go to the source code of this file.

Data Structures
struct	LZ4_stream_t_internal
struct	LZ4_streamDecode_t_internal
struct	LZ4_stream_t_internal
struct	LZ4_streamDecode_t_internal
union	LZ4_stream_u
union	LZ4_streamDecode_u
Typedefs
typedef union LZ4_stream_u	LZ4_stream_t
typedef union LZ4_streamDecode_u	LZ4_streamDecode_t
typedef struct LZ4_stream_t_internal	LZ4_stream_t_internal
Functions
LZ4LIB_API int	LZ4_versionNumber (void)
	library version number; useful to check dll version
LZ4LIB_API const char *	LZ4_versionString (void)
	library version string; unseful to check dll version
LZ4LIB_API int	LZ4_compress_default (const char *src, char *dst, int srcSize, int dstCapacity)
LZ4LIB_API int	LZ4_decompress_safe (const char *src, char *dst, int compressedSize, int dstCapacity)
LZ4LIB_API int	LZ4_compressBound (int inputSize)
LZ4LIB_API int	LZ4_compress_fast (const char *src, char *dst, int srcSize, int dstCapacity, int acceleration)
LZ4LIB_API int	LZ4_sizeofState (void)
LZ4LIB_API int	LZ4_compress_fast_extState (void *state, const char *src, char *dst, int srcSize, int dstCapacity, int acceleration)
LZ4LIB_API int	LZ4_compress_destSize (const char *src, char *dst, int *srcSizePtr, int targetDstSize)
LZ4LIB_API int	LZ4_decompress_fast (const char *src, char *dst, int originalSize)
LZ4LIB_API int	LZ4_decompress_safe_partial (const char *src, char *dst, int srcSize, int targetOutputSize, int dstCapacity)
LZ4LIB_API LZ4_stream_t *	LZ4_createStream (void)
LZ4LIB_API int	LZ4_freeStream (LZ4_stream_t *streamPtr)
LZ4LIB_API void	LZ4_resetStream (LZ4_stream_t *streamPtr)
LZ4LIB_API int	LZ4_loadDict (LZ4_stream_t *streamPtr, const char *dictionary, int dictSize)
LZ4LIB_API int	LZ4_compress_fast_continue (LZ4_stream_t *streamPtr, const char *src, char *dst, int srcSize, int dstCapacity, int acceleration)
LZ4LIB_API int	LZ4_saveDict (LZ4_stream_t *streamPtr, char *safeBuffer, int maxDictSize)
LZ4LIB_API LZ4_streamDecode_t *	LZ4_createStreamDecode (void)
LZ4LIB_API int	LZ4_freeStreamDecode (LZ4_streamDecode_t *LZ4_stream)
LZ4LIB_API int	LZ4_setStreamDecode (LZ4_streamDecode_t *LZ4_streamDecode, const char *dictionary, int dictSize)
LZ4LIB_API int	LZ4_decoderRingBufferSize (int maxBlockSize)
LZ4LIB_API int	LZ4_decompress_safe_continue (LZ4_streamDecode_t *LZ4_streamDecode, const char *src, char *dst, int srcSize, int dstCapacity)
LZ4LIB_API int	LZ4_decompress_fast_continue (LZ4_streamDecode_t *LZ4_streamDecode, const char *src, char *dst, int originalSize)
LZ4LIB_API int	LZ4_decompress_safe_usingDict (const char *src, char *dst, int srcSize, int dstCapcity, const char *dictStart, int dictSize)
LZ4LIB_API int	LZ4_decompress_fast_usingDict (const char *src, char *dst, int originalSize, const char *dictStart, int dictSize)
LZ4LIB_API void	LZ4_resetStream_fast (LZ4_stream_t *streamPtr)
LZ4LIB_API int	LZ4_compress_fast_extState_fastReset (void *state, const char *src, char *dst, int srcSize, int dstCapacity, int acceleration)
	LZ4_compress_fast_extState_fastReset() : A variant of LZ4_compress_fast_extState().
LZ4LIB_API void	LZ4_attach_dictionary (LZ4_stream_t *working_stream, const LZ4_stream_t *dictionary_stream)
	LZ4_DEPRECATED ("use LZ4_compress_default() instead") LZ4LIB_API int LZ4_compress(const char *source
	LZ4_DEPRECATED ("use LZ4_compress_fast_extState() instead") LZ4LIB_API int LZ4_compress_withState(void *state
	LZ4_DEPRECATED ("use LZ4_compress_fast_continue() instead") LZ4LIB_API int LZ4_compress_continue(LZ4_stream_t *LZ4_streamPtr
	LZ4_DEPRECATED ("use LZ4_decompress_fast() instead") LZ4LIB_API int LZ4_uncompress(const char *source
	LZ4_DEPRECATED ("use LZ4_decompress_safe() instead") LZ4LIB_API int LZ4_uncompress_unknownOutputSize(const char *source
	LZ4_DEPRECATED ("Use LZ4_createStream() instead") LZ4LIB_API void *LZ4_create(char *inputBuffer)
	LZ4_DEPRECATED ("Use LZ4_resetStream() instead") LZ4LIB_API int LZ4_resetStreamState(void *state
	LZ4_DEPRECATED ("Use LZ4_saveDict() instead") LZ4LIB_API char *LZ4_slideInputBuffer(void *state)
	LZ4_DEPRECATED ("use LZ4_decompress_safe_usingDict() instead") LZ4LIB_API int LZ4_decompress_safe_withPrefix64k(const char *src
	LZ4_DEPRECATED ("use LZ4_decompress_fast_usingDict() instead") LZ4LIB_API int LZ4_decompress_fast_withPrefix64k(const char *src
Variables
char *	dest
char int	sourceSize
char int int	maxOutputSize
const char *	source
const char char int	inputSize
char int	outputSize
char int	isize
char *	inputBuffer
char *	dst
char int	compressedSize
char int int	maxDstSize
char int	originalSize

---

Typedef Documentation

typedef union LZ4_stream_u LZ4_stream_t

Definition at line 258 of file lz4.h.

typedef union LZ4_streamDecode_u LZ4_streamDecode_t

Definition at line 320 of file lz4.h.

typedef struct LZ4_stream_t_internal LZ4_stream_t_internal [read]

Definition at line 496 of file lz4.h.

---

Function Documentation

LZ4LIB_API int LZ4_versionNumber

(

void

)

library version number; useful to check dll version

Definition at line 491 of file lz4.c.

LZ4LIB_API const char* LZ4_versionString

(

void

)

library version string; unseful to check dll version

Definition at line 492 of file lz4.c.

LZ4LIB_API int LZ4_compress_default	(	const char *	src,
		char *	dst,
		int	srcSize,
		int	dstCapacity
	)

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. Note : as a consequence, 'dst' content is not valid. Note 2 : This function is protected against buffer overflow scenarios (never writes outside 'dst' buffer, nor read outside 'source' buffer). 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

Definition at line 1097 of file lz4.c.

References LZ4_compress_fast().

Referenced by compressLz4(), LZ4_compress(), and LZ4_compress_limitedOutput().

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LZ4LIB_API int LZ4_decompress_safe	(	const char *	src,
		char *	dst,
		int	compressedSize,
		int	dstCapacity
	)

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. 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. This function is protected against malicious data packets.

Definition at line 1651 of file lz4.c.

References decode_full_block, endOnInputSize, LZ4_decompress_generic(), and noDict.

Referenced by decompressLz4(), LZ4_decompress_safe_continue(), LZ4_decompress_safe_usingDict(), and LZ4_uncompress_unknownOutputSize().

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LZ4LIB_API int LZ4_compressBound

(

int

inputSize

)

LZ4_compressBound() : 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)

Definition at line 493 of file lz4.c.

Referenced by compressLz4(), CompressPersistentMsg(), LZ4_compress(), LZ4_compress_continue(), LZ4_compress_destSize_extState(), LZ4_compress_fast_extState(), LZ4_compress_fast_extState_fastReset(), and LZ4_compress_withState().

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LZ4LIB_API int LZ4_compress_fast	(	const char *	src,
		char *	dst,
		int	srcSize,
		int	dstCapacity,
		int	acceleration
	)

LZ4_compress_fast() : 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).

Definition at line 1078 of file lz4.c.

References LZ4_compress_fast_extState().

Referenced by LZ4_compress_default().

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LZ4LIB_API int LZ4_sizeofState

(

void

)

LZ4_compress_fast_extState() : Same compression function, just using an externally allocated memory space to store compression 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.

Definition at line 494 of file lz4.c.

LZ4LIB_API int LZ4_compress_fast_extState	(	void *	state,
		const char *	src,
		char *	dst,
		int	srcSize,
		int	dstCapacity,
		int	acceleration
	)

Definition at line 1010 of file lz4.c.

References byPtr, byU16, byU32, limitedOutput, LZ4_compress_generic(), LZ4_compressBound(), LZ4_resetStream(), noDict, noDictIssue, and notLimited.

Referenced by LZ4_compress_destSize_extState(), LZ4_compress_fast(), LZ4_compress_limitedOutput_withState(), and LZ4_compress_withState().

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LZ4LIB_API int LZ4_compress_destSize	(	const char *	src,
		char *	dst,
		int *	srcSizePtr,
		int	targetDstSize
	)

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.

Returns:

: Nb bytes written into 'dst' (necessarily <= targetDestSize) or 0 if compression fails.

Definition at line 1136 of file lz4.c.

References LZ4_compress_destSize_extState().

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LZ4LIB_API int LZ4_decompress_fast	(	const char *	src,
		char *	dst,
		int	originalSize
	)

LZ4_decompress_fast() : **unsafe!** This function used to be a bit faster than LZ4_decompress_safe(), though situation has changed in recent versions, and now `LZ4_decompress_safe()` can be as fast and sometimes faster than `LZ4_decompress_fast()`. Moreover, LZ4_decompress_fast() is not protected vs malformed input, as it doesn't perform full validation of compressed data. As a consequence, this function is no longer recommended, and may be deprecated in future versions. It's only remaining specificity is that it can decompress data without knowing its compressed size.

originalSize : is the uncompressed size to regenerate. `dst` must be already allocated, its size must be >= 'originalSize' bytes.

Returns:

: number of bytes read from source buffer (== compressed size). If the source stream is detected malformed, the function stops decoding and returns a negative result. note : This function requires uncompressed originalSize to be known in advance. The function never writes past the output buffer. However, since it doesn't know its 'src' size, it may read past the intended input. Also, because match offsets are not validated during decoding, reads from 'src' may underflow. Use this function in trusted environment **only**.

Definition at line 1668 of file lz4.c.

References decode_full_block, endOnOutputSize, LZ4_decompress_generic(), and withPrefix64k.

Referenced by LZ4_decompress_fast_continue(), LZ4_decompress_fast_usingDict(), LZ4_decompress_fast_withPrefix64k(), and LZ4_uncompress().

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LZ4LIB_API int LZ4_decompress_safe_partial	(	const char *	src,
		char *	dst,
		int	srcSize,
		int	targetOutputSize,
		int	dstCapacity
	)

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.

Returns:

: the number of bytes decoded in `dst` (necessarily <= dstCapacity) If source stream is detected malformed, function returns a negative result.

Note :

Returns:

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.

Definition at line 1659 of file lz4.c.

References endOnInputSize, LZ4_decompress_generic(), noDict, and partial_decode.

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LZ4LIB_API LZ4_stream_t* LZ4_createStream

(

void

)

LZ4_createStream() and LZ4_freeStream() : LZ4_createStream() will allocate and initialize an `LZ4_stream_t` structure. LZ4_freeStream() releases its memory.

Definition at line 1160 of file lz4.c.

References LZ4_resetStream().

Referenced by LZ4_create().

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LZ4LIB_API int LZ4_freeStream

(

LZ4_stream_t *

streamPtr

)

Definition at line 1180 of file lz4.c.

LZ4LIB_API void LZ4_resetStream

(

LZ4_stream_t *

streamPtr

)

LZ4_resetStream() : An LZ4_stream_t structure can be allocated once and re-used multiple times. Use this function to start compressing a new stream.

Definition at line 1170 of file lz4.c.

Referenced by LZ4_compress_destSize_extState(), LZ4_compress_fast_extState(), LZ4_compress_fast_force(), LZ4_createStream(), LZ4_loadDict(), and LZ4_resetStreamState().

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LZ4LIB_API int LZ4_loadDict	(	LZ4_stream_t *	streamPtr,
		const char *	dictionary,
		int	dictSize
	)

LZ4_loadDict() : Use this function to load a static dictionary into LZ4_stream_t. Any previous data will be forgotten, only 'dictionary' will remain in memory. Loading a size of 0 is allowed, and is the same as reset.

Returns:

: dictionary size, in bytes (necessarily <= 64 KB)

Definition at line 1190 of file lz4.c.

References byU32, LZ4_stream_t_internal::currentOffset, LZ4_stream_t_internal::dictionary, LZ4_stream_t_internal::dictSize, LZ4_stream_t_internal::hashTable, LZ4_stream_u::internal_donotuse, LZ4_putPosition(), LZ4_resetStream(), p, and LZ4_stream_t_internal::tableType.

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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
	)

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.

Returns:

: 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. It's not possible to append blocks together and expect a single invocation of LZ4_decompress_*() to decompress them together. Each block must be decompressed separately, calling LZ4_decompress_*() with associated metadata.

Note 2 : The previous 64KB 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 invalid, it can only be reset or freed.

Definition at line 1268 of file lz4.c.

References byU32, LZ4_stream_t_internal::currentOffset, LZ4_stream_t_internal::dictCtx, LZ4_stream_t_internal::dictionary, LZ4_stream_t_internal::dictSize, dictSmall, LZ4_stream_t_internal::initCheck, LZ4_stream_u::internal_donotuse, limitedOutput, LZ4_compress_generic(), LZ4_renormDictT(), noDictIssue, usingDictCtx, usingExtDict, and withPrefix64k.

Referenced by LZ4_compress_continue(), and LZ4_compress_limitedOutput_continue().

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LZ4LIB_API int LZ4_saveDict	(	LZ4_stream_t *	LZ4_dict,
		char *	safeBuffer,
		int	dictSize
	)

LZ4_saveDict() : If last 64KB 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.

Returns:

: saved dictionary size in bytes (necessarily <= maxDictSize), or 0 if error.

LZ4_saveDict() : If previously compressed data block is not guaranteed to remain available at its memory location, save it into a safer place (char* safeBuffer). Note : you don't need to call LZ4_loadDict() afterwards, dictionary is immediately usable, you can therefore call LZ4_compress_fast_continue(). Return : saved dictionary size in bytes (necessarily <= dictSize), or 0 if error.

Definition at line 1368 of file lz4.c.

References LZ4_stream_t_internal::dictionary, LZ4_stream_t_internal::dictSize, and LZ4_stream_u::internal_donotuse.

LZ4LIB_API LZ4_streamDecode_t* LZ4_createStreamDecode

(

void

)

LZ4_createStreamDecode() and LZ4_freeStreamDecode() : creation / destruction of streaming decompression tracking context. A tracking context can be re-used multiple times.

Definition at line 1745 of file lz4.c.

LZ4LIB_API int LZ4_freeStreamDecode

(

LZ4_streamDecode_t *

LZ4_stream

)

Definition at line 1751 of file lz4.c.

LZ4LIB_API int LZ4_setStreamDecode	(	LZ4_streamDecode_t *	LZ4_streamDecode,
		const char *	dictionary,
		int	dictSize
	)

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.

Returns:

: 1 if OK, 0 if error

LZ4_setStreamDecode() : Use this function to instruct where to find the dictionary. This function is not necessary if previous data is still available where it was decoded. Loading a size of 0 is allowed (same effect as no dictionary).

Returns:

: 1 if OK, 0 if error

Definition at line 1764 of file lz4.c.

References LZ4_streamDecode_t_internal::extDictSize, LZ4_streamDecode_t_internal::externalDict, LZ4_streamDecode_u::internal_donotuse, LZ4_streamDecode_t_internal::prefixEnd, LZ4_streamDecode_t_internal::prefixSize, and size_t.

LZ4LIB_API int LZ4_decoderRingBufferSize

(

int

maxBlockSize

)

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.

Returns:

: minimum ring buffer size, or 0 if there is an error (invalid maxBlockSize).

LZ4_decoderRingBufferSize() : when setting a ring buffer for streaming decompression (optional scenario), provides the minimum size of this ring buffer to be compatible with any source respecting maxBlockSize condition. Note : in a ring buffer scenario, blocks are presumed decompressed next to each other. When not enough space remains for next block (remainingSize < maxBlockSize), decoding resumes from beginning of ring buffer.

Returns:

: minimum ring buffer size, or 0 if there is an error (invalid maxBlockSize).

Definition at line 1785 of file lz4.c.

LZ4LIB_API int LZ4_decompress_safe_continue	(	LZ4_streamDecode_t *	LZ4_streamDecode,
		const char *	src,
		char *	dst,
		int	srcSize,
		int	dstCapacity
	)

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 64KB of previously decoded data *must* remain available and unmodified at the memory position where they were decoded. If less than 64KB 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 64KB 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.

Definition at line 1801 of file lz4.c.

References assert, LZ4_streamDecode_t_internal::extDictSize, LZ4_streamDecode_t_internal::externalDict, LZ4_streamDecode_u::internal_donotuse, LZ4_decompress_safe(), LZ4_decompress_safe_doubleDict(), LZ4_decompress_safe_forceExtDict(), LZ4_decompress_safe_withPrefix64k(), LZ4_decompress_safe_withSmallPrefix(), LZ4_streamDecode_t_internal::prefixEnd, and LZ4_streamDecode_t_internal::prefixSize.

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LZ4LIB_API int LZ4_decompress_fast_continue	(	LZ4_streamDecode_t *	LZ4_streamDecode,
		const char *	src,
		char *	dst,
		int	originalSize
	)

Definition at line 1841 of file lz4.c.

References assert, LZ4_streamDecode_t_internal::extDictSize, LZ4_streamDecode_t_internal::externalDict, LZ4_streamDecode_u::internal_donotuse, LZ4_decompress_fast(), LZ4_decompress_fast_doubleDict(), LZ4_decompress_fast_extDict(), LZ4_streamDecode_t_internal::prefixEnd, and LZ4_streamDecode_t_internal::prefixSize.

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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
	)

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 next decompression.

Definition at line 1882 of file lz4.c.

References LZ4_decompress_safe(), LZ4_decompress_safe_forceExtDict(), LZ4_decompress_safe_withPrefix64k(), and LZ4_decompress_safe_withSmallPrefix().

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LZ4LIB_API int LZ4_decompress_fast_usingDict	(	const char *	src,
		char *	dst,
		int	originalSize,
		const char *	dictStart,
		int	dictSize
	)

Definition at line 1894 of file lz4.c.

References LZ4_decompress_fast(), and LZ4_decompress_fast_extDict().

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LZ4LIB_API void LZ4_resetStream_fast

(

LZ4_stream_t *

streamPtr

)

LZ4_resetStream_fast() : Use this, like LZ4_resetStream(), to prepare a context for a new chain of calls to a streaming API (e.g., LZ4_compress_fast_continue()).

Note: Using this in advance of a non- streaming-compression function is redundant, and potentially bad for performance, since they all perform their own custom reset internally.

Differences from LZ4_resetStream(): When an LZ4_stream_t is known to be in a internally coherent state, it can often be prepared for a new compression with almost no work, only sometimes falling back to the full, expensive reset that is always required when the stream is in an indeterminate state (i.e., the reset performed by LZ4_resetStream()).

LZ4_streams are guaranteed to be in a valid state when:

• returned from LZ4_createStream()
• reset by LZ4_resetStream()
• memset(stream, 0, sizeof(LZ4_stream_t)), though this is discouraged
• the stream was in a valid state and was reset by LZ4_resetStream_fast()
• the stream was in a valid state and was then used in any compression call that returned success
• the stream was in an indeterminate state and was used in a compression call that fully reset the state (e.g., LZ4_compress_fast_extState()) and that returned success

When a stream isn't known to be in a valid state, it is not safe to pass to any fastReset or streaming function. It must first be cleansed by the full LZ4_resetStream().

Definition at line 1176 of file lz4.c.

References byU32, LZ4_stream_u::internal_donotuse, and LZ4_prepareTable().

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LZ4LIB_API int LZ4_compress_fast_extState_fastReset	(	void *	state,
		const char *	src,
		char *	dst,
		int	srcSize,
		int	dstCapacity,
		int	acceleration
	)

LZ4_compress_fast_extState_fastReset() : A variant of LZ4_compress_fast_extState().

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().

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 comment in lz4.h on LZ4_resetStream_fast() for a definition of "correctly initialized").

Definition at line 1041 of file lz4.c.

References byPtr, byU16, byU32, LZ4_stream_t_internal::currentOffset, dictSmall, limitedOutput, LZ4_compress_generic(), LZ4_compressBound(), LZ4_prepareTable(), noDict, noDictIssue, and notLimited.

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LZ4LIB_API void LZ4_attach_dictionary	(	LZ4_stream_t *	working_stream,
		const LZ4_stream_t *	dictionary_stream
	)

LZ4_attach_dictionary() : This is an experimental API that allows for the 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 dictionary stream pointer 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.

Definition at line 1232 of file lz4.c.

References LZ4_stream_t_internal::currentOffset, LZ4_stream_t_internal::dictCtx, and LZ4_stream_u::internal_donotuse.

LZ4_DEPRECATED

(

"use LZ4_compress_default() instead"

)

const

LZ4_DEPRECATED

(

"use LZ4_compress_fast_extState() instead"

)

LZ4_DEPRECATED

(

"use LZ4_compress_fast_continue() instead"

)

LZ4_DEPRECATED

(

"use LZ4_decompress_fast() instead"

)

const

LZ4_DEPRECATED

(

"use LZ4_decompress_safe() instead"

)

const

LZ4_DEPRECATED

(

"Use LZ4_createStream() instead"

)

LZ4_DEPRECATED

(

"Use LZ4_resetStream() instead"

)

LZ4_DEPRECATED

(

"Use LZ4_saveDict() instead"

)

LZ4_DEPRECATED

(

"use LZ4_decompress_safe_usingDict() instead"

)

const

LZ4_DEPRECATED

(

"use LZ4_decompress_fast_usingDict() instead"

)

const

---

Variable Documentation

char* dest

Definition at line 597 of file lz4.h.

char int sourceSize

Definition at line 597 of file lz4.h.

char int int maxOutputSize

Definition at line 598 of file lz4.h.

const char* source

Definition at line 599 of file lz4.h.

const char char int inputSize

Definition at line 599 of file lz4.h.

char int outputSize

Definition at line 605 of file lz4.h.

char int isize

Definition at line 606 of file lz4.h.

char* inputBuffer

Definition at line 619 of file lz4.h.

char * dst

Definition at line 623 of file lz4.h.

Referenced by AMPI_Alltoall_long(), AMPI_Alltoall_medium(), AMPI_Alltoall_short(), AMPI_API_IMPL(), check_dst_limits_calc_pos_1(), CkDDT_SetName(), main(), and PUPbytes().

char int compressedSize

Definition at line 623 of file lz4.h.

char int int maxDstSize

Definition at line 623 of file lz4.h.

char int originalSize

Definition at line 624 of file lz4.h.

Referenced by persistentDecompressHandler().