lzw.c File Reference

LZW decoding routines. More...

#include "libavutil/attributes.h"
#include "bytestream.h"
#include "lzw.h"
#include "libavutil/mem.h"

Go to the source code of this file.

Data Structures
struct	LZWState

Macros
#define	LZW_MAXBITS   12
#define	LZW_SIZTABLE   (1<<LZW_MAXBITS)

Functions
static int	lzw_get_code (struct LZWState *s)
int	ff_lzw_decode_tail (LZWState *p)
av_cold void	ff_lzw_decode_open (LZWState **p)
av_cold void	ff_lzw_decode_close (LZWState **p)
int	ff_lzw_decode_init (LZWState *p, int csize, const uint8_t *buf, int buf_size, int mode)
	Initialize LZW decoder. More...
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. More...

Variables
static const uint16_t	mask [17]

Detailed Description

LZW decoding routines.

Author

Fabrice Bellard

modified for use in TIFF by Konstantin Shishkov

Definition in file lzw.c.

Macro Definition Documentation

LZW_MAXBITS

#define LZW_MAXBITS   12

Definition at line 35 of file lzw.c.

LZW_SIZTABLE

#define LZW_SIZTABLE   (1<<LZW_MAXBITS)

Definition at line 36 of file lzw.c.

Function Documentation

lzw_get_code()

static int lzw_get_code ( struct LZWState *  s )

static

Definition at line 70 of file lzw.c.

Referenced by ff_lzw_decode().

ff_lzw_decode_tail()

int ff_lzw_decode_tail

(

LZWState *

p

)

Definition at line 99 of file lzw.c.

Referenced by gif_read_image().

ff_lzw_decode_open()

av_cold 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()

av_cold 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().

Variable Documentation

mask

const uint16_t mask[17]

static

Initial value:

=
{
    0x0000, 0x0001, 0x0003, 0x0007,
    0x000F, 0x001F, 0x003F, 0x007F,
    0x00FF, 0x01FF, 0x03FF, 0x07FF,
    0x0FFF, 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF
}

Definition at line 38 of file lzw.c.

Referenced by ff_lzw_decode(), and ff_lzw_decode_init().