X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=filter.h;h=94657a738a4ae1b620148d28400c20ed4c27a710;hp=2c1fdac1191516587502833434605fb97bb20339;hb=bda95f9508b456dcea89d300f6d4104e30ab9f3e;hpb=0750c5dfa5404cdc6baef58cc1fc6b56fc2b5f43;ds=inline

diff --git a/filter.h b/filter.h
index 2c1fdac1..94657a73 100644
--- a/filter.h
+++ b/filter.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2005-2009 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2005-2011 Andre Noll <maan@systemlinux.org>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
@@ -24,8 +24,11 @@ struct filter_node {
 	struct list_head callbacks;
 	/** A pointer to the configuration of this instance. */
 	void *conf;
+	/** The buffer tree node. */
 	struct btr_node *btrn;
+	/** The task corresponding to this filter node. */
 	struct task task;
+	/** The minimal input queue size, see \ref btr_node_status(). */
 	size_t min_iqs;
 };
 
@@ -64,7 +67,8 @@ struct filter {
 	 * Close one instance of this filter.
 	 *
 	 * Free all resources of associated with \a fn that were previously allocated
-	 * by the open() function.
+	 * by the open() function. It's OK to leave this alone if the filter does not
+	 * need any cleanups.
 	 */
 	void (*close)(struct filter_node *fn);
 	/**
@@ -80,19 +84,38 @@ struct filter {
 	 * 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;
+	/**
+	 * Set scheduler timeout and add file descriptors to fd sets.
+	 *
+	 * This function is used to control the timeout value for select. It
+	 * only allowed to decrease the current value. The second purpose of
+	 * this function is to set file descriptors to be watched by the
+	 * subsequent select call to the two fd sets.
+	 */
 	void (*pre_select)(struct sched *s, struct task *t);
 	/**
 	 * 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 set t->error to a (negative)
+	 * error code.
 	 */
 	void (*post_select)(struct sched *s, struct task *t);
+	/**
+	 * 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.
+	 */
 	btr_command_handler execute;
 };
 
@@ -100,6 +123,8 @@ 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 decoder_execute(const char *cmd, unsigned sample_rate, unsigned channels,
+		char **result);
 
 static inline void write_int16_host_endian(char *buf, int val)
 {
@@ -114,6 +139,7 @@ static inline void write_int16_host_endian(char *buf, int val)
 
 DECLARE_FILTER_INITS
 
+/** Iterate over the array of supported filters. */
 #define FOR_EACH_SUPPORTED_FILTER(j)  for (j = 0; j < NUM_SUPPORTED_FILTERS; j++)
 
 /** The filter array, one structure for each supported filter. */