// charset.hpp
// Copyright (c) 2005-2012 Ben Hanson (http://www.benhanson.net/)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file licence_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

#ifndef LEXERTL_CHARSET_HPP
#define LEXERTL_CHARSET_HPP

#include <algorithm>
#include <iterator>
#include <set>
#include "../size_t.hpp"
#include "../string_token.hpp"

namespace lexertl
{
namespace detail
{
template<typename char_type, typename id_type>
struct basic_charset
{
    typedef basic_string_token<char_type> token;
    typedef std::set<id_type> index_set;

    token _token;
    index_set _index_set;

    basic_charset () :
        _token (),
        _index_set ()
    {
    }

    basic_charset (const token &token_, const std::size_t index_) :
        _token (token_),
        _index_set ()
    {
        _index_set.insert (index_);
    }

    bool empty () const
    {
        return _token.empty () && _index_set.empty ();
    }

    void intersect (basic_charset &rhs_, basic_charset &overlap_)
    {
        _token.intersect (rhs_._token, overlap_._token);

        if (!overlap_._token.empty ())
        {
            std::merge (_index_set.begin (), _index_set.end (),
                rhs_._index_set.begin (), rhs_._index_set.end (),
                std::inserter (overlap_._index_set,
                overlap_._index_set.end ()));

            if (_token.empty ())
            {
                _index_set.clear ();
            }

            if (rhs_._token.empty ())
            {
                rhs_._index_set.clear ();
            }
        }
    }
};
}
}

#endif