rbNode.H

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/*
                          Aleph_w
 
  Data structures & Algorithms
  version 2.0.0b
  https://github.com/lrleon/Aleph-w
 
  This file is part of Aleph-w library
 
  Copyright (c) 2002-2026 Leandro Rabindranath Leon
 
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:
 
  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.
 
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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  SOFTWARE.
*/
 
 
# ifndef TPL_RBNODE_H
# define TPL_RBNODE_H
 
# include <tpl_binNode.H>
 
typedef unsigned char Color;
 
# define COLOR(p) ((p)->getColor())
 
# define RED      (0)
 
# define BLACK    (1)
 
class RbNode_Data
{
private:  
 
  Color  color;  
 
public:
 
  RbNode_Data() : color(RED) {}
 
  RbNode_Data(SentinelCtor) : color(BLACK) {}
 
  Color & getColor() { return color; }
 
  void reset() { color = RED; }
 
}; 
 
DECLARE_BINNODE_SENTINEL(RbNode, 128, RbNode_Data);
 
    template <class Node>
bool test_black_condition(Node *p, int &max, int bh = 0)
{
  if (p == Node::NullPtr)
    return true;
 
  if (COLOR(p) == BLACK)
    bh++; // count this black node
 
  if (LLINK(p) == Node::NullPtr and RLINK(p) == Node::NullPtr)
    {
      if (max == -1) // first leaf reached
        max = bh;
      
      return bh == max;
    }
    
  return test_black_condition(LLINK(p), max, bh) and 
         test_black_condition(RLINK(p), max, bh);
}
 
    template <class Node>
bool is_red_black(Node * node)
{
  if (node == Node::NullPtr)
    return true;
 
  if (not (COLOR(node) == RED or COLOR(node) == BLACK))
    return false;
 
  // Red nodes cannot have red children
  if (COLOR(node) == RED)
    if (COLOR(LLINK(node)) == RED or COLOR(RLINK(node)) == RED)
      return false; 
 
  int max = -1;
 
  return test_black_condition(node, max, 0);
}
 
    template <class Node>
bool is_red_black_tree(Node * node)
{
  if (not is_red_black(node))
    return false;
 
  if (not is_red_black(LLINK(node)) or not is_red_black(RLINK(node)))
    return false;
 
  return true;
}
 
    template <class Node, class Compare>
bool is_red_black_bst(Node * node, Compare & cmp)
{
  if (not is_red_black_tree(node))
    return false;
 
  return check_bst(node, cmp);
}
# endif // TPL_RBNODE_H