williamr@2: //  (C) Copyright Jeremy Siek 2004 
williamr@2: //  Distributed under the Boost Software License, Version 1.0. (See
williamr@2: //  accompanying file LICENSE_1_0.txt or copy at
williamr@2: //  http://www.boost.org/LICENSE_1_0.txt)
williamr@2: 
williamr@2: #ifndef BOOST_PROPERTY_HPP
williamr@2: #define BOOST_PROPERTY_HPP
williamr@2: 
williamr@2: #include <boost/pending/ct_if.hpp>
williamr@2: 
williamr@2: namespace boost {
williamr@2: 
williamr@2:   struct no_property { 
williamr@2:     typedef no_property tag_type;
williamr@2:     typedef no_property next_type;
williamr@2:     typedef no_property value_type;
williamr@2:     enum { num = 0 };
williamr@2:     typedef void kind;
williamr@2:   };
williamr@2: 
williamr@2:   template <class Tag, class T, class Base = no_property>
williamr@2:   struct property : public Base {
williamr@2:     typedef Base next_type;
williamr@2:     typedef Tag tag_type;
williamr@2:     typedef T value_type;
williamr@2: #if BOOST_WORKAROUND (__GNUC__, < 3)
williamr@2:     property() { }
williamr@2: #else
williamr@2:     property() : m_value() { }
williamr@2: #endif
williamr@2:     property(const T& v) : m_value(v) { }
williamr@2:     property(const T& v, const Base& b) : Base(b), m_value(v) { }
williamr@2:     // copy constructor and assignment operator will be generated by compiler
williamr@2: 
williamr@2:     T m_value;
williamr@2:   };
williamr@2: 
williamr@2:   // The BGL properties specialize property_kind and
williamr@2:   // property_num, and use enum's for the Property type (see
williamr@2:   // graph/properties.hpp), but the user may want to use a class
williamr@2:   // instead with a nested kind type and num.  Also, we may want to
williamr@2:   // switch BGL back to using class types for properties at some point.
williamr@2: 
williamr@2:   template <class PropertyTag>
williamr@2:   struct property_kind {
williamr@2:     typedef typename PropertyTag::kind type;
williamr@2:   };
williamr@2: 
williamr@2:   template <class P>
williamr@2:   struct has_property { 
williamr@2:     BOOST_STATIC_CONSTANT(bool, value = true);
williamr@2:     typedef true_type type;
williamr@2:   };
williamr@2:   template <>
williamr@2:   struct has_property<no_property> { 
williamr@2:     BOOST_STATIC_CONSTANT(bool, value = false); 
williamr@2:     typedef false_type type; 
williamr@2:   };
williamr@2: 
williamr@2: } // namespace boost
williamr@2: 
williamr@2: #include <boost/pending/detail/property.hpp>
williamr@2: 
williamr@2: namespace boost {
williamr@2: 
williamr@2:   template <class PropertyList, class Tag>
williamr@2:   struct property_value {
williamr@2: #if !defined BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
williamr@2:     typedef typename detail::build_property_tag_value_alist<PropertyList>::type AList;
williamr@2:     typedef typename detail::extract_value<AList,Tag>::type type;
williamr@2: #else
williamr@2:     typedef typename detail::build_property_tag_value_alist<PropertyList>::type AList;
williamr@2:     typedef typename detail::ev_selector<AList>::type Extractor;
williamr@2:     typedef typename Extractor::template bind_<AList,Tag>::type type;
williamr@2: #endif  
williamr@2:   };
williamr@2: 
williamr@2:   template <class Tag1, class Tag2, class T1, class Base>
williamr@2:   inline typename property_value<property<Tag1,T1,Base>, Tag2>::type& 
williamr@2:   get_property_value(property<Tag1,T1,Base>& p, Tag2 tag2) {
williamr@2:     BOOST_STATIC_CONSTANT(bool, 
williamr@2:                           match = (detail::same_property<Tag1,Tag2>::value));
williamr@2:     typedef property<Tag1,T1,Base> Prop;
williamr@2:     typedef typename property_value<Prop, Tag2>::type T2;
williamr@2:     T2* t2 = 0;
williamr@2:     typedef detail::property_value_dispatch<match> Dispatcher;
williamr@2:     return Dispatcher::get_value(p, t2, tag2);
williamr@2:   }
williamr@2:   template <class Tag1, class Tag2, class T1, class Base>
williamr@2:   inline
williamr@2:   const typename property_value<property<Tag1,T1,Base>, Tag2>::type& 
williamr@2:   get_property_value(const property<Tag1,T1,Base>& p, Tag2 tag2) {
williamr@2:     BOOST_STATIC_CONSTANT(bool, 
williamr@2:                           match = (detail::same_property<Tag1,Tag2>::value));
williamr@2:     typedef property<Tag1,T1,Base> Prop;
williamr@2:     typedef typename property_value<Prop, Tag2>::type T2;
williamr@2:     T2* t2 = 0;
williamr@2:     typedef detail::property_value_dispatch<match> Dispatcher;
williamr@2:     return Dispatcher::const_get_value(p, t2, tag2);
williamr@2:   }
williamr@2: 
williamr@2:  namespace detail {
williamr@2: #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
williamr@2:    template<typename FinalTag, typename FinalType>
williamr@2:    struct retag_property_list
williamr@2:    {
williamr@2:      typedef property<FinalTag, FinalType> type;
williamr@2:      typedef FinalType retagged;
williamr@2:    };
williamr@2: 
williamr@2:    template<typename FinalTag, typename Tag, typename T, typename Base>
williamr@2:    struct retag_property_list<FinalTag, property<Tag, T, Base> >
williamr@2:    {
williamr@2:    private:
williamr@2:      typedef retag_property_list<FinalTag, Base> next;
williamr@2: 
williamr@2:    public:
williamr@2:      typedef property<Tag, T, typename next::type> type;
williamr@2:      typedef typename next::retagged retagged;
williamr@2:    };
williamr@2: 
williamr@2:    template<typename FinalTag>
williamr@2:    struct retag_property_list<FinalTag, no_property>
williamr@2:    {
williamr@2:      typedef no_property type;
williamr@2:      typedef no_property retagged;
williamr@2:    };
williamr@2: #endif
williamr@2:   }
williamr@2: } // namesapce boost
williamr@2: 
williamr@2: #endif /* BOOST_PROPERTY_HPP */