1 ;;; parse-time.el --- Parsing time strings
3 ;; Copyright (C) 1996, 2000, 2001, 2002, 2003, 2004, 2005
4 ;; Free Software Foundation, Inc.
6 ;; Author: Erik Naggum <erik@naggum.no>
9 ;; This file is part of GNU Emacs.
11 ;; GNU Emacs is free software; you can redistribute it and/or modify
12 ;; it under the terms of the GNU General Public License as published by
13 ;; the Free Software Foundation; either version 2, or (at your option)
16 ;; GNU Emacs is distributed in the hope that it will be useful,
17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 ;; GNU General Public License for more details.
21 ;; You should have received a copy of the GNU General Public License
22 ;; along with GNU Emacs; see the file COPYING. If not, write to
23 ;; the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
24 ;; Boston, MA 02110-1301, USA.
28 ;; With the introduction of the `encode-time', `decode-time', and
29 ;; `format-time-string' functions, dealing with time became simpler in
30 ;; Emacs. However, parsing time strings is still largely a matter of
31 ;; heuristics and no common interface has been designed.
33 ;; `parse-time-string' parses a time in a string and returns a list of 9
34 ;; values, just like `decode-time', where unspecified elements in the
35 ;; string are returned as nil. `encode-time' may be applied on these
36 ;; values to obtain an internal time value.
40 (eval-when-compile (require 'cl)) ;and ah ain't kiddin' 'bout it
42 (defvar parse-time-syntax (make-vector 256 nil))
43 (defvar parse-time-digits (make-vector 256 nil))
45 ;; Byte-compiler warnings
49 (unless (aref parse-time-digits ?0)
50 (loop for i from ?0 to ?9
51 do (aset parse-time-digits i (- i ?0))))
53 (unless (aref parse-time-syntax ?0)
54 (loop for i from ?0 to ?9
55 do (aset parse-time-syntax i ?0))
56 (loop for i from ?A to ?Z
57 do (aset parse-time-syntax i ?A))
58 (loop for i from ?a to ?z
59 do (aset parse-time-syntax i ?a))
60 (aset parse-time-syntax ?+ 1)
61 (aset parse-time-syntax ?- -1)
62 (aset parse-time-syntax ?: ?d)
65 (defsubst digit-char-p (char)
66 (aref parse-time-digits char))
68 (defsubst parse-time-string-chars (char)
69 (aref parse-time-syntax char))
71 (put 'parse-error 'error-conditions '(parse-error error))
72 (put 'parse-error 'error-message "Parsing error")
74 (defsubst parse-integer (string &optional start end)
75 "[CL] Parse and return the integer in STRING, or nil if none."
79 (end (or end (length string))))
81 (let ((sign (aref string index)))
82 (if (or (eq sign ?+) (eq sign ?-))
83 (setq sign (parse-time-string-chars sign)
86 (while (and (< index end)
87 (setq digit (digit-char-p (aref string index))))
88 (setq integer (+ (* integer 10) digit)
91 (signal 'parse-error `("not an integer"
92 ,(substring string (or start 0) end)))
95 (defun parse-time-tokenize (string)
96 "Tokenize STRING into substrings."
104 (while (and (< index end) ;skip invalid characters
105 (not (setq c (parse-time-string-chars (aref string index)))))
107 (setq start index all-digits (eq c ?0))
108 (while (and (< (incf index) end) ;scan valid characters
109 (setq c (parse-time-string-chars (aref string index))))
110 (setq all-digits (and all-digits (eq c ?0))))
112 (push (if all-digits (parse-integer string start index)
113 (substring string start index))
117 (defvar parse-time-months '(("jan" . 1) ("feb" . 2) ("mar" . 3)
118 ("apr" . 4) ("may" . 5) ("jun" . 6)
119 ("jul" . 7) ("aug" . 8) ("sep" . 9)
120 ("oct" . 10) ("nov" . 11) ("dec" . 12)))
121 (defvar parse-time-weekdays '(("sun" . 0) ("mon" . 1) ("tue" . 2)
122 ("wed" . 3) ("thu" . 4) ("fri" . 5) ("sat" . 6)))
123 (defvar parse-time-zoneinfo `(("z" 0) ("ut" 0) ("gmt" 0)
124 ("pst" ,(* -8 3600)) ("pdt" ,(* -7 3600) t)
125 ("mst" ,(* -7 3600)) ("mdt" ,(* -6 3600) t)
126 ("cst" ,(* -6 3600)) ("cdt" ,(* -5 3600) t)
127 ("est" ,(* -5 3600)) ("edt" ,(* -4 3600) t))
128 "(zoneinfo seconds-off daylight-savings-time-p)")
130 (defvar parse-time-rules
131 `(((6) parse-time-weekdays)
133 ((4) parse-time-months)
136 ,#'(lambda () (and (stringp elt)
139 (= (aref elt 5) ?:)))
141 ((8 7) parse-time-zoneinfo
142 ,#'(lambda () (car val))
143 ,#'(lambda () (cadr val)))
148 (or (= (aref elt 0) ?+) (= (aref elt 0) ?-))))
149 ,#'(lambda () (* 60 (+ (parse-integer elt 3 5)
150 (* 60 (parse-integer elt 1 3)))
151 (if (= (aref elt 0) ?-) -1 1))))
153 ,#'(lambda () (and (stringp elt)
156 (= (aref elt 7) ?-)))
159 ,#'(lambda () (and (stringp elt) (= (length elt) 5) (= (aref elt 2) ?:)))
160 [0 2] [3 5] ,#'(lambda () 0))
162 ,#'(lambda () (and (stringp elt)
164 (= (aref elt 1) ?:)))
165 [0 1] [2 4] ,#'(lambda () 0))
167 ,#'(lambda () (and (stringp elt)
169 (= (aref elt 1) ?:)))
171 ((5) (50 110) ,#'(lambda () (+ 1900 elt)))
172 ((5) (0 49) ,#'(lambda () (+ 2000 elt))))
173 "(slots predicate extractor...)")
175 (defun parse-time-string (string)
176 "Parse the time-string STRING into (SEC MIN HOUR DAY MON YEAR DOW DST TZ).
177 The values are identical to those of `decode-time', but any values that are
178 unknown are returned as nil."
179 (let ((time (list nil nil nil nil nil nil nil nil nil))
180 (temp (parse-time-tokenize (downcase string))))
182 (let ((elt (pop temp))
183 (rules parse-time-rules)
185 (while (and (not (null rules)) (not exit))
186 (let* ((rule (pop rules))
188 (predicate (pop rule))
190 (when (and (not (nth (car slots) time)) ;not already set
191 (setq val (cond ((and (consp predicate)
192 (not (eq (car predicate)
195 (<= (car predicate) elt)
196 (<= elt (cadr predicate))
200 (symbol-value predicate))))
201 ((funcall predicate)))))
204 (let ((new-val (and rule
205 (let ((this (pop rule)))
208 elt (aref this 0) (aref this 1))
210 (rplaca (nthcdr (pop slots) time) (or new-val val)))))))))
213 (provide 'parse-time)
215 ;;; parse-time.el ends here