/*
* Copyright (c) 1997, 2008, 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
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*/
/*
* The Original Code is HAT. The Initial Developer of the
* Original Code is Bill Foote, with contributions from others
* at JavaSoft/Sun.
*/
package com.sun.tools.hat.internal.util;
import java.util.*;
/**
* A singleton utility class that sorts a vector.
* <p>
* Use:
* <pre>
*
* Vector v = <a vector of, say, String objects>;
* VectorSorter.sort(v, new Comparer() {
* public int compare(Object lhs, Object rhs) {
* return ((String) lhs).compareTo((String) rhs);
* }
* });
* </pre>
*
* @author Bill Foote
*/
public class VectorSorter {
/**
* Sort the given vector, using c for comparison
**/
static public void sort(Vector<Object> v, Comparer c) {
quickSort(v, c, 0, v.size()-1);
}
/**
* Sort a vector of strings, using String.compareTo()
**/
static public void sortVectorOfStrings(Vector<Object> v) {
sort(v, new Comparer() {
public int compare(Object lhs, Object rhs) {
return ((String) lhs).compareTo((String) rhs);
}
});
}
static private void swap(Vector<Object> v, int a, int b) {
Object tmp = v.elementAt(a);
v.setElementAt(v.elementAt(b), a);
v.setElementAt(tmp, b);
}
//
// Sorts v 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(Vector<Object> v, Comparer c, int from, int to) {
if (to <= from)
return;
int mid = (from + to) / 2;
if (mid != from)
swap(v, mid, from);
Object pivot = v.elementAt(from);
// Simple-minded, but reasonable
int highestBelowPivot = from - 1;
int low = from+1;
int high = to;
// We now move low and high toward eachother, maintaining the
// invariants:
// v[i] <= pivot for all i < low
// v[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(v.elementAt(low), pivot);
if (cmp <= 0) { // v[low] <= pivot
if (cmp < 0) {
highestBelowPivot = low;
}
low++;
} else {
int c2;
for (;;) {
c2 = c.compare(v.elementAt(high), pivot);
// v[high] > pivot:
if (c2 > 0) {
high--;
if (low > high) {
break;
}
} else {
break;
}
}
// At this point, low is never == high
if (low <= high) {
swap(v, low, high);
if (c2 < 0) {
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