transmit sACN Universe Discovery lists

protocols/sacn/source.cpp

@@ -88,6 +88,85 @@ void Source::end(const uint16_t num)
 }
 
 
+/**
+ * @brief @cite sACN 12 Universe Discovery
+ *
+ * > E1.31 Universe Discovery enables other components on a network to know
+ * > which universes are being used to transmit data or synchronization
+ * > information. ... this specification requires any source intending to
+ * > comply with E1.31 to implement Universe Discovery...
+ */
+void Source::discoveryAnnounce()
+{
+  /// > \cite sACN 12.1 Universe Discovery and Termination
+  /// >
+  /// > Any source that is no longer sending any universe data may stop
+  /// > sending E1.31 Universe Discovery Packets until such time that it
+  /// > resumes transmission of E1.31 Data and/or Synchronization information.
+  if (universes_.empty())
+    return;
+
+  // destination IP
+  ipAddress ip;
+
+  // framing layer header
+  auto frmheader = new EXTENDED::discovery_header;
+  frmheader->source_name = name();
+
+  // universe discovery layer
+  EXTENDED::DISCOVERY::discovery_list_header header;
+
+  // known universes
+  std::vector<EXTENDED::DISCOVERY::discoveredUniverse> list;
+  for (const auto & [num, univ] : universes_)
+    {
+      if (univ->destination.type != ACN::SDT::SDT_ADDR_NULL)
+        continue;
+      list.emplace_back(EXTENDED::DISCOVERY::discoveredUniverse());
+      list.back().universe = num;
+    }
+
+  /// > \cite sACN 8.3 Page
+  /// >
+  /// > A single source may be transmitting on so many universes that the
+  /// > total number of universes it must include in its List of Universes
+  /// > will span multiple packets. Each one of these packets acts as a
+  /// > “page” of those universes.
+  ///
+  /// > \cite sACN 8.4 Last Page
+  /// >
+  /// > The Universe Discovery Layer's Last Page field is an 8-bit field
+  /// > indicating the number of the final page being to be transmitted. ...
+  /// > Page numbers are indexed starting at 0.
+  header.last_page = list.size() / 512;
+  for (size_t i = 0; i <= header.last_page; i++)
+    {
+      /// > The Universe Discovery Layer's Page field is an 8-bit field
+      /// > indicating the page number of this E1.31 Universe Discovery Packet.
+      /// > Page numbers are indexed, starting at 0.
+      header.page = i;
+
+      // universe discover layer data
+      EXTENDED::DISCOVERY::discovery_list_data data;
+      for (size_t n = i * 512; n < (i * 512) + 512; n++)
+        {
+          if (n > list.size())
+            break;
+          data.found.push_back(list.at(n));
+        }
+
+      // framing layer data
+      auto dlistpdu = new EXTENDED::DISCOVERY::Pdu;
+      dlistpdu->setVector(VECTOR_UNIVERSE_DISCOVERY_UNIVERSE_LIST);
+      dlistpdu->setHeader(&header);
+      dlistpdu->setData(&data);
+
+      // framing layer
+      sendExtendedFrame(VECTOR_E131_EXTENDED_DISCOVERY, frmheader, dlistpdu, ip);
+    }
+}
+
+
 /**
  * @brief Source::sendExtendedFrame
  * @param vector

protocols/sacn/source.h

@@ -51,6 +51,7 @@ public:
 
 protected:
     virtual void end(const uint16_t);
+    virtual void discoveryAnnounce();
 
     void sendExtendedFrame(const uint16_t vector,
                            ACN::PDU::pdu_header *header,