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1 ;;; timezone.el --- time zone package for GNU Emacs
2
3 ;; Copyright (C) 1990, 1991, 1992, 1993 Free Software Foundation, Inc.
4
5 ;; Author: Masanobu Umeda
6 ;; Maintainer: umerin@mse.kyutech.ac.jp
7 ;; Keywords: news
8
9 ;; This file is part of XEmacs.
10
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)
14 ;; any later version.
15
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.
20
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 Free
23 ;; Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
24
25 ;;; Synched up with: FSF 19.30.
26
27 ;; Modified 1 February 1994 by Kyle Jones to fix broken
28 ;; timezone-floor function.
29
30 ;; Modified 25 January 1994 by Kyle Jones so that it will
31 ;; work under version 18 of Emacs. Provided timezone-floor
32 ;; and timezone-abs functions.
33
34 ;;; Code:
35
36 (provide 'timezone)
37
38 (defvar timezone-world-timezones
39 '(("PST" . -800)
40 ("PDT" . -700)
41 ("MST" . -700)
42 ("MDT" . -600)
43 ("CST" . -600)
44 ("CDT" . -500)
45 ("EST" . -500)
46 ("EDT" . -400)
47 ("AST" . -400) ;by <clamen@CS.CMU.EDU>
48 ("NST" . -330) ;by <clamen@CS.CMU.EDU>
49 ("UT" . +000)
50 ("GMT" . +000)
51 ("BST" . +100)
52 ("MET" . +100)
53 ("EET" . +200)
54 ("JST" . +900)
55 ("GMT+1" . +100) ("GMT+2" . +200) ("GMT+3" . +300)
56 ("GMT+4" . +400) ("GMT+5" . +500) ("GMT+6" . +600)
57 ("GMT+7" . +700) ("GMT+8" . +800) ("GMT+9" . +900)
58 ("GMT+10" . +1000) ("GMT+11" . +1100) ("GMT+12" . +1200) ("GMT+13" . +1300)
59 ("GMT-1" . -100) ("GMT-2" . -200) ("GMT-3" . -300)
60 ("GMT-4" . -400) ("GMT-5" . -500) ("GMT-6" . -600)
61 ("GMT-7" . -700) ("GMT-8" . -800) ("GMT-9" . -900)
62 ("GMT-10" . -1000) ("GMT-11" . -1100) ("GMT-12" . -1200))
63 "*Time differentials of timezone from GMT in +-HHMM form.
64 This list is obsolescent, and is present only for backwards compatibility,
65 because time zone names are ambiguous in practice.
66 Use `current-time-zone' instead.")
67
68 (defvar timezone-months-assoc
69 '(("JAN" . 1)("FEB" . 2)("MAR" . 3)
70 ("APR" . 4)("MAY" . 5)("JUN" . 6)
71 ("JUL" . 7)("AUG" . 8)("SEP" . 9)
72 ("OCT" . 10)("NOV" . 11)("DEC" . 12))
73 "Alist of first three letters of a month and its numerical representation.")
74
75 (defun timezone-make-date-arpa-standard (date &optional local timezone)
76 "Convert DATE to an arpanet standard date.
77 Optional 1st argument LOCAL specifies the default local timezone of the DATE;
78 if nil, GMT is assumed.
79 Optional 2nd argument TIMEZONE specifies a time zone to be represented in;
80 if nil, the local time zone is assumed."
81 (let ((new (timezone-fix-time date local timezone)))
82 (timezone-make-arpa-date (aref new 0) (aref new 1) (aref new 2)
83 (timezone-make-time-string
84 (aref new 3) (aref new 4) (aref new 5))
85 (aref new 6))
86 ))
87
88 (defun timezone-make-date-sortable (date &optional local timezone)
89 "Convert DATE to a sortable date string.
90 Optional 1st argument LOCAL specifies the default local timezone of the DATE;
91 if nil, GMT is assumed.
92 Optional 2nd argument TIMEZONE specifies a timezone to be represented in;
93 if nil, the local time zone is assumed."
94 (let ((new (timezone-fix-time date local timezone)))
95 (timezone-make-sortable-date (aref new 0) (aref new 1) (aref new 2)
96 (timezone-make-time-string
97 (aref new 3) (aref new 4) (aref new 5)))
98 ))
99
100
101 ;;
102 ;; Parsers and Constructors of Date and Time
103 ;;
104
105 (defun timezone-make-arpa-date (year month day time &optional timezone)
106 "Make arpanet standard date string from YEAR, MONTH, DAY, and TIME.
107 Optional argument TIMEZONE specifies a time zone."
108 (let ((zone
109 (if (listp timezone)
110 (let* ((m (timezone-zone-to-minute timezone))
111 (absm (if (< m 0) (- m) m)))
112 (format "%c%02d%02d"
113 (if (< m 0) ?- ?+) (/ absm 60) (% absm 60)))
114 timezone)))
115 (format "%02d %s %04d %s %s"
116 day
117 (capitalize (car (rassq month timezone-months-assoc)))
118 year
119 time
120 zone)))
121
122 (defun timezone-make-sortable-date (year month day time)
123 "Make sortable date string from YEAR, MONTH, DAY, and TIME."
124 (format "%4d%02d%02d%s"
125 year month day time))
126
127 (defun timezone-make-time-string (hour minute second)
128 "Make time string from HOUR, MINUTE, and SECOND."
129 (format "%02d:%02d:%02d" hour minute second))
130
131 (defun timezone-parse-date (date)
132 "Parse DATE and return a vector [YEAR MONTH DAY TIME TIMEZONE].
133 19 is prepended to year if necessary. Timezone may be nil if nothing.
134 Understands the following styles:
135 (1) 14 Apr 89 03:20[:12] [GMT]
136 (2) Fri, 17 Mar 89 4:01[:33] [GMT]
137 (3) Mon Jan 16 16:12[:37] [GMT] 1989
138 (4) 6 May 1992 1641-JST (Wednesday)
139 (5) 22-AUG-1993 10:59:12.82
140 (6) Thu, 11 Apr 16:17:12 91 [MET]
141 (7) Mon, 6 Jul 16:47:20 T 1992 [MET]"
142 ;; Get rid of any text properties.
143 (and (stringp date)
144 (or (text-properties-at 0 date)
145 (next-property-change 0 date))
146 (setq date (copy-sequence date))
147 (set-text-properties 0 (length date) nil date))
148 (let ((date (or date ""))
149 (year nil)
150 (month nil)
151 (day nil)
152 (time nil)
153 (zone nil)) ;This may be nil.
154 (cond ((string-match
155 "\\([^ \t,]+\\),[ \t]+\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\(T[ \t]+\\|\\)\\([0-9]+\\)[ \t]*\\'" date)
156 ;; Styles: (6) and (7) without timezone
157 (setq year 6 month 3 day 2 time 4 zone nil))
158 ((string-match
159 "\\([^ \t,]+\\),[ \t]+\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\(T[ \t]+\\|\\)\\([0-9]+\\)[ \t]*\\([-+a-zA-Z0-9]+\\)" date)
160 ;; Styles: (6) and (7) with timezone and buggy timezone
161 (setq year 6 month 3 day 2 time 4 zone 7))
162 ((string-match
163 "\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]*\\'" date)
164 ;; Styles: (1) and (2) without timezone
165 (setq year 3 month 2 day 1 time 4 zone nil))
166 ((string-match
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 (setq year 3 month 2 day 1 time 4 zone 5))
170 ((string-match
171 "\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\([0-9]+\\)" date)
172 ;; Styles: (3) without timezone
173 (setq year 4 month 1 day 2 time 3 zone nil))
174 ((string-match
175 "\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\([-+a-zA-Z0-9]+\\)[ \t]+\\([0-9]+\\)" date)
176 ;; Styles: (3) with timezone
177 (setq year 5 month 1 day 2 time 3 zone 4))
178 ((string-match
179 "\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+\\)[ \t]*\\([-+a-zA-Z0-9]+\\)" date)
180 ;; Styles: (4) with timezone
181 (setq year 3 month 2 day 1 time 4 zone 5))
182 ((string-match
183 "\\([0-9]+\\)-\\([A-Za-z]+\\)-\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9]+:[0-9]+\\)\\.[0-9]+" date)
184 ;; Styles: (5) without timezone.
185 (setq year 3 month 2 day 1 time 4 zone nil))
186 )
187 (if year
188 (progn
189 (setq year
190 (substring date (match-beginning year) (match-end year)))
191 ;; It is now Dec 1992. 8 years before the end of the World.
192 (if (< (length year) 4)
193 (setq year (concat "19" (substring year -2 nil))))
194 (let ((string (substring date
195 (match-beginning month)
196 (+ (match-beginning month) 3))))
197 (setq month
198 (int-to-string
199 (cdr (assoc (upcase string) timezone-months-assoc)))))
200
201 (setq day
202 (substring date (match-beginning day) (match-end day)))
203 (setq time
204 (substring date (match-beginning time) (match-end time)))))
205 (if zone
206 (setq zone
207 (substring date (match-beginning zone) (match-end zone))))
208 ;; Return a vector.
209 (if year
210 (vector year month day time zone)
211 (vector "0" "0" "0" "0" nil))
212 ))
213
214 (defun timezone-parse-time (time)
215 "Parse TIME (HH:MM:SS) and return a vector [hour minute second].
216 Recognize HH:MM:SS, HH:MM, HHMMSS, HHMM."
217 (let ((time (or time ""))
218 (hour nil)
219 (minute nil)
220 (second nil))
221 (cond ((string-match "\\`\\([0-9]+\\):\\([0-9]+\\):\\([0-9]+\\)\\'" time)
222 ;; HH:MM:SS
223 (setq hour 1 minute 2 second 3))
224 ((string-match "\\`\\([0-9]+\\):\\([0-9]+\\)\\'" time)
225 ;; HH:MM
226 (setq hour 1 minute 2 second nil))
227 ((string-match "\\`\\([0-9][0-9]\\)\\([0-9][0-9]\\)\\([0-9][0-9]\\)\\'" time)
228 ;; HHMMSS
229 (setq hour 1 minute 2 second 3))
230 ((string-match "\\`\\([0-9][0-9]\\)\\([0-9][0-9]\\)\\'" time)
231 ;; HHMM
232 (setq hour 1 minute 2 second nil))
233 )
234 ;; Return [hour minute second]
235 (vector
236 (if hour
237 (substring time (match-beginning hour) (match-end hour)) "0")
238 (if minute
239 (substring time (match-beginning minute) (match-end minute)) "0")
240 (if second
241 (substring time (match-beginning second) (match-end second)) "0"))
242 ))
243
244
245 ;; Miscellaneous
246
247 (defun timezone-zone-to-minute (timezone)
248 "Translate TIMEZONE to an integer minute offset from GMT.
249 TIMEZONE can be a cons cell containing the output of current-time-zone,
250 or an integer of the form +-HHMM, or a time zone name."
251 (cond
252 ((consp timezone)
253 (/ (car timezone) 60))
254 (timezone
255 (progn
256 (setq timezone
257 (or (cdr (assoc (upcase timezone) timezone-world-timezones))
258 ;; +900
259 timezone))
260 (if (stringp timezone)
261 (setq timezone (string-to-int timezone)))
262 ;; Taking account of minute in timezone.
263 ;; HHMM -> MM
264 (let* ((abszone (timezone-abs timezone))
265 (minutes (+ (* 60 (/ abszone 100)) (% abszone 100))))
266 (if (< timezone 0) (- minutes) minutes))))
267 (t 0)))
268
269 (defun timezone-time-from-absolute (date seconds)
270 "Compute the UTC time equivalent to DATE at time SECONDS after midnight.
271 Return a list suitable as an argument to current-time-zone,
272 or nil if the date cannot be thus represented.
273 DATE is the number of days elapsed since the (imaginary)
274 Gregorian date Sunday, December 31, 1 BC."
275 (let* ((current-time-origin 719162)
276 ;; (timezone-absolute-from-gregorian 1 1 1970)
277 (days (- date current-time-origin))
278 (seconds-per-day (float 86400))
279 (seconds (+ seconds (* days seconds-per-day)))
280 (current-time-arithmetic-base (float 65536))
281 (hi (timezone-floor (/ seconds current-time-arithmetic-base)))
282 (hibase (* hi current-time-arithmetic-base))
283 (lo (timezone-floor (- seconds hibase))))
284 (and (< (timezone-abs (- seconds (+ hibase lo))) 2) ;; Check for integer overflow.
285 (cons hi lo))))
286
287 (defun timezone-time-zone-from-absolute (date seconds)
288 "Compute the local time zone for DATE at time SECONDS after midnight.
289 Return a list in the same format as current-time-zone's result,
290 or nil if the local time zone could not be computed.
291 DATE is the number of days elapsed since the (imaginary)
292 Gregorian date Sunday, December 31, 1 BC."
293 (and (fboundp 'current-time-zone)
294 (let ((utc-time (timezone-time-from-absolute date seconds)))
295 (and utc-time
296 (let ((zone (current-time-zone utc-time)))
297 (and (car zone) zone))))))
298
299 (defun timezone-fix-time (date local timezone)
300 "Convert DATE (default timezone LOCAL) to YYYY-MM-DD-HH-MM-SS-ZONE vector.
301 If LOCAL is nil, it is assumed to be GMT.
302 If TIMEZONE is nil, use the local time zone."
303 (let* ((date (timezone-parse-date date))
304 (year (string-to-int (aref date 0)))
305 (year (cond ((< year 50)
306 (+ year 2000))
307 ((< year 100)
308 (+ year 1900))
309 (t year)))
310 (month (string-to-int (aref date 1)))
311 (day (string-to-int (aref date 2)))
312 (time (timezone-parse-time (aref date 3)))
313 (hour (string-to-int (aref time 0)))
314 (minute (string-to-int (aref time 1)))
315 (second (string-to-int (aref time 2)))
316 (local (or (aref date 4) local)) ;Use original if defined
317 (timezone
318 (or timezone
319 (timezone-time-zone-from-absolute
320 (timezone-absolute-from-gregorian month day year)
321 (+ second (* 60 (+ minute (* 60 hour)))))))
322 (diff (- (timezone-zone-to-minute timezone)
323 (timezone-zone-to-minute local)))
324 (minute (+ minute diff))
325 (hour-fix (timezone-floor minute 60)))
326 (setq hour (+ hour hour-fix))
327 (setq minute (- minute (* 60 hour-fix)))
328 ;; HOUR may be larger than 24 or smaller than 0.
329 (cond ((<= 24 hour) ;24 -> 00
330 (setq hour (- hour 24))
331 (setq day (1+ day))
332 (if (< (timezone-last-day-of-month month year) day)
333 (progn
334 (setq month (1+ month))
335 (setq day 1)
336 (if (< 12 month)
337 (progn
338 (setq month 1)
339 (setq year (1+ year))
340 ))
341 )))
342 ((> 0 hour)
343 (setq hour (+ hour 24))
344 (setq day (1- day))
345 (if (> 1 day)
346 (progn
347 (setq month (1- month))
348 (if (> 1 month)
349 (progn
350 (setq month 12)
351 (setq year (1- year))
352 ))
353 (setq day (timezone-last-day-of-month month year))
354 )))
355 )
356 (vector year month day hour minute second timezone)))
357
358 ;; Partly copied from Calendar program by Edward M. Reingold.
359 ;; Thanks a lot.
360
361 (defun timezone-last-day-of-month (month year)
362 "The last day in MONTH during YEAR."
363 (if (and (= month 2) (timezone-leap-year-p year))
364 29
365 (aref [31 28 31 30 31 30 31 31 30 31 30 31] (1- month))))
366
367 (defun timezone-leap-year-p (year)
368 "Returns t if YEAR is a Gregorian leap year."
369 (or (and (zerop (% year 4))
370 (not (zerop (% year 100))))
371 (zerop (% year 400))))
372
373 (defun timezone-day-number (month day year)
374 "Return the day number within the year of the date month/day/year."
375 (let ((day-of-year (+ day (* 31 (1- month)))))
376 (if (> month 2)
377 (progn
378 (setq day-of-year (- day-of-year (/ (+ 23 (* 4 month)) 10)))
379 (if (timezone-leap-year-p year)
380 (setq day-of-year (1+ day-of-year)))))
381 day-of-year))
382
383 (defun timezone-absolute-from-gregorian (month day year)
384 "The number of days between the Gregorian date 12/31/1 BC and month/day/year.
385 The Gregorian date Sunday, December 31, 1 BC is imaginary."
386 (+ (timezone-day-number month day year);; Days this year
387 (* 365 (1- year));; + Days in prior years
388 (/ (1- year) 4);; + Julian leap years
389 (- (/ (1- year) 100));; - century years
390 (/ (1- year) 400)));; + Gregorian leap years
391
392 (defun timezone-abs (n)
393 (if (fboundp 'abs)
394 (abs n)
395 (if (< n 0) (- n) n)))
396
397 (defun timezone-floor (n &optional divisor)
398 (if (fboundp 'floor)
399 (floor n divisor)
400 (if (null divisor)
401 (setq divisor 1))
402 (if (< n 0)
403 (- (/ (- divisor 1 n) divisor))
404 (/ n divisor))))
405
406 ;;; timezone.el ends here