blob: af6c4f8b76e72f58bfd81a91dc557b58885dc65d [file] [log] [blame]
/*
* 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.datasketches.common;
import java.util.Random;
/**
* @author Lee Rhodes
*/
public final class Shuffle {
private static final Random rand = new Random();
/**
* Shuffle the given input array using a default source of randomness.
* @param array the array to be shuffled.
*/
public static void shuffle(final float[] array) {
shuffle(array, rand);
}
/**
* Shuffle the given input array using the given source of randomness.
* @param array the array to be shuffled.
* @param rand the source of randomness used to shuffle the list.
*/
public static void shuffle(final float[] array, final Random rand) {
final int arrLen = array.length;
for (int i = 0; i < arrLen; i++) {
final int r = rand.nextInt(i + 1);
swap(array, i, r);
}
}
private static void swap(final float[] array, final int i1, final int i2) {
final float value = array[i1];
array[i1] = array[i2];
array[i2] = value;
}
/**
* Shuffle the given input array using a default source of randomness.
* @param array the array to be shuffled.
*/
public static void shuffle(final double[] array) {
shuffle(array, rand);
}
/**
* Shuffle the given input array using the given source of randomness.
* @param array the array to be shuffled.
* @param rand the source of randomness used to shuffle the list.
*/
public static void shuffle(final double[] array, final Random rand) {
final int arrLen = array.length;
for (int i = 0; i < arrLen; i++) {
final int r = rand.nextInt(i + 1);
swap(array, i, r);
}
}
private static void swap(final double[] array, final int i1, final int i2) {
final double value = array[i1];
array[i1] = array[i2];
array[i2] = value;
}
/**
* Shuffle the given input array using a default source of randomness.
* @param array the array to be shuffled.
*/
public static void shuffle(final long[] array) {
shuffle(array, rand);
}
/**
* Shuffle the given input array using the given source of randomness.
* @param array the array to be shuffled.
* @param rand the source of randomness used to shuffle the list.
*/
public static void shuffle(final long[] array, final Random rand) {
final int arrLen = array.length;
for (int i = 0; i < arrLen; i++) {
final int r = rand.nextInt(i + 1);
swap(array, i, r);
}
}
private static void swap(final long[] array, final int i1, final int i2) {
final long value = array[i1];
array[i1] = array[i2];
array[i2] = value;
}
/**
* Shuffle the given input array using a default source of randomness.
* @param array the array to be shuffled.
*/
public static void shuffle(final int[] array) {
shuffle(array, rand);
}
/**
* Shuffle the given input array using the given source of randomness.
* @param array the array to be shuffled.
* @param rand the source of randomness used to shuffle the list.
*/
public static void shuffle(final int[] array, final Random rand) {
final int arrLen = array.length;
for (int i = 0; i < arrLen; i++) {
final int r = rand.nextInt(i + 1);
swap(array, i, r);
}
}
private static void swap(final int[] array, final int i1, final int i2) {
final int value = array[i1];
array[i1] = array[i2];
array[i2] = value;
}
/**
* Shuffle the given input array using a default source of randomness.
* @param array the array to be shuffled.
* @param <T> the component type of the given array.
*/
public static <T> void shuffle(final T[] array) {
shuffle(array, rand);
}
/**
* Shuffle the given input array using the given source of randomness.
* @param array the array to be shuffled.
* @param rand the source of randomness used to shuffle the list.
* @param <T> the component type of the given array.
*/
public static <T> void shuffle(final T[] array, final Random rand) {
final int arrLen = array.length;
for (int i = 0; i < arrLen; i++) {
final int r = rand.nextInt(i + 1);
swap(array, i, r);
}
}
private static<T> void swap(final T[] array, final int i1, final int i2) {
final T value = array[i1];
array[i1] = array[i2];
array[i2] = value;
}
}