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;; Simple time manipulation library.
;; Copyright (C) 2017 g10 Code GmbH
;;
;; This file is part of Libgpg-error.
;;
;; Libgpg-error is free software; you can redistribute it and/or
;; modify it under the terms of the GNU Lesser General Public License
;; as published by the Free Software Foundation; either version 2.1 of
;; the License, or (at your option) any later version.
;;
;; Libgpg-error is distributed in the hope that it will be useful, but
;; WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;; Lesser General Public License for more details.
;;
;; You should have received a copy of the GNU Lesser General Public
;; License along with this program; if not, see <https://www.gnu.org/licenses/>.

;; This library mimics what GnuPG thinks about expiration times.
;; Granularity is one second.  Its focus is not on correctness.

;; Conversion functions.
(define (minutes->seconds minutes)
  (* minutes 60))
(define (hours->seconds hours)
  (* hours 60 60))
(define (days->seconds days)
  (* days 24 60 60))
(define (weeks->seconds weeks)
  (days->seconds (* weeks 7)))
(define (months->seconds months)
  (days->seconds (* months 30)))
(define (years->seconds years)
  (days->seconds (* years 365)))

(define (time-matches? a b slack)
  (< (abs (- a b)) slack))
(assert (time-matches? (hours->seconds 1) (hours->seconds 2) (hours->seconds 2)))
(assert (time-matches? (hours->seconds 2) (hours->seconds 1) (hours->seconds 2)))
(assert (not (time-matches? (hours->seconds 4) (hours->seconds 1) (hours->seconds 2))))
(assert (not (time-matches? (hours->seconds 1) (hours->seconds 4) (hours->seconds 2))))