1 ;;; srfi-19.scm --- Time/Date Library
3 ;; Copyright (C) 2001, 2002, 2003, 2005, 2006 Free Software Foundation, Inc.
5 ;; This library is free software; you can redistribute it and/or
6 ;; modify it under the terms of the GNU Lesser General Public
7 ;; License as published by the Free Software Foundation; either
8 ;; version 2.1 of the License, or (at your option) any later version.
10 ;; This library is distributed in the hope that it will be useful,
11 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
12 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 ;; Lesser General Public License for more details.
15 ;; You should have received a copy of the GNU Lesser General Public
16 ;; License along with this library; if not, write to the Free Software
17 ;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 ;;; Author: Rob Browning <rlb@cs.utexas.edu>
20 ;;; Originally from SRFI reference implementation by Will Fitzgerald.
24 ;; This module is fully documented in the Guile Reference Manual.
28 ;; FIXME: I haven't checked a decent amount of this code for potential
29 ;; performance improvements, but I suspect that there may be some
30 ;; substantial ones to be realized, esp. in the later "parsing" half
31 ;; of the file, by rewriting the code with use of more Guile native
32 ;; functions that do more work in a "chunk".
34 ;; FIXME: mkoeppe: Time zones are treated a little simplistic in
35 ;; SRFI-19; they are only a numeric offset. Thus, printing time zones
36 ;; (PRIV:LOCALE-PRINT-TIME-ZONE) can't be implemented sensibly. The
37 ;; functions taking an optional TZ-OFFSET should be extended to take a
38 ;; symbolic time-zone (like "CET"); this string should be stored in
39 ;; the DATE structure.
41 (define-module (srfi srfi-19)
42 :use-module (srfi srfi-6)
43 :use-module (srfi srfi-8)
44 :use-module (srfi srfi-9))
47 ;; Prevent `export' from re-exporting core bindings. This behaviour
48 ;; of `export' is deprecated and will disappear in one of the next
50 (define current-time #f))
59 ;; Current time and clock resolution
62 current-modified-julian-day
65 ;; Time object and accessors
75 ;; Time comparison procedures
81 ;; Time arithmetic procedures
88 ;; Date object and accessors
102 ;; Time/Date/Julian Day/Modified Julian Day converters
104 date->modified-julian-day
109 julian-day->time-monotonic
112 modified-julian-day->date
113 modified-julian-day->time-monotonic
114 modified-julian-day->time-tai
115 modified-julian-day->time-utc
117 time-monotonic->time-tai
118 time-monotonic->time-tai!
119 time-monotonic->time-utc
120 time-monotonic->time-utc!
123 time-tai->modified-julian-day
124 time-tai->time-monotonic
125 time-tai->time-monotonic!
130 time-utc->modified-julian-day
131 time-utc->time-monotonic
132 time-utc->time-monotonic!
135 ;; Date to string/string to date converters.
139 (cond-expand-provide (current-module) '(srfi-19))
141 (define time-tai 'time-tai)
142 (define time-utc 'time-utc)
143 (define time-monotonic 'time-monotonic)
144 (define time-thread 'time-thread)
145 (define time-process 'time-process)
146 (define time-duration 'time-duration)
148 ;; FIXME: do we want to add gc time?
149 ;; (define time-gc 'time-gc)
151 ;;-- LOCALE dependent constants
153 (define priv:locale-number-separator ".")
155 (define priv:locale-abbr-weekday-vector
156 (vector "Sun" "Mon" "Tue" "Wed" "Thu" "Fri" "Sat"))
158 (define priv:locale-long-weekday-vector
160 "Sunday" "Monday" "Tuesday" "Wednesday" "Thursday" "Friday" "Saturday"))
162 ;; note empty string in 0th place.
163 (define priv:locale-abbr-month-vector
178 (define priv:locale-long-month-vector
193 (define priv:locale-pm "PM")
194 (define priv:locale-am "AM")
197 (define priv:locale-date-time-format "~a ~b ~d ~H:~M:~S~z ~Y")
198 (define priv:locale-short-date-format "~m/~d/~y")
199 (define priv:locale-time-format "~H:~M:~S")
200 (define priv:iso-8601-date-time-format "~Y-~m-~dT~H:~M:~S~z")
202 ;;-- Miscellaneous Constants.
203 ;;-- only the priv:tai-epoch-in-jd might need changing if
204 ;; a different epoch is used.
206 (define priv:nano 1000000000) ; nanoseconds in a second
207 (define priv:sid 86400) ; seconds in a day
208 (define priv:sihd 43200) ; seconds in a half day
209 (define priv:tai-epoch-in-jd 4881175/2) ; julian day number for 'the epoch'
211 ;; FIXME: should this be something other than misc-error?
212 (define (priv:time-error caller type value)
214 (throw 'misc-error caller "TIME-ERROR type ~A: ~S" (list type value) #f)
215 (throw 'misc-error caller "TIME-ERROR type ~A" (list type) #f)))
217 ;; A table of leap seconds
218 ;; See ftp://maia.usno.navy.mil/ser7/tai-utc.dat
219 ;; and update as necessary.
220 ;; this procedures reads the file in the abover
221 ;; format and creates the leap second table
222 ;; it also calls the almost standard, but not R5 procedures read-line
223 ;; & open-input-string
224 ;; ie (set! priv:leap-second-table (priv:read-tai-utc-date "tai-utc.dat"))
226 (define (priv:read-tai-utc-data filename)
227 (define (convert-jd jd)
228 (* (- (inexact->exact jd) priv:tai-epoch-in-jd) priv:sid))
229 (define (convert-sec sec)
230 (inexact->exact sec))
231 (let ((port (open-input-file filename))
233 (let loop ((line (read-line port)))
234 (if (not (eq? line eof))
236 (let* ((data (read (open-input-string
237 (string-append "(" line ")"))))
239 (jd (cadddr (cdr data)))
240 (secs (cadddr (cdddr data))))
243 (cons (convert-jd jd) (convert-sec secs))
245 (loop (read-line port))))))
248 ;; each entry is (tai seconds since epoch . # seconds to subtract for utc)
249 ;; note they go higher to lower, and end in 1972.
250 (define priv:leap-second-table
276 (define (read-leap-second-table filename)
277 (set! priv:leap-second-table (priv:read-tai-utc-data filename))
281 (define (priv:leap-second-delta utc-seconds)
282 (letrec ((lsd (lambda (table)
283 (cond ((>= utc-seconds (caar table))
285 (else (lsd (cdr table)))))))
286 (if (< utc-seconds (* (- 1972 1970) 365 priv:sid)) 0
287 (lsd priv:leap-second-table))))
290 ;;; the TIME structure; creates the accessors, too.
292 (define-record-type time
293 (make-time-unnormalized type nanosecond second)
295 (type time-type set-time-type!)
296 (nanosecond time-nanosecond set-time-nanosecond!)
297 (second time-second set-time-second!))
299 (define (copy-time time)
300 (make-time (time-type time) (time-nanosecond time) (time-second time)))
302 (define (priv:split-real r)
304 (values (inexact->exact r) 0)
305 (let ((l (truncate r)))
306 (values (inexact->exact l) (- r l)))))
308 (define (priv:time-normalize! t)
309 (if (>= (abs (time-nanosecond t)) 1000000000)
311 (priv:split-real (time-nanosecond t))
312 (set-time-second! t (+ (time-second t)
313 (quotient int 1000000000)))
314 (set-time-nanosecond! t (+ (remainder int 1000000000)
316 (if (and (positive? (time-second t))
317 (negative? (time-nanosecond t)))
319 (set-time-second! t (- (time-second t) 1))
320 (set-time-nanosecond! t (+ 1000000000 (time-nanosecond t))))
321 (if (and (negative? (time-second t))
322 (positive? (time-nanosecond t)))
324 (set-time-second! t (+ (time-second t) 1))
325 (set-time-nanosecond! t (+ 1000000000 (time-nanosecond t))))))
328 (define (make-time type nanosecond second)
329 (priv:time-normalize! (make-time-unnormalized type nanosecond second)))
332 ;; FIXME: finish this and publish it?
333 (define (date->broken-down-time date)
334 (let ((result (mktime 0)))
335 ;; FIXME: What should we do about leap-seconds which may overflow
337 (set-tm:sec result (date-second date))
338 (set-tm:min result (date-minute date))
339 (set-tm:hour result (date-hour date))
340 ;; FIXME: SRFI day ranges from 0-31. (not compatible with set-tm:mday).
341 (set-tm:mday result (date-day date))
342 (set-tm:month result (- (date-month date) 1))
343 ;; FIXME: need to signal error on range violation.
344 (set-tm:year result (+ 1900 (date-year date)))
345 (set-tm:isdst result -1)
346 (set-tm:gmtoff result (- (date-zone-offset date)))
351 ;;; specific time getters.
353 (define (priv:current-time-utc)
354 ;; Resolution is microseconds.
355 (let ((tod (gettimeofday)))
356 (make-time time-utc (* (cdr tod) 1000) (car tod))))
358 (define (priv:current-time-tai)
359 ;; Resolution is microseconds.
360 (let* ((tod (gettimeofday))
365 (+ (car tod) (priv:leap-second-delta sec)))))
367 ;;(define (priv:current-time-ms-time time-type proc)
368 ;; (let ((current-ms (proc)))
369 ;; (make-time time-type
370 ;; (quotient current-ms 10000)
371 ;; (* (remainder current-ms 1000) 10000))))
373 ;; -- we define it to be the same as TAI.
374 ;; A different implemation of current-time-montonic
375 ;; will require rewriting all of the time-monotonic converters,
378 (define (priv:current-time-monotonic)
379 ;; Resolution is microseconds.
380 (priv:current-time-tai))
382 (define (priv:current-time-thread)
383 (priv:time-error 'current-time 'unsupported-clock-type 'time-thread))
385 (define priv:ns-per-guile-tick (/ 1000000000 internal-time-units-per-second))
387 (define (priv:current-time-process)
388 (let ((run-time (get-internal-run-time)))
391 (quotient run-time internal-time-units-per-second)
392 (* (remainder run-time internal-time-units-per-second)
393 priv:ns-per-guile-tick))))
395 (define (priv:current-time-process)
396 (let ((run-time (get-internal-run-time)))
399 (* (remainder run-time internal-time-units-per-second)
400 priv:ns-per-guile-tick)
401 (quotient run-time internal-time-units-per-second))))
403 ;;(define (priv:current-time-gc)
404 ;; (priv:current-time-ms-time time-gc current-gc-milliseconds))
406 (define (current-time . clock-type)
407 (let ((clock-type (if (null? clock-type) time-utc (car clock-type))))
409 ((eq? clock-type time-tai) (priv:current-time-tai))
410 ((eq? clock-type time-utc) (priv:current-time-utc))
411 ((eq? clock-type time-monotonic) (priv:current-time-monotonic))
412 ((eq? clock-type time-thread) (priv:current-time-thread))
413 ((eq? clock-type time-process) (priv:current-time-process))
414 ;; ((eq? clock-type time-gc) (priv:current-time-gc))
415 (else (priv:time-error 'current-time 'invalid-clock-type clock-type)))))
417 ;; -- Time Resolution
418 ;; This is the resolution of the clock in nanoseconds.
419 ;; This will be implementation specific.
421 (define (time-resolution . clock-type)
422 (let ((clock-type (if (null? clock-type) time-utc (car clock-type))))
426 ((time-monotonic) 1000)
427 ((time-process) priv:ns-per-guile-tick)
428 ;; ((eq? clock-type time-thread) 1000)
429 ;; ((eq? clock-type time-gc) 10000)
430 (else (priv:time-error 'time-resolution 'invalid-clock-type clock-type)))))
432 ;; -- Time comparisons
434 (define (time=? t1 t2)
435 ;; Arrange tests for speed and presume that t1 and t2 are actually times.
436 ;; also presume it will be rare to check two times of different types.
437 (and (= (time-second t1) (time-second t2))
438 (= (time-nanosecond t1) (time-nanosecond t2))
439 (eq? (time-type t1) (time-type t2))))
441 (define (time>? t1 t2)
442 (or (> (time-second t1) (time-second t2))
443 (and (= (time-second t1) (time-second t2))
444 (> (time-nanosecond t1) (time-nanosecond t2)))))
446 (define (time<? t1 t2)
447 (or (< (time-second t1) (time-second t2))
448 (and (= (time-second t1) (time-second t2))
449 (< (time-nanosecond t1) (time-nanosecond t2)))))
451 (define (time>=? t1 t2)
452 (or (> (time-second t1) (time-second t2))
453 (and (= (time-second t1) (time-second t2))
454 (>= (time-nanosecond t1) (time-nanosecond t2)))))
456 (define (time<=? t1 t2)
457 (or (< (time-second t1) (time-second t2))
458 (and (= (time-second t1) (time-second t2))
459 (<= (time-nanosecond t1) (time-nanosecond t2)))))
461 ;; -- Time arithmetic
463 (define (time-difference! time1 time2)
464 (let ((sec-diff (- (time-second time1) (time-second time2)))
465 (nsec-diff (- (time-nanosecond time1) (time-nanosecond time2))))
466 (set-time-type! time1 time-duration)
467 (set-time-second! time1 sec-diff)
468 (set-time-nanosecond! time1 nsec-diff)
469 (priv:time-normalize! time1)))
471 (define (time-difference time1 time2)
472 (let ((result (copy-time time1)))
473 (time-difference! result time2)))
475 (define (add-duration! t duration)
476 (if (not (eq? (time-type duration) time-duration))
477 (priv:time-error 'add-duration 'not-duration duration)
478 (let ((sec-plus (+ (time-second t) (time-second duration)))
479 (nsec-plus (+ (time-nanosecond t) (time-nanosecond duration))))
480 (set-time-second! t sec-plus)
481 (set-time-nanosecond! t nsec-plus)
482 (priv:time-normalize! t))))
484 (define (add-duration t duration)
485 (let ((result (copy-time t)))
486 (add-duration! result duration)))
488 (define (subtract-duration! t duration)
489 (if (not (eq? (time-type duration) time-duration))
490 (priv:time-error 'add-duration 'not-duration duration)
491 (let ((sec-minus (- (time-second t) (time-second duration)))
492 (nsec-minus (- (time-nanosecond t) (time-nanosecond duration))))
493 (set-time-second! t sec-minus)
494 (set-time-nanosecond! t nsec-minus)
495 (priv:time-normalize! t))))
497 (define (subtract-duration time1 duration)
498 (let ((result (copy-time time1)))
499 (subtract-duration! result duration)))
501 ;; -- Converters between types.
503 (define (priv:time-tai->time-utc! time-in time-out caller)
504 (if (not (eq? (time-type time-in) time-tai))
505 (priv:time-error caller 'incompatible-time-types time-in))
506 (set-time-type! time-out time-utc)
507 (set-time-nanosecond! time-out (time-nanosecond time-in))
508 (set-time-second! time-out (- (time-second time-in)
509 (priv:leap-second-delta
510 (time-second time-in))))
513 (define (time-tai->time-utc time-in)
514 (priv:time-tai->time-utc! time-in (make-time-unnormalized #f #f #f) 'time-tai->time-utc))
517 (define (time-tai->time-utc! time-in)
518 (priv:time-tai->time-utc! time-in time-in 'time-tai->time-utc!))
520 (define (priv:time-utc->time-tai! time-in time-out caller)
521 (if (not (eq? (time-type time-in) time-utc))
522 (priv:time-error caller 'incompatible-time-types time-in))
523 (set-time-type! time-out time-tai)
524 (set-time-nanosecond! time-out (time-nanosecond time-in))
525 (set-time-second! time-out (+ (time-second time-in)
526 (priv:leap-second-delta
527 (time-second time-in))))
530 (define (time-utc->time-tai time-in)
531 (priv:time-utc->time-tai! time-in (make-time-unnormalized #f #f #f) 'time-utc->time-tai))
533 (define (time-utc->time-tai! time-in)
534 (priv:time-utc->time-tai! time-in time-in 'time-utc->time-tai!))
536 ;; -- these depend on time-monotonic having the same definition as time-tai!
537 (define (time-monotonic->time-utc time-in)
538 (if (not (eq? (time-type time-in) time-monotonic))
539 (priv:time-error caller 'incompatible-time-types time-in))
540 (let ((ntime (copy-time time-in)))
541 (set-time-type! ntime time-tai)
542 (priv:time-tai->time-utc! ntime ntime 'time-monotonic->time-utc)))
544 (define (time-monotonic->time-utc! time-in)
545 (if (not (eq? (time-type time-in) time-monotonic))
546 (priv:time-error caller 'incompatible-time-types time-in))
547 (set-time-type! time-in time-tai)
548 (priv:time-tai->time-utc! ntime ntime 'time-monotonic->time-utc))
550 (define (time-monotonic->time-tai time-in)
551 (if (not (eq? (time-type time-in) time-monotonic))
552 (priv:time-error caller 'incompatible-time-types time-in))
553 (let ((ntime (copy-time time-in)))
554 (set-time-type! ntime time-tai)
557 (define (time-monotonic->time-tai! time-in)
558 (if (not (eq? (time-type time-in) time-monotonic))
559 (priv:time-error caller 'incompatible-time-types time-in))
560 (set-time-type! time-in time-tai)
563 (define (time-utc->time-monotonic time-in)
564 (if (not (eq? (time-type time-in) time-utc))
565 (priv:time-error caller 'incompatible-time-types time-in))
566 (let ((ntime (priv:time-utc->time-tai! time-in (make-time-unnormalized #f #f #f)
567 'time-utc->time-monotonic)))
568 (set-time-type! ntime time-monotonic)
571 (define (time-utc->time-monotonic! time-in)
572 (if (not (eq? (time-type time-in) time-utc))
573 (priv:time-error caller 'incompatible-time-types time-in))
574 (let ((ntime (priv:time-utc->time-tai! time-in time-in
575 'time-utc->time-monotonic!)))
576 (set-time-type! ntime time-monotonic)
579 (define (time-tai->time-monotonic time-in)
580 (if (not (eq? (time-type time-in) time-tai))
581 (priv:time-error caller 'incompatible-time-types time-in))
582 (let ((ntime (copy-time time-in)))
583 (set-time-type! ntime time-monotonic)
586 (define (time-tai->time-monotonic! time-in)
587 (if (not (eq? (time-type time-in) time-tai))
588 (priv:time-error caller 'incompatible-time-types time-in))
589 (set-time-type! time-in time-monotonic)
592 ;; -- Date Structures
594 ;; FIXME: to be really safe, perhaps we should normalize the
595 ;; seconds/nanoseconds/minutes coming in to make-date...
597 (define-record-type date
598 (make-date nanosecond second minute
603 (nanosecond date-nanosecond set-date-nanosecond!)
604 (second date-second set-date-second!)
605 (minute date-minute set-date-minute!)
606 (hour date-hour set-date-hour!)
607 (day date-day set-date-day!)
608 (month date-month set-date-month!)
609 (year date-year set-date-year!)
610 (zone-offset date-zone-offset set-date-zone-offset!))
612 ;; gives the julian day which starts at noon.
613 (define (priv:encode-julian-day-number day month year)
614 (let* ((a (quotient (- 14 month) 12))
615 (y (- (+ year 4800) a (if (negative? year) -1 0)))
616 (m (- (+ month (* 12 a)) 3)))
618 (quotient (+ (* 153 m) 2) 5)
625 ;; gives the seconds/date/month/year
626 (define (priv:decode-julian-day-number jdn)
627 (let* ((days (inexact->exact (truncate jdn)))
629 (b (quotient (+ (* 4 a) 3) 146097))
630 (c (- a (quotient (* 146097 b) 4)))
631 (d (quotient (+ (* 4 c) 3) 1461))
632 (e (- c (quotient (* 1461 d) 4)))
633 (m (quotient (+ (* 5 e) 2) 153))
634 (y (+ (* 100 b) d -4800 (quotient m 10))))
635 (values ; seconds date month year
636 (* (- jdn days) priv:sid)
637 (+ e (- (quotient (+ (* 153 m) 2) 5)) 1)
638 (+ m 3 (* -12 (quotient m 10)))
639 (if (>= 0 y) (- y 1) y))))
641 ;; relies on the fact that we named our time zone accessor
642 ;; differently from MzScheme's....
643 ;; This should be written to be OS specific.
645 (define (priv:local-tz-offset utc-time)
646 ;; SRFI uses seconds West, but guile (and libc) use seconds East.
647 (- (tm:gmtoff (localtime (time-second utc-time)))))
649 ;; special thing -- ignores nanos
650 (define (priv:time->julian-day-number seconds tz-offset)
651 (+ (/ (+ seconds tz-offset priv:sihd)
653 priv:tai-epoch-in-jd))
655 (define (priv:leap-second? second)
656 (and (assoc second priv:leap-second-table) #t))
658 (define (time-utc->date time . tz-offset)
659 (if (not (eq? (time-type time) time-utc))
660 (priv:time-error 'time->date 'incompatible-time-types time))
661 (let* ((offset (if (null? tz-offset)
662 (priv:local-tz-offset time)
664 (leap-second? (priv:leap-second? (+ offset (time-second time))))
665 (jdn (priv:time->julian-day-number (if leap-second?
666 (- (time-second time) 1)
670 (call-with-values (lambda () (priv:decode-julian-day-number jdn))
671 (lambda (secs date month year)
672 ;; secs is a real because jdn is a real in Guile;
673 ;; but it is conceptionally an integer.
674 (let* ((int-secs (inexact->exact (round secs)))
675 (hours (quotient int-secs (* 60 60)))
676 (rem (remainder int-secs (* 60 60)))
677 (minutes (quotient rem 60))
678 (seconds (remainder rem 60)))
679 (make-date (time-nanosecond time)
680 (if leap-second? (+ seconds 1) seconds)
688 (define (time-tai->date time . tz-offset)
689 (if (not (eq? (time-type time) time-tai))
690 (priv:time-error 'time->date 'incompatible-time-types time))
691 (let* ((offset (if (null? tz-offset)
692 (priv:local-tz-offset (time-tai->time-utc time))
694 (seconds (- (time-second time)
695 (priv:leap-second-delta (time-second time))))
696 (leap-second? (priv:leap-second? (+ offset seconds)))
697 (jdn (priv:time->julian-day-number (if leap-second?
701 (call-with-values (lambda () (priv:decode-julian-day-number jdn))
702 (lambda (secs date month year)
703 ;; secs is a real because jdn is a real in Guile;
704 ;; but it is conceptionally an integer.
705 ;; adjust for leap seconds if necessary ...
706 (let* ((int-secs (inexact->exact (round secs)))
707 (hours (quotient int-secs (* 60 60)))
708 (rem (remainder int-secs (* 60 60)))
709 (minutes (quotient rem 60))
710 (seconds (remainder rem 60)))
711 (make-date (time-nanosecond time)
712 (if leap-second? (+ seconds 1) seconds)
720 ;; this is the same as time-tai->date.
721 (define (time-monotonic->date time . tz-offset)
722 (if (not (eq? (time-type time) time-monotonic))
723 (priv:time-error 'time->date 'incompatible-time-types time))
724 (let* ((offset (if (null? tz-offset)
725 (priv:local-tz-offset (time-monotonic->time-utc time))
727 (seconds (- (time-second time)
728 (priv:leap-second-delta (time-second time))))
729 (leap-second? (priv:leap-second? (+ offset seconds)))
730 (jdn (priv:time->julian-day-number (if leap-second?
734 (call-with-values (lambda () (priv:decode-julian-day-number jdn))
735 (lambda (secs date month year)
736 ;; secs is a real because jdn is a real in Guile;
737 ;; but it is conceptionally an integer.
738 ;; adjust for leap seconds if necessary ...
739 (let* ((int-secs (inexact->exact (round secs)))
740 (hours (quotient int-secs (* 60 60)))
741 (rem (remainder int-secs (* 60 60)))
742 (minutes (quotient rem 60))
743 (seconds (remainder rem 60)))
744 (make-date (time-nanosecond time)
745 (if leap-second? (+ seconds 1) seconds)
753 (define (date->time-utc date)
754 (let* ((jdays (- (priv:encode-julian-day-number (date-day date)
757 priv:tai-epoch-in-jd))
758 ;; jdays is an integer plus 1/2,
759 (jdays-1/2 (inexact->exact (- jdays 1/2))))
762 (date-nanosecond date)
763 (+ (* jdays-1/2 24 60 60)
764 (* (date-hour date) 60 60)
765 (* (date-minute date) 60)
767 (- (date-zone-offset date))))))
769 (define (date->time-tai date)
770 (time-utc->time-tai! (date->time-utc date)))
772 (define (date->time-monotonic date)
773 (time-utc->time-monotonic! (date->time-utc date)))
775 (define (priv:leap-year? year)
776 (or (= (modulo year 400) 0)
777 (and (= (modulo year 4) 0) (not (= (modulo year 100) 0)))))
779 (define (leap-year? date)
780 (priv:leap-year? (date-year date)))
782 ;; Map 1-based month number M to number of days in the year before the
783 ;; start of month M (in a non-leap year).
784 (define priv:month-assoc '((1 . 0) (2 . 31) (3 . 59) (4 . 90)
785 (5 . 120) (6 . 151) (7 . 181) (8 . 212)
786 (9 . 243) (10 . 273) (11 . 304) (12 . 334)))
788 (define (priv:year-day day month year)
789 (let ((days-pr (assoc month priv:month-assoc)))
791 (priv:error 'date-year-day 'invalid-month-specification month))
792 (if (and (priv:leap-year? year) (> month 2))
793 (+ day (cdr days-pr) 1)
794 (+ day (cdr days-pr)))))
796 (define (date-year-day date)
797 (priv:year-day (date-day date) (date-month date) (date-year date)))
800 (define (priv:week-day day month year)
801 (let* ((a (quotient (- 14 month) 12))
803 (m (+ month (* 12 a) -2)))
809 (quotient (* 31 m) 12))
812 (define (date-week-day date)
813 (priv:week-day (date-day date) (date-month date) (date-year date)))
815 (define (priv:days-before-first-week date day-of-week-starting-week)
816 (let* ((first-day (make-date 0 0 0 0
821 (fdweek-day (date-week-day first-day)))
822 (modulo (- day-of-week-starting-week fdweek-day)
825 ;; The "-1" here is a fix for the reference implementation, to make a new
826 ;; week start on the given day-of-week-starting-week. date-year-day returns
827 ;; a day starting from 1 for 1st Jan.
829 (define (date-week-number date day-of-week-starting-week)
830 (quotient (- (date-year-day date)
832 (priv:days-before-first-week date day-of-week-starting-week))
835 (define (current-date . tz-offset)
836 (let ((time (current-time time-utc)))
839 (if (null? tz-offset)
840 (priv:local-tz-offset time)
843 ;; given a 'two digit' number, find the year within 50 years +/-
844 (define (priv:natural-year n)
845 (let* ((current-year (date-year (current-date)))
846 (current-century (* (quotient current-year 100) 100)))
850 ((<= (- (+ current-century n) current-year) 50) (+ current-century n))
851 (else (+ (- current-century 100) n)))))
853 (define (date->julian-day date)
854 (let ((nanosecond (date-nanosecond date))
855 (second (date-second date))
856 (minute (date-minute date))
857 (hour (date-hour date))
858 (day (date-day date))
859 (month (date-month date))
860 (year (date-year date)))
861 (+ (priv:encode-julian-day-number day month year)
863 (+ (/ (+ (* hour 60 60)
866 (/ nanosecond priv:nano))
869 (define (date->modified-julian-day date)
870 (- (date->julian-day date)
873 (define (time-utc->julian-day time)
874 (if (not (eq? (time-type time) time-utc))
875 (priv:time-error 'time->date 'incompatible-time-types time))
876 (+ (/ (+ (time-second time) (/ (time-nanosecond time) priv:nano))
878 priv:tai-epoch-in-jd))
880 (define (time-utc->modified-julian-day time)
881 (- (time-utc->julian-day time)
884 (define (time-tai->julian-day time)
885 (if (not (eq? (time-type time) time-tai))
886 (priv:time-error 'time->date 'incompatible-time-types time))
887 (+ (/ (+ (- (time-second time)
888 (priv:leap-second-delta (time-second time)))
889 (/ (time-nanosecond time) priv:nano))
891 priv:tai-epoch-in-jd))
893 (define (time-tai->modified-julian-day time)
894 (- (time-tai->julian-day time)
897 ;; this is the same as time-tai->julian-day
898 (define (time-monotonic->julian-day time)
899 (if (not (eq? (time-type time) time-monotonic))
900 (priv:time-error 'time->date 'incompatible-time-types time))
901 (+ (/ (+ (- (time-second time)
902 (priv:leap-second-delta (time-second time)))
903 (/ (time-nanosecond time) priv:nano))
905 priv:tai-epoch-in-jd))
907 (define (time-monotonic->modified-julian-day time)
908 (- (time-monotonic->julian-day time)
911 (define (julian-day->time-utc jdn)
912 (let ((secs (* priv:sid (- jdn priv:tai-epoch-in-jd))))
913 (receive (seconds parts)
914 (priv:split-real secs)
919 (define (julian-day->time-tai jdn)
920 (time-utc->time-tai! (julian-day->time-utc jdn)))
922 (define (julian-day->time-monotonic jdn)
923 (time-utc->time-monotonic! (julian-day->time-utc jdn)))
925 (define (julian-day->date jdn . tz-offset)
926 (let* ((time (julian-day->time-utc jdn))
927 (offset (if (null? tz-offset)
928 (priv:local-tz-offset time)
930 (time-utc->date time offset)))
932 (define (modified-julian-day->date jdn . tz-offset)
933 (apply julian-day->date (+ jdn 4800001/2)
936 (define (modified-julian-day->time-utc jdn)
937 (julian-day->time-utc (+ jdn 4800001/2)))
939 (define (modified-julian-day->time-tai jdn)
940 (julian-day->time-tai (+ jdn 4800001/2)))
942 (define (modified-julian-day->time-monotonic jdn)
943 (julian-day->time-monotonic (+ jdn 4800001/2)))
945 (define (current-julian-day)
946 (time-utc->julian-day (current-time time-utc)))
948 (define (current-modified-julian-day)
949 (time-utc->modified-julian-day (current-time time-utc)))
951 ;; returns a string rep. of number N, of minimum LENGTH, padded with
952 ;; character PAD-WITH. If PAD-WITH is #f, no padding is done, and it's
953 ;; as if number->string was used. if string is longer than or equal
954 ;; in length to LENGTH, it's as if number->string was used.
956 (define (priv:padding n pad-with length)
957 (let* ((str (number->string n))
958 (str-len (string-length str)))
959 (if (or (>= str-len length)
962 (string-append (make-string (- length str-len) pad-with) str))))
964 (define (priv:last-n-digits i n)
965 (abs (remainder i (expt 10 n))))
967 (define (priv:locale-abbr-weekday n)
968 (vector-ref priv:locale-abbr-weekday-vector n))
970 (define (priv:locale-long-weekday n)
971 (vector-ref priv:locale-long-weekday-vector n))
973 (define (priv:locale-abbr-month n)
974 (vector-ref priv:locale-abbr-month-vector n))
976 (define (priv:locale-long-month n)
977 (vector-ref priv:locale-long-month-vector n))
979 (define (priv:vector-find needle haystack comparator)
980 (let ((len (vector-length haystack)))
981 (define (priv:vector-find-int index)
984 ((comparator needle (vector-ref haystack index)) index)
985 (else (priv:vector-find-int (+ index 1)))))
986 (priv:vector-find-int 0)))
988 (define (priv:locale-abbr-weekday->index string)
989 (priv:vector-find string priv:locale-abbr-weekday-vector string=?))
991 (define (priv:locale-long-weekday->index string)
992 (priv:vector-find string priv:locale-long-weekday-vector string=?))
994 (define (priv:locale-abbr-month->index string)
995 (priv:vector-find string priv:locale-abbr-month-vector string=?))
997 (define (priv:locale-long-month->index string)
998 (priv:vector-find string priv:locale-long-month-vector string=?))
1001 ;; FIXME: mkoeppe: Put a symbolic time zone in the date structs.
1002 ;; Print it here instead of the numerical offset if available.
1003 (define (priv:locale-print-time-zone date port)
1004 (priv:tz-printer (date-zone-offset date) port))
1006 ;; FIXME: we should use strftime to determine this dynamically if possible.
1007 ;; Again, locale specific.
1008 (define (priv:locale-am/pm hr)
1009 (if (> hr 11) priv:locale-pm priv:locale-am))
1011 (define (priv:tz-printer offset port)
1013 ((= offset 0) (display "Z" port))
1014 ((negative? offset) (display "-" port))
1015 (else (display "+" port)))
1016 (if (not (= offset 0))
1017 (let ((hours (abs (quotient offset (* 60 60))))
1018 (minutes (abs (quotient (remainder offset (* 60 60)) 60))))
1019 (display (priv:padding hours #\0 2) port)
1020 (display (priv:padding minutes #\0 2) port))))
1022 ;; A table of output formatting directives.
1023 ;; the first time is the format char.
1024 ;; the second is a procedure that takes the date, a padding character
1025 ;; (which might be #f), and the output port.
1027 (define priv:directives
1029 (cons #\~ (lambda (date pad-with port)
1030 (display #\~ port)))
1031 (cons #\a (lambda (date pad-with port)
1032 (display (priv:locale-abbr-weekday (date-week-day date))
1034 (cons #\A (lambda (date pad-with port)
1035 (display (priv:locale-long-weekday (date-week-day date))
1037 (cons #\b (lambda (date pad-with port)
1038 (display (priv:locale-abbr-month (date-month date))
1040 (cons #\B (lambda (date pad-with port)
1041 (display (priv:locale-long-month (date-month date))
1043 (cons #\c (lambda (date pad-with port)
1044 (display (date->string date priv:locale-date-time-format) port)))
1045 (cons #\d (lambda (date pad-with port)
1046 (display (priv:padding (date-day date)
1049 (cons #\D (lambda (date pad-with port)
1050 (display (date->string date "~m/~d/~y") port)))
1051 (cons #\e (lambda (date pad-with port)
1052 (display (priv:padding (date-day date)
1055 (cons #\f (lambda (date pad-with port)
1056 (if (> (date-nanosecond date)
1058 (display (priv:padding (+ (date-second date) 1)
1061 (display (priv:padding (date-second date)
1066 (date-nanosecond date)
1068 (let* ((ns (number->string f))
1069 (le (string-length ns)))
1072 (display priv:locale-number-separator port)
1073 (display (substring ns 2 le) port)))))))
1074 (cons #\h (lambda (date pad-with port)
1075 (display (date->string date "~b") port)))
1076 (cons #\H (lambda (date pad-with port)
1077 (display (priv:padding (date-hour date)
1080 (cons #\I (lambda (date pad-with port)
1081 (let ((hr (date-hour date)))
1083 (display (priv:padding (- hr 12)
1086 (display (priv:padding hr
1089 (cons #\j (lambda (date pad-with port)
1090 (display (priv:padding (date-year-day date)
1093 (cons #\k (lambda (date pad-with port)
1094 (display (priv:padding (date-hour date)
1097 (cons #\l (lambda (date pad-with port)
1098 (let ((hr (if (> (date-hour date) 12)
1099 (- (date-hour date) 12) (date-hour date))))
1100 (display (priv:padding hr #\Space 2)
1102 (cons #\m (lambda (date pad-with port)
1103 (display (priv:padding (date-month date)
1106 (cons #\M (lambda (date pad-with port)
1107 (display (priv:padding (date-minute date)
1110 (cons #\n (lambda (date pad-with port)
1112 (cons #\N (lambda (date pad-with port)
1113 (display (priv:padding (date-nanosecond date)
1116 (cons #\p (lambda (date pad-with port)
1117 (display (priv:locale-am/pm (date-hour date)) port)))
1118 (cons #\r (lambda (date pad-with port)
1119 (display (date->string date "~I:~M:~S ~p") port)))
1120 (cons #\s (lambda (date pad-with port)
1121 (display (time-second (date->time-utc date)) port)))
1122 (cons #\S (lambda (date pad-with port)
1123 (if (> (date-nanosecond date)
1125 (display (priv:padding (+ (date-second date) 1)
1128 (display (priv:padding (date-second date)
1131 (cons #\t (lambda (date pad-with port)
1132 (display #\Tab port)))
1133 (cons #\T (lambda (date pad-with port)
1134 (display (date->string date "~H:~M:~S") port)))
1135 (cons #\U (lambda (date pad-with port)
1136 (if (> (priv:days-before-first-week date 0) 0)
1137 (display (priv:padding (+ (date-week-number date 0) 1)
1139 (display (priv:padding (date-week-number date 0)
1141 (cons #\V (lambda (date pad-with port)
1142 (display (priv:padding (date-week-number date 1)
1144 (cons #\w (lambda (date pad-with port)
1145 (display (date-week-day date) port)))
1146 (cons #\x (lambda (date pad-with port)
1147 (display (date->string date priv:locale-short-date-format) port)))
1148 (cons #\X (lambda (date pad-with port)
1149 (display (date->string date priv:locale-time-format) port)))
1150 (cons #\W (lambda (date pad-with port)
1151 (if (> (priv:days-before-first-week date 1) 0)
1152 (display (priv:padding (+ (date-week-number date 1) 1)
1154 (display (priv:padding (date-week-number date 1)
1156 (cons #\y (lambda (date pad-with port)
1157 (display (priv:padding (priv:last-n-digits
1162 (cons #\Y (lambda (date pad-with port)
1163 (display (date-year date) port)))
1164 (cons #\z (lambda (date pad-with port)
1165 (priv:tz-printer (date-zone-offset date) port)))
1166 (cons #\Z (lambda (date pad-with port)
1167 (priv:locale-print-time-zone date port)))
1168 (cons #\1 (lambda (date pad-with port)
1169 (display (date->string date "~Y-~m-~d") port)))
1170 (cons #\2 (lambda (date pad-with port)
1171 (display (date->string date "~k:~M:~S~z") port)))
1172 (cons #\3 (lambda (date pad-with port)
1173 (display (date->string date "~k:~M:~S") port)))
1174 (cons #\4 (lambda (date pad-with port)
1175 (display (date->string date "~Y-~m-~dT~k:~M:~S~z") port)))
1176 (cons #\5 (lambda (date pad-with port)
1177 (display (date->string date "~Y-~m-~dT~k:~M:~S") port)))))
1180 (define (priv:get-formatter char)
1181 (let ((associated (assoc char priv:directives)))
1182 (if associated (cdr associated) #f)))
1184 (define (priv:date-printer date index format-string str-len port)
1185 (if (>= index str-len)
1187 (let ((current-char (string-ref format-string index)))
1188 (if (not (char=? current-char #\~))
1190 (display current-char port)
1191 (priv:date-printer date (+ index 1) format-string str-len port))
1192 (if (= (+ index 1) str-len) ; bad format string.
1193 (priv:time-error 'priv:date-printer 'bad-date-format-string
1195 (let ((pad-char? (string-ref format-string (+ index 1))))
1197 ((char=? pad-char? #\-)
1198 (if (= (+ index 2) str-len) ; bad format string.
1199 (priv:time-error 'priv:date-printer
1200 'bad-date-format-string
1202 (let ((formatter (priv:get-formatter
1203 (string-ref format-string
1206 (priv:time-error 'priv:date-printer
1207 'bad-date-format-string
1210 (formatter date #f port)
1211 (priv:date-printer date
1217 ((char=? pad-char? #\_)
1218 (if (= (+ index 2) str-len) ; bad format string.
1219 (priv:time-error 'priv:date-printer
1220 'bad-date-format-string
1222 (let ((formatter (priv:get-formatter
1223 (string-ref format-string
1226 (priv:time-error 'priv:date-printer
1227 'bad-date-format-string
1230 (formatter date #\Space port)
1231 (priv:date-printer date
1237 (let ((formatter (priv:get-formatter
1238 (string-ref format-string
1241 (priv:time-error 'priv:date-printer
1242 'bad-date-format-string
1245 (formatter date #\0 port)
1246 (priv:date-printer date
1253 (define (date->string date . format-string)
1254 (let ((str-port (open-output-string))
1255 (fmt-str (if (null? format-string) "~c" (car format-string))))
1256 (priv:date-printer date 0 fmt-str (string-length fmt-str) str-port)
1257 (get-output-string str-port)))
1259 (define (priv:char->int ch)
1271 (else (priv:time-error 'bad-date-template-string
1272 (list "Non-integer character" ch i)))))
1274 ;; read an integer upto n characters long on port; upto -> #f is any length
1275 (define (priv:integer-reader upto port)
1276 (let loop ((accum 0) (nchars 0))
1277 (let ((ch (peek-char port)))
1278 (if (or (eof-object? ch)
1279 (not (char-numeric? ch))
1280 (and upto (>= nchars upto)))
1282 (loop (+ (* accum 10) (priv:char->int (read-char port)))
1285 (define (priv:make-integer-reader upto)
1287 (priv:integer-reader upto port)))
1289 ;; read *exactly* n characters and convert to integer; could be padded
1290 (define (priv:integer-reader-exact n port)
1291 (let ((padding-ok #t))
1292 (define (accum-int port accum nchars)
1293 (let ((ch (peek-char port)))
1295 ((>= nchars n) accum)
1297 (priv:time-error 'string->date 'bad-date-template-string
1298 "Premature ending to integer read."))
1300 (set! padding-ok #f)
1302 (+ (* accum 10) (priv:char->int (read-char port)))
1305 (read-char port) ; consume padding
1306 (accum-int port accum (+ nchars 1)))
1307 (else ; padding where it shouldn't be
1308 (priv:time-error 'string->date 'bad-date-template-string
1309 "Non-numeric characters in integer read.")))))
1310 (accum-int port 0 0)))
1313 (define (priv:make-integer-exact-reader n)
1315 (priv:integer-reader-exact n port)))
1317 (define (priv:zone-reader port)
1320 (let ((ch (read-char port)))
1321 (if (eof-object? ch)
1322 (priv:time-error 'string->date 'bad-date-template-string
1323 (list "Invalid time zone +/-" ch)))
1324 (if (or (char=? ch #\Z) (char=? ch #\z))
1328 ((char=? ch #\+) (set! positive? #t))
1329 ((char=? ch #\-) (set! positive? #f))
1331 (priv:time-error 'string->date 'bad-date-template-string
1332 (list "Invalid time zone +/-" ch))))
1333 (let ((ch (read-char port)))
1334 (if (eof-object? ch)
1335 (priv:time-error 'string->date 'bad-date-template-string
1336 (list "Invalid time zone number" ch)))
1337 (set! offset (* (priv:char->int ch)
1339 (let ((ch (read-char port)))
1340 (if (eof-object? ch)
1341 (priv:time-error 'string->date 'bad-date-template-string
1342 (list "Invalid time zone number" ch)))
1343 (set! offset (+ offset (* (priv:char->int ch)
1345 (let ((ch (read-char port)))
1346 (if (eof-object? ch)
1347 (priv:time-error 'string->date 'bad-date-template-string
1348 (list "Invalid time zone number" ch)))
1349 (set! offset (+ offset (* (priv:char->int ch)
1351 (let ((ch (read-char port)))
1352 (if (eof-object? ch)
1353 (priv:time-error 'string->date 'bad-date-template-string
1354 (list "Invalid time zone number" ch)))
1355 (set! offset (+ offset (* (priv:char->int ch)
1357 (if positive? offset (- offset)))))))
1359 ;; looking at a char, read the char string, run thru indexer, return index
1360 (define (priv:locale-reader port indexer)
1362 (define (read-char-string result)
1363 (let ((ch (peek-char port)))
1364 (if (char-alphabetic? ch)
1365 (read-char-string (cons (read-char port) result))
1366 (list->string (reverse! result)))))
1368 (let* ((str (read-char-string '()))
1369 (index (indexer str)))
1370 (if index index (priv:time-error 'string->date
1371 'bad-date-template-string
1372 (list "Invalid string for " indexer)))))
1374 (define (priv:make-locale-reader indexer)
1376 (priv:locale-reader port indexer)))
1378 (define (priv:make-char-id-reader char)
1380 (if (char=? char (read-char port))
1382 (priv:time-error 'string->date
1383 'bad-date-template-string
1384 "Invalid character match."))))
1386 ;; A List of formatted read directives.
1387 ;; Each entry is a list.
1388 ;; 1. the character directive;
1389 ;; a procedure, which takes a character as input & returns
1390 ;; 2. #t as soon as a character on the input port is acceptable
1392 ;; 3. a port reader procedure that knows how to read the current port
1393 ;; for a value. Its one parameter is the port.
1394 ;; 4. a action procedure, that takes the value (from 3.) and some
1395 ;; object (here, always the date) and (probably) side-effects it.
1396 ;; In some cases (e.g., ~A) the action is to do nothing
1398 (define priv:read-directives
1399 (let ((ireader4 (priv:make-integer-reader 4))
1400 (ireader2 (priv:make-integer-reader 2))
1401 (ireaderf (priv:make-integer-reader #f))
1402 (eireader2 (priv:make-integer-exact-reader 2))
1403 (eireader4 (priv:make-integer-exact-reader 4))
1404 (locale-reader-abbr-weekday (priv:make-locale-reader
1405 priv:locale-abbr-weekday->index))
1406 (locale-reader-long-weekday (priv:make-locale-reader
1407 priv:locale-long-weekday->index))
1408 (locale-reader-abbr-month (priv:make-locale-reader
1409 priv:locale-abbr-month->index))
1410 (locale-reader-long-month (priv:make-locale-reader
1411 priv:locale-long-month->index))
1412 (char-fail (lambda (ch) #t))
1413 (do-nothing (lambda (val object) (values))))
1416 (list #\~ char-fail (priv:make-char-id-reader #\~) do-nothing)
1417 (list #\a char-alphabetic? locale-reader-abbr-weekday do-nothing)
1418 (list #\A char-alphabetic? locale-reader-long-weekday do-nothing)
1419 (list #\b char-alphabetic? locale-reader-abbr-month
1420 (lambda (val object)
1421 (set-date-month! object val)))
1422 (list #\B char-alphabetic? locale-reader-long-month
1423 (lambda (val object)
1424 (set-date-month! object val)))
1425 (list #\d char-numeric? ireader2 (lambda (val object)
1428 (list #\e char-fail eireader2 (lambda (val object)
1429 (set-date-day! object val)))
1430 (list #\h char-alphabetic? locale-reader-abbr-month
1431 (lambda (val object)
1432 (set-date-month! object val)))
1433 (list #\H char-numeric? ireader2 (lambda (val object)
1434 (set-date-hour! object val)))
1435 (list #\k char-fail eireader2 (lambda (val object)
1436 (set-date-hour! object val)))
1437 (list #\m char-numeric? ireader2 (lambda (val object)
1438 (set-date-month! object val)))
1439 (list #\M char-numeric? ireader2 (lambda (val object)
1442 (list #\S char-numeric? ireader2 (lambda (val object)
1443 (set-date-second! object val)))
1444 (list #\y char-fail eireader2
1445 (lambda (val object)
1446 (set-date-year! object (priv:natural-year val))))
1447 (list #\Y char-numeric? ireader4 (lambda (val object)
1448 (set-date-year! object val)))
1449 (list #\z (lambda (c)
1454 priv:zone-reader (lambda (val object)
1455 (set-date-zone-offset! object val))))))
1457 (define (priv:string->date date index format-string str-len port template-string)
1458 (define (skip-until port skipper)
1459 (let ((ch (peek-char port)))
1460 (if (eof-object? port)
1461 (priv:time-error 'string->date 'bad-date-format-string template-string)
1462 (if (not (skipper ch))
1463 (begin (read-char port) (skip-until port skipper))))))
1464 (if (>= index str-len)
1467 (let ((current-char (string-ref format-string index)))
1468 (if (not (char=? current-char #\~))
1469 (let ((port-char (read-char port)))
1470 (if (or (eof-object? port-char)
1471 (not (char=? current-char port-char)))
1472 (priv:time-error 'string->date
1473 'bad-date-format-string template-string))
1474 (priv:string->date date
1480 ;; otherwise, it's an escape, we hope
1481 (if (> (+ index 1) str-len)
1482 (priv:time-error 'string->date
1483 'bad-date-format-string template-string)
1484 (let* ((format-char (string-ref format-string (+ index 1)))
1485 (format-info (assoc format-char priv:read-directives)))
1486 (if (not format-info)
1487 (priv:time-error 'string->date
1488 'bad-date-format-string template-string)
1490 (let ((skipper (cadr format-info))
1491 (reader (caddr format-info))
1492 (actor (cadddr format-info)))
1493 (skip-until port skipper)
1494 (let ((val (reader port)))
1495 (if (eof-object? val)
1496 (priv:time-error 'string->date
1497 'bad-date-format-string
1500 (priv:string->date date
1505 template-string))))))))))
1507 (define (string->date input-string template-string)
1508 (define (priv:date-ok? date)
1509 (and (date-nanosecond date)
1516 (date-zone-offset date)))
1517 (let ((newdate (make-date 0 0 0 0 #f #f #f #f)))
1518 (priv:string->date newdate
1521 (string-length template-string)
1522 (open-input-string input-string)
1524 (if (not (date-zone-offset newdate))
1526 ;; this is necessary to get DST right -- as far as we can
1527 ;; get it right (think of the double/missing hour in the
1528 ;; night when we are switching between normal time and DST).
1529 (set-date-zone-offset! newdate
1530 (priv:local-tz-offset
1531 (make-time time-utc 0 0)))
1532 (set-date-zone-offset! newdate
1533 (priv:local-tz-offset
1534 (date->time-utc newdate)))))
1535 (if (priv:date-ok? newdate)
1539 'bad-date-format-string
1540 (list "Incomplete date read. " newdate template-string)))))
1542 ;;; srfi-19.scm ends here