lzw.h File Reference

LZW decoding routines. More...

#include <stdint.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, const uint8_t *buf, int buf_size, int mode)
	Initialize LZW decoder. More...
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. More...
int	ff_lzw_decode_tail (LZWState *lzw)
void	ff_lzw_encode_init (struct LZWEncodeState *s, uint8_t *outbuf, int outsize, int maxbits, enum FF_LZW_MODES mode, int little_endian)
	Initialize LZW encoder. More...
int	ff_lzw_encode (struct LZWEncodeState *s, const uint8_t *inbuf, int insize)
	LZW main compress function. More...
int	ff_lzw_encode_flush (struct LZWEncodeState *s)
	Write end code and flush bitstream. More...

Variables
const int	ff_lzw_encode_state_size

Detailed Description

LZW decoding routines.

Author

Fabrice Bellard

modified for use in TIFF by Konstantin Shishkov

Definition in file lzw.h.

Typedef Documentation

LZWState

typedef void LZWState

Definition at line 43 of file lzw.h.

Enumeration Type Documentation

FF_LZW_MODES

enum FF_LZW_MODES

Enumerator
FF_LZW_GIF
FF_LZW_TIFF

Definition at line 37 of file lzw.h.

Function Documentation

ff_lzw_decode_open()

void ff_lzw_decode_open

(

LZWState **

p

)

Definition at line 113 of file lzw.c.

Referenced by gif_decode_init(), and tiff_init().

ff_lzw_decode_close()

void ff_lzw_decode_close

(

LZWState **

p

)

Definition at line 118 of file lzw.c.

Referenced by gif_decode_close(), and tiff_end().

ff_lzw_decode_init()

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

Initialize LZW decoder.

Parameters

p	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 131 of file lzw.c.

Referenced by gif_read_image(), and tiff_unpack_strip().

ff_lzw_decode()

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

p	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().

ff_lzw_decode_tail()

int ff_lzw_decode_tail

(

LZWState *

lzw

)

Definition at line 99 of file lzw.c.

Referenced by gif_read_image().

ff_lzw_encode_init()

void ff_lzw_encode_init	(	LZWEncodeState *	s,
		uint8_t *	outbuf,
		int	outsize,
		int	maxbits,
		enum FF_LZW_MODES	mode,
		int	little_endian
	)

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 206 of file lzwenc.c.

Referenced by encode_frame().

ff_lzw_encode()

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 230 of file lzwenc.c.

Referenced by encode_strip().

ff_lzw_encode_flush()

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 263 of file lzwenc.c.

Referenced by encode_frame().

Variable Documentation

ff_lzw_encode_state_size

const int ff_lzw_encode_state_size

Definition at line 68 of file lzwenc.c.

Referenced by encode_frame(), and gif_encode_init().