boostorg/iterator
1
0
Fork 1
mirror of https://github.com/boostorg/iterator.git synced 2025-07-29 12:27:33 +02:00
Code Issues Packages Projects Releases Wiki Activity

Improved interface to indirect_ and reverse_ iterators

Browse Source 
[SVN r9065]
This commit is contained in:
Dave Abrahams
2001-02-10 00:26:55 +00:00
parent 6f90982a45
commit 15b5b66776
1 changed files with 121 additions and 38 deletions
Download Patch File Download Diff File Expand all files Collapse all files

159
include/boost/iterator_adaptors.hpp
View File

@ -13,6 +13,8 @@
// Revision History:
// 09 Feb 2001 David Abrahams
// Improved interface to indirect_ and reverse_ iterators
//
// Rolled back Jeremy's new constructor for now; it was causing
// problems with counting_iterator_test
//
@ -658,39 +660,77 @@ 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
} template <class T> struct undefined; namespace boost {
namespace detail {
# if !defined(BOOST_MSVC) // stragely instantiated even when unused! Maybe try a recursive template someday ;-)
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;
};
# 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
#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;
typedef typename boost::remove_const<Value>::type value_type;
typedef Pointer pointer;
typedef Reference reference;
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
#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
// Tried to allow InnerTraits to be provided by explicit template
// argument to the function, but could not get it to work. -Jeremy Siek
template <class Value, class OuterIterator>
inline typename indirect_iterator_generator<OuterIterator,Value>::type
make_indirect_iterator(OuterIterator base, Value* = 0)
{
typedef typename indirect_iterator_generator
<OuterIterator, Value>::type result_t;
return result_t(base);
}
# if 0 // This just doesn't seem to work under any circumstances!
template <class OuterIterator>
inline typename indirect_iterator_generator<OuterIterator>::type
make_indirect_iterator(OuterIterator base)
@ -699,18 +739,7 @@ make_indirect_iterator(OuterIterator base)
<OuterIterator>::type result_t;
return result_t(base);
}
#endif
// Tried to allow InnerTraits to be provided by explicit template
// argument to the function, but could not get it to work. -Jeremy Siek
template <class InnerTraits, class OuterIterator>
inline typename indirect_iterator_generator<OuterIterator, InnerTraits>::type
make_indirect_iterator(OuterIterator base, InnerTraits)
{
typedef typename indirect_iterator_generator
<OuterIterator, InnerTraits>::type result_t;
return result_t(base);
}
# endif
//=============================================================================
@ -757,10 +786,6 @@ struct reverse_iterator_generator
Traits> type;
};
// WARNING: Do not use the one template parameter version of
// make_reverse_iterator() if the iterator is a builtin pointer type
// and if your compiler does not support partial specialization.
template <class Iterator>
inline typename reverse_iterator_generator<Iterator>::type
make_reverse_iterator(Iterator base)
@ -769,17 +794,73 @@ make_reverse_iterator(Iterator base)
return result_t(base);
}
// Specify Traits type with an explicit argument,
// i.e., make_reverse_iterator<Traits>(base)
template <class T> struct undefined;
template <class Traits, class Iterator>
inline typename reverse_iterator_generator<Iterator, Traits>::type
make_reverse_iterator(Iterator base, Traits* = 0)
#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
>
struct reverse_iterator_generator2
{
typedef typename reverse_iterator_generator<Iterator, Traits>::type result_t;
typedef typename boost::remove_const<Value>::type value_type;
typedef typename boost::iterator<Category,value_type,Distance,Pointer,Reference> traits;
typedef iterator_adaptor<Iterator,reverse_iterator_policies,traits> type;
};
//#ifndef BOOST_MSVC
template <class Iterator>
inline typename reverse_iterator_generator2<Iterator>::type
make_reverse_iterator2(Iterator base)
{
typedef typename reverse_iterator_generator2<Iterator>::type result_t;
return result_t(base);
}
//#endif
//=============================================================================
// Projection Iterators Adaptor
@ -929,6 +1010,8 @@ make_filter_iterator(Iterator first, Iterator last, const Predicate& p = Predica
} // namespace boost
# undef BOOST_ARG_DEPENDENT_TYPENAME
#endif