(use srfi-19)
(use test)
(use format)
(use regex)
(declare (unit inteldate))
;; utility procedures to convert among
;; different ways to express date (inteldate, seconds since epoch, isodate)
;;
;; samples:
;; isodate -> "2016-01-01"
;; inteldate -> "16ww01.5"
;; seconds -> 1451631600
;; procedures provided:
;; ====================
;; seconds->isodate
;; seconds->inteldate
;;
;; isodate->seconds
;; isodate->inteldate
;;
;; inteldate->seconds
;; inteldate->isodate
;; srfi-19 used extensively; this doc is better tha the eggref:
;; http://srfi.schemers.org/srfi-19/srfi-19.html
;; Author: brandon.j.barclay@intel.com 16ww18.6
(define (date->seconds date)
(inexact->exact
(string->number
(date->string date "~s"))))
(define (seconds->isodate seconds)
(let* ((date (seconds->date seconds))
(result (date->string date "~Y-~m-~d")))
result))
(define (isodate->seconds isodate)
"Takes a string input of the form 'YY-MM-DD' or 'YYYY-MM-DD' and returns epoch time; for YY, assume after Y2K"
(let* ((numlist (map string->number (string-split isodate "-")))
(raw-year (car numlist))
(year (if (< raw-year 100) (+ raw-year 2000) raw-year))
(month (list-ref numlist 1))
(day (list-ref numlist 2))
(date (make-date 0 0 0 0 day month year))
(seconds (date->seconds date)))
seconds))
;; adapted from perl Intel::WorkWeek perl module
;; intel year consists of numbered weeks starting from week 1
;; week 1 is the week containing jan 1 of the year
;; days of week are numbered starting from 0 on sunday
;; intel year does not match calendar year in workweek 1
;; before jan1.
(define (seconds->inteldate-values seconds)
(define (date-difference->seconds d1 d2)
(- (date->seconds d1) (date->seconds d2)))
(let* ((thisdate (seconds->date seconds))
(thisdow (string->number (date->string thisdate "~w")))
(year (date-year thisdate))
;; intel workweek 1 begins on sunday of week containing jan1
(jan1 (make-date 0 0 0 0 1 1 year))
(jan1dow (date-week-day jan1))
(ww01 (date-subtract-duration jan1 (seconds->time (* 60 60 24 jan1dow))))
(ww01_delta_seconds (date-difference->seconds thisdate ww01))
(wwnum_initial (inexact->exact (add1 (floor (/ ww01_delta_seconds 24 3600 7) ))))
;; we could be in ww1 of next year
(this-saturday (seconds->date
(+ seconds
(* 60 60 24 (- 6 thisdow)))))
(this-week-ends-next-year?
(> (date-year this-saturday) year))
(intelyear
(if this-week-ends-next-year?
(add1 year)
year))
(intelweek
(if this-week-ends-next-year?
1
wwnum_initial)))
(values intelyear intelweek thisdow)))
(define (seconds->inteldate seconds)
(define (string-leftpad in width pad-char)
(let* ((unpadded-str (->string in))
(padlen_temp (- width (string-length unpadded-str)))
(padlen (if (< padlen_temp 0) 0 padlen_temp))
(padding
(fold conc ""
(map (lambda (x) (->string pad-char)) (iota padlen)))))
(conc padding unpadded-str)))
(define (zeropad num width)
(string-leftpad num width #:0))
(let-values (((intelyear intelweek day-of-week-num)
(seconds->inteldate-values seconds)))
(let ((intelyear-str
(zeropad
(->string
(if (> intelyear 1999)
(- intelyear 2000) intelyear))
2))
(intelweek-str
(zeropad (->string intelweek) 2))
(dow-str (->string day-of-week-num)))
(conc intelyear-str "ww" intelweek-str "." dow-str))))
(define (isodate->inteldate isodate)
(seconds->inteldate
(isodate->seconds isodate)))
(define (inteldate->seconds inteldate)
(let ((match (string-match "^(\\d+)ww(\\d+).(\\d)$" inteldate)))
(if
(not match)
#f
(let* (
(intelyear-raw (string->number (list-ref match 1)))
(intelyear (if (< intelyear-raw 100)
(+ intelyear-raw 2000)
intelyear-raw))
(intelww (string->number (list-ref match 2)))
(dayofweek (string->number (list-ref match 3)))
(day-of-seconds (* 60 60 24 ))
(week-of-seconds (* day-of-seconds 7))
;; get seconds at ww1.0
(new-years-date (make-date 0 0 0 0 1 1 intelyear))
(new-years-seconds
(date->seconds new-years-date))
(new-years-dayofweek (date-week-day new-years-date))
(ww1.0_seconds (- new-years-seconds
(* day-of-seconds
new-years-dayofweek)))
(workweek-adjustment (* week-of-seconds (sub1 intelww)))
(weekday-adjustment (* dayofweek day-of-seconds))
(result (+ ww1.0_seconds workweek-adjustment weekday-adjustment)))
result))))
(define (inteldate->isodate inteldate)
(seconds->isodate (inteldate->seconds inteldate)))
(define (inteldate-tests)
(test-group
"date conversion tests"
(let ((test-table
'(("16ww01.5" . "2016-01-01")
("16ww18.5" . "2016-04-29")
("1999ww33.5" . "1999-08-13")
("16ww18.4" . "2016-04-28")
("16ww18.3" . "2016-04-27")
("13ww01.0" . "2012-12-30")
("13ww52.6" . "2013-12-28")
("16ww53.3" . "2016-12-28"))))
(for-each
(lambda (test-pair)
(let ((inteldate (car test-pair))
(isodate (cdr test-pair)))
(test
(conc "(isodate->inteldate "isodate ") => "inteldate)
inteldate
(isodate->inteldate isodate))
(test
(conc "(inteldate->isodate "inteldate ") => "isodate)
isodate
(inteldate->isodate inteldate))))
test-table))))
;(inteldate-tests)