/* pattern.java --
   Copyright (C) 2005 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath 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.

GNU Classpath 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.

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02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
module.  An independent module is a module which is not derived from
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this exception to your version of the library, but you are not
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exception statement from your version. */


package gnu.javax.swing.text.html.parser.support.low;


/**
 * The simple pattern, consisting from the sequence of tokens that
 * may have the unary modifier '?'. Choices and grouping
 * are not required here.
 * @author Audrius Meskauskas, Lithuania (AudriusA@Bioinformatics.org)
 */
public class pattern
{
  /**
   * The nodes of this pattern.
   */
  public final node[] nodes;

  /**
   * Create a pattern, containing the given list of nodes.
   * @param a_nodes
   */
  public pattern(node[] a_nodes)
  {
    nodes = a_nodes;
  }

  /**
   * Checks if the pattern can match the tokens in this
   * tokenizer. Does not change the state of tokenizer.
   * @param stream The tokenizer to read data from
   * @return True if the pattern sequence matches the
   * beginning of the tokenizer content.
   */
  public boolean matches(ReaderTokenizer stream)
  {
    try
      {
        int pt = 0;
        int pn = 0;
        Token t;
        node n;

        while (pn < nodes.length)
          {
            n = nodes [ pn ];
            t = stream.getTokenAhead(pt);

            if (t.kind == n.kind)
              {
                pn++;
                pt++;
              }
            else
              {
                if (!n.optional)
                  return false;
                else
                  pn++;
              }
          }
        return true;
      }
    catch (Exception ex)
      {
        throw new ParseException("Exception", ex);
      }
  }
}