try a better interface to indirect iterators

[SVN r9060]
This commit is contained in:
Dave Abrahams
2001-02-09 19:26:19 +00:00
parent 5bfc03ed4a
commit bfda34e9e0

View File

@ -658,39 +658,100 @@ struct indirect_iterator_policies : public default_iterator_policies
{ return **x; }
};
// This macro definition is only temporary in this file
# if !defined(BOOST_MSVC)
# define BOOST_ARG_DEPENDENT_TYPENAME typename
# else
# define BOOST_ARG_DEPENDENT_TYPENAME
# endif
namespace detail {
#if !defined(BOOST_MSVC)
template <class T>
struct value_type_of_value_type {
typedef typename boost::detail::iterator_traits<T>::value_type outer_value;
typedef typename boost::detail::iterator_traits<outer_value>::value_type type;
};
#else // Even this workaround doesn't fly :(
template <class Value>
struct inner_traits_select {
template <class Iter,class Pointer, class Reference>
struct rebind {
struct traits {
typedef typename boost::remove_const<Value>::type value_type;
typedef Pointer pointer;
typedef Reference reference;
};
};
};
struct no_value_type {};
template <>
struct inner_traits_select<no_value_type> {
template <class Iter,class Pointer, class Reference>
struct rebind {
typedef typename boost::detail::iterator_traits<Iter>::value_type outer_value;
typedef typename boost::detail::iterator_traits<outer_value> traits;
};
};
#endif
}
template <class OuterIterator, // Mutable or Immutable, does not matter
// Mutable reference and pointer type in traits class -> mutable indirect iterator;
// Immutable reference and pointer type in traits class -> immutable indirect iterator
class InnerTraits = boost::detail::iterator_traits<typename boost::detail::iterator_traits<OuterIterator>::value_type>
class Value =
#if !defined(BOOST_MSVC)
BOOST_ARG_DEPENDENT_TYPENAME detail::value_type_of_value_type<OuterIterator>::type,
#else
detail::no_value_type,
#endif
class Pointer = Value*,
class Reference = Value&
>
class indirect_iterator_generator
{
typedef boost::detail::iterator_traits<OuterIterator> OuterTraits;
typedef typename OuterTraits::difference_type difference_type;
typedef typename OuterTraits::iterator_category iterator_category;
typedef boost::detail::iterator_traits<OuterIterator> outer_traits;
typedef typename outer_traits::difference_type difference_type;
typedef typename outer_traits::iterator_category iterator_category;
typedef typename InnerTraits::value_type value_type;
typedef typename InnerTraits::pointer pointer;
typedef typename InnerTraits::reference reference;
#if !defined(BOOST_MSVC)
typedef typename boost::remove_const<Value>::type value_type;
typedef Pointer pointer;
typedef Reference reference;
#else
typedef detail::inner_traits_select<Value>::template
rebind<OuterIterator,Pointer,Reference> inner_traits;
typedef typename inner_traits::value_type value_type;
typedef typename inner_traits::pointer pointer;
typedef typename inner_traits::reference reference;
#endif
public:
typedef boost::iterator<iterator_category, value_type, difference_type, pointer, reference> indirect_traits;
typedef iterator_adaptor<OuterIterator, indirect_iterator_policies, indirect_traits> type;
};
template <class OuterIterator, // Mutable or Immutable, does not matter
class ConstInnerIterator, // Immutable
class ConstInnerTraits = boost::detail::iterator_traits<ConstInnerIterator>,
class InnerTraits = boost::detail::iterator_traits<typename boost::detail::iterator_traits<OuterIterator>::value_type>
class Value =
#if !defined(BOOST_MSVC)
BOOST_ARG_DEPENDENT_TYPENAME detail::value_type_of_value_type<OuterIterator>::type,
#else
detail::no_value_type,
#endif
class Pointer = Value*,
class Reference = Value&,
class ConstPointer = const Value*,
class ConstReference = const Value&
>
struct indirect_iterator_pair_generator
{
typedef typename indirect_iterator_generator<OuterIterator,
InnerTraits>::type iterator;
Value, Pointer, Reference>::type iterator;
typedef typename indirect_iterator_generator<OuterIterator,
ConstInnerTraits>::type const_iterator;
Value, ConstPointer, ConstReference>::type const_iterator;
};
#ifndef BOOST_NO_STD_ITERATOR_TRAITS
# undef BOOST_ARG_DEPENDENT_TYPENAME
# ifndef BOOST_NO_STD_ITERATOR_TRAITS
template <class OuterIterator>
inline typename indirect_iterator_generator<OuterIterator>::type
make_indirect_iterator(OuterIterator base)
@ -699,7 +760,7 @@ make_indirect_iterator(OuterIterator base)
<OuterIterator>::type result_t;
return result_t(base);
}
#endif
# endif
// Tried to allow InnerTraits to be provided by explicit template
// argument to the function, but could not get it to work. -Jeremy Siek