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[SVN r21519]
This commit is contained in:
Thomas Witt
2004-01-06 19:37:17 +00:00
parent 20b31d1cca
commit fb1fc6f909
3 changed files with 378 additions and 21 deletions
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140
include/boost/iterator/iterator_facade.hpp
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@ -63,6 +63,72 @@ namespace boost
#endif
};
//
// Determines the iterator type that can be
// safely used to implement binary operators
//
template <
class Facade1,
class Facade2
>
struct interoperable_base
: mpl::if_<
is_convertible<Facade1, Facade2>
, Facade2
, Facade1
>
{
};
template <class Facade1, class Facade2>
struct difference_type
{
typedef typename interoperable_base<Facade1, Facade2>::type::difference_type type;
};
template <class Facade1, class Facade2>
bool equal(Facade1 const&, Facade2 const&);
template <class Facade1, class Facade2>
typename Facade1::difference_type distance_to(Facade1 const&, Facade2 const&);
template <bool UseLhsMember>
struct facade_binary_operator
{
template <class Facade1, class Facade2>
static bool equal(Facade1 const& lhs,
Facade2 const& rhs)
{
return ::boost::detail::equal(lhs, rhs);
}
template <class Facade1, class Facade2>
static typename Facade1::difference_type distance_to(Facade1 const& lhs,
Facade2 const& rhs)
{
return ::boost::detail::distance_to(lhs, rhs);
}
};
template <>
struct facade_binary_operator<false>
{
template <class Facade1, class Facade2>
static bool equal(Facade1 const& lhs,
Facade2 const& rhs)
{
return ::boost::detail::equal(rhs, lhs);
}
template <class Facade1, class Facade2>
static typename Facade2::difference_type distance_to(Facade1 const& lhs,
Facade2 const& rhs)
{
return -::boost::detail::distance_to(rhs, lhs);
}
};
//
// Generates associated types for an iterator_facade with the
// given parameters.
@ -256,9 +322,11 @@ namespace boost
BOOST_ITERATOR_FACADE_RELATION(>=)
# undef BOOST_ITERATOR_FACADE_RELATION
BOOST_ITERATOR_FACADE_INTEROP_HEAD(
friend, -, typename Derived1::difference_type)
;
template < class Derived1, class V1, class TC1, class R1, class D1 , class Derived2, class V2, class TC2, class R2, class D2 > friend typename detail::enable_if_interoperable< Derived1, Derived2, typename std::iterator_traits<typename detail::interoperable_base<Derived1, Derived2> ::type > ::difference_type > ::type operator -( iterator_facade<Derived1, V1, TC1, R1, D1> const& lhs , iterator_facade<Derived2, V2, TC2, R2, D2> const& rhs);
// BOOST_ITERATOR_FACADE_INTEROP_HEAD(
// friend, -, (typename std::iterator_traits<typename detail::interoperable_base<Derived1, Derived2>::type >::difference_type))
// ;
BOOST_ITERATOR_FACADE_PLUS_HEAD(
friend
@ -297,7 +365,7 @@ namespace boost
template <class Facade1, class Facade2>
static bool equal(Facade1 const& f1, Facade2 const& f2)
{
return f1.equal(f2);
return detail::facade_binary_operator< is_convertible< Facade2, Facade1 >::value >::equal(f1, f2);
}
template <class Facade>
@ -307,17 +375,51 @@ namespace boost
}
template <class Facade1, class Facade2>
static typename Facade1::difference_type distance_to(
static typename detail::difference_type<Facade1, Facade2>::type distance_to(
Facade1 const& f1, Facade2 const& f2)
{
return f1.distance_to(f2);
return detail::facade_binary_operator< is_convertible< Facade2, Facade1 >::value >::distance_to(f1, f2);
}
private:
// objects of this class are useless
iterator_core_access(); //undefined
// We would need template friends for these to be private
public:
template <class Facade1, class Facade2>
static bool equal_fwd(Facade1 const& f1, Facade2 const& f2)
{
return f1.equal(f2);
}
template <class Facade1, class Facade2>
static typename Facade1::difference_type distance_to_fwd(
Facade1 const& f1, Facade2 const& f2)
{
return f1.distance_to(f2);
}
};
namespace detail
{
template <class Facade1, class Facade2>
bool equal(Facade1 const& f1, Facade2 const& f2)
{
return iterator_core_access::equal_fwd(f1, f2);
}
template <class Facade1, class Facade2>
typename Facade1::difference_type distance_to(Facade1 const& f1, Facade2 const& f2)
{
return iterator_core_access::distance_to_fwd(f1, f2);
}
}
//
// iterator_facade - use as a public base class for defining new
// standard-conforming iterators.
@ -550,19 +652,25 @@ namespace boost
BOOST_ITERATOR_FACADE_RELATION(>=, return 0 <=, distance_to)
# undef BOOST_ITERATOR_FACADE_RELATION
// operator- requires an additional part in the static assertion
BOOST_ITERATOR_FACADE_INTEROP(
-
, typename Derived1::difference_type
, (is_same<
BOOST_DEDUCED_TYPENAME Derived1::difference_type
, BOOST_DEDUCED_TYPENAME Derived2::difference_type
>::value)
, return
, distance_to )
// // operator- requires an additional part in the static assertion
// BOOST_ITERATOR_FACADE_INTEROP(
// -
// , typename Derived1::difference_type
// , (is_same<
// BOOST_DEDUCED_TYPENAME Derived1::difference_type
// , BOOST_DEDUCED_TYPENAME Derived2::difference_type
// >::value)
// , return
// , distance_to )
# undef BOOST_ITERATOR_FACADE_INTEROP
# undef BOOST_ITERATOR_FACADE_INTEROP_HEAD
template < class Derived1, class V1, class TC1, class R1, class D1 , class Derived2, class V2, class TC2, class R2, class D2 > typename detail::enable_if_interoperable< Derived1, Derived2, typename std::iterator_traits<typename detail::interoperable_base<Derived1, Derived2> ::type > ::difference_type > ::type operator -( iterator_facade<Derived1, V1, TC1, R1, D1> const& lhs , iterator_facade<Derived2, V2, TC2, R2, D2> const& rhs)
{
return iterator_core_access::distance_to(static_cast<Derived2 const&>(rhs), static_cast<Derived1 const&>(lhs));
}
# define BOOST_ITERATOR_FACADE_PLUS(args) \
BOOST_ITERATOR_FACADE_PLUS_HEAD(inline, args) \
{ \