// Copyright David Abrahams 2002.

// 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 INSTANCE_DWA200295_HPP

# define INSTANCE_DWA200295_HPP

# include <boost/python/detail/prefix.hpp>

# include <boost/type_traits/alignment_traits.hpp>

# include <cstddef>

namespace boost { namespace python

{

  struct BOOST_PYTHON_DECL_FORWARD instance_holder;

}} // namespace boost::python

namespace boost { namespace python { namespace objects { 

// Each extension instance will be one of these

template <class Data = char>

struct instance

{

    PyObject_VAR_HEAD

    PyObject* dict;

    PyObject* weakrefs; 

    instance_holder* objects;

    typedef typename type_with_alignment<

        ::boost::alignment_of<Data>::value

    >::type align_t;

    union

    {

        align_t align;

        char bytes[sizeof(Data)];

    } storage;

};

template <class Data>

struct additional_instance_size

{

    typedef instance<Data> instance_data;

    typedef instance<char> instance_char;

    BOOST_STATIC_CONSTANT(

        std::size_t, value = sizeof(instance_data)

                           - BOOST_PYTHON_OFFSETOF(instance_char,storage));

};

}}} // namespace boost::python::object

#endif // INSTANCE_DWA200295_HPP