TailCharIterator.java

/*
 * Copyright 2012 Takao Nakaguchi
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.trie4j.tail;

import java.util.NoSuchElementException;

public class TailCharIterator{
	public TailCharIterator(CharSequence chars, int index){
		this.chars = chars;
		this.index = index;
		if(this.index != -1){
			this.next = chars.charAt(index);
		}
	}

	public void setOffset(int offset){
		setIndex(offset);
	}
	public void setIndex(int index){
		this.index = index;
		this.current = '\0';
		if(this.index != -1){
			this.next = this.chars.charAt(index);
		} else{
			this.next = '\0';
		}
	}

	public int getNextIndex(){
		return index;
	}

	public boolean hasNext() {
		return index != -1;
	}

	public char next() {
		if(!hasNext()){
			throw new NoSuchElementException();
		}
		current = next;
		index++;
		char c = chars.charAt(index);
		if(c == '\0'){
			index = -1;
		} else if(c == '\1'){
			int i = chars.charAt(index + 1);
			i += chars.charAt(index + 2) << 16;
			index = i;
			c = chars.charAt(index);
		}
		next = c;
		return current;
	}

	public char current(){
		return current;
	}

	private CharSequence chars;
	private int index;
	private char current = '\0';
	private char next = '\0';
}