-;;; cal-dst.el --- calendar functions for daylight savings rules.
+;;; cal-dst.el --- calendar functions for daylight savings rules
-;; Copyright (C) 1993, 1994, 1995 Free Software Foundation, Inc.
+;; Copyright (C) 1993, 1994, 1995, 1996, 2001, 2002, 2003, 2004, 2005,
+;; 2006 Free Software Foundation, Inc.
;; Author: Paul Eggert <eggert@twinsun.com>
;; Edward M. Reingold <reingold@cs.uiuc.edu>
+;; Maintainer: Glenn Morris <rgm@gnu.org>
;; Keywords: calendar
;; Human-Keywords: daylight savings time, calendar, diary, holidays
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
-;; along with GNU Emacs; see the file COPYING. If not, write to
-;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+;; along with GNU Emacs; see the file COPYING. If not, write to the
+;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+;; Boston, MA 02110-1301, USA.
;;; Commentary:
;;; Code:
(require 'calendar)
+(require 'cal-persia)
(defvar calendar-current-time-zone-cache nil
"Cache for result of calendar-current-time-zone.")
(defun calendar-time-from-absolute (abs-date s)
"Time of absolute date ABS-DATE, S seconds after midnight.
-Returns the pair (HIGH . LOW) where HIGH and LOW are the high and low
+Returns the list (HIGH LOW) where HIGH and LOW are the high and low
16 bits, respectively, of the number of seconds 1970-01-01 00:00:00 UTC,
ignoring leap seconds, that is the equivalent moment to S seconds after
midnight UTC on absolute date ABS-DATE."
(let* ((a (- abs-date calendar-system-time-basis))
(u (+ (* 163 (mod a 512)) (floor s 128))))
;; Overflow is a terrible thing!
- (cons
+ (list
;; floor((60*60*24*a + s) / 2^16)
(+ a (* 163 (floor a 512)) (floor u 512))
;; (60*60*24*a + s) mod 2^16
(defun calendar-time-zone-daylight-rules (abs-date utc-diff)
"Return daylight transition rule for ABS-DATE, UTC-DIFF sec offset from UTC.
-ABS-DIFF must specify a day that contains a daylight savings transition.
+ABS-DATE must specify a day that contains a daylight savings transition.
The result has the proper form for calendar-daylight-savings-starts'."
(let* ((date (calendar-gregorian-from-absolute abs-date))
(weekday (% abs-date 7))
(cons
(list 'calendar-nth-named-day 1 weekday m 'year j)
l)))
- l)))
+ l)
+ ;; 01-01 and 07-01 for this year's Persian calendar.
+ (if (and (= m 3) (<= 20 d) (<= d 21))
+ '((calendar-gregorian-from-absolute
+ (calendar-absolute-from-persian
+ (list 1 1 (- year 621))))))
+ (if (and (= m 9) (<= 22 d) (<= d 23))
+ '((calendar-gregorian-from-absolute
+ (calendar-absolute-from-persian
+ (list 7 1 (- year 621))))))))
(prevday-sec (- -1 utc-diff)) ;; last sec of previous local day
(year (1+ y)))
;; Scan through the next few years until only one rule remains.
(defvar calendar-daylight-time-offset
(or (car (cdr calendar-current-time-zone-cache)) 60)
"*Number of minutes difference between daylight savings and standard time.
-
+
If the locale never uses daylight savings time, set this to 0.")
(defvar calendar-standard-time-zone-name
(or (car (nthcdr 3 calendar-current-time-zone-cache)) "EDT")
"*Abbreviated name of daylight-savings time zone at `calendar-location-name'.
For example, \"EDT\" in New York City, \"PDT\" for Los Angeles.")
-
+
;;;###autoload
(put 'calendar-daylight-savings-starts 'risky-local-variable t)
(defvar calendar-daylight-savings-starts
'(calendar-nth-named-day -1 0 10 year)
If the locale never uses daylight savings time, set this to nil.")
-
+
(defvar calendar-daylight-savings-starts-time
(or (car (nthcdr 6 calendar-current-time-zone-cache)) 120)
"*Number of minutes after midnight that daylight savings time starts.")
-
+
(defvar calendar-daylight-savings-ends-time
(or (car (nthcdr 7 calendar-current-time-zone-cache))
calendar-daylight-savings-starts-time)
(defun dst-in-effect (date)
"True if on absolute DATE daylight savings time is in effect.
-Fractional part of DATE is time of day."
+Fractional part of DATE is local standard time of day."
(let* ((year (extract-calendar-year
(calendar-gregorian-from-absolute (floor date))))
- (dst-starts (and (eval calendar-daylight-savings-starts)
+ (dst-starts-gregorian (eval calendar-daylight-savings-starts))
+ (dst-ends-gregorian (eval calendar-daylight-savings-ends))
+ (dst-starts (and dst-starts-gregorian
(+ (calendar-absolute-from-gregorian
- (eval calendar-daylight-savings-starts))
+ dst-starts-gregorian)
(/ calendar-daylight-savings-starts-time
60.0 24.0))))
- (dst-ends (and (eval calendar-daylight-savings-ends)
+ (dst-ends (and dst-ends-gregorian
(+ (calendar-absolute-from-gregorian
- (eval calendar-daylight-savings-ends))
+ dst-ends-gregorian)
(/ (- calendar-daylight-savings-ends-time
calendar-daylight-time-offset)
60.0 24.0)))))
- (and (and dst-starts dst-ends
- (or (and (< dst-starts dst-ends);; northern hemi.
- (<= dst-starts date) (< date dst-ends))
- (and (< dst-ends dst-starts);; southern hemi.
- (<= dst-starts date) (< date dst-ends))
- (and dst-starts (not dst-ends) (<= dst-starts date))
- (and dst-ends (not dst-starts) (< date dst-ends)))))))
+ (and dst-starts dst-ends
+ (if (< dst-starts dst-ends)
+ (and (<= dst-starts date) (< date dst-ends))
+ (or (<= dst-starts date) (< date dst-ends))))))
(defun dst-adjust-time (date time &optional style)
"Adjust, to account for dst on DATE, decimal fraction standard TIME.
(provide 'cal-dst)
+;;; arch-tag: a141d204-213c-4ca5-bdc6-f9df3aa92aad
;;; cal-dst.el ends here