CharsCharSequence.java

/*
 * Copyright 2014 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.util;

import java.util.Arrays;

public class CharsCharSequence implements CharSequence{
	public CharsCharSequence(char[] chars) {
		this(chars, 0, chars.length);
	}

	public CharsCharSequence(char[] chars, int start, int end) {
		if(chars.length < end) throw new ArrayIndexOutOfBoundsException(end);
		this.chars = chars;
		this.start = start;
		this.end = end;
	}

	@Override
	public int length() {
		return end - start;
	}

	@Override
	public char charAt(int index) {
		int i = start + index;
		if(i >= end) throw new ArrayIndexOutOfBoundsException(i);
		return chars[i];
	}

	@Override
	public CharSequence subSequence(int start, int end) {
		return new CharsCharSequence(chars, this.start + start, this.start + end);
	}

	public char[] toCharArray() {
		return Arrays.copyOfRange(chars, start, end);
	}

	public char[] subChars(int start, int end){
		int e = this.start + end;
		if(e >= end){
			throw new ArrayIndexOutOfBoundsException(e);
		}
		return Arrays.copyOfRange(chars, this.start + start, this.start + end);
	}

	private char[] chars;
	private int start;
	private int end;
}