ringbuf_internal.h File Reference

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Data Structures
struct	decompress_ringbuf_t
	A ring buffer used for streaming decompression. More...

Functions
void	__ringbuf_init (decompress_ringbuf_t *ringbuf, uint8_t *buf, int winsize)
	Initialize a ring buffer for streaming decompression.
void	__ringbuf_write (decompress_ringbuf_t *ringbuf, uint8_t *src, int count)
	Write an array of bytes into the ring buffer.
void	__ringbuf_copy (decompress_ringbuf_t *ringbuf, int copy_offset, uint8_t *dst, int count)
	Extract data from the ring buffer, updating it at the same time.

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

decompress_ringbuf_t

struct decompress_ringbuf_t

A ring buffer used for streaming decompression.

Data Fields
uint8_t *	ringbuf	The ring buffer itself.
unsigned int	ringbuf_size	Size of the ring buffer (power of two)
unsigned int	ringbuf_pos	Current write position in the ring buffer.

Function Documentation

__ringbuf_init()

void __ringbuf_init	(	decompress_ringbuf_t *	ringbuf,
		uint8_t *	buf,
		int	winsize
	)

Initialize a ring buffer for streaming decompression.

Parameters

ringbuf	Pointer to the ring buffer structure to initialize.
buf	Buffer to use as the ring buffer storage.
winsize	Window size (must be a power of 2).

__ringbuf_write()

void __ringbuf_write	(	decompress_ringbuf_t *	ringbuf,
		uint8_t *	src,
		int	count
	)

Write an array of bytes into the ring buffer.

Parameters

ringbuf	The ring buffer to write to.
src	The source array to write from.
count	The number of bytes to write.

__ringbuf_copy()

void __ringbuf_copy	(	decompress_ringbuf_t *	ringbuf,
		int	copy_offset,
		uint8_t *	dst,
		int	count
	)

Extract data from the ring buffer, updating it at the same time.

This function is used to implement a typical match-copy of LZ algorithms. Given the ring buffer and the position to copy from, it will copy the specified number of bytes into the destination buffer, while also updating the ring buffer with the copied data.

It correctly handles overlaps, so if copy_offset is 1 and count is 100, the last character in the ring buffer will be copied 100 times to the output (and to the ring buffer itself).

Parameters

ringbuf	The ring buffer
copy_offset	Offset to copy from, relative to the current position.
dst	Destination buffer
count	Number of bytes to copy