[bpt/emacs.git] / lisp / timezone.el

;;; timezone.el --- time zone package for GNU Emacs

;; Copyright (C) 1990, 1991, 1992, 1993, 1996 Free Software Foundation, Inc.

;; Author: Masanobu Umeda
;; Maintainer: umerin@mse.kyutech.ac.jp
;; Keywords: news

;; This file is part of GNU Emacs.

;; GNU Emacs 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.

;; GNU Emacs 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 GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; 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)))
    ))

\f
;;
;; 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]
 (8) 1996-06-24 21:13:12 [GMT]"
 ;; 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
	    "\\([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
	   ;; This is most common in mail and news,
	   ;; so it is worth trying first.
	   (setq year 3 month 2 day 1 time 4 zone 5))
	  ((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
	    "\\([^ \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
	    "\\([^ \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))
	  ((string-match
	    "\\([0-9]+\\)-\\([0-9]+\\)-\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9]+:[0-9]+\\)[ \t]*\\([-+a-zA-Z0-9]+\\)" date)
	   ;; Styles: (8) with timezone.
	   (setq year 1 month 2 day 3 time 4 zone 5))
	  ((string-match
	    "\\([0-9]+\\)-\\([0-9]+\\)-\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9]+:[0-9]+\\)" date)
	   ;; Styles: (8) without timezone.
	   (setq year 1 month 2 day 3 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) 1)
	      (setq year (concat "190" (substring year -1 nil)))
	    (if (< (length year) 4)
		(setq year (concat "19" (substring year -2 nil)))))
          (setq month
		(if (= (aref date (+ (match-beginning month) 2)) ?-)
		    ;; Handle numeric months, spanning exactly two digits.
		    (substring date
			       (match-beginning month)
			       (+ (match-beginning month) 2))
 	          (let* ((string (substring date
					    (match-beginning month)
					    (+ (match-beginning month) 3)))
			 (monthnum
			  (cdr (assoc (upcase string) timezone-months-assoc))))
		    (if monthnum
			(int-to-string monthnum)
		      nil))))
	  (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 (and year month)
	(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"))
    ))

\f
;; 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 (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 719163)
	    ;; (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 (floor (/ seconds current-time-arithmetic-base)))
	 (hibase (* hi current-time-arithmetic-base))
	 (lo (floor (- seconds hibase))))
     (and (< (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 (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

;;; timezone.el ends here
Commit	Line	Data
be010748	1	;;; timezone.el --- time zone package for GNU Emacs
a47a5be5	2
ac4c237c	3	;; Copyright (C) 1990, 1991, 1992, 1993, 1996 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 RS	25
	26	;;; Code:
	27
	28	(provide 'timezone)
	29
	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.
d51c3cda RS	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)))
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.
d51c3cda RS	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)))
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 RS	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:
a47a5be5 RS	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
6b77e539	130	(4) 6 May 1992 1641-JST (Wednesday)
2f9a1ee2 RS	131	(5) 22-AUG-1993 10:59:12.82
2f9a1ee2 RS	132	(6) Thu, 11 Apr 16:17:12 91 [MET]
9d02faa7	133	(7) Mon, 6 Jul 16:47:20 T 1992 [MET]
ac4c237c MB	134	(8) 1996-06-24 21:13:12 [GMT]"
ac4c237c MB	135	;; Get rid of any text properties.
f4573839 RS	136	(and (stringp date)
	137	(or (text-properties-at 0 date)
	138	(next-property-change 0 date))
	139	(setq date (copy-sequence date))
	140	(set-text-properties 0 (length date) nil date))
a47a5be5 RS	141	(let ((date (or date ""))
	142	(year nil)
	143	(month nil)
	144	(day nil)
	145	(time nil)
	146	(zone nil)) ;This may be nil.
	147	(cond ((string-match
bcabbf77 RS	148	"\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]*\\([-+a-zA-Z0-9]+\\)" date)
	149	;; Styles: (1) and (2) with timezone and buggy timezone
	150	;; This is most common in mail and news,
	151	;; so it is worth trying first.
	152	(setq year 3 month 2 day 1 time 4 zone 5))
	153	((string-match
	154	"\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]*\\'" date)
	155	;; Styles: (1) and (2) without timezone
	156	(setq year 3 month 2 day 1 time 4 zone nil))
	157	((string-match
2f9a1ee2 RS	158	"\\([^ \t,]+\\),[ \t]+\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\(T[ \t]+\\\|\\)\\([0-9]+\\)[ \t]*\\'" date)
	159	;; Styles: (6) and (7) without timezone
	160	(setq year 6 month 3 day 2 time 4 zone nil))
	161	((string-match
	162	"\\([^ \t,]+\\),[ \t]+\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\(T[ \t]+\\\|\\)\\([0-9]+\\)[ \t]*\\([-+a-zA-Z0-9]+\\)" date)
	163	;; Styles: (6) and (7) with timezone and buggy timezone
	164	(setq year 6 month 3 day 2 time 4 zone 7))
a47a5be5 RS	165	((string-match
	166	"\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\([0-9]+\\)" date)
	167	;; Styles: (3) without timezone
	168	(setq year 4 month 1 day 2 time 3 zone nil))
	169	((string-match
	170	"\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\([-+a-zA-Z0-9]+\\)[ \t]+\\([0-9]+\\)" date)
6b77e539	171	;; Styles: (3) with timezone
a47a5be5 RS	172	(setq year 5 month 1 day 2 time 3 zone 4))
	173	((string-match
	174	"\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+\\)[ \t]*\\([-+a-zA-Z0-9]+\\)" date)
	175	;; Styles: (4) with timezone
	176	(setq year 3 month 2 day 1 time 4 zone 5))
6b77e539 RS	177	((string-match
	178	"\\([0-9]+\\)-\\([A-Za-z]+\\)-\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9]+:[0-9]+\\)\\.[0-9]+" date)
	179	;; Styles: (5) without timezone.
	180	(setq year 3 month 2 day 1 time 4 zone nil))
ac4c237c MB	181	((string-match
	182	"\\([0-9]+\\)-\\([0-9]+\\)-\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9]+:[0-9]+\\)[ \t]*\\([-+a-zA-Z0-9]+\\)" date)
	183	;; Styles: (8) with timezone.
	184	(setq year 1 month 2 day 3 time 4 zone 5))
	185	((string-match
	186	"\\([0-9]+\\)-\\([0-9]+\\)-\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9]+:[0-9]+\\)" date)
	187	;; Styles: (8) without timezone.
	188	(setq year 1 month 2 day 3 time 4 zone nil))
a47a5be5 RS	189	)
	190	(if year
	191	(progn
	192	(setq year
	193	(substring date (match-beginning year) (match-end year)))
	194	;; It is now Dec 1992. 8 years before the end of the World.
f8f5c5f4 RS	195	(if (= (length year) 1)
	196	(setq year (concat "190" (substring year -1 nil)))
	197	(if (< (length year) 4)
	198	(setq year (concat "19" (substring year -2 nil)))))
ac4c237c MB	199	(setq month
	200	(if (= (aref date (+ (match-beginning month) 2)) ?-)
	201	;; Handle numeric months, spanning exactly two digits.
	202	(substring date
	203	(match-beginning month)
	204	(+ (match-beginning month) 2))
dd713b75 RS	205	(let* ((string (substring date
	206	(match-beginning month)
	207	(+ (match-beginning month) 3)))
	208	(monthnum
	209	(cdr (assoc (upcase string) timezone-months-assoc))))
	210	(if monthnum
	211	(int-to-string monthnum)
	212	nil))))
a47a5be5 RS	213	(setq day
	214	(substring date (match-beginning day) (match-end day)))
	215	(setq time
	216	(substring date (match-beginning time) (match-end time)))))
	217	(if zone
	218	(setq zone
	219	(substring date (match-beginning zone) (match-end zone))))
	220	;; Return a vector.
dd713b75	221	(if (and year month)
a47a5be5 RS	222	(vector year month day time zone)
	223	(vector "0" "0" "0" "0" nil))
	224	))
	225
	226	(defun timezone-parse-time (time)
	227	"Parse TIME (HH:MM:SS) and return a vector [hour minute second].
	228	Recognize HH:MM:SS, HH:MM, HHMMSS, HHMM."
	229	(let ((time (or time ""))
	230	(hour nil)
	231	(minute nil)
	232	(second nil))
	233	(cond ((string-match "\\`\\([0-9]+\\):\\([0-9]+\\):\\([0-9]+\\)\\'" time)
	234	;; HH:MM:SS
	235	(setq hour 1 minute 2 second 3))
	236	((string-match "\\`\\([0-9]+\\):\\([0-9]+\\)\\'" time)
	237	;; HH:MM
	238	(setq hour 1 minute 2 second nil))
	239	((string-match "\\`\\([0-9][0-9]\\)\\([0-9][0-9]\\)\\([0-9][0-9]\\)\\'" time)
	240	;; HHMMSS
	241	(setq hour 1 minute 2 second 3))
	242	((string-match "\\`\\([0-9][0-9]\\)\\([0-9][0-9]\\)\\'" time)
	243	;; HHMM
	244	(setq hour 1 minute 2 second nil))
	245	)
	246	;; Return [hour minute second]
	247	(vector
	248	(if hour
	249	(substring time (match-beginning hour) (match-end hour)) "0")
	250	(if minute
	251	(substring time (match-beginning minute) (match-end minute)) "0")
	252	(if second
	253	(substring time (match-beginning second) (match-end second)) "0"))
	254	))
	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)
	273	(setq timezone (string-to-int timezone)))
	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))
	316	(year (string-to-int (aref date 0)))
13d76d1c RS	317	(year (cond ((< year 50)
	318	(+ year 2000))
	319	((< year 100)
	320	(+ year 1900))
	321	(t year)))
d51c3cda RS	322	(month (string-to-int (aref date 1)))
	323	(day (string-to-int (aref date 2)))
	324	(time (timezone-parse-time (aref date 3)))
	325	(hour (string-to-int (aref time 0)))
	326	(minute (string-to-int (aref time 1)))
	327	(second (string-to-int (aref time 2)))
	328	(local (or (aref date 4) local)) ;Use original if defined
	329	(timezone
	330	(or timezone
	331	(timezone-time-zone-from-absolute
	332	(timezone-absolute-from-gregorian month day year)
	333	(+ second (* 60 (+ minute (* 60 hour)))))))
	334	(diff (- (timezone-zone-to-minute timezone)
	335	(timezone-zone-to-minute local)))
	336	(minute (+ minute diff))
9b1868cc	337	(hour-fix (floor minute 60)))
a47a5be5	338	(setq hour (+ hour hour-fix))
d51c3cda RS	339	(setq minute (- minute (* 60 hour-fix)))
	340	;; HOUR may be larger than 24 or smaller than 0.
	341	(cond ((<= 24 hour) ;24 -> 00
	342	(setq hour (- hour 24))
	343	(setq day (1+ day))
	344	(if (< (timezone-last-day-of-month month year) day)
	345	(progn
	346	(setq month (1+ month))
	347	(setq day 1)
	348	(if (< 12 month)
	349	(progn
	350	(setq month 1)
	351	(setq year (1+ year))
	352	))
	353	)))
	354	((> 0 hour)
	355	(setq hour (+ hour 24))
	356	(setq day (1- day))
	357	(if (> 1 day)
	358	(progn
	359	(setq month (1- month))
	360	(if (> 1 month)
	361	(progn
	362	(setq month 12)
	363	(setq year (1- year))
	364	))
	365	(setq day (timezone-last-day-of-month month year))
	366	)))
	367	)
	368	(vector year month day hour minute second timezone)))
a47a5be5 RS	369
	370	;; Partly copied from Calendar program by Edward M. Reingold.
	371	;; Thanks a lot.
	372
	373	(defun timezone-last-day-of-month (month year)
	374	"The last day in MONTH during YEAR."
	375	(if (and (= month 2) (timezone-leap-year-p year))
	376	29
	377	(aref [31 28 31 30 31 30 31 31 30 31 30 31] (1- month))))
	378
	379	(defun timezone-leap-year-p (year)
	380	"Returns t if YEAR is a Gregorian leap year."
	381	(or (and (zerop (% year 4))
	382	(not (zerop (% year 100))))
	383	(zerop (% year 400))))
aa56d805	384
d51c3cda RS	385	(defun timezone-day-number (month day year)
	386	"Return the day number within the year of the date month/day/year."
	387	(let ((day-of-year (+ day (* 31 (1- month)))))
	388	(if (> month 2)
	389	(progn
	390	(setq day-of-year (- day-of-year (/ (+ 23 (* 4 month)) 10)))
	391	(if (timezone-leap-year-p year)
	392	(setq day-of-year (1+ day-of-year)))))
	393	day-of-year))
	394
	395	(defun timezone-absolute-from-gregorian (month day year)
	396	"The number of days between the Gregorian date 12/31/1 BC and month/day/year.
	397	The Gregorian date Sunday, December 31, 1 BC is imaginary."
	398	(+ (timezone-day-number month day year);; Days this year
	399	(* 365 (1- year));; + Days in prior years
	400	(/ (1- year) 4);; + Julian leap years
	401	(- (/ (1- year) 100));; - century years
	402	(/ (1- year) 400)));; + Gregorian leap years
	403
aa56d805	404	;;; timezone.el ends here