tree.hpp

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#ifndef STRINGTREE_H
#define STRINGTREE_H
 
#include <vector>
#include <deque>
#include <iostream>
#include <memory>
 
#include "rosx_introspection/builtin_types.hpp"
 
namespace RosMsgParser
{
 
namespace details
{
 
template <typename T>
class TreeNode
{
public:
  typedef std::vector<TreeNode> ChildrenVector;  // dangerous because of pointer
                                                 // invalidation (but faster)
 
  TreeNode(const TreeNode* parent);
 
  const TreeNode* parent() const
  {
    return _parent;
  }
 
  const T& value() const
  {
    return _value;
  }
  void setValue(const T& value)
  {
    _value = value;
  }
 
  const ChildrenVector& children() const
  {
    return _children;
  }
  ChildrenVector& children()
  {
    return _children;
  }
 
  const TreeNode* child(size_t index) const
  {
    return &(_children[index]);
  }
  TreeNode* child(size_t index)
  {
    return &(_children[index]);
  }
 
  TreeNode* addChild(const T& child);
 
  bool isLeaf() const
  {
    return _children.empty();
  }
 
private:
  const TreeNode* _parent = nullptr;
  T _value;
  ChildrenVector _children;
};
 
template <typename T>
class Tree
{
public:
  Tree() : _root(new TreeNode<T>(nullptr))
  {
  }
 
  template <typename Vect>
  const TreeNode<T>* find(const Vect& concatenated_values, bool partial_allowed = false);
 
  const TreeNode<T>* croot() const
  {
    return _root.get();
  }
 
  TreeNode<T>* root()
  {
    return _root.get();
  }
 
  friend std::ostream& operator<<(std::ostream& os, const Tree& _this)
  {
    _this.print_impl(os, _this.croot(), 0);
    return os;
  }
 
  template <class Functor>
  void visit(Functor& func, const TreeNode<T>* node) const
  {
    func(node);
    for (auto child : node->children())
    {
      visit(func, &child);
    }
  }
 
private:
  void print_impl(std::ostream& os, const TreeNode<T>* node, int indent) const;
 
  std::unique_ptr<TreeNode<T>> _root;
};
 
//-----------------------------------------
 
template <typename T>
inline std::ostream& operator<<(
    std::ostream& os, const std::pair<const TreeNode<T>*, const TreeNode<T>*>& tail_head)
{
  const TreeNode<T>* tail = tail_head.first;
  const TreeNode<T>* head = tail_head.second;
 
  if (!head)
    return os;
 
  const TreeNode<T>* array[64];
  int index = 0;
  array[index++] = head;
 
  while (!head || head != tail)
  {
    head = head->parent();
    array[index++] = head;
  };
  array[index] = nullptr;
  index--;
 
  while (index >= 0)
  {
    if (array[index])
    {
      os << array[index]->value();
    }
    if (index > 0)
      os << ".";
    index--;
  }
  return os;
}
 
template <typename T>
inline void Tree<T>::print_impl(std::ostream& os, const TreeNode<T>* node,
                                int indent) const
{
  for (int i = 0; i < indent; i++)
    os << " ";
  os << node->value() << std::endl;
 
  for (const auto& child : node->children())
  {
    print_impl(os, &child, indent + 3);
  }
}
 
template <typename T>
inline TreeNode<T>::TreeNode(const TreeNode* parent) : _parent(parent)
{
}
 
template <typename T>
inline TreeNode<T>* TreeNode<T>::addChild(const T& value)
{
  assert(_children.capacity() > _children.size());
  _children.emplace_back(this);
  _children.back().setValue(value);
  return &_children.back();
}
 
template <typename T>
template <typename Vect>
inline const TreeNode<T>* Tree<T>::find(const Vect& concatenated_values,
                                        bool partial_allowed)
{
  TreeNode<T>* node = &_root;
 
  for (const auto& value : concatenated_values)
  {
    bool found = false;
    for (auto& child : (node->children()))
    {
      if (child.value() == value)
      {
        node = &(child);
        found = true;
        break;
      }
    }
    if (!found)
      return nullptr;
  }
 
  if (partial_allowed || node->children().empty())
  {
    return node;
  }
  return nullptr;
}
 
}  // namespace details
 
}  // namespace RosMsgParser
 
#endif  // STRINGTREE_H