X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=filter.h;h=0bd546903927d412fccef946cf8f43783ed8bc70;hp=0808059dac3f7450aaa73c27d6afd4d382c62e94;hb=5ff39998bf0ce71bd8fc8d0f002ceb81b711992f;hpb=b62e2796b85c7d7f3138fe729f4637853e0fafe0

diff --git a/filter.h b/filter.h
index 0808059d..0bd54690 100644
--- a/filter.h
+++ b/filter.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2005-2011 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>
  *
  * 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;
-	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;
 };
 
@@ -55,17 +58,18 @@ struct filter {
 	/**
 	 * 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);
 	/**
@@ -93,20 +97,21 @@ struct filter {
 	/**
 	 * 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.
+	 * 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, struct task *t);
+	void (*pre_select)(struct sched *s, void *context);
 	/**
 	 * Convert (filter) the given data.
 	 *
 	 * 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.
+	 * post_select function is supposed to return a negative error code.
 	 */
-	void (*post_select)(struct sched *s, struct task *t);
+	int (*post_select)(struct sched *s, void *context);
 	/**
 	 * Answer a buffer tree query.
 	 *
@@ -117,9 +122,9 @@ struct filter {
 };
 
 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);
 
@@ -136,7 +141,4 @@ 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);