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1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 | ;; SRFI-19: Time Data Types and Procedures.
;;
;; Debian maintainer's note: Originally published under the license hereunder,
;; this file has since been elevated to the public domain by its author,
;; Will Fitzgerald.
;;
;;
;; Copyright (C) I/NET, Inc. (2000, 2002, 2003). All Rights Reserved.
;;
;; This document and translations of it may be copied and furnished to others,
;; and derivative works that comment on or otherwise explain it or assist in its
;; implementation may be prepared, copied, published and distributed, in whole or
;; in part, without restriction of any kind, provided that the above copyright
;; notice and this paragraph are included on all such copies and derivative works.
;; However, this document itself may not be modified in any way, such as by
;; removing the copyright notice or references to the Scheme Request For
;; Implementation process or editors, except as needed for the purpose of
;; developing SRFIs in which case the procedures for copyrights defined in the SRFI
;; process must be followed, or as required to translate it into languages other
;; than English.
;;
;; The limited permissions granted above are perpetual and will not be revoked
;; by the authors or their successors or assigns.
;;
;; This document and the information contained herein is provided on an "AS IS"
;; basis and THE AUTHOR AND THE SRFI EDITORS DISCLAIM ALL WARRANTIES, EXPRESS OR
;; IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
;; INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
;; MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
;; -- Bug fixes.
;;
;; MAKE-TIME had parameters seconds and nanoseconds reversed; change all
;; references in file to match. Will F: 2002-10-15
;;
;; DATE-YEAR-DAY returned the wrong day; tm:year-day fixed to do the right
;; thing. Will F: 2002-10-15
;; It also called an undefined error procedure.
;;
;; DISPLAYING procedure removed. Will F: 2002-10-15.
;;
;; TM:NANO constant corrected. 2002-11-04.
;;
;; The following fixes by Will Fitzgerald, February, 2003.
;; -- Thanks to Steven Ma and others.
;;
;; (CURRENT-TIME 'TIME-THREAD) added.
;;
;; TIME-RESOLUTION for TIME-PROCESS added.
;;
;; TIME comparison procedures (time=?, etc. fixed.
;;
;; Corrected errors in converting between TAI and UTC time.
;;
;; TAI and UTC date converters no longer look at leap seconds,
;; which was an error.
;;
;; corrections to calls to tm:time-error
;;
;; timezone offset not used in date->time-utc and date->julian-day
;;
;; typos in tm:integer-reader-exact, tm:string->date,
;; time-monotonic->time-utc!, tm:char->int fixed
;;
;; corrected "~k", "~f" formatting for date->string (includes fix for
;; "~4"
;;
;; 'split-real' fixed.
;;
;; fixed julian-day->time-utc and variants.
;; --------------------------------------------------------------
;;; SCSH portability: import receive from srfi-8
;;; -- we want receive later on for a couple of small things
;;
;; :OPTIONAL is nice, too
(define-syntax :optional
(syntax-rules ()
((_ val default-value)
(if (null? val) default-value (car val)))))
(define time-tai 'time-tai)
(define time-utc 'time-utc)
(define time-monotonic 'time-monotonic)
(define time-thread 'time-thread)
(define time-process 'time-process)
(define time-duration 'time-duration)
;; example of extension (MZScheme specific)
(define time-gc 'time-gc)
;;-- LOCALE dependent constants
(define tm:locale-number-separator ".")
(define tm:locale-abbr-weekday-vector (vector "Sun" "Mon" "Tue" "Wed"
"Thu" "Fri" "Sat"))
(define tm:locale-long-weekday-vector (vector "Sunday" "Monday"
"Tuesday" "Wednesday"
"Thursday" "Friday"
"Saturday"))
;; note empty string in 0th place.
(define tm:locale-abbr-month-vector (vector "" "Jan" "Feb" "Mar"
"Apr" "May" "Jun" "Jul"
"Aug" "Sep" "Oct" "Nov"
"Dec"))
(define tm:locale-long-month-vector (vector "" "January" "February"
"March" "April" "May"
"June" "July" "August"
"September" "October"
"November" "December"))
(define tm:locale-pm "PM")
(define tm:locale-am "AM")
;; See date->string
(define tm:locale-date-time-format "~a ~b ~d ~H:~M:~S~z ~Y")
(define tm:locale-short-date-format "~m/~d/~y")
(define tm:locale-time-format "~H:~M:~S")
(define tm:iso-8601-date-time-format "~Y-~m-~dT~H:~M:~S~z")
;;-- Miscellaneous Constants.
;;-- only the tm:tai-epoch-in-jd might need changing if
;; a different epoch is used.
(define tm:nano (expt 10 9))
(define tm:sid 86400) ; seconds in a day
(define tm:sihd 43200) ; seconds in a half day
(define tm:tai-epoch-in-jd 4881175/2) ; julian day number for 'the epoch'
;; SCSH portability
(define tm:ns/quantum (/ tm:nano (ticks/sec)))
;;; A Very simple Error system for the time procedures
;;;
(define tm:time-error-types
'(invalid-clock-type
unsupported-clock-type
incompatible-time-types
not-duration
dates-are-immutable
bad-date-format-string
bad-date-template-string
invalid-month-specification
))
(define (tm:time-error caller type value)
(if (member type tm:time-error-types)
(if value
(error caller "TIME-ERROR type ~S: ~S" type value)
(error caller "TIME-ERROR type ~S" type))
(error caller "TIME-ERROR unsupported error type ~S" type)))
;; A table of leap seconds
;; See ftp://maia.usno.navy.mil/ser7/tai-utc.dat
;; and update as necessary.
;; this procedures reads the file in the abover
;; format and creates the leap second table
;; it also calls the almost standard, but not R5 procedures read-line
;; & open-input-string
;; ie (set! tm:leap-second-table (tm:read-tai-utc-date "tai-utc.dat"))
(define (tm:read-tai-utc-data filename)
(define (convert-jd jd)
(* (- (inexact->exact jd) tm:tai-epoch-in-jd) tm:sid))
(define (convert-sec sec)
(inexact->exact sec))
(let ( (port (open-input-file filename))
(table '()) )
(let loop ((line (read-line port)))
(if (not (eof-object? line))
(begin
(let* ( (data (read (open-input-string (string-append "(" line ")"))))
(year (car data))
(jd (cadddr (cdr data)))
(secs (cadddr (cdddr data))) )
(if (>= year 1972)
(set! table (cons (cons (convert-jd jd) (convert-sec secs)) table)))
(loop (read-line port))))))
table))
;; each entry is ( utc seconds since epoch . # seconds to add for tai )
;; note they go higher to lower, and end in 1972.
(define tm:leap-second-table
'((1136073600 . 33)
(915148800 . 32)
(867715200 . 31)
(820454400 . 30)
(773020800 . 29)
(741484800 . 28)
(709948800 . 27)
(662688000 . 26)
(631152000 . 25)
(567993600 . 24)
(489024000 . 23)
(425865600 . 22)
(394329600 . 21)
(362793600 . 20)
(315532800 . 19)
(283996800 . 18)
(252460800 . 17)
(220924800 . 16)
(189302400 . 15)
(157766400 . 14)
(126230400 . 13)
(94694400 . 12)
(78796800 . 11)
(63072000 . 10)))
(define (read-leap-second-table filename)
(set! tm:leap-second-table (tm:read-tai-utc-data filename))
(values))
(define (tm:leap-second-delta utc-seconds)
(letrec ( (lsd (lambda (table)
(cond
((>= utc-seconds (caar table))
(cdar table))
(else (lsd (cdr table)))))) )
(if (< utc-seconds (* (- 1972 1970) 365 tm:sid)) 0
(lsd tm:leap-second-table))))
;; going from tai seconds to utc seconds ...
(define (tm:leap-second-neg-delta tai-seconds)
(letrec ( (lsd (lambda (table)
(cond ((null? table) 0)
((<= (cdar table) (- tai-seconds (caar table)))
(cdar table))
(else (lsd (cdr table)))))) )
(if (< tai-seconds (* (- 1972 1970) 365 tm:sid)) 0
(lsd tm:leap-second-table))))
;;; the time structure; creates the accessors, too.
;;; wf: changed to match srfi documentation. uses mzscheme structures & inspectors
(define-record-type :time
(make-time type nanosecond second)
time?
(type time-type set-time-type!)
(nanosecond time-nanosecond set-time-nanosecond!)
(second time-second set-time-second!))
(define (copy-time time)
(let ((ntime (make-time #f #f #f)))
(set-time-type! ntime (time-type time))
(set-time-second! ntime (time-second time))
(set-time-nanosecond! ntime (time-nanosecond time))
ntime))
;;; current-time
;;; specific time getters.
;;; these should be rewritten to be os specific.
;;
;; -- using gnu gettimeofday() would be useful here -- gets
;; second + millisecond
;; let's pretend we do, using mzscheme's current-seconds & current-milliseconds
;; this is supposed to return utc.
;;
;; SCSH portability: scsh has even more than milliseconds: ticks
; (define (tm:get-time-of-day)
; (values (current-seconds)
; (abs (remainder (current-milliseconds) 1000))))
;; SCSH portability: use time+ticks
(define (tm:current-time-utc)
(receive (seconds quanta) (time+ticks)
(make-time time-utc
(* quanta tm:ns/quantum)
seconds )))
;; SCSH portability: use time+ticks
(define (tm:current-time-tai)
(receive (seconds quanta) (time+ticks)
(make-time time-tai
(* quanta tm:ns/quantum)
(+ seconds (tm:leap-second-delta seconds)))))
;; SCSH portability: use tm:ns/quantum
(define (tm:current-time-ms-time time-type proc)
(let ((current-ms (proc)))
(make-time time-type
(* (remainder current-ms 1000) tm:ns/quantum)
(quotient current-ms 10000)
)))
;; -- we define it to be the same as tai.
;; a different implemation of current-time-montonic
;; will require rewriting all of the time-monotonic converters,
;; of course.
;; SCSH portability: use time+ticks
(define (tm:current-time-monotonic)
(receive (seconds quanta) (time+ticks)
(make-time time-monotonic
(* quanta tm:ns/quantum)
(+ seconds (tm:leap-second-delta seconds))
)))
;; SCSH portability: thread time not available in scsh
(define (tm:current-time-thread)
(tm:time-error 'current-time 'unsupported-clock-type 'time-thread))
;; SCSH portability: use cpu-ticks/sec
(define (tm:current-time-process)
(let ((ticks/s (cpu-ticks/sec)))
(receive (userticks systicks childuserticks childsysticks) (process-times)
(make-time time-process
(* (remainder userticks ticks/s) (/ tm:nano ticks/s))
(quotient userticks ticks/s)))))
;; SCSH portability: GC time not available in scsh
(define (tm:current-time-gc)
(tm:time-error 'current-time 'unsupported-clock-type 'time-gc))
(define (current-time . clock-type)
(let ( (clock-type (:optional clock-type time-utc)) )
(cond
((eq? clock-type time-tai) (tm:current-time-tai))
((eq? clock-type time-utc) (tm:current-time-utc))
((eq? clock-type time-monotonic) (tm:current-time-monotonic))
((eq? clock-type time-thread) (tm:current-time-thread))
((eq? clock-type time-process) (tm:current-time-process))
((eq? clock-type time-gc) (tm:current-time-gc))
(else (tm:time-error 'current-time 'invalid-clock-type clock-type)))))
;; -- time resolution
;; this is the resolution of the clock in nanoseconds.
;; this will be implementation specific.
;; SCSH portability: use tm:ns/quantum and tm:nano
(define (time-resolution . clock-type)
(let ((clock-type (:optional clock-type time-utc)))
(cond
((eq? clock-type time-tai) tm:ns/quantum)
((eq? clock-type time-utc) tm:ns/quantum)
((eq? clock-type time-monotonic) tm:ns/quantum)
((eq? clock-type time-thread) tm:ns/quantum)
((eq? clock-type time-process) (/ tm:nano (cpu-ticks/sec)))
(else (tm:time-error 'time-resolution 'invalid-clock-type clock-type)))))
;; -- time comparisons
(define (tm:time-compare-check time1 time2 caller)
(if (or (not (and (time? time1) (time? time2)))
(not (eq? (time-type time1) (time-type time2))))
(tm:time-error caller 'incompatible-time-types #f)
#t))
(define (time=? time1 time2)
(tm:time-compare-check time1 time2 'time=?)
(and (= (time-second time1) (time-second time2))
(= (time-nanosecond time1) (time-nanosecond time2))))
(define (time>? time1 time2)
(tm:time-compare-check time1 time2 'time>?)
(or (> (time-second time1) (time-second time2))
(and (= (time-second time1) (time-second time2))
(> (time-nanosecond time1) (time-nanosecond time2)))))
(define (time<? time1 time2)
(tm:time-compare-check time1 time2 'time<?)
(or (< (time-second time1) (time-second time2))
(and (= (time-second time1) (time-second time2))
(< (time-nanosecond time1) (time-nanosecond time2)))))
(define (time>=? time1 time2)
(tm:time-compare-check time1 time2 'time>=?)
(or (>= (time-second time1) (time-second time2))
(and (= (time-second time1) (time-second time2))
(>= (time-nanosecond time1) (time-nanosecond time2)))))
(define (time<=? time1 time2)
(tm:time-compare-check time1 time2 'time<=?)
(or (<= (time-second time1) (time-second time2))
(and (= (time-second time1) (time-second time2))
(<= (time-nanosecond time1) (time-nanosecond time2)))))
;; -- time arithmetic
(define (tm:time->nanoseconds time)
(define (sign1 n)
(if (negative? n) -1 1))
(+ (* (time-second time) tm:nano)
(time-nanosecond time)))
(define (tm:nanoseconds->time time-type nanoseconds)
(make-time time-type
(remainder nanoseconds tm:nano)
(quotient nanoseconds tm:nano)))
(define (tm:nanoseconds->values nanoseconds)
(values (abs (remainder nanoseconds tm:nano))
(quotient nanoseconds tm:nano)))
(define (tm:time-difference time1 time2 time3)
(if (or (not (and (time? time1) (time? time2)))
(not (eq? (time-type time1) (time-type time2))))
(tm:time-error 'time-difference 'incompatible-time-types #f))
(set-time-type! time3 time-duration)
(if (time=? time1 time2)
(begin
(set-time-second! time3 0)
(set-time-nanosecond! time3 0))
(receive
(nanos secs)
(tm:nanoseconds->values (- (tm:time->nanoseconds time1)
(tm:time->nanoseconds time2)))
(set-time-second! time3 secs)
(set-time-nanosecond! time3 nanos)))
time3)
(define (time-difference time1 time2)
(tm:time-difference time1 time2 (make-time #f #f #f)))
(define (time-difference! time1 time2)
(tm:time-difference time1 time2 time1))
(define (tm:add-duration time1 duration time3)
(if (not (and (time? time1) (time? duration)))
(tm:time-error 'add-duration 'incompatible-time-types #f))
(if (not (eq? (time-type duration) time-duration))
(tm:time-error 'add-duration 'not-duration duration)
(let ( (sec-plus (+ (time-second time1) (time-second duration)))
(nsec-plus (+ (time-nanosecond time1) (time-nanosecond duration))) )
(let ((r (remainder nsec-plus tm:nano))
(q (quotient nsec-plus tm:nano)))
; (set-time-type! time3 (time-type time1))
(if (negative? r)
(begin
(set-time-second! time3 (+ sec-plus q -1))
(set-time-nanosecond! time3 (+ tm:nano r)))
(begin
(set-time-second! time3 (+ sec-plus q))
(set-time-nanosecond! time3 r)))
time3))))
(define (add-duration time1 duration)
(tm:add-duration time1 duration (make-time (time-type time1) #f #f)))
(define (add-duration! time1 duration)
(tm:add-duration time1 duration time1))
(define (tm:subtract-duration time1 duration time3)
(if (not (and (time? time1) (time? duration)))
(tm:time-error 'add-duration 'incompatible-time-types #f))
(if (not (eq? (time-type duration) time-duration))
(tm:time-error 'tm:subtract-duration 'not-duration duration)
(let ( (sec-minus (- (time-second time1) (time-second duration)))
(nsec-minus (- (time-nanosecond time1) (time-nanosecond duration))) )
(let ((r (remainder nsec-minus tm:nano))
(q (quotient nsec-minus tm:nano)))
(if (negative? r)
(begin
;;; SCSH portability: use binary -
(set-time-second! time3 (- (- sec-minus q) 1))
(set-time-nanosecond! time3 (+ tm:nano r)))
(begin
(set-time-second! time3 (- sec-minus q))
(set-time-nanosecond! time3 r)))
time3))))
(define (subtract-duration time1 duration)
(tm:subtract-duration time1 duration (make-time (time-type time1) #f #f)))
(define (subtract-duration! time1 duration)
(tm:subtract-duration time1 duration time1))
;; -- converters between types.
(define (tm:time-tai->time-utc! time-in time-out caller)
(if (not (eq? (time-type time-in) time-tai))
(tm:time-error caller 'incompatible-time-types time-in))
(set-time-type! time-out time-utc)
(set-time-nanosecond! time-out (time-nanosecond time-in))
(set-time-second! time-out (- (time-second time-in)
(tm:leap-second-neg-delta
(time-second time-in))))
time-out)
(define (time-tai->time-utc time-in)
(tm:time-tai->time-utc! time-in (make-time #f #f #f) 'time-tai->time-utc))
(define (time-tai->time-utc! time-in)
(tm:time-tai->time-utc! time-in time-in 'time-tai->time-utc!))
(define (tm:time-utc->time-tai! time-in time-out caller)
(if (not (eq? (time-type time-in) time-utc))
(tm:time-error caller 'incompatible-time-types time-in))
(set-time-type! time-out time-tai)
(set-time-nanosecond! time-out (time-nanosecond time-in))
(set-time-second! time-out (+ (time-second time-in)
(tm:leap-second-delta
(time-second time-in))))
time-out)
(define (time-utc->time-tai time-in)
(tm:time-utc->time-tai! time-in (make-time #f #f #f) 'time-utc->time-tai))
(define (time-utc->time-tai! time-in)
(tm:time-utc->time-tai! time-in time-in 'time-utc->time-tai!))
;; -- these depend on time-monotonic having the same definition as time-tai!
(define (time-monotonic->time-utc time-in)
(if (not (eq? (time-type time-in) time-monotonic))
(tm:time-error 'time-monotoinc->time-utc 'incompatible-time-types time-in))
(let ((ntime (copy-time time-in)))
(set-time-type! ntime time-tai)
(tm:time-tai->time-utc! ntime ntime 'time-monotonic->time-utc)))
(define (time-monotonic->time-utc! time-in)
(if (not (eq? (time-type time-in) time-monotonic))
(tm:time-error 'time-monotonic->time-utc! 'incompatible-time-types time-in))
(set-time-type! time-in time-tai)
(tm:time-tai->time-utc! time-in time-in 'time-monotonic->time-utc))
(define (time-monotonic->time-tai time-in)
(if (not (eq? (time-type time-in) time-monotonic))
(tm:time-error 'time-monotonic->time-tai 'incompatible-time-types time-in))
(let ((ntime (copy-time time-in)))
(set-time-type! ntime time-tai)
ntime))
(define (time-monotonic->time-tai! time-in)
(if (not (eq? (time-type time-in) time-monotonic))
(tm:time-error 'time-monotonic->time-tai! 'incompatible-time-types time-in))
(set-time-type! time-in time-tai)
time-in)
(define (time-utc->time-monotonic time-in)
(if (not (eq? (time-type time-in) time-utc))
(tm:time-error 'time-utc->time-monotonic 'incompatible-time-types time-in))
(let ((ntime (tm:time-utc->time-tai! time-in (make-time #f #f #f)
'time-utc->time-monotonic)))
(set-time-type! ntime time-monotonic)
ntime))
(define (time-utc->time-monotonic! time-in)
(if (not (eq? (time-type time-in) time-utc))
(tm:time-error 'time-utc->time-montonic! 'incompatible-time-types time-in))
(let ((ntime (tm:time-utc->time-tai! time-in time-in
'time-utc->time-monotonic!)))
(set-time-type! ntime time-monotonic)
ntime))
(define (time-tai->time-monotonic time-in)
(if (not (eq? (time-type time-in) time-tai))
(tm:time-error 'time-tai->time-monotonic 'incompatible-time-types time-in))
(let ((ntime (copy-time time-in)))
(set-time-type! ntime time-monotonic)
ntime))
(define (time-tai->time-monotonic! time-in)
(if (not (eq? (time-type time-in) time-tai))
(tm:time-error 'time-tai->time-monotonic! 'incompatible-time-types time-in))
(set-time-type! time-in time-monotonic)
time-in)
;; -- date structures
(define-record-type :date
(make-date nanosecond second minute hour day month year zone-offset)
date?
(nanosecond date-nanosecond set-date-nanosecond!)
(second date-second set-date-second!)
(minute date-minute set-date-minute!)
(hour date-hour set-date-hour!)
(day date-day set-date-day!)
(month date-month set-date-month!)
(year date-year set-date-year!)
(zone-offset date-zone-offset set-date-zone-offset!))
;; redefine setters
(define tm:set-date-nanosecond! set-date-nanosecond!)
(define tm:set-date-second! set-date-second!)
(define tm:set-date-minute! set-date-minute!)
(define tm:set-date-hour! set-date-hour!)
(define tm:set-date-day! set-date-day!)
(define tm:set-date-month! set-date-month!)
(define tm:set-date-year! set-date-year!)
(define tm:set-date-zone-offset! set-date-zone-offset!)
(define (set-date-second! date val)
(tm:time-error 'set-date-second! 'dates-are-immutable date))
(define (set-date-minute! date val)
(tm:time-error 'set-date-minute! 'dates-are-immutable date))
(define (set-date-day! date val)
(tm:time-error 'set-date-day! 'dates-are-immutable date))
(define (set-date-month! date val)
(tm:time-error 'set-date-month! 'dates-are-immutable date))
(define (set-date-year! date val)
(tm:time-error 'set-date-year! 'dates-are-immutable date))
(define (set-date-zone-offset! date val)
(tm:time-error 'set-date-zone-offset! 'dates-are-immutable date))
;; gives the julian day which starts at noon.
(define (tm:encode-julian-day-number day month year)
(let* ((a (quotient (- 14 month) 12))
;; SCSH portability: use binary -
(y (- (- (+ year 4800) a) (if (negative? year) -1 0)))
(m (- (+ month (* 12 a)) 3)))
(+ day
(quotient (+ (* 153 m) 2) 5)
(* 365 y)
(quotient y 4)
(- (quotient y 100))
(quotient y 400)
-32045)))
(define (tm:char-pos char str index len)
(cond
((>= index len) #f)
((char=? (string-ref str index) char)
index)
(else
(tm:char-pos char str (+ index 1) len))))
(define (tm:split-real r)
(if (integer? r)
(values r 0)
(let ((str (number->string (exact->inexact r))))
(let ((ppos (tm:char-pos #\. str 0 (string-length str))))
(if ppos
(values
(string->number (substring str 0 ppos))
(string->number (substring str (+ ppos 1) (string-length str))))
(values r 0))))))
;; gives the seconds/date/month/year
(define (tm:decode-julian-day-number jdn)
(let* ((days (truncate jdn))
(a (+ days 32044))
(b (quotient (+ (* 4 a) 3) 146097))
(c (- a (quotient (* 146097 b) 4)))
(d (quotient (+ (* 4 c) 3) 1461))
(e (- c (quotient (* 1461 d) 4)))
(m (quotient (+ (* 5 e) 2) 153))
(y (+ (* 100 b) d -4800 (quotient m 10))))
(values ; seconds date month year
(* (- jdn days) tm:sid)
(+ e (- (quotient (+ (* 153 m) 2) 5)) 1)
(+ m 3 (* -12 (quotient m 10)))
(if (>= 0 y) (- y 1) y))
))
;; relies on the fact that we named our time zone accessor
;; differently from MzScheme's....
;; This should be written to be OS specific.
;; SCSH portability: use scsh's DATE procedure
(define (tm:local-tz-offset)
(date:tz-secs (date)))
;; special thing -- ignores nanos
(define (tm:time->julian-day-number seconds tz-offset)
(+ (/ (+ seconds
tz-offset
tm:sihd)
tm:sid)
tm:tai-epoch-in-jd))
(define (tm:find proc l)
(if (null? l)
#f
(if (proc (car l))
#t
(tm:find proc (cdr l)))))
(define (tm:tai-before-leap-second? second)
(tm:find (lambda (x)
(= second (- (+ (car x) (cdr x)) 1)))
tm:leap-second-table))
(define (tm:time->date time tz-offset ttype)
(if (not (eq? (time-type time) ttype))
(tm:time-error 'time->date 'incompatible-time-types time))
(let* ( (offset (:optional tz-offset (tm:local-tz-offset))) )
(receive (secs date month year)
(tm:decode-julian-day-number
(tm:time->julian-day-number (time-second time) offset))
(let* ( (hours (quotient secs (* 60 60)))
(rem (remainder secs (* 60 60)))
(minutes (quotient rem 60))
(seconds (remainder rem 60)) )
(make-date (time-nanosecond time)
seconds
minutes
hours
date
month
year
offset)))))
(define (time-tai->date time . tz-offset)
(if (tm:tai-before-leap-second? (time-second time))
;; if it's *right* before the leap, we need to pretend to subtract a second ...
(let ((d (tm:time->date (subtract-duration! (time-tai->time-utc time) (make-time time-duration 0 1)) tz-offset time-utc)))
(tm:set-date-second! d 60)
d)
(tm:time->date (time-tai->time-utc time) tz-offset time-utc)))
(define (time-utc->date time . tz-offset)
(tm:time->date time tz-offset time-utc))
;; again, time-monotonic is the same as time tai
(define (time-monotonic->date time . tz-offset)
(tm:time->date time tz-offset time-monotonic))
(define (date->time-utc date)
(let ( (nanosecond (date-nanosecond date))
(second (date-second date))
(minute (date-minute date))
(hour (date-hour date))
(day (date-day date))
(month (date-month date))
(year (date-year date))
(offset (date-zone-offset date)) )
(let ( (jdays (- (tm:encode-julian-day-number day month year)
tm:tai-epoch-in-jd)) )
(make-time
time-utc
nanosecond
(+ (* (- jdays 1/2) 24 60 60)
(* hour 60 60)
(* minute 60)
second
(- offset))
))))
(define (date->time-tai d)
(if (= (date-second d) 60)
(subtract-duration! (time-utc->time-tai! (date->time-utc d)) (make-time time-duration 0 1))
(time-utc->time-tai! (date->time-utc d))))
(define (date->time-monotonic date)
(time-utc->time-monotonic! (date->time-utc date)))
(define (tm:leap-year? year)
(or (= (modulo year 400) 0)
(and (= (modulo year 4) 0) (not (= (modulo year 100) 0)))))
(define (leap-year? date)
(tm:leap-year? (date-year date)))
;; tm:year-day fixed: adding wrong number of days.
(define tm:month-assoc '((0 . 0) (1 . 31) (2 . 59) (3 . 90) (4 . 120)
(5 . 151) (6 . 181) (7 . 212) (8 . 243)
(9 . 273) (10 . 304) (11 . 334)))
(define (tm:year-day day month year)
(let ((days-pr (assoc (- month 1) tm:month-assoc)))
(if (not days-pr)
(tm:time-error 'date-year-day 'invalid-month-specification month))
(if (and (tm:leap-year? year) (> month 2))
(+ day (cdr days-pr) 1)
(+ day (cdr days-pr)))))
(define (date-year-day date)
(tm:year-day (date-day date) (date-month date) (date-year date)))
;; from calendar faq
(define (tm:week-day day month year)
(let* ((a (quotient (- 14 month) 12))
(y (- year a))
(m (+ month (* 12 a) -2)))
(modulo (+ day y (quotient y 4) (- (quotient y 100))
(quotient y 400) (quotient (* 31 m) 12))
7)))
(define (date-week-day date)
(tm:week-day (date-day date) (date-month date) (date-year date)))
(define (tm:days-before-first-week date day-of-week-starting-week)
(let* ( (first-day (make-date 0 0 0 0
1
1
(date-year date)
#f))
(fdweek-day (date-week-day first-day)) )
(modulo (- day-of-week-starting-week fdweek-day)
7)))
(define (date-week-number date day-of-week-starting-week)
(quotient (- (date-year-day date)
(tm:days-before-first-week date day-of-week-starting-week))
7))
(define (current-date . tz-offset)
(time-utc->date (current-time time-utc)
(:optional tz-offset (tm:local-tz-offset))))
;; given a 'two digit' number, find the year within 50 years +/-
(define (tm:natural-year n)
(let* ( (current-year (date-year (current-date)))
(current-century (* (quotient current-year 100) 100)) )
(cond
((>= n 100) n)
((< n 0) n)
((<= (- (+ current-century n) current-year) 50)
(+ current-century n))
(else
(+ (- current-century 100) n)))))
(define (date->julian-day date)
(let ( (nanosecond (date-nanosecond date))
(second (date-second date))
(minute (date-minute date))
(hour (date-hour date))
(day (date-day date))
(month (date-month date))
(year (date-year date))
(offset (date-zone-offset date)) )
(+ (tm:encode-julian-day-number day month year)
(- 1/2)
;; SCSH portability: use binary /
(+ (/ (/ (+ (* hour 60 60)
(* minute 60)
second
(/ nanosecond tm:nano))
tm:sid)
(- offset))))))
(define (date->modified-julian-day date)
(- (date->julian-day date)
4800001/2))
(define (time-utc->julian-day time)
(if (not (eq? (time-type time) time-utc))
(tm:time-error 'time-utc->julian-day 'incompatible-time-types time))
(+ (/ (+ (time-second time) (/ (time-nanosecond time) tm:nano))
tm:sid)
tm:tai-epoch-in-jd))
(define (time-utc->modified-julian-day time)
(- (time-utc->julian-day time)
4800001/2))
(define (time-tai->julian-day time)
(if (not (eq? (time-type time) time-tai))
(tm:time-error 'time-tai->julian-day 'incompatible-time-types time))
(+ (/ (+ (- (time-second time)
(tm:leap-second-delta (time-second time)))
(/ (time-nanosecond time) tm:nano))
tm:sid)
tm:tai-epoch-in-jd))
(define (time-tai->modified-julian-day time)
(- (time-tai->julian-day time)
4800001/2))
;; this is the same as time-tai->julian-day
(define (time-monotonic->julian-day time)
(if (not (eq? (time-type time) time-monotonic))
(tm:time-error 'time-monotonic->julian-day 'incompatible-time-types time))
(+ (/ (+ (- (time-second time)
(tm:leap-second-delta (time-second time)))
(/ (time-nanosecond time) tm:nano))
tm:sid)
tm:tai-epoch-in-jd))
(define (time-monotonic->modified-julian-day time)
(- (time-monotonic->julian-day time)
4800001/2))
(define (julian-day->time-utc jdn)
(let ( (nanosecs (* tm:nano tm:sid (- jdn tm:tai-epoch-in-jd))) )
(make-time time-utc
(remainder nanosecs tm:nano)
(floor (/ nanosecs tm:nano)))))
(define (julian-day->time-tai jdn)
(time-utc->time-tai! (julian-day->time-utc jdn)))
(define (julian-day->time-monotonic jdn)
(time-utc->time-monotonic! (julian-day->time-utc jdn)))
(define (julian-day->date jdn . tz-offset)
(let ((offset (:optional tz-offset (tm:local-tz-offset))))
(time-utc->date (julian-day->time-utc jdn) offset)))
(define (modified-julian-day->date jdn . tz-offset)
(let ((offset (:optional tz-offset (tm:local-tz-offset))))
(julian-day->date (+ jdn 4800001/2) offset)))
(define (modified-julian-day->time-utc jdn)
(julian-day->time-utc (+ jdn 4800001/2)))
(define (modified-julian-day->time-tai jdn)
(julian-day->time-tai (+ jdn 4800001/2)))
(define (modified-julian-day->time-monotonic jdn)
(julian-day->time-monotonic (+ jdn 4800001/2)))
(define (current-julian-day)
(time-utc->julian-day (current-time time-utc)))
(define (current-modified-julian-day)
(time-utc->modified-julian-day (current-time time-utc)))
;; returns a string rep. of number N, of minimum LENGTH,
;; padded with character PAD-WITH. If PAD-WITH if #f,
;; no padding is done, and it's as if number->string was used.
;; if string is longer than LENGTH, it's as if number->string was used.
(define (tm:padding n pad-with length)
(let* ( (str (number->string n))
(str-len (string-length str)) )
(if (or (> str-len length)
(not pad-with))
str
(let* ( (new-str (make-string length pad-with))
(new-str-offset (- (string-length new-str)
str-len)) )
(do ((i 0 (+ i 1)))
((>= i (string-length str)))
(string-set! new-str (+ new-str-offset i)
(string-ref str i)))
new-str))))
(define (tm:last-n-digits i n)
(abs (remainder i (expt 10 n))))
(define (tm:locale-abbr-weekday n)
(vector-ref tm:locale-abbr-weekday-vector n))
(define (tm:locale-long-weekday n)
(vector-ref tm:locale-long-weekday-vector n))
(define (tm:locale-abbr-month n)
(vector-ref tm:locale-abbr-month-vector n))
(define (tm:locale-long-month n)
(vector-ref tm:locale-long-month-vector n))
(define (tm:vector-find needle haystack comparator)
(let ((len (vector-length haystack)))
(define (tm:vector-find-int index)
(cond
((>= index len) #f)
((comparator needle (vector-ref haystack index)) index)
(else (tm:vector-find-int (+ index 1)))))
(tm:vector-find-int 0)))
(define (tm:locale-abbr-weekday->index string)
(tm:vector-find string tm:locale-abbr-weekday-vector string=?))
(define (tm:locale-long-weekday->index string)
(tm:vector-find string tm:locale-long-weekday-vector string=?))
(define (tm:locale-abbr-month->index string)
(tm:vector-find string tm:locale-abbr-month-vector string=?))
(define (tm:locale-long-month->index string)
(tm:vector-find string tm:locale-long-month-vector string=?))
;; do nothing.
;; Your implementation might want to do something...
;;
(define (tm:locale-print-time-zone date port)
(values))
;; Again, locale specific.
(define (tm:locale-am/pm hr)
(if (> hr 11) tm:locale-pm tm:locale-am))
(define (tm:tz-printer offset port)
(cond
((= offset 0) (display "Z" port))
((negative? offset) (display "-" port))
(else (display "+" port)))
(if (not (= offset 0))
(let ( (hours (abs (quotient offset (* 60 60))))
(minutes (abs (quotient (remainder offset (* 60 60)) 60))) )
(display (tm:padding hours #\0 2) port)
(display (tm:padding minutes #\0 2) port))))
;; A table of output formatting directives.
;; the first time is the format char.
;; the second is a procedure that takes the date, a padding character
;; (which might be #f), and the output port.
;;
;; SCSH portability: use #\space instead of #\Space and
;; (ascii->char 9) instead of #\Tab
(define char-tab (ascii->char 9))
(define tm:directives
(list
(cons #\~ (lambda (date pad-with port) (display #\~ port)))
(cons #\a (lambda (date pad-with port)
(display (tm:locale-abbr-weekday (date-week-day date))
port)))
(cons #\A (lambda (date pad-with port)
(display (tm:locale-long-weekday (date-week-day date))
port)))
(cons #\b (lambda (date pad-with port)
(display (tm:locale-abbr-month (date-month date))
port)))
(cons #\B (lambda (date pad-with port)
(display (tm:locale-long-month (date-month date))
port)))
(cons #\c (lambda (date pad-with port)
(display (date->string date tm:locale-date-time-format) port)))
(cons #\d (lambda (date pad-with port)
(display (tm:padding (date-day date)
#\0 2)
port)))
(cons #\D (lambda (date pad-with port)
(display (date->string date "~m/~d/~y") port)))
(cons #\e (lambda (date pad-with port)
(display (tm:padding (date-day date)
#\space 2)
port)))
(cons #\f (lambda (date pad-with port)
(if (> (date-nanosecond date)
tm:nano)
(display (tm:padding (+ (date-second date) 1)
pad-with 2)
port)
(display (tm:padding (date-second date)
pad-with 2)
port))
(receive (i f)
;;; SCSH portability: make use of / binary
(tm:split-real (/
(date-nanosecond date)
(* tm:nano 1.0)))
(let* ((ns (number->string f))
(le (string-length ns)))
(if (> le 2)
(begin
(display tm:locale-number-separator port)
(display (substring ns 2 le) port)))))))
(cons #\h (lambda (date pad-with port)
(display (date->string date "~b") port)))
(cons #\H (lambda (date pad-with port)
(display (tm:padding (date-hour date)
pad-with 2)
port)))
(cons #\I (lambda (date pad-with port)
(let ((hr (date-hour date)))
(if (> hr 12)
(display (tm:padding (- hr 12)
pad-with 2)
port)
(display (tm:padding hr
pad-with 2)
port)))))
(cons #\j (lambda (date pad-with port)
(display (tm:padding (date-year-day date)
pad-with 3)
port)))
(cons #\k (lambda (date pad-with port)
(display (tm:padding (date-hour date)
#\0 2)
port)))
(cons #\l (lambda (date pad-with port)
(let ((hr (if (> (date-hour date) 12)
(- (date-hour date) 12) (date-hour date))))
(display (tm:padding hr #\space 2)
port))))
(cons #\m (lambda (date pad-with port)
(display (tm:padding (date-month date)
pad-with 2)
port)))
(cons #\M (lambda (date pad-with port)
(display (tm:padding (date-minute date)
pad-with 2)
port)))
(cons #\n (lambda (date pad-with port)
(newline port)))
(cons #\N (lambda (date pad-with port)
(display (tm:padding (date-nanosecond date)
pad-with 7)
port)))
(cons #\p (lambda (date pad-with port)
(display (tm:locale-am/pm (date-hour date)) port)))
(cons #\r (lambda (date pad-with port)
(display (date->string date "~I:~M:~S ~p") port)))
(cons #\s (lambda (date pad-with port)
(display (time-second (date->time-utc date)) port)))
(cons #\S (lambda (date pad-with port)
(if (> (date-nanosecond date)
tm:nano)
(display (tm:padding (+ (date-second date) 1)
pad-with 2)
port)
(display (tm:padding (date-second date)
pad-with 2)
port))))
(cons #\t (lambda (date pad-with port)
(display char-tab port)))
(cons #\T (lambda (date pad-with port)
(display (date->string date "~H:~M:~S") port)))
(cons #\U (lambda (date pad-with port)
(if (> (tm:days-before-first-week date 0) 0)
(display (tm:padding (+ (date-week-number date 0) 1)
#\0 2) port)
(display (tm:padding (date-week-number date 0)
#\0 2) port))))
(cons #\V (lambda (date pad-with port)
(display (tm:padding (date-week-number date 1)
#\0 2) port)))
(cons #\w (lambda (date pad-with port)
(display (date-week-day date) port)))
(cons #\x (lambda (date pad-with port)
(display (date->string date tm:locale-short-date-format) port)))
(cons #\X (lambda (date pad-with port)
(display (date->string date tm:locale-time-format) port)))
(cons #\W (lambda (date pad-with port)
(if (> (tm:days-before-first-week date 1) 0)
(display (tm:padding (+ (date-week-number date 1) 1)
#\0 2) port)
(display (tm:padding (date-week-number date 1)
#\0 2) port))))
(cons #\y (lambda (date pad-with port)
(display (tm:padding (tm:last-n-digits
(date-year date) 2)
pad-with
2)
port)))
(cons #\Y (lambda (date pad-with port)
(display (date-year date) port)))
(cons #\z (lambda (date pad-with port)
(tm:tz-printer (date-zone-offset date) port)))
(cons #\Z (lambda (date pad-with port)
(tm:locale-print-time-zone date port)))
(cons #\1 (lambda (date pad-with port)
(display (date->string date "~Y-~m-~d") port)))
(cons #\2 (lambda (date pad-with port)
(display (date->string date "~k:~M:~S~z") port)))
(cons #\3 (lambda (date pad-with port)
(display (date->string date "~k:~M:~S") port)))
(cons #\4 (lambda (date pad-with port)
(display (date->string date "~Y-~m-~dT~k:~M:~S~z") port)))
(cons #\5 (lambda (date pad-with port)
(display (date->string date "~Y-~m-~dT~k:~M:~S") port)))
))
(define (tm:get-formatter char)
(let ( (associated (assoc char tm:directives)) )
(if associated (cdr associated) #f)))
(define (tm:date-printer date index format-string str-len port)
(if (>= index str-len)
(values)
(let ( (current-char (string-ref format-string index)) )
(if (not (char=? current-char #\~))
(begin
(display current-char port)
(tm:date-printer date (+ index 1) format-string str-len port))
(if (= (+ index 1) str-len) ; bad format string.
(tm:time-error 'tm:date-printer 'bad-date-format-string
format-string)
(let ( (pad-char? (string-ref format-string (+ index 1))) )
(cond
((char=? pad-char? #\-)
(if (= (+ index 2) str-len) ; bad format string.
(tm:time-error 'tm:date-printer 'bad-date-format-string
format-string)
(let ( (formatter (tm:get-formatter
(string-ref format-string
(+ index 2)))) )
(if (not formatter)
(tm:time-error 'tm:date-printer 'bad-date-format-string
format-string)
(begin
(formatter date #f port)
(tm:date-printer date (+ index 3)
format-string str-len port))))))
((char=? pad-char? #\_)
(if (= (+ index 2) str-len) ; bad format string.
(tm:time-error 'tm:date-printer 'bad-date-format-string
format-string)
(let ( (formatter (tm:get-formatter
(string-ref format-string
(+ index 2)))) )
(if (not formatter)
(tm:time-error 'tm:date-printer 'bad-date-format-string
format-string)
(begin
(formatter date #\space port)
(tm:date-printer date (+ index 3)
format-string str-len port))))))
(else
(let ( (formatter (tm:get-formatter
(string-ref format-string
(+ index 1)))) )
(if (not formatter)
(tm:time-error 'tm:date-printer 'bad-date-format-string
format-string)
(begin
(formatter date #\0 port)
(tm:date-printer date (+ index 2)
format-string str-len port))))))))))))
(define (date->string date . format-string)
(let ( (str-port (open-output-string))
(fmt-str (:optional format-string "~c")) )
(tm:date-printer date 0 fmt-str (string-length fmt-str) str-port)
(get-output-string str-port)))
(define (tm:char->int ch)
(cond
((char=? ch #\0) 0)
((char=? ch #\1) 1)
((char=? ch #\2) 2)
((char=? ch #\3) 3)
((char=? ch #\4) 4)
((char=? ch #\5) 5)
((char=? ch #\6) 6)
((char=? ch #\7) 7)
((char=? ch #\8) 8)
((char=? ch #\9) 9)
(else (tm:time-error 'string->date 'bad-date-template-string
(list "Non-integer character" ch )))))
;; read an integer upto n characters long on port; upto -> #f if any length
(define (tm:integer-reader upto port)
(define (accum-int port accum nchars)
(let ((ch (peek-char port)))
(if (or (eof-object? ch)
(not (char-numeric? ch))
(and upto (>= nchars upto )))
accum
(accum-int port (+ (* accum 10) (tm:char->int (read-char
port))) (+
nchars 1)))))
(accum-int port 0 0))
(define (tm:make-integer-reader upto)
(lambda (port)
(tm:integer-reader upto port)))
;; read *exactly* n characters and convert to integer; could be padded
(define (tm:integer-reader-exact n port)
(let ( (padding-ok #t) )
(define (accum-int port accum nchars)
(let ((ch (peek-char port)))
(cond
((>= nchars n) accum)
((eof-object? ch)
(tm:time-error 'string->date 'bad-date-template-string
"Premature ending to integer read."))
((char-numeric? ch)
(set! padding-ok #f)
(accum-int port (+ (* accum 10) (tm:char->int (read-char
port)))
(+ nchars 1)))
(padding-ok
(read-char port) ; consume padding
(accum-int port accum (+ nchars 1)))
(else ; padding where it shouldn't be
(tm:time-error 'string->date 'bad-date-template-string
"Non-numeric characters in integer read.")))))
(accum-int port 0 0)))
(define (tm:make-integer-exact-reader n)
(lambda (port)
(tm:integer-reader-exact n port)))
(define (tm:zone-reader port)
(let ( (offset 0)
(positive? #f) )
(let ( (ch (read-char port)) )
(if (eof-object? ch)
(tm:time-error 'string->date 'bad-date-template-string
(list "Invalid time zone +/-" ch)))
(if (or (char=? ch #\Z) (char=? ch #\z))
0
(begin
(cond
((char=? ch #\+) (set! positive? #t))
((char=? ch #\-) (set! positive? #f))
(else
(tm:time-error 'string->date 'bad-date-template-string
(list "Invalid time zone +/-" ch))))
(let ((ch (read-char port)))
(if (eof-object? ch)
(tm:time-error 'string->date 'bad-date-template-string
(list "Invalid time zone number" ch)))
(set! offset (* (tm:char->int ch)
10 60 60)))
(let ((ch (read-char port)))
(if (eof-object? ch)
(tm:time-error 'string->date 'bad-date-template-string
(list "Invalid time zone number" ch)))
(set! offset (+ offset (* (tm:char->int ch)
60 60))))
(let ((ch (read-char port)))
(if (eof-object? ch)
(tm:time-error 'string->date 'bad-date-template-string
(list "Invalid time zone number" ch)))
(set! offset (+ offset (* (tm:char->int ch)
10 60))))
(let ((ch (read-char port)))
(if (eof-object? ch)
(tm:time-error 'string->date 'bad-date-template-string
(list "Invalid time zone number" ch)))
(set! offset (+ offset (* (tm:char->int ch)
60))))
(if positive? offset (- offset)))))))
;; looking at a char, read the char string, run thru indexer, return index
(define (tm:locale-reader port indexer)
(let ( (string-port (open-output-string)) )
(define (read-char-string)
(let ((ch (peek-char port)))
(if (char-alphabetic? ch)
(begin (write-char (read-char port) string-port)
(read-char-string))
(get-output-string string-port))))
(let* ( (str (read-char-string))
(index (indexer str)) )
(if index index (tm:time-error 'string->date
'bad-date-template-string
(list "Invalid string for " indexer))))))
(define (tm:make-locale-reader indexer)
(lambda (port)
(tm:locale-reader port indexer)))
(define (tm:make-char-id-reader char)
(lambda (port)
(if (char=? char (read-char port))
char
(tm:time-error 'string->date
'bad-date-template-string
"Invalid character match."))))
;; A List of formatted read directives.
;; Each entry is a list.
;; 1. the character directive;
;; a procedure, which takes a character as input & returns
;; 2. #t as soon as a character on the input port is acceptable
;; for input,
;; 3. a port reader procedure that knows how to read the current port
;; for a value. Its one parameter is the port.
;; 4. a action procedure, that takes the value (from 3.) and some
;; object (here, always the date) and (probably) side-effects it.
;; In some cases (e.g., ~A) the action is to do nothing
(define tm:read-directives
(let ( (ireader4 (tm:make-integer-reader 4))
(ireader2 (tm:make-integer-reader 2))
(ireaderf (tm:make-integer-reader #f))
(eireader2 (tm:make-integer-exact-reader 2))
(eireader4 (tm:make-integer-exact-reader 4))
(locale-reader-abbr-weekday (tm:make-locale-reader
tm:locale-abbr-weekday->index))
(locale-reader-long-weekday (tm:make-locale-reader
tm:locale-long-weekday->index))
(locale-reader-abbr-month (tm:make-locale-reader
tm:locale-abbr-month->index))
(locale-reader-long-month (tm:make-locale-reader
tm:locale-long-month->index))
(char-fail (lambda (ch) #t))
(do-nothing (lambda (val object) (values)))
)
(list
(list #\~ char-fail (tm:make-char-id-reader #\~) do-nothing)
(list #\a char-alphabetic? locale-reader-abbr-weekday do-nothing)
(list #\A char-alphabetic? locale-reader-long-weekday do-nothing)
(list #\b char-alphabetic? locale-reader-abbr-month
(lambda (val object)
(tm:set-date-month! object val)))
(list #\B char-alphabetic? locale-reader-long-month
(lambda (val object)
(tm:set-date-month! object val)))
(list #\d char-numeric? ireader2 (lambda (val object)
(tm:set-date-day!
object val)))
(list #\e char-fail eireader2 (lambda (val object)
(tm:set-date-day! object val)))
(list #\h char-alphabetic? locale-reader-abbr-month
(lambda (val object)
(tm:set-date-month! object val)))
(list #\H char-numeric? ireader2 (lambda (val object)
(tm:set-date-hour! object val)))
(list #\k char-fail eireader2 (lambda (val object)
(tm:set-date-hour! object val)))
(list #\m char-numeric? ireader2 (lambda (val object)
(tm:set-date-month! object val)))
(list #\M char-numeric? ireader2 (lambda (val object)
(tm:set-date-minute!
object val)))
(list #\S char-numeric? ireader2 (lambda (val object)
(tm:set-date-second! object val)))
(list #\y char-fail eireader2
(lambda (val object)
(tm:set-date-year! object (tm:natural-year val))))
(list #\Y char-numeric? ireader4 (lambda (val object)
(tm:set-date-year! object val)))
(list #\z (lambda (c)
(or (char=? c #\Z)
(char=? c #\z)
(char=? c #\+)
(char=? c #\-)))
tm:zone-reader (lambda (val object)
(tm:set-date-zone-offset! object val)))
)))
(define (tm:string->date date index format-string str-len port template-string)
(define (skip-until port skipper)
(let ((ch (peek-char port)))
(if (eof-object? ch)
(tm:time-error 'string->date 'bad-date-format-string template-string)
(if (not (skipper ch))
(begin (read-char port) (skip-until port skipper))))))
(if (>= index str-len)
(begin
(values))
(let ( (current-char (string-ref format-string index)) )
(if (not (char=? current-char #\~))
(let ((port-char (read-char port)))
(if (or (eof-object? port-char)
(not (char=? current-char port-char)))
(tm:time-error 'string->date 'bad-date-format-string template-string))
(tm:string->date date (+ index 1) format-string str-len port template-string))
;; otherwise, it's an escape, we hope
(if (> (+ index 1) str-len)
(tm:time-error 'string->date 'bad-date-format-string template-string)
(let* ( (format-char (string-ref format-string (+ index 1)))
(format-info (assoc format-char tm:read-directives)) )
(if (not format-info)
(tm:time-error 'string->date 'bad-date-format-string template-string)
(begin
(let ((skipper (cadr format-info))
(reader (caddr format-info))
(actor (cadddr format-info)))
(skip-until port skipper)
(let ((val (reader port)))
(if (eof-object? val)
(tm:time-error 'string->date 'bad-date-format-string template-string)
(actor val date)))
(tm:string->date date (+ index 2) format-string str-len port template-string))))))))))
(define (string->date input-string template-string)
(define (tm:date-ok? date)
(and (date-nanosecond date)
(date-second date)
(date-minute date)
(date-hour date)
(date-day date)
(date-month date)
(date-year date)
(date-zone-offset date)))
(let ( (newdate (make-date 0 0 0 0 #f #f #f (tm:local-tz-offset))) )
(tm:string->date newdate
0
template-string
(string-length template-string)
(open-input-string input-string)
template-string)
(if (tm:date-ok? newdate)
newdate
(tm:time-error 'string->date 'bad-date-format-string (list "Incomplete date read. " newdate template-string)))))
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