mirror/emacs
1
0
Fork 0
mirror of https://git.savannah.gnu.org/git/emacs.git synced 2024-11-25 07:28:20 +00:00
Code Issues Releases Activity
af029cdb3a
emacs/lisp/timezone.el
Po Lu 8e1c56ae46 ; Add 2024 to copyright years
2024-01-02 09:47:10 +08:00

396 lines
16 KiB
EmacsLisp
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

;;; timezone.el --- time zone package for GNU Emacs -*- lexical-binding: t -*-
;; Copyright (C) 1990-1993, 1996, 1999, 2001-2024 Free Software
;; Foundation, Inc.
;; Author: Masanobu Umeda <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 3 of the License, 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. If not, see <https://www.gnu.org/licenses/>.
;;; Commentary:
;;; Code:
(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 2nd argument LOCAL specifies the default local timezone of the DATE;
if nil, GMT is assumed.
Optional 3rd 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 2nd argument LOCAL specifies the default local timezone of the DATE;
if nil, GMT is assumed.
Optional 3rd 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)
(format-time-string "%z" 0 (or timezone 0))
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].
Two-digit dates are `windowed'. Those <69 have 2000 added; otherwise 1900
is added. Three-digit dates have 1900 added.
TIMEZONE is nil for DATEs without a zone field.
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]
(9) 1996-06-24 21:13-ZONE
(10) 19960624T211312"
;; 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]+\\)?[ \t]+\\([-+a-zA-Z0-9]+\\)" date)
;; Styles: (5) with timezone.
(setq year 3 month 2 day 1 time 4 zone 6))
((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]\\{4\\}\\)-?\\([0-9]\\{0,2\\}\\)-?\\([0-9]\\{0,2\\}\\)[T \t]+\\([0-9]\\{0,2\\}:?[0-9]\\{0,2\\}:?[0-9]\\{0,2\\}\\)[ \t]*\\([-+a-zA-Z]+[0-9:]*\\)" date)
;; Styles: (8) with timezone with a colon in it.
(setq year 1 month 2 day 3 time 4 zone 5))
((string-match
"\\([0-9]\\{4\\}\\)-?\\([0-9]\\{0,2\\}\\)-?\\([0-9]\\{0,2\\}\\)[T \t]+\\([0-9]+:?[0-9]+:?[0-9]+\\)" date)
;; Styles: (8) without timezone.
(setq year 1 month 2 day 3 time 4 zone nil))
)
(when year
(setq year (match-string year date))
;; Guess ambiguous years. Assume years < 69 don't predate the
;; Unix Epoch, so are 2000+. Three-digit years are assumed to
;; be relative to 1900.
(when (< (length year) 4)
(let ((y (string-to-number year)))
(when (< y 69)
(setq y (+ y 100)))
(setq year (int-to-string (+ 1900 y)))))
(setq month
(if (or (= (aref date (+ (match-beginning month) 2)) ?-)
(let ((n (string-to-number
(char-to-string
(aref date (+ (match-beginning month) 2))))))
(= (aref (number-to-string n) 0)
(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))))
(when monthnum
(int-to-string monthnum)))))
(setq day (match-string day date))
(setq time (match-string time date)))
(when zone (setq zone (match-string zone date)))
;; 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 minute second)
(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 (match-string hour time) "0")
(if minute (match-string minute time) "0")
(if second (match-string second time) "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-number 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 Lisp timestamp 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 86400)
(day-seconds (* days seconds-per-day)))
(condition-case nil (time-add day-seconds seconds)
(range-error))))
(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."
(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-number (aref date 0)))
(year (cond ((< year 69)
(+ year 2000))
((< year 100)
(+ year 1900))
((< year 1000) ; possible 3-digit years.
(+ year 1900))
(t year)))
(month (string-to-number (aref date 1)))
(day (string-to-number (aref date 2)))
(time (timezone-parse-time (aref date 3)))
(hour (string-to-number (aref time 0)))
(minute (string-to-number (aref time 1)))
(second (string-to-number (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))
(when (< (timezone-last-day-of-month month year) day)
(setq month (1+ month))
(setq day 1)
(when (< 12 month)
(setq month 1)
(setq year (1+ year)))))
((> 0 hour)
(setq hour (+ hour 24))
(setq day (1- day))
(when (> 1 day)
(setq month (1- month))
(when (> 1 month)
(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)
"Return 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
(provide 'timezone)
;;; timezone.el ends here
Reference in New Issue View Git Blame Copy Permalink