move BFS component exploration into Algorithms/
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Dennis Luxen
parent
a6b4658138
commit
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#ifndef __BFS_COMPONENT_EXPLORER_H__
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#define __BFS_COMPONENT_EXPLORER_H__
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#include <queue>
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#include <boost/unordered_set.hpp>
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#include "../typedefs.h"
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#include "../DataStructures/DynamicGraph.h"
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#include "../DataStructures/RestrictionMap.h"
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/**
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* Explores the components of the given graph while respecting turn restrictions
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* and barriers.
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*/
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template <typename GraphT> class BFSComponentExplorer
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{
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public:
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typedef typename GraphT::NodeIterator NodeIterator;
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typedef typename GraphT::EdgeIterator EdgeIterator;
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BFSComponentExplorer(const GraphT &dynamicGraph,
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const RestrictionMap &restrictions,
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const boost::unordered_set<NodeID> &barrier_nodes)
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: m_graph(dynamicGraph), m_restriction_map(restrictions), m_barrier_nodes(barrier_nodes)
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{
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BOOST_ASSERT(m_graph.GetNumberOfNodes() > 0);
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}
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/*!
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* Returns the size of the component that the node belongs to.
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*/
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inline unsigned int getComponentSize(NodeID node)
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{
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BOOST_ASSERT(node < m_component_index_list.size());
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return m_component_index_size[m_component_index_list[node]];
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}
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inline unsigned int getNumberOfComponents() { return m_component_index_size.size(); }
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/*!
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* Computes the component sizes.
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*/
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void run()
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{
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std::queue<std::pair<NodeID, NodeID>> bfs_queue;
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unsigned current_component = 0;
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BOOST_ASSERT(m_component_index_list.empty());
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BOOST_ASSERT(m_component_index_size.empty());
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unsigned num_nodes = m_graph.GetNumberOfNodes();
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m_component_index_list.resize(num_nodes, std::numeric_limits<unsigned>::max());
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BOOST_ASSERT(num_nodes > 0);
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// put unexplorered node with parent pointer into queue
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for (NodeID node = 0; node < num_nodes; ++node)
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{
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if (std::numeric_limits<unsigned>::max() == m_component_index_list[node])
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{
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unsigned size = exploreComponent(bfs_queue, node, current_component);
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// push size into vector
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m_component_index_size.push_back(size);
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++current_component;
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}
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}
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}
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private:
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/*!
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* Explores the current component that starts at node using BFS.
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*/
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inline unsigned exploreComponent(std::queue<std::pair<NodeID, NodeID>> &bfs_queue,
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NodeID node,
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unsigned current_component)
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{
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bfs_queue.push(std::make_pair(node, node));
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// mark node as read
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m_component_index_list[node] = current_component;
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unsigned current_component_size = 1;
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while (!bfs_queue.empty())
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{
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// fetch element from BFS queue
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std::pair<NodeID, NodeID> current_queue_item = bfs_queue.front();
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bfs_queue.pop();
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const NodeID v = current_queue_item.first; // current node
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const NodeID u = current_queue_item.second; // parent
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// increment size counter of current component
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++current_component_size;
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const bool is_barrier_node = (m_barrier_nodes.find(v) != m_barrier_nodes.end());
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if (!is_barrier_node)
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{
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const NodeID to_node_of_only_restriction =
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m_restriction_map.CheckForEmanatingIsOnlyTurn(u, v);
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for (EdgeIterator e2 = m_graph.BeginEdges(v); e2 < m_graph.EndEdges(v); ++e2)
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{
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NodeIterator w = m_graph.GetTarget(e2);
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if (to_node_of_only_restriction != std::numeric_limits<unsigned>::max() &&
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w != to_node_of_only_restriction)
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{
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// At an only_-restriction but not at the right turn
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continue;
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}
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if (u != w)
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{
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// only add an edge if turn is not a U-turn except
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// when it is at the end of a dead-end street.
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if (!m_restriction_map.CheckIfTurnIsRestricted(u, v, w))
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{
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// only add an edge if turn is not prohibited
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if (std::numeric_limits<unsigned>::max() == m_component_index_list[w])
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{
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// insert next (node, parent) only if w has
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// not yet been explored
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// mark node as read
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m_component_index_list[w] = current_component;
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bfs_queue.push(std::make_pair(w, v));
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}
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}
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}
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}
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}
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}
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return current_component_size;
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}
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std::vector<unsigned> m_component_index_list;
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std::vector<NodeID> m_component_index_size;
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const GraphT &m_graph;
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const RestrictionMap &m_restriction_map;
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const boost::unordered_set<NodeID> &m_barrier_nodes;
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};
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#endif
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