osrm startup helpers added

osrm/lib/destination.lua

@@ -0,0 +1,29 @@
+local Destination = {}
+
+function Destination.get_directional_tag(way, is_forward, tag)
+  local v
+  if is_forward then
+    v = way:get_value_by_key(tag .. ':forward') or way:get_value_by_key(tag)
+  else
+    v = way:get_value_by_key(tag .. ':backward') or way:get_value_by_key(tag)
+  end
+  if v then
+    return v.gsub(v, ';', ', ')
+  end
+end
+
+-- Assemble destination as: "A59: Düsseldorf, Köln"
+--          destination:ref  ^    ^  destination
+
+function Destination.get_destination(way, is_forward)
+  ref  = Destination.get_directional_tag(way, is_forward, 'destination:ref')
+  dest = Destination.get_directional_tag(way, is_forward, 'destination')
+  street = Destination.get_directional_tag(way, is_forward, 'destination:street')
+  if ref and dest then
+    return ref .. ': ' .. dest
+  else
+    return ref or dest or street or ''
+  end
+end
+
+return Destination