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+/* Sequence.java -- a sequence of integers.
+   Copyright (C) 2004, 2006 Free Software Foundation, Inc.
+
+This file is a part of GNU Classpath.
+
+GNU Classpath 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; either version 2 of the License, or (at
+your option) any later version.
+
+GNU Classpath 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.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; if not, write to the Free Software
+Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
+USA
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version.  */
+
+
+package gnu.java.security.util;
+
+import java.util.AbstractList;
+import java.util.LinkedList;
+
+/**
+ * A monotonic sequence of integers in the finite field 2<sup>32</sup>.
+ */
+public final class Sequence extends AbstractList
+{
+
+  // Field.
+  // ------------------------------------------------------------------------
+
+  private final Integer[] sequence;
+
+  // Constructor.
+  // ------------------------------------------------------------------------
+
+  /**
+   * Create a sequence of integers from 0 to <i>end</i>, with an increment
+   * of 1. If <i>end</i> is less than 0, then the sequence will wrap around
+   * through all positive integers then negative integers until the end
+   * value is reached. Naturally, this will result in an enormous object,
+   * so don't do this.
+   *
+   * @param end The ending value.
+   */
+  public Sequence(int end)
+  {
+    this(0, end, 1);
+  }
+
+  /**
+   * Create a sequence of integers from <i>start</i> to <i>end</i>, with an
+   * increment of 1. If <i>end</i> is less than <i>start</i>, then the sequence
+   * will wrap around until the end value is reached. Naturally, this will
+   * result in an enormous object, so don't do this.
+   *
+   * @param start The starting value.
+   * @param end The ending value.
+   */
+  public Sequence(int start, int end)
+  {
+    this(start, end, 1);
+  }
+
+  /**
+   * Create a sequence of integers from <i>start</i> to <i>end</i>, with an
+   * increment of <i>span</i>. If <i>end</i> is less than <i>start</i>, then
+   * the sequence will wrap around until the end value is reached. Naturally,
+   * this will result in an enormous object, so don't do this.
+   *
+   * <p><i>span</i> can be negative, resulting in a decresing sequence.
+   *
+   * <p>If <i>span</i> is 0, then the sequence will contain {<i>start</i>,
+   * <i>end</i>} if <i>start</i> != <i>end</i>, or just the singleton
+   * <i>start</i> if <i>start</i> == <i>end</i>.
+   *
+   * @param start The starting value.
+   * @param end The ending value.
+   * @param span The increment value.
+   */
+  public Sequence(int start, int end, int span)
+  {
+    if (span == 0)
+      {
+        if (start != end)
+          {
+            sequence = new Integer[] { new Integer(start), new Integer(end) };
+          }
+        else
+          {
+            sequence = new Integer[] { new Integer(start) };
+          }
+      }
+    else
+      {
+        LinkedList l = new LinkedList();
+        for (int i = start; i != end; i += span)
+          {
+            l.add(new Integer(i));
+          }
+        l.add(new Integer(end));
+        sequence = (Integer[]) l.toArray(new Integer[l.size()]);
+      }
+  }
+
+  // Instance methods.
+  // ------------------------------------------------------------------------
+
+  public Object get(int index)
+  {
+    if (index < 0 || index >= size())
+      {
+        throw new IndexOutOfBoundsException("index=" + index + ", size="
+                                            + size());
+      }
+    return sequence[index];
+  }
+
+  public int size()
+  {
+    return sequence.length;
+  }
+
+  public Object[] toArray()
+  {
+    return (Object[]) sequence.clone();
+  }
+}