summaryrefslogtreecommitdiff
path: root/lisp/calendar/parse-time.el
blob: 4a786da772670058e24da50c1d98210bdde4c218 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
;;; parse-time.el --- parsing time strings

;; Copyright (C) 1996, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
;;   Free Software Foundation, Inc.

;; Author: Erik Naggum <erik@naggum.no>
;; Keywords: util

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to
;; the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.

;;; Commentary:

;; With the introduction of the `encode-time', `decode-time', and
;; `format-time-string' functions, dealing with time became simpler in
;; Emacs.  However, parsing time strings is still largely a matter of
;; heuristics and no common interface has been designed.

;; `parse-time-string' parses a time in a string and returns a list of 9
;; values, just like `decode-time', where unspecified elements in the
;; string are returned as nil.  `encode-time' may be applied on these
;; values to obtain an internal time value.

;;; Code:

(eval-when-compile (require 'cl))	;and ah ain't kiddin' 'bout it

(defvar parse-time-syntax (make-vector 256 nil))
(defvar parse-time-digits (make-vector 256 nil))

;; Byte-compiler warnings
(defvar parse-time-elt)
(defvar parse-time-val)

(unless (aref parse-time-digits ?0)
  (loop for i from ?0 to ?9
    do (aset parse-time-digits i (- i ?0))))

(unless (aref parse-time-syntax ?0)
  (loop for i from ?0 to ?9
    do (aset parse-time-syntax i ?0))
  (loop for i from ?A to ?Z
    do (aset parse-time-syntax i ?A))
  (loop for i from ?a to ?z
    do (aset parse-time-syntax i ?a))
  (aset parse-time-syntax ?+ 1)
  (aset parse-time-syntax ?- -1)
  (aset parse-time-syntax ?: ?d)
  )

(defsubst digit-char-p (char)
  (aref parse-time-digits char))

(defsubst parse-time-string-chars (char)
  (aref parse-time-syntax char))

(put 'parse-error 'error-conditions '(parse-error error))
(put 'parse-error 'error-message "Parsing error")

(defsubst parse-integer (string &optional start end)
  "[CL] Parse and return the integer in STRING, or nil if none."
  (let ((integer 0)
	(digit 0)
	(index (or start 0))
	(end (or end (length string))))
    (when (< index end)
      (let ((sign (aref string index)))
	(if (or (eq sign ?+) (eq sign ?-))
	    (setq sign (parse-time-string-chars sign)
		  index (1+ index))
	  (setq sign 1))
	(while (and (< index end)
		    (setq digit (digit-char-p (aref string index))))
	  (setq integer (+ (* integer 10) digit)
		index (1+ index)))
	(if (/= index end)
	    (signal 'parse-error `("not an integer"
				   ,(substring string (or start 0) end)))
	  (* sign integer))))))

(defun parse-time-tokenize (string)
  "Tokenize STRING into substrings."
  (let ((start nil)
	(end (length string))
	(all-digits nil)
	(list ())
	(index 0)
	(c nil))
    (while (< index end)
      (while (and (< index end)		;skip invalid characters
		  (not (setq c (parse-time-string-chars (aref string index)))))
	(incf index))
      (setq start index all-digits (eq c ?0))
      (while (and (< (incf index) end)	;scan valid characters
		  (setq c (parse-time-string-chars (aref string index))))
	(setq all-digits (and all-digits (eq c ?0))))
      (if (<= index end)
	  (push (if all-digits (parse-integer string start index)
		  (substring string start index))
		list)))
    (nreverse list)))

(defvar parse-time-months '(("jan" . 1) ("feb" . 2) ("mar" . 3)
			    ("apr" . 4) ("may" . 5) ("jun" . 6)
			    ("jul" . 7) ("aug" . 8) ("sep" . 9)
			    ("oct" . 10) ("nov" . 11) ("dec" . 12)))
(defvar parse-time-weekdays '(("sun" . 0) ("mon" . 1) ("tue" . 2)
			      ("wed" . 3) ("thu" . 4) ("fri" . 5) ("sat" . 6)))
(defvar parse-time-zoneinfo `(("z" 0) ("ut" 0) ("gmt" 0)
			      ("pst" ,(* -8 3600)) ("pdt" ,(* -7 3600) t)
			      ("mst" ,(* -7 3600)) ("mdt" ,(* -6 3600) t)
			      ("cst" ,(* -6 3600)) ("cdt" ,(* -5 3600) t)
			      ("est" ,(* -5 3600)) ("edt" ,(* -4 3600) t))
  "(zoneinfo seconds-off daylight-savings-time-p)")

(defvar parse-time-rules
  `(((6) parse-time-weekdays)
    ((3) (1 31))
    ((4) parse-time-months)
    ((5) (100 4038))
    ((2 1 0)
     ,#'(lambda () (and (stringp parse-time-elt)
			(= (length parse-time-elt) 8)
			(= (aref parse-time-elt 2) ?:)
			(= (aref parse-time-elt 5) ?:)))
     [0 2] [3 5] [6 8])
    ((8 7) parse-time-zoneinfo
     ,#'(lambda () (car parse-time-val))
     ,#'(lambda () (cadr parse-time-val)))
    ((8)
     ,#'(lambda ()
	  (and (stringp parse-time-elt)
	       (= 5 (length parse-time-elt))
	       (or (= (aref parse-time-elt 0) ?+)
		   (= (aref parse-time-elt 0) ?-))))
     ,#'(lambda () (* 60 (+ (parse-integer parse-time-elt 3 5)
			    (* 60 (parse-integer parse-time-elt 1 3)))
		      (if (= (aref parse-time-elt 0) ?-) -1 1))))
    ((5 4 3)
     ,#'(lambda () (and (stringp parse-time-elt)
			(= (length parse-time-elt) 10)
			(= (aref parse-time-elt 4) ?-)
			(= (aref parse-time-elt 7) ?-)))
     [0 4] [5 7] [8 10])
    ((2 1 0)
     ,#'(lambda () (and (stringp parse-time-elt)
			(= (length parse-time-elt) 5)
			(= (aref parse-time-elt 2) ?:)))
     [0 2] [3 5] ,#'(lambda () 0))
    ((2 1 0)
     ,#'(lambda () (and (stringp parse-time-elt)
			(= (length parse-time-elt) 4)
			(= (aref parse-time-elt 1) ?:)))
     [0 1] [2 4] ,#'(lambda () 0))
    ((2 1 0)
     ,#'(lambda () (and (stringp parse-time-elt)
			(= (length parse-time-elt) 7)
			(= (aref parse-time-elt 1) ?:)))
     [0 1] [2 4] [5 7])
    ((5) (50 110) ,#'(lambda () (+ 1900 parse-time-elt)))
    ((5) (0 49) ,#'(lambda () (+ 2000 parse-time-elt))))
  "(slots predicate extractor...)")

;;;###autoload
(defun parse-time-string (string)
  "Parse the time-string STRING into (SEC MIN HOUR DAY MON YEAR DOW DST TZ).
The values are identical to those of `decode-time', but any values that are
unknown are returned as nil."
  (let ((time (list nil nil nil nil nil nil nil nil nil))
	(temp (parse-time-tokenize (downcase string))))
    (while temp
      (let ((parse-time-elt (pop temp))
	    (rules parse-time-rules)
	    (exit nil))
	(while (and (not (null rules)) (not exit))
	  (let* ((rule (pop rules))
		 (slots (pop rule))
		 (predicate (pop rule))
		 (parse-time-val))
	    (when (and (not (nth (car slots) time)) ;not already set
		       (setq parse-time-val (cond ((and (consp predicate)
					     (not (eq (car predicate)
						      'lambda)))
					(and (numberp parse-time-elt)
					     (<= (car predicate) parse-time-elt)
					     (<= parse-time-elt (cadr predicate))
					     parse-time-elt))
				       ((symbolp predicate)
					(cdr (assoc parse-time-elt
						    (symbol-value predicate))))
				       ((funcall predicate)))))
	      (setq exit t)
	      (while slots
		(let ((new-val (and rule
				    (let ((this (pop rule)))
				      (if (vectorp this)
					  (parse-integer
					   parse-time-elt
					   (aref this 0) (aref this 1))
					(funcall this))))))
		  (rplaca (nthcdr (pop slots) time)
			  (or new-val parse-time-val)))))))))
    time))

(provide 'parse-time)

;;; arch-tag: 07066094-45a8-4c68-b307-86195e2c1103
;;; parse-time.el ends here