--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lisp/utils/timezone.el	Mon Aug 13 08:45:50 2007 +0200
@@ -0,0 +1,406 @@
+;;; timezone.el --- time zone package for GNU Emacs
+
+;; Copyright (C) 1990, 1991, 1992, 1993 Free Software Foundation, Inc.
+
+;; Author: Masanobu Umeda
+;; Maintainer: umerin@mse.kyutech.ac.jp
+;; Keywords: news
+
+;; This file is part of XEmacs.
+
+;; XEmacs is free software; you can redistribute it and/or modify it
+;; under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 2, or (at your option)
+;; any later version.
+
+;; XEmacs is distributed in the hope that it will be useful, but
+;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+;; General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with XEmacs; see the file COPYING.  If not, write to the Free
+;; Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+
+;;; Synched up with: FSF 19.30.
+
+;; Modified 1 February 1994 by Kyle Jones to fix broken
+;; timezone-floor function.
+
+;; Modified 25 January 1994 by Kyle Jones so that it will
+;; work under version 18 of Emacs.  Provided timezone-floor
+;; and timezone-abs functions.
+
+;;; Code:
+
+(provide 'timezone)
+
+(defvar timezone-world-timezones
+  '(("PST" .  -800)
+    ("PDT" .  -700)
+    ("MST" .  -700)
+    ("MDT" .  -600)
+    ("CST" .  -600)
+    ("CDT" .  -500)
+    ("EST" .  -500)
+    ("EDT" .  -400)
+    ("AST" .  -400)			;by <clamen@CS.CMU.EDU>
+    ("NST" .  -330)			;by <clamen@CS.CMU.EDU>
+    ("UT"  .  +000)
+    ("GMT" .  +000)
+    ("BST" .  +100)
+    ("MET" .  +100)
+    ("EET" .  +200)
+    ("JST" .  +900)
+    ("GMT+1"  .  +100) ("GMT+2"  .  +200) ("GMT+3"  .  +300)
+    ("GMT+4"  .  +400) ("GMT+5"  .  +500) ("GMT+6"  .  +600)
+    ("GMT+7"  .  +700) ("GMT+8"  .  +800) ("GMT+9"  .  +900)
+    ("GMT+10" . +1000) ("GMT+11" . +1100) ("GMT+12" . +1200) ("GMT+13" . +1300)
+    ("GMT-1"  .  -100) ("GMT-2"  .  -200) ("GMT-3"  .  -300)
+    ("GMT-4"  .  -400) ("GMT-5"  .  -500) ("GMT-6"  .  -600)
+    ("GMT-7"  .  -700) ("GMT-8"  .  -800) ("GMT-9"  .  -900)
+    ("GMT-10" . -1000) ("GMT-11" . -1100) ("GMT-12" . -1200))
+  "*Time differentials of timezone from GMT in +-HHMM form.
+This list is obsolescent, and is present only for backwards compatibility,
+because time zone names are ambiguous in practice.
+Use `current-time-zone' instead.")
+
+(defvar timezone-months-assoc
+  '(("JAN" .  1)("FEB" .  2)("MAR" .  3)
+    ("APR" .  4)("MAY" .  5)("JUN" .  6)
+    ("JUL" .  7)("AUG" .  8)("SEP" .  9)
+    ("OCT" . 10)("NOV" . 11)("DEC" . 12))
+  "Alist of first three letters of a month and its numerical representation.")
+
+(defun timezone-make-date-arpa-standard (date &optional local timezone)
+  "Convert DATE to an arpanet standard date.
+Optional 1st argument LOCAL specifies the default local timezone of the DATE;
+if nil, GMT is assumed.
+Optional 2nd argument TIMEZONE specifies a time zone to be represented in;
+if nil, the local time zone is assumed."
+  (let ((new (timezone-fix-time date local timezone)))
+    (timezone-make-arpa-date (aref new 0) (aref new 1) (aref new 2)
+			     (timezone-make-time-string
+			      (aref new 3) (aref new 4) (aref new 5))
+			     (aref new 6))
+    ))
+
+(defun timezone-make-date-sortable (date &optional local timezone)
+  "Convert DATE to a sortable date string.
+Optional 1st argument LOCAL specifies the default local timezone of the DATE;
+if nil, GMT is assumed.
+Optional 2nd argument TIMEZONE specifies a timezone to be represented in;
+if nil, the local time zone is assumed."
+  (let ((new (timezone-fix-time date local timezone)))
+    (timezone-make-sortable-date (aref new 0) (aref new 1) (aref new 2)
+				 (timezone-make-time-string
+				  (aref new 3) (aref new 4) (aref new 5)))
+    ))
+
+
+;;
+;; Parsers and Constructors of Date and Time
+;;
+
+(defun timezone-make-arpa-date (year month day time &optional timezone)
+  "Make arpanet standard date string from YEAR, MONTH, DAY, and TIME.
+Optional argument TIMEZONE specifies a time zone."
+  (let ((zone
+	 (if (listp timezone)
+	     (let* ((m (timezone-zone-to-minute timezone))
+		    (absm (if (< m 0) (- m) m)))
+	       (format "%c%02d%02d"
+		       (if (< m 0) ?- ?+) (/ absm 60) (% absm 60)))
+	   timezone)))
+    (format "%02d %s %04d %s %s"
+	    day
+	    (capitalize (car (rassq month timezone-months-assoc)))
+	    year
+	    time
+	    zone)))
+
+(defun timezone-make-sortable-date (year month day time)
+  "Make sortable date string from YEAR, MONTH, DAY, and TIME."
+  (format "%4d%02d%02d%s"
+	  year month day time))
+
+(defun timezone-make-time-string (hour minute second)
+  "Make time string from HOUR, MINUTE, and SECOND."
+  (format "%02d:%02d:%02d" hour minute second))
+
+(defun timezone-parse-date (date)
+  "Parse DATE and return a vector [YEAR MONTH DAY TIME TIMEZONE].
+19 is prepended to year if necessary.  Timezone may be nil if nothing.
+Understands the following styles:
+ (1) 14 Apr 89 03:20[:12] [GMT]
+ (2) Fri, 17 Mar 89 4:01[:33] [GMT]
+ (3) Mon Jan 16 16:12[:37] [GMT] 1989
+ (4) 6 May 1992 1641-JST (Wednesday)
+ (5) 22-AUG-1993 10:59:12.82
+ (6) Thu, 11 Apr 16:17:12 91 [MET]
+ (7) Mon, 6  Jul 16:47:20 T 1992 [MET]"
+  ;; Get rid of any text properties.
+  (and (stringp date)
+       (or (text-properties-at 0 date)
+	   (next-property-change 0 date))
+       (setq date (copy-sequence date))
+       (set-text-properties 0 (length date) nil date))
+  (let ((date (or date ""))
+	(year nil)
+	(month nil)
+	(day nil)
+	(time nil)
+	(zone nil))			;This may be nil.
+    (cond ((string-match
+	    "\\([^ \t,]+\\),[ \t]+\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\(T[ \t]+\\|\\)\\([0-9]+\\)[ \t]*\\'" date)
+	   ;; Styles: (6) and (7) without timezone
+	   (setq year 6 month 3 day 2 time 4 zone nil))
+	  ((string-match
+	    "\\([^ \t,]+\\),[ \t]+\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\(T[ \t]+\\|\\)\\([0-9]+\\)[ \t]*\\([-+a-zA-Z0-9]+\\)" date)
+	   ;; Styles: (6) and (7) with timezone and buggy timezone
+	   (setq year 6 month 3 day 2 time 4 zone 7))
+	  ((string-match
+	    "\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]*\\'" date)
+	   ;; Styles: (1) and (2) without timezone
+	   (setq year 3 month 2 day 1 time 4 zone nil))
+	  ((string-match
+	    "\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]*\\([-+a-zA-Z0-9]+\\)" date)
+	   ;; Styles: (1) and (2) with timezone and buggy timezone
+	   (setq year 3 month 2 day 1 time 4 zone 5))
+	  ((string-match
+	    "\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\([0-9]+\\)" date)
+	   ;; Styles: (3) without timezone
+	   (setq year 4 month 1 day 2 time 3 zone nil))
+	  ((string-match
+	    "\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\([-+a-zA-Z0-9]+\\)[ \t]+\\([0-9]+\\)" date)
+	   ;; Styles: (3) with timezone
+	   (setq year 5 month 1 day 2 time 3 zone 4))
+	  ((string-match
+	    "\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+\\)[ \t]*\\([-+a-zA-Z0-9]+\\)" date)
+	   ;; Styles: (4) with timezone
+	   (setq year 3 month 2 day 1 time 4 zone 5))
+	  ((string-match
+	    "\\([0-9]+\\)-\\([A-Za-z]+\\)-\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9]+:[0-9]+\\)\\.[0-9]+" date)
+	   ;; Styles: (5) without timezone.
+	   (setq year 3 month 2 day 1 time 4 zone nil))
+	  )
+    (if year
+	(progn
+	  (setq year
+		(substring date (match-beginning year) (match-end year)))
+	  ;; It is now Dec 1992.  8 years before the end of the World.
+	  (if (< (length year) 4)
+	      (setq year (concat "19" (substring year -2 nil))))
+	  (let ((string (substring date
+				   (match-beginning month)
+				   (+ (match-beginning month) 3))))
+	    (setq month
+		  (int-to-string
+		   (cdr (assoc (upcase string) timezone-months-assoc)))))
+
+	  (setq day
+		(substring date (match-beginning day) (match-end day)))
+	  (setq time
+		(substring date (match-beginning time) (match-end time)))))
+    (if zone
+	(setq zone
+	      (substring date (match-beginning zone) (match-end zone))))
+    ;; Return a vector.
+    (if year
+	(vector year month day time zone)
+      (vector "0" "0" "0" "0" nil))
+    ))
+
+(defun timezone-parse-time (time)
+  "Parse TIME (HH:MM:SS) and return a vector [hour minute second].
+Recognize HH:MM:SS, HH:MM, HHMMSS, HHMM."
+  (let ((time (or time ""))
+	(hour nil)
+	(minute nil)
+	(second nil))
+    (cond ((string-match "\\`\\([0-9]+\\):\\([0-9]+\\):\\([0-9]+\\)\\'" time)
+	   ;; HH:MM:SS
+	   (setq hour 1 minute 2 second 3))
+	  ((string-match "\\`\\([0-9]+\\):\\([0-9]+\\)\\'" time)
+	   ;; HH:MM
+	   (setq hour 1 minute 2 second nil))
+	  ((string-match "\\`\\([0-9][0-9]\\)\\([0-9][0-9]\\)\\([0-9][0-9]\\)\\'" time)
+	   ;; HHMMSS
+	   (setq hour 1 minute 2 second 3))
+	  ((string-match "\\`\\([0-9][0-9]\\)\\([0-9][0-9]\\)\\'" time)
+	   ;; HHMM
+	   (setq hour 1 minute 2 second nil))
+	  )
+    ;; Return [hour minute second]
+    (vector
+     (if hour
+	 (substring time (match-beginning hour) (match-end hour)) "0")
+     (if minute
+	 (substring time (match-beginning minute) (match-end minute)) "0")
+     (if second
+	 (substring time (match-beginning second) (match-end second)) "0"))
+    ))
+
+
+;; Miscellaneous
+
+(defun timezone-zone-to-minute (timezone)
+  "Translate TIMEZONE to an integer minute offset from GMT.
+TIMEZONE can be a cons cell containing the output of current-time-zone,
+or an integer of the form +-HHMM, or a time zone name."
+  (cond
+     ((consp timezone)
+      (/ (car timezone) 60))
+     (timezone
+      (progn
+	(setq timezone
+	      (or (cdr (assoc (upcase timezone) timezone-world-timezones))
+		  ;; +900
+		  timezone))
+	(if (stringp timezone)
+	    (setq timezone (string-to-int timezone)))
+	;; Taking account of minute in timezone.
+	;; HHMM -> MM
+	(let* ((abszone (timezone-abs timezone))
+ 	       (minutes (+ (* 60 (/ abszone 100)) (% abszone 100))))
+ 	  (if (< timezone 0) (- minutes) minutes))))
+     (t 0)))
+
+(defun timezone-time-from-absolute (date seconds)
+  "Compute the UTC time equivalent to DATE at time SECONDS after midnight.
+Return a list suitable as an argument to current-time-zone,
+or nil if the date cannot be thus represented.
+DATE is the number of days elapsed since the (imaginary)
+Gregorian date Sunday, December 31, 1 BC."
+  (let* ((current-time-origin 719162)
+	    ;; (timezone-absolute-from-gregorian 1 1 1970)
+	 (days (- date current-time-origin))
+	 (seconds-per-day (float 86400))
+	 (seconds (+ seconds (* days seconds-per-day)))
+	 (current-time-arithmetic-base (float 65536))
+	 (hi (timezone-floor (/ seconds current-time-arithmetic-base)))
+	 (hibase (* hi current-time-arithmetic-base))
+	 (lo (timezone-floor (- seconds hibase))))
+     (and (< (timezone-abs (- seconds (+ hibase lo))) 2) ;; Check for integer overflow.
+	  (cons hi lo))))
+
+(defun timezone-time-zone-from-absolute (date seconds)
+  "Compute the local time zone for DATE at time SECONDS after midnight.
+Return a list in the same format as current-time-zone's result,
+or nil if the local time zone could not be computed.
+DATE is the number of days elapsed since the (imaginary)
+Gregorian date Sunday, December 31, 1 BC."
+   (and (fboundp 'current-time-zone)
+	(let ((utc-time (timezone-time-from-absolute date seconds)))
+	  (and utc-time
+	       (let ((zone (current-time-zone utc-time)))
+		 (and (car zone) zone))))))
+
+(defun timezone-fix-time (date local timezone)
+  "Convert DATE (default timezone LOCAL) to YYYY-MM-DD-HH-MM-SS-ZONE vector.
+If LOCAL is nil, it is assumed to be GMT.
+If TIMEZONE is nil, use the local time zone."
+  (let* ((date   (timezone-parse-date date))
+	 (year   (string-to-int (aref date 0)))
+	 (year	 (cond ((< year 50)
+			(+ year 2000))
+		       ((< year 100)
+			(+ year 1900))
+		       (t year)))
+	 (month  (string-to-int (aref date 1)))
+	 (day    (string-to-int (aref date 2)))
+	 (time   (timezone-parse-time (aref date 3)))
+	 (hour   (string-to-int (aref time 0)))
+	 (minute (string-to-int (aref time 1)))
+	 (second (string-to-int (aref time 2)))
+	 (local  (or (aref date 4) local)) ;Use original if defined
+	 (timezone
+	  (or timezone
+	      (timezone-time-zone-from-absolute
+	       (timezone-absolute-from-gregorian month day year)
+	       (+ second (* 60 (+ minute (* 60 hour)))))))
+	 (diff   (- (timezone-zone-to-minute timezone)
+		    (timezone-zone-to-minute local)))
+	 (minute (+ minute diff))
+	 (hour-fix (timezone-floor minute 60)))
+    (setq hour (+ hour hour-fix))
+    (setq minute (- minute (* 60 hour-fix)))
+    ;; HOUR may be larger than 24 or smaller than 0.
+    (cond ((<= 24 hour)			;24 -> 00
+	   (setq hour (- hour 24))
+	   (setq day  (1+ day))
+	   (if (< (timezone-last-day-of-month month year) day)
+	       (progn
+		 (setq month (1+ month))
+		 (setq day 1)
+		 (if (< 12 month)
+		     (progn
+		       (setq month 1)
+		       (setq year (1+ year))
+		       ))
+		 )))
+	  ((> 0 hour)
+	   (setq hour (+ hour 24))
+	   (setq day  (1- day))
+	   (if (> 1 day)
+	       (progn
+		 (setq month (1- month))
+		 (if (> 1 month)
+		     (progn
+		       (setq month 12)
+		       (setq year (1- year))
+		       ))
+		 (setq day (timezone-last-day-of-month month year))
+		 )))
+	  )
+    (vector year month day hour minute second timezone)))
+
+;; Partly copied from Calendar program by Edward M. Reingold.
+;; Thanks a lot.
+
+(defun timezone-last-day-of-month (month year)
+  "The last day in MONTH during YEAR."
+  (if (and (= month 2) (timezone-leap-year-p year))
+      29
+    (aref [31 28 31 30 31 30 31 31 30 31 30 31] (1- month))))
+
+(defun timezone-leap-year-p (year)
+  "Returns t if YEAR is a Gregorian leap year."
+  (or (and (zerop  (% year 4))
+	   (not (zerop (% year 100))))
+      (zerop (% year 400))))
+
+(defun timezone-day-number (month day year)
+  "Return the day number within the year of the date month/day/year."
+  (let ((day-of-year (+ day (* 31 (1- month)))))
+    (if (> month 2)
+	(progn
+	  (setq day-of-year (- day-of-year (/ (+ 23 (* 4 month)) 10)))
+	  (if (timezone-leap-year-p year)
+	      (setq day-of-year (1+ day-of-year)))))
+    day-of-year))
+
+(defun timezone-absolute-from-gregorian (month day year)
+  "The number of days between the Gregorian date 12/31/1 BC and month/day/year.
+The Gregorian date Sunday, December 31, 1 BC is imaginary."
+  (+ (timezone-day-number month day year);; Days this year
+     (* 365 (1- year));;	+ Days in prior years
+     (/ (1- year) 4);;		+ Julian leap years
+     (- (/ (1- year) 100));;	- century years
+     (/ (1- year) 400)));;	+ Gregorian leap years
+
+(defun timezone-abs (n)
+  (if (fboundp 'abs)
+      (abs n)
+    (if (< n 0) (- n) n)))
+
+(defun timezone-floor (n &optional divisor)
+  (if (fboundp 'floor)
+      (floor n divisor)
+    (if (null divisor)
+	(setq divisor 1))
+    (if (< n 0)
+	(- (/ (- divisor 1 n) divisor))
+      (/ n divisor))))
+
+;;; timezone.el ends here