lz4_dec.c File Reference

Data Structures
struct	lz4dec_faststate_t
	Fast-access state of the LZ4 algorithm (streaming version). More...
struct	lz4dec_state_t
	State of the LZ4 algorithm (streaming version). More...

Macros
#define	MIN_MATCH_SIZE   4
	Minimum match size for LZ4.
#define	LITERALS_RUN_LEN   15
	Maximum run length for literals in LZ4.
#define	MATCH_RUN_LEN   15
	Maximum run length for matches in LZ4.
#define	LZ4ULTRA_DECOMPRESSOR_BUILD_LEN(__len)
	Decode multi-byte length.

Functions
int	decompress_lz4_full_inplace (const unsigned char *pInBlock, size_t nBlockSize, unsigned char *pOutData, size_t nBlockMaxSize)
void	decompress_lz4_init (void *state, int fd, int winsize)
	Initialize the LZ4 decompressor state.
void	decompress_lz4_reset (void *state)
	Reset the LZ4 decompressor state.
ssize_t	decompress_lz4_read (void *state, void *buf, size_t len)
	Read decompressed data from the LZ4 stream.

Detailed Description

Author

Giovanni Bajo giova.nosp@m.nnib.nosp@m.ajo@g.nosp@m.mail.nosp@m..com

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Data Structure Documentation

lz4dec_faststate_t

struct lz4dec_faststate_t

Fast-access state of the LZ4 algorithm (streaming version).

See the LZ4 block format for a better understanding of the fields.

Data Fields
uint8_t	token	Current token.
int	lit_len	Number of literals to copy.
int	match_len	Number of bytes to copy from the ring buffer.
int	match_off	Offset in the ring buffer to copy from.
int	fsm_state	Current state of the streaming state machine.

lz4dec_state_t

struct lz4dec_state_t

State of the LZ4 algorithm (streaming version).

Data Fields
uint8_t	buf[128]	File buffer.
int	fd	File descriptor to read from.
int	buf_idx	Current index in the file buffer.
int	buf_size	Size of the file buffer.
bool	eof	True if we reached the end of the file.
lz4dec_faststate_t	st	Fast-access state.
decompress_ringbuf_t	ringbuf	Ring buffer.

Macro Definition Documentation

LZ4ULTRA_DECOMPRESSOR_BUILD_LEN

#define LZ4ULTRA_DECOMPRESSOR_BUILD_LEN

(

__len

)

Value:

   { \
   unsigned int byte; \
   do { \
      if (unlikely(pInBlock >= pInBlockEnd)) return -1; \
      if (dma_race) wait_dma(pInBlock+1); \
      byte = (unsigned int)*pInBlock++; \
      __len += byte; \
   } while (unlikely(byte == 255)); \
}

Decode multi-byte length.

Function Documentation

decompress_lz4_full_inplace()

int decompress_lz4_full_inplace	(	const unsigned char *	pInBlock,
		size_t	nBlockSize,
		unsigned char *	pOutData,
		size_t	nBlockMaxSize
	)

Decompress one data block

Parameters

pInBlock	pointer to compressed data
nBlockSize	size of compressed data, in bytes
pOutData	pointer to output decompression buffer (previously decompressed bytes + room for decompressing this block)
nBlockMaxSize	total size of output decompression buffer, in bytes

Returns

size of decompressed data in bytes, or -1 for error

decompress_lz4_init()

void decompress_lz4_init	(	void *	state,
		int	fd,
		int	winsize
	)

Initialize the LZ4 decompressor state.

Parameters

state	Pointer to the decompressor state buffer.
fd	File descriptor to read compressed data from.
winsize	Window size for the decompressor.

decompress_lz4_reset()

void decompress_lz4_reset

(

void *

state

)

Reset the LZ4 decompressor state.

Parameters

state

Pointer to the decompressor state buffer.

decompress_lz4_read()

ssize_t decompress_lz4_read	(	void *	state,
		void *	buf,
		size_t	len
	)

Read decompressed data from the LZ4 stream.

Parameters

state	Pointer to the decompressor state buffer.
buf	Buffer to store decompressed data.
len	Number of bytes to read.

Returns

Number of bytes read, or -1 on error.