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Utilities for use within Java projects

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/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed 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 dorkbox.util.collections;

import java.util.Comparator;

/** Provides methods to sort arrays of objects. Sorting requires working memory and this class allows that memory to be reused to
 * avoid allocation. The sorting is otherwise identical to the Arrays.sort methods (uses timsort).

 * 

 * Note that sorting primitive arrays with the Arrays.sort methods does not allocate memory (unless sorting large arrays of char,
 * short, or byte).
 * @author Nathan Sweet */
public class Sort {
	static private Sort instance;

	private TimSort timSort;
	private ComparableTimSort comparableTimSort;

	public  void sort (Array a) {
		if (comparableTimSort == null) comparableTimSort = new ComparableTimSort();
		comparableTimSort.doSort((Object[])a.items, 0, a.size);
	}

	public  void sort (T[] a) {
		if (comparableTimSort == null) comparableTimSort = new ComparableTimSort();
		comparableTimSort.doSort(a, 0, a.length);
	}

	public  void sort (T[] a, int fromIndex, int toIndex) {
		if (comparableTimSort == null) comparableTimSort = new ComparableTimSort();
		comparableTimSort.doSort(a, fromIndex, toIndex);
	}

	public  void sort (Array a, Comparator c) {
		if (timSort == null) timSort = new TimSort();
		timSort.doSort((Object[])a.items, (Comparator)c, 0, a.size);
	}

	public  void sort (T[] a, Comparator c) {
		if (timSort == null) timSort = new TimSort();
		timSort.doSort(a, c, 0, a.length);
	}

	public  void sort (T[] a, Comparator c, int fromIndex, int toIndex) {
		if (timSort == null) timSort = new TimSort();
		timSort.doSort(a, c, fromIndex, toIndex);
	}

	/** Returns a Sort instance for convenience. Multiple threads must not use this instance at the same time. */
	static public Sort instance () {
		if (instance == null) instance = new Sort();
		return instance;
	}
}