1 ;;; time-date.el --- Date and time handling functions
3 ;; Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
4 ;; 2007, 2008 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 This format is obsolete, but still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 (defun date-to-time (date)
98 "Parse a string DATE that represents a date-time and return a time value."
102 ;; `parse-time-string' isn't sufficiently general or
103 ;; robust. It fails to grok some of the formats that
104 ;; timezone does (e.g. dodgy post-2000 stuff from some
105 ;; Elms) and either fails or returns bogus values. Lars
106 ;; reverted this change, but that loses non-trivially
107 ;; often for me. -- fx
108 (timezone-make-date-arpa-standard date
)))
109 (error (error "Invalid date: %s" date
))))
112 (defun time-to-seconds (time)
113 "Convert time value TIME to a floating point number.
114 You can use `float-time' instead."
115 (with-decoded-time-value ((high low micro time
))
116 (+ (* 1.0 high
65536)
118 (/ micro
1000000.0))))
121 (defun seconds-to-time (seconds)
122 "Convert SECONDS (a floating point number) to a time value."
123 (list (floor seconds
65536)
124 (floor (mod seconds
65536))
125 (floor (* (- seconds
(ffloor seconds
)) 1000000))))
128 (defun time-less-p (t1 t2
)
129 "Say whether time value T1 is less than time value T2."
130 (with-decoded-time-value ((high1 low1 micro1 t1
)
131 (high2 low2 micro2 t2
))
136 (< micro1 micro2
)))))))
139 (defun days-to-time (days)
140 "Convert DAYS into a time value."
141 (let* ((seconds (* 1.0 days
60 60 24))
142 (high (condition-case nil
(floor (/ seconds
65536))
143 (range-error most-positive-fixnum
))))
144 (list high
(condition-case nil
(floor (- seconds
(* 1.0 high
65536)))
145 (range-error 65535)))))
148 (defun time-since (time)
149 "Return the time elapsed since TIME.
150 TIME should be either a time value or a date-time string."
152 ;; Convert date strings to internal time.
153 (setq time
(date-to-time time
)))
154 (time-subtract (current-time) time
))
157 (defalias 'subtract-time
'time-subtract
)
160 (defun time-subtract (t1 t2
)
161 "Subtract two time values, T1 minus T2.
162 Return the difference in the format of a time value."
163 (with-decoded-time-value ((high low micro type t1
)
164 (high2 low2 micro2 type2 t2
))
165 (setq high
(- high high2
)
167 micro
(- micro micro2
)
168 type
(max type type2
))
171 micro
(+ micro
1000000)))
175 (encode-time-value high low micro type
)))
178 (defun time-add (t1 t2
)
179 "Add two time values T1 and T2. One should represent a time difference."
180 (with-decoded-time-value ((high low micro type t1
)
181 (high2 low2 micro2 type2 t2
))
182 (setq high
(+ high high2
)
184 micro
(+ micro micro2
)
185 type
(max type type2
))
186 (when (>= micro
1000000)
188 micro
(- micro
1000000)))
192 (encode-time-value high low micro type
)))
195 (defun date-to-day (date)
196 "Return the number of days between year 1 and DATE.
197 DATE should be a date-time string."
198 (time-to-days (date-to-time date
)))
201 (defun days-between (date1 date2
)
202 "Return the number of days between DATE1 and DATE2.
203 DATE1 and DATE2 should be date-time strings."
204 (- (date-to-day date1
) (date-to-day date2
)))
207 (defun date-leap-year-p (year)
208 "Return t if YEAR is a leap year."
209 (or (and (zerop (% year
4))
210 (not (zerop (% year
100))))
211 (zerop (% year
400))))
214 (defun time-to-day-in-year (time)
215 "Return the day number within the year corresponding to TIME."
216 (let* ((tim (decode-time time
))
220 (day-of-year (+ day
(* 31 (1- month
)))))
222 (setq day-of-year
(- day-of-year
(/ (+ 23 (* 4 month
)) 10)))
223 (when (date-leap-year-p year
)
224 (setq day-of-year
(1+ day-of-year
))))
228 (defun time-to-days (time)
229 "The number of days between the Gregorian date 0001-12-31bce and TIME.
230 TIME should be a time value.
231 The Gregorian date Sunday, December 31, 1bce is imaginary."
232 (let* ((tim (decode-time time
))
236 (+ (time-to-day-in-year time
) ; Days this year
237 (* 365 (1- year
)) ; + Days in prior years
238 (/ (1- year
) 4) ; + Julian leap years
239 (- (/ (1- year
) 100)) ; - century years
240 (/ (1- year
) 400)))) ; + Gregorian leap years
242 (defun time-to-number-of-days (time)
243 "Return the number of days represented by TIME.
244 The number of days will be returned as a floating point number."
245 (/ (time-to-seconds time
) (* 60 60 24)))
248 (defun safe-date-to-time (date)
249 "Parse a string DATE that represents a date-time and return a time value.
250 If DATE is malformed, return a time value of zeros."
257 (defun format-seconds (string seconds
)
258 "Use format control STRING to format the number SECONDS.
259 The valid format specifiers are:
260 %y is the number of (365-day) years.
261 %d is the number of days.
262 %h is the number of hours.
263 %m is the number of minutes.
264 %s is the number of seconds.
265 %z is a non-printing control flag (see below).
266 %% is a literal \"%\".
268 Upper-case specifiers are followed by the unit-name (e.g. \"years\").
269 Lower-case specifiers return only the unit.
271 \"%\" may be followed by a number specifying a width, with an
272 optional leading \".\" for zero-padding. For example, \"%.3Y\" will
273 return something of the form \"001 year\".
275 The \"%z\" specifier does not print anything. When it is used, specifiers
276 must be given in order of decreasing size. To the left of \"%z\", nothing
277 is output until the first non-zero unit is encountered.
279 This function does not work for SECONDS greater than `most-positive-fixnum'."
281 (units '(("y" "year" 31536000)
288 spec match usedunits zeroflag larger prev name unit num zeropos
)
289 (while (string-match "%\\.?[0-9]*\\(.\\)" string start
)
290 (setq start
(match-end 0)
291 spec
(match-string 1 string
))
292 (unless (string-equal spec
"%")
293 (or (setq match
(assoc-string spec units t
))
294 (error "Bad format specifier: `%s'" spec
))
295 (if (assoc-string spec usedunits t
)
296 (error "Multiple instances of specifier: `%s'" spec
))
297 (if (string-equal (car match
) "z")
300 (setq unit
(nth 2 match
)
301 larger
(and prev
(> unit prev
))
303 (push match usedunits
)))
305 (error "Units are not in decreasing order of size"))
310 (when (string-match (format "%%\\(\\.?[0-9]+\\)?\\(%s\\)" spec
) string
)
311 (if (string-equal spec
"z") ; must be last in units
313 (replace-regexp-in-string
315 (substring string
(min (or zeropos
(match-end 0))
316 (match-beginning 0)))))
317 ;; Cf article-make-date-line in gnus-art.
318 (setq num
(floor seconds unit
)
319 seconds
(- seconds
(* num unit
)))
320 ;; Start position of the first non-zero unit.
322 (setq zeropos
(unless (zerop num
) (match-beginning 0))))
325 (format (concat "%" (match-string 1 string
) "d%s") num
326 (if (string-equal (match-string 2 string
) spec
)
327 "" ; lower-case, no unit-name
329 (if (= num
1) "" "s"))))
331 (replace-regexp-in-string "%%" "%" string
))
336 ;; arch-tag: addcf07b-b20a-465b-af72-550b8ac5190f
337 ;;; time-date.el ends here