From fbe5ef6087fa6ff9628c5faccbb4974a72f44c25 Mon Sep 17 00:00:00 2001
From: Lorenz Meier <lm@inf.ethz.ch>
Date: Sun, 30 Aug 2015 00:12:33 +0200
Subject: [PATCH] uORB: Provide used group count

---
 src/modules/uORB/uORB.cpp | 14 ++++++++++++++
 src/modules/uORB/uORB.h   |  8 ++++++++
 2 files changed, 22 insertions(+)

diff --git a/src/modules/uORB/uORB.cpp b/src/modules/uORB/uORB.cpp
index d292628be0..c8920607ac 100644
--- a/src/modules/uORB/uORB.cpp
+++ b/src/modules/uORB/uORB.cpp
@@ -260,6 +260,20 @@ int  orb_exists(const struct orb_metadata *meta, int instance)
 	return uORB::Manager::get_instance()->orb_exists(meta, instance);
 }
 
+/**
+ * Get the number of published instances of a topic group
+ *
+ * @param meta    ORB topic metadata.
+ * @return    The number of published instances of this topic
+ */
+int  orb_group_count(const struct orb_metadata *meta)
+{
+	unsigned group_count = 0;
+	while (!uORB::Manager::get_instance()->orb_exists(meta, group_count++)) {};
+
+	return group_count;
+}
+
 /**
  * Return the priority of the topic
  *
diff --git a/src/modules/uORB/uORB.h b/src/modules/uORB/uORB.h
index 7b40cff219..c887925fcf 100644
--- a/src/modules/uORB/uORB.h
+++ b/src/modules/uORB/uORB.h
@@ -328,6 +328,14 @@ extern int	orb_stat(int handle, uint64_t *time) __EXPORT;
  */
 extern int	orb_exists(const struct orb_metadata *meta, int instance) __EXPORT;
 
+/**
+ * Get the number of published instances of a topic group
+ *
+ * @param meta    ORB topic metadata.
+ * @return    The number of published instances of this topic
+ */
+extern int	orb_group_count(const struct orb_metadata *meta) __EXPORT;
+
 /**
  * Return the priority of the topic
  *