/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.flink.runtime.util;

import java.util.Arrays;
import java.util.NoSuchElementException;

/**
 * Minimal implementation of an array-backed list of ints
 */
public class IntArrayList {
	
	private int size;
	
	private int[] array;

	public IntArrayList(final int capacity) {
		this.size = 0;
		this.array = new int[capacity];
	}
	
	public int size() {
		return size;
	}
	
	public boolean add(final int number) {
		grow(size+1);
		array[size++] = number;
		return true;
	}

	public int removeLast() {
		if (size == 0) {
			throw new NoSuchElementException();
		}
		--size;
		return array[size];
	}
	
	public void clear() {
		size = 0;
	}
	
	public boolean isEmpty() {
		return size == 0;
	}
	
	private void grow(final int length) {
		if(length > array.length) {
			final int newLength = (int)Math.max(Math.min(2L * array.length, Integer.MAX_VALUE-8), length);
			final int[] t = new int[newLength];
			System.arraycopy(array, 0, t, 0, size);
			array = t;
		}
	}

	public int[] toArray() {
		return Arrays.copyOf(array, size);
	}

	public static final IntArrayList EMPTY = new IntArrayList(0) {
		
		@Override
		public boolean add(int number) {
			throw new UnsupportedOperationException();
		}

		@Override
		public int removeLast() {
			throw new UnsupportedOperationException();
		};
	};
}