io-multiplex/time.lisp

   1 ;;;; -*- Mode: Lisp; Syntax: ANSI-Common-Lisp; Indent-tabs-mode: NIL -*-
   2 ;;;
   3 ;;; time.lisp --- Various time-related functions.
   4 ;;;
   5 ;;; Copyright (C) 2006-2007, Stelian Ionescu  <sionescu@common-lisp.net>
   6 ;;;
   7 ;;; This code is free software; you can redistribute it and/or
   8 ;;; modify it under the terms of the version 2.1 of
   9 ;;; the GNU Lesser General Public License as published by
  10 ;;; the Free Software Foundation, as clarified by the
  11 ;;; preamble found here:
  12 ;;;     http://opensource.franz.com/preamble.html
  13 ;;;
  14 ;;; This program is distributed in the hope that it will be useful,
  15 ;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 ;;; GNU General Public License for more details.
  18 ;;;
  19 ;;; You should have received a copy of the GNU Lesser General
  20 ;;; Public License along with this library; if not, write to the
  21 ;;; Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
  22 ;;; Boston, MA 02110-1301, USA
  23
  24 (in-package :io.multiplex)
  25
  26 ;;;; Timeouts
  27
  28 (deftype timeout ()
  29   'double-float)
  30
  31 ;;; Break a real timeout into seconds and microseconds.
  32 (defun decode-timeout (timeout)
  33   (typecase timeout
  34     (integer (values timeout 0))
  35     (null    nil)
  36     (real
  37      (multiple-value-bind (q r) (truncate (coerce timeout 'double-float))
  38        (declare (type unsigned-byte q)
  39                 (type double-float r))
  40        (values q (the (values unsigned-byte t) (truncate (* r 1d6))))))
  41     (t
  42      (error "Timeout is not a real number or NIL: ~S" timeout))))
  43
  44 (defun normalize-timeout (timeout)
  45   (assert (not (minusp timeout)) (timeout)
  46            "The timeout must be non-negative: ~A" timeout)
  47   (coerce timeout 'double-float))
  48
  49 (defun abs-timeout (timeout)
  50   (+ (osicat:get-monotonic-time) (normalize-timeout timeout)))
  51
  52 (defun min-timeout (&rest timeouts)
  53   (collect-min (choose-if #'identity (scan timeouts))))