retokenoneof.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/RETokenOneOf.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;
import java.util.Vector;

final class RETokenOneOf extends REToken {
  private Vector options;
  private boolean negative;

  // This constructor is used for convenience when we know the set beforehand,
  // e.g. \d --> new RETokenOneOf("0123456789",false, ..)
  //      \D --> new RETokenOneOf("0123456789",true, ..)

  RETokenOneOf(int subIndex, String optionsStr, boolean negative, boolean insens) {
    super(subIndex);
    options = new Vector();
    this.negative = negative;
    for (int i = 0; i < optionsStr.length(); i++)
      options.addElement(new RETokenChar(subIndex,optionsStr.charAt(i),insens));
  }

  RETokenOneOf(int subIndex, Vector options, boolean negative) {
    super(subIndex);
    this.options = options;
    this.negative = negative;
  }

  int getMinimumLength() {
    int min = Integer.MAX_VALUE;
    int x;
    for (int i=0; i < options.size(); i++) {
      if ((x = ((REToken) options.elementAt(i)).getMinimumLength()) < min)
	min = x;
    }
    return min;
  }

    boolean match(CharIndexed input, REMatch mymatch) {
    if (negative && (input.charAt(mymatch.index) == CharIndexed.OUT_OF_BOUNDS)) 
      return false;

    REMatch newMatch = null;
    REMatch last = null;
    REToken tk;
    boolean isMatch;
    for (int i=0; i < options.size(); i++) {
	tk = (REToken) options.elementAt(i);
	REMatch tryMatch = (REMatch) mymatch.clone();
	if (tk.match(input, tryMatch)) { // match was successful
	    if (negative) return false;

	    if (next(input, tryMatch)) {
		// Add tryMatch to list of possibilities.
		if (last == null) {
		    newMatch = tryMatch;
		    last = tryMatch;
		} else {
		    last.next = tryMatch;
		    last = tryMatch;
		}
	    } // next succeeds
	} // is a match
    } // try next option

    if (newMatch != null) {
	if (negative) {
	    return false;
	} else {
	    // set contents of mymatch equal to newMatch

	    // try each one that matched
	    mymatch.assignFrom(newMatch);
	    return true;
	}
    } else {
	if (negative) {
	    ++mymatch.index;
	    return next(input, mymatch);
	} else {
	    return false;
	}
    }

    // index+1 works for [^abc] lists, not for generic lookahead (--> index)
  }

  void dump(StringBuffer os) {
    os.append(negative ? "[^" : "(?:");
    for (int i = 0; i < options.size(); i++) {
      if (!negative && (i > 0)) os.append('|');
      ((REToken) options.elementAt(i)).dumpAll(os);
    }
    os.append(negative ? ']' : ')');
  }  
}