ArrayChunk.java

/**
 *   Copyright (c) Rich Hickey. All rights reserved.
 *   The use and distribution terms for this software are covered by the
 *   Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
 *   which can be found in the file epl-v10.html at the root of this distribution.
 *   By using this software in any fashion, you are agreeing to be bound by
 * 	 the terms of this license.
 *   You must not remove this notice, or any other, from this software.
 **/

/* rich May 24, 2009 */

package com.trifork.clj_ds;

import java.io.Serializable;

public final class ArrayChunk<T> implements IChunk<T>, Serializable {

final Object[] array;
final int off;
final int end;

public ArrayChunk(Object[] array){
	this(array, 0, array.length);
}

public ArrayChunk(Object[] array, int off){
	this(array, off, array.length);
}

public ArrayChunk(Object[] array, int off, int end){
	this.array = array;
	this.off = off;
	this.end = end;
}

public T nth(int i){
	return (T) array[off + i];
}

public T nth(int i, T notFound){
	if(i >= 0 && i < count())
		return nth(i);
	return notFound;
}

public int count(){
	return end - off;
}

public IChunk<T> dropFirst(){
	if(off==end)
		throw new IllegalStateException("dropFirst of empty chunk");
	return new ArrayChunk<T>(array, off + 1, end);
}

public Object reduce(IFn f, Object start) throws Exception{
		Object ret = f.invoke(start, array[off]);
		for(int x = off + 1; x < end; x++)
			ret = f.invoke(ret, array[x]);
		return ret;
}
}