1 ;;; time-date.el --- Date and time handling functions
3 ;; Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
4 ;; 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
6 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
7 ;; Masanobu Umeda <umerin@mse.kyutech.ac.jp>
8 ;; Keywords: mail news util
10 ;; This file is part of GNU Emacs.
12 ;; GNU Emacs is free software: you can redistribute it and/or modify
13 ;; it under the terms of the GNU General Public License as published by
14 ;; the Free Software Foundation, either version 3 of the License, or
15 ;; (at your option) any later version.
17 ;; GNU Emacs is distributed in the hope that it will be useful,
18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 ;; GNU General Public License for more details.
22 ;; You should have received a copy of the GNU General Public License
23 ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
27 ;; Time values come in three formats. The oldest format is a cons
28 ;; cell of the form (HIGH . LOW). This format is obsolete, but still
29 ;; supported. The two other formats are the lists (HIGH LOW) and
30 ;; (HIGH LOW MICRO). The first two formats specify HIGH * 2^16 + LOW
31 ;; seconds; the third format specifies HIGH * 2^16 + LOW + MICRO /
32 ;; 1000000 seconds. We should have 0 <= MICRO < 1000000 and 0 <= LOW
33 ;; < 2^16. If the time value represents a point in time, then HIGH is
34 ;; nonnegative. If the time value is a time difference, then HIGH can
35 ;; be negative as well. The macro `with-decoded-time-value' and the
36 ;; function `encode-time-value' make it easier to deal with these
37 ;; three formats. See `time-subtract' for an example of how to use
42 (defmacro with-decoded-time-value (varlist &rest body)
43 "Decode a time value and bind it according to VARLIST, then eval BODY.
45 The value of the last form in BODY is returned.
47 Each element of the list VARLIST is a list of the form
48 \(HIGH-SYMBOL LOW-SYMBOL MICRO-SYMBOL [TYPE-SYMBOL] TIME-VALUE).
49 The time value TIME-VALUE is decoded and the result it bound to
50 the symbols HIGH-SYMBOL, LOW-SYMBOL and MICRO-SYMBOL.
52 The optional TYPE-SYMBOL is bound to the type of the time value.
53 Type 0 is the cons cell (HIGH . LOW), type 1 is the list (HIGH
54 LOW), and type 2 is the list (HIGH LOW MICRO)."
56 (debug ((&rest (symbolp symbolp symbolp &or [symbolp form] form))
59 (let* ((elt (pop varlist))
63 (type (unless (eq (length elt) 1)
65 (time-value (car elt))
66 (gensym (make-symbol "time")))
67 `(let* ,(append `((,gensym ,time-value)
73 (setq ,low (pop ,gensym))
75 ,(append `(setq ,micro (car ,gensym))
76 (when type `(,type 2)))
77 ,(append `(setq ,micro 0)
78 (when type `(,type 1)))))
79 ,(append `(setq ,low ,gensym ,micro 0)
80 (when type `(,type 0))))
81 (with-decoded-time-value ,varlist ,@body)))
84 (defun encode-time-value (high low micro type)
85 "Encode HIGH, LOW, and MICRO into a time value of type TYPE.
86 Type 0 is the cons cell (HIGH . LOW), type 1 is the list (HIGH LOW),
87 and type 2 is the list (HIGH LOW MICRO)."
89 ((eq type 0) (cons high low))
90 ((eq type 1) (list high low))
91 ((eq type 2) (list high low micro))))
93 (autoload 'parse-time-string "parse-time")
94 (autoload 'timezone-make-date-arpa-standard "timezone")
97 ;; `parse-time-string' isn't sufficiently general or robust. It fails
98 ;; to grok some of the formats that timezone does (e.g. dodgy
99 ;; post-2000 stuff from some Elms) and either fails or returns bogus
100 ;; values. timezone-make-date-arpa-standard should help.
101 (defun date-to-time (date)
102 "Parse a string DATE that represents a date-time and return a time value.
103 If DATE lacks timezone information, GMT is assumed."
105 (apply 'encode-time (parse-time-string date))
106 (error (condition-case ()
109 (timezone-make-date-arpa-standard date)))
110 (error (error "Invalid date: %s" date))))))
112 ;; Bit of a mess. Emacs has float-time since at least 21.1.
113 ;; This file is synced to Gnus, and XEmacs packages may have been written
114 ;; using time-to-seconds from the Gnus library.
115 ;;;###autoload(if (or (featurep 'emacs)
116 ;;;###autoload (and (fboundp 'float-time)
117 ;;;###autoload (subrp (symbol-function 'float-time))))
118 ;;;###autoload (progn
119 ;;;###autoload (defalias 'time-to-seconds 'float-time)
120 ;;;###autoload (make-obsolete 'time-to-seconds 'float-time "21.1"))
121 ;;;###autoload (autoload 'time-to-seconds "time-date"))
124 (or (featurep 'emacs)
125 (and (fboundp 'float-time)
126 (subrp (symbol-function 'float-time)))
127 (defun time-to-seconds (time)
128 "Convert time value TIME to a floating point number."
129 (with-decoded-time-value ((high low micro time))
130 (+ (* 1.0 high 65536)
132 (/ micro 1000000.0))))))
135 (defun seconds-to-time (seconds)
136 "Convert SECONDS (a floating point number) to a time value."
137 (list (floor seconds 65536)
138 (floor (mod seconds 65536))
139 (floor (* (- seconds (ffloor seconds)) 1000000))))
142 (defun time-less-p (t1 t2)
143 "Return non-nil if time value T1 is earlier than time value T2."
144 (with-decoded-time-value ((high1 low1 micro1 t1)
145 (high2 low2 micro2 t2))
150 (< micro1 micro2)))))))
153 (defun days-to-time (days)
154 "Convert DAYS into a time value."
155 (let* ((seconds (* 1.0 days 60 60 24))
156 (high (condition-case nil (floor (/ seconds 65536))
157 (range-error most-positive-fixnum))))
158 (list high (condition-case nil (floor (- seconds (* 1.0 high 65536)))
159 (range-error 65535)))))
162 (defun time-since (time)
163 "Return the time elapsed since TIME.
164 TIME should be either a time value or a date-time string."
166 ;; Convert date strings to internal time.
167 (setq time (date-to-time time)))
168 (time-subtract (current-time) time))
171 (defalias 'subtract-time 'time-subtract)
174 (defun time-subtract (t1 t2)
175 "Subtract two time values, T1 minus T2.
176 Return the difference in the format of a time value."
177 (with-decoded-time-value ((high low micro type t1)
178 (high2 low2 micro2 type2 t2))
179 (setq high (- high high2)
181 micro (- micro micro2)
182 type (max type type2))
185 micro (+ micro 1000000)))
189 (encode-time-value high low micro type)))
192 (defun time-add (t1 t2)
193 "Add two time values T1 and T2. One should represent a time difference."
194 (with-decoded-time-value ((high low micro type t1)
195 (high2 low2 micro2 type2 t2))
196 (setq high (+ high high2)
198 micro (+ micro micro2)
199 type (max type type2))
200 (when (>= micro 1000000)
202 micro (- micro 1000000)))
206 (encode-time-value high low micro type)))
209 (defun date-to-day (date)
210 "Return the number of days between year 1 and DATE.
211 DATE should be a date-time string."
212 (time-to-days (date-to-time date)))
215 (defun days-between (date1 date2)
216 "Return the number of days between DATE1 and DATE2.
217 DATE1 and DATE2 should be date-time strings."
218 (- (date-to-day date1) (date-to-day date2)))
221 (defun date-leap-year-p (year)
222 "Return t if YEAR is a leap year."
223 (or (and (zerop (% year 4))
224 (not (zerop (% year 100))))
225 (zerop (% year 400))))
228 (defun time-to-day-in-year (time)
229 "Return the day number within the year corresponding to TIME."
230 (let* ((tim (decode-time time))
234 (day-of-year (+ day (* 31 (1- month)))))
236 (setq day-of-year (- day-of-year (/ (+ 23 (* 4 month)) 10)))
237 (when (date-leap-year-p year)
238 (setq day-of-year (1+ day-of-year))))
242 (defun time-to-days (time)
243 "The number of days between the Gregorian date 0001-12-31bce and TIME.
244 TIME should be a time value.
245 The Gregorian date Sunday, December 31, 1bce is imaginary."
246 (let* ((tim (decode-time time))
250 (+ (time-to-day-in-year time) ; Days this year
251 (* 365 (1- year)) ; + Days in prior years
252 (/ (1- year) 4) ; + Julian leap years
253 (- (/ (1- year) 100)) ; - century years
254 (/ (1- year) 400)))) ; + Gregorian leap years
256 (defun time-to-number-of-days (time)
257 "Return the number of days represented by TIME.
258 Returns a floating point number."
259 (/ (funcall (eval-when-compile
260 (if (or (featurep 'emacs)
261 (and (fboundp 'float-time)
262 (subrp (symbol-function 'float-time))))
264 'time-to-seconds)) time) (* 60 60 24)))
267 (defun safe-date-to-time (date)
268 "Parse a string DATE that represents a date-time and return a time value.
269 If DATE is malformed, return a time value of zeros."
276 (defun format-seconds (string seconds)
277 "Use format control STRING to format the number SECONDS.
278 The valid format specifiers are:
279 %y is the number of (365-day) years.
280 %d is the number of days.
281 %h is the number of hours.
282 %m is the number of minutes.
283 %s is the number of seconds.
284 %z is a non-printing control flag (see below).
285 %% is a literal \"%\".
287 Upper-case specifiers are followed by the unit-name (e.g. \"years\").
288 Lower-case specifiers return only the unit.
290 \"%\" may be followed by a number specifying a width, with an
291 optional leading \".\" for zero-padding. For example, \"%.3Y\" will
292 return something of the form \"001 year\".
294 The \"%z\" specifier does not print anything. When it is used, specifiers
295 must be given in order of decreasing size. To the left of \"%z\", nothing
296 is output until the first non-zero unit is encountered.
298 This function does not work for SECONDS greater than `most-positive-fixnum'."
300 (units '(("y" "year" 31536000)
307 spec match usedunits zeroflag larger prev name unit num zeropos)
308 (while (string-match "%\\.?[0-9]*\\(.\\)" string start)
309 (setq start (match-end 0)
310 spec (match-string 1 string))
311 (unless (string-equal spec "%")
312 ;; `assoc-string' is not available in XEmacs. So when compiling
313 ;; Gnus (`time-date.el' is part of Gnus) with XEmacs, we get
314 ;; a warning here. But `format-seconds' is not used anywhere in
315 ;; Gnus so it's not a real problem. --rsteib
316 (or (setq match (assoc-string spec units t))
317 (error "Bad format specifier: `%s'" spec))
318 (if (assoc-string spec usedunits t)
319 (error "Multiple instances of specifier: `%s'" spec))
320 (if (string-equal (car match) "z")
323 (setq unit (nth 2 match)
324 larger (and prev (> unit prev))
326 (push match usedunits)))
328 (error "Units are not in decreasing order of size"))
333 (when (string-match (format "%%\\(\\.?[0-9]+\\)?\\(%s\\)" spec) string)
334 (if (string-equal spec "z") ; must be last in units
336 (replace-regexp-in-string
338 (substring string (min (or zeropos (match-end 0))
339 (match-beginning 0)))))
340 ;; Cf article-make-date-line in gnus-art.
341 (setq num (floor seconds unit)
342 seconds (- seconds (* num unit)))
343 ;; Start position of the first non-zero unit.
345 (setq zeropos (unless (zerop num) (match-beginning 0))))
348 (format (concat "%" (match-string 1 string) "d%s") num
349 (if (string-equal (match-string 2 string) spec)
350 "" ; lower-case, no unit-name
352 (if (= num 1) "" "s"))))
354 (replace-regexp-in-string "%%" "%" string))
359 ;;; time-date.el ends here