;;; 
;;; Copyright (C) 2007 Lothar May l-may@gmx.de
;;; 
;;; All rights reserved.
;;; 
;;; Redistribution and use in source and binary forms, with or
;;; without modification, are permitted provided that the
;;; following conditions are met:
;;; 1. Redistributions of source code must retain the above
;;;    copyright notice, this list of conditions and the
;;;    following disclaimer.
;;; 2. Redistributions in binary form must reproduce the
;;;    above copyright notice, this list of conditions and
;;;    the following disclaimer in the documentation and/or
;;;    other materials provided with the distribution.
;;; 3. Neither the name of the project nor the names of
;;;    its contributors may be used to endorse or promote
;;;    products derived from this software without specific
;;;    prior written permission.
;;;  
;;; THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS
;;; ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
;;; BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
;;; MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
;;; DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS
;;; BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
;;; EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
;;; LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
;;; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
;;; HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
;;; IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
;;; NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
;;; USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
;;; OF SUCH DAMAGE.

;;;
;;; Software timer
;;;

(define timer-create
  (lambda (timeout-msec)
    (cons timeout-msec 0)))

(define timer-gettimeout
  (lambda (timer)
    (car timer)))

(define timer-getcurtime
  (lambda ()
    (let ((time (gettimeofday)))
      (+ (* (car time) 1000) (quotient (cdr time) 1000)))))

(define timer-start
  (lambda (timer)
    (cons (timer-gettimeout timer) (timer-getcurtime))))

(define timer-expired?
  (lambda (timer)
    (>= (timer-getcurtime) (+ (car timer) (cdr timer)))))