WIP document the concept of the hash ID, get rid of the uggly cast

src/lib/ha-id.hpp

@@ -21,7 +21,27 @@
 */
 
 
-/** @file ha-id.hpp 
+/** @file ha-id.hpp
+ ** A template for generating hash based ID tags carrying compile-time type info.
+ ** While the actual storage is assumed to be based on a POD, the type info is crucial
+ ** to circumvent the problems with an "object" base class. Frequently, the need to
+ ** manage some objects in a central facility drives us to rely on a common base class,
+ ** irrespective of an actual common denominator in the semantics of the objects to
+ ** be managed within this collection. Typically this results in this common base class
+ ** being almost worthless as an API or interface, causing lots of type casts when using
+ ** such a common object management facility. Passing additional context or API information
+ ** on a metaprogramming level through the management interface helps avoiding these 
+ ** shortcomings. 
+ ** 
+ ** Here we build an ID facility with the following properties:
+ ** - based on a configurable storage/implementation of the actual hash or index code.
+ ** - tied to a specific hierarchy of objects (template parameter "BA")
+ ** - providing an additional template parameter to pass the desired type info
+ ** - establishing an type hierarchy relation between ID template instances, such that
+ **   the IDs typed to the derived/specialised objects can stand-in for the generic
+ **   ID typed to the base class.
+ ** - providing a Mixin, which allows any hierarchy to use this facility without 
+ **   much code duplication.
  **
  ** @see HaID_test
  ** @see Placement usage example
@@ -33,32 +53,50 @@
 #ifndef LIB_HA_ID_H
 #define LIB_HA_ID_H
 
-//#include "pre.hpp"
-//#include "proc/mobject/session/locatingpin.hpp"
-//#include "proc/asset/pipe.hpp"
+//#include "lib/util.hpp"
 
 //#include <tr1/memory>
+#include <cstdlib>
 
 
 namespace lib {
 
 //  using std::tr1::shared_ptr;
+  using std::rand;
   
   
-  /** @todo WIP a generic hash-index, maybe also usable for assets */
   struct LuidH 
     {
       long dummy_;
+      
+      LuidH() : dummy_(rand()) {}
     };
   
+  /** 
+   * Generic hash based and hierarchically typed ID
+   * @todo WIP maybe also usable for assets?
+   */
   template<typename T, class BA>
   struct HaID;
   
   template<class BA>
   struct HaIndexed
     {
-      LuidH id_;
-      HaID<BA,BA> const& getID()  const;
+      typedef HaID<BA,BA> RootID;
+      RootID id_;
+      
+      RootID const& getID()  const
+        { 
+          return id_; 
+        }
+      void resetID(HaIndexed const& ref)
+        { 
+          this->id_ = ref.getID();
+        }
+      void resetID(RootID const& ref) ///< @todo this mutator should be removed in the final version to keep the actual hash opaque
+        { 
+          this->id_.dummy_ = ref.dummy_;
+        }
     };
   
   template<class BA>
@@ -75,52 +113,8 @@ namespace lib {
       HaID (T const& ref) : HaID<BA,BA> (ref) {}
     };
   
-  template<class BA>
-  inline HaID<BA,BA> const&
-  HaIndexed<BA>::getID()  const
-  {
-    return *(static_cast<const HaID<BA,BA>*> (&id_));
-  }
-
-  
-  struct Base
-    {
-      int ii_;
-    };
-  
-  struct TestA : Base, HaIndexed<TestA>
-    {
-    };
-  struct TestBA : TestA {};
-  struct TestBB : TestA {};
-
-  
-  
-  /**
-   */
-  class PlacementRef
-    {
-    public:
-      /**
-       * 
-       */
-      class ID
-        {
-        };
-      
-      template<class MO>
-      class IDp : public ID
-        {
-        };
-      
-      
-    };
   
   
   
-  
-  
-
-
 } // namespace lib
 #endif

tests/40components.tests

@@ -215,6 +215,11 @@ out: dtor ~TargetObj(12) successful
 END
 
 
+PLANNED "HaID_test" HaID_test <<END
+return: 0
+END
+
+
 TEST "LifeCycle_test" LifeCycle_test  <<END
 return: 0
 END

tests/lib/ha-id-test.cpp

@@ -22,33 +22,34 @@
 
 
 #include "lib/test/run.hpp"
-//#include "proc/asset/media.hpp"
-//#include "proc/mobject/session.hpp"
-//#include "proc/mobject/session/edl.hpp"
-//#include "proc/mobject/session/testclip.hpp"
+
 #include "lib/ha-id.hpp"
-//#include "proc/mobject/explicitplacement.hpp"
-//#include "lib/util.hpp"
 
-//#include <boost/format.hpp>
-//#include <iostream>
+#include <boost/format.hpp>
+#include <iostream>
 
-//using boost::format;
-//using lumiera::Time;
-//using util::contains;
-using std::string;
-//using std::cout;
+using boost::format;
+//using std::string;
+using std::cout;
 
 
 namespace lib {
 namespace test{
-      
-  /** @todo WIP a generic hash-index, maybe also usable for assets */
-  HaID<TestBB,TestA> hahaBB1;
   
-  TestBA bab;
-  HaID<TestBA,TestA> hahaBA1 (bab);
-  ///////////////////////////////TODO (Experimentation)
+  /* ==  a hierarchy of test-dummy objects to use the HaID == */
+  
+  struct Base
+    {
+      int ii_;
+    };
+  
+  struct TestA : Base, HaIndexed<TestA>
+    {
+    };
+  struct TestBA : TestA {};
+  struct TestBB : TestA {};
+  
+  
   
   
   /***************************************************************************
@@ -61,7 +62,21 @@ namespace test{
       virtual void
       run (Arg) 
         {
+          format fmt ("sizeof( %s ) = %d\n");
+          
           /////////////////////////////////TODO
+          HaID<TestBB,TestA> hahaBB1;
+          
+          TestBA bab;
+          bab.resetID(hahaBB1);
+          
+          HaID<TestBA,TestA> hahaBA1 (bab);
+          
+          cout << fmt % "TestBA"     % sizeof(bab);
+          cout << fmt % "ID<TestBA>" % sizeof(hahaBA1);
+          cout << fmt % "ID<TestBB>" % sizeof(hahaBB1);
+          
+          ASSERT (hahaBA1.dummy_ == hahaBB1.dummy_);
         } 
     };