lisp/calendar/parse-time.el

   1 ;;; parse-time.el --- parsing time strings
   2
   3 ;; Copyright (C) 1996, 2000-2015 Free Software Foundation, Inc.
   4
   5 ;; Author: Erik Naggum <erik@naggum.no>
   6 ;; Keywords: util
   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 3 of the License, or
  13 ;; (at your option) 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.  If not, see <http://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;; With the introduction of the `encode-time', `decode-time', and
  26 ;; `format-time-string' functions, dealing with time became simpler in
  27 ;; Emacs.  However, parsing time strings is still largely a matter of
  28 ;; heuristics and no common interface has been designed.
  29
  30 ;; `parse-time-string' parses a time in a string and returns a list of 9
  31 ;; values, just like `decode-time', where unspecified elements in the
  32 ;; string are returned as nil.  `encode-time' may be applied on these
  33 ;; values to obtain an internal time value.
  34
  35 ;;; Code:
  36
  37 (require 'cl-lib)
  38
  39 ;; Byte-compiler warnings
  40 (defvar parse-time-elt)
  41 (defvar parse-time-val)
  42
  43 (defsubst parse-time-string-chars (char)
  44   (save-match-data
  45     (let (case-fold-search str)
  46       (cond ((eq char ?+) 1)
  47             ((eq char ?-) -1)
  48             ((eq char ?:) ?d)
  49             ((string-match "[[:upper:]]" (setq str (string char))) ?A)
  50             ((string-match "[[:lower:]]" str) ?a)
  51             ((string-match "[[:digit:]]" str) ?0)))))
  52
  53 (defun parse-time-tokenize (string)
  54   "Tokenize STRING into substrings."
  55   (let ((start nil)
  56         (end (length string))
  57         (all-digits nil)
  58         (list ())
  59         (index 0)
  60         (c nil))
  61     (while (< index end)
  62       (while (and (< index end)         ;Skip invalid characters.
  63                   (not (setq c (parse-time-string-chars (aref string index)))))
  64         (cl-incf index))
  65       (setq start index all-digits (eq c ?0))
  66       (while (and (< (cl-incf index) end)       ;Scan valid characters.
  67                   (setq c (parse-time-string-chars (aref string index))))
  68         (setq all-digits (and all-digits (eq c ?0))))
  69       (if (<= index end)
  70           (push (if all-digits (cl-parse-integer string :start start :end index)
  71                   (substring string start index))
  72                 list)))
  73     (nreverse list)))
  74
  75 (defvar parse-time-months '(("jan" . 1) ("feb" . 2) ("mar" . 3)
  76                             ("apr" . 4) ("may" . 5) ("jun" . 6)
  77                             ("jul" . 7) ("aug" . 8) ("sep" . 9)
  78                             ("oct" . 10) ("nov" . 11) ("dec" . 12)
  79                             ("january" . 1) ("february" . 2)
  80                             ("march" . 3) ("april" . 4) ("june" . 6)
  81                             ("july" . 7) ("august" . 8)
  82                             ("september" . 9) ("october" . 10)
  83                             ("november" . 11) ("december" . 12)))
  84 (defvar parse-time-weekdays '(("sun" . 0) ("mon" . 1) ("tue" . 2)
  85                               ("wed" . 3) ("thu" . 4) ("fri" . 5)
  86                               ("sat" . 6) ("sunday" . 0) ("monday" . 1)
  87                               ("tuesday" . 2) ("wednesday" . 3)
  88                               ("thursday" . 4) ("friday" . 5)
  89                               ("saturday" . 6)))
  90 (defvar parse-time-zoneinfo `(("z" 0) ("ut" 0) ("gmt" 0)
  91                               ("pst" ,(* -8 3600)) ("pdt" ,(* -7 3600) t)
  92                               ("mst" ,(* -7 3600)) ("mdt" ,(* -6 3600) t)
  93                               ("cst" ,(* -6 3600)) ("cdt" ,(* -5 3600) t)
  94                               ("est" ,(* -5 3600)) ("edt" ,(* -4 3600) t))
  95   "(zoneinfo seconds-off daylight-savings-time-p)")
  96
  97 (defvar parse-time-rules
  98   `(((6) parse-time-weekdays)
  99     ((3) (1 31))
 100     ((4) parse-time-months)
 101     ((5) (100 ,most-positive-fixnum))
 102     ((2 1 0)
 103      ,#'(lambda () (and (stringp parse-time-elt)
 104                         (= (length parse-time-elt) 8)
 105                         (= (aref parse-time-elt 2) ?:)
 106                         (= (aref parse-time-elt 5) ?:)))
 107      [0 2] [3 5] [6 8])
 108     ((8 7) parse-time-zoneinfo
 109      ,#'(lambda () (car parse-time-val))
 110      ,#'(lambda () (cadr parse-time-val)))
 111     ((8)
 112      ,#'(lambda ()
 113           (and (stringp parse-time-elt)
 114                (= 5 (length parse-time-elt))
 115                (or (= (aref parse-time-elt 0) ?+)
 116                    (= (aref parse-time-elt 0) ?-))))
 117      ,#'(lambda () (* 60 (+ (cl-parse-integer parse-time-elt :start 3 :end 5)
 118                             (* 60 (cl-parse-integer parse-time-elt :start 1 :end 3)))
 119                       (if (= (aref parse-time-elt 0) ?-) -1 1))))
 120     ((5 4 3)
 121      ,#'(lambda () (and (stringp parse-time-elt)
 122                         (= (length parse-time-elt) 10)
 123                         (= (aref parse-time-elt 4) ?-)
 124                         (= (aref parse-time-elt 7) ?-)))
 125      [0 4] [5 7] [8 10])
 126     ((2 1 0)
 127      ,#'(lambda () (and (stringp parse-time-elt)
 128                         (= (length parse-time-elt) 5)
 129                         (= (aref parse-time-elt 2) ?:)))
 130      [0 2] [3 5] ,#'(lambda () 0))
 131     ((2 1 0)
 132      ,#'(lambda () (and (stringp parse-time-elt)
 133                         (= (length parse-time-elt) 4)
 134                         (= (aref parse-time-elt 1) ?:)))
 135      [0 1] [2 4] ,#'(lambda () 0))
 136     ((2 1 0)
 137      ,#'(lambda () (and (stringp parse-time-elt)
 138                         (= (length parse-time-elt) 7)
 139                         (= (aref parse-time-elt 1) ?:)))
 140      [0 1] [2 4] [5 7])
 141     ((5) (50 110) ,#'(lambda () (+ 1900 parse-time-elt)))
 142     ((5) (0 49) ,#'(lambda () (+ 2000 parse-time-elt))))
 143   "(slots predicate extractor...)")
 144 ;;;###autoload(put 'parse-time-rules 'risky-local-variable t)
 145
 146 ;;;###autoload
 147 (defun parse-time-string (string)
 148   "Parse the time-string STRING into (SEC MIN HOUR DAY MON YEAR DOW DST TZ).
 149 The values are identical to those of `decode-time', but any values that are
 150 unknown are returned as nil."
 151   (let ((time (list nil nil nil nil nil nil nil nil nil))
 152         (temp (parse-time-tokenize (downcase string))))
 153     (while temp
 154       (let ((parse-time-elt (pop temp))
 155             (rules parse-time-rules)
 156             (exit nil))
 157         (while (and rules (not exit))
 158           (let* ((rule (pop rules))
 159                  (slots (pop rule))
 160                  (predicate (pop rule))
 161                  (parse-time-val))
 162             (when (and (not (nth (car slots) time)) ;not already set
 163                        (setq parse-time-val
 164                              (cond ((and (consp predicate)
 165                                          (not (eq (car predicate)
 166                                                   'lambda)))
 167                                     (and (numberp parse-time-elt)
 168                                          (<= (car predicate) parse-time-elt)
 169                                          (<= parse-time-elt (cadr predicate))
 170                                          parse-time-elt))
 171                                    ((symbolp predicate)
 172                                     (cdr (assoc parse-time-elt
 173                                                 (symbol-value predicate))))
 174                                    ((funcall predicate)))))
 175               (setq exit t)
 176               (while slots
 177                 (let ((new-val (if rule
 178                                    (let ((this (pop rule)))
 179                                      (if (vectorp this)
 180                                          (cl-parse-integer
 181                                           parse-time-elt
 182                                           :start (aref this 0)
 183                                           :end (aref this 1))
 184                                        (funcall this)))
 185                                  parse-time-val)))
 186                   (rplaca (nthcdr (pop slots) time) new-val))))))))
 187     time))
 188
 189 (defconst parse-time-iso8601-regexp
 190   (let* ((dash "-?")
 191          (colon ":?")
 192          (4digit "\\([0-9][0-9][0-9][0-9]\\)")
 193          (2digit "\\([0-9][0-9]\\)")
 194          (date-fullyear 4digit)
 195          (date-month 2digit)
 196          (date-mday 2digit)
 197          (time-hour 2digit)
 198          (time-minute 2digit)
 199          (time-second 2digit)
 200          (time-secfrac "\\(\\.[0-9]+\\)?")
 201          (time-numoffset (concat "[-+]\\(" time-hour "\\):" time-minute))
 202          (time-offset (concat "Z" time-numoffset))
 203          (partial-time (concat time-hour colon time-minute colon time-second
 204                                time-secfrac))
 205          (full-date (concat date-fullyear dash date-month dash date-mday))
 206          (full-time (concat partial-time time-offset))
 207          (date-time (concat full-date "T" full-time)))
 208     (list (concat "^" full-date)
 209           (concat "T" partial-time)
 210           (concat "Z" time-numoffset)))
 211   "List of regular expressions matching ISO 8601 dates.
 212 1st regular expression matches the date.
 213 2nd regular expression matches the time.
 214 3rd regular expression matches the (optional) timezone specification.")
 215
 216 (defun parse-iso8601-time-string (date-string)
 217   (let* ((date-re (nth 0 parse-time-iso8601-regexp))
 218          (time-re (nth 1 parse-time-iso8601-regexp))
 219          (tz-re (nth 2 parse-time-iso8601-regexp))
 220          re-start
 221          time seconds minute hour fractional-seconds
 222          day month year day-of-week dst tz)
 223     ;; We need to populate 'time' with
 224     ;; (SEC MIN HOUR DAY MON YEAR DOW DST TZ)
 225
 226     ;; Nobody else handles iso8601 correctly, let's do it ourselves.
 227     (when (string-match date-re date-string re-start)
 228       (setq year (string-to-number (match-string 1 date-string))
 229             month (string-to-number (match-string 2 date-string))
 230             day (string-to-number (match-string 3 date-string))
 231             re-start (match-end 0))
 232       (when (string-match time-re date-string re-start)
 233         (setq hour (string-to-number (match-string 1 date-string))
 234               minute (string-to-number (match-string 2 date-string))
 235               seconds (string-to-number (match-string 3 date-string))
 236               fractional-seconds (string-to-number (or
 237                                                     (match-string 4 date-string)
 238                                                     "0"))
 239               re-start (match-end 0))
 240         (when (string-match tz-re date-string re-start)
 241           (setq tz (match-string 1 date-string)))
 242         (setq time (list seconds minute hour day month year day-of-week dst tz))))
 243
 244     ;; Fall back to having Gnus do fancy things for us.
 245     (when (not time)
 246       (setq time (parse-time-string date-string)))
 247
 248     (and time
 249          (apply 'encode-time time))))
 250
 251 (provide 'parse-time)
 252
 253 ;;; parse-time.el ends here