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be010748 | 1 | ;;; timezone.el --- time zone package for GNU Emacs |
a47a5be5 | 2 | |
c90f2757 | 3 | ;; Copyright (C) 1990, 1991, 1992, 1993, 1996, 1999, 2001, 2002, 2003, |
409cc4a3 | 4 | ;; 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc. |
aa56d805 | 5 | |
be010748 RS |
6 | ;; Author: Masanobu Umeda |
7 | ;; Maintainer: umerin@mse.kyutech.ac.jp | |
8 | ;; Keywords: news | |
a47a5be5 RS |
9 | |
10 | ;; This file is part of GNU Emacs. | |
11 | ||
eb3fa2cf | 12 | ;; GNU Emacs is free software: you can redistribute it and/or modify |
a47a5be5 | 13 | ;; it under the terms of the GNU General Public License as published by |
eb3fa2cf GM |
14 | ;; the Free Software Foundation, either version 3 of the License, or |
15 | ;; (at your option) any later version. | |
a47a5be5 RS |
16 | |
17 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
18 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
19 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
20 | ;; GNU General Public License for more details. | |
21 | ||
22 | ;; You should have received a copy of the GNU General Public License | |
eb3fa2cf | 23 | ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. |
a47a5be5 | 24 | |
e8af40ee PJ |
25 | ;;; Commentary: |
26 | ||
a47a5be5 RS |
27 | ;;; Code: |
28 | ||
a47a5be5 RS |
29 | (defvar timezone-world-timezones |
30 | '(("PST" . -800) | |
31 | ("PDT" . -700) | |
32 | ("MST" . -700) | |
33 | ("MDT" . -600) | |
34 | ("CST" . -600) | |
35 | ("CDT" . -500) | |
36 | ("EST" . -500) | |
37 | ("EDT" . -400) | |
38 | ("AST" . -400) ;by <clamen@CS.CMU.EDU> | |
39 | ("NST" . -330) ;by <clamen@CS.CMU.EDU> | |
dbc6c26a | 40 | ("UT" . +000) |
a47a5be5 RS |
41 | ("GMT" . +000) |
42 | ("BST" . +100) | |
43 | ("MET" . +100) | |
44 | ("EET" . +200) | |
45 | ("JST" . +900) | |
46 | ("GMT+1" . +100) ("GMT+2" . +200) ("GMT+3" . +300) | |
47 | ("GMT+4" . +400) ("GMT+5" . +500) ("GMT+6" . +600) | |
48 | ("GMT+7" . +700) ("GMT+8" . +800) ("GMT+9" . +900) | |
49 | ("GMT+10" . +1000) ("GMT+11" . +1100) ("GMT+12" . +1200) ("GMT+13" . +1300) | |
50 | ("GMT-1" . -100) ("GMT-2" . -200) ("GMT-3" . -300) | |
51 | ("GMT-4" . -400) ("GMT-5" . -500) ("GMT-6" . -600) | |
52 | ("GMT-7" . -700) ("GMT-8" . -800) ("GMT-9" . -900) | |
53 | ("GMT-10" . -1000) ("GMT-11" . -1100) ("GMT-12" . -1200)) | |
d51c3cda RS |
54 | "*Time differentials of timezone from GMT in +-HHMM form. |
55 | This list is obsolescent, and is present only for backwards compatibility, | |
56 | because time zone names are ambiguous in practice. | |
57 | Use `current-time-zone' instead.") | |
a47a5be5 RS |
58 | |
59 | (defvar timezone-months-assoc | |
60 | '(("JAN" . 1)("FEB" . 2)("MAR" . 3) | |
61 | ("APR" . 4)("MAY" . 5)("JUN" . 6) | |
62 | ("JUL" . 7)("AUG" . 8)("SEP" . 9) | |
63 | ("OCT" . 10)("NOV" . 11)("DEC" . 12)) | |
64 | "Alist of first three letters of a month and its numerical representation.") | |
65 | ||
66 | (defun timezone-make-date-arpa-standard (date &optional local timezone) | |
67 | "Convert DATE to an arpanet standard date. | |
a184d9bf | 68 | Optional 2nd argument LOCAL specifies the default local timezone of the DATE; |
d51c3cda | 69 | if nil, GMT is assumed. |
a184d9bf | 70 | Optional 3rd argument TIMEZONE specifies a time zone to be represented in; |
d51c3cda RS |
71 | if nil, the local time zone is assumed." |
72 | (let ((new (timezone-fix-time date local timezone))) | |
a47a5be5 RS |
73 | (timezone-make-arpa-date (aref new 0) (aref new 1) (aref new 2) |
74 | (timezone-make-time-string | |
75 | (aref new 3) (aref new 4) (aref new 5)) | |
d51c3cda | 76 | (aref new 6)) |
a47a5be5 RS |
77 | )) |
78 | ||
79 | (defun timezone-make-date-sortable (date &optional local timezone) | |
80 | "Convert DATE to a sortable date string. | |
a184d9bf | 81 | Optional 2nd argument LOCAL specifies the default local timezone of the DATE; |
d51c3cda | 82 | if nil, GMT is assumed. |
a184d9bf | 83 | Optional 3rd argument TIMEZONE specifies a timezone to be represented in; |
d51c3cda RS |
84 | if nil, the local time zone is assumed." |
85 | (let ((new (timezone-fix-time date local timezone))) | |
a47a5be5 RS |
86 | (timezone-make-sortable-date (aref new 0) (aref new 1) (aref new 2) |
87 | (timezone-make-time-string | |
88 | (aref new 3) (aref new 4) (aref new 5))) | |
89 | )) | |
90 | ||
91 | \f | |
92 | ;; | |
93 | ;; Parsers and Constructors of Date and Time | |
94 | ;; | |
95 | ||
96 | (defun timezone-make-arpa-date (year month day time &optional timezone) | |
97 | "Make arpanet standard date string from YEAR, MONTH, DAY, and TIME. | |
98 | Optional argument TIMEZONE specifies a time zone." | |
d51c3cda RS |
99 | (let ((zone |
100 | (if (listp timezone) | |
101 | (let* ((m (timezone-zone-to-minute timezone)) | |
102 | (absm (if (< m 0) (- m) m))) | |
103 | (format "%c%02d%02d" | |
104 | (if (< m 0) ?- ?+) (/ absm 60) (% absm 60))) | |
105 | timezone))) | |
106 | (format "%02d %s %04d %s %s" | |
107 | day | |
108 | (capitalize (car (rassq month timezone-months-assoc))) | |
109 | year | |
110 | time | |
111 | zone))) | |
a47a5be5 RS |
112 | |
113 | (defun timezone-make-sortable-date (year month day time) | |
114 | "Make sortable date string from YEAR, MONTH, DAY, and TIME." | |
115 | (format "%4d%02d%02d%s" | |
d51c3cda | 116 | year month day time)) |
a47a5be5 RS |
117 | |
118 | (defun timezone-make-time-string (hour minute second) | |
119 | "Make time string from HOUR, MINUTE, and SECOND." | |
120 | (format "%02d:%02d:%02d" hour minute second)) | |
121 | ||
122 | (defun timezone-parse-date (date) | |
6b77e539 | 123 | "Parse DATE and return a vector [YEAR MONTH DAY TIME TIMEZONE]. |
ca87e960 DL |
124 | Two-digit dates are `windowed'. Those <69 have 2000 added; otherwise 1900 |
125 | is added. Three-digit dates have 1900 added. | |
126 | TIMEZONE is nil for DATEs without a zone field. | |
127 | ||
6b77e539 | 128 | Understands the following styles: |
a47a5be5 RS |
129 | (1) 14 Apr 89 03:20[:12] [GMT] |
130 | (2) Fri, 17 Mar 89 4:01[:33] [GMT] | |
131 | (3) Mon Jan 16 16:12[:37] [GMT] 1989 | |
6b77e539 | 132 | (4) 6 May 1992 1641-JST (Wednesday) |
2f9a1ee2 RS |
133 | (5) 22-AUG-1993 10:59:12.82 |
134 | (6) Thu, 11 Apr 16:17:12 91 [MET] | |
9d02faa7 | 135 | (7) Mon, 6 Jul 16:47:20 T 1992 [MET] |
43776ca0 RS |
136 | (8) 1996-06-24 21:13:12 [GMT] |
137 | (9) 1996-06-24 21:13-ZONE" | |
ac4c237c | 138 | ;; Get rid of any text properties. |
f4573839 RS |
139 | (and (stringp date) |
140 | (or (text-properties-at 0 date) | |
141 | (next-property-change 0 date)) | |
142 | (setq date (copy-sequence date)) | |
143 | (set-text-properties 0 (length date) nil date)) | |
a47a5be5 RS |
144 | (let ((date (or date "")) |
145 | (year nil) | |
146 | (month nil) | |
147 | (day nil) | |
148 | (time nil) | |
149 | (zone nil)) ;This may be nil. | |
150 | (cond ((string-match | |
f44c1370 | 151 | "\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\([-+a-zA-Z0-9]+\\)" date) |
bcabbf77 RS |
152 | ;; Styles: (1) and (2) with timezone and buggy timezone |
153 | ;; This is most common in mail and news, | |
154 | ;; so it is worth trying first. | |
155 | (setq year 3 month 2 day 1 time 4 zone 5)) | |
156 | ((string-match | |
157 | "\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]*\\'" date) | |
158 | ;; Styles: (1) and (2) without timezone | |
159 | (setq year 3 month 2 day 1 time 4 zone nil)) | |
160 | ((string-match | |
2f9a1ee2 RS |
161 | "\\([^ \t,]+\\),[ \t]+\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\(T[ \t]+\\|\\)\\([0-9]+\\)[ \t]*\\'" date) |
162 | ;; Styles: (6) and (7) without timezone | |
163 | (setq year 6 month 3 day 2 time 4 zone nil)) | |
164 | ((string-match | |
165 | "\\([^ \t,]+\\),[ \t]+\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\(T[ \t]+\\|\\)\\([0-9]+\\)[ \t]*\\([-+a-zA-Z0-9]+\\)" date) | |
166 | ;; Styles: (6) and (7) with timezone and buggy timezone | |
167 | (setq year 6 month 3 day 2 time 4 zone 7)) | |
a47a5be5 RS |
168 | ((string-match |
169 | "\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\([0-9]+\\)" date) | |
170 | ;; Styles: (3) without timezone | |
171 | (setq year 4 month 1 day 2 time 3 zone nil)) | |
172 | ((string-match | |
173 | "\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\([-+a-zA-Z0-9]+\\)[ \t]+\\([0-9]+\\)" date) | |
6b77e539 | 174 | ;; Styles: (3) with timezone |
a47a5be5 RS |
175 | (setq year 5 month 1 day 2 time 3 zone 4)) |
176 | ((string-match | |
177 | "\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+\\)[ \t]*\\([-+a-zA-Z0-9]+\\)" date) | |
178 | ;; Styles: (4) with timezone | |
179 | (setq year 3 month 2 day 1 time 4 zone 5)) | |
b20bb856 KH |
180 | ((string-match |
181 | "\\([0-9]+\\)-\\([A-Za-z]+\\)-\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9]+:[0-9]+\\)\\(\\.[0-9]+\\)?[ \t]+\\([-+a-zA-Z0-9]+\\)" date) | |
182 | ;; Styles: (5) with timezone. | |
183 | (setq year 3 month 2 day 1 time 4 zone 6)) | |
6b77e539 | 184 | ((string-match |
9dafdfe2 | 185 | "\\([0-9]+\\)-\\([A-Za-z]+\\)-\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9]+:[0-9]+\\)\\(\\.[0-9]+\\)?" date) |
6b77e539 RS |
186 | ;; Styles: (5) without timezone. |
187 | (setq year 3 month 2 day 1 time 4 zone nil)) | |
ac4c237c | 188 | ((string-match |
ca87e960 | 189 | "\\([0-9]+\\)-\\([0-9]+\\)-\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9]+:[0-9]+\\)[ \t]+\\([-+a-zA-Z0-9]+\\)" date) |
ac4c237c MB |
190 | ;; Styles: (8) with timezone. |
191 | (setq year 1 month 2 day 3 time 4 zone 5)) | |
43776ca0 | 192 | ((string-match |
a996695f | 193 | "\\([0-9]+\\)-\\([0-9]+\\)-\\([0-9]+\\)[T \t]+\\([0-9]+:[0-9]+\\)[ \t]+\\([-+a-zA-Z0-9:]+\\)" date) |
43776ca0 RS |
194 | ;; Styles: (8) with timezone with a colon in it. |
195 | (setq year 1 month 2 day 3 time 4 zone 5)) | |
ac4c237c | 196 | ((string-match |
a996695f | 197 | "\\([0-9]+\\)-\\([0-9]+\\)-\\([0-9]+\\)[T \t]+\\([0-9]+:[0-9]+:[0-9]+\\)" date) |
ac4c237c MB |
198 | ;; Styles: (8) without timezone. |
199 | (setq year 1 month 2 day 3 time 4 zone nil)) | |
a47a5be5 | 200 | ) |
64606d07 DL |
201 | (when year |
202 | (setq year (match-string year date)) | |
162100b5 | 203 | ;; Guess ambiguous years. Assume years < 69 don't predate the |
d1912872 DL |
204 | ;; Unix Epoch, so are 2000+. Three-digit years are assumed to |
205 | ;; be relative to 1900. | |
64606d07 | 206 | (if (< (length year) 4) |
027a4b6b | 207 | (let ((y (string-to-number year))) |
162100b5 | 208 | (if (< y 69) |
64606d07 DL |
209 | (setq y (+ y 100))) |
210 | (setq year (int-to-string (+ 1900 y))))) | |
211 | (setq month | |
212 | (if (= (aref date (+ (match-beginning month) 2)) ?-) | |
213 | ;; Handle numeric months, spanning exactly two digits. | |
214 | (substring date | |
215 | (match-beginning month) | |
216 | (+ (match-beginning month) 2)) | |
217 | (let* ((string (substring date | |
218 | (match-beginning month) | |
219 | (+ (match-beginning month) 3))) | |
220 | (monthnum | |
221 | (cdr (assoc (upcase string) timezone-months-assoc)))) | |
222 | (if monthnum | |
223 | (int-to-string monthnum))))) | |
224 | (setq day (match-string day date)) | |
225 | (setq time (match-string time date))) | |
226 | (if zone (setq zone (match-string zone date))) | |
a47a5be5 | 227 | ;; Return a vector. |
dd713b75 | 228 | (if (and year month) |
a47a5be5 | 229 | (vector year month day time zone) |
64606d07 | 230 | (vector "0" "0" "0" "0" nil)))) |
a47a5be5 RS |
231 | |
232 | (defun timezone-parse-time (time) | |
233 | "Parse TIME (HH:MM:SS) and return a vector [hour minute second]. | |
234 | Recognize HH:MM:SS, HH:MM, HHMMSS, HHMM." | |
235 | (let ((time (or time "")) | |
64606d07 | 236 | hour minute second) |
a47a5be5 RS |
237 | (cond ((string-match "\\`\\([0-9]+\\):\\([0-9]+\\):\\([0-9]+\\)\\'" time) |
238 | ;; HH:MM:SS | |
239 | (setq hour 1 minute 2 second 3)) | |
240 | ((string-match "\\`\\([0-9]+\\):\\([0-9]+\\)\\'" time) | |
241 | ;; HH:MM | |
242 | (setq hour 1 minute 2 second nil)) | |
243 | ((string-match "\\`\\([0-9][0-9]\\)\\([0-9][0-9]\\)\\([0-9][0-9]\\)\\'" time) | |
244 | ;; HHMMSS | |
245 | (setq hour 1 minute 2 second 3)) | |
246 | ((string-match "\\`\\([0-9][0-9]\\)\\([0-9][0-9]\\)\\'" time) | |
247 | ;; HHMM | |
248 | (setq hour 1 minute 2 second nil)) | |
249 | ) | |
250 | ;; Return [hour minute second] | |
251 | (vector | |
64606d07 DL |
252 | (if hour (match-string hour time) "0") |
253 | (if minute (match-string minute time) "0") | |
254 | (if second (match-string second time) "0")))) | |
a47a5be5 RS |
255 | |
256 | \f | |
257 | ;; Miscellaneous | |
258 | ||
259 | (defun timezone-zone-to-minute (timezone) | |
d51c3cda RS |
260 | "Translate TIMEZONE to an integer minute offset from GMT. |
261 | TIMEZONE can be a cons cell containing the output of current-time-zone, | |
262 | or an integer of the form +-HHMM, or a time zone name." | |
263 | (cond | |
264 | ((consp timezone) | |
265 | (/ (car timezone) 60)) | |
266 | (timezone | |
a47a5be5 RS |
267 | (progn |
268 | (setq timezone | |
269 | (or (cdr (assoc (upcase timezone) timezone-world-timezones)) | |
270 | ;; +900 | |
271 | timezone)) | |
272 | (if (stringp timezone) | |
027a4b6b | 273 | (setq timezone (string-to-number timezone))) |
a47a5be5 RS |
274 | ;; Taking account of minute in timezone. |
275 | ;; HHMM -> MM | |
9b1868cc | 276 | (let* ((abszone (abs timezone)) |
a47a5be5 | 277 | (minutes (+ (* 60 (/ abszone 100)) (% abszone 100)))) |
d51c3cda RS |
278 | (if (< timezone 0) (- minutes) minutes)))) |
279 | (t 0))) | |
280 | ||
281 | (defun timezone-time-from-absolute (date seconds) | |
282 | "Compute the UTC time equivalent to DATE at time SECONDS after midnight. | |
283 | Return a list suitable as an argument to current-time-zone, | |
284 | or nil if the date cannot be thus represented. | |
285 | DATE is the number of days elapsed since the (imaginary) | |
286 | Gregorian date Sunday, December 31, 1 BC." | |
db853edc | 287 | (let* ((current-time-origin 719163) |
d51c3cda RS |
288 | ;; (timezone-absolute-from-gregorian 1 1 1970) |
289 | (days (- date current-time-origin)) | |
290 | (seconds-per-day (float 86400)) | |
291 | (seconds (+ seconds (* days seconds-per-day))) | |
292 | (current-time-arithmetic-base (float 65536)) | |
293 | (hi (floor (/ seconds current-time-arithmetic-base))) | |
294 | (hibase (* hi current-time-arithmetic-base)) | |
295 | (lo (floor (- seconds hibase)))) | |
296 | (and (< (abs (- seconds (+ hibase lo))) 2) ;; Check for integer overflow. | |
297 | (cons hi lo)))) | |
a47a5be5 | 298 | |
d51c3cda RS |
299 | (defun timezone-time-zone-from-absolute (date seconds) |
300 | "Compute the local time zone for DATE at time SECONDS after midnight. | |
301 | Return a list in the same format as current-time-zone's result, | |
302 | or nil if the local time zone could not be computed. | |
303 | DATE is the number of days elapsed since the (imaginary) | |
304 | Gregorian date Sunday, December 31, 1 BC." | |
305 | (and (fboundp 'current-time-zone) | |
306 | (let ((utc-time (timezone-time-from-absolute date seconds))) | |
307 | (and utc-time | |
308 | (let ((zone (current-time-zone utc-time))) | |
309 | (and (car zone) zone)))))) | |
310 | ||
311 | (defun timezone-fix-time (date local timezone) | |
dce33aad | 312 | "Convert DATE (default timezone LOCAL) to YYYY-MM-DD-HH-MM-SS-ZONE vector. |
d51c3cda RS |
313 | If LOCAL is nil, it is assumed to be GMT. |
314 | If TIMEZONE is nil, use the local time zone." | |
315 | (let* ((date (timezone-parse-date date)) | |
027a4b6b | 316 | (year (string-to-number (aref date 0))) |
d1912872 | 317 | (year (cond ((< year 69) |
13d76d1c RS |
318 | (+ year 2000)) |
319 | ((< year 100) | |
320 | (+ year 1900)) | |
d1912872 DL |
321 | ((< year 1000) ; possible 3-digit years. |
322 | (+ year 1900)) | |
13d76d1c | 323 | (t year))) |
027a4b6b JB |
324 | (month (string-to-number (aref date 1))) |
325 | (day (string-to-number (aref date 2))) | |
d51c3cda | 326 | (time (timezone-parse-time (aref date 3))) |
027a4b6b JB |
327 | (hour (string-to-number (aref time 0))) |
328 | (minute (string-to-number (aref time 1))) | |
329 | (second (string-to-number (aref time 2))) | |
d51c3cda RS |
330 | (local (or (aref date 4) local)) ;Use original if defined |
331 | (timezone | |
332 | (or timezone | |
333 | (timezone-time-zone-from-absolute | |
334 | (timezone-absolute-from-gregorian month day year) | |
335 | (+ second (* 60 (+ minute (* 60 hour))))))) | |
336 | (diff (- (timezone-zone-to-minute timezone) | |
337 | (timezone-zone-to-minute local))) | |
338 | (minute (+ minute diff)) | |
9b1868cc | 339 | (hour-fix (floor minute 60))) |
a47a5be5 | 340 | (setq hour (+ hour hour-fix)) |
d51c3cda RS |
341 | (setq minute (- minute (* 60 hour-fix))) |
342 | ;; HOUR may be larger than 24 or smaller than 0. | |
343 | (cond ((<= 24 hour) ;24 -> 00 | |
344 | (setq hour (- hour 24)) | |
345 | (setq day (1+ day)) | |
ca87e960 DL |
346 | (when (< (timezone-last-day-of-month month year) day) |
347 | (setq month (1+ month)) | |
348 | (setq day 1) | |
349 | (when (< 12 month) | |
350 | (setq month 1) | |
351 | (setq year (1+ year))))) | |
d51c3cda RS |
352 | ((> 0 hour) |
353 | (setq hour (+ hour 24)) | |
354 | (setq day (1- day)) | |
ca87e960 DL |
355 | (when (> 1 day) |
356 | (setq month (1- month)) | |
357 | (when (> 1 month) | |
358 | (setq month 12) | |
359 | (setq year (1- year))) | |
360 | (setq day (timezone-last-day-of-month month year))))) | |
d51c3cda | 361 | (vector year month day hour minute second timezone))) |
a47a5be5 RS |
362 | |
363 | ;; Partly copied from Calendar program by Edward M. Reingold. | |
364 | ;; Thanks a lot. | |
365 | ||
366 | (defun timezone-last-day-of-month (month year) | |
367 | "The last day in MONTH during YEAR." | |
368 | (if (and (= month 2) (timezone-leap-year-p year)) | |
369 | 29 | |
370 | (aref [31 28 31 30 31 30 31 31 30 31 30 31] (1- month)))) | |
371 | ||
372 | (defun timezone-leap-year-p (year) | |
373 | "Returns t if YEAR is a Gregorian leap year." | |
374 | (or (and (zerop (% year 4)) | |
375 | (not (zerop (% year 100)))) | |
376 | (zerop (% year 400)))) | |
aa56d805 | 377 | |
d51c3cda RS |
378 | (defun timezone-day-number (month day year) |
379 | "Return the day number within the year of the date month/day/year." | |
380 | (let ((day-of-year (+ day (* 31 (1- month))))) | |
381 | (if (> month 2) | |
382 | (progn | |
383 | (setq day-of-year (- day-of-year (/ (+ 23 (* 4 month)) 10))) | |
384 | (if (timezone-leap-year-p year) | |
385 | (setq day-of-year (1+ day-of-year))))) | |
386 | day-of-year)) | |
387 | ||
388 | (defun timezone-absolute-from-gregorian (month day year) | |
389 | "The number of days between the Gregorian date 12/31/1 BC and month/day/year. | |
390 | The Gregorian date Sunday, December 31, 1 BC is imaginary." | |
391 | (+ (timezone-day-number month day year);; Days this year | |
392 | (* 365 (1- year));; + Days in prior years | |
393 | (/ (1- year) 4);; + Julian leap years | |
394 | (- (/ (1- year) 100));; - century years | |
395 | (/ (1- year) 400)));; + Gregorian leap years | |
396 | ||
64606d07 DL |
397 | (provide 'timezone) |
398 | ||
cbee283d | 399 | ;; arch-tag: e23d5bc6-f32d-48ba-8996-323e9d654b3f |
aa56d805 | 400 | ;;; timezone.el ends here |