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https://github.com/boostorg/iterator.git
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first stab at simplified version
[SVN r21482]
This commit is contained in:
Jeremy Siek
@ -37,63 +37,8 @@ namespace boost
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template <class Iter, class Value, class Category, class Reference, class Difference>
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class indirect_iterator;
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template <class T>
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struct referent;
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namespace detail
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{
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struct unspecified {};
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//
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// Detection for whether a type has a nested `element_type'
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// typedef. Used to detect smart pointers. For compilers not
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// supporting mpl's has_xxx, we supply specializations. However, we
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// really ought to have a specializable is_pointer template which
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// can be used instead with something like
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// boost/python/pointee.hpp to find the value_type.
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//
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# ifndef BOOST_MPL_NO_AUX_HAS_XXX
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namespace aux
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{
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BOOST_MPL_HAS_XXX_TRAIT_DEF(element_type)
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BOOST_MPL_HAS_XXX_TRAIT_DEF(type)
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}
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template <class T>
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struct has_element_type
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: mpl::bool_<
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mpl::if_<
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is_class<T>
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, ::boost::detail::aux::has_element_type<T>
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, mpl::false_
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>::type::value
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>
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{
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};
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# else
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template <class T>
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struct has_element_type
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: mpl::false_ {};
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template <class T>
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struct has_element_type<boost::shared_ptr<T> >
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: mpl::true_ {};
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template <class T>
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struct has_element_type<boost::scoped_ptr<T> >
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: mpl::true_ {};
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template <class T>
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struct has_element_type<std::auto_ptr<T> >
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: mpl::true_ {};
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# endif
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// Metafunction accessing the nested ::element_type
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template <class T>
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struct element_type
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: mpl::identity<typename T::element_type>
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{};
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template <class T>
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struct iterator_is_mutable
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: mpl::not_<
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@ -104,65 +49,31 @@ namespace boost
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{
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};
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template <class T>
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struct not_int_impl
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{
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template <class U>
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struct apply {
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typedef T type;
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};
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};
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template <>
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struct not_int_impl<int> {};
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template <class T, class U>
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struct not_int
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: not_int_impl<T>::template apply<U> {};
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template <class Dereferenceable>
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struct class_has_element_type
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: mpl::and_<
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is_class<Dereferenceable>
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, has_element_type<Dereferenceable>
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>
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{};
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// If the Value parameter is unspecified, we use this metafunction
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// to deduce the default types
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// to deduce the default type
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template <class Dereferenceable>
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struct default_indirect_value
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{
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#if 0
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typedef typename remove_cv<
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typename referent<Dereferenceable>::type
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>::type referent_t;
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typedef typename mpl::if_<
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mpl::or_<
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class_has_element_type<Dereferenceable>
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, iterator_is_mutable<Dereferenceable> // This doesn't work when Dereferencable is not an iterator. -JGS
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>
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, referent_t
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, referent_t const
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>::type type;
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#else
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template <class D>
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struct get_from_iter {
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typedef typename mpl::if_<
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iterator_is_mutable<Dereferenceable>
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, typename iterator_value<Dereferenceable>::type
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, typename iterator_value<Dereferenceable>::type const
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>::type type;
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};
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, typename iterator_value<Dereferenceable>::type
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, typename iterator_value<Dereferenceable>::type const
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>::type type;
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};
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typedef typename mpl::apply_if<
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aux::has_type< referent<Dereferenceable> >
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, referent<Dereferenceable>
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, get_from_iter<Dereferenceable>
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>::type type;
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#endif
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// If the Reference parameter is unspecified, we use this metafunction
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// to deduce the default type
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template <class Dereferenceable, class Value>
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struct default_indirect_reference
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{
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struct use_value_ref { typedef Value& type; };
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typedef typename
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mpl::apply_if<
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is_same<Value, use_default>
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, iterator_reference<Dereferenceable>
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, use_value_ref
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>::type type;
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};
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template <class Iter, class Value, class Category, class Reference, class Difference>
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@ -177,7 +88,9 @@ namespace boost
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Value, default_indirect_value<dereferenceable>
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>::type
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, Category
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, Reference
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, typename ia_dflt_help<
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Reference, default_indirect_reference<dereferenceable, Value>
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>::type
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, Difference
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> type;
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};
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@ -186,34 +99,6 @@ namespace boost
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struct indirect_base<int, int, int, int, int> {};
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} // namespace detail
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// User-specializable metafunction which returns the referent of a
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// dereferenceable type. The default implementation returns
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// Dereferenceable::element_type if such a member exists (thus
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// handling the boost smart pointers and auto_ptr), and
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// iterator_traits<Dereferenceable>::value_type otherwise.
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#if 0
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template <class Dereferenceable>
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struct referent
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: mpl::apply_if<
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detail::class_has_element_type<Dereferenceable>
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, detail::element_type<Dereferenceable>
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, iterator_value<Dereferenceable>
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>
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{};
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#else
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namespace detail {
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struct has_no_type { };
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}
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template <class Dereferenceable>
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struct referent
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: mpl::if_<
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detail::class_has_element_type<Dereferenceable>
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, detail::element_type<Dereferenceable>
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, detail::has_no_type
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>::type
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{};
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#endif
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template <
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class Iterator
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