diff -r d56fad02dc55 -r 9bf990cb066d src/hugo/map_bits.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hugo/map_bits.h	Mon Sep 13 20:05:13 2004 +0000
@@ -0,0 +1,52 @@
+// -*- c++ -*- 
+#ifndef MAP_BITS_H
+#define MAP_BITS_H
+
+///\ingroup graphmaps
+///\file
+///\brief Some utils to help implement maps.
+
+namespace hugo {
+
+
+  /// \addtogroup graphmaps
+  /// @{
+
+  /// Helper class to get information about the key type.
+  template <typename Graph, typename KeyIt>
+  struct KeyInfo {};
+
+  template <typename Graph>
+  struct KeyInfo<Graph, typename Graph::NodeIt> {
+    static int maxId(const Graph& graph) {
+      return graph.maxNodeId();
+    }
+    static int id(const Graph& graph, const typename Graph::Node& node) {
+      return graph.id(node);
+    }
+  };
+
+  template <typename Graph>
+  struct KeyInfo<Graph, typename Graph::EdgeIt> {
+    static int maxId(const Graph& graph) {
+      return graph.maxEdgeId();
+    }
+    static int id(const Graph& graph, const typename Graph::Edge& edge) {
+      return graph.id(edge);
+    }
+  };
+
+  template <typename Graph>
+  struct KeyInfo<Graph, typename Graph::SymEdgeIt> {
+    static int maxId(const Graph& graph) {
+      return graph.maxEdgeId() >> 1;
+    }
+    static int id(const Graph& graph, const typename Graph::Edge& edge) {
+      return graph.id(edge) >> 1;
+    }
+  };
+
+  /// @}
+}
+
+#endif