MeshFacadeIterators.h

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/*
   For more information, please see: http://software.sci.utah.edu

   The MIT License

   Copyright (c) 2009 Scientific Computing and Imaging Institute,
   University of Utah.

   
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/// @todo Documentation Core/Datatypes/Mesh/MeshFacadeIterators.h

#ifndef CORE_DATATYPES_MESH_FACADE_ITERATORS_H
#define CORE_DATATYPES_MESH_FACADE_ITERATORS_H 

#include <boost/iterator/iterator_facade.hpp>
#include <Core/Utils/Exception.h>
#include <Core/GeometryPrimitives/Point.h>
#include <Core/Datatypes/Mesh/share.h>

namespace SCIRun {
namespace Core {
namespace Datatypes {
  
  /*
    IDEA: Mesh iterators should iterate over entire values, not just indexes, producing values on demand. 
    A "SmartIndex" for the mesh.
    E.G. for LatVols:
    class SmartNodeIterator : public std::iterator<std::forward_iterator_tag, SmartIndex<Mesh::index_type,Point> >
    class SmartEdgeIterator : public std::iterator<std::forward_iterator_tag, SmartIndex<Mesh::index_type,Point[2]> >
    class SmartFaceIterator : public std::iterator<std::forward_iterator_tag, SmartIndex<Mesh::index_type,Point[4],SmartIndex<Edge>[4]> >
  */

  /// @todo: Being conservative with mesh synchronization flags until more
  // synchronize infrastructure is implemented and tested,
  // so clear_synchronization() is always called after synchronize and operation
  // that requires synchronize to be called.
  template <class VirtualMeshType, template <typename> class MeshComponent>
  class SmartMeshIterator : public boost::iterator_facade<SmartMeshIterator<VirtualMeshType, MeshComponent>, MeshComponent<VirtualMeshType>, boost::bidirectional_traversal_tag>
  {
  public:
    /// @todo: need to look up pattern for creating "end" iterators.
    explicit SmartMeshIterator(VirtualMeshType* vmesh = 0, bool isEnd = false) : iter_(0), vmesh_(vmesh), current_(vmesh)
    {
      ENSURE_NOT_NULL(vmesh, "virtual mesh");
      if (!isEnd)
      {
        vmesh_->begin(iter_);
      }
      else
      {
        /// @todo: need to split out that Synchronize enum
        vmesh_->synchronize(/*Mesh::EDGES_E*/ 2);
        vmesh_->end(iter_);
      }
      current_.setIndex(*iter_);
    }
  private:
    friend class boost::iterator_core_access;

    void increment() { ++iter_; }
    void decrement() { --iter_; }

    bool equal(const SmartMeshIterator<VirtualMeshType, MeshComponent>& other) const
    {
      return this->vmesh_ == other.vmesh_ 
        && this->iter_ == other.iter_;
    }

    MeshComponent<VirtualMeshType>& dereference() const
    { 
      current_.setIndex(*iter_);
      return current_; 
    }

    typename MeshComponent<VirtualMeshType>::iterator iter_;
    VirtualMeshType* vmesh_;
    mutable MeshComponent<VirtualMeshType> current_;
  };

  /// @todo: templatize with traits and stuff. for now, a specialized version for edges.
  template <class VirtualMeshType>
  class EdgeInfo
  {
  public:
    typedef typename VirtualMeshType::Edge::iterator iterator;
    enum
    {
      sync_enum = 2
    };
    explicit EdgeInfo(VirtualMeshType* mesh) : index_(0), vmesh_(mesh) 
    {
      /// @todo: need to split out that Synchronize enum
      vmesh_->synchronize(/*Mesh::EDGES_E*/ sync_enum);
    }
    void setIndex(typename VirtualMeshType::Edge::index_type i) { index_ = i; }

    typename VirtualMeshType::Edge::index_type index() const { return index_; }
    typename VirtualMeshType::Node::array_type nodeIndices() const
    {
      typename VirtualMeshType::Node::array_type nodesFromEdge(2);
      vmesh_->get_nodes(nodesFromEdge, index_);

      return nodesFromEdge;
    }

    std::vector<Geometry::Point> nodePoints() const 
    {
      auto indices = nodeIndices();
      std::vector<Geometry::Point> ps(2);
      for (size_t i = 0; i < ps.size(); ++i)
        vmesh_->get_point(ps[i], indices[i]);
      
      return ps;
    }
  private:
    typename VirtualMeshType::Edge::index_type index_;
    VirtualMeshType* vmesh_;
  };

  template <typename VirtualMeshType>
  struct SmartEdgeIterator
  {
    typedef SmartMeshIterator<VirtualMeshType, EdgeInfo> Type;
  };

  template <class VirtualMeshType>
  class FaceInfo 
  {
  public:
    typedef typename VirtualMeshType::Face::iterator iterator;
    enum
    {
      sync_enum = 4
    };
    explicit FaceInfo(VirtualMeshType* mesh) : index_(0), vmesh_(mesh) 
    {
      vmesh_->synchronize(/*Mesh::FACES_E*/ sync_enum);
    }
    void setIndex(typename VirtualMeshType::Face::index_type i) { index_ = i; }

    typename VirtualMeshType::Face::index_type index() const { return index_; }
    typename VirtualMeshType::Node::array_type nodeIndices() const
    {
      typename VirtualMeshType::Node::array_type nodesFromFace(4);
      vmesh_->get_nodes(nodesFromFace, index_);
      return nodesFromFace;
    }
    std::vector<Geometry::Point> nodePoints() const 
    {
      auto indices = nodeIndices();
      std::vector<Geometry::Point> ps(4);
      for (size_t i = 0; i < ps.size(); ++i)
        vmesh_->get_point(ps[i], indices[i]);
      return ps;
    }
    typename VirtualMeshType::Edge::array_type edgeIndices() const
    {
      typename VirtualMeshType::Edge::array_type edgesFromFace(4);
      vmesh_->get_edges(edgesFromFace, index_);
      return edgesFromFace;
    }
  private:
    typename VirtualMeshType::Face::index_type index_;
    VirtualMeshType* vmesh_;
  };

  template <typename VirtualMeshType>
  struct SmartFaceIterator
  {
    typedef SmartMeshIterator<VirtualMeshType, FaceInfo> Type;
  };

  template <class VirtualMeshType>
  class NodeInfo 
  {
  public:
    typedef typename VirtualMeshType::Node::iterator iterator;
    enum
    {
      sync_enum = 1 << 8
    };
    explicit NodeInfo(VirtualMeshType* mesh) : synched_(false), index_(0), vmesh_(mesh) {}
    void setIndex(typename VirtualMeshType::Node::index_type i) { index_ = i; }

    typename VirtualMeshType::Node::index_type index() const { return index_; }
    Geometry::Point point() const 
    {
      Geometry::Point p;
      vmesh_->get_point(p, index_);
      return p;
    }
    typename VirtualMeshType::Edge::array_type edgeIndices() const
    {
      if (!synched_)
      {
        /// @todo: need to split out that Synchronize enum
        vmesh_->synchronize(/*Mesh::NODE_NEIGHBORS_E*/sync_enum);
        synched_ = true;
      }
      typename VirtualMeshType::Edge::array_type edgesFromNode(6);
      vmesh_->get_edges(edgesFromNode, index_);
      return edgesFromNode;
    }
  private:
    mutable bool synched_;
    typename VirtualMeshType::Node::index_type index_;
    VirtualMeshType* vmesh_;
  };

  template <typename VirtualMeshType>
  struct SmartNodeIterator
  {
    typedef SmartMeshIterator<VirtualMeshType, NodeInfo> Type;
  };
  
}}}

#endif