src/fifo_buffer.h File Reference

This is a general purpose FIFO buffer library. More...

#include <stdbool.h>
#include <stddef.h>

Go to the source code of this file.

Functions
struct fifo_buffer *	fifo_buffer_new (size_t size)
	Creates a new #fifo_buffer object.
struct fifo_buffer *	fifo_buffer_realloc (struct fifo_buffer *buffer, size_t new_size)
	Change the capacity of the #fifo_buffer, while preserving existing data.
void	fifo_buffer_free (struct fifo_buffer *buffer)
	Frees the resources consumed by this #fifo_buffer object.
size_t	fifo_buffer_capacity (const struct fifo_buffer *buffer)
	Return the capacity of the buffer, i.e.
size_t	fifo_buffer_available (const struct fifo_buffer *buffer)
	Return the number of bytes currently stored in the buffer.
void	fifo_buffer_clear (struct fifo_buffer *buffer)
	Clears all data currently in this #fifo_buffer object.
const void *	fifo_buffer_read (const struct fifo_buffer *buffer, size_t *length_r)
	Reads from the beginning of the buffer.
void	fifo_buffer_consume (struct fifo_buffer *buffer, size_t length)
	Marks data at the beginning of the buffer as "consumed".
void *	fifo_buffer_write (struct fifo_buffer *buffer, size_t *max_length_r)
	Prepares writing to the buffer.
void	fifo_buffer_append (struct fifo_buffer *buffer, size_t length)
	Commits the write operation initiated by fifo_buffer_write().
bool	fifo_buffer_is_empty (struct fifo_buffer *buffer)
	Checks if the buffer is empty.
bool	fifo_buffer_is_full (struct fifo_buffer *buffer)
	Checks if the buffer is full.

---

Detailed Description

This is a general purpose FIFO buffer library.

You may append data at the end, while another instance reads data from the beginning. It is optimized for zero-copy usage: you get pointers to the real buffer, where you may operate on.

This library is not thread safe.

Definition in file fifo_buffer.h.

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Function Documentation

void fifo_buffer_append	(	struct fifo_buffer *	buffer,
		size_t	length
	)

Commits the write operation initiated by fifo_buffer_write().

Parameters:

buffer	the #fifo_buffer object
length	the number of bytes which were written

size_t fifo_buffer_available

(

const struct fifo_buffer *

buffer

)

Return the number of bytes currently stored in the buffer.

size_t fifo_buffer_capacity

(

const struct fifo_buffer *

buffer

)

Return the capacity of the buffer, i.e.

the size that was passed to fifo_buffer_new().

void fifo_buffer_clear

(

struct fifo_buffer *

buffer

)

Clears all data currently in this #fifo_buffer object.

This does not overwrite the actuall buffer; it just resets the internal pointers.

void fifo_buffer_consume	(	struct fifo_buffer *	buffer,
		size_t	length
	)

Marks data at the beginning of the buffer as "consumed".

Parameters:

buffer	the #fifo_buffer object
length	the number of bytes which were consumed

void fifo_buffer_free

(

struct fifo_buffer *

buffer

)

Frees the resources consumed by this #fifo_buffer object.

bool fifo_buffer_is_empty

(

struct fifo_buffer *

buffer

)

Checks if the buffer is empty.

bool fifo_buffer_is_full

(

struct fifo_buffer *

buffer

)

Checks if the buffer is full.

struct fifo_buffer* fifo_buffer_new

(

size_t

size

)

[read]

Creates a new #fifo_buffer object.

Free this object with fifo_buffer_free().

Parameters:

size	the size of the buffer in bytes

Returns:

the new #fifo_buffer object

const void* fifo_buffer_read	(	const struct fifo_buffer *	buffer,
		size_t *	length_r
	)

Reads from the beginning of the buffer.

To remove consumed data from the buffer, call fifo_buffer_consume().

Parameters:

buffer	the #fifo_buffer object
length_r	the maximum amount to read is returned here

Returns:

a pointer to the beginning of the buffer, or NULL if the buffer is empty

struct fifo_buffer* fifo_buffer_realloc	(	struct fifo_buffer *	buffer,
		size_t	new_size
	)		[read]

Change the capacity of the #fifo_buffer, while preserving existing data.

Parameters:

buffer	the old buffer, may be NULL
new_size	the requested new size of the #fifo_buffer; must not be smaller than the data which is stored in the old buffer

Returns:

the new buffer, may be NULL if the requested new size is 0

void* fifo_buffer_write	(	struct fifo_buffer *	buffer,
		size_t *	max_length_r
	)

Prepares writing to the buffer.

This returns a buffer which you can write to. To commit the write operation, call fifo_buffer_append().

Parameters:

buffer	the #fifo_buffer object
max_length_r	the maximum amount to write is returned here

Returns:

a pointer to the end of the buffer, or NULL if the buffer is already full