Added class template visitor_base.

src/whiteboard/visitor.hpp

@@ -20,13 +20,90 @@
 #ifndef WB_VISITOR_HPP_
 #define WB_VISITOR_HPP_
 
+#include "action.hpp"
+#include "side_actions.hpp"
 #include "typedefs.hpp"
 
+#include "play_controller.hpp"
+#include "resources.hpp"
+#include "team.hpp"
+
 #include <boost/noncopyable.hpp>
 
 namespace wb
 {
 
+/**
+ * visitor_base: A base class template, using the so-called CRTP
+ * If you want visit_all() and reverse_visit_all() in your class,
+ *   you should derive from this class.
+ * Derived classes can "override" the following:
+ *   visit, pre_visit_team, post_visit_team
+ * Derived classes should declare visitor_base<Derived> as a friend, or
+ *   else make the overridden functions public.
+ * I recommend making the inheritance private or protected.
+ */
+template<typename Derived>
+class visitor_base
+{
+public:
+	void visit_all() {visit_all_helper<false>();}
+	void reverse_visit_all() {visit_all_helper<true>();}
+
+protected:
+	/**
+	 * visit():
+	 *   @return Whether or not to continue any visitation after this action.
+	 * The fcn is commented out because derived classes are required to implement it.
+	 */
+	//bool visit(size_t team_index, team&, side_actions&, side_actions::iterator);
+
+	///@return Whether or not to visit any of the contents of sa.
+	bool pre_visit_team(size_t team_index, team& t, side_actions& sa) {return true;}
+	///@return Whether or not to visit any more teams after this one.
+	bool post_visit_team(size_t team_index, team& t, side_actions& sa) {return true;}
+
+private:
+	template<bool reverse>
+	void visit_all_helper()
+	{
+		Derived* const new_this = static_cast<Derived*>(this);
+
+		size_t const current_team = resources::controller->current_side() - 1;
+		size_t const num_teams = resources::teams->size();
+		for(size_t iteration = 0; iteration < num_teams; ++iteration)
+		{
+			size_t const team_index
+					= (current_team+num_teams+(reverse? -1-iteration: iteration)) % num_teams;
+			team& t = resources::teams->at(team_index);
+			side_actions& sa = *t.get_side_actions();
+			if(!new_this->pre_visit_team(team_index,t,sa))
+				continue; //< Skip this team's actions
+
+			if(reverse)
+			{
+				side_actions::reverse_iterator itor = sa.rbegin();
+				side_actions::reverse_iterator end  = sa.rend();
+				while(itor!=end) {
+					++itor;
+					if(!new_this->visit(team_index,t,sa,itor.base()))
+						return; //< Early abort
+				}
+			}
+			else //forward
+			{
+				side_actions::iterator itor = sa.begin();
+				side_actions::iterator end  = sa.end();
+				for(; itor!=end; ++itor)
+					if(!new_this->visit(team_index,t,sa,itor))
+						return; //< Early abort
+			}
+			if(!new_this->post_visit_team(team_index,t,sa))
+				break; //< Early abort
+		}
+	}
+};
+
 /**
  * Abstract base class for all the visitors (cf GoF Visitor Design Pattern)
  * the whiteboard uses.