osrm-backend/DataStructures/RestrictionMap.cpp

#include "RestrictionMap.h"
#include "NodeBasedGraph.h"

RestrictionMap::RestrictionMap(const std::shared_ptr<NodeBasedDynamicGraph>& graph, const std::vector<TurnRestriction> & input_restrictions_list)
: m_count(0)
, m_graph(graph)
{
    // decompose restirction consisting of a start, via and end note into a start-edge
    // and all end-nodes
    for (auto& restriction : input_restrictions_list) {
        std::pair<NodeID, NodeID> restriction_source =
            std::make_pair(restriction.fromNode, restriction.viaNode);
        unsigned index;
        auto restriction_iter = m_restriction_map.find(restriction_source);
        if(restriction_iter == m_restriction_map.end()) {
            index = m_restriction_bucket_list.size();
            m_restriction_bucket_list.resize(index+1);
            m_restriction_map.emplace(restriction_source, index);
        } else {
            index = restriction_iter->second;
            //Map already contains an is_only_*-restriction
            if(m_restriction_bucket_list.at(index).begin()->second) {
                continue;
            } else if(restriction.flags.isOnly) {
                //We are going to insert an is_only_*-restriction. There can be only one.
                m_count -= m_restriction_bucket_list.at(index).size();
                m_restriction_bucket_list.at(index).clear();
            }
        }
        ++m_count;
        m_restriction_bucket_list.at(index).push_back(
            std::make_pair( restriction.toNode, restriction.flags.isOnly)
        );
    }
}

/**
 * Replace end v with w in each turn restriction containing u as via node
 *
 * Note: We need access to node based graph.
 */
void RestrictionMap::FixupArrivingTurnRestriction(
    const NodeID u,
    const NodeID v,
    const NodeID w
) {
    BOOST_ASSERT( u != std::numeric_limits<unsigned>::max() );
    BOOST_ASSERT( v != std::numeric_limits<unsigned>::max() );
    BOOST_ASSERT( w != std::numeric_limits<unsigned>::max() );

    // find all possible start edges
    // it is more efficent to get a (small) list of potential start edges
    // than iterating over all buckets
    std::vector<NodeID> predecessors;
    for(
        EdgeID current_edge_id = m_graph->BeginEdges(u);
        current_edge_id < m_graph->EndEdges(u);
        ++current_edge_id
    ) {
        const EdgeData & edge_data = m_graph->GetEdgeData(current_edge_id);
        const NodeID target = m_graph->GetTarget(current_edge_id);
        if( edge_data.backward && ( v != target) ) {
            predecessors.push_back(target);
        }
    }

    for(const NodeID x : predecessors) {
        const std::pair<NodeID, NodeID> restr_start = std::make_pair(x,u);
        auto restriction_iterator = m_restriction_map.find( restr_start );
        if( restriction_iterator == m_restriction_map.end() )
            continue;

        const unsigned index = restriction_iterator->second;
        auto& bucket = m_restriction_bucket_list.at(index);
        for(RestrictionTarget& restriction_target : bucket) {
            if( v == restriction_target.first ) {
                restriction_target.first = w;
            }
        }
    }
}

/**
 * Replaces the start edge (v, w) with (u, w), only start node changes.
 */
void RestrictionMap::FixupStartingTurnRestriction(
    const NodeID u,
    const NodeID v,
    const NodeID w
) {
    BOOST_ASSERT( u != std::numeric_limits<unsigned>::max() );
    BOOST_ASSERT( v != std::numeric_limits<unsigned>::max() );
    BOOST_ASSERT( w != std::numeric_limits<unsigned>::max() );

    const std::pair<NodeID, NodeID> old_start = std::make_pair(v,w);

    auto restriction_iterator = m_restriction_map.find( old_start );
    if( restriction_iterator != m_restriction_map.end() ) {
        const unsigned index = restriction_iterator->second;
        // remove old restriction start (v,w)
        m_restriction_map.erase( restriction_iterator );

        // insert new restriction start (u,w) (point to index)
        const std::pair<NodeID, NodeID> new_start = std::make_pair(u,w);
        m_restriction_map.insert( std::make_pair(new_start, index) );
    }
}

/*
 * Check if the edge (u, v) is contained in any turn restriction.
 * If so returns id of first target node.
 */
NodeID RestrictionMap::CheckForEmanatingIsOnlyTurn(
    const NodeID u,
    const NodeID v
) const {
    BOOST_ASSERT( u != std::numeric_limits<unsigned>::max() );
    BOOST_ASSERT( v != std::numeric_limits<unsigned>::max() );

    const std::pair<NodeID, NodeID> restriction_source = std::make_pair(u, v);
    auto restriction_iter = m_restriction_map.find(restriction_source);

    if (restriction_iter != m_restriction_map.end()) {
        const unsigned index = restriction_iter->second;
        auto& bucket = m_restriction_bucket_list.at(index);
        for(const RestrictionSource& restriction_target : bucket) {
            if(restriction_target.second) {
                return restriction_target.first;
            }
        }
    }

    return std::numeric_limits<unsigned>::max();
}

/**
 * Checks if the turn described by start u, via v and targed w is covert by any turn restriction.
 */
bool RestrictionMap::CheckIfTurnIsRestricted(
    const NodeID u,
    const NodeID v,
    const NodeID w
) const {
    BOOST_ASSERT( u != std::numeric_limits<unsigned>::max() );
    BOOST_ASSERT( v != std::numeric_limits<unsigned>::max() );
    BOOST_ASSERT( w != std::numeric_limits<unsigned>::max() );

    const std::pair<NodeID, NodeID> restriction_source = std::make_pair(u, v);
    auto restriction_iter = m_restriction_map.find(restriction_source);

    if (restriction_iter != m_restriction_map.end()) {
        const unsigned index = restriction_iter->second;
        auto& bucket = m_restriction_bucket_list.at(index);
        for(const RestrictionTarget & restriction_target : bucket) {
            if(
                ( w == restriction_target.first ) && // target found
                ( !restriction_target.second    )    // and not an only_-restr.
            ) {
                return true;
            }
        }
    }

    return false;
}