TPCircularBuffer.h File Reference

#include <stdbool.h>
#include <string.h>
#include <assert.h>
#include <stdatomic.h>

Go to the source code of this file.

Classes
struct	TPCircularBuffer

Macros
#define	TPCircularBufferInit(buffer, length)   _TPCircularBufferInit(buffer, length, sizeof(*buffer))
	Initialise buffer.

Functions
bool	_TPCircularBufferInit (TPCircularBuffer *buffer, int32_t length, size_t structSize)
void	TPCircularBufferCleanup (TPCircularBuffer *buffer)
	Cleanup buffer.
void	TPCircularBufferClear (TPCircularBuffer *buffer)
	Clear buffer.
void	TPCircularBufferSetAtomic (TPCircularBuffer *buffer, bool atomic)
	Set the atomicity.
	return (void *)((char *) buffer-> buffer+buffer->tail)
	if (buffer->atomic)
	assert (buffer->fillCount >=0)
	assert (buffer->fillCount<=buffer->length)
	if (space< len) return false
	memcpy (ptr, src, len)
	TPCircularBufferProduce (buffer, len)

Variables
static __inline__ int32_t *	availableBytes
if availableBytes return	NULL
static __inline__ int32_t	amount
	else
static __inline__ const void *	src
static __inline__ const void int32_t	len
void *	ptr = TPCircularBufferHead(buffer, &space)
return	true
buffer	fillCount = amount

---

Class Documentation

struct TPCircularBuffer

Class Members
void *	buffer
int32_t	length
int32_t	tail
int32_t	head
volatile atomic_int	fillCount
bool	atomic

Macro Definition Documentation

#define TPCircularBufferInit	(		buffer,
			length
	)		_TPCircularBufferInit(buffer, length, sizeof(*buffer))

Initialise buffer.

Note that the length is advisory only: Because of the way the memory mirroring technique works, the true buffer length will be multiples of the device page size (e.g. 4096 bytes)

If you intend to use the AudioBufferList utilities, you should always allocate a bit more space than you need for pure audio data, so there's room for the metadata. How much extra is required depends on how many AudioBufferList structures are used, which is a function of how many audio frames each buffer holds. A good rule of thumb is to add 15%, or at least another 2048 bytes or so.

Parameters

buffer	Circular buffer
length	Length of buffer

Function Documentation

bool _TPCircularBufferInit	(	TPCircularBuffer *	buffer,
		int32_t	length,
		size_t	structSize
	)

void TPCircularBufferCleanup

(

TPCircularBuffer *

buffer

)

Cleanup buffer.

Releases buffer resources.

void TPCircularBufferClear

(

TPCircularBuffer *

buffer

)

Clear buffer.

Resets buffer to original, empty state.

This is safe for use by consumer while producer is accessing buffer.

void TPCircularBufferSetAtomic	(	TPCircularBuffer *	buffer,
		bool	atomic
	)

Set the atomicity.

If you set the atomiticy to false using this method, the buffer will not use atomic operations. This can be used to give the compiler a little more optimisation opportunities when the buffer is only used on one thread.

Important note: Only set this to false if you know what you're doing!

The default value is true (the buffer will use atomic operations)

Parameters

buffer	Circular buffer
atomic	Whether the buffer is atomic (default true)

return

(

void *

)

-> buffer+buffer->tail)

if

(

buffer->

atomic

)

assert

(

buffer->fillCount >=

0

)

assert

(

buffer->fillCount<=buffer->

length

)

if

(

)

memcpy	(	ptr	,
		src	,
		len
	)

TPCircularBufferProduce	(	buffer	,
		len
	)

Variable Documentation

static __inline__ int32_t * availableBytes

Initial value:

{
 *availableBytes = buffer->fillCount

if availableBytes return NULL

static __inline__ int32_t amount

Initial value:

{
 buffer->tail = (buffer->tail + amount) % buffer->length

else

Initial value:

{
 buffer->fillCount -= amount

__inline__ const void* src

__inline__ const void int32_t len

Initial value:

{
 int32_t space

void* ptr = TPCircularBufferHead(buffer, &space)

return true

buffer fillCount = amount