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A baby step that worked.

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[SVN r9095]
This commit is contained in:
Dave Abrahams
2001-02-10 23:14:42 +00:00
parent dbb99b1cf3
commit c5f24d0d72
1 changed files with 57 additions and 49 deletions
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106
include/boost/iterator_adaptors.hpp
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@ -390,8 +390,51 @@ namespace detail {
i.policies().decrement(i.iter());
}
# ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
template <bool is_pointer>
struct iterator_defaults_select
{
template <class Iterator,class Value>
struct traits
{
typedef typename boost::detail::iterator_traits<Iterator>::value_type value_type;
typedef typename boost::detail::iterator_traits<Iterator>::pointer pointer;
typedef typename boost::detail::iterator_traits<Iterator>::reference reference;
};
};
template <>
struct iterator_defaults_select<true>
{
template <class Iterator,class Value>
struct traits
{
typedef Value value_type;
typedef Value* pointer;
typedef Value& reference;
};
};
template <class Iterator,class Value>
struct iterator_defaults
{
enum { is_ptr = boost::is_pointer<Iterator>::value };
typedef iterator_defaults_select<is_ptr>::template traits<Iterator,Value> traits;
typedef typename traits::pointer pointer;
typedef typename traits::reference reference;
};
# else
template <class Iterator,class Value>
struct iterator_defaults : iterator_traits<Iterator>
{
typedef typename iterator_traits<Iterator>::pointer pointer;
typedef typename iterator_traits<Iterator>::reference reference;
};
# endif
} // namespace detail
//============================================================================
//iterator_adaptor - Adapts a generic piece of data as an iterator. Adaptation
// is especially easy if the data being adapted is itself an iterator
@ -778,52 +821,10 @@ struct reverse_iterator_policies : public default_iterator_policies
{ return y < x; }
};
#ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
namespace detail {
template <bool is_pointer>
struct iterator_defaults_select
{
template <class Iterator,class Value>
struct traits
{
typedef typename boost::detail::iterator_traits<Iterator>::value_type value_type;
typedef typename boost::detail::iterator_traits<Iterator>::pointer pointer;
typedef typename boost::detail::iterator_traits<Iterator>::reference reference;
};
};
template <>
struct iterator_defaults_select<true>
{
template <class Iterator,class Value>
struct traits
{
typedef Value value_type;
typedef Value* pointer;
typedef Value& reference;
};
};
template <class Iterator,class Value>
struct iterator_defaults
{
enum { is_ptr = boost::is_pointer<Iterator>::value };
typedef iterator_defaults_select<is_ptr>::template traits<Iterator,Value> traits;
typedef typename traits::pointer pointer;
typedef typename traits::reference reference;
};
}
#endif
template <class Iterator,
class Value = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_traits<Iterator>::value_type,
#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
class Pointer = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_traits<Iterator>::pointer,
class Reference = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_traits<Iterator>::reference,
#else
class Pointer = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_defaults<Iterator,Value>::pointer,
class Reference = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_defaults<Iterator,Value>::reference,
#endif
class Category = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_traits<Iterator>::iterator_category,
class Distance = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_traits<Iterator>::difference_type
>
@ -969,25 +970,32 @@ namespace detail {
template <class Iterator>
struct non_bidirectional_category
{
# if !defined(__MWERKS__) || __MWERKS__ > 0x4000
typedef typename reduce_to_base_class<
std::forward_iterator_tag,
typename iterator_traits<Iterator>::iterator_category
>::type type;
private:
// For some reason, putting this assertion in filter_iterator_generator fails inexplicably under MSVC
BOOST_STATIC_ASSERT((!boost::is_convertible<type*, std::bidirectional_iterator_tag*>::value));
# else
// is_convertible doesn't work with MWERKS
typedef typename iterator_traits<Iterator>::iterator_category input_category;
typedef typename if_true<(
boost::is_same<input_category,std::random_access_iterator_tag>::value
|| boost::is_same<input_category,std::bidirectional_iterator_tag>::value
)>::template then<
std::forward_iterator_tag,
input_category
>::type type;
# endif
};
}
template <class Predicate, class Iterator,
class Value = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_traits<Iterator>::value_type,
#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
class Pointer = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_traits<Iterator>::pointer,
class Reference = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_traits<Iterator>::reference,
#else
class Pointer = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_defaults<Iterator,Value>::pointer,
class Reference = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_defaults<Iterator,Value>::reference,
#endif
class Pointer = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_defaults<Iterator,Value>::pointer,
class Category = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::non_bidirectional_category<Iterator>::type,
class Distance = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_traits<Iterator>::difference_type
>