Switch to side-by-side view

--- a/src/upmpd.cxx
+++ b/src/upmpd.cxx
@@ -56,6 +56,30 @@
 using namespace std;
 using namespace std::placeholders;
 using namespace UPnPP;
+
+bool OHService::getEventData(bool all, vector<string>& names, 
+                                      vector<std::string>& values)
+{
+    //LOGDEB("OHService::getEventData" << std::endl);
+
+    std::unordered_map<std::string, std::string> state, changed;
+    makestate(state);
+    if (all) {
+        changed = state;
+    } else {
+        changed = diffmaps(m_state, state);
+    }
+    m_state = state;
+
+    for (auto it = changed.begin(); it != changed.end(); it++) {
+        //LOGDEB("OHService: state change: " << it->first << " -> "
+        // << it->second << endl);
+        names.push_back(it->first);
+        values.push_back(it->second);
+    }
+
+    return true;
+}
 
 // Note: if we ever need this to work without cxx11, there is this:
 // http://www.tutok.sk/fastgl/callback.html