RE: [boost] Wave/flex_string with VC7.0 + dinkumware (new problem)

From: Reece Dunn (msclrhd_at_[hidden])
Date: 2004-05-21 10:43:15

Hartmut Kaiser wrote:
>Reece Dunn wrote:
>
> > I reported that VC7 uses the correct implementation of
> > reverse_iterator, and that this can be detected via
> > BOOST_NO_STD_ITERATOR. Although this compiles, you cannot use
> > reverse iterators.
> >
> > The problem is that the iterator is of the form (const) T *,
> > and this fails because there is not a correct implementation
> > of iterator_traits (due to a lack of partial template
> > specialization) that *is* detected by BOOST_NO_STD_ITERATOR_TRAITS.
> >
> > The solution would therefore be to - in this case - provide
> > an iterator wrapper around a standard pointer so it has the
> > correct Iter::value_type, etc definitions. Is there an
> > iterator_adaptor that provides this within boost? If not,
> > should there be one? I am looking into this and will commit
> > the solution to my iterator_adaptor-style implementation
> > (sandbox/boost/fixed_string/detail/basic_string_impl.hpp).
> >
> > NOTE: If you want to add any of my modifications to the Wave
> > flex_string implementation, feel free, but be warned that I
> > haven't run full tests on it yet and thus there might be bugs
> > in it (especially the pod_xxx --> traits_type::xxx, since
> > these functions have different parameters).
>
>Thanks again for pointing that out. I'll have a look at it next week, when
>I'm back home. Is this problem specific for VC7 or does it occur on the
>VC7.1 platform also? If it's specific, then I would some need from somebody
>to fix this, because I don't have it handy to reproduce the problem. Could
>you provide a fix for Wave then?

It is just a VC 7 problem, because VC 7 does not have partial template 
specialization.

I have a fix now for this: replace std::reverse_iterator< Iterator > with 
boost::reverse_iterator< Iterator > (I do not have a proper diff):

+#  include <boost/iterator/reverse_iterator.hpp>

// ...

-    typedef std::reverse_iterator<iterator
-#ifdef BOOST_NO_STD_ITERATOR_TRAITS
-    , value_type
-#endif
-    > reverse_iterator;
+   typedef boost::reverse_iterator< iterator > reverse_iterator;

-    typedef std::reverse_iterator<const_iterator
-#ifdef BOOST_NO_STD_ITERATOR_TRAITS
-    , const value_type
-#endif
-    > const_reverse_iterator;
+   typedef boost::reverse_iterator< const_iterator > 
const_reverse_iterator;

I have this in my implementation if you want to take a look, along with 
several other changes to the flex_string implementation.

Regards,
Reece

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