branch_iter_ind.hh

// Copyright (C) 2007, 2008, 2009 EPITA Research and Development Laboratory (LRDE)
//
// This file is part of Olena.
//
// Olena is free software: you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free
// Software Foundation, version 2 of the License.
//
// Olena 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.
//
// You should have received a copy of the GNU General Public License
// along with Olena.  If not, see <http://www.gnu.org/licenses/>.
//
// As a special exception, you may use this file as part of a free
// software project without restriction.  Specifically, if other files
// instantiate templates or use macros or inline functions from this
// file, or you compile this file and link it with other files to produce
// an executable, this file does not by itself cause the resulting
// executable to be covered by the GNU General Public License.  This
// exception does not however invalidate any other reasons why the
// executable file might be covered by the GNU General Public License.

#ifndef MLN_UTIL_BRANCH_ITER_IND_HH
# define MLN_UTIL_BRANCH_ITER_IND_HH

# include <stack>
# include <mln/util/tree.hh>

namespace mln
{

  namespace util
  {
    template<typename T>
    struct bi_elt
    {
      typedef std::vector< util::tree_node<T>* > child_list;

      bi_elt(child_list* list)
        : list_(list),
          previous_(0),
          pos_(-1) {}

      child_list* list_;
      util::tree_node<T>* previous_;
      int pos_;
    };

    template <typename T>
    class branch_iter_ind
    {
    public:
      branch_iter_ind(branch<T> branch);

      operator util::tree_node<T>&() const;
      util::tree_node<T>& operator *();

      bool is_valid() const;

      void invalidate();

      void start();

      void next();

      unsigned deepness() const;

    private:
      util::branch<T> branch_;

      std::stack< bi_elt<T> > s_;

      util::tree_node<T>* n_;
    };

# ifndef MLN_INCLUDE_ONLY


    template <typename T>
    inline
    branch_iter_ind<T>::branch_iter_ind(branch<T> branch)
      : branch_(branch)
    {
      invalidate();
    }

    template <typename T>
    inline
    branch_iter_ind<T>::operator util::tree_node<T>&() const
    {
      mln_assertion(n_);
      return *n_;
    }

    template <typename T>
    inline
    util::tree_node<T>&
    branch_iter_ind<T>::operator*()
    {
      mln_assertion(n_);
      return *n_;
    }

    template <typename T>
    inline
    unsigned
    branch_iter_ind<T>::deepness() const
    {
      mln_assertion(is_valid());
      unsigned i = 0;
      tree_node<T>* p = n_;
      while (p)
      {
        p = p->parent();
        i++;
      }
      return i;
    }

    template <typename T>
    inline
    bool
    branch_iter_ind<T>::is_valid() const
    {
      return n_ != 0;
    }

    template <typename T>
    inline
    void
    branch_iter_ind<T>::invalidate()
    {
      n_ = 0;
    }


    template <typename T>
    inline
    void
    branch_iter_ind<T>::start()
    {
      s_.push(bi_elt<T>(&branch_.apex().children()));

      n_ = &branch_.apex();
    }

    template <typename T>
    inline
    void
    branch_iter_ind<T>::next()
    {
      // First : list of children.
      // Second : i;

      if (s_.size() == 0)
        invalidate();
      else
      {
        s_.top().pos_++;
        if (s_.top().list_->size() == (unsigned)s_.top().pos_)
        {
          s_.pop();
          next();
          return;
        }
        else
        {
          mln_assertion(s_.top().list_->size() > (unsigned)s_.top().pos_);
          if (s_.top().previous_ != 0)
            mln_assertion(s_.top().previous_ == (*(s_.top().list_))[s_.top().pos_ - 1]);

          n_ = (*(s_.top().list_))[s_.top().pos_];
          s_.top().previous_ = n_;

          if (!n_)
          {
            next();
            return;
          }

          mln_assertion(n_);
          if (n_->children().size() > 0)
          {
            s_.push(bi_elt<T>(&n_->children()));
          }
          return;
        }
      }
    }

# endif // ! MLN_INCLUDE_ONLY


  }

} // end of namespace mln


#endif // ! MLN_UTIL_BRANCH_ITER_IND_HH