--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/org/tmatesoft/hg/internal/ArrayHelper.java	Sat Sep 24 04:06:27 2011 +0200
@@ -0,0 +1,126 @@
+/*
+ * Copyright (c) 2011 TMate Software Ltd
+ *  
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program 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 for more details.
+ *
+ * For information on how to redistribute this software under
+ * the terms of a license other than GNU General Public License
+ * contact TMate Software at support@hg4j.com
+ */
+package org.tmatesoft.hg.internal;
+
+/**
+ * 
+ * @author Artem Tikhomirov
+ * @author TMate Software Ltd.
+ */
+public class ArrayHelper {
+	private int[] reverse;
+
+	@SuppressWarnings("unchecked")
+	public void sort(Comparable<?>[] a) {
+//		Object[] aux = (Object[]) a.clone();
+		reverse = new int[a.length];
+		sort1((Comparable<Object>[])a, 0, a.length);
+	}
+	
+    private void sort1(Comparable<Object> x[], int off, int len) {
+    	// Insertion sort on smallest arrays
+    	if (len < 7) {
+    	    for (int i=off; i<len+off; i++)
+    			for (int j=i; j>off && x[j-1].compareTo(x[j]) > 0; j--)
+    			    swap(x, j, j-1);
+    	    return;
+    	}
+
+    	// Choose a partition element, v
+    	int m = off + (len >> 1);       // Small arrays, middle element
+    	if (len > 7) {
+    	    int l = off;
+    	    int n = off + len - 1;
+    	    if (len > 40) {        // Big arrays, pseudomedian of 9
+    			int s = len/8;
+	    		l = med3(x, l,     l+s, l+2*s);
+	    		m = med3(x, m-s,   m,   m+s);
+	    		n = med3(x, n-2*s, n-s, n);
+    	    }
+    	    m = med3(x, l, m, n); // Mid-size, med of 3
+    	}
+    	Comparable<Object> v = x[m];
+
+    	// Establish Invariant: v* (<v)* (>v)* v*
+    	int a = off, b = a, c = off + len - 1, d = c;
+    	while(true) {
+    	    while (b <= c && x[b].compareTo(v) <= 0) {
+    			if (x[b] == v)
+    			    swap(x, a++, b);
+    			b++;
+    	    }
+    	    while (c >= b && x[c].compareTo(v) >= 0) {
+    			if (x[c] == v)
+    			    swap(x, c, d--);
+    			c--;
+    	    }
+    	    if (b > c)
+    			break;
+    	    swap(x, b++, c--);
+    	}
+
+    	// Swap partition elements back to middle
+    	int s, n = off + len;
+    	s = Math.min(a-off, b-a  );  vecswap(x, off, b-s, s);
+    	s = Math.min(d-c,   n-d-1);  vecswap(x, b,   n-s, s);
+
+    	// Recursively sort non-partition-elements
+    	if ((s = b-a) > 1)
+    	    sort1(x, off, s);
+    	if ((s = d-c) > 1)
+    	    sort1(x, n-s, s);
+    }
+
+    /**
+     * Swaps x[a .. (a+n-1)] with x[b .. (b+n-1)].
+     */
+    private void vecswap(Object[] x, int a, int b, int n) {
+		for (int i=0; i<n; i++, a++, b++) {
+		    swap(x, a, b);
+		}
+    }
+
+    /**
+     * Returns the index of the median of the three indexed integers.
+     */
+    private static int med3(Comparable<Object>[] x, int a, int b, int c) {
+	return (x[a].compareTo(x[b]) < 0 ?
+		(x[b].compareTo(x[c]) < 0 ? b : x[a].compareTo(x[c]) < 0 ? c : a) :
+		(x[b].compareTo(x[c]) > 0 ? b : x[a].compareTo(x[c]) > 0 ? c : a));
+    }
+
+
+	/**
+	 * @return the reverse
+	 */
+	public int[] getReverse() {
+		return reverse;
+	}
+
+	/**
+	 * Swaps x[a] with x[b].
+	 */
+	private void swap(Object[] x, int a, int b) {
+		Object t = x[a];
+		x[a] = x[b];
+		x[b] = t;
+		int z1 = reverse[a] != 0 ? reverse[a] : a+1;
+		int z2 = reverse[b] != 0 ? reverse[b] : b+1;
+		reverse[b] = z1;
+		reverse[a] = z2;
+	}
+}