AtomRDF.hpp

/* This file is part of Raul.
 * Copyright (C) 2007-2009 David Robillard <http://drobilla.net>
 *
 * Raul is free software; you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free Software
 * Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * Raul is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifndef RAUL_ATOM_RDF_HPP
#define RAUL_ATOM_RDF_HPP

#include <cmath>
#include <cstring>
#include <sstream>
#include <string>
#include <utility>

#include "raul/Atom.hpp"
#include "raul/log.hpp"
#include "redlandmm/Model.hpp"
#include "redlandmm/Node.hpp"
#include "redlandmm/World.hpp"

#define CUC(x) ((const unsigned char*)(x))

namespace Raul {

namespace AtomRDF {

inline Atom
node_to_atom(Redland::Model& model, const Redland::Node& node)
{
    if (node.is_bool()) {
        return Atom(bool(node.to_bool()));
    } else if (node.is_resource()) {
        return Atom(Atom::URI, node.to_c_string());
    } else if (node.is_float()) {
        return Atom(node.to_float());
    } else if (node.is_int()) {
        return Atom(node.to_int());
    } else if (node.is_blank()) {
        Atom::DictValue dict;
        librdf_statement* pattern = librdf_new_statement_from_nodes(
                model.world().c_obj(),
                const_cast<librdf_node*>(node.c_obj()),
                NULL,
                NULL);
        librdf_stream* results = librdf_model_find_statements(
                const_cast<librdf_model*>(model.c_obj()),
                pattern);
        while (!librdf_stream_end(results)) {
            librdf_statement* s = librdf_stream_get_object(results);
            Redland::Node predicate(model.world(), librdf_statement_get_predicate(s));
            Redland::Node object(model.world(), librdf_statement_get_object(s));
            dict.insert(std::make_pair(node_to_atom(model, predicate), node_to_atom(model, object)));
            librdf_stream_next(results);
        }
        return Atom(dict);
    } else {
        return Atom(node.to_c_string());
    }
}


inline Redland::Node
atom_to_node(Redland::Model& model, const Atom& atom)
{
    Redland::World& world = model.world();

    std::ostringstream os;
    std::string        str;
    librdf_uri*        type = NULL;
    librdf_node*       node = NULL;

    switch (atom.type()) {
    case Atom::INT:
        os << atom.get_int32();
        str = os.str();
        // xsd:integer -> pretty integer literals in Turtle
        type = librdf_new_uri(world.world(), CUC("http://www.w3.org/2001/XMLSchema#integer"));
        break;
    case Atom::FLOAT:
        if (std::isnan(atom.get_float()) || std::isinf(atom.get_float()))
            break;
        os.precision(8);
        os << atom.get_float();
        str = os.str();
        if (str.find(".") == std::string::npos)
            str += ".0";
        // xsd:decimal -> pretty decimal (float) literals in Turtle
        type = librdf_new_uri(world.world(), CUC("http://www.w3.org/2001/XMLSchema#decimal"));
        break;
    case Atom::BOOL:
        // xsd:boolean -> pretty boolean literals in Turtle
        if (atom.get_bool())
            str = "true";
        else
            str = "false";
        type = librdf_new_uri(world.world(), CUC("http://www.w3.org/2001/XMLSchema#boolean"));
        break;
    case Atom::URI:
        str = atom.get_uri();
        node = librdf_new_node_from_uri_string(world.world(), CUC(world.expand_uri(str).c_str()));
        break;
    case Atom::STRING:
        str = atom.get_string();
        break;
    case Atom::DICT:
        node = librdf_new_node(world.world());
        for (Atom::DictValue::const_iterator i = atom.get_dict().begin();
                i != atom.get_dict().end(); ++i) {
            model.add_statement(Redland::Node(world, node),
                    atom_to_node(model, i->first),
                    atom_to_node(model, i->second));
        }
        break;
    case Atom::BLOB:
    case Atom::NIL:
    default:
        warn << "Unserializable Atom" << std::endl;
        break;
    }

    if (!node && str != "")
        node = librdf_new_node_from_typed_literal(world.world(), CUC(str.c_str()), NULL, type);

    return Redland::Node(world, node);
}


} // namespace AtomRDF
} // namespace Raul

#endif // RAUL_ATOM_RDF_HPP