filter.h File Reference

Filter-related structures and exported symbols from filter_common.c. More...

Data Structures
struct	filter_node
	Describes one running instance of a filter. More...
struct	filter
	Describes a method to convert audio data. More...

Macros
#define	FILTER_CMD(_num)   (lls_cmd(_num, filter_cmd_suite))
#define	FILTER_CMD_OPT(_cmd, _opt)
#define	FILTER_CMD_OPT_RESULT(_cmd, _opt, _lpr)    (lls_opt_result(LSG_FILTER_CMD_ ## _cmd ## _OPT_ ## _opt, _lpr))
#define	FILTER_CMD_OPT_GIVEN(_cmd, _opt, _lpr)    (lls_opt_given(FILTER_CMD_OPT_RESULT(_cmd, _opt, _lpr)))
#define	FILTER_CMD_OPT_UINT32_VAL(_cmd, _opt, _lpr)    (lls_uint32_val(0, FILTER_CMD_OPT_RESULT(_cmd, _opt, _lpr)))
#define	FILTER_CMD_OPT_STRING_VAL(_cmd, _opt, _lpr)    (lls_string_val(0, FILTER_CMD_OPT_RESULT(_cmd, _opt, _lpr)))

Functions
void	print_filter_helps (bool detailed)
	Print help text of each filter to stdout. More...
void	print_filter_list (void)
	Print a short summary of all available filters to stdout. More...
int	filter_setup (const char *fa, void **conf, struct lls_parse_result **lprp)
	Parse a filter command line and call the corresponding ->setup method. More...
void	generic_filter_pre_monitor (struct sched *s, void *context)
	Request a minimal timeout if not idle. More...
int	decoder_execute (const char *cmd, unsigned sample_rate, unsigned channels, char **result)
	Execute a btr command for a decoder. More...
const struct filter *	filter_get (int filter_num)
	Obtain a reference to a filter structure. More...
const char *	filter_name (int filter_num)
	Return the name of a filter, given its number. More...

Detailed Description

Filter-related structures and exported symbols from filter_common.c.

Macro Definition Documentation

FILTER_CMD

#define FILTER_CMD

(

_num

)

(lls_cmd(_num, filter_cmd_suite))

FILTER_CMD_OPT

#define FILTER_CMD_OPT	(		_cmd,
			_opt
	)

Value:

        (lls_opt( \
        LSG_FILTER_CMD_ ## _cmd ## _OPT_ ## _opt, \
        FILTER_CMD(LSG_FILTER_CMD_CMD_ ## _cmd)))

FILTER_CMD_OPT_RESULT

#define FILTER_CMD_OPT_RESULT	(		_cmd,
			_opt,
			_lpr
	)		(lls_opt_result(LSG_FILTER_CMD_ ## _cmd ## _OPT_ ## _opt, _lpr))

FILTER_CMD_OPT_GIVEN

#define FILTER_CMD_OPT_GIVEN	(		_cmd,
			_opt,
			_lpr
	)		(lls_opt_given(FILTER_CMD_OPT_RESULT(_cmd, _opt, _lpr)))

FILTER_CMD_OPT_UINT32_VAL

#define FILTER_CMD_OPT_UINT32_VAL	(		_cmd,
			_opt,
			_lpr
	)		(lls_uint32_val(0, FILTER_CMD_OPT_RESULT(_cmd, _opt, _lpr)))

FILTER_CMD_OPT_STRING_VAL

#define FILTER_CMD_OPT_STRING_VAL	(		_cmd,
			_opt,
			_lpr
	)		(lls_string_val(0, FILTER_CMD_OPT_RESULT(_cmd, _opt, _lpr)))

Function Documentation

print_filter_helps()

void print_filter_helps

(

bool

detailed

)

Print help text of each filter to stdout.

Parameters

detailed

Whether to print short or long help.

References FOR_EACH_FILTER.

print_filter_list()

void print_filter_list

(

void

)

Print a short summary of all available filters to stdout.

For each supported filter, the filter name and the purpose text is printed in a single line. Since no options are shown, the filter list is more concise than the text obtained from print_filter_helps().

References FILTER_CMD, and FOR_EACH_FILTER.

filter_setup()

int filter_setup	(	const char *	fa,
		void **	conf,
		struct lls_parse_result **	lprp
	)

Parse a filter command line and call the corresponding ->setup method.

Parameters

fa	The filter argument.
conf	Points to filter-specific setup upon successful return.
lprp	Parsed command line options are returned here.

Check if the given filter argument starts with the name of a supported filter, optionally followed by options for this filter. If yes, call the command line parser of that filter and its ->setup method.

Returns

This function either succeeds or does not return. On success, the number of the filter is returned and conf is initialized to point to the filter configuration as returned by the filter's ->setup() method, if any. Moreover, *lprp is initialized to contain the parsed command line options. On errors, the function calls exit(EXIT_FAILURE).

References create_argv(), FILTER_CMD, free_argv(), and lls().

generic_filter_pre_monitor()

void generic_filter_pre_monitor	(	struct sched *	s,
		void *	context
	)

Request a minimal timeout if not idle.

Parameters

s	The scheduler instance.
context	Pointer to the filter node.

If the buffer tree node of the given filter node has data available (or is in error state) a minimal I/O timeout is requested from the scheduler. Otherwise the function does nothing.

References btr_node_status(), BTR_NT_INTERNAL, filter_node::btrn, filter_node::min_iqs, and sched_min_delay().

decoder_execute()

int decoder_execute	(	const char *	cmd,
		unsigned	sample_rate,
		unsigned	channels,
		char **	result
	)

Execute a btr command for a decoder.

The buffer tree nodes of the writers ask the parent nodes about sample_rate, channels count and sample format. This function is called by all decoders to answer these queries.

Parameters

cmd	The command to be executed by the child node.
sample_rate	Known to the decoder.
channels	Known to the decoder.
result	Ascii representation on the answer is stored here.

Returns

Standard.

filter_get()

const struct filter* filter_get

(

int

filter_num

)

Obtain a reference to a filter structure.

Parameters

filter_num

Between zero and NUM_SUPPORTED_FILTERS, inclusively.

Returns

Pointer to the filter identified by the given filter number, or NULL if the filter number is out of range.

See also

filter_name().

References FILTER_CMD.

filter_name()

const char* filter_name

(

int

filter_num

)

Return the name of a filter, given its number.

Parameters

filter_num

See filter_get().

Returns

A pointer to a string literal, or NULL if filter_num is out of range. The caller must not attempt to call free(3) on the returned pointer.

References FILTER_CMD.