/****************************************************************************
 * Copyright (C) 2011 EPAM Systems
 * 
 * This file is part of Indigo toolkit.
 * 
 * This file may be distributed and/or modified under the terms of the
 * GNU General Public License version 3 as published by the Free Software
 * Foundation and appearing in the file LICENSE.GPL included in the
 * packaging of this file.
 * 
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 ***************************************************************************/

#ifndef __graph_fast_access_h__
#define __graph_fast_access_h__

#include "base_cpp/array.h"
#include "graph/graph.h"

namespace indigo {

class Graph;

class GraphFastAccess
{
public:
   void setGraph (Graph &g);

   int* prepareVertices (int &count);
   int  getVertex (int idx); // unsafe
   int  vertexCount ();

   // Prepare both nei vertices and edges list. Runs faster then 
   // preparing them one by one.
   void prepareVertexNeiVerticesAndEdges (int v);
   // Returns nei vertices and nei edges for specified vertex
   // Numeration is coherent
   // Note: pointer might become invalid after preparing calls for 
   // different vertices. In this case use prepareVertexNeiVertices/getVertexNeiVertiex.
   int* getVertexNeiVertices (int v, int &count);
   int* getVertexNeiEdges (int v, int &count);

   // Returns vertex identifier that can be used in getVertexNeiVertiex
   int prepareVertexNeiVertices (int v, int &count);
   // Returns neighbor vertex for the specified 
   // vertex id (returned by prepareVertexNeiVertices)
   int getVertexNeiVertiex (int v_id, int index);

   int findEdgeIndex (int v1, int v2);

   void prepareEdges ();
   const Edge& getEdge (int e);
   const Edge* getEdges ();

private:
   Graph *_g;
   
   Array<int> _vertices;

   struct VertexNeiBlock
   {
      int v_begin, v_count;
      int e_begin, e_count;
   };
   Array<VertexNeiBlock> _vertices_nei;
   Array<int> _nei_vertices_data, _nei_edges_data;

   Array<Edge> _edges;
};

}

#endif // __graph_fast_access_h__