splay_fn_imps.hpp   [plain text]

// -*- C++ -*-

// Copyright (C) 2005, 2006 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library 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; either version 2, or (at your option) any later
// version.

// This library 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 this library; see the file COPYING.  If not, write to
// the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
// MA 02111-1307, USA.

// As a special exception, you may use this file as part of a free
// software library 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.

// Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.

// Permission to use, copy, modify, sell, and distribute this software
// is hereby granted without fee, provided that the above copyright
// notice appears in all copies, and that both that copyright notice
// and this permission notice appear in supporting documentation. None
// of the above authors, nor IBM Haifa Research Laboratories, make any
// representation about the suitability of this software for any
// purpose. It is provided "as is" without express or implied
// warranty.

/**
 * @file splay_fn_imps.hpp
 * Contains an implementation class for splay_tree_.
 */

PB_DS_CLASS_T_DEC
void
PB_DS_CLASS_C_DEC::
splay(node_pointer p_nd)
{
  while (p_nd->m_p_parent != base_type::m_p_head)
    {
#ifdef _GLIBCXX_DEBUG
      {
	node_pointer p_head = base_type::m_p_head;
	assert_special_imp(p_head);
      }
#endif

      _GLIBCXX_DEBUG_ONLY(base_type::assert_node_consistent(p_nd);)

        if (p_nd->m_p_parent->m_p_parent == base_type::m_p_head)
	  {
            base_type::rotate_parent(p_nd);
            _GLIBCXX_DEBUG_ASSERT(p_nd == this->m_p_head->m_p_parent);
	  }
        else
	  {
            const node_pointer p_parent = p_nd->m_p_parent;
            const node_pointer p_grandparent = p_parent->m_p_parent;

#ifdef _GLIBCXX_DEBUG
            const size_type total =
	      base_type::recursive_count(p_grandparent);
            _GLIBCXX_DEBUG_ASSERT(total >= 3);
#endif 

            if (p_parent->m_p_left == p_nd && 
		p_grandparent->m_p_right == p_parent)
	      splay_zig_zag_left(p_nd, p_parent, p_grandparent);
            else if (p_parent->m_p_right == p_nd && 
		     p_grandparent->m_p_left == p_parent)
	      splay_zig_zag_right(p_nd, p_parent, p_grandparent);
            else if (p_parent->m_p_left == p_nd && 
		     p_grandparent->m_p_left == p_parent)
	      splay_zig_zig_left(p_nd, p_parent, p_grandparent);
            else
	      splay_zig_zig_right(p_nd, p_parent, p_grandparent);
            _GLIBCXX_DEBUG_ASSERT(total ==this->recursive_count(p_nd));
	  }

      _GLIBCXX_DEBUG_ONLY(base_type::assert_node_consistent(p_nd);)
  }
}

PB_DS_CLASS_T_DEC
inline void
PB_DS_CLASS_C_DEC::
splay_zig_zag_left(node_pointer p_nd, node_pointer p_parent, 
		   node_pointer p_grandparent)
{
  _GLIBCXX_DEBUG_ASSERT(p_parent == p_nd->m_p_parent);
  _GLIBCXX_DEBUG_ASSERT(p_grandparent == p_parent->m_p_parent);

  _GLIBCXX_DEBUG_ONLY(base_type::assert_node_consistent(p_grandparent);)

  _GLIBCXX_DEBUG_ASSERT(p_parent->m_p_left == p_nd && 
		        p_grandparent->m_p_right == p_parent);

  splay_zz_start(p_nd, p_parent, p_grandparent);

  node_pointer p_b = p_nd->m_p_right;
  node_pointer p_c = p_nd->m_p_left;

  p_nd->m_p_right = p_parent;
  p_parent->m_p_parent = p_nd;

  p_nd->m_p_left = p_grandparent;
  p_grandparent->m_p_parent = p_nd;

  p_parent->m_p_left = p_b;
  if (p_b != NULL)
    p_b->m_p_parent = p_parent;

  p_grandparent->m_p_right = p_c;
  if (p_c != NULL)
    p_c->m_p_parent = p_grandparent;

  splay_zz_end(p_nd, p_parent, p_grandparent);
}

PB_DS_CLASS_T_DEC
inline void
PB_DS_CLASS_C_DEC::
splay_zig_zag_right(node_pointer p_nd, node_pointer p_parent, 
		    node_pointer p_grandparent)
{
  _GLIBCXX_DEBUG_ASSERT(p_parent == p_nd->m_p_parent);
  _GLIBCXX_DEBUG_ASSERT(p_grandparent == p_parent->m_p_parent);

  _GLIBCXX_DEBUG_ONLY(base_type::assert_node_consistent(p_grandparent);)

  _GLIBCXX_DEBUG_ASSERT(p_parent->m_p_right == p_nd && 
	  	        p_grandparent->m_p_left == p_parent);

  splay_zz_start(p_nd, p_parent, p_grandparent);

  node_pointer p_b = p_nd->m_p_left;
  node_pointer p_c = p_nd->m_p_right;

  p_nd->m_p_left = p_parent;
  p_parent->m_p_parent = p_nd;

  p_nd->m_p_right = p_grandparent;
  p_grandparent->m_p_parent = p_nd;

  p_parent->m_p_right = p_b;
  if (p_b != NULL)
    p_b->m_p_parent = p_parent;

  p_grandparent->m_p_left = p_c;
  if (p_c != NULL)
    p_c->m_p_parent = p_grandparent;

  splay_zz_end(p_nd, p_parent, p_grandparent);
}

PB_DS_CLASS_T_DEC
inline void
PB_DS_CLASS_C_DEC::
splay_zig_zig_left(node_pointer p_nd, node_pointer p_parent, 
		   node_pointer p_grandparent)
{
  _GLIBCXX_DEBUG_ASSERT(p_parent == p_nd->m_p_parent);
  _GLIBCXX_DEBUG_ASSERT(p_grandparent == p_parent->m_p_parent);

  _GLIBCXX_DEBUG_ONLY(base_type::assert_node_consistent(p_grandparent);)

  _GLIBCXX_DEBUG_ASSERT(p_parent->m_p_left == p_nd && 
		     p_nd->m_p_parent->m_p_parent->m_p_left == p_nd->m_p_parent);

  splay_zz_start(p_nd, p_parent, p_grandparent);

  node_pointer p_b = p_nd->m_p_right;
  node_pointer p_c = p_parent->m_p_right;

  p_nd->m_p_right = p_parent;
  p_parent->m_p_parent = p_nd;

  p_parent->m_p_right = p_grandparent;
  p_grandparent->m_p_parent = p_parent;

  p_parent->m_p_left = p_b;
  if (p_b != NULL)
    p_b->m_p_parent = p_parent;

  p_grandparent->m_p_left = p_c;
  if (p_c != NULL)
    p_c->m_p_parent = p_grandparent;

  splay_zz_end(p_nd, p_parent, p_grandparent);
}

PB_DS_CLASS_T_DEC
inline void
PB_DS_CLASS_C_DEC::
splay_zig_zig_right(node_pointer p_nd, node_pointer p_parent, 
		    node_pointer p_grandparent)
{
  _GLIBCXX_DEBUG_ASSERT(p_parent == p_nd->m_p_parent);
  _GLIBCXX_DEBUG_ASSERT(p_grandparent == p_parent->m_p_parent);
  _GLIBCXX_DEBUG_ONLY(base_type::assert_node_consistent(p_grandparent);)
  _GLIBCXX_DEBUG_ASSERT(p_parent->m_p_right == p_nd && 
	          p_nd->m_p_parent->m_p_parent->m_p_right == p_nd->m_p_parent);

  splay_zz_start(p_nd, p_parent, p_grandparent);

  node_pointer p_b = p_nd->m_p_left;
  node_pointer p_c = p_parent->m_p_left;

  p_nd->m_p_left = p_parent;
  p_parent->m_p_parent = p_nd;

  p_parent->m_p_left = p_grandparent;
  p_grandparent->m_p_parent = p_parent;

  p_parent->m_p_right = p_b;
  if (p_b != NULL)
    p_b->m_p_parent = p_parent;

  p_grandparent->m_p_right = p_c;
  if (p_c != NULL)
    p_c->m_p_parent = p_grandparent;

  base_type::update_to_top(p_grandparent, (node_update* )this);
  splay_zz_end(p_nd, p_parent, p_grandparent);
}

PB_DS_CLASS_T_DEC
inline void
PB_DS_CLASS_C_DEC::
splay_zz_start(node_pointer p_nd,
#ifdef _GLIBCXX_DEBUG
	       node_pointer p_parent,
#else 
	       node_pointer /*p_parent*/,
#endif
	       node_pointer p_grandparent)
{
  _GLIBCXX_DEBUG_ASSERT(p_nd != NULL);
  _GLIBCXX_DEBUG_ASSERT(p_parent != NULL);
  _GLIBCXX_DEBUG_ASSERT(p_grandparent != NULL);

  const bool grandparent_head = p_grandparent->m_p_parent == base_type::m_p_head;

  if (grandparent_head)
    {
      base_type::m_p_head->m_p_parent = base_type::m_p_head->m_p_parent;
      p_nd->m_p_parent = base_type::m_p_head;
      return;
    }

  node_pointer p_greatgrandparent = p_grandparent->m_p_parent;

  p_nd->m_p_parent = p_greatgrandparent;

  if (p_grandparent == p_greatgrandparent->m_p_left)
    p_greatgrandparent->m_p_left = p_nd;
  else
    p_greatgrandparent->m_p_right = p_nd;
}

PB_DS_CLASS_T_DEC
inline void
PB_DS_CLASS_C_DEC::
splay_zz_end(node_pointer p_nd, node_pointer p_parent, 
	     node_pointer p_grandparent)
{
  if (p_nd->m_p_parent == base_type::m_p_head)
    base_type::m_p_head->m_p_parent = p_nd;

  apply_update(p_grandparent, (node_update* )this);
  apply_update(p_parent, (node_update* )this);
  apply_update(p_nd, (node_update* )this);

  _GLIBCXX_DEBUG_ONLY(base_type::assert_node_consistent(p_nd);)
}