src/code/format-time.lisp

   1 ;;;; time printing routines built upon the Common Lisp FORMAT function
   2
   3 ;;;; This software is part of the SBCL system. See the README file for
   4 ;;;; more information.
   5 ;;;;
   6 ;;;; This software is derived from the CMU CL system, which was
   7 ;;;; written at Carnegie Mellon University and released into the
   8 ;;;; public domain. The software is in the public domain and is
   9 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
  10 ;;;; files for more information.
  11
  12 (in-package "SB!IMPL")
  13
  14 (defparameter *abbrev-weekday-table*
  15   #("Mon" "Tue" "Wed" "Thu" "Fri" "Sat" "Sun"))
  16
  17 (defparameter *long-weekday-table*
  18   #("Monday" "Tuesday" "Wednesday" "Thursday" "Friday" "Saturday" "Sunday"))
  19
  20 (defparameter *abbrev-month-table*
  21   #("Jan" "Feb" "Mar" "Apr" "May" "Jun" "Jul" "Aug" "Sep" "Oct" "Nov" "Dec"))
  22
  23 (defparameter *long-month-table*
  24   #("January" "February" "March" "April" "May" "June" "July" "August"
  25    "September" "October" "November" "December"))
  26
  27 ;;; The timezone table is incomplete but workable.
  28 (defparameter *timezone-table*
  29   #("GMT" "" "" "" "" "EST" "CST" "MST" "PST"))
  30
  31 (defparameter *daylight-table*
  32   #(nil nil nil nil nil "EDT" "CDT" "MDT" "PDT"))
  33
  34 ;;; VALID-DESTINATION-P ensures the destination stream is okay for the
  35 ;;; FORMAT function.
  36 (defun valid-destination-p (destination)
  37   (or (not destination)
  38       (eq destination t)
  39       (streamp destination)
  40       (and (stringp destination)
  41            (array-has-fill-pointer-p destination))))
  42
  43 ;;; CMU CL made the default style :SHORT here. I've changed that to :LONG, on
  44 ;;; the theory that since the 8/7/1999 style is hard to decode unambiguously,
  45 ;;; you should have to ask for it explicitly. (I prefer YYYYMMDD myself, since
  46 ;;; it sorts properly.:-) -- WHN 19990831
  47 ;;;
  48 ;;; FIXME: On the CMU CL mailing list 30 Jan 2000, Pierre Mai suggested
  49 ;;;   OTOH it probably wouldn't be a major problem to change compile-file to
  50 ;;;   use for example :long, so that the output would be Month DD, YYYY, or
  51 ;;;   even better to extend format-universal-time with a flag to output ISO
  52 ;;;   8601 formats (like e.g. :iso-8601 and :iso-8601-short) and migrate
  53 ;;;   slowly towards ISO dates in the user code...
  54 ;;; The :ISO-8601 and :ISO-8601-SHORT options sound sensible to me. Maybe
  55 ;;; someone will do them for CMU CL and we can steal them for SBCL.
  56 (defun format-universal-time (destination universal-time
  57                                           &key
  58                                           (timezone nil)
  59                                           (style :long)
  60                                           (date-first t)
  61                                           (print-seconds t)
  62                                           (print-meridian t)
  63                                           (print-timezone t)
  64                                           (print-weekday t))
  65   #!+sb-doc
  66   "Format-Universal-Time formats a string containing the time and date
  67    given by universal-time in a common manner. The destination is any
  68    destination which can be accepted by the Format function. The
  69    timezone keyword is an integer specifying hours west of Greenwich.
  70    The style keyword can be :SHORT (numeric date), :LONG (months and
  71    weekdays expressed as words), :ABBREVIATED (like :LONG but words are
  72    abbreviated), or :GOVERNMENT (of the form \"XX Month XXXX XX:XX:XX\")
  73    The &KEY argument :DATE-FIRST, if NIL, will print the time first instead
  74    of the date (the default). The PRINT- keywords, if NIL, inhibit
  75    the printing of the obvious part of the time/date."
  76   (unless (valid-destination-p destination)
  77     (error "~A: Not a valid format destination." destination))
  78   (unless (integerp universal-time)
  79     (error "~A: Universal-Time should be an integer." universal-time))
  80   (when timezone
  81     (unless (and (rationalp timezone) (<= -24 timezone 24))
  82       (error "~A: Timezone should be a rational between -24 and 24." timezone))
  83     (unless (zerop (rem timezone 1/3600))
  84       (error "~A: Timezone is not a second (1/3600) multiple." timezone)))
  85
  86   (multiple-value-bind (secs mins hours day month year dow dst tz)
  87       (if timezone
  88           (decode-universal-time universal-time timezone)
  89           (decode-universal-time universal-time))
  90     (declare (fixnum secs mins hours day month year dow))
  91     (let ((time-string "~2,'0D:~2,'0D")
  92           (date-string
  93            (case style
  94              (:short "~D/~D/~D")                ;;  MM/DD/Y
  95              ((:abbreviated :long) "~A ~D, ~D") ;;  Month DD, Y
  96              (:government "~2,'0D ~:@(~A~) ~D") ;;  DD MON Y
  97              (t
  98               (error "~A: Unrecognized :style keyword value." style))))
  99           (time-args
 100            (list mins (max (mod hours 12) (1+ (mod (1- hours) 12)))))
 101           (date-args (case style
 102                        (:short
 103                         (list month day year))
 104                        (:abbreviated
 105                         (list (svref *abbrev-month-table* (1- month)) day year))
 106                        (:long
 107                         (list (svref *long-month-table* (1- month)) day year))
 108                        (:government
 109                         (list day (svref *abbrev-month-table* (1- month))
 110                               year)))))
 111       (declare (simple-string time-string date-string))
 112       (when print-weekday
 113         (push (case style
 114                 ((:short :long) (svref *long-weekday-table* dow))
 115                 (:abbreviated (svref *abbrev-weekday-table* dow))
 116                 (:government (svref *abbrev-weekday-table* dow)))
 117               date-args)
 118         (setq date-string
 119               (concatenate 'simple-string "~A, " date-string)))
 120       (when (or print-seconds (eq style :government))
 121         (push secs time-args)
 122         (setq time-string
 123               (concatenate 'simple-string time-string ":~2,'0D")))
 124       (when print-meridian
 125         (push (signum (floor hours 12)) time-args)
 126         (setq time-string
 127               (concatenate 'simple-string time-string " ~[AM~;PM~]")))
 128       (apply #'format destination
 129              (if date-first
 130                  (concatenate 'simple-string date-string " " time-string
 131                               (if print-timezone " ~A"))
 132                  (concatenate 'simple-string time-string " " date-string
 133                               (if print-timezone " ~A")))
 134              (if date-first
 135                  (nconc date-args (nreverse time-args)
 136                         (if print-timezone
 137                             (list (timezone-name dst tz))))
 138                  (nconc (nreverse time-args) date-args
 139                         (if print-timezone
 140                             (list (timezone-name dst tz)))))))))
 141
 142 (defun timezone-name (dst tz)
 143   (if (and (integerp tz)
 144            (or (and dst (= tz 0))
 145                (<= 5 tz 8)))
 146       (svref (if dst *daylight-table* *timezone-table*) tz)
 147       (multiple-value-bind (rest seconds) (truncate (* tz 60 60) 60)
 148         (multiple-value-bind (hours minutes) (truncate rest 60)
 149           (format nil "[~C~D~@[~*:~2,'0D~@[~*:~2,'0D~]~]]"
 150                   (if (minusp tz) #\- #\+)
 151                   (abs hours)
 152                   (not (and (zerop minutes) (zerop seconds)))
 153                   (abs minutes)
 154                   (not (zerop seconds))
 155                   (abs seconds))))))
 156
 157 (defun format-decoded-time (destination seconds minutes hours
 158                                           day month year
 159                                           &key (timezone nil)
 160                                           (style :short)
 161                                           (date-first t)
 162                                           (print-seconds t)
 163                                           (print-meridian t)
 164                                           (print-timezone t)
 165                                           (print-weekday t))
 166   #!+sb-doc
 167   "FORMAT-DECODED-TIME formats a string containing decoded time
 168    expressed in a humanly-readable manner. The destination is any
 169    destination which can be accepted by the FORMAT function. The
 170    timezone keyword is an integer specifying hours west of Greenwich.
 171    The style keyword can be :SHORT (numeric date), :LONG (months and
 172    weekdays expressed as words), or :ABBREVIATED (like :LONG but words are
 173    abbreviated). The keyword DATE-FIRST, if NIL, will cause the time
 174    to be printed first instead of the date (the default). The PRINT-
 175    keywords, if nil, inhibit the printing of certain semi-obvious
 176    parts of the string."
 177   (unless (valid-destination-p destination)
 178     (error "~A: Not a valid format destination." destination))
 179   (unless (and (integerp seconds) (<= 0 seconds 59))
 180     (error "~A: Seconds should be an integer between 0 and 59." seconds))
 181   (unless (and (integerp minutes) (<= 0 minutes 59))
 182     (error "~A: Minutes should be an integer between 0 and 59." minutes))
 183   (unless (and (integerp hours) (<= 0 hours 23))
 184     (error "~A: Hours should be an integer between 0 and 23." hours))
 185   (unless (and (integerp day) (<= 1 day 31))
 186     (error "~A: Day should be an integer between 1 and 31." day))
 187   (unless (and (integerp month) (<= 1 month 12))
 188     (error "~A: Month should be an integer between 1 and 12." month))
 189   (unless (and (integerp year) (plusp year))
 190     (error "~A: Hours should be an non-negative integer." year))
 191   (when timezone
 192     (unless (and (integerp timezone) (<= 0 timezone 32))
 193       (error "~A: Timezone should be an integer between 0 and 32."
 194              timezone)))
 195   (format-universal-time destination
 196    (encode-universal-time seconds minutes hours day month year)
 197    :timezone timezone :style style :date-first date-first
 198    :print-seconds print-seconds :print-meridian print-meridian
 199    :print-timezone print-timezone :print-weekday print-weekday))