/*
- * Copyright (C) 2005-2010 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>
*
* Licensed under the GPL v2. For licencing details see COPYING.
*/
struct list_head callbacks;
/** A pointer to the configuration of this instance. */
void *conf;
+ /** The buffer tree node. */
struct btr_node *btrn;
- struct task task;
+ /** The task corresponding to this filter node. */
+ struct task *task;
+ /** The minimal input queue size, see \ref btr_node_status(). */
size_t min_iqs;
};
/**
* Open one instance of this filter.
*
- * This should allocate the output buffer of the given filter node and do any
- * other filter-specific preparations like initializing the private_data member
- * of \a fn suitably. The open function is assumed to succeed.
+ * This should allocate the output buffer of the given filter node and
+ * do any other filter-specific preparations like initializing the
+ * private_data member of \a fn suitably. The open function is
+ * optional, If it is provided, it is assumed to succeed.
*/
void (*open)(struct filter_node *fn);
/**
* Close one instance of this filter.
*
- * Free all resources of associated with \a fn that were previously allocated
- * by the open() function. It's OK to leave this alone if the filter does not
- * need any cleanups.
+ * Free all resources associated with \a fn that were previously
+ * allocated by the open() function. It's OK to set this to NULL if the
+ * filter does not need to perform any cleanup operation.
*/
void (*close)(struct filter_node *fn);
/**
* argv. On failure, a negative paraslash error code must be returned.
*/
int (*parse_config)(int argc, char **argv, void **config);
+ /**
+ * Deallocate the memory for the configuration.
+ *
+ * This is called to free whatever ->parse_config() has allocated.
+ */
void (*free_config)(void *conf);
/** The help texts for this filter. */
struct ggo_help help;
- void (*pre_select)(struct sched *s, struct task *t);
+ /**
+ * Set scheduler timeout and add file descriptors to fd sets.
+ *
+ * This function controls the timeout value for the next call to
+ * select(2). It may decrease the current timeout but shall never
+ * increase it. The second purpose of this function is to add file
+ * descriptors to the two fd sets of the sched structure. The
+ * descriptors in these sets will be watched by the subsequent
+ * select(2) call.
+ */
+ void (*pre_select)(struct sched *s, void *context);
/**
* Convert (filter) the given data.
*
- * Pointer to the converting function of the filter. It should convert as
- * input data as possible. On errors, the post_select function is supposed
- * to set t->error to a (negative) error code.
+ * Pointer to the converting function of the filter. On errors, the
+ * post_select function is supposed to return a negative error code.
+ */
+ int (*post_select)(struct sched *s, void *context);
+ /**
+ * Answer a buffer tree query.
+ *
+ * This optional function pointer is used for inter node communications
+ * of the buffer tree nodes. See \ref btr_command_handler for details.
*/
- void (*post_select)(struct sched *s, struct task *t);
btr_command_handler execute;
};
void filter_init(void);
-int check_filter_arg(char *filter_arg, void **conf);
-void print_filter_helps(int detailed);
-void generic_filter_pre_select(struct sched *s, struct task *t);
+int check_filter_arg(const char *fa, void **conf);
+void print_filter_helps(unsigned flags);
+void generic_filter_pre_select(struct sched *s, void *context);
+int decoder_execute(const char *cmd, unsigned sample_rate, unsigned channels,
+ char **result);
static inline void write_int16_host_endian(char *buf, int val)
{
DECLARE_FILTER_INITS
-#define FOR_EACH_SUPPORTED_FILTER(j) for (j = 0; j < NUM_SUPPORTED_FILTERS; j++)
-
-/** The filter array, one structure for each supported filter. */
-extern struct filter filters[NUM_SUPPORTED_FILTERS];
+const struct filter *filter_get(int filter_num);