lzw.h File Reference

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Detailed Description

LZW decoding routines.

Author:

Fabrice Bellard Modified for use in TIFF by Konstantin Shishkov

Definition in file lzw.h.

Go to the source code of this file.

Typedefs
typedef void	LZWState
Enumerations
enum	FF_LZW_MODES { FF_LZW_GIF, FF_LZW_TIFF }
Functions
void	ff_lzw_decode_open (LZWState **p)
void	ff_lzw_decode_close (LZWState **p)
int	ff_lzw_decode_init (LZWState *s, int csize, uint8_t *buf, int buf_size, int mode)
	Initialize LZW decoder.
int	ff_lzw_decode (LZWState *s, uint8_t *buf, int len)
	Decode given number of bytes NOTE: the algorithm here is inspired from the LZW GIF decoder written by Steven A.
uint8_t *	ff_lzw_cur_ptr (LZWState *lzw)
void	ff_lzw_decode_tail (LZWState *lzw)
void	ff_lzw_encode_init (struct LZWEncodeState *s, uint8_t *outbuf, int outsize, int maxbits)
	Initialize LZW encoder.
int	ff_lzw_encode (struct LZWEncodeState *s, const uint8_t *inbuf, int insize)
	LZW main compress function.
int	ff_lzw_encode_flush (struct LZWEncodeState *s)
	Write end code and flush bitstream.
Variables
const int	ff_lzw_encode_state_size

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Typedef Documentation

typedef void LZWState

Definition at line 41 of file lzw.h.

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Enumeration Type Documentation

enum FF_LZW_MODES

Enumerator:

FF_LZW_GIF
FF_LZW_TIFF

Definition at line 35 of file lzw.h.

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Function Documentation

void ff_lzw_decode_open

(

LZWState **

p

)

Definition at line 112 of file lzw.c.

Referenced by gif_decode_init(), and tiff_init().

void ff_lzw_decode_close

(

LZWState **

p

)

Definition at line 117 of file lzw.c.

Referenced by gif_decode_close(), and tiff_end().

int ff_lzw_decode_init	(	LZWState *	p,
		int	csize,
		uint8_t *	buf,
		int	buf_size,
		int	mode
	)

Initialize LZW decoder.

Parameters:

	s	LZW context
	csize	initial code size in bits
	buf	input data
	buf_size	input data size
	mode	decoder working mode - either GIF or TIFF

Definition at line 130 of file lzw.c.

Referenced by gif_read_image(), and tiff_unpack_strip().

int ff_lzw_decode	(	LZWState *	p,
		uint8_t *	buf,
		int	len
	)

Decode given number of bytes NOTE: the algorithm here is inspired from the LZW GIF decoder written by Steven A.

Bennett in 1987.

Parameters:

	s	LZW context
	buf	output buffer
	len	number of bytes to decode

Returns:

number of bytes decoded

Definition at line 169 of file lzw.c.

Referenced by gif_read_image(), and tiff_unpack_strip().

uint8_t* ff_lzw_cur_ptr

(

LZWState *

lzw

)

Definition at line 94 of file lzw.c.

Referenced by gif_read_image().

void ff_lzw_decode_tail

(

LZWState *

lzw

)

Definition at line 99 of file lzw.c.

Referenced by gif_read_image().

void ff_lzw_encode_init	(	LZWEncodeState *	s,
		uint8_t *	outbuf,
		int	outsize,
		int	maxbits
	)

Initialize LZW encoder.

Please set s->clear_code, s->end_code and s->maxbits before run.

Parameters:

	s	LZW state
	outbuf	Output buffer
	outsize	Size of output buffer
	maxbits	Maximum length of code

Definition at line 199 of file lzwenc.c.

int ff_lzw_encode	(	LZWEncodeState *	s,
		const uint8_t *	inbuf,
		int	insize
	)

LZW main compress function.

Parameters:

	s	LZW state
	inbuf	Input buffer
	insize	Size of input buffer

Returns:

Number of bytes written or -1 on error

Definition at line 220 of file lzwenc.c.

Referenced by encode_strip().

int ff_lzw_encode_flush

(

LZWEncodeState *

s

)

Write end code and flush bitstream.

Parameters:

s

LZW state

Returns:

Number of bytes written or -1 on error

Definition at line 253 of file lzwenc.c.

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Variable Documentation

const int ff_lzw_encode_state_size

Definition at line 64 of file lzwenc.c.