// Copyright (C) Vladimir Prus 2003.

// 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)

//

// See http://www.boost.org/libs/graph/vector_property_map.html for

// documentation.

//

#ifndef VECTOR_PROPERTY_MAP_HPP_VP_2003_03_04

#define VECTOR_PROPERTY_MAP_HPP_VP_2003_03_04

#include <boost/property_map.hpp>

#include <boost/shared_ptr.hpp>

#include <vector>

namespace boost {

    template<typename T, typename IndexMap = identity_property_map>

    class vector_property_map

        : public boost::put_get_helper< 

              typename std::iterator_traits< 

                  typename std::vector<T>::iterator >::reference,

              vector_property_map<T, IndexMap> >

    {

    public:

        typedef typename property_traits<IndexMap>::key_type  key_type;

        typedef T value_type;

        typedef typename std::iterator_traits< 

            typename std::vector<T>::iterator >::reference reference;

        typedef boost::lvalue_property_map_tag category;

        vector_property_map(const IndexMap& index = IndexMap())

        : store(new std::vector<T>()), index(index)

        {}

        vector_property_map(unsigned initial_size, 

                            const IndexMap& index = IndexMap())

        : store(new std::vector<T>(initial_size)), index(index)

        {}

        typename std::vector<T>::iterator storage_begin()

        {

            return store->begin();

        }

        typename std::vector<T>::iterator storage_end()

        {

            return store->end();

        }

        typename std::vector<T>::const_iterator storage_begin() const

        {

            return store->begin();

        }

        typename std::vector<T>::const_iterator storage_end() const

        {

            return store->end();

        }

    public:

        // Copy ctor absent, default semantics is OK.

        // Assignment operator absent, default semantics is OK.

        // CONSIDER: not sure that assignment to 'index' is correct.

        reference operator[](const key_type& v) const {

            typename property_traits<IndexMap>::value_type i = get(index, v);

            if (static_cast<unsigned>(i) >= store->size()) {

                store->resize(i + 1, T());

            }

            return (*store)[i];

        }

    private:

        // Conceptually, we have a vector of infinite size. For practical 

        // purposes, we start with an empty vector and grow it as needed.

        // Note that we cannot store pointer to vector here -- we cannot

        // store pointer to data, because if copy of property map resizes

        // the vector, the pointer to data will be invalidated. 

        // I wonder if class 'pmap_ref' is simply needed.

        shared_ptr< std::vector<T> > store;        

        IndexMap index;

    };

    template<typename T, typename IndexMap>

    vector_property_map<T, IndexMap>

    make_vector_property_map(IndexMap index)

    {

        return vector_property_map<T, IndexMap>(index);

    }

}

#endif