merged from trunk

[SVN r21580]

include/boost/pointee.hpp

@@ -9,7 +9,9 @@
 
 # include <boost/detail/is_incrementable.hpp>
 # include <boost/iterator/iterator_traits.hpp>
+# include <boost/type_traits/add_const.hpp>
 # include <boost/type_traits/remove_cv.hpp>
+# include <boost/mpl/if.hpp>
 # include <boost/mpl/apply_if.hpp>
 
 namespace boost { 
@@ -17,9 +19,37 @@ namespace boost {
 namespace detail
 {
   template <class P>
-  struct smart_ptr_value
+  struct smart_ptr_pointee
   {
-      typedef typename remove_cv<typename P::element_type>::type type;
+      typedef typename P::element_type type;
+  };
+
+  template <class Iterator>
+  struct iterator_pointee
+  {
+      typedef typename iterator_traits<Iterator>::value_type value_type;
+      
+      struct impl
+      {
+          template <class T>
+          static char test(T const&);
+          
+          static char (& test(value_type&) )[2];
+          
+          static Iterator& x;
+      };
+      
+      BOOST_STATIC_CONSTANT(bool, is_constant = sizeof(impl::test(*impl::x)) == 1);
+      
+      typedef typename mpl::if_c<
+#  if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551))
+          ::boost::detail::iterator_pointee<Iterator>::is_constant
+#  else
+          is_constant
+#  endif 
+        , typename add_const<value_type>::type
+        , value_type
+      >::type type;
   };
 }
 
@@ -27,11 +57,11 @@ template <class P>
 struct pointee
 {
     typedef typename remove_cv<P>::type stripped;
-    
+
     typedef typename mpl::apply_if<
         detail::is_incrementable<stripped>
-      , iterator_value<stripped>
-      , detail::smart_ptr_value<stripped>
+      , detail::iterator_pointee<stripped>
+      , detail::smart_ptr_pointee<stripped>
     >::type type;
 };