Added byte[] and long[] variants of shuffle().

git-svn-id: https://samskivert.googlecode.com/svn/trunk@762 6335cc39-0255-0410-8fd6-9bcaacd3b74c

projects/samskivert/src/java/com/samskivert/util/ArrayUtil.java

@@ -1,5 +1,5 @@
 //
-// $Id: ArrayUtil.java,v 1.2 2001/12/14 19:07:47 shaper Exp $
+// $Id: ArrayUtil.java,v 1.3 2002/05/28 22:32:14 shaper Exp $
 //
 // samskivert library - useful routines for java programs
 // Copyright (C) 2001 Walter Korman
@@ -27,6 +27,34 @@ import java.util.Random;
  */
 public class ArrayUtil
 {
+    /**
+     * Shuffles the elements in the given array into a random sequence.
+     *
+     * @param values the array to shuffle.
+     */
+    public static void shuffle (byte[] values)
+    {
+        shuffle(values, 0, values.length);
+    }
+
+    /**
+     * Shuffles a subset of elements within the specified array into a
+     * random sequence.
+     *
+     * @param values the array containing elements to shuffle.
+     * @param offset the index at which to start shuffling elements.
+     * @param length the number of elements to shuffle.
+     */
+    public static void shuffle (byte[] values, int offset, int length)
+    {
+        for (int ii = (offset + length); ii > (offset + 1); ii--) {
+            byte temp = values[ii - 1];
+            int idx = _rnd.nextInt(ii);
+            values[ii - 1] = values[idx];
+            values[idx] = temp;
+        }
+    }
+
     /**
      * Shuffles the elements in the given array into a random sequence.
      *
@@ -38,7 +66,8 @@ public class ArrayUtil
     }
 
     /**
-     * Shuffles a subset of elements within the specified array.
+     * Shuffles a subset of elements within the specified array into a
+     * random sequence.
      *
      * @param values the array containing elements to shuffle.
      * @param offset the index at which to start shuffling elements.
@@ -54,6 +83,34 @@ public class ArrayUtil
         }
     }
 
+    /**
+     * Shuffles the elements in the given array into a random sequence.
+     *
+     * @param values the array to shuffle.
+     */
+    public static void shuffle (long[] values)
+    {
+        shuffle(values, 0, values.length);
+    }
+
+    /**
+     * Shuffles a subset of elements within the specified array into a
+     * random sequence.
+     *
+     * @param values the array containing elements to shuffle.
+     * @param offset the index at which to start shuffling elements.
+     * @param length the number of elements to shuffle.
+     */
+    public static void shuffle (long[] values, int offset, int length)
+    {
+        for (int ii = (offset + length); ii > (offset + 1); ii--) {
+            long temp = values[ii - 1];
+            int idx = _rnd.nextInt(ii);
+            values[ii - 1] = values[idx];
+            values[idx] = temp;
+        }
+    }
+
     /** The random object used when shuffling an array. */
     protected static Random _rnd = new Random();
 }