1 ;;; timezone.el --- time zone package for GNU Emacs
3 ;; Copyright (C) 1990, 1991, 1992, 1993 Free Software Foundation, Inc.
5 ;; Author: Masanobu Umeda
6 ;; Maintainer: umerin@mse.kyutech.ac.jp
9 ;; This file is part of GNU Emacs.
11 ;; GNU Emacs is free software; you can redistribute it and/or modify
12 ;; it 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 ;; GNU Emacs is distributed in the hope that it will be useful,
17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 ;; GNU General Public License for more details.
21 ;; You should have received a copy of the GNU General Public License
22 ;; along with GNU Emacs; 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.
30 (defvar timezone-world-timezones
39 ("AST" . -
400) ;by <clamen@CS.CMU.EDU>
40 ("NST" . -
330) ;by <clamen@CS.CMU.EDU>
47 ("GMT+1" .
+100) ("GMT+2" .
+200) ("GMT+3" .
+300)
48 ("GMT+4" .
+400) ("GMT+5" .
+500) ("GMT+6" .
+600)
49 ("GMT+7" .
+700) ("GMT+8" .
+800) ("GMT+9" .
+900)
50 ("GMT+10" .
+1000) ("GMT+11" .
+1100) ("GMT+12" .
+1200) ("GMT+13" .
+1300)
51 ("GMT-1" . -
100) ("GMT-2" . -
200) ("GMT-3" . -
300)
52 ("GMT-4" . -
400) ("GMT-5" . -
500) ("GMT-6" . -
600)
53 ("GMT-7" . -
700) ("GMT-8" . -
800) ("GMT-9" . -
900)
54 ("GMT-10" . -
1000) ("GMT-11" . -
1100) ("GMT-12" . -
1200))
55 "*Time differentials of timezone from GMT in +-HHMM form.
56 This list is obsolescent, and is present only for backwards compatibility,
57 because time zone names are ambiguous in practice.
58 Use `current-time-zone' instead.")
60 (defvar timezone-months-assoc
61 '(("JAN" .
1)("FEB" .
2)("MAR" .
3)
62 ("APR" .
4)("MAY" .
5)("JUN" .
6)
63 ("JUL" .
7)("AUG" .
8)("SEP" .
9)
64 ("OCT" .
10)("NOV" .
11)("DEC" .
12))
65 "Alist of first three letters of a month and its numerical representation.")
67 (defun timezone-make-date-arpa-standard (date &optional local timezone
)
68 "Convert DATE to an arpanet standard date.
69 Optional 1st argument LOCAL specifies the default local timezone of the DATE;
70 if nil, GMT is assumed.
71 Optional 2nd argument TIMEZONE specifies a time zone to be represented in;
72 if nil, the local time zone is assumed."
73 (let ((new (timezone-fix-time date local timezone
)))
74 (timezone-make-arpa-date (aref new
0) (aref new
1) (aref new
2)
75 (timezone-make-time-string
76 (aref new
3) (aref new
4) (aref new
5))
80 (defun timezone-make-date-sortable (date &optional local timezone
)
81 "Convert DATE to a sortable date string.
82 Optional 1st argument LOCAL specifies the default local timezone of the DATE;
83 if nil, GMT is assumed.
84 Optional 2nd argument TIMEZONE specifies a timezone to be represented in;
85 if nil, the local time zone is assumed."
86 (let ((new (timezone-fix-time date local timezone
)))
87 (timezone-make-sortable-date (aref new
0) (aref new
1) (aref new
2)
88 (timezone-make-time-string
89 (aref new
3) (aref new
4) (aref new
5)))
94 ;; Parsers and Constructors of Date and Time
97 (defun timezone-make-arpa-date (year month day time
&optional timezone
)
98 "Make arpanet standard date string from YEAR, MONTH, DAY, and TIME.
99 Optional argument TIMEZONE specifies a time zone."
102 (let* ((m (timezone-zone-to-minute timezone
))
103 (absm (if (< m
0) (- m
) m
)))
105 (if (< m
0) ?- ?
+) (/ absm
60) (% absm
60)))
107 (format "%02d %s %04d %s %s"
109 (capitalize (car (rassq month timezone-months-assoc
)))
114 (defun timezone-make-sortable-date (year month day time
)
115 "Make sortable date string from YEAR, MONTH, DAY, and TIME."
116 (format "%4d%02d%02d%s"
117 year month day time
))
119 (defun timezone-make-time-string (hour minute second
)
120 "Make time string from HOUR, MINUTE, and SECOND."
121 (format "%02d:%02d:%02d" hour minute second
))
123 (defun timezone-parse-date (date)
124 "Parse DATE and return a vector [YEAR MONTH DAY TIME TIMEZONE].
125 19 is prepended to year if necessary. Timezone may be nil if nothing.
126 Understands the following styles:
127 (1) 14 Apr 89 03:20[:12] [GMT]
128 (2) Fri, 17 Mar 89 4:01[:33] [GMT]
129 (3) Mon Jan 16 16:12[:37] [GMT] 1989
130 (4) 6 May 1992 1641-JST (Wednesday)
131 (5) 22-AUG-1993 10:59:12.82
132 (6) Thu, 11 Apr 16:17:12 91 [MET]
133 (7) Mon, 6 Jul 16:47:20 T 1992 [MET]"
134 ;; Get rid of any text properties.
136 (or (text-properties-at 0 date
)
137 (next-property-change 0 date
))
138 (setq date
(copy-sequence date
))
139 (set-text-properties 0 (length date
) nil date
))
140 (let ((date (or date
""))
145 (zone nil
)) ;This may be nil.
147 "\\([^ \t,]+\\),[ \t]+\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\(T[ \t]+\\|\\)\\([0-9]+\\)[ \t]*\\'" date
)
148 ;; Styles: (6) and (7) without timezone
149 (setq year
6 month
3 day
2 time
4 zone nil
))
151 "\\([^ \t,]+\\),[ \t]+\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\(T[ \t]+\\|\\)\\([0-9]+\\)[ \t]*\\([-+a-zA-Z0-9]+\\)" date
)
152 ;; Styles: (6) and (7) with timezone and buggy timezone
153 (setq year
6 month
3 day
2 time
4 zone
7))
155 "\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]*\\'" date
)
156 ;; Styles: (1) and (2) without timezone
157 (setq year
3 month
2 day
1 time
4 zone nil
))
159 "\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]*\\([-+a-zA-Z0-9]+\\)" date
)
160 ;; Styles: (1) and (2) with timezone and buggy timezone
161 (setq year
3 month
2 day
1 time
4 zone
5))
163 "\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\([0-9]+\\)" date
)
164 ;; Styles: (3) without timezone
165 (setq year
4 month
1 day
2 time
3 zone nil
))
167 "\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\([-+a-zA-Z0-9]+\\)[ \t]+\\([0-9]+\\)" date
)
168 ;; Styles: (3) with timezone
169 (setq year
5 month
1 day
2 time
3 zone
4))
171 "\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+\\)[ \t]*\\([-+a-zA-Z0-9]+\\)" date
)
172 ;; Styles: (4) with timezone
173 (setq year
3 month
2 day
1 time
4 zone
5))
175 "\\([0-9]+\\)-\\([A-Za-z]+\\)-\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9]+:[0-9]+\\)\\.[0-9]+" date
)
176 ;; Styles: (5) without timezone.
177 (setq year
3 month
2 day
1 time
4 zone nil
))
182 (substring date
(match-beginning year
) (match-end year
)))
183 ;; It is now Dec 1992. 8 years before the end of the World.
184 (if (< (length year
) 4)
185 (setq year
(concat "19" (substring year -
2 nil
))))
186 (let ((string (substring date
187 (match-beginning month
)
188 (+ (match-beginning month
) 3))))
191 (cdr (assoc (upcase string
) timezone-months-assoc
)))))
194 (substring date
(match-beginning day
) (match-end day
)))
196 (substring date
(match-beginning time
) (match-end time
)))))
199 (substring date
(match-beginning zone
) (match-end zone
))))
202 (vector year month day time zone
)
203 (vector "0" "0" "0" "0" nil
))
206 (defun timezone-parse-time (time)
207 "Parse TIME (HH:MM:SS) and return a vector [hour minute second].
208 Recognize HH:MM:SS, HH:MM, HHMMSS, HHMM."
209 (let ((time (or time
""))
213 (cond ((string-match "\\`\\([0-9]+\\):\\([0-9]+\\):\\([0-9]+\\)\\'" time
)
215 (setq hour
1 minute
2 second
3))
216 ((string-match "\\`\\([0-9]+\\):\\([0-9]+\\)\\'" time
)
218 (setq hour
1 minute
2 second nil
))
219 ((string-match "\\`\\([0-9][0-9]\\)\\([0-9][0-9]\\)\\([0-9][0-9]\\)\\'" time
)
221 (setq hour
1 minute
2 second
3))
222 ((string-match "\\`\\([0-9][0-9]\\)\\([0-9][0-9]\\)\\'" time
)
224 (setq hour
1 minute
2 second nil
))
226 ;; Return [hour minute second]
229 (substring time
(match-beginning hour
) (match-end hour
)) "0")
231 (substring time
(match-beginning minute
) (match-end minute
)) "0")
233 (substring time
(match-beginning second
) (match-end second
)) "0"))
239 (defun timezone-zone-to-minute (timezone)
240 "Translate TIMEZONE to an integer minute offset from GMT.
241 TIMEZONE can be a cons cell containing the output of current-time-zone,
242 or an integer of the form +-HHMM, or a time zone name."
245 (/ (car timezone
) 60))
249 (or (cdr (assoc (upcase timezone
) timezone-world-timezones
))
252 (if (stringp timezone
)
253 (setq timezone
(string-to-int timezone
)))
254 ;; Taking account of minute in timezone.
256 (let* ((abszone (abs timezone
))
257 (minutes (+ (* 60 (/ abszone
100)) (% abszone
100))))
258 (if (< timezone
0) (- minutes
) minutes
))))
261 (defun timezone-time-from-absolute (date seconds
)
262 "Compute the UTC time equivalent to DATE at time SECONDS after midnight.
263 Return a list suitable as an argument to current-time-zone,
264 or nil if the date cannot be thus represented.
265 DATE is the number of days elapsed since the (imaginary)
266 Gregorian date Sunday, December 31, 1 BC."
267 (let* ((current-time-origin 719162)
268 ;; (timezone-absolute-from-gregorian 1 1 1970)
269 (days (- date current-time-origin
))
270 (seconds-per-day (float 86400))
271 (seconds (+ seconds
(* days seconds-per-day
)))
272 (current-time-arithmetic-base (float 65536))
273 (hi (floor (/ seconds current-time-arithmetic-base
)))
274 (hibase (* hi current-time-arithmetic-base
))
275 (lo (floor (- seconds hibase
))))
276 (and (< (abs (- seconds
(+ hibase lo
))) 2) ;; Check for integer overflow.
279 (defun timezone-time-zone-from-absolute (date seconds
)
280 "Compute the local time zone for DATE at time SECONDS after midnight.
281 Return a list in the same format as current-time-zone's result,
282 or nil if the local time zone could not be computed.
283 DATE is the number of days elapsed since the (imaginary)
284 Gregorian date Sunday, December 31, 1 BC."
285 (and (fboundp 'current-time-zone
)
286 (let ((utc-time (timezone-time-from-absolute date seconds
)))
288 (let ((zone (current-time-zone utc-time
)))
289 (and (car zone
) zone
))))))
291 (defun timezone-fix-time (date local timezone
)
292 "Convert DATE (default timezone LOCAL) to YYYY-MM-DD-HH-MM-SS-ZONE vector.
293 If LOCAL is nil, it is assumed to be GMT.
294 If TIMEZONE is nil, use the local time zone."
295 (let* ((date (timezone-parse-date date
))
296 (year (string-to-int (aref date
0)))
297 (year (cond ((< year
50)
302 (month (string-to-int (aref date
1)))
303 (day (string-to-int (aref date
2)))
304 (time (timezone-parse-time (aref date
3)))
305 (hour (string-to-int (aref time
0)))
306 (minute (string-to-int (aref time
1)))
307 (second (string-to-int (aref time
2)))
308 (local (or (aref date
4) local
)) ;Use original if defined
311 (timezone-time-zone-from-absolute
312 (timezone-absolute-from-gregorian month day year
)
313 (+ second
(* 60 (+ minute
(* 60 hour
)))))))
314 (diff (- (timezone-zone-to-minute timezone
)
315 (timezone-zone-to-minute local
)))
316 (minute (+ minute diff
))
317 (hour-fix (floor minute
60)))
318 (setq hour
(+ hour hour-fix
))
319 (setq minute
(- minute
(* 60 hour-fix
)))
320 ;; HOUR may be larger than 24 or smaller than 0.
321 (cond ((<= 24 hour
) ;24 -> 00
322 (setq hour
(- hour
24))
324 (if (< (timezone-last-day-of-month month year
) day
)
326 (setq month
(1+ month
))
331 (setq year
(1+ year
))
335 (setq hour
(+ hour
24))
339 (setq month
(1- month
))
343 (setq year
(1- year
))
345 (setq day
(timezone-last-day-of-month month year
))
348 (vector year month day hour minute second timezone
)))
350 ;; Partly copied from Calendar program by Edward M. Reingold.
353 (defun timezone-last-day-of-month (month year
)
354 "The last day in MONTH during YEAR."
355 (if (and (= month
2) (timezone-leap-year-p year
))
357 (aref [31 28 31 30 31 30 31 31 30 31 30 31] (1- month
))))
359 (defun timezone-leap-year-p (year)
360 "Returns t if YEAR is a Gregorian leap year."
361 (or (and (zerop (% year
4))
362 (not (zerop (% year
100))))
363 (zerop (% year
400))))
365 (defun timezone-day-number (month day year
)
366 "Return the day number within the year of the date month/day/year."
367 (let ((day-of-year (+ day
(* 31 (1- month
)))))
370 (setq day-of-year
(- day-of-year
(/ (+ 23 (* 4 month
)) 10)))
371 (if (timezone-leap-year-p year
)
372 (setq day-of-year
(1+ day-of-year
)))))
375 (defun timezone-absolute-from-gregorian (month day year
)
376 "The number of days between the Gregorian date 12/31/1 BC and month/day/year.
377 The Gregorian date Sunday, December 31, 1 BC is imaginary."
378 (+ (timezone-day-number month day year
);; Days this year
379 (* 365 (1- year
));; + Days in prior years
380 (/ (1- year
) 4);; + Julian leap years
381 (- (/ (1- year
) 100));; - century years
382 (/ (1- year
) 400)));; + Gregorian leap years
384 ;;; timezone.el ends here