Copyright (c) 1992, 1995, 1996 Xerox Corporation.  All rights reserved.
Portions of this code were written by Stephen White, aka ghond.
Use and copying of this software and preparation of derivative works based
upon this software are permitted.  Any distribution of this software or
derivative works must comply with all applicable United States export
control laws.  This software is made available AS IS, and Xerox Corporation
makes no warranty about the software, its performance or its conformity to
any specification.  Any person obtaining a copy of this software is requested
to send their name and post office or electronic mail address to:
  Pavel Curtis
  Xerox PARC
  3333 Coyote Hill Rd.
  Palo Alto, CA 94304
  Pavel@Xerox.Com