vectorgraph.h

/*
 *
 * This file is part of Tulip (www.tulip-software.org)
 *
 * Authors: David Auber and the Tulip development Team
 * from LaBRI, University of Bordeaux 1 and Inria Bordeaux - Sud Ouest
 *
 * Tulip is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation, either version 3
 * of the License, or (at your option) any later version.
 *
 * Tulip 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 more details.
 *
 */
///@cond DOXYGEN_HIDDEN


#ifndef VECTORGRAPH_H
#define VECTORGRAPH_H
#include <vector>
#include <algorithm>

#include <set>
#include <cassert>

#include <tulip/tulipconf.h>
#include <tulip/Node.h>
#include <tulip/Edge.h>
#include <tulip/vectorgraphproperty.h>

namespace tlp {

template<class itType >
struct Iterator;
//===========================================
/**
  * @class VectorGraph
  *
  * @brief That class provide a simple implementation of graph structure (without subgraphs, observer, metagraph)
  * it enables to obtain very efficient access/modification time.
  *
  * User can both use tulip iterators or direct vector to access to the graph structure for better performance.
  * To have maximum speedup, that Graph implementation use only vectors, almost all operations
  * are done in constant time (even modification), however since the class use vectors, modification
  * of adjacency can change the ordering of edges around nodes. If you use it only for standard
  * graph operations there is no problem. However if you want to manipulate maps, be aware that
  * a modification can change the graph embedding. EdgeOrdering function can be used to reorder
  * correctly elements when necessary.
  *
  * @warning the class is not thread safe
  * @warning modification of the graph structure devalidate iterations.
  *
  * @warning Use that class only if you need performance.
  * @todo split the file in .h .cpp
  */
class  TLP_SCOPE VectorGraph {

public:
  //=======================================================
  VectorGraph();
  //=======================================================
  ~VectorGraph();
  //=======================================================
  /**
        * @brief delete all nodes/edges and Properties of the graph
        * @remark o(N + E + NbProp)
        */
  void clear();
  //=======================================================
  /**
        * @brief Test if an edge exist between two nodes, in directed mode the orientation
        * is taken into account.
        * @return the found edge, else an invalid edge.
        * @remark o(min(deg(src), deg(tgt))
        * @todo test
        */
  edge existEdge(const node src, const node tgt, const bool directed = true) const;
  //=======================================================
  /**
        * @brief Return true if n belongs to the graph
        * @remark o(1)
        */
  bool isElement(const node n) const;
  //=======================================================
  /**
        * @brief Return true if e belongs to the graph
        * @remark o(1)
        */
  bool isElement(const edge e) const;
  //=======================================================
  /**
        * \brief Set the ordering of edges around n according to their order in v.
        * \warning there is no test here, all edge in v must be element of star(e)
        * @remark o(v.size())
        */
  void setEdgeOrder(const node n, const std::vector<edge> &v );
  //=======================================================
  /**
        * \brief swap to edge in the ordered adjacency vector
        * \warning the two edges must be element of star(v)
        * @remark o(1)
        */
  void swapEdgeOrder(const node n, const edge e1, const edge e2);
  //=======================================================
  /**
        * @brief Enables to reserve memory for nbNodes
        * Reserving memory before to addNode enable to reduce the number of vector resizing and then
        * to speed up significantly construction of graphs.
        * @remark o(N + nbNodes)
        */
  void reserveNodes(const size_t nbNodes);
  //=======================================================
  /**
        * @brief Enables to reserve memory for nbEdges
        * Reserving memory before to addEdge enable to reduce the number of vector resizing and then
        * to speed up significantly construction of graphs.
        * @remark o(N + nbNodes)
        */
  void reserveEdges(const size_t nbEdges);
  //=======================================================
  /**
        * @brief Enables to reserve memory for adjacency nodes
        * Reserving memory before to addEdge enable to reduce the number of vector resizing and then
        * to speed up significantly construction of graphs.
        * @remark o(E + nbEdges)
        */
  void reserveAdj(const size_t nbEdges);
  //=======================================================
  /**
        * @brief Enables to reserve memory for adjacency nodes
        * Reserving memory before to addEdge enable to reduce the number of vector resizing and then
        * to speed up significantly construction of graphs.
        * @remark o(E + nbEdges)
        */
  void reserveAdj(const node n, const size_t nbEdges);
  //=======================================================
  /**
        * @brief Return the node at position id in the array of nodes
        * @remark o(1)
        */
  node operator[](const unsigned int id) const;
  //=======================================================
  /**
        * @brief Return the edge at position id in the array of nodes
        * @remark o(1)
        */
  edge operator()(const unsigned int id) const;
  //=======================================================
  /**
        * @brief Return the first node of graph (ie first node in the array of nodes)
        * @remark o(1)
        */
  node getOneNode() const;
  //=======================================================
  /**
        * @brief Return a Tulip Iterator on nodes of the graph
        * @warning: The returned iterator should be deleted by the caller to prevent memory leaks
        * @remark: o(1)
        */
  Iterator<node> * getNodes() const;
  //=======================================================
  /**
        * @brief Return a Tulip Iterator on edges of the graph
        * @warning: The returned iterator should be deleted by the caller to prevent memory leaks
        * @remark: o(1)
        */
  Iterator<edge> * getEdges() const;
  //=======================================================
  /**
        * @brief Return a Tulip Iterator on adjacent edges of the node n
        * @warning: The returned iterator should be deleted by the caller to prevent memory leaks
        * @remark: o(1)
        */
  Iterator<edge> * getInOutEdges(const node n) const;
  //=======================================================
  /**
        * @brief Return a Tulip Iterator on out edges of the node n
        * @warning: The returned iterator should be deleted by the caller to prevent memory leaks
        * @remark: o(1)
        */
  Iterator<edge> * getOutEdges(const node n) const;
  //=======================================================
  /**
        * @brief Return a Tulip Iterator on in edges of the node n
        * @warning: The returned iterator should be deleted by the caller to prevent memory leaks
        * @remark: o(1)
        */
  Iterator<edge> * getInEdges(const node n) const;
  //=======================================================
  /**
        * @brief Return a Tulip Iterator on adjacent nodes of the node n
        * @warning: The returned iterator should be deleted by the caller to prevent memory leaks
        * @remark: o(1)
        */
  Iterator<node> * getInOutNodes(const node n) const;
  //=======================================================
  /**
        * @brief Return a Tulip Iterator on in nodes of the node n
        * @warning: The returned iterator should be deleted by the caller to prevent memory leaks
        * @remark o(1)
        */
  //=======================================================
  Iterator<node> * getInNodes(const node n) const;
  /**
        * @brief Return a Tulip Iterator on out nodes of the node n
        * @warning: The returned iterator should be deleted by the caller to prevent memory leaks
        * @remark o(1)
        */
  //=======================================================
  Iterator<node> * getOutNodes(const node n) const;
  //=======================================================
  /**
       * @brief Return the degree of a node
       * @remark o(1)
       */
  unsigned int deg(const node n) const;
  //=======================================================
  /**
       * @brief Return the out degree of a node
       * @remark o(1)
       */
  unsigned int outdeg(const node n) const;
  //=======================================================
  /**
       * @brief Return the in degree of a node
       * @remark o(1)
       */
  unsigned int indeg(const node n) const;
  //=======================================================
  /**
       * @brief Return the number of edges in the graph
       * @remark: o(1)
       */
  unsigned int numberOfEdges() const;
  //=======================================================
  /**
       * @brief Return the number of nodes in the graph
       * @remark: o(1)
       */
  unsigned int numberOfNodes() const;
  //=======================================================
  /**
       * @brief Add a new node in the graph and return it
       * @warning: That operation modify the array of nodes
       * and thus devalidate all iterators on it.
       * @remark: o(1)
       */
  node addNode();
  //=======================================================
  /**
        * @brief Delete a node and all its adjacent edges in the graph
        * @warning That operation modify the array of nodes and the array of edges
        * and thus devalidate all iterators on it.
        * @warning That operation modify the array of neighboors of extrmities of edges, thus
        * it devalidates iterators on adjacency for the nodes at the extremities od the deleted edges.
        * @warning Orders of edges in the extremities of the deleted edges are affected
        * @remark: o(1)
        */
  void delNode(const node n);
  //=======================================================
  /**
       * @brief Add a new edge between src and tgt and return it
       * @warning That operation modify the array of neighboors of extrmities of edges, thus
       * it devalidates iterators on adjacency for the nodes at the extremities od the deleted edges.
       * @remark o(1)
       */
  edge addEdge(const node src, const node tgt);
  //=======================================================
  /**
        * @brief Delete an edge in the graph
        * @warning: That operation modify the array of edges
        * and thus devalidate all iterators on it.
        * @warning That operation modify the array of neighboors of extremities of the edge e, thus
        * it devalidates iterators on adjacency for the nodes at the extremities od the deleted edge.
        * @warning Orders of edges in the extremities of the deleted edge are affected
        * @remark o(1)
        */
  void delEdge(const edge e);
  //=======================================================
  /**
        * @brief Delete all adjacent edges (in/out) of a node
        * @warning: That operation modify the array of edges
        * and thus devalidate all iterators on it.
        * @warning That operation modify the array of neighboors of extremities of the edge e, thus
        * it devalidates iterators on adjacency for the nodes at the extremities od the deleted edge.
        * @warning Orders of edges in the extremities of the deleted edge are affected
        * @remark o(deg(V))
        * @todo test
        */
  void delEdges(const node n);
  //=======================================================
  /**
        * @brief Delete all edges in the graph
        * @warning: That operation modify the array of edges and all arrays of nodes
        * and thus devalidate all iterators, only graph nodes iterators are not affected.
        * @remark o(E + V)
        */
  void delAllEdges();
  //=======================================================
  /**
        * @brief Delete all nodes in the graph
        * @warning: That operation modify the array of edges and all arrays of nodes
        * and thus devalidate all iterators.
        * @remark o(E + V)
        */
  void delAllNodes();
  //=======================================================
  /**
      * @brief return the first extremity (considered as source if the graph is directed) of an edge
      * @remark o(1)
      */
  node source(const edge e) const;
  //=======================================================
  /**
      * @brief return the second extremity (considered as target if the graph is directed) of an edge
      * @remark o(1)
      */
  node target(const edge e) const;
  //=======================================================
  /**
        * @brief return the opposite node of n through edge e
        * @remark o(1)
        */
  node opposite(const edge e, const node n) const;
  //=======================================================
  /**
       * @brief Reverse an edge e, source become target and target become soure
       * @remark o(1)
       */
  void reverse(const edge e);
  //=======================================================
  /**
       * @brief change the source of an edge
       * @warning That operation modify the array of neighboors of extrmities of edges, thus
       * it devalidates iterators on adjacency for the nodes at the extremities of the modified edges and nodes.
       * @remark o(1)
       * \see setEnds
       */
  void setSource(const edge e, const node n);
  //=======================================================
  /**
       * @brief change the target of an edge
       * @warning That operation modify the array of neighboors of extrmities of edges, thus
       * it devalidates iterators on adjacency for the nodes at the extremities of the modified edges and nodes.
       * @remark o(1)
       * \see setEnds
       */
  void setTarget(const edge e, const node n);
  //=======================================================
  /**
       * @brief Return the extremities of an edge (src, target)
       * @remark o(1)
       */
  std::pair<node, node> ends(const edge e) const;
  //=======================================================
  /**
       * @brief Reconnect the edeg e to have the new given extremities
       * @warning That operation modify the array of neighboors of extrmities of edges, thus
       * it devalidates iterators on adjacency for the nodes at the extremities of the modified edges and nodes.
       * @remark o(1)
       */
  void setEnds(const edge e, const node src, const node tgt);
  //=======================================================
  /**
       * @brief Shuffle the array of graph nodes
       * @remark dependant of stl::random_shuffle algorithm (should be o(N))
       */
  void shuffleNodes();
  //=======================================================
  /**
       * @brief Shuffle the array of graph edges
       * @remark dependant of stl::random_shuffle algorithm (should be o(E))
       */
  void shuffleEdges();
  //=======================================================
  /**
       * @brief Sort all edges according to comparison functor given in parameter
       * if stable is true a stable sort algorithm is applied
       * Comparison should be an instance of a class wihch implements operator():
       * @remark dependant of stl::sort and stl::stable_sort algorithm (should be o(E log (E)))
       * @code
       *  class Compare {
       *  //return true if a < b
       *  bool operator()(const edge a, const edge b);
       *  };
       * @endcode
       * \warning that function is not compatible with the Tulip Graph API
       */
  template<typename Compare>
  void sortEdges(Compare cmp, bool stable = false) {
    if (stable)
      stable_sort(_edges.begin(), _edges.end(), cmp);
    else
      sort(_edges.begin(), _edges.end(), cmp);

    //recompute indices of edges
    for (unsigned int i = 0; i < _edges.size(); ++i) {
      _eData[_edges[i]]._edgesId = i;
    }
  }
  //=======================================================
  /**
       * @brief Sort all nodes according to comparison functor given in parameter
       * if stable is true a stable sort algorithm is applied
       * Comparison should be an instance of a class wihch implements operator():
       * @code
       *  class Compare {
       *  //return true if a < b
       *  bool operator()(const node a, const node b);
       *  };
       * @endcode
       * @remark dependant of stl::sort and stl::stable_sort algorithm (should be o(N log (N)))
       * \warning that function is not compatible with the Tulip Graph API
       */
  template<typename Compare >
  void sortNodes(Compare cmp, bool stable = false) {
    if (stable)
      stable_sort(_nodes.begin(), _nodes.end(), cmp);
    else
      sort(_nodes.begin(), _nodes.end(), cmp);

    //recompute indices of edges
    for (unsigned int i = 0; i < _nodes.size(); ++i) {
      _nData[_nodes[i]]._nodesId = i;
    }
  }
  //=======================================================
  /**
       * @brief return the position of an edge in the array of edges.
       * \warning that function is not compatible with the Tulip Graph API
       * @remark  o(1)
       */
  unsigned int edgePos(const edge e) const;
  //=======================================================
  /**
       * @brief return the position of a node in the array of nodes.
       * \warning that function is not compatible with the Tulip Graph API
       * @remark  o(1)
       */
  unsigned int nodePos(const node n) const;
  //=======================================================
  /**
        * @brief Swap two nodes in the array of graph nodes
        * @remark  o(1)
       * \warning that function is not compatible with the Tulip Graph API
        */
  void swap(const node a, const node b);
  //=======================================================
  /**
        * @brief Swap two edges in the array of graph edge
        * @remark  o(1)
       * \warning that function is not compatible with the Tulip Graph API
        */
  void swap(const edge a, const edge b);
  //=======================================================
  /**
        * @brief Create a new node array of type TYPE
        * NodesAttr can be copied in constant time it is just a pointer
        * NodesAttr is not a smart pointer it must be deleted with freeNodesAttribute
        * @remark  o(log(number of arrays) + new of a vector<TYPE> of size N)
        * \warning that function is not compatible with the Tulip Graph API
        */
  template<typename TYPE>
  void alloc(NodeProperty<TYPE> &prop) {
    ValArray<TYPE> *array = new ValArray<TYPE>(_nodes.size() + _freeNodes.size(), _nodes.capacity());
    _nodeArrays.insert(array);
    prop = NodeProperty<TYPE>(array, this);
  }
  //=======================================================
  /**
        * @brief Delete an Array from the set of node arrays
        * @warning all copy of the ValArray are no more valid (serious bug if they are used after)
        * @remark  o(log(number of arrays) + free of a vector<TYPE> of size N)
        * \warning that function is not compatible with the Tulip Graph API
        */
  template<typename TYPE>
  void free(NodeProperty<TYPE> array) {
    assert(_nodeArrays.find(array._array) != _nodeArrays.end());
    delete array._array;
    _nodeArrays.erase(array._array);
  }
  //=======================================================
  /**
      * @brief Create a new edge array of type TYPE
      * EdgesAttr can be copied in constant time it is just a pointer
      * EdgesAttr is not a smart pointer it must be deleted with freeEdgesAttribute
      * @remark  o(log(number of node arrays) + new of a vector<TYPE> of size E)
      * \warning that function is not compatible with the Tulip Graph API
      */
  template<typename TYPE>
  void alloc(EdgeProperty<TYPE> &prop) {
    ValArray<TYPE> *array = new ValArray<TYPE>(_edges.size() + _freeEdges.size(), _edges.capacity());
    _edgeArrays.insert(array);
    prop = EdgeProperty<TYPE>(array, this);
  }
  //=======================================================
  /**
        * @brief Delete an Array from the set of edge arrays
        * @warning all copy of the ValArray are no more valid (serious bug if they are used after)
        * @remark  o(log(number of edge arrays) + free of a vector<TYPE> of size E)
        * \warning that function is not compatible with the Tulip Graph API
        */
  template<typename TYPE>
  void free(EdgeProperty<TYPE> array) {
    assert(_edgeArrays.find(array._array) != _edgeArrays.end());
    delete array._array;
    _edgeArrays.erase(array._array);
  }
  //=======================================================
  /**
        * @brief Return a const reference on the vector of adjacent nodes of n
        *
        * It is the fastest way to access to node adjacency, Iterators are 25% slower.
        * \warning code that use that function won't be compatible with Tulip Graph API
        *
        * @remark o(1)
        * \see getInOutNodes
        * \see getInNodes
        * \see getOutNodes
        */
  const std::vector<node>& adj(const node n) const;
  //=======================================================
  /**
        * @brief Return a const reference on the vector of adjacent edges of n
        *
        * It is the fastest way to access to edge adjacency, Iterators are 25% slower.
        * \warning code that use that function won't be compatible with Tulip Graph API
        *
        * @remark o(1)
        * \see getInOutEdges
        * \see getInEdges
        * \see getOutEdges
        */
  const std::vector<edge>& star(const node n) const;
  //=======================================================
  /**
        * @brief Return a const reference on the vector of nodes of the graph
        * It is the fastest way to access to edge adjacency, Iterators are 25% slower.
        * \warning code that use that function won't be compatible with Tulip Graph API
        * @remark o(1)
        */
  const std::vector<node>& nodes() const;
  //=======================================================
  /**
        * @brief Return a const reference on the vector of edges of the graph
        * It is the fastest way to access to edge adjacency, Iterators are 25% slower.
        * \warning code that use that function won't be compatible with Tulip Graph API
        * @remark o(1)
        */
  const std::vector<edge>& edges() const;
  //=======================================================
#ifndef NDEBUG
  /**
        * these two function are used internally to insure that property has been allocated in debug mode
        * @warning never used these function directly even in debug mode !!!
        */
  template<typename TYPE>
  bool isNodeAttr(ValArray<TYPE> *array) {
    return (_nodeArrays.find(array) != _nodeArrays.end());
  }
  template<typename TYPE>
  bool isEdgeAttr(ValArray<TYPE> *array) {
    return (_edgeArrays.find(array) != _edgeArrays.end());
  }
#endif
  //=============================================================
  /**
        * output the graph in a very simple way for debugging
        */
  void dump() const;
  //=============================================================
  /**
        * internal function to test the integrity of the graph
        */
  void integrityTest();

private:

  struct _iNodes {
    _iNodes(unsigned int id = UINT_MAX): _nodesId(id), _outdeg(0) {
    }

    void clear() {
      _outdeg = 0;
      _adjt.resize(0);
      _adjn.resize(0);
      _adje.resize(0);
    }

    void addEdge(bool t, node n, edge e) {
      _adjt.push_back(t);
      _adjn.push_back(n);
      _adje.push_back(e);
    }

    unsigned int _nodesId; /** index of a node in the _nodes vector*/
    unsigned int _outdeg;  /** out degree of nodes */
    std::vector<bool> _adjt; /** orientation of the edge, used to separate in and out edges/nodes */
    std::vector<node> _adjn; /** inout nodes*/
    std::vector<edge> _adje; /** inout edges*/
  };

  struct _iEdges {
    unsigned int _edgesId; /** index of a node in the _edges vector*/
    std::pair<node, node> _edgeExtremities; /** source and target of an edge */
    std::pair<unsigned int, unsigned int> _edgeExtremitiesPos; /** source and target of an edge */
  };

  std::vector<_iNodes> _nData; /** internal storage of nodes */
  std::vector<_iEdges> _eData; /** internal storage of edges */

  std::vector< node > _nodes; /** vector of nodes element of the graph */
  std::vector< edge > _edges; /** vector of edges element of the graph */

  std::vector<node> _freeNodes; /** vector of nodes that has been deleted and that can be reused */
  std::vector<edge> _freeEdges; /** vector of edges that has been deleted and that can be reused */

  std::set<ValArrayInterface *> _nodeArrays; /** set of all node properties allocated on that graph */
  std::set<ValArrayInterface *> _edgeArrays; /** set of all edge properties allocated on that graph */

  //=======================================================
  /**
       * internal function to break the program and output debug information during
       * integrity test.
       * @TODO hide that function in the .cpp file
       */
  void testCond(std::string str, bool b);
  //=======================================================
  /**
        * internal function to adjust size of node properties when graph is modified
        */
  void addNodeToArray(node n);
  //=======================================================
  /**
        * internal function to adjust size of edge properties when graph is modified
        */
  void addEdgeToArray(edge e);
  //=======================================================
  /**
        * internal function to remove an edge
        */
  void removeEdge(edge e);
  //=======================================================
  /**
        * Internal function to remove the edge e in the adjacency list of n
        */
  void moveEdge(node n, unsigned int a, unsigned int b);
  /**
        * Internal function tp remove the edge e in the adjacency list of n
        */
  void partialDelEdge(node n, edge e);
  //=======================================================
};


#ifndef NDEBUG //these two function are used to insure that property has been allocated in debug mode
template <typename TYPE>
bool NodeProperty<TYPE>::isValid() const {
  if (this->_graph == 0) return false;

  if (this->_array == 0) return false;

  return this->_graph->isNodeAttr(this->_array);
}

template <typename TYPE>
bool EdgeProperty<TYPE>::isValid() const {
  if (this->_graph == 0) return false;

  if (this->_array == 0) return false;

  return this->_graph->isEdgeAttr(this->_array);
}
#endif
}
#endif // VECTORGRAPH_H
///@endcond