retokenbackref.java

用java 编写的源码开放的文本编辑器。有很多有用的特性

/*
 *  gnu/regexp/RETokenBackRef.java
 *  Copyright (C) 1998-2001 Wes Biggs
 *
 *  This library is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as published
 *  by the Free Software Foundation; either version 2.1 of the License, 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 Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

package gnu.regexp;

final class RETokenBackRef extends REToken {
  private int num;
  private boolean insens;
  
  RETokenBackRef(int subIndex, int num, boolean insens) {
    super(subIndex);
    this.num = num;
    this.insens = insens;
  }

  // should implement getMinimumLength() -- any ideas?

    boolean match(CharIndexed input, REMatch mymatch) {
	int b,e;
	b = mymatch.start[num];
	e = mymatch.end[num];
	if ((b==-1)||(e==-1)) return false; // this shouldn't happen, but...
	for (int i=b; i<e; i++) {
	    if (input.charAt(mymatch.index+i-b) != input.charAt(i)) {
		return false;
	    }
	}
	mymatch.index += e-b;
	return next(input, mymatch);
    }
    
    void dump(StringBuffer os) {
	os.append('\\').append(num);
    }
}