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/* Soot - a J*va Optimization Framework
 * Copyright (C) 1997 Clark Verbrugge
 *
 * 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 library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

/*
 * Modified by the Sable Research Group and others 1997-1999.  
 * See the 'credits' file distributed with Soot for the complete list of
 * contributors.  (Soot is distributed at http://www.sable.mcgill.ca/soot)
 */







package soot.coffi;

import java.util.Enumeration;

/** An enumeration of a Utf8 allows one to run through the characters in a
 * unicode string; used primarily for comparing unicode strings.  Note that
 * unlike regular enumerations, and to be efficient (ie to avoid allocating
 * an object in each call to nextElement), the return value is accessed by
 * this object's 'c' field, and nextElement merely returns this.
 * @see CONSTANT_Utf8_info
 * @see Utf8_Enumeration#c
 * @see Utf8_Enumeration#nextElement
 * @author Clark Verbrugge
 */
public class Utf8_Enumeration implements Enumeration {

   /** The latest character, as determined by nextElement.
    * @see Utf8_Enumeration#nextElement
    */
   public int c;            // latest character

   private short curindex;
   private short length;
   private byte bytes[];

   /** For creating an empty enumeration; you must use reset() after this
    * to initialize the enumeration.
    * @see Utf8_Enumeration#reset
    */
   public Utf8_Enumeration() {}
   /** For creating a normal enumeration of the given Utf8 string.
    * @param b array of bytes in Utf8 format.
    */
   public Utf8_Enumeration(byte b[]) {
      bytes = b;
      curindex = (short)2;
      length = (short)(((((bytes[0]))&0xff)<<8) + (((bytes[1]))&0xff) + 2);
   }
   /** Resets this object to be an enumeration of the given Utf8 string.
    * @param b array of bytes in Utf8 format.
    */
   public void reset(byte b[]) {
      bytes = b;
      curindex = (short)2;
      length = (short)(((((bytes[0]))&0xff)<<8) + (((bytes[1]))&0xff) + 2);
   }

   /** true if the entire string hasn't been enumerated yet. */
   public boolean hasMoreElements() {
      if (curindexthis
    * @see Utf8_Enumeration#c
    */
   public Object nextElement() {
      byte b;
      b = bytes[curindex++];
      if ((b&((byte)0x80))==0) { // one-byte character
         c = b;
      } else if ((b&((byte)0xe0))==0xc0) { // two-byte character
         c = ((b&((byte)0x1f)))<<6;
         b = bytes[curindex++];
         c |= (b&((byte)0x3f));
      } else {  // three-byte character
         c = ((b&((byte)0x0f)))<<12;
         b = bytes[curindex++];
         c |= ((b&((byte)0x3f)))<<6;
         b = bytes[curindex++];
         c |= (b&((byte)0x3f));
      }
      return this;
   }
}




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