code.delx.au - gnu-emacs/blob - lisp/timezone.el

   1 ;;; Timezone package for GNU Emacs
   2
   3 ;; Copyright (C) 1990, 1991, 1992, 1993 Free Software Foundation, Inc.
   4
   5 ;;; Author: Masanobu Umeda
   6 ;;; Maintainer: umerin@mse.kyutech.ac.jp
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software; you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation; either version 2, or (at your option)
  13 ;; any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs; see the file COPYING.  If not, write to
  22 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  23
  24 ;;; Code:
  25
  26 (provide 'timezone)
  27
  28 (defvar timezone-world-timezones
  29   '(("PST" .  -800)
  30     ("PDT" .  -700)
  31     ("MST" .  -700)
  32     ("MDT" .  -600)
  33     ("CST" .  -600)
  34     ("CDT" .  -500)
  35     ("EST" .  -500)
  36     ("EDT" .  -400)
  37     ("AST" .  -400)                     ;by <clamen@CS.CMU.EDU>
  38     ("NST" .  -330)                     ;by <clamen@CS.CMU.EDU>
  39     ("GMT" .  +000)
  40     ("BST" .  +100)
  41     ("MET" .  +100)
  42     ("EET" .  +200)
  43     ("JST" .  +900)
  44     ("GMT+1"  .  +100) ("GMT+2"  .  +200) ("GMT+3"  .  +300)
  45     ("GMT+4"  .  +400) ("GMT+5"  .  +500) ("GMT+6"  .  +600)
  46     ("GMT+7"  .  +700) ("GMT+8"  .  +800) ("GMT+9"  .  +900)
  47     ("GMT+10" . +1000) ("GMT+11" . +1100) ("GMT+12" . +1200) ("GMT+13" . +1300)
  48     ("GMT-1"  .  -100) ("GMT-2"  .  -200) ("GMT-3"  .  -300)
  49     ("GMT-4"  .  -400) ("GMT-5"  .  -500) ("GMT-6"  .  -600)
  50     ("GMT-7"  .  -700) ("GMT-8"  .  -800) ("GMT-9"  .  -900)
  51     ("GMT-10" . -1000) ("GMT-11" . -1100) ("GMT-12" . -1200))
  52   "*Time differentials of timezone from GMT in hour.")
  53
  54 (defvar timezone-months-assoc
  55   '(("JAN" .  1)("FEB" .  2)("MAR" .  3)
  56     ("APR" .  4)("MAY" .  5)("JUN" .  6)
  57     ("JUL" .  7)("AUG" .  8)("SEP" .  9)
  58     ("OCT" . 10)("NOV" . 11)("DEC" . 12))
  59   "Alist of first three letters of a month and its numerical representation.")
  60
  61 (defun timezone-make-date-arpa-standard (date &optional local timezone)
  62   "Convert DATE to an arpanet standard date.
  63 Optional 1st argumetn LOCAL specifies the default local timezone of the DATE.
  64 Optional 2nd argument TIMEZONE specifies a timezone to be represented in."
  65   (let* ((date   (timezone-parse-date date))
  66          (year   (string-to-int (aref date 0)))
  67          (month  (string-to-int (aref date 1)))
  68          (day    (string-to-int (aref date 2)))
  69          (time   (timezone-parse-time (aref date 3)))
  70          (hour   (string-to-int (aref time 0)))
  71          (minute (string-to-int (aref time 1)))
  72          (second (string-to-int (aref time 2)))
  73          (local  (or (aref date 4) local)) ;Use original if defined
  74          (timezone (or timezone local))
  75          (diff   (- (timezone-zone-to-minute timezone)
  76                     (timezone-zone-to-minute local)))
  77          (new    (timezone-fix-time year month day
  78                                     hour (+ minute diff) second)))
  79     (timezone-make-arpa-date (aref new 0) (aref new 1) (aref new 2)
  80                              (timezone-make-time-string
  81                               (aref new 3) (aref new 4) (aref new 5))
  82                              timezone)
  83     ))
  84
  85 (defun timezone-make-date-sortable (date &optional local timezone)
  86   "Convert DATE to a sortable date string.
  87 Optional 1st argumetn LOCAL specifies the default local timezone of the DATE.
  88 Optional 2nd argument TIMEZONE specifies a timezone to be represented in."
  89   (let* ((date   (timezone-parse-date date))
  90          (year   (string-to-int (aref date 0)))
  91          (month  (string-to-int (aref date 1)))
  92          (day    (string-to-int (aref date 2)))
  93          (time   (timezone-parse-time (aref date 3)))
  94          (hour   (string-to-int (aref time 0)))
  95          (minute (string-to-int (aref time 1)))
  96          (second (string-to-int (aref time 2)))
  97          (local  (or (aref date 4) local)) ;Use original if defined
  98          (timezone (or timezone local))
  99          (diff   (- (timezone-zone-to-minute timezone)
 100                     (timezone-zone-to-minute local)))
 101          (new    (timezone-fix-time year month day
 102                                     hour (+ minute diff) second)))
 103     (timezone-make-sortable-date (aref new 0) (aref new 1) (aref new 2)
 104                                  (timezone-make-time-string
 105                                   (aref new 3) (aref new 4) (aref new 5)))
 106     ))
 107
 108 \f
 109 ;;
 110 ;; Parsers and Constructors of Date and Time
 111 ;;
 112
 113 (defun timezone-make-arpa-date (year month day time &optional timezone)
 114   "Make arpanet standard date string from YEAR, MONTH, DAY, and TIME.
 115 Optional argument TIMEZONE specifies a time zone."
 116   (format "%02d %s %4d %s%s"
 117           day
 118           (capitalize (car (rassq month timezone-months-assoc)))
 119           ;;(- year (* (/ year 100) 100))       ;1990 -> 90
 120           (if (< year 100) (+ year 1900) year) ;90->1990
 121           time
 122           (if timezone (concat " " timezone) "")
 123           ))
 124
 125 (defun timezone-make-sortable-date (year month day time)
 126   "Make sortable date string from YEAR, MONTH, DAY, and TIME."
 127   (format "%4d%02d%02d%s"
 128           ;;(- year (* (/ year 100) 100))       ;1990 -> 90
 129           (if (< year 100) (+ year 1900) year) ;90->1990
 130           month day time))
 131
 132 (defun timezone-make-time-string (hour minute second)
 133   "Make time string from HOUR, MINUTE, and SECOND."
 134   (format "%02d:%02d:%02d" hour minute second))
 135
 136 (defun timezone-parse-date (date)
 137   "Parse DATE and return a vector [year month day time timezone].
 138 19 is prepended to year if necessary. Timezone may be NIL if nothing.
 139 Understand the following styles:
 140  (1) 14 Apr 89 03:20[:12] [GMT]
 141  (2) Fri, 17 Mar 89 4:01[:33] [GMT]
 142  (3) Mon Jan 16 16:12[:37] [GMT] 1989
 143  (4) 6 May 1992 1641-JST (Wednesday)"
 144   (let ((date (or date ""))
 145         (year nil)
 146         (month nil)
 147         (day nil)
 148         (time nil)
 149         (zone nil))                     ;This may be nil.
 150     (cond ((string-match
 151             "\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]*\\'" date)
 152            ;; Styles: (1) and (2) without timezone
 153            (setq year 3 month 2 day 1 time 4 zone nil))
 154           ((string-match
 155             "\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]*\\([-+a-zA-Z0-9]+\\)" date)
 156            ;; Styles: (1) and (2) with timezone and buggy timezone
 157            (setq year 3 month 2 day 1 time 4 zone 5))
 158           ((string-match
 159             "\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\([0-9]+\\)" date)
 160            ;; Styles: (3) without timezone
 161            (setq year 4 month 1 day 2 time 3 zone nil))
 162           ((string-match
 163             "\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+:[0-9:]+\\)[ \t]+\\([-+a-zA-Z0-9]+\\)[ \t]+\\([0-9]+\\)" date)
 164            ;; Styles: (3) with timezoen
 165            (setq year 5 month 1 day 2 time 3 zone 4))
 166           ((string-match
 167             "\\([0-9]+\\)[ \t]+\\([^ \t,]+\\)[ \t]+\\([0-9]+\\)[ \t]+\\([0-9]+\\)[ \t]*\\([-+a-zA-Z0-9]+\\)" date)
 168            ;; Styles: (4) with timezone
 169            (setq year 3 month 2 day 1 time 4 zone 5))
 170           )
 171     (if year
 172         (progn
 173           (setq year
 174                 (substring date (match-beginning year) (match-end year)))
 175           ;; It is now Dec 1992.  8 years before the end of the World.
 176           (if (< (length year) 4)
 177               (setq year (concat "19" (substring year -2 nil))))
 178           (setq month
 179                 (int-to-string
 180                  (cdr
 181                   (assoc
 182                    (upcase
 183                     ;; Don't use `match-end' in order to take 3
 184                     ;; letters from the beginning.
 185                     (substring date
 186                                (match-beginning month)
 187                                (+ (match-beginning month) 3)))
 188                    timezone-months-assoc))))
 189           (setq day
 190                 (substring date (match-beginning day) (match-end day)))
 191           (setq time
 192                 (substring date (match-beginning time) (match-end time)))))
 193     (if zone
 194         (setq zone
 195               (substring date (match-beginning zone) (match-end zone))))
 196     ;; Return a vector.
 197     (if year
 198         (vector year month day time zone)
 199       (vector "0" "0" "0" "0" nil))
 200     ))
 201
 202 (defun timezone-parse-time (time)
 203   "Parse TIME (HH:MM:SS) and return a vector [hour minute second].
 204 Recognize HH:MM:SS, HH:MM, HHMMSS, HHMM."
 205   (let ((time (or time ""))
 206         (hour nil)
 207         (minute nil)
 208         (second nil))
 209     (cond ((string-match "\\`\\([0-9]+\\):\\([0-9]+\\):\\([0-9]+\\)\\'" time)
 210            ;; HH:MM:SS
 211            (setq hour 1 minute 2 second 3))
 212           ((string-match "\\`\\([0-9]+\\):\\([0-9]+\\)\\'" time)
 213            ;; HH:MM
 214            (setq hour 1 minute 2 second nil))
 215           ((string-match "\\`\\([0-9][0-9]\\)\\([0-9][0-9]\\)\\([0-9][0-9]\\)\\'" time)
 216            ;; HHMMSS
 217            (setq hour 1 minute 2 second 3))
 218           ((string-match "\\`\\([0-9][0-9]\\)\\([0-9][0-9]\\)\\'" time)
 219            ;; HHMM
 220            (setq hour 1 minute 2 second nil))
 221           )
 222     ;; Return [hour minute second]
 223     (vector
 224      (if hour
 225          (substring time (match-beginning hour) (match-end hour)) "0")
 226      (if minute
 227          (substring time (match-beginning minute) (match-end minute)) "0")
 228      (if second
 229          (substring time (match-beginning second) (match-end second)) "0"))
 230     ))
 231
 232 \f
 233 ;; Miscellaneous
 234
 235 (defun timezone-zone-to-minute (timezone)
 236   "Translate TIMEZONE (in zone name or integer) to integer minute."
 237   (if timezone
 238       (progn
 239         (setq timezone
 240               (or (cdr (assoc (upcase timezone) timezone-world-timezones))
 241                   ;; +900
 242                   timezone))
 243         (if (stringp timezone)
 244             (setq timezone (string-to-int timezone)))
 245         ;; Taking account of minute in timezone.
 246         ;; HHMM -> MM
 247         ;;(+ (* 60 (/ timezone 100)) (% timezone 100))
 248         ;; ANSI C compliance about truncation of integer division
 249         ;; by eggert@twinsun.com (Paul Eggert)
 250         (let* ((abszone (max timezone (- timezone)))
 251                (minutes (+ (* 60 (/ abszone 100)) (% abszone 100))))
 252           (if (< timezone 0) (- minutes) minutes)))
 253     0))
 254
 255 (defun timezone-fix-time (year month day hour minute second)
 256   "Fix date and time."
 257   ;; MINUTE may be larger than 60 or smaller than -60.
 258   (let ((hour-fix
 259          (if (< minute 0)
 260              ;;(/ (- minute 59) 60) (/ minute 60)
 261              ;; ANSI C compliance about truncation of integer division
 262              ;; by eggert@twinsun.com (Paul Eggert)
 263              (- (/ (- 59 minute) 60)) (/ minute 60))))
 264     (setq hour (+ hour hour-fix))
 265     (setq minute (- minute (* 60 hour-fix))))
 266   ;; HOUR may be larger than 24 or smaller than 0.
 267   (cond ((<= 24 hour)                   ;24 -> 00
 268          (setq hour (- hour 24))
 269          (setq day  (1+ day))
 270          (if (< (timezone-last-day-of-month month year) day)
 271              (progn
 272                (setq month (1+ month))
 273                (setq day 1)
 274                (if (< 12 month)
 275                    (progn
 276                      (setq month 1)
 277                      (setq year (1+ year))
 278                      ))
 279                )))
 280         ((> 0 hour)
 281          (setq hour (+ hour 24))
 282          (setq day  (1- day))
 283          (if (> 1 day)
 284              (progn
 285                (setq month (1- month))
 286                (if (> 1 month)
 287                    (progn
 288                      (setq month 12)
 289                      (setq year (1- year))
 290                      ))
 291                (setq day (timezone-last-day-of-month month year))
 292                )))
 293         )
 294   (vector year month day hour minute second))
 295
 296 ;; Partly copied from Calendar program by Edward M. Reingold.
 297 ;; Thanks a lot.
 298
 299 (defun timezone-last-day-of-month (month year)
 300   "The last day in MONTH during YEAR."
 301   (if (and (= month 2) (timezone-leap-year-p year))
 302       29
 303     (aref [31 28 31 30 31 30 31 31 30 31 30 31] (1- month))))
 304
 305 (defun timezone-leap-year-p (year)
 306   "Returns t if YEAR is a Gregorian leap year."
 307   (or (and (zerop  (% year 4))
 308            (not (zerop (% year 100))))
 309       (zerop (% year 400))))
 310
 311 ;;; timezone.el ends here