treedata.hh

// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
// vi: set et ts=4 sw=2 sts=2:
#ifndef DUNE_FUNCTIONS_COMMON_TREEDATA_HH
#define DUNE_FUNCTIONS_COMMON_TREEDATA_HH
 
#include <memory>
 
#include <dune/common/shared_ptr.hh>
 
#include <dune/typetree/pairtraversal.hh>
 
#include <dune/functions/gridfunctions/gridviewentityset.hh>
#include <dune/functions/gridfunctions/gridfunction.hh>
 
namespace Dune {
namespace Functions {
 
template<class SimpleNodeVisitorImp, bool leafOnly>
struct UniformNodeVisitor :
    public TypeTree::TreeVisitor,
    public TypeTree::DynamicTraversal
{
    // This is only enabled, if we want to incorporate inner nodes.
    // Checking leafOnly would be sufficient, but for SFINAE the
    // the enable_if condition must depend on the template parameter.
    template<typename Node, typename TreePath,
        typename std::enable_if<(not leafOnly) and (not Node::isLeaf), int>::type = 0>
    void pre(Node& node, TreePath treePath)
    {
      static_cast<SimpleNodeVisitorImp*>(this)->apply(node, treePath);
    }
 
    template<typename Node, typename TreePath,
        typename std::enable_if<(leafOnly) and (not Node::isLeaf), int>::type = 0>
    void pre(Node& node, TreePath treePath)
    {}
 
    template<typename Node, typename TreePath>
    void leaf(Node& node, TreePath treePath)
    {
      static_cast<SimpleNodeVisitorImp*>(this)->apply(node, treePath);
    }
};
 
 
 
template<class T, template<class> class ND, bool LO>
class TreeData
{
 
public:
 
  using Tree = T;
 
  using size_type = typename Tree::size_type;
 
  static const bool leafOnly = LO;
 
  template<class Node>
  using NodeData = ND<Node>;
 
protected:
  using RawContainer = std::vector<void*>;
 
 
  // Since we can generate the node data type only if
  // we know the type of the node, we have to do
  // initialization, copy, and destruction via a
  // tree traversal. Once we can use C++14 this can
  // be written in a much easier and more selfcontained
  // ways using generic lambda functions.
  // Until then we need explicite visitor classes for
  // each operation.
 
  struct InitVisitor :
    public UniformNodeVisitor<InitVisitor, leafOnly>
  {
    InitVisitor(RawContainer& data) :
      data_(data)
    {}
 
    template<typename Node, typename TreePath>
    void apply(Node& node, TreePath treePath)
    {
      auto&& index = node.treeIndex();
      if (data_.size() < index+1)
        data_.resize(index+1, nullptr);
      data_[index] = new NodeData<Node>;
    }
 
 
    RawContainer& data_;
  };
 
  struct DestroyVisitor :
    public UniformNodeVisitor<DestroyVisitor, leafOnly>
  {
    DestroyVisitor(RawContainer& data) :
      data_(data)
    {}
 
    template<typename Node, typename TreePath>
    void apply(Node& node, TreePath treePath)
    {
      auto&& index = node.treeIndex();
      auto p = (NodeData<Node>*)(data_[index]);
      delete p;
      data_[index] = nullptr;
    }
 
    RawContainer& data_;
  };
 
  struct CopyVisitor :
    public UniformNodeVisitor<CopyVisitor, leafOnly>
  {
    CopyVisitor(TreeData& thisTD, const TreeData& otherTD) :
      thisTD_(thisTD),
      otherTD_(otherTD)
    {}
 
    template<typename Node, typename TreePath>
    void apply(Node& node, TreePath treePath)
    {
      thisTD_[node] = otherTD_[node];
    }
 
    TreeData& thisTD_;
    const TreeData& otherTD_;
  };
 
public:
 
  TreeData() :
    tree_(nullptr)
  {}
 
  void init(const Tree& tree)
  {
    if (tree_)
      destroy();
    tree_ = &tree;
    TypeTree::applyToTree(*tree_, InitVisitor(data_));
  }
 
  TreeData(const TreeData& other) :
    tree_(other.tree_)
  {
    TypeTree::applyToTree(*tree_, InitVisitor(data_));
    TypeTree::applyToTree(*tree_, CopyVisitor(*this, other));
  }
 
  TreeData& operator=(const TreeData& other)
  {
    if (tree_)
      TypeTree::applyToTree(*tree_, DestroyVisitor(data_));
    tree_ = other.tree_;
    TypeTree::applyToTree(*tree_, CopyVisitor(*this, other));
    return *this;
  }
 
  void destroy()
  {
    if (tree_)
      TypeTree::applyToTree(*tree_, DestroyVisitor(data_));
    tree_ = nullptr;
  }
 
  ~TreeData()
  {
    if (tree_)
      TypeTree::applyToTree(*tree_, DestroyVisitor(data_));
  }
 
  template<class Node>
  NodeData<Node>& operator[](const Node& node)
  {
    return *(NodeData<Node>*)(data_[node.treeIndex()]);
  }
 
  template<class Node>
  const NodeData<Node>& operator[](const Node& node) const
  {
    return *(NodeData<Node>*)(data_[node.treeIndex()]);
  }
 
protected:
 
  const Tree* tree_;
  RawContainer data_;
};
 
 
 
} // namespace Functions
} // namespace Dune
 
#endif // DUNE_FUNCTIONS_COMMON_TREEDATA_HH