Ring buffer library

The ring buffer library implements ring (circular) buffer where bytes can be read and written independently.

A ring buffer is particularly useful in device drivers where data can come in through interrupts.

Data Structures
struct	ringbuf
	Structure that holds the state of a ring buffer. More...

Files
file	ringbuf.h
	Header file for the ring buffer library

Functions
int	ringbuf_elements (struct ringbuf *r)
	Get the number of elements currently in the ring buffer. More...
int	ringbuf_get (struct ringbuf *r)
	Get a byte from the ring buffer. More...
void	ringbuf_init (struct ringbuf *r, uint8_t *a, uint8_t size_power_of_two)
	Initialize a ring buffer. More...
int	ringbuf_put (struct ringbuf *r, uint8_t c)
	Insert a byte into the ring buffer. More...
int	ringbuf_size (struct ringbuf *r)
	Get the size of a ring buffer. More...

Variables
uint8_t *	ringbuf::data
uint8_t	ringbuf::get_ptr
uint8_t	ringbuf::mask
uint8_t	ringbuf::put_ptr

int ringbuf_elements

(

struct ringbuf *

r

)

Get the number of elements currently in the ring buffer.

Parameters

r	A pointer to a struct ringbuf to hold the state of the ring buffer

Returns

The number of elements in the buffer.

References get_ptr, mask, and put_ptr.

int ringbuf_get

(

struct ringbuf *

r

)

Get a byte from the ring buffer.

Parameters

r	A pointer to a struct ringbuf to hold the state of the ring buffer

Returns

The data from the buffer, or -1 if the buffer was empty

        This function removes a byte from the ring buffer. It
        is safe to call this function from an interrupt
        handler.

References c, data, get_ptr, mask, and put_ptr.

Referenced by PROCESS_THREAD().

void ringbuf_init	(	struct ringbuf *	r,
		uint8_t *	a,
		uint8_t	size_power_of_two
	)

Initialize a ring buffer.

Parameters

r	A pointer to a struct ringbuf to hold the state of the ring buffer
a	A pointer to an array to hold the data in the buffer
size_power_of_two	The size of the ring buffer, which must be a power of two This function initiates a ring buffer. The data in the buffer is stored in an external array, to which a pointer must be supplied. The size of the ring buffer must be a power of two and cannot be larger than 128 bytes.

References data, get_ptr, mask, and put_ptr.

Referenced by serial_line_init().

int ringbuf_put	(	struct ringbuf *	r,
		uint8_t	c
	)

Insert a byte into the ring buffer.

Parameters

r	A pointer to a struct ringbuf to hold the state of the ring buffer
c	The byte to be written to the buffer

Returns

Non-zero if there data could be written, or zero if the buffer was full.

        This function inserts a byte into the ring buffer. It
        is safe to call this function from an interrupt
        handler.

References c, data, get_ptr, mask, and put_ptr.

Referenced by serial_line_input_byte().

int ringbuf_size

(

struct ringbuf *

r

)

Get the size of a ring buffer.

Parameters

r	A pointer to a struct ringbuf to hold the state of the ring buffer

Returns

The size of the buffer.

References mask.

uint8_t* ringbuf::data

Referenced by ringbuf_get(), ringbuf_init(), and ringbuf_put().

uint8_t ringbuf::get_ptr

Referenced by ringbuf_elements(), ringbuf_get(), ringbuf_init(), and ringbuf_put().

uint8_t ringbuf::mask

Referenced by ringbuf_elements(), ringbuf_get(), ringbuf_init(), ringbuf_put(), and ringbuf_size().

uint8_t ringbuf::put_ptr

Referenced by ringbuf_elements(), ringbuf_get(), ringbuf_init(), and ringbuf_put().