add template parameter for the reference.

[[Imported from SVN: r5345]]

common/genericiterator.hh

@@ -55,7 +55,6 @@ namespace Dune {
         return values_[i];
       }
 
-
       const T& operator[](int i) const{
         return values_[i];
       }
@@ -87,12 +86,12 @@ namespace Dune {
    * If template parameter C has a const qualifier we are a const iterator, otherwise we
    * are a mutable iterator.
    */
-  template<class C, class T, class D = std::ptrdiff_t>
+  template<typename C, typename T, typename R = T&, typename D = std::ptrdiff_t>
   class GenericIterator :
-    public Dune::RandomAccessIteratorFacade<GenericIterator<C,T>,T, T&, D>
+    public Dune::RandomAccessIteratorFacade<GenericIterator<C,T>,T, R, D>
   {
-    friend class GenericIterator<typename remove_const<C>::type, typename remove_const<T>::type >;
-    friend class GenericIterator<const typename remove_const<C>::type, const typename remove_const<T>::type >;
+    friend class GenericIterator<typename remove_const<C>::type, typename remove_const<T>::type, R, D>;
+    friend class GenericIterator<const typename remove_const<C>::type, const typename remove_const<T>::type, R, D>;
 
   public:
 
@@ -118,6 +117,11 @@ namespace Dune {
      */
     typedef D DifferenceType;
 
+    /**
+     * @brief The type of the reference to the values accessed.
+     */
+    typedef R Reference;
+
     // Constructors needed by the base iterators.
     GenericIterator() : container_(0), position_(0)
     {}
@@ -140,7 +144,7 @@ namespace Dune {
      * 1. if we are mutable this is the only valid copy constructor, as the arguments is a mutable iterator
      * 2. if we are a const iterator the argument is a mutable iterator => This is the needed conversion to initialize a const iterator form a mutable one.
      */
-    GenericIterator(const GenericIterator<typename remove_const<Container>::type, typename remove_const<T>::type,D >& other) : container_(other.container_), position_(other.position_)
+    GenericIterator(const GenericIterator<typename remove_const<Container>::type, typename remove_const<T>::type,R,D>& other) : container_(other.container_), position_(other.position_)
     {}
 
     /**
@@ -152,22 +156,22 @@ namespace Dune {
      * 1. if we are mutable the arguments is a const iterator and therefore calling this method is mistake in the users code and results in a (probably not understandable compiler error
      * 2. If we are a const iterator this is the default copy constructor as the argument is a const iterator too.
      */
-    GenericIterator(const GenericIterator<const typename remove_const<Container>::type, const typename remove_const<T>::type, D >& other) : container_(other.container_), position_(other.position_)
+    GenericIterator(const GenericIterator<const typename remove_const<Container>::type, const typename remove_const<T>::type,R,D>& other) : container_(other.container_), position_(other.position_)
     {}
 
     // Methods needed by the forward iterator
-    bool equals(const GenericIterator<typename remove_const<Container>::type,typename remove_const<T>::type,D>& other) const
+    bool equals(const GenericIterator<typename remove_const<Container>::type,typename remove_const<T>::type,R,D>& other) const
     {
       return position_ == other.position_ && container_ == other.container_;
     }
 
 
-    bool equals(const GenericIterator<const typename remove_const<Container>::type,const typename remove_const<T>::type,D>& other) const
+    bool equals(const GenericIterator<const typename remove_const<Container>::type,const typename remove_const<T>::type,R,D>& other) const
     {
       return position_ == other.position_ && container_ == other.container_;
     }
 
-    T& dereference() const {
+    Reference dereference() const {
       return container_->operator[](position_);
     }
 
@@ -181,7 +185,7 @@ namespace Dune {
     }
 
     // Additional function needed by RandomAccessIterator
-    T& elementAt(DifferenceType i) const {
+    Reference elementAt(DifferenceType i) const {
       return container_->operator[](position_+i);
     }
 
@@ -189,13 +193,13 @@ namespace Dune {
       position_=position_+n;
     }
 
-    std::ptrdiff_t distanceTo(GenericIterator<const typename remove_const<Container>::type,const typename remove_const<T>::type,D> other) const
+    DifferenceType distanceTo(GenericIterator<const typename remove_const<Container>::type,const typename remove_const<T>::type,R,D> other) const
     {
       assert(other.container_==container_);
       return other.position_ - position_;
     }
 
-    std::ptrdiff_t distanceTo(GenericIterator<typename remove_const<Container>::type, typename remove_const<T>::type,D> other) const
+    DifferenceType distanceTo(GenericIterator<typename remove_const<Container>::type, typename remove_const<T>::type,R,D> other) const
     {
       assert(other.container_==container_);
       return other.position_ - position_;