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| author | Gerd Moellmann <gerd@gnu.org> | 2000-09-19 13:40:08 +0000 |
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| committer | Gerd Moellmann <gerd@gnu.org> | 2000-09-19 13:40:08 +0000 |
| commit | c113de23613952ed67a3bca79363b30ab7e406c3 (patch) | |
| tree | fd8063340169da2af53fa73046debd7a220904ac /lisp/gnus/time-date.el | |
| parent | 16409b0bb832ae376894cbad5892bf7623caeaaf (diff) | |
| download | emacs-c113de23613952ed67a3bca79363b30ab7e406c3.tar.gz emacs-c113de23613952ed67a3bca79363b30ab7e406c3.tar.bz2 emacs-c113de23613952ed67a3bca79363b30ab7e406c3.zip | |
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Diffstat (limited to 'lisp/gnus/time-date.el')
| -rw-r--r-- | lisp/gnus/time-date.el | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/lisp/gnus/time-date.el b/lisp/gnus/time-date.el new file mode 100644 index 00000000000..ba7f81a1ed1 --- /dev/null +++ b/lisp/gnus/time-date.el @@ -0,0 +1,132 @@ +;;; time-date.el --- Date and time handling functions +;; Copyright (C) 1998, 1999, 2000 Free Software Foundation, Inc. + +;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org> +;; Masanobu Umeda <umerin@mse.kyutech.ac.jp> +;; Keywords: mail news util + +;; This file is part of GNU Emacs. + +;; GNU Emacs is free software; you can redistribute it and/or modify +;; it under the terms of the GNU General Public License as published by +;; the Free Software Foundation; either version 2, or (at your option) +;; any later version. + +;; GNU Emacs 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 General Public License for more details. + +;; You should have received a copy of the GNU General Public License +;; along with GNU Emacs; see the file COPYING. If not, write to the +;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, +;; Boston, MA 02111-1307, USA. + +;;; Commentary: + +;;; Code: + +(require 'parse-time) + +;;;###autoload +(defun date-to-time (date) + "Convert DATE into time." + (condition-case () + (apply 'encode-time (parse-time-string date)) + (error (error "Invalid date: %s" date)))) + +(defun time-to-seconds (time) + "Convert TIME to a floating point number." + (+ (* (car time) 65536.0) + (cadr time) + (/ (or (nth 2 time) 0) 1000000.0))) + +(defun seconds-to-time (seconds) + "Convert SECONDS (a floating point number) to an Emacs time structure." + (list (floor seconds 65536) + (floor (mod seconds 65536)) + (floor (* (- seconds (ffloor seconds)) 1000000)))) + +(defun time-less-p (t1 t2) + "Say whether time T1 is less than time T2." + (or (< (car t1) (car t2)) + (and (= (car t1) (car t2)) + (< (nth 1 t1) (nth 1 t2))))) + +(defun days-to-time (days) + "Convert DAYS into time." + (let* ((seconds (* 1.0 days 60 60 24)) + (rest (expt 2 16)) + (ms (condition-case nil (floor (/ seconds rest)) + (range-error (expt 2 16))))) + (list ms (condition-case nil (round (- seconds (* ms rest))) + (range-error (expt 2 16)))))) + +(defun time-since (time) + "Return the time since TIME, which is either an internal time or a date." + (when (stringp time) + ;; Convert date strings to internal time. + (setq time (date-to-time time))) + (let* ((current (current-time)) + (rest (when (< (nth 1 current) (nth 1 time)) + (expt 2 16)))) + (list (- (+ (car current) (if rest -1 0)) (car time)) + (- (+ (or rest 0) (nth 1 current)) (nth 1 time))))) + +(defun subtract-time (t1 t2) + "Subtract two internal times." + (let ((borrow (< (cadr t1) (cadr t2)))) + (list (- (car t1) (car t2) (if borrow 1 0)) + (- (+ (if borrow 65536 0) (cadr t1)) (cadr t2))))) + +(defun date-to-day (date) + "Return the number of days between year 1 and DATE." + (time-to-days (date-to-time date))) + +(defun days-between (date1 date2) + "Return the number of days between DATE1 and DATE2." + (- (date-to-day date1) (date-to-day date2))) + +(defun date-leap-year-p (year) + "Return t if YEAR is a leap year." + (or (and (zerop (% year 4)) + (not (zerop (% year 100)))) + (zerop (% year 400)))) + +(defun time-to-day-in-year (time) + "Return the day number within the year of the date month/day/year." + (let* ((tim (decode-time time)) + (month (nth 4 tim)) + (day (nth 3 tim)) + (year (nth 5 tim)) + (day-of-year (+ day (* 31 (1- month))))) + (when (> month 2) + (setq day-of-year (- day-of-year (/ (+ 23 (* 4 month)) 10))) + (when (date-leap-year-p year) + (setq day-of-year (1+ day-of-year)))) + day-of-year)) + +(defun time-to-days (time) + "The number of days between the Gregorian date 0001-12-31bce and TIME. +The Gregorian date Sunday, December 31, 1bce is imaginary." + (let* ((tim (decode-time time)) + (month (nth 4 tim)) + (day (nth 3 tim)) + (year (nth 5 tim))) + (+ (time-to-day-in-year time) ; Days this year + (* 365 (1- year)) ; + Days in prior years + (/ (1- year) 4) ; + Julian leap years + (- (/ (1- year) 100)) ; - century years + (/ (1- year) 400)))) ; + Gregorian leap years + +;;;###autoload +(defun safe-date-to-time (date) + "Parse DATE and return a time structure. +If DATE is malformed, a zero time will be returned." + (condition-case () + (date-to-time date) + (error '(0 0)))) + +(provide 'time-date) + +;;; time-date.el ends here |