//  (C) Copyright Jeremy Siek 2004 

//  Distributed under the Boost Software License, Version 1.0. (See

//  accompanying file LICENSE_1_0.txt or copy at

//  http://www.boost.org/LICENSE_1_0.txt)

#ifndef BOOST_PROPERTY_HPP

#define BOOST_PROPERTY_HPP

#include <boost/pending/ct_if.hpp>

namespace boost {

  struct no_property { 

    typedef no_property tag_type;

    typedef no_property next_type;

    typedef no_property value_type;

    enum { num = 0 };

    typedef void kind;

  };

  template <class Tag, class T, class Base = no_property>

  struct property : public Base {

    typedef Base next_type;

    typedef Tag tag_type;

    typedef T value_type;

#if BOOST_WORKAROUND (__GNUC__, < 3)

    property() { }

#else

    property() : m_value() { }

#endif

    property(const T& v) : m_value(v) { }

    property(const T& v, const Base& b) : Base(b), m_value(v) { }

    // copy constructor and assignment operator will be generated by compiler

    T m_value;

  };

  // The BGL properties specialize property_kind and

  // property_num, and use enum's for the Property type (see

  // graph/properties.hpp), but the user may want to use a class

  // instead with a nested kind type and num.  Also, we may want to

  // switch BGL back to using class types for properties at some point.

  template <class PropertyTag>

  struct property_kind {

    typedef typename PropertyTag::kind type;

  };

  template <class P>

  struct has_property { 

    BOOST_STATIC_CONSTANT(bool, value = true);

    typedef true_type type;

  };

  template <>

  struct has_property<no_property> { 

    BOOST_STATIC_CONSTANT(bool, value = false); 

    typedef false_type type; 

  };

} // namespace boost

#include <boost/pending/detail/property.hpp>

namespace boost {

  template <class PropertyList, class Tag>

  struct property_value {

#if !defined BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION

    typedef typename detail::build_property_tag_value_alist<PropertyList>::type AList;

    typedef typename detail::extract_value<AList,Tag>::type type;

#else

    typedef typename detail::build_property_tag_value_alist<PropertyList>::type AList;

    typedef typename detail::ev_selector<AList>::type Extractor;

    typedef typename Extractor::template bind_<AList,Tag>::type type;

#endif  

  };

  template <class Tag1, class Tag2, class T1, class Base>

  inline typename property_value<property<Tag1,T1,Base>, Tag2>::type& 

  get_property_value(property<Tag1,T1,Base>& p, Tag2 tag2) {

    BOOST_STATIC_CONSTANT(bool, 

                          match = (detail::same_property<Tag1,Tag2>::value));

    typedef property<Tag1,T1,Base> Prop;

    typedef typename property_value<Prop, Tag2>::type T2;

    T2* t2 = 0;

    typedef detail::property_value_dispatch<match> Dispatcher;

    return Dispatcher::get_value(p, t2, tag2);

  }

  template <class Tag1, class Tag2, class T1, class Base>

  inline

  const typename property_value<property<Tag1,T1,Base>, Tag2>::type& 

  get_property_value(const property<Tag1,T1,Base>& p, Tag2 tag2) {

    BOOST_STATIC_CONSTANT(bool, 

                          match = (detail::same_property<Tag1,Tag2>::value));

    typedef property<Tag1,T1,Base> Prop;

    typedef typename property_value<Prop, Tag2>::type T2;

    T2* t2 = 0;

    typedef detail::property_value_dispatch<match> Dispatcher;

    return Dispatcher::const_get_value(p, t2, tag2);

  }

 namespace detail {

#if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)

   template<typename FinalTag, typename FinalType>

   struct retag_property_list

   {

     typedef property<FinalTag, FinalType> type;

     typedef FinalType retagged;

   };

   template<typename FinalTag, typename Tag, typename T, typename Base>

   struct retag_property_list<FinalTag, property<Tag, T, Base> >

   {

   private:

     typedef retag_property_list<FinalTag, Base> next;

   public:

     typedef property<Tag, T, typename next::type> type;

     typedef typename next::retagged retagged;

   };

   template<typename FinalTag>

   struct retag_property_list<FinalTag, no_property>

   {

     typedef no_property type;

     typedef no_property retagged;

   };

#endif

  }

} // namesapce boost

#endif /* BOOST_PROPERTY_HPP */