Added splice() variant for int[][].

git-svn-id: https://samskivert.googlecode.com/svn/trunk@836 6335cc39-0255-0410-8fd6-9bcaacd3b74c

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

@@ -1,5 +1,5 @@
 //
-// $Id: ArrayUtil.java,v 1.16 2002/09/06 02:36:12 shaper Exp $
+// $Id: ArrayUtil.java,v 1.17 2002/09/19 23:37:40 shaper Exp $
 //
 // samskivert library - useful routines for java programs
 // Copyright (C) 2001 Walter Korman
@@ -525,6 +525,59 @@ public class ArrayUtil
         return nvalues;
     }
 
+    /**
+     * Creates and returns a new array sized to fit and populated with the
+     * subset of values from indexes <code>0</code> to </code>offset -
+     * 1</code> (inclusive) in the supplied array.
+     *
+     * @param values the array of values to splice.
+     * @param offset the index within the <code>values</code> array after
+     * which all subsequent values are to be removed.  This must be a
+     * valid index within the <code>values</code> array.
+     */
+    public static int[][] splice (int[][] values, int offset)
+    {
+        int length = (values == null) ? 0 : values.length - offset;
+        return splice(values, offset, length);
+    }
+
+    /**
+     * Creates and returns a new array sized to fit and populated with the
+     * concatenated subset of values from indexes <code>0</code> to
+     * </code>offset - 1</code>, and <code>offset + length</code> to
+     * <code>values.length</code> (inclusive) in the supplied array.
+     *
+     * @param values the array of values to splice.
+     * @param offset the index within the <code>values</code> array at
+     * which the first element will be removed.  This must be a valid
+     * index within the <code>values</code> array.
+     * @param length the number of elements to be removed.  Note that
+     * <code>offset + length</code> must be a valid index within the
+     * <code>values</code> array.
+     */
+    public static int[][] splice (int[][] values, int offset, int length)
+    {
+        // make sure we've something to work with
+        if (values == null) {
+            throw new IllegalArgumentException("Can't splice a null array.");
+        }
+
+        // require that the entire range to remove be within the array bounds
+        int size = values.length;
+        int tstart = offset + length;
+        if (offset < 0 || tstart > size) {
+            throw new ArrayIndexOutOfBoundsException(
+                "Splice range out of bounds [offset=" + offset +
+                ", length=" + length + ", size=" + size + "].");
+        }
+
+        // create a new array and populate it with the spliced-in values
+        int[][] nvalues = new int[size - length][];
+        System.arraycopy(values, 0, nvalues, 0, offset);
+        System.arraycopy(values, tstart, nvalues, offset, size - tstart);
+        return nvalues;
+    }
+
     /** The random object used when shuffling an array. */
     protected static Random _rnd = new Random();
 }