2 files changed, 28 insertions, 5 deletions

diff --git a/lib/element_impl.hpp b/lib/element_impl.hpp
index ffdb171..f09ddc8 100644
--- a/lib/element_impl.hpp
+++ b/lib/element_impl.hpp
@@ -25,8 +25,17 @@
 #include <gr_types.h>
 #include <vector>
 
-static const int STATE_INERT = 0;
-static const int STATE_ACTIVE = 1;
+struct TopBlockUpdateEvent
+{
+    enum
+    {
+        UPDATE,
+        ACTIVE,
+        INERT,
+        HINT,
+    } state;
+    size_t hint;
+};
 
 static inline int mylround(double x)
 {
diff --git a/lib/top_block.cpp b/lib/top_block.cpp
index 62cc3d2..0fade0d 100644
--- a/lib/top_block.cpp
+++ b/lib/top_block.cpp
@@ -34,17 +34,31 @@ TopBlock::TopBlock(const std::string &name):
 
 void TopBlock::update(void)
 {
-    (*this)->executor.update();
+    TopBlockUpdateEvent event;
+    event.state = TopBlockUpdateEvent::UPDATE;
+    (*this)->executor.update(event);
+}
+
+void TopBlock::set_buffer_hint(const size_t hint)
+{
+    TopBlockUpdateEvent event;
+    event.state = TopBlockUpdateEvent::HINT;
+    event.hint = hint;
+    (*this)->executor.update(event);
 }
 
 void TopBlock::start(void)
 {
-    (*this)->executor.set_state(STATE_ACTIVE);
+    TopBlockUpdateEvent event;
+    event.state = TopBlockUpdateEvent::ACTIVE;
+    (*this)->executor.update(event);
 }
 
 void TopBlock::stop(void)
 {
-    (*this)->executor.set_state(STATE_INERT);
+    TopBlockUpdateEvent event;
+    event.state = TopBlockUpdateEvent::INERT;
+    (*this)->executor.update(event);
 }
 
 void TopBlock::wait(void)