/*
 * 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.hadoop.hbase.util;

import java.util.ArrayList;
import java.util.Arrays;

import org.apache.hadoop.classification.InterfaceAudience;

/**
 * A set of array utility functions that return reasonable values in cases where an array is
 * allocated or if it is null
 */
@InterfaceAudience.Private
public class ArrayUtils {

  public static int length(byte[] a) {
    if (a == null) {
      return 0;
    }
    return a.length;
  }

  public static int length(long[] a) {
    if (a == null) {
      return 0;
    }
    return a.length;
  }

  public static int length(Object[] a) {
    if (a == null) {
      return 0;
    }
    return a.length;
  }

  public static boolean isEmpty(byte[] a) {
    if (a == null) {
      return true;
    }
    if (a.length == 0) {
      return true;
    }
    return false;
  }

  public static boolean isEmpty(long[] a) {
    if (a == null) {
      return true;
    }
    if (a.length == 0) {
      return true;
    }
    return false;
  }

  public static boolean isEmpty(Object[] a) {
    if (a == null) {
      return true;
    }
    if (a.length == 0) {
      return true;
    }
    return false;
  }

  public static long getFirst(long[] a) {
    return a[0];
  }

  public static long getLast(long[] a) {
    return a[a.length - 1];
  }

  public static int getTotalLengthOfArrays(Iterable<byte[]> arrays) {
    if (arrays == null) {
      return 0;
    }
    int length = 0;
    for (byte[] bytes : arrays) {
      length += length(bytes);
    }
    return length;
  }

  public static ArrayList<Long> toList(long[] array){
    int length = length(array);
    ArrayList<Long> list = new ArrayList<Long>(length);
    for(int i=0; i < length; ++i){
      list.add(array[i]);
    }
    return list;
  }

  public static byte[] growIfNecessary(byte[] array, int minLength, int numAdditionalBytes) {
    if(array.length >= minLength){
      return array;
    }
    return Arrays.copyOf(array, minLength + numAdditionalBytes);
  }

  public static int[] growIfNecessary(int[] array, int minLength, int numAdditionalInts) {
    if(array.length >= minLength){
      return array;
    }
    return Arrays.copyOf(array, minLength + numAdditionalInts);
  }

  public static long[] growIfNecessary(long[] array, int minLength, int numAdditionalLongs) {
    if(array.length >= minLength){
      return array;
    }
    return Arrays.copyOf(array, minLength + numAdditionalLongs);
  }

}
