1 ;;; parse-time.el --- Parsing time strings
3 ;; Copyright (C) 1996 by Free Software Foundation, Inc.
5 ;; Author: Erik Naggum <erik@arcana.naggum.no>
8 ;; This file is part of GNU Emacs.
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)
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.
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, Inc., 59 Temple Place - Suite 330,
23 ;; Boston, MA 02111-1307, USA.
27 ;; With the introduction of the `encode-time', `decode-time', and
28 ;; `format-time-string' functions, dealing with time became simpler in
29 ;; Emacs. However, parsing time strings is still largely a matter of
30 ;; heuristics and no common interface has been designed.
32 ;; `parse-time-string' parses a time in a string and returns a list of 9
33 ;; values, just like `decode-time', where unspecified elements in the
34 ;; string are returned as nil. `encode-time' may be applied on these
35 ;; valuse to obtain an internal time value.
39 (eval-when-compile (require 'cl)) ;and ah ain't kiddin' 'bout it
41 (defvar parse-time-syntax (make-vector 256 nil))
42 (defvar parse-time-digits (make-vector 256 nil))
44 ;; Byte-compiler warnings
48 (unless (aref parse-time-digits ?0)
49 (loop for i from ?0 to ?9
50 do (aset parse-time-digits i (- i ?0))))
52 (unless (aref parse-time-syntax ?0)
53 (loop for i from ?0 to ?9
54 do (aset parse-time-syntax i ?0))
55 (loop for i from ?A to ?Z
56 do (aset parse-time-syntax i ?A))
57 (loop for i from ?a to ?z
58 do (aset parse-time-syntax i ?a))
59 (aset parse-time-syntax ?+ 1)
60 (aset parse-time-syntax ?- -1)
61 (aset parse-time-syntax ?: ?d)
64 (defsubst digit-char-p (char)
65 (aref parse-time-digits char))
67 (defsubst parse-time-string-chars (char)
68 (aref parse-time-syntax char))
70 (put 'parse-error 'error-conditions '(parse-error error))
71 (put 'parse-error 'error-message "Parsing error")
73 (defsubst parse-integer (string &optional start end)
74 "[CL] Parse and return the integer in STRING, or nil if none."
78 (end (or end (length string))))
80 (let ((sign (aref string index)))
81 (if (or (eq sign ?+) (eq sign ?-))
82 (setq sign (parse-time-string-chars sign)
85 (while (and (< index end)
86 (setq digit (digit-char-p (aref string index))))
87 (setq integer (+ (* integer 10) digit)
90 (signal 'parse-error `("not an integer"
91 ,(substring string (or start 0) end)))
94 (defun parse-time-tokenize (string)
95 "Tokenize STRING into substrings."
103 (while (and (< index end) ;skip invalid characters
104 (not (setq c (parse-time-string-chars (aref string index)))))
106 (setq start index all-digits (eq c ?0))
107 (while (and (< (incf index) end) ;scan valid characters
108 (setq c (parse-time-string-chars (aref string index))))
109 (setq all-digits (and all-digits (eq c ?0))))
111 (push (if all-digits (parse-integer string start index)
112 (substring string start index))
116 (defvar parse-time-months '(("jan" . 1) ("feb" . 2) ("mar" . 3)
117 ("apr" . 4) ("may" . 5) ("jun" . 6)
118 ("jul" . 7) ("aug" . 8) ("sep" . 9)
119 ("oct" . 10) ("nov" . 11) ("dec" . 12)))
120 (defvar parse-time-weekdays '(("sun" . 0) ("mon" . 1) ("tue" . 2)
121 ("wed" . 3) ("thu" . 4) ("fri" . 5) ("sat" . 6)))
122 (defvar parse-time-zoneinfo `(("z" 0) ("ut" 0) ("gmt" 0)
123 ("pst" ,(* -8 3600)) ("pdt" ,(* -7 3600) t)
124 ("mst" ,(* -7 3600)) ("mdt" ,(* -6 3600) t)
125 ("cst" ,(* -6 3600)) ("cdt" ,(* -5 3600) t)
126 ("est" ,(* -5 3600)) ("edt" ,(* -4 3600) t))
127 "(zoneinfo seconds-off daylight-savings-time-p)")
129 (defvar parse-time-rules
130 `(((6) parse-time-weekdays)
132 ((4) parse-time-months)
135 ,#'(lambda () (and (stringp elt)
138 (= (aref elt 5) ?:)))
140 ((8 7) parse-time-zoneinfo
141 ,#'(lambda () (car val))
142 ,#'(lambda () (cadr val)))
147 (or (= (aref elt 0) ?+) (= (aref elt 0) ?-))))
148 ,#'(lambda () (* 60 (+ (parse-integer elt 3 5)
149 (* 60 (parse-integer elt 1 3)))
150 (if (= (aref elt 0) ?-) -1 1))))
152 ,#'(lambda () (and (stringp elt)
155 (= (aref elt 7) ?-)))
158 ,#'(lambda () (and (stringp elt) (= (length elt) 5) (= (aref elt 2) ?:)))
159 [0 2] [3 5] ,#'(lambda () 0))
161 ,#'(lambda () (and (stringp elt)
163 (= (aref elt 1) ?:)))
164 [0 1] [2 4] ,#'(lambda () 0))
166 ,#'(lambda () (and (stringp elt)
168 (= (aref elt 1) ?:)))
170 ((5) (50 99) ,#'(lambda () (+ 1900 elt)))
171 ((5) (0 49) ,#'(lambda () (+ 2000 elt))))
172 "(slots predicate extractor...)")
174 (defun parse-time-string (string)
175 "Parse the time-string STRING into (SEC MIN HOUR DAY MON YEAR DOW DST TZ).
176 The values are identical to those of `decode-time', but any values that are
177 unknown are returned as nil."
178 (let ((time (list nil nil nil nil nil nil nil nil nil))
179 (temp (parse-time-tokenize (downcase string))))
181 (let ((elt (pop temp))
182 (rules parse-time-rules)
184 (while (and (not (null rules)) (not exit))
185 (let* ((rule (pop rules))
187 (predicate (pop rule))
189 (when (and (not (nth (car slots) time)) ;not already set
190 (setq val (cond ((and (consp predicate)
191 (not (eq (car predicate)
194 (<= (car predicate) elt)
195 (<= elt (cadr predicate))
199 (symbol-value predicate))))
200 ((funcall predicate)))))
203 (let ((new-val (and rule
204 (let ((this (pop rule)))
207 elt (aref this 0) (aref this 1))
209 (rplaca (nthcdr (pop slots) time) (or new-val val)))))))))
212 (provide 'parse-time)
214 ;;; parse-time.el ends here