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