External I/O plugin SDK

Collaboration diagram for External I/O plugin SDK:

Data Structures
struct	snd_pcm_ioplug_t
struct	snd_pcm_ioplug_callback_t

Macros
#define	SND_PCM_IOPLUG_FLAG_LISTED   (1<<0)
#define	SND_PCM_IOPLUG_FLAG_MONOTONIC   (1<<1)
#define	SND_PCM_IOPLUG_FLAG_BOUNDARY_WA   (1<<2)
#define	SND_PCM_IOPLUG_VERSION_MAJOR   1
#define	SND_PCM_IOPLUG_VERSION_MINOR   0
#define	SND_PCM_IOPLUG_VERSION_TINY   2
#define	SND_PCM_IOPLUG_VERSION

Typedefs
typedef snd_pcm_ioplug	snd_pcm_ioplug_t
typedef snd_pcm_ioplug_callback	snd_pcm_ioplug_callback_t

Enumerations
enum	{   SND_PCM_IOPLUG_HW_ACCESS = 0 , SND_PCM_IOPLUG_HW_FORMAT , SND_PCM_IOPLUG_HW_CHANNELS , SND_PCM_IOPLUG_HW_RATE ,   SND_PCM_IOPLUG_HW_PERIOD_BYTES , SND_PCM_IOPLUG_HW_BUFFER_BYTES , SND_PCM_IOPLUG_HW_PERIODS , SND_PCM_IOPLUG_HW_PARAMS }

Functions
int	snd_pcm_ioplug_create (snd_pcm_ioplug_t *io, const char *name, snd_pcm_stream_t stream, int mode)
	Create an ioplug instance. More...
int	snd_pcm_ioplug_delete (snd_pcm_ioplug_t *io)
	Delete the ioplug instance. More...
int	snd_pcm_ioplug_reinit_status (snd_pcm_ioplug_t *ioplug)
	Reinitialize the poll and mmap status. More...
const snd_pcm_channel_area_t *	snd_pcm_ioplug_mmap_areas (snd_pcm_ioplug_t *ioplug)
	Get mmap area of ioplug. More...
void	snd_pcm_ioplug_params_reset (snd_pcm_ioplug_t *io)
	Reset ioplug parameters. More...
int	snd_pcm_ioplug_set_param_minmax (snd_pcm_ioplug_t *io, int type, unsigned int min, unsigned int max)
	Set parameter as the min/max values. More...
int	snd_pcm_ioplug_set_param_list (snd_pcm_ioplug_t *io, int type, unsigned int num_list, const unsigned int *list)
	Set parameter as the list. More...
int	snd_pcm_ioplug_set_state (snd_pcm_ioplug_t *ioplug, snd_pcm_state_t state)
	Change the ioplug PCM status. More...
snd_pcm_uframes_t	snd_pcm_ioplug_avail (const snd_pcm_ioplug_t *const ioplug, const snd_pcm_uframes_t hw_ptr, const snd_pcm_uframes_t appl_ptr)
	Get the available frames. This function can be used to calculate the the available frames before calling snd_pcm_avail_update() More...
snd_pcm_uframes_t	snd_pcm_ioplug_hw_avail (const snd_pcm_ioplug_t *const ioplug, const snd_pcm_uframes_t hw_ptr, const snd_pcm_uframes_t appl_ptr)
	Get the available frames. This function can be used to calculate the the available frames before calling snd_pcm_avail_update() More...

Detailed Description

See the PCM (digital audio) interface page for more details.

Macro Definition Documentation

SND_PCM_IOPLUG_FLAG_BOUNDARY_WA

#define SND_PCM_IOPLUG_FLAG_BOUNDARY_WA   (1<<2)

hw pointer wrap around at boundary instead of buffer_size

SND_PCM_IOPLUG_FLAG_LISTED

#define SND_PCM_IOPLUG_FLAG_LISTED   (1<<0)

list up this PCM

SND_PCM_IOPLUG_FLAG_MONOTONIC

#define SND_PCM_IOPLUG_FLAG_MONOTONIC   (1<<1)

monotonic timestamps

SND_PCM_IOPLUG_VERSION

#define SND_PCM_IOPLUG_VERSION

Value:

                     ((SND_PCM_IOPLUG_VERSION_MAJOR<<16) |\
                     (SND_PCM_IOPLUG_VERSION_MINOR<<8) |\
                     (SND_PCM_IOPLUG_VERSION_TINY))

IO-plugin protocol version

SND_PCM_IOPLUG_VERSION_MAJOR

#define SND_PCM_IOPLUG_VERSION_MAJOR   1

Protocol major version

SND_PCM_IOPLUG_VERSION_MINOR

#define SND_PCM_IOPLUG_VERSION_MINOR   0

Protocol minor version

SND_PCM_IOPLUG_VERSION_TINY

#define SND_PCM_IOPLUG_VERSION_TINY   2

Protocol tiny version

Typedef Documentation

snd_pcm_ioplug_callback_t

typedef struct snd_pcm_ioplug_callback snd_pcm_ioplug_callback_t

Callback table of ioplug

snd_pcm_ioplug_t

typedef struct snd_pcm_ioplug snd_pcm_ioplug_t

I/O plugin handle

Enumeration Type Documentation

anonymous enum

anonymous enum

hw constraints for ioplug

Enumerator
SND_PCM_IOPLUG_HW_ACCESS	access type
SND_PCM_IOPLUG_HW_FORMAT	format
SND_PCM_IOPLUG_HW_CHANNELS	channels
SND_PCM_IOPLUG_HW_RATE	rate
SND_PCM_IOPLUG_HW_PERIOD_BYTES	period bytes
SND_PCM_IOPLUG_HW_BUFFER_BYTES	buffer bytes
SND_PCM_IOPLUG_HW_PERIODS	number of periods
SND_PCM_IOPLUG_HW_PARAMS	max number of hw constraints

Function Documentation

snd_pcm_ioplug_avail()

snd_pcm_uframes_t snd_pcm_ioplug_avail	(	const snd_pcm_ioplug_t *const	ioplug,
		const snd_pcm_uframes_t	hw_ptr,
		const snd_pcm_uframes_t	appl_ptr
	)

Get the available frames. This function can be used to calculate the the available frames before calling snd_pcm_avail_update()

Parameters

ioplug	the ioplug handle
hw_ptr	hardware pointer in frames
appl_ptr	application pointer in frames

Returns

available frames for the application

snd_pcm_ioplug_create()

int snd_pcm_ioplug_create	(	snd_pcm_ioplug_t *	ioplug,
		const char *	name,
		snd_pcm_stream_t	stream,
		int	mode
	)

Create an ioplug instance.

Parameters

ioplug	the ioplug handle
name	name of PCM
stream	stream direction
mode	PCM open mode

Returns

0 if successful, or a negative error code

Creates the ioplug instance.

The callback is the mandatory field of ioplug handle. At least, start, stop and pointer callbacks must be set before calling this function.

snd_pcm_ioplug_delete()

int snd_pcm_ioplug_delete

(

snd_pcm_ioplug_t *

ioplug

)

Delete the ioplug instance.

Parameters

ioplug

the ioplug handle

Returns

0 if successful, or a negative error code

snd_pcm_ioplug_hw_avail()

snd_pcm_uframes_t snd_pcm_ioplug_hw_avail	(	const snd_pcm_ioplug_t *const	ioplug,
		const snd_pcm_uframes_t	hw_ptr,
		const snd_pcm_uframes_t	appl_ptr
	)

Get the available frames. This function can be used to calculate the the available frames before calling snd_pcm_avail_update()

Parameters

ioplug	the ioplug handle
hw_ptr	hardware pointer in frames
appl_ptr	application pointer in frames

Returns

available frames for the hardware

snd_pcm_ioplug_mmap_areas()

const snd_pcm_channel_area_t * snd_pcm_ioplug_mmap_areas

(

snd_pcm_ioplug_t *

ioplug

)

Get mmap area of ioplug.

Parameters

ioplug

the ioplug handle

Returns

the mmap channel areas if available, or NULL

Returns the mmap channel areas if available. When mmap_rw field is not set, this function always returns NULL.

snd_pcm_ioplug_params_reset()

void snd_pcm_ioplug_params_reset

(

snd_pcm_ioplug_t *

ioplug

)

Reset ioplug parameters.

Parameters

ioplug

the ioplug handle

Resets the all parameters for the given ioplug handle.

snd_pcm_ioplug_reinit_status()

int snd_pcm_ioplug_reinit_status

(

snd_pcm_ioplug_t *

ioplug

)

Reinitialize the poll and mmap status.

Parameters

ioplug

the ioplug handle

Returns

0 if successful, or a negative error code

Reinitializes the poll and the mmap status of the PCM. Call this function to propagate the status change in the ioplug instance to its PCM internals.

snd_pcm_ioplug_set_param_list()

int snd_pcm_ioplug_set_param_list	(	snd_pcm_ioplug_t *	ioplug,
		int	type,
		unsigned int	num_list,
		const unsigned int *	list
	)

Set parameter as the list.

Parameters

ioplug	the ioplug handle
type	parameter type
num_list	number of available values
list	the list of available values

Returns

0 if successful, or a negative error code

Sets the parameter as the list. The available values of the given parameter type is restricted to the ones of the given list.

snd_pcm_ioplug_set_param_minmax()

int snd_pcm_ioplug_set_param_minmax	(	snd_pcm_ioplug_t *	ioplug,
		int	type,
		unsigned int	min,
		unsigned int	max
	)

Set parameter as the min/max values.

Parameters

ioplug	the ioplug handle
type	parameter type
min	the minimum value
max	the maximum value

Returns

0 if successful, or a negative error code

Sets the parameter as the min/max values. The available values of the given parameter type is restricted between the given minimum and maximum values.

snd_pcm_ioplug_set_state()

int snd_pcm_ioplug_set_state	(	snd_pcm_ioplug_t *	ioplug,
		snd_pcm_state_t	state
	)

Change the ioplug PCM status.

Parameters

ioplug	the ioplug handle
state	the PCM status

Returns

zero if successful or a negative error code

Changes the PCM status of the ioplug to the given value. This function can be used for external plugins to notify the status change, e.g. XRUN.