/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * JFlex 1.4.3                                                             *
 * Copyright (C) 1998-2009  Gerwin Klein <lsf@jflex.de>                    *
 * All rights reserved.                                                    *
 *                                                                         *
 * This program is free software; you can redistribute it and/or modify    *
 * it under the terms of the GNU General Public License. See the file      *
 * COPYRIGHT for more information.                                         *
 *                                                                         *
 * This program 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 program; if not, write to the Free Software Foundation, Inc., *
 * 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA                 *
 *                                                                         *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

package JFlex;

/**
 * A list of pairs of states. Used in DFA minimization.
 *
 * @author Gerwin Klein
 * @version JFlex 1.4.3, $Revision: 433 $, $Date: 2009-01-31 19:52:34 +1100 (Sat, 31 Jan 2009) $
 */
final public class StatePairList {

  // implemented as two arrays of integers.
  // java.util classes proved too inefficient.

  int p [];
  int q [];
  
  int num;

  public StatePairList() {
    p = new int [8];
    q = new int [8];
    num = 0;
  }

  public void addPair(int i, int j) {
    for (int x = 0; x < num; x++)
      if (p[x] == i && q[x] == j) return;

    if (num >= p.length) increaseSize(num);

    p[num] = i;
    q[num] = j;
    
    num++;
  }

  public void markAll(StatePairList [] [] list, boolean [] [] equiv) {
    for (int x = 0; x < num; x++) {
      int i = p[x];
      int j = q[x];
      
      if (equiv[i][j]) {
        equiv[i][j] = false;
        if (list[i][j] != null) 
          list[i][j].markAll(list, equiv);
      }
    }
  }

  private void increaseSize(int length) {
    length = Math.max(length+1, 4*p.length);
    Out.debug("increasing length to "+length); //$NON-NLS-1$
                               
    int pn [] = new int[length];
    int qn [] = new int[length];

    System.arraycopy(p, 0, pn, 0, p.length);
    System.arraycopy(q, 0, qn, 0, q.length);

    p = pn; 
    q = qn;
  } 
}
