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+/*
+ * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation. Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+
+/*
+ * The Original Code is HAT. The Initial Developer of the
+ * Original Code is Bill Foote, with contributions from others
+ * at JavaSoft/Sun.
+ */
+
+package jdk.test.lib.hprof.util;
+import java.util.*;
+
+/**
+ * A singleton utility class that sorts an array of objects.
+ * <p>
+ * Use:
+ * <pre>
+ *
+ * Stuff[] arr = ...;
+ * ArraySorter.sort(arr, new Comparer() {
+ * public int compare(Object lhs, Object rhs) {
+ * return ((String) lhs).compareTo((String) rhs);
+ * }
+ * });
+ * </pre>
+ *
+ * @author Bill Foote
+ */
+
+public class ArraySorter {
+
+ /**
+ * Sort the given array, using c for comparison
+ **/
+ static public void sort(Object[] arr, Comparer c) {
+ quickSort(arr, c, 0, arr.length-1);
+ }
+
+
+ /**
+ * Sort an array of strings, using String.compareTo()
+ **/
+ static public void sortArrayOfStrings(Object[] arr) {
+ sort(arr, new Comparer() {
+ public int compare(Object lhs, Object rhs) {
+ return ((String) lhs).compareTo((String) rhs);
+ }
+ });
+ }
+
+
+ static private void swap(Object[] arr, int a, int b) {
+ Object tmp = arr[a];
+ arr[a] = arr[b];
+ arr[b] = tmp;
+ }
+
+ //
+ // Sorts arr between from and to, inclusive. This is a quick, off-the-top-
+ // of-my-head quicksort: I haven't put any thought into optimizing it.
+ // I _did_ put thought into making sure it's safe (it will always
+ // terminate). Worst-case it's O(n^2), but it will usually run in
+ // in O(n log n). It's well-behaved if the list is already sorted,
+ // or nearly so.
+ //
+ static private void quickSort(Object[] arr, Comparer c, int from, int to) {
+ if (to <= from)
+ return;
+ int mid = (from + to) / 2;
+ if (mid != from)
+ swap(arr, mid, from);
+ Object pivot = arr[from]; // Simple-minded, but reasonable
+ int highestBelowPivot = from - 1;
+ int low = from+1;
+ int high = to;
+ // We now move low and high toward each other, maintaining the
+ // invariants:
+ // arr[i] <= pivot for all i < low
+ // arr[i] > pivot for all i > high
+ // As long as these invariants hold, and every iteration makes
+ // progress, we are safe.
+ while (low <= high) {
+ int cmp = c.compare(arr[low], pivot);
+ if (cmp <= 0) { // arr[low] <= pivot
+ if (cmp < 0) {
+ highestBelowPivot = low;
+ }
+ low++;
+ } else {
+ int c2;
+ for (;;) {
+ // arr[high] > pivot:
+ c2 = c.compare(arr[high], pivot);
+ if (c2 > 0) {
+ high--;
+ if (low > high) {
+ break;
+ }
+ } else {
+ break;
+ }
+ }
+ // At this point, low is never == high, BTW
+ if (low <= high) {
+ swap(arr, low, high);
+ if (c2 < 0) {
+ highestBelowPivot = low;
+ }
+ low++;
+ high--;
+ }
+ }
+ }
+ // At this point, low == high+1
+ // Now we just need to sort from from..highestBelowPivot
+ // and from high+1..to
+ if (highestBelowPivot > from) {
+ // pivot == pivot, so ensure algorithm terminates
+ swap(arr, from, highestBelowPivot);
+ quickSort(arr, c, from, highestBelowPivot-1);
+ }
+ quickSort(arr, c, high+1, to);
+ }
+}