[Iterators] Add IteratorRange helper class

IteratorRange is a cheap, throwaway container to implement support for
range-based for loops if the underlying containers doesn't provide
standard begin() / end () methods.

dune/common/CMakeLists.txt

@@ -62,6 +62,7 @@ install(FILES
         interfaces.hh
         ios_state.hh
         iteratorfacades.hh
+        iteratorrange.hh
         lcm.hh
         lru.hh
         mallocallocator.hh

dune/common/Makefile.am

@@ -58,6 +58,7 @@ commoninclude_HEADERS = 			\
 	interfaces.hh				\
 	ios_state.hh				\
 	iteratorfacades.hh			\
+	iteratorrange.hh			\
 	lcm.hh					\
 	lru.hh					\
 	mallocallocator.hh			\

dune/common/iteratorrange.hh

+// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+// vi: set et ts=4 sw=2 sts=2:
+#ifndef DUNE_COMMON_ITERATORRANGE_HH
+#define DUNE_COMMON_ITERATORRANGE_HH
+
+namespace Dune {
+
+  //! Simple range between a begin and an end iterator.
+  /**
+   * IteratorRange is mainly useful as a lightweight adaptor
+   * class when adding support for range-based for loops to
+   * existing containers that lack a standard begin(), end()
+   * pair of member functions.
+   *
+   * \tparam Iterator  The type of iterator
+   */
+  template<typename Iterator>
+  class IteratorRange
+  {
+
+  public:
+
+    //! The iterator belonging to this range.
+    typedef Iterator iterator;
+
+    //! Constructs an iterator range on [begin,end).
+    IteratorRange(const Iterator& begin, const Iterator& end)
+      : _begin(begin)
+      , _end(end)
+    {}
+
+    //! Returns an iterator pointing to the begin of the range.
+    iterator begin() const
+    {
+      return _begin;
+    }
+
+    //! Returns an iterator pointing past the end of the range.
+    iterator end() const
+    {
+      return _end;
+    }
+
+  private:
+
+    const Iterator _begin;
+    const Iterator _end;
+
+  };
+
+}
+
+#endif // DUNE_COMMON_ITERATORRANGE_HH