bst_iter.h

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// vi:ft=cpp
/*
 * (c) 2008-2009 Alexander Warg <warg@os.inf.tu-dresden.de>,
 *               Carsten Weinhold <weinhold@os.inf.tu-dresden.de>
 *     economic rights: Technische Universität Dresden (Germany)
 *
 * License: see LICENSE.spdx (in this directory or the directories above)
 */
 
#pragma once
 
#include "bst_base.h"
 
namespace cxx { namespace Bits {
 
template< typename Node, typename Node_op >
class __Bst_iter_b
{
protected:
  typedef Direction Dir;
  Node const *_n;   
  Node const *_r;   
 
  __Bst_iter_b() : _n(0), _r(0) {}
 
  __Bst_iter_b(Node const *t)
    : _n(t), _r(_n)
  { _downmost(); }
 
  __Bst_iter_b(Node const *t, Node const *r)
    : _n(t), _r(r)
  {}
 
  inline void _downmost();
 
  inline void inc();
 
public:
  bool operator == (__Bst_iter_b const &o) const { return _n == o._n; }
  bool operator != (__Bst_iter_b const &o) const { return _n != o._n; }
};
 
template< typename Node, typename Node_type, typename Node_op >
class __Bst_iter : public __Bst_iter_b<Node, Node_op>
{
private:
  typedef __Bst_iter_b<Node, Node_op> Base;
 
  using Base::_n;
  using Base::_r;
  using Base::inc;
 
public:
  __Bst_iter() {}
 
  __Bst_iter(Node const *t) : Base(t) {}
  __Bst_iter(Node const *t, Node const *r) : Base(t, r) {}
 
//  template<typename Key2>
  __Bst_iter(Base const &o) : Base(o) {}
 
  Node_type &operator * () const { return *const_cast<Node *>(_n); }
  Node_type *operator -> () const { return const_cast<Node *>(_n); }
  __Bst_iter &operator ++ () { inc(); return *this; }
  __Bst_iter &operator ++ (int)
  { __Bst_iter tmp = *this; inc(); return tmp; }
};
 
 
//----------------------------------------------------------------------------
/* IMPLEMENTATION: __Bst_iter_b */
 
template< typename Node, typename Node_op>
inline
void __Bst_iter_b<Node, Node_op>::_downmost()
{
  while (_n)
    {
      Node *n = Node_op::child(_n, Dir::L);
      if (n)
  _n = n;
      else
  return;
    }
}
 
template< typename Node, typename Node_op>
void __Bst_iter_b<Node, Node_op>::inc()
{
  if (!_n)
    return;
 
  if (_n == _r)
    {
      _r = _n = Node_op::child(_r, Dir::R);
      _downmost();
      return;
    }
 
  if (Node_op::child(_n, Dir::R))
    {
      _n = Node_op::child(_n, Dir::R);
      _downmost();
      return;
    }
 
  Node const *q = _r;
  Node const *p = _r;
  while (1)
    {
      if (Node_op::cmp(_n, q))
  {
    p = q;
    q = Node_op::child(q, Dir::L);
  }
      else if (_n == q || Node_op::child(q, Dir::R) == _n)
  {
    _n = p;
    return;
  }
      else
  q = Node_op::child(q, Dir::R);
    }
}
 
}}