;;;; -*- Mode: Lisp; Syntax: ANSI-Common-Lisp; Base: 10 -*-
;;;; *************************************************************************
;;;; FILE IDENTIFICATION
;;;;
;;;; Name:          random.lisp
;;;; Purpose:       Random number functions for GENUTILS package
;;;; Programmer:    Kevin M. Rosenberg
;;;; Date Started:  Apr 2000
;;;;
;;;; $Id: random.lisp,v 1.1 2002/10/06 13:21:47 kevin Exp $
;;;;
;;;; This file, part of Genutils, is Copyright (c) 2002 by Kevin M. Rosenberg
;;;;
;;;; Genutils users are granted the rights to distribute and use this software
;;;; as governed by the terms of the GNU General Public License.
;;;; *************************************************************************

(in-package :genutils)

(defun seed-random-generator ()
  "Evaluate a random number of items"
  (let ((randfile (make-pathname 
		   :directory '(:absolute "dev") 
		   :name "urandom")))
    (setf *random-state* (make-random-state t))
    (if (probe-file randfile)
	(with-open-file
	    (rfs randfile :element-type 'unsigned-byte)
	  (let* 
	      ;; ((seed (char-code (read-char rfs))))
	      ((seed (read-byte rfs)))
	    ;;(format t "Randomizing!~%")
	    (loop
		for item from 1 to seed
		do (loop
		       for it from 0 to (+ (read-byte rfs) 5)
		       do (random 65536))))))))


(defmacro random-choice (&rest exprs)
  `(case (random ,(length exprs))
     ,@(let ((key -1))
         (mapcar #'(lambda (expr)
                     `(,(incf key) ,expr))
                 exprs))))