| /* |
| * 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; |
| } |
| |
| } |