add checkAttribute function (get/test/add: see the doc)

include/Topology/generic/attribmap.h

@@ -72,6 +72,14 @@ public:
 	template <typename T, unsigned int ORBIT>
 	AttributeHandler<T, ORBIT> getAttribute(const std::string& nameAttr) ;
 
+	/**
+	* check if an attribute exist ( get, test if valid and add if necessary)
+	* @param nameAttr attribute name
+	* @return an AttributeHandler
+	*/
+	template <typename T, unsigned int ORBIT>
+	AttributeHandler<T, ORBIT> checkAttribute(const std::string& nameAttr) ;
+
 	/**
 	 * swap the content of two attributes (efficient, only swap pointers)
 	 */

include/Topology/generic/attribmap.hpp

@@ -57,6 +57,17 @@ inline AttributeHandler<T ,ORBIT> AttribMap::getAttribute(const std::string& nam
 	return AttributeHandler<T, ORBIT>(this, amv) ;
 }
 
+template <typename T, unsigned int ORBIT>
+inline AttributeHandler<T ,ORBIT> AttribMap::checkAttribute(const std::string& nameAttr)
+{
+	AttributeHandler<T,ORBIT> att = this->getAttribute<T,ORBIT>(nameAttr);
+	if (!att.isValid())
+		att = this->addAttribute<T,ORBIT>("position");
+	return att;
+}
+
+
+
 template <typename T, unsigned int ORBIT>
 inline bool AttribMap::swapAttributes(AttributeHandler<T, ORBIT>& attr1, AttributeHandler<T, ORBIT>& attr2)
 {