osrm-backend/src/extractor/edge_based_graph_factory.cpp

#include "extractor/edge_based_graph_factory.hpp"
#include "extractor/edge_based_edge.hpp"
#include "util/coordinate.hpp"
#include "util/coordinate_calculation.hpp"
#include "util/exception.hpp"
#include "util/integer_range.hpp"
#include "util/percent.hpp"
#include "util/simple_logger.hpp"
#include "util/timing_util.hpp"

#include "extractor/guidance/toolkit.hpp"
#include "extractor/guidance/turn_analysis.hpp"
#include "extractor/guidance/turn_lane_handler.hpp"
#include "extractor/scripting_environment.hpp"
#include "extractor/suffix_table.hpp"

#include <boost/assert.hpp>
#include <boost/numeric/conversion/cast.hpp>

#include <algorithm>
#include <cmath>
#include <fstream>
#include <iomanip>
#include <limits>
#include <sstream>
#include <string>
#include <unordered_map>

namespace osrm
{
namespace extractor
{
// Configuration to find representative candidate for turn angle calculations

EdgeBasedGraphFactory::EdgeBasedGraphFactory(
    std::shared_ptr<util::NodeBasedDynamicGraph> node_based_graph,
    const CompressedEdgeContainer &compressed_edge_container,
    const std::unordered_set<NodeID> &barrier_nodes,
    const std::unordered_set<NodeID> &traffic_lights,
    std::shared_ptr<const RestrictionMap> restriction_map,
    const std::vector<QueryNode> &node_info_list,
    ProfileProperties profile_properties,
    const util::NameTable &name_table,
    const std::vector<std::uint32_t> &turn_lane_offsets,
    const std::vector<guidance::TurnLaneType::Mask> &turn_lane_masks)
    : m_max_edge_id(0), m_node_info_list(node_info_list),
      m_node_based_graph(std::move(node_based_graph)),
      m_restriction_map(std::move(restriction_map)), m_barrier_nodes(barrier_nodes),
      m_traffic_lights(traffic_lights), m_compressed_edge_container(compressed_edge_container),
      profile_properties(std::move(profile_properties)), name_table(name_table),
      turn_lane_offsets(turn_lane_offsets), turn_lane_masks(turn_lane_masks)
{
}

void EdgeBasedGraphFactory::GetEdgeBasedEdges(
    util::DeallocatingVector<EdgeBasedEdge> &output_edge_list)
{
    BOOST_ASSERT_MSG(0 == output_edge_list.size(), "Vector is not empty");
    using std::swap; // Koenig swap
    swap(m_edge_based_edge_list, output_edge_list);
}

void EdgeBasedGraphFactory::GetEdgeBasedNodes(std::vector<EdgeBasedNode> &nodes)
{
#ifndef NDEBUG
    for (const EdgeBasedNode &node : m_edge_based_node_list)
    {
        BOOST_ASSERT(
            util::Coordinate(m_node_info_list[node.u].lon, m_node_info_list[node.u].lat).IsValid());
        BOOST_ASSERT(
            util::Coordinate(m_node_info_list[node.v].lon, m_node_info_list[node.v].lat).IsValid());
    }
#endif
    using std::swap; // Koenig swap
    swap(nodes, m_edge_based_node_list);
}

void EdgeBasedGraphFactory::GetStartPointMarkers(std::vector<bool> &node_is_startpoint)
{
    using std::swap; // Koenig swap
    swap(m_edge_based_node_is_startpoint, node_is_startpoint);
}

void EdgeBasedGraphFactory::GetEdgeBasedNodeWeights(std::vector<EdgeWeight> &output_node_weights)
{
    using std::swap; // Koenig swap
    swap(m_edge_based_node_weights, output_node_weights);
}

EdgeID EdgeBasedGraphFactory::GetHighestEdgeID() { return m_max_edge_id; }

void EdgeBasedGraphFactory::InsertEdgeBasedNode(const NodeID node_u, const NodeID node_v)
{
    // merge edges together into one EdgeBasedNode
    BOOST_ASSERT(node_u != SPECIAL_NODEID);
    BOOST_ASSERT(node_v != SPECIAL_NODEID);

    // find forward edge id and
    const EdgeID edge_id_1 = m_node_based_graph->FindEdge(node_u, node_v);
    BOOST_ASSERT(edge_id_1 != SPECIAL_EDGEID);

    const EdgeData &forward_data = m_node_based_graph->GetEdgeData(edge_id_1);

    // find reverse edge id and
    const EdgeID edge_id_2 = m_node_based_graph->FindEdge(node_v, node_u);
    BOOST_ASSERT(edge_id_2 != SPECIAL_EDGEID);

    const EdgeData &reverse_data = m_node_based_graph->GetEdgeData(edge_id_2);

    if (forward_data.edge_id == SPECIAL_NODEID && reverse_data.edge_id == SPECIAL_NODEID)
    {
        return;
    }

    if (forward_data.edge_id != SPECIAL_NODEID && reverse_data.edge_id == SPECIAL_NODEID)
        m_edge_based_node_weights[forward_data.edge_id] = INVALID_EDGE_WEIGHT;

    BOOST_ASSERT(m_compressed_edge_container.HasEntryForID(edge_id_1) ==
                 m_compressed_edge_container.HasEntryForID(edge_id_2));
    BOOST_ASSERT(m_compressed_edge_container.HasEntryForID(edge_id_1));
    BOOST_ASSERT(m_compressed_edge_container.HasEntryForID(edge_id_2));
    const auto &forward_geometry = m_compressed_edge_container.GetBucketReference(edge_id_1);
    BOOST_ASSERT(forward_geometry.size() ==
                 m_compressed_edge_container.GetBucketReference(edge_id_2).size());
    const auto geometry_size = forward_geometry.size();

    // There should always be some geometry
    BOOST_ASSERT(0 != geometry_size);

    NodeID current_edge_source_coordinate_id = node_u;

    const auto edge_id_to_segment_id = [](const NodeID edge_based_node_id) {
        if (edge_based_node_id == SPECIAL_NODEID)
        {
            return SegmentID{SPECIAL_SEGMENTID, false};
        }

        return SegmentID{edge_based_node_id, true};
    };

    // traverse arrays from start and end respectively
    for (const auto i : util::irange(std::size_t{0}, geometry_size))
    {
        BOOST_ASSERT(
            current_edge_source_coordinate_id ==
            m_compressed_edge_container.GetBucketReference(edge_id_2)[geometry_size - 1 - i]
                .node_id);
        const NodeID current_edge_target_coordinate_id = forward_geometry[i].node_id;
        BOOST_ASSERT(current_edge_target_coordinate_id != current_edge_source_coordinate_id);

        // build edges
        m_edge_based_node_list.emplace_back(edge_id_to_segment_id(forward_data.edge_id),
                                            edge_id_to_segment_id(reverse_data.edge_id),
                                            current_edge_source_coordinate_id,
                                            current_edge_target_coordinate_id,
                                            forward_data.name_id,
                                            m_compressed_edge_container.GetPositionForID(edge_id_1),
                                            m_compressed_edge_container.GetPositionForID(edge_id_2),
                                            false,
                                            INVALID_COMPONENTID,
                                            i,
                                            forward_data.travel_mode,
                                            reverse_data.travel_mode);

        m_edge_based_node_is_startpoint.push_back(forward_data.startpoint ||
                                                  reverse_data.startpoint);
        current_edge_source_coordinate_id = current_edge_target_coordinate_id;
    }

    BOOST_ASSERT(current_edge_source_coordinate_id == node_v);
}

void EdgeBasedGraphFactory::FlushVectorToStream(
    std::ofstream &edge_data_file, std::vector<OriginalEdgeData> &original_edge_data_vector) const
{
    if (original_edge_data_vector.empty())
    {
        return;
    }
    edge_data_file.write((char *)&(original_edge_data_vector[0]),
                         original_edge_data_vector.size() * sizeof(OriginalEdgeData));
    original_edge_data_vector.clear();
}

void EdgeBasedGraphFactory::Run(ScriptingEnvironment &scripting_environment,
                                const std::string &original_edge_data_filename,
                                const std::string &turn_lane_data_filename,
                                const std::string &edge_segment_lookup_filename,
                                const std::string &edge_penalty_filename,
                                const bool generate_edge_lookup)
{
    TIMER_START(renumber);
    m_max_edge_id = RenumberEdges() - 1;
    TIMER_STOP(renumber);

    TIMER_START(generate_nodes);
    m_edge_based_node_weights.reserve(m_max_edge_id + 1);
    GenerateEdgeExpandedNodes();
    TIMER_STOP(generate_nodes);

    TIMER_START(generate_edges);
    GenerateEdgeExpandedEdges(scripting_environment,
                              original_edge_data_filename,
                              turn_lane_data_filename,
                              edge_segment_lookup_filename,
                              edge_penalty_filename,
                              generate_edge_lookup);

    TIMER_STOP(generate_edges);

    util::SimpleLogger().Write() << "Timing statistics for edge-expanded graph:";
    util::SimpleLogger().Write() << "Renumbering edges: " << TIMER_SEC(renumber) << "s";
    util::SimpleLogger().Write() << "Generating nodes: " << TIMER_SEC(generate_nodes) << "s";
    util::SimpleLogger().Write() << "Generating edges: " << TIMER_SEC(generate_edges) << "s";
}

/// Renumbers all _forward_ edges and sets the edge_id.
/// A specific numbering is not important. Any unique ID will do.
/// Returns the number of edge based nodes.
unsigned EdgeBasedGraphFactory::RenumberEdges()
{
    // renumber edge based node of outgoing edges
    unsigned numbered_edges_count = 0;
    for (const auto current_node : util::irange(0u, m_node_based_graph->GetNumberOfNodes()))
    {
        for (const auto current_edge : m_node_based_graph->GetAdjacentEdgeRange(current_node))
        {
            EdgeData &edge_data = m_node_based_graph->GetEdgeData(current_edge);

            // only number incoming edges
            if (edge_data.reversed)
            {
                continue;
            }

            // oneway streets always require this self-loop. Other streets only if a u-turn plus
            // traversal
            // of the street takes longer than the loop
            m_edge_based_node_weights.push_back(edge_data.distance +
                                                profile_properties.u_turn_penalty);

            BOOST_ASSERT(numbered_edges_count < m_node_based_graph->GetNumberOfEdges());
            edge_data.edge_id = numbered_edges_count;
            ++numbered_edges_count;

            BOOST_ASSERT(SPECIAL_NODEID != edge_data.edge_id);
        }
    }

    return numbered_edges_count;
}

/// Creates the nodes in the edge expanded graph from edges in the node-based graph.
void EdgeBasedGraphFactory::GenerateEdgeExpandedNodes()
{
    util::Percent progress(m_node_based_graph->GetNumberOfNodes());

    // loop over all edges and generate new set of nodes
    for (const auto node_u : util::irange(0u, m_node_based_graph->GetNumberOfNodes()))
    {
        BOOST_ASSERT(node_u != SPECIAL_NODEID);
        BOOST_ASSERT(node_u < m_node_based_graph->GetNumberOfNodes());
        progress.PrintStatus(node_u);
        for (EdgeID e1 : m_node_based_graph->GetAdjacentEdgeRange(node_u))
        {
            const EdgeData &edge_data = m_node_based_graph->GetEdgeData(e1);
            BOOST_ASSERT(e1 != SPECIAL_EDGEID);
            const NodeID node_v = m_node_based_graph->GetTarget(e1);

            BOOST_ASSERT(SPECIAL_NODEID != node_v);
            // pick only every other edge, since we have every edge as an outgoing
            // and incoming egde
            if (node_u > node_v)
            {
                continue;
            }

            BOOST_ASSERT(node_u < node_v);

            // if we found a non-forward edge reverse and try again
            if (edge_data.edge_id == SPECIAL_NODEID)
            {
                InsertEdgeBasedNode(node_v, node_u);
            }
            else
            {
                InsertEdgeBasedNode(node_u, node_v);
            }
        }
    }

    BOOST_ASSERT(m_edge_based_node_list.size() == m_edge_based_node_is_startpoint.size());
    BOOST_ASSERT(m_max_edge_id + 1 == m_edge_based_node_weights.size());

    util::SimpleLogger().Write() << "Generated " << m_edge_based_node_list.size()
                                 << " nodes in edge-expanded graph";
}

/// Actually it also generates OriginalEdgeData and serializes them...
void EdgeBasedGraphFactory::GenerateEdgeExpandedEdges(
    ScriptingEnvironment &scripting_environment,
    const std::string &original_edge_data_filename,
    const std::string &turn_lane_data_filename,
    const std::string &edge_segment_lookup_filename,
    const std::string &edge_fixed_penalties_filename,
    const bool generate_edge_lookup)
{
    util::SimpleLogger().Write() << "generating edge-expanded edges";

    std::size_t node_based_edge_counter = 0;
    std::size_t original_edges_counter = 0;
    restricted_turns_counter = 0;
    skipped_uturns_counter = 0;
    skipped_barrier_turns_counter = 0;

    std::ofstream edge_data_file(original_edge_data_filename.c_str(), std::ios::binary);
    std::ofstream edge_segment_file;
    std::ofstream edge_penalty_file;

    if (generate_edge_lookup)
    {
        edge_segment_file.open(edge_segment_lookup_filename.c_str(), std::ios::binary);
        edge_penalty_file.open(edge_fixed_penalties_filename.c_str(), std::ios::binary);
    }

    // Writes a dummy value at the front that is updated later with the total length
    const unsigned length_prefix_empty_space{0};
    edge_data_file.write(reinterpret_cast<const char *>(&length_prefix_empty_space),
                         sizeof(length_prefix_empty_space));

    std::vector<OriginalEdgeData> original_edge_data_vector;
    original_edge_data_vector.reserve(1024 * 1024);

    // Loop over all turns and generate new set of edges.
    // Three nested loop look super-linear, but we are dealing with a (kind of)
    // linear number of turns only.
    util::Percent progress(m_node_based_graph->GetNumberOfNodes());
    SuffixTable street_name_suffix_table(scripting_environment);
    guidance::TurnAnalysis turn_analysis(*m_node_based_graph,
                                         m_node_info_list,
                                         *m_restriction_map,
                                         m_barrier_nodes,
                                         m_compressed_edge_container,
                                         name_table,
                                         street_name_suffix_table,
                                         profile_properties);
    guidance::lanes::TurnLaneHandler turn_lane_handler(
        *m_node_based_graph, turn_lane_offsets, turn_lane_masks, turn_analysis);

    bearing_class_by_node_based_node.resize(m_node_based_graph->GetNumberOfNodes(),
                                            std::numeric_limits<std::uint32_t>::max());

    guidance::LaneDataIdMap lane_data_map;
    for (const auto node_u : util::irange(0u, m_node_based_graph->GetNumberOfNodes()))
    {
        progress.PrintStatus(node_u);
        for (const EdgeID edge_from_u : m_node_based_graph->GetAdjacentEdgeRange(node_u))
        {
            if (m_node_based_graph->GetEdgeData(edge_from_u).reversed)
            {
                continue;
            }

            const NodeID node_v = m_node_based_graph->GetTarget(edge_from_u);
            ++node_based_edge_counter;
            auto intersection = turn_analysis.getIntersection(node_u, edge_from_u);
            intersection =
                turn_analysis.assignTurnTypes(node_u, edge_from_u, std::move(intersection));

            intersection = turn_lane_handler.assignTurnLanes(
                node_u, edge_from_u, std::move(intersection), lane_data_map);
            const auto possible_turns = turn_analysis.transformIntersectionIntoTurns(intersection);

            // the entry class depends on the turn, so we have to classify the interesction for
            // every edge
            const auto turn_classification = classifyIntersection(node_v,
                                                                  intersection,
                                                                  *m_node_based_graph,
                                                                  m_compressed_edge_container,
                                                                  m_node_info_list);

            const auto entry_class_id = [&](const util::guidance::EntryClass entry_class) {
                if (0 == entry_class_hash.count(entry_class))
                {
                    const auto id = static_cast<std::uint16_t>(entry_class_hash.size());
                    entry_class_hash[entry_class] = id;
                    return id;
                }
                else
                {
                    return entry_class_hash.find(entry_class)->second;
                }
            }(turn_classification.first);

            const auto bearing_class_id = [&](const util::guidance::BearingClass bearing_class) {
                if (0 == bearing_class_hash.count(bearing_class))
                {
                    const auto id = static_cast<std::uint32_t>(bearing_class_hash.size());
                    bearing_class_hash[bearing_class] = id;
                    return id;
                }
                else
                {
                    return bearing_class_hash.find(bearing_class)->second;
                }
            }(turn_classification.second);
            bearing_class_by_node_based_node[node_v] = bearing_class_id;

            for (const auto turn : possible_turns)
            {
                // only add an edge if turn is not prohibited
                const EdgeData &edge_data1 = m_node_based_graph->GetEdgeData(edge_from_u);
                const EdgeData &edge_data2 = m_node_based_graph->GetEdgeData(turn.eid);

                BOOST_ASSERT(edge_data1.edge_id != edge_data2.edge_id);
                BOOST_ASSERT(!edge_data1.reversed);
                BOOST_ASSERT(!edge_data2.reversed);

                // the following is the core of the loop.
                unsigned distance = edge_data1.distance;
                if (m_traffic_lights.find(node_v) != m_traffic_lights.end())
                {
                    distance += profile_properties.traffic_signal_penalty;
                }

                const int32_t turn_penalty =
                    scripting_environment.GetTurnPenalty(180. - turn.angle);
                const auto turn_instruction = turn.instruction;

                if (turn_instruction.direction_modifier == guidance::DirectionModifier::UTurn)
                {
                    distance += profile_properties.u_turn_penalty;
                }

                distance += turn_penalty;

                BOOST_ASSERT(m_compressed_edge_container.HasEntryForID(edge_from_u));
                original_edge_data_vector.emplace_back(
                    m_compressed_edge_container.GetPositionForID(edge_from_u),
                    edge_data1.name_id,
                    turn.lane_data_id,
                    turn_instruction,
                    entry_class_id,
                    edge_data1.travel_mode);

                ++original_edges_counter;

                if (original_edge_data_vector.size() > 1024 * 1024 * 10)
                {
                    FlushVectorToStream(edge_data_file, original_edge_data_vector);
                }

                BOOST_ASSERT(SPECIAL_NODEID != edge_data1.edge_id);
                BOOST_ASSERT(SPECIAL_NODEID != edge_data2.edge_id);

                // NOTE: potential overflow here if we hit 2^32 routable edges
                BOOST_ASSERT(m_edge_based_edge_list.size() <= std::numeric_limits<NodeID>::max());
                m_edge_based_edge_list.emplace_back(edge_data1.edge_id,
                                                    edge_data2.edge_id,
                                                    m_edge_based_edge_list.size(),
                                                    distance,
                                                    true,
                                                    false);

                // Here is where we write out the mapping between the edge-expanded edges, and
                // the node-based edges that are originally used to calculate the `distance`
                // for the edge-expanded edges.  About 40 lines back, there is:
                //
                //                 unsigned distance = edge_data1.distance;
                //
                // This tells us that the weight for an edge-expanded-edge is based on the weight
                // of the *source* node-based edge.  Therefore, we will look up the individual
                // segments of the source node-based edge, and write out a mapping between
                // those and the edge-based-edge ID.
                // External programs can then use this mapping to quickly perform
                // updates to the edge-expanded-edge based directly on its ID.
                if (generate_edge_lookup)
                {
                    const auto node_based_edges =
                        m_compressed_edge_container.GetBucketReference(edge_from_u);
                    NodeID previous = node_u;

                    const unsigned node_count = node_based_edges.size() + 1;
                    const QueryNode &first_node = m_node_info_list[previous];

                    lookup::SegmentHeaderBlock header = {node_count, first_node.node_id};

                    edge_segment_file.write(reinterpret_cast<const char *>(&header),
                                            sizeof(header));

                    for (auto target_node : node_based_edges)
                    {
                        const QueryNode &from = m_node_info_list[previous];
                        const QueryNode &to = m_node_info_list[target_node.node_id];
                        const double segment_length =
                            util::coordinate_calculation::greatCircleDistance(from, to);

                        lookup::SegmentBlock nodeblock = {
                            to.node_id, segment_length, target_node.weight};

                        edge_segment_file.write(reinterpret_cast<const char *>(&nodeblock),
                                                sizeof(nodeblock));
                        previous = target_node.node_id;
                    }

                    // We also now write out the mapping between the edge-expanded edges and the
                    // original nodes. Since each edge represents a possible maneuver, external
                    // programs can use this to quickly perform updates to edge weights in order
                    // to penalize certain turns.

                    // If this edge is 'trivial' -- where the compressed edge corresponds
                    // exactly to an original OSM segment -- we can pull the turn's preceding
                    // node ID directly with `node_u`; otherwise, we need to look up the node
                    // immediately preceding the turn from the compressed edge container.
                    const bool isTrivial = m_compressed_edge_container.IsTrivial(edge_from_u);

                    const auto &from_node =
                        isTrivial
                            ? m_node_info_list[node_u]
                            : m_node_info_list[m_compressed_edge_container.GetLastEdgeSourceID(
                                  edge_from_u)];
                    const auto &via_node =
                        m_node_info_list[m_compressed_edge_container.GetLastEdgeTargetID(
                            edge_from_u)];
                    const auto &to_node =
                        m_node_info_list[m_compressed_edge_container.GetFirstEdgeTargetID(
                            turn.eid)];

                    const unsigned fixed_penalty = distance - edge_data1.distance;
                    lookup::PenaltyBlock penaltyblock = {
                        fixed_penalty, from_node.node_id, via_node.node_id, to_node.node_id};
                    edge_penalty_file.write(reinterpret_cast<const char *>(&penaltyblock),
                                            sizeof(penaltyblock));
                }
            }
        }
    }

    util::SimpleLogger().Write() << "Created " << entry_class_hash.size() << " entry classes and "
                                 << bearing_class_hash.size() << " Bearing Classes";

    util::SimpleLogger().Write() << "Writing Turn Lane Data to File...";
    std::ofstream turn_lane_data_file(turn_lane_data_filename.c_str(), std::ios::binary);
    std::vector<util::guidance::LaneTupelIdPair> lane_data(lane_data_map.size());
    // extract lane data sorted by ID
    for (auto itr : lane_data_map)
        lane_data[itr.second] = itr.first;

    std::uint64_t size = lane_data.size();
    turn_lane_data_file.write(reinterpret_cast<const char *>(&size), sizeof(size));

    if (!lane_data.empty())
        turn_lane_data_file.write(reinterpret_cast<const char *>(&lane_data[0]),
                                  sizeof(util::guidance::LaneTupelIdPair) * lane_data.size());

    util::SimpleLogger().Write() << "done.";

    FlushVectorToStream(edge_data_file, original_edge_data_vector);

    // Finally jump back to the empty space at the beginning and write length prefix
    edge_data_file.seekp(std::ios::beg);

    const auto length_prefix = boost::numeric_cast<unsigned>(original_edges_counter);
    static_assert(sizeof(length_prefix_empty_space) == sizeof(length_prefix), "type mismatch");

    edge_data_file.write(reinterpret_cast<const char *>(&length_prefix), sizeof(length_prefix));

    util::SimpleLogger().Write() << "Generated " << m_edge_based_node_list.size()
                                 << " edge based nodes";
    util::SimpleLogger().Write() << "Node-based graph contains " << node_based_edge_counter
                                 << " edges";
    util::SimpleLogger().Write() << "Edge-expanded graph ...";
    util::SimpleLogger().Write() << "  contains " << m_edge_based_edge_list.size() << " edges";
    util::SimpleLogger().Write() << "  skips " << restricted_turns_counter << " turns, "
                                                                              "defined by "
                                 << m_restriction_map->size() << " restrictions";
    util::SimpleLogger().Write() << "  skips " << skipped_uturns_counter << " U turns";
    util::SimpleLogger().Write() << "  skips " << skipped_barrier_turns_counter
                                 << " turns over barriers";
}

std::vector<util::guidance::BearingClass> EdgeBasedGraphFactory::GetBearingClasses() const
{
    std::vector<util::guidance::BearingClass> result(bearing_class_hash.size());
    for (const auto &pair : bearing_class_hash)
    {
        BOOST_ASSERT(pair.second < result.size());
        result[pair.second] = pair.first;
    }
    return result;
}

const std::vector<BearingClassID> &EdgeBasedGraphFactory::GetBearingClassIds() const
{
    return bearing_class_by_node_based_node;
}

std::vector<BearingClassID> &EdgeBasedGraphFactory::GetBearingClassIds()
{
    return bearing_class_by_node_based_node;
}

std::vector<util::guidance::EntryClass> EdgeBasedGraphFactory::GetEntryClasses() const
{
    std::vector<util::guidance::EntryClass> result(entry_class_hash.size());
    for (const auto &pair : entry_class_hash)
    {
        BOOST_ASSERT(pair.second < result.size());
        result[pair.second] = pair.first;
    }
    return result;
}

} // namespace extractor
} // namespace osrm