track relative address offests

protocols/dmp/device.cpp

@@ -88,6 +88,23 @@ void Device::dmpSet(PDU::Message<DMP::Pdu> dmp)
 {
   auto type = std::static_pointer_cast<address_type>(dmp->header());
   auto set_data = std::static_pointer_cast<address_pair_list>(dmp->data());
+
+  for(const auto& [range, data] : set_data->properties)
+    {
+      /// \cite DMP 5.1.2 Relative Addresses
+      /// Relative addresses are used to specify an address as an offset
+      /// from the most recently used address within the same PDU Block.
+      uint32_t address = range.address;
+      if (type->relative)
+        address += last_address_used;
+
+      /// \todo do something with DMP properties
+
+      /// \cite DMP 5.1.2 Relative Addresses
+      /// If a command addresses a range of properties then a subsequent
+      /// relative address shall be relative to the last property in that range.
+      last_address_used = address;
+    }
 }