1 ;;; timezone.el --- time zone package for XEmacs
3 ;; Copyright (C) 1990, 1991, 1992, 1993, 1996, 1999 Free Software Foundation, Inc.
5 ;; Author: Masanobu Umeda
6 ;; Maintainer: XEmacs Development Team
9 ;; This file is part of XEmacs.
11 ;; XEmacs is free software; you can redistribute it and/or modify it
12 ;; under the terms of the GNU General Public License as published by
13 ;; the Free Software Foundation; either version 2, or (at your option)
16 ;; XEmacs is distributed in the hope that it will be useful, but
17 ;; WITHOUT ANY WARRANTY; without even the implied warranty of
18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 ;; General Public License for more details.
21 ;; You should have received a copy of the GNU General Public License
22 ;; along with XEmacs; see the file COPYING. If not, write to the
23 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
24 ;; Boston, MA 02111-1307, USA.
26 ;;; Synched up with: FSF 21.3.
30 ;; Modified 1 February 1994 by Kyle Jones to fix broken
31 ;; timezone-floor function.
33 ;; Modified 25 January 1994 by Kyle Jones so that it will
34 ;; work under version 18 of Emacs. Provided timezone-floor
35 ;; and timezone-abs functions.
39 (defvar timezone-world-timezones
48 ("AST" . -400) ;by <clamen@CS.CMU.EDU>
49 ("NST" . -330) ;by <clamen@CS.CMU.EDU>
56 ("GMT+1" . +100) ("GMT+2" . +200) ("GMT+3" . +300)
57 ("GMT+4" . +400) ("GMT+5" . +500) ("GMT+6" . +600)
58 ("GMT+7" . +700) ("GMT+8" . +800) ("GMT+9" . +900)
59 ("GMT+10" . +1000) ("GMT+11" . +1100) ("GMT+12" . +1200) ("GMT+13" . +1300)
60 ("GMT-1" . -100) ("GMT-2" . -200) ("GMT-3" . -300)
61 ("GMT-4" . -400) ("GMT-5" . -500) ("GMT-6" . -600)
62 ("GMT-7" . -700) ("GMT-8" . -800) ("GMT-9" . -900)
63 ("GMT-10" . -1000) ("GMT-11" . -1100) ("GMT-12" . -1200))
64 "*Time differentials of timezone from GMT in +-HHMM form.
65 This list is obsolescent, and is present only for backwards compatibility,
66 because time zone names are ambiguous in practice.
67 Use `current-time-zone' instead.")
69 (defvar timezone-months-assoc
70 '(("JAN" . 1)("FEB" . 2)("MAR" . 3)
71 ("APR" . 4)("MAY" . 5)("JUN" . 6)
72 ("JUL" . 7)("AUG" . 8)("SEP" . 9)
73 ("OCT" . 10)("NOV" . 11)("DEC" . 12))
74 "Alist of first three letters of a month and its numerical representation.")
76 (defun timezone-make-date-arpa-standard (date &optional local timezone)
77 "Convert DATE to an arpanet standard date.
78 Optional 2nd argument LOCAL specifies the default local timezone of the DATE;
79 if nil, GMT is assumed.
80 Optional 3rd argument TIMEZONE specifies a time zone to be represented in;
81 if nil, the local time zone is assumed."
82 (let ((new (timezone-fix-time date local timezone)))
83 (timezone-make-arpa-date (aref new 0) (aref new 1) (aref new 2)
84 (timezone-make-time-string
85 (aref new 3) (aref new 4) (aref new 5))
89 (defun timezone-make-date-sortable (date &optional local timezone)
90 "Convert DATE to a sortable date string.
91 Optional 2nd argument LOCAL specifies the default local timezone of the DATE;
92 if nil, GMT is assumed.
93 Optional 3rd argument TIMEZONE specifies a timezone to be represented in;
94 if nil, the local time zone is assumed."
95 (let ((new (timezone-fix-time date local timezone)))
96 (timezone-make-sortable-date (aref new 0) (aref new 1) (aref new 2)
97 (timezone-make-time-string
98 (aref new 3) (aref new 4) (aref new 5)))
103 ;; Parsers and Constructors of Date and Time
106 (defun timezone-make-arpa-date (year month day time &optional timezone)
107 "Make arpanet standard date string from YEAR, MONTH, DAY, and TIME.
108 Optional argument TIMEZONE specifies a time zone."
111 (let* ((m (timezone-zone-to-minute timezone))
112 (absm (if (< m 0) (- m) m)))
114 (if (< m 0) ?- ?+) (/ absm 60) (% absm 60)))
116 (format "%02d %s %04d %s %s"
118 (capitalize (car (rassq month timezone-months-assoc)))
123 (defun timezone-make-sortable-date (year month day time)
124 "Make sortable date string from YEAR, MONTH, DAY, and TIME."
125 (format "%4d%02d%02d%s"
126 year month day time))
128 (defun timezone-make-time-string (hour minute second)
129 "Make time string from HOUR, MINUTE, and SECOND."
130 (format "%02d:%02d:%02d" hour minute second))
133 (define-error 'invalid-date "Invalid date string")
135 (defun timezone-parse-date (date)
136 "Parse DATE and return a vector [YEAR MONTH DAY TIME TIMEZONE].
137 Two-digit dates are `windowed'. Those <69 have 2000 added; otherwise 1900
138 is added. Three-digit dates have 1900 added.
139 TIMEZONE is nil for DATEs without a zone field.
141 Understands the following styles:
142 (1) 14 Apr 89 03:20[:12] [GMT]
143 (2) Fri, 17 Mar 89 4:01[:33] [GMT]
144 (3) Mon Jan 16 16:12[:37] [GMT] 1989
145 (4) 6 May 1992 1641-JST (Wednesday)
146 (5) 22-AUG-1993 10:59:12.82
147 (6) Thu, 11 Apr 16:17:12 91 [MET]
148 (7) Mon, 6 Jul 16:47:20 T 1992 [MET]
149 (8) 1996-06-24 21:13:12 [GMT]
150 (9) 1996-06-24 21:13-ZONE"
151 ;; XEmacs addition: surround with condition-case
154 ;; Get rid of any text properties.
156 (or (text-properties-at 0 date)
157 (next-property-change 0 date))
158 (setq date (copy-sequence date))
159 (set-text-properties 0 (length date) nil date))
160 (let ((date (or date ""))
165 (zone nil)) ;This may be nil.
167 "\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]*\\([-+a-zA-Z0-9]+\\)" date)
168 ;; Styles: (1) and (2) with timezone and buggy timezone
169 ;; This is most common in mail and news,
170 ;; so it is worth trying first.
171 (setq year 3 month 2 day 1 time 4 zone 5))
173 "\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]*\\'" date)
174 ;; Styles: (1) and (2) without timezone
175 (setq year 3 month 2 day 1 time 4 zone nil))
177 "\\([^ \t,]+\\),[ \t]+\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\(T[ \t]+\\|\\)\\([0-9]+\\)[ \t]*\\'" date)
178 ;; Styles: (6) and (7) without timezone
179 (setq year 6 month 3 day 2 time 4 zone nil))
181 "\\([^ \t,]+\\),[ \t]+\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\(T[ \t]+\\|\\)\\([0-9]+\\)[ \t]*\\([-+a-zA-Z0-9]+\\)" date)
182 ;; Styles: (6) and (7) with timezone and buggy timezone
183 (setq year 6 month 3 day 2 time 4 zone 7))
185 "\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\([0-9]+\\)" date)
186 ;; Styles: (3) without timezone
187 (setq year 4 month 1 day 2 time 3 zone nil))
189 "\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\([-+a-zA-Z0-9]+\\)[ \t]+\\([0-9]+\\)" date)
190 ;; Styles: (3) with timezone
191 (setq year 5 month 1 day 2 time 3 zone 4))
193 "\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+\\)[ \t]*\\([-+a-zA-Z0-9]+\\)" date)
194 ;; Styles: (4) with timezone
195 (setq year 3 month 2 day 1 time 4 zone 5))
197 "\\([0-9]+\\)-\\([A-Za-z]+\\)-\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9]+:[0-9]+\\)\\(\\.[0-9]+\\)?[ \t]+\\([-+a-zA-Z0-9]+\\)" date)
198 ;; Styles: (5) with timezone.
199 (setq year 3 month 2 day 1 time 4 zone 6))
201 "\\([0-9]+\\)-\\([A-Za-z]+\\)-\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9]+:[0-9]+\\)\\(\\.[0-9]+\\)?" date)
202 ;; Styles: (5) without timezone.
203 (setq year 3 month 2 day 1 time 4 zone nil))
205 "\\([0-9]+\\)-\\([0-9]+\\)-\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9]+:[0-9]+\\)[ \t]+\\([-+a-zA-Z0-9]+\\)" date)
206 ;; Styles: (8) with timezone.
207 (setq year 1 month 2 day 3 time 4 zone 5))
209 "\\([0-9]+\\)-\\([0-9]+\\)-\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9]+\\)[ \t]+\\([-+a-zA-Z0-9:]+\\)" date)
210 ;; Styles: (8) with timezone with a colon in it.
211 (setq year 1 month 2 day 3 time 4 zone 5))
213 "\\([0-9]+\\)-\\([0-9]+\\)-\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9]+:[0-9]+\\)" date)
214 ;; Styles: (8) without timezone.
215 (setq year 1 month 2 day 3 time 4 zone nil))
218 (setq year (match-string year date))
219 ;; Guess ambiguous years. Assume years < 69 don't predate the
220 ;; Unix Epoch, so are 2000+. Three-digit years are assumed to
221 ;; be relative to 1900.
222 (if (< (length year) 4)
223 (let ((y (string-to-int year)))
226 (setq year (int-to-string (+ 1900 y)))))
228 (if (= (aref date (+ (match-beginning month) 2)) ?-)
229 ;; Handle numeric months, spanning exactly two digits.
231 (match-beginning month)
232 (+ (match-beginning month) 2))
233 (let* ((string (substring date
234 (match-beginning month)
235 (+ (match-beginning month) 3)))
237 (cdr (assoc (upcase string) timezone-months-assoc))))
239 (int-to-string monthnum)))))
240 (setq day (match-string day date))
241 (setq time (match-string time date)))
242 (if zone (setq zone (match-string zone date)))
245 (vector year month day time zone)
246 (vector "0" "0" "0" "0" nil))))
247 (t (signal 'invalid-date (list date)))))
249 (defun timezone-parse-time (time)
250 "Parse TIME (HH:MM:SS) and return a vector [hour minute second].
251 Recognize HH:MM:SS, HH:MM, HHMMSS, HHMM."
252 (let ((time (or time ""))
254 (cond ((string-match "\\`\\([0-9]+\\):\\([0-9]+\\):\\([0-9]+\\)\\'" time)
256 (setq hour 1 minute 2 second 3))
257 ((string-match "\\`\\([0-9]+\\):\\([0-9]+\\)\\'" time)
259 (setq hour 1 minute 2 second nil))
260 ((string-match "\\`\\([0-9][0-9]\\)\\([0-9][0-9]\\)\\([0-9][0-9]\\)\\'" time)
262 (setq hour 1 minute 2 second 3))
263 ((string-match "\\`\\([0-9][0-9]\\)\\([0-9][0-9]\\)\\'" time)
265 (setq hour 1 minute 2 second nil))
267 ;; Return [hour minute second]
269 (if hour (match-string hour time) "0")
270 (if minute (match-string minute time) "0")
271 (if second (match-string second time) "0"))))
276 (defun timezone-zone-to-minute (timezone)
277 "Translate TIMEZONE to an integer minute offset from GMT.
278 TIMEZONE can be a cons cell containing the output of current-time-zone,
279 or an integer of the form +-HHMM, or a time zone name."
282 (/ (car timezone) 60))
286 (or (and (stringp timezone) (cdr (assoc (upcase timezone) timezone-world-timezones)))
289 (if (stringp timezone)
290 (setq timezone (string-to-int timezone)))
291 ;; Taking account of minute in timezone.
293 (let* ((abszone (timezone-abs timezone))
294 (minutes (+ (* 60 (/ abszone 100)) (% abszone 100))))
295 (if (< timezone 0) (- minutes) minutes))))
298 (defun timezone-time-from-absolute (date seconds)
299 "Compute the UTC time equivalent to DATE at time SECONDS after midnight.
300 Return a list suitable as an argument to current-time-zone,
301 or nil if the date cannot be thus represented.
302 DATE is the number of days elapsed since the (imaginary)
303 Gregorian date Sunday, December 31, 1 BC."
304 (let* ((current-time-origin 719163)
305 ;; (timezone-absolute-from-gregorian 1 1 1970)
306 (days (- date current-time-origin))
307 (seconds-per-day (float 86400))
308 (seconds (+ seconds (* days seconds-per-day)))
309 (current-time-arithmetic-base (float 65536))
310 (hi (timezone-floor (/ seconds current-time-arithmetic-base)))
311 (hibase (* hi current-time-arithmetic-base))
312 (lo (timezone-floor (- seconds hibase))))
313 (and (< (timezone-abs (- seconds (+ hibase lo))) 2) ;; Check for integer overflow.
316 (defun timezone-time-zone-from-absolute (date seconds)
317 "Compute the local time zone for DATE at time SECONDS after midnight.
318 Return a list in the same format as current-time-zone's result,
319 or nil if the local time zone could not be computed.
320 DATE is the number of days elapsed since the (imaginary)
321 Gregorian date Sunday, December 31, 1 BC."
322 (and (fboundp 'current-time-zone)
323 (let ((utc-time (timezone-time-from-absolute date seconds)))
325 (let ((zone (current-time-zone utc-time)))
326 (and (car zone) zone))))))
328 (defun timezone-fix-time (date local timezone)
329 "Convert DATE (default timezone LOCAL) to YYYY-MM-DD-HH-MM-SS-ZONE vector.
330 If LOCAL is nil, it is assumed to be GMT.
331 If TIMEZONE is nil, use the local time zone."
332 (let* ((date (timezone-parse-date date))
333 (year (string-to-int (aref date 0)))
334 (year (cond ((< year 69)
338 ((< year 1000) ; possible 3-digit years.
341 (month (string-to-int (aref date 1)))
342 (day (string-to-int (aref date 2)))
343 (time (timezone-parse-time (aref date 3)))
344 (hour (string-to-int (aref time 0)))
345 (minute (string-to-int (aref time 1)))
346 (second (string-to-int (aref time 2)))
347 (local (or (aref date 4) local)) ;Use original if defined
350 (timezone-time-zone-from-absolute
351 (timezone-absolute-from-gregorian month day year)
352 (+ second (* 60 (+ minute (* 60 hour)))))))
353 (diff (- (timezone-zone-to-minute timezone)
354 (timezone-zone-to-minute local)))
355 (minute (+ minute diff))
356 (hour-fix (timezone-floor minute 60)))
357 (setq hour (+ hour hour-fix))
358 (setq minute (- minute (* 60 hour-fix)))
359 ;; HOUR may be larger than 24 or smaller than 0.
360 (cond ((<= 24 hour) ;24 -> 00
361 (setq hour (- hour 24))
363 (when (< (timezone-last-day-of-month month year) day)
364 (setq month (1+ month))
368 (setq year (1+ year)))))
370 (setq hour (+ hour 24))
373 (setq month (1- month))
376 (setq year (1- year)))
377 (setq day (timezone-last-day-of-month month year)))))
378 (vector year month day hour minute second timezone)))
380 ;; Partly copied from Calendar program by Edward M. Reingold.
383 (defun timezone-last-day-of-month (month year)
384 "The last day in MONTH during YEAR."
385 (if (and (= month 2) (timezone-leap-year-p year))
387 (aref [31 28 31 30 31 30 31 31 30 31 30 31] (1- month))))
389 (defun timezone-leap-year-p (year)
390 "Returns t if YEAR is a Gregorian leap year."
391 (or (and (zerop (% year 4))
392 (not (zerop (% year 100))))
393 (zerop (% year 400))))
395 (defun timezone-day-number (month day year)
396 "Return the day number within the year of the date month/day/year."
397 (let ((day-of-year (+ day (* 31 (1- month)))))
400 (setq day-of-year (- day-of-year (/ (+ 23 (* 4 month)) 10)))
401 (if (timezone-leap-year-p year)
402 (setq day-of-year (1+ day-of-year)))))
405 (defun timezone-absolute-from-gregorian (month day year)
406 "The number of days between the Gregorian date 12/31/1 BC and month/day/year.
407 The Gregorian date Sunday, December 31, 1 BC is imaginary."
408 (+ (timezone-day-number month day year);; Days this year
409 (* 365 (1- year));; + Days in prior years
410 (/ (1- year) 4);; + Julian leap years
411 (- (/ (1- year) 100));; - century years
412 (/ (1- year) 400)));; + Gregorian leap years
414 (defun timezone-abs (n)
417 (if (< n 0) (- n) n)))
419 (defun timezone-floor (n &optional divisor)
425 (- (/ (- divisor 1 n) divisor))
430 ;;; timezone.el ends here