X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=write_common.c;h=14ce819515010e84635e5f313f58a78071487f0f;hp=5eb6b796cbff4a8ce74fae16017e4366485ae84f;hb=d0f36435b0f81368a778fda33f3a7df86830f5ac;hpb=ec354cf583bc2838ecfac64c428d3f992681c5fc

diff --git a/write_common.c b/write_common.c
index 5eb6b796..14ce8195 100644
--- a/write_common.c
+++ b/write_common.c
@@ -7,12 +7,14 @@
 /** \file write_common.c common functions of para_audiod and para_write */
 
 #include <regex.h>
+#include <stdbool.h>
 
 #include "para.h"
 #include "string.h"
 #include "list.h"
 #include "sched.h"
 #include "ggo.h"
+#include "buffer_tree.h"
 #include "write.h"
 #include "error.h"
 
@@ -22,7 +24,7 @@ const char *writer_names[] ={WRITER_NAMES};
 /** the array of supported writers */
 struct writer writers[NUM_SUPPORTED_WRITERS] = {WRITER_ARRAY};
 
-static void wng_pre_select(__a_unused struct sched *s, struct task *t)
+static void wng_pre_select(struct sched *s, struct task *t)
 {
 	struct writer_node_group *g = container_of(t, struct writer_node_group, task);
 	int i;
@@ -36,13 +38,25 @@ static void wng_pre_select(__a_unused struct sched *s, struct task *t)
 		if (t->error < 0)
 			return;
 	}
+	/*
+	 * Force a minimal delay if something was written during the previous
+	 * call to wng_post_select(). This is necessary because the filter
+	 * chain might still have data for us which it couldn't convert during
+	 * the previous run due to its buffer size constraints. In this case we
+	 * do not want to wait until the next input data arrives as this could
+	 * lead to buffer underruns.
+	 */
+	if (g->last_written == 0)
+		return;
+	s->timeout.tv_sec = 0;
+	s->timeout.tv_usec = 1;
 }
 
 static void wng_post_select(struct sched *s, struct task *t)
 {
 	struct writer_node_group *g = container_of(t, struct writer_node_group, task);
 	int i;
-	size_t min_written = 0;
+	size_t min_written = 0, max_written = 0;
 
 	FOR_EACH_WRITER_NODE(i, g) {
 		struct writer_node *wn = &g->writer_nodes[i];
@@ -54,7 +68,9 @@ static void wng_post_select(struct sched *s, struct task *t)
 			min_written = wn->written;
 		else
 			min_written = PARA_MIN(min_written, wn->written);
+		max_written = PARA_MAX(max_written, wn->written);
 	}
+	g->last_written = max_written;
 	//PARA_INFO_LOG("loaded: %zd, min_written: %zd bytes\n", *g->loaded, min_written);
 	if (min_written) {
 		*g->loaded -= min_written;
@@ -220,6 +236,52 @@ struct writer_node_group *setup_default_wng(void)
 	wng->writer_nodes[0].conf = writers[DEFAULT_WRITER].parse_config("");
 	return wng;
 }
+
+/**
+ * Setup a writer node with the default writer.
+ *
+ * If arg is \p NULL, the OS-dependent default writer is used with an empty
+ * configuration string.  It defaults to alsa for Linux, osx for OS X, oss for
+ * *BSD and the file writer if neither of these is supported.
+ *
+ * Once the writer configuration has been retrieved, a writer node is created,
+ * its buffer tree node is added to the buffer tree as a child of the given
+ * parent.
+ *
+ * Finally, the new writer node's taks structure is initialized and registered
+ * to the paraslash scheduler.
+ *
+ * \return A pointer to the allocated writer node group.
+ */
+struct writer_node *setup_writer_node(const char *arg, struct btr_node *parent)
+{
+	struct writer_node *wn = para_calloc(sizeof(*wn));
+	struct writer *w;
+	char *name;
+
+	if (arg)
+		wn->conf = check_writer_arg(arg, &wn->writer_num);
+	else {
+		wn->writer_num = DEFAULT_WRITER;
+		wn->conf = writers[DEFAULT_WRITER].parse_config("");
+	}
+	if (!wn->conf) {
+		free(wn);
+		return NULL;
+	}
+	w = writers + wn->writer_num;
+	name = make_message("%s writer", writer_names[wn->writer_num]);
+	wn->btrn = btr_new_node(name, parent, w->execute, wn);
+	strcpy(wn->task.status, name);
+	free(name);
+	w->open(wn);
+	wn->task.post_select = w->post_select_btr;
+	wn->task.pre_select = w->pre_select_btr;
+	register_task(&wn->task);
+	return wn;
+}
+
+
 /**
  * Print the help text of all writers to stdout.
  *