libavutil/lzo.c File Reference

#include "avutil.h"
#include "common.h"
#include <string.h>
#include "lzo.h"

Go to the source code of this file.

Data Structures
struct	LZOContext
Defines
#define	OUTBUF_PADDED   1
	Avoid e.g. MPlayers fast_memcpy, it slows things down here.
#define	INBUF_PADDED   1
	Define if we may read up to 8 bytes beyond the input buffer.
#define	GETB(c)   (*(c).in++)
#define	BUILTIN_MEMCPY
#define	COPY2(d, s)   memcpy(d, s, 2);
#define	COPY4(d, s)   memcpy(d, s, 4);
Functions
static int	get_byte (LZOContext *c)
	Reads one byte from the input buffer, avoiding an overrun.
static int	get_len (LZOContext *c, int x, int mask)
	Decodes a length value in the coding used by lzo.
static void	copy (LZOContext *c, int cnt)
	Copies bytes from input to output buffer with checking.
static void	memcpy_backptr (uint8_t *dst, int back, int cnt)
static void	copy_backptr (LZOContext *c, int back, int cnt)
	Copies previously decoded bytes to current position.
void	av_memcpy_backptr (uint8_t *dst, int back, int cnt)
	deliberately overlapping memcpy implementation
int	av_lzo1x_decode (void *out, int *outlen, const void *in, int *inlen)
	Decodes LZO 1x compressed data.

---

Define Documentation

#define BUILTIN_MEMCPY

Definition at line 72 of file lzo.c.

#define COPY2	(	d,
		s		)	memcpy(d, s, 2);

Definition at line 77 of file lzo.c.

Referenced by memcpy_backptr().

#define COPY4	(	d,
		s		)	memcpy(d, s, 4);

Definition at line 78 of file lzo.c.

Referenced by copy().

#define GETB

(

c

)

(*(c).in++)

Definition at line 51 of file lzo.c.

Referenced by av_lzo1x_decode().

#define INBUF_PADDED   1

Define if we may read up to 8 bytes beyond the input buffer.

Definition at line 32 of file lzo.c.

#define OUTBUF_PADDED   1

Avoid e.g. MPlayers fast_memcpy, it slows things down here.

Define if we may write up to 12 bytes beyond the output buffer.

Definition at line 30 of file lzo.c.

---

Function Documentation

int av_lzo1x_decode	(	void *	out,
		int *	outlen,
		const void *	in,
		int *	inlen
	)

Decodes LZO 1x compressed data.

Parameters:

	out	output buffer
	outlen	size of output buffer, number of bytes left are returned here
	in	input buffer
	inlen	size of input buffer, number of bytes left are returned here

Returns:

0 on success, otherwise a combination of the error flags above

Make sure all buffers are appropriately padded, in must provide AV_LZO_INPUT_PADDING, out must provide AV_LZO_OUTPUT_PADDING additional bytes.

Definition at line 174 of file lzo.c.

Referenced by decode_frame(), and matroska_decode_buffer().

void av_memcpy_backptr	(	uint8_t *	dst,
		int	back,
		int	cnt
	)

deliberately overlapping memcpy implementation

Parameters:

	dst	destination buffer; must be padded with 12 additional bytes
	back	how many bytes back we start (the initial size of the overlapping window)
	cnt	number of bytes to copy, must be >= 0

cnt > back is valid, this will copy the bytes we just copied, thus creating a repeating pattern with a period length of back.

Definition at line 170 of file lzo.c.

Referenced by mszh_decomp(), synth_block_fcb_acb(), unpack(), and xan_unpack().

static void copy	(	LZOContext *	c,
		int	cnt
	)			[inline, static]

Copies bytes from input to output buffer with checking.

Parameters:

cnt

number of bytes to copy, must be >= 0

Definition at line 88 of file lzo.c.

Referenced by av_lzo1x_decode(), qpeg_decode_intra(), and roq_decode_frame().

static void copy_backptr	(	LZOContext *	c,
		int	back,
		int	cnt
	)			[inline, static]

Copies previously decoded bytes to current position.

Parameters:

	back	how many bytes back we start
	cnt	number of bytes to copy, must be >= 0

cnt > back is valid, this will copy the bytes we just copied, thus creating a repeating pattern with a period length of back.

Definition at line 121 of file lzo.c.

Referenced by av_lzo1x_decode().

static int get_byte

(

LZOContext *

c

)

[inline, static]

Reads one byte from the input buffer, avoiding an overrun.

Returns:

byte read

Definition at line 43 of file lzo.c.

static int get_len	(	LZOContext *	c,
		int	x,
		int	mask
	)			[inline, static]

Decodes a length value in the coding used by lzo.

Parameters:

	x	previous byte value
	mask	bits used from x

Returns:

decoded length value

Definition at line 62 of file lzo.c.

Referenced by av_lzo1x_decode().

static void memcpy_backptr	(	uint8_t *	dst,
		int	back,
		int	cnt
	)			[inline, static]

Definition at line 136 of file lzo.c.

Referenced by av_memcpy_backptr(), and copy_backptr().