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be010748 | 1 | ;;; timezone.el --- time zone package for GNU Emacs |
a47a5be5 | 2 | |
8601c0da | 3 | ;; Copyright (C) 1990, 1991, 1992, 1993, 1996, 1999 Free Software Foundation, Inc. |
aa56d805 | 4 | |
be010748 RS |
5 | ;; Author: Masanobu Umeda |
6 | ;; Maintainer: umerin@mse.kyutech.ac.jp | |
7 | ;; Keywords: news | |
a47a5be5 RS |
8 | |
9 | ;; This file is part of GNU Emacs. | |
10 | ||
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) | |
14 | ;; any later version. | |
15 | ||
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. | |
20 | ||
21 | ;; You should have received a copy of the GNU General Public License | |
b578f267 EN |
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. | |
a47a5be5 | 25 | |
e8af40ee PJ |
26 | ;;; Commentary: |
27 | ||
a47a5be5 RS |
28 | ;;; Code: |
29 | ||
a47a5be5 RS |
30 | (defvar timezone-world-timezones |
31 | '(("PST" . -800) | |
32 | ("PDT" . -700) | |
33 | ("MST" . -700) | |
34 | ("MDT" . -600) | |
35 | ("CST" . -600) | |
36 | ("CDT" . -500) | |
37 | ("EST" . -500) | |
38 | ("EDT" . -400) | |
39 | ("AST" . -400) ;by <clamen@CS.CMU.EDU> | |
40 | ("NST" . -330) ;by <clamen@CS.CMU.EDU> | |
dbc6c26a | 41 | ("UT" . +000) |
a47a5be5 RS |
42 | ("GMT" . +000) |
43 | ("BST" . +100) | |
44 | ("MET" . +100) | |
45 | ("EET" . +200) | |
46 | ("JST" . +900) | |
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)) | |
d51c3cda RS |
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.") | |
a47a5be5 RS |
59 | |
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.") | |
66 | ||
67 | (defun timezone-make-date-arpa-standard (date &optional local timezone) | |
68 | "Convert DATE to an arpanet standard date. | |
a184d9bf | 69 | Optional 2nd argument LOCAL specifies the default local timezone of the DATE; |
d51c3cda | 70 | if nil, GMT is assumed. |
a184d9bf | 71 | Optional 3rd argument TIMEZONE specifies a time zone to be represented in; |
d51c3cda RS |
72 | if nil, the local time zone is assumed." |
73 | (let ((new (timezone-fix-time date local timezone))) | |
a47a5be5 RS |
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)) | |
d51c3cda | 77 | (aref new 6)) |
a47a5be5 RS |
78 | )) |
79 | ||
80 | (defun timezone-make-date-sortable (date &optional local timezone) | |
81 | "Convert DATE to a sortable date string. | |
a184d9bf | 82 | Optional 2nd argument LOCAL specifies the default local timezone of the DATE; |
d51c3cda | 83 | if nil, GMT is assumed. |
a184d9bf | 84 | Optional 3rd argument TIMEZONE specifies a timezone to be represented in; |
d51c3cda RS |
85 | if nil, the local time zone is assumed." |
86 | (let ((new (timezone-fix-time date local timezone))) | |
a47a5be5 RS |
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))) | |
90 | )) | |
91 | ||
92 | \f | |
93 | ;; | |
94 | ;; Parsers and Constructors of Date and Time | |
95 | ;; | |
96 | ||
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." | |
d51c3cda RS |
100 | (let ((zone |
101 | (if (listp timezone) | |
102 | (let* ((m (timezone-zone-to-minute timezone)) | |
103 | (absm (if (< m 0) (- m) m))) | |
104 | (format "%c%02d%02d" | |
105 | (if (< m 0) ?- ?+) (/ absm 60) (% absm 60))) | |
106 | timezone))) | |
107 | (format "%02d %s %04d %s %s" | |
108 | day | |
109 | (capitalize (car (rassq month timezone-months-assoc))) | |
110 | year | |
111 | time | |
112 | zone))) | |
a47a5be5 RS |
113 | |
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" | |
d51c3cda | 117 | year month day time)) |
a47a5be5 RS |
118 | |
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)) | |
122 | ||
123 | (defun timezone-parse-date (date) | |
6b77e539 | 124 | "Parse DATE and return a vector [YEAR MONTH DAY TIME TIMEZONE]. |
ca87e960 DL |
125 | Two-digit dates are `windowed'. Those <69 have 2000 added; otherwise 1900 |
126 | is added. Three-digit dates have 1900 added. | |
127 | TIMEZONE is nil for DATEs without a zone field. | |
128 | ||
6b77e539 | 129 | Understands the following styles: |
a47a5be5 RS |
130 | (1) 14 Apr 89 03:20[:12] [GMT] |
131 | (2) Fri, 17 Mar 89 4:01[:33] [GMT] | |
132 | (3) Mon Jan 16 16:12[:37] [GMT] 1989 | |
6b77e539 | 133 | (4) 6 May 1992 1641-JST (Wednesday) |
2f9a1ee2 RS |
134 | (5) 22-AUG-1993 10:59:12.82 |
135 | (6) Thu, 11 Apr 16:17:12 91 [MET] | |
9d02faa7 | 136 | (7) Mon, 6 Jul 16:47:20 T 1992 [MET] |
43776ca0 RS |
137 | (8) 1996-06-24 21:13:12 [GMT] |
138 | (9) 1996-06-24 21:13-ZONE" | |
ac4c237c | 139 | ;; Get rid of any text properties. |
f4573839 RS |
140 | (and (stringp date) |
141 | (or (text-properties-at 0 date) | |
142 | (next-property-change 0 date)) | |
143 | (setq date (copy-sequence date)) | |
144 | (set-text-properties 0 (length date) nil date)) | |
a47a5be5 RS |
145 | (let ((date (or date "")) |
146 | (year nil) | |
147 | (month nil) | |
148 | (day nil) | |
149 | (time nil) | |
150 | (zone nil)) ;This may be nil. | |
151 | (cond ((string-match | |
bcabbf77 RS |
152 | "\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]*\\([-+a-zA-Z0-9]+\\)" date) |
153 | ;; Styles: (1) and (2) with timezone and buggy timezone | |
154 | ;; This is most common in mail and news, | |
155 | ;; so it is worth trying first. | |
156 | (setq year 3 month 2 day 1 time 4 zone 5)) | |
157 | ((string-match | |
158 | "\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]*\\'" date) | |
159 | ;; Styles: (1) and (2) without timezone | |
160 | (setq year 3 month 2 day 1 time 4 zone nil)) | |
161 | ((string-match | |
2f9a1ee2 RS |
162 | "\\([^ \t,]+\\),[ \t]+\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\(T[ \t]+\\|\\)\\([0-9]+\\)[ \t]*\\'" date) |
163 | ;; Styles: (6) and (7) without timezone | |
164 | (setq year 6 month 3 day 2 time 4 zone nil)) | |
165 | ((string-match | |
166 | "\\([^ \t,]+\\),[ \t]+\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\(T[ \t]+\\|\\)\\([0-9]+\\)[ \t]*\\([-+a-zA-Z0-9]+\\)" date) | |
167 | ;; Styles: (6) and (7) with timezone and buggy timezone | |
168 | (setq year 6 month 3 day 2 time 4 zone 7)) | |
a47a5be5 RS |
169 | ((string-match |
170 | "\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\([0-9]+\\)" date) | |
171 | ;; Styles: (3) without timezone | |
172 | (setq year 4 month 1 day 2 time 3 zone nil)) | |
173 | ((string-match | |
174 | "\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\([-+a-zA-Z0-9]+\\)[ \t]+\\([0-9]+\\)" date) | |
6b77e539 | 175 | ;; Styles: (3) with timezone |
a47a5be5 RS |
176 | (setq year 5 month 1 day 2 time 3 zone 4)) |
177 | ((string-match | |
178 | "\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+\\)[ \t]*\\([-+a-zA-Z0-9]+\\)" date) | |
179 | ;; Styles: (4) with timezone | |
180 | (setq year 3 month 2 day 1 time 4 zone 5)) | |
b20bb856 KH |
181 | ((string-match |
182 | "\\([0-9]+\\)-\\([A-Za-z]+\\)-\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9]+:[0-9]+\\)\\(\\.[0-9]+\\)?[ \t]+\\([-+a-zA-Z0-9]+\\)" date) | |
183 | ;; Styles: (5) with timezone. | |
184 | (setq year 3 month 2 day 1 time 4 zone 6)) | |
6b77e539 | 185 | ((string-match |
9dafdfe2 | 186 | "\\([0-9]+\\)-\\([A-Za-z]+\\)-\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9]+:[0-9]+\\)\\(\\.[0-9]+\\)?" date) |
6b77e539 RS |
187 | ;; Styles: (5) without timezone. |
188 | (setq year 3 month 2 day 1 time 4 zone nil)) | |
ac4c237c | 189 | ((string-match |
ca87e960 | 190 | "\\([0-9]+\\)-\\([0-9]+\\)-\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9]+:[0-9]+\\)[ \t]+\\([-+a-zA-Z0-9]+\\)" date) |
ac4c237c MB |
191 | ;; Styles: (8) with timezone. |
192 | (setq year 1 month 2 day 3 time 4 zone 5)) | |
43776ca0 | 193 | ((string-match |
ca87e960 | 194 | "\\([0-9]+\\)-\\([0-9]+\\)-\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9]+\\)[ \t]+\\([-+a-zA-Z0-9:]+\\)" date) |
43776ca0 RS |
195 | ;; Styles: (8) with timezone with a colon in it. |
196 | (setq year 1 month 2 day 3 time 4 zone 5)) | |
ac4c237c MB |
197 | ((string-match |
198 | "\\([0-9]+\\)-\\([0-9]+\\)-\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9]+:[0-9]+\\)" date) | |
199 | ;; Styles: (8) without timezone. | |
200 | (setq year 1 month 2 day 3 time 4 zone nil)) | |
a47a5be5 | 201 | ) |
64606d07 DL |
202 | (when year |
203 | (setq year (match-string year date)) | |
162100b5 | 204 | ;; Guess ambiguous years. Assume years < 69 don't predate the |
d1912872 DL |
205 | ;; Unix Epoch, so are 2000+. Three-digit years are assumed to |
206 | ;; be relative to 1900. | |
64606d07 DL |
207 | (if (< (length year) 4) |
208 | (let ((y (string-to-int year))) | |
162100b5 | 209 | (if (< y 69) |
64606d07 DL |
210 | (setq y (+ y 100))) |
211 | (setq year (int-to-string (+ 1900 y))))) | |
212 | (setq month | |
213 | (if (= (aref date (+ (match-beginning month) 2)) ?-) | |
214 | ;; Handle numeric months, spanning exactly two digits. | |
215 | (substring date | |
216 | (match-beginning month) | |
217 | (+ (match-beginning month) 2)) | |
218 | (let* ((string (substring date | |
219 | (match-beginning month) | |
220 | (+ (match-beginning month) 3))) | |
221 | (monthnum | |
222 | (cdr (assoc (upcase string) timezone-months-assoc)))) | |
223 | (if monthnum | |
224 | (int-to-string monthnum))))) | |
225 | (setq day (match-string day date)) | |
226 | (setq time (match-string time date))) | |
227 | (if zone (setq zone (match-string zone date))) | |
a47a5be5 | 228 | ;; Return a vector. |
dd713b75 | 229 | (if (and year month) |
a47a5be5 | 230 | (vector year month day time zone) |
64606d07 | 231 | (vector "0" "0" "0" "0" nil)))) |
a47a5be5 RS |
232 | |
233 | (defun timezone-parse-time (time) | |
234 | "Parse TIME (HH:MM:SS) and return a vector [hour minute second]. | |
235 | Recognize HH:MM:SS, HH:MM, HHMMSS, HHMM." | |
236 | (let ((time (or time "")) | |
64606d07 | 237 | hour minute second) |
a47a5be5 RS |
238 | (cond ((string-match "\\`\\([0-9]+\\):\\([0-9]+\\):\\([0-9]+\\)\\'" time) |
239 | ;; HH:MM:SS | |
240 | (setq hour 1 minute 2 second 3)) | |
241 | ((string-match "\\`\\([0-9]+\\):\\([0-9]+\\)\\'" time) | |
242 | ;; HH:MM | |
243 | (setq hour 1 minute 2 second nil)) | |
244 | ((string-match "\\`\\([0-9][0-9]\\)\\([0-9][0-9]\\)\\([0-9][0-9]\\)\\'" time) | |
245 | ;; HHMMSS | |
246 | (setq hour 1 minute 2 second 3)) | |
247 | ((string-match "\\`\\([0-9][0-9]\\)\\([0-9][0-9]\\)\\'" time) | |
248 | ;; HHMM | |
249 | (setq hour 1 minute 2 second nil)) | |
250 | ) | |
251 | ;; Return [hour minute second] | |
252 | (vector | |
64606d07 DL |
253 | (if hour (match-string hour time) "0") |
254 | (if minute (match-string minute time) "0") | |
255 | (if second (match-string second time) "0")))) | |
a47a5be5 RS |
256 | |
257 | \f | |
258 | ;; Miscellaneous | |
259 | ||
260 | (defun timezone-zone-to-minute (timezone) | |
d51c3cda RS |
261 | "Translate TIMEZONE to an integer minute offset from GMT. |
262 | TIMEZONE can be a cons cell containing the output of current-time-zone, | |
263 | or an integer of the form +-HHMM, or a time zone name." | |
264 | (cond | |
265 | ((consp timezone) | |
266 | (/ (car timezone) 60)) | |
267 | (timezone | |
a47a5be5 RS |
268 | (progn |
269 | (setq timezone | |
270 | (or (cdr (assoc (upcase timezone) timezone-world-timezones)) | |
271 | ;; +900 | |
272 | timezone)) | |
273 | (if (stringp timezone) | |
274 | (setq timezone (string-to-int timezone))) | |
275 | ;; Taking account of minute in timezone. | |
276 | ;; HHMM -> MM | |
9b1868cc | 277 | (let* ((abszone (abs timezone)) |
a47a5be5 | 278 | (minutes (+ (* 60 (/ abszone 100)) (% abszone 100)))) |
d51c3cda RS |
279 | (if (< timezone 0) (- minutes) minutes)))) |
280 | (t 0))) | |
281 | ||
282 | (defun timezone-time-from-absolute (date seconds) | |
283 | "Compute the UTC time equivalent to DATE at time SECONDS after midnight. | |
284 | Return a list suitable as an argument to current-time-zone, | |
285 | or nil if the date cannot be thus represented. | |
286 | DATE is the number of days elapsed since the (imaginary) | |
287 | Gregorian date Sunday, December 31, 1 BC." | |
db853edc | 288 | (let* ((current-time-origin 719163) |
d51c3cda RS |
289 | ;; (timezone-absolute-from-gregorian 1 1 1970) |
290 | (days (- date current-time-origin)) | |
291 | (seconds-per-day (float 86400)) | |
292 | (seconds (+ seconds (* days seconds-per-day))) | |
293 | (current-time-arithmetic-base (float 65536)) | |
294 | (hi (floor (/ seconds current-time-arithmetic-base))) | |
295 | (hibase (* hi current-time-arithmetic-base)) | |
296 | (lo (floor (- seconds hibase)))) | |
297 | (and (< (abs (- seconds (+ hibase lo))) 2) ;; Check for integer overflow. | |
298 | (cons hi lo)))) | |
a47a5be5 | 299 | |
d51c3cda RS |
300 | (defun timezone-time-zone-from-absolute (date seconds) |
301 | "Compute the local time zone for DATE at time SECONDS after midnight. | |
302 | Return a list in the same format as current-time-zone's result, | |
303 | or nil if the local time zone could not be computed. | |
304 | DATE is the number of days elapsed since the (imaginary) | |
305 | Gregorian date Sunday, December 31, 1 BC." | |
306 | (and (fboundp 'current-time-zone) | |
307 | (let ((utc-time (timezone-time-from-absolute date seconds))) | |
308 | (and utc-time | |
309 | (let ((zone (current-time-zone utc-time))) | |
310 | (and (car zone) zone)))))) | |
311 | ||
312 | (defun timezone-fix-time (date local timezone) | |
dce33aad | 313 | "Convert DATE (default timezone LOCAL) to YYYY-MM-DD-HH-MM-SS-ZONE vector. |
d51c3cda RS |
314 | If LOCAL is nil, it is assumed to be GMT. |
315 | If TIMEZONE is nil, use the local time zone." | |
316 | (let* ((date (timezone-parse-date date)) | |
317 | (year (string-to-int (aref date 0))) | |
d1912872 | 318 | (year (cond ((< year 69) |
13d76d1c RS |
319 | (+ year 2000)) |
320 | ((< year 100) | |
321 | (+ year 1900)) | |
d1912872 DL |
322 | ((< year 1000) ; possible 3-digit years. |
323 | (+ year 1900)) | |
13d76d1c | 324 | (t year))) |
d51c3cda RS |
325 | (month (string-to-int (aref date 1))) |
326 | (day (string-to-int (aref date 2))) | |
327 | (time (timezone-parse-time (aref date 3))) | |
328 | (hour (string-to-int (aref time 0))) | |
329 | (minute (string-to-int (aref time 1))) | |
330 | (second (string-to-int (aref time 2))) | |
331 | (local (or (aref date 4) local)) ;Use original if defined | |
332 | (timezone | |
333 | (or timezone | |
334 | (timezone-time-zone-from-absolute | |
335 | (timezone-absolute-from-gregorian month day year) | |
336 | (+ second (* 60 (+ minute (* 60 hour))))))) | |
337 | (diff (- (timezone-zone-to-minute timezone) | |
338 | (timezone-zone-to-minute local))) | |
339 | (minute (+ minute diff)) | |
9b1868cc | 340 | (hour-fix (floor minute 60))) |
a47a5be5 | 341 | (setq hour (+ hour hour-fix)) |
d51c3cda RS |
342 | (setq minute (- minute (* 60 hour-fix))) |
343 | ;; HOUR may be larger than 24 or smaller than 0. | |
344 | (cond ((<= 24 hour) ;24 -> 00 | |
345 | (setq hour (- hour 24)) | |
346 | (setq day (1+ day)) | |
ca87e960 DL |
347 | (when (< (timezone-last-day-of-month month year) day) |
348 | (setq month (1+ month)) | |
349 | (setq day 1) | |
350 | (when (< 12 month) | |
351 | (setq month 1) | |
352 | (setq year (1+ year))))) | |
d51c3cda RS |
353 | ((> 0 hour) |
354 | (setq hour (+ hour 24)) | |
355 | (setq day (1- day)) | |
ca87e960 DL |
356 | (when (> 1 day) |
357 | (setq month (1- month)) | |
358 | (when (> 1 month) | |
359 | (setq month 12) | |
360 | (setq year (1- year))) | |
361 | (setq day (timezone-last-day-of-month month year))))) | |
d51c3cda | 362 | (vector year month day hour minute second timezone))) |
a47a5be5 RS |
363 | |
364 | ;; Partly copied from Calendar program by Edward M. Reingold. | |
365 | ;; Thanks a lot. | |
366 | ||
367 | (defun timezone-last-day-of-month (month year) | |
368 | "The last day in MONTH during YEAR." | |
369 | (if (and (= month 2) (timezone-leap-year-p year)) | |
370 | 29 | |
371 | (aref [31 28 31 30 31 30 31 31 30 31 30 31] (1- month)))) | |
372 | ||
373 | (defun timezone-leap-year-p (year) | |
374 | "Returns t if YEAR is a Gregorian leap year." | |
375 | (or (and (zerop (% year 4)) | |
376 | (not (zerop (% year 100)))) | |
377 | (zerop (% year 400)))) | |
aa56d805 | 378 | |
d51c3cda RS |
379 | (defun timezone-day-number (month day year) |
380 | "Return the day number within the year of the date month/day/year." | |
381 | (let ((day-of-year (+ day (* 31 (1- month))))) | |
382 | (if (> month 2) | |
383 | (progn | |
384 | (setq day-of-year (- day-of-year (/ (+ 23 (* 4 month)) 10))) | |
385 | (if (timezone-leap-year-p year) | |
386 | (setq day-of-year (1+ day-of-year))))) | |
387 | day-of-year)) | |
388 | ||
389 | (defun timezone-absolute-from-gregorian (month day year) | |
390 | "The number of days between the Gregorian date 12/31/1 BC and month/day/year. | |
391 | The Gregorian date Sunday, December 31, 1 BC is imaginary." | |
392 | (+ (timezone-day-number month day year);; Days this year | |
393 | (* 365 (1- year));; + Days in prior years | |
394 | (/ (1- year) 4);; + Julian leap years | |
395 | (- (/ (1- year) 100));; - century years | |
396 | (/ (1- year) 400)));; + Gregorian leap years | |
397 | ||
64606d07 DL |
398 | (provide 'timezone) |
399 | ||
aa56d805 | 400 | ;;; timezone.el ends here |