Added osg::Identifer, osg::ValueMap and osg::ValueStack classes to provide a general purpose means for storing and retrieving values from map or stack containers.

Typical use will be for storing and passing values between nodes during traversals.

include/osg/Identifier

@@ -0,0 +1,68 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2014 Robert Osfield
+ *
+ * This library is open source and may be redistributed and/or modified under
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * OpenSceneGraph Public License for more details.
+*/
+
+#ifndef OSG_IDENTIFER_H
+#define OSG_IDENTIFER_H
+
+#include <osg/Referenced>
+#include <osg/Observer>
+
+#include <string>
+#include <cctype>
+
+#define OSG_HAS_IDENTIFIER
+
+namespace osg
+{
+
+/** helper function for doing a case insenstive compare of two strings.*/
+inline bool iequals(const std::string& lhs, const std::string& rhs)
+{
+    if (lhs.size()!=rhs.size()) return false;
+
+    for(std::string::size_type i=0; i<lhs.size(); ++i)
+    {
+        if (std::tolower(lhs[i])!=std::tolower(rhs[i])) return false;
+    }
+
+    return true;
+}
+
+
+/** Unique Indentifier class to help with efficiently comparing
+  * road classification or region via pointers.*/
+class Identifier : public osg::Referenced, public osg::Observer
+{
+public:
+    static Identifier* get(const std::string& name, int number=0, osg::Referenced* first=0, osg::Referenced* second=0);
+    static Identifier* get(int number, osg::Referenced* first=0, osg::Referenced* second=0);
+    static Identifier* get(osg::Referenced* first, osg::Referenced* second=0);
+
+    const std::string& name() const { return _name; }
+    const int& number() const { return _number; }
+
+protected:
+    Identifier(const std::string& name, int number, osg::Referenced* f, osg::Referenced* s);
+    virtual ~Identifier();
+
+    virtual void objectDeleted(void* ptr);
+
+    std::string _name;
+    int         _number;
+    osg::Referenced* _first;
+    osg::Referenced* _second;
+};
+
+}
+
+#endif