filter_common.c File Reference

Common helper functions for filter input/output. More...

#include <regex.h>
#include <sys/types.h>
#include <lopsub.h>
#include "filter_cmd.lsg.h"
#include "para.h"
#include "list.h"
#include "sched.h"
#include "fd.h"
#include "buffer_tree.h"
#include "filter.h"
#include "error.h"
#include "string.h"

Macros
#define	FOR_EACH_FILTER(j)   for (j = 1; FILTER_CMD(j); j++)
	Iterate over all filters. More...
#define	DECODER_SAMPLE_FORMAT   SF_S16_LE

Functions
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...
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	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...
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...

Detailed Description

Common helper functions for filter input/output.

Macro Definition Documentation

FOR_EACH_FILTER

#define FOR_EACH_FILTER

(

j

)

for (j = 1; FILTER_CMD(j); j++)

Iterate over all filters.

DECODER_SAMPLE_FORMAT

#define DECODER_SAMPLE_FORMAT   SF_S16_LE

Function Documentation

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.

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

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 a negative paraslash error code is returned.

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

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.

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.