package gnu.crypto.assembly;

// ----------------------------------------------------------------------------
// $Id: Direction.java,v 1.3 2005/10/06 04:24:13 rsdio Exp $
//
// Copyright (C) 2003, Free Software Foundation, Inc.
//
// This file is part of GNU Crypto.
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// it under the terms of the GNU General Public License as published by
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// General Public License for more details.
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// ----------------------------------------------------------------------------

/**
 * <p>An enumeration type for wiring {@link Stage} instances into {@link
 * Cascade} Cipher chains, as well as for operating a {@link Cascade} in a
 * given direction.</p>
 *
 * <p>The possible values for this type are two:</p>
 * <ol>
 *    <li>FORWARD: equivalent to {@link gnu.crypto.mode.IMode#ENCRYPTION}, and
 *    its inverse value</li>
 *    <li>REVERSED: equivalent to {@link gnu.crypto.mode.IMode#DECRYPTION}.</li>
 * </ol>
 *
 * @version $Revision: 1.3 $
 */
public final class Direction {

   // Constants and variables
   // -------------------------------------------------------------------------

   public static final Direction FORWARD = new Direction(1);
   public static final Direction REVERSED = new Direction(2);

   private int value;

   // Constructor(s)
   // -------------------------------------------------------------------------

   private Direction(int value) {
      super();

      this.value = value;
   }

   // Class methods
   // -------------------------------------------------------------------------

  public static final Direction reverse(Direction d) {
    return (d.equals(FORWARD) ? REVERSED : FORWARD);
  }

   // Instance methods
   // -------------------------------------------------------------------------

   public String toString() {
      return (this == FORWARD ? "forward" : "reversed");
   }
}