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Merge pull request #3281 from nanoant/patch/lib-pure-times-hotfix

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times: Export & document countLeapYears/Years/Days
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Dominik Picheta 2015-09-03 21:37:35 +01:00
commit 4fefdb4d91
1 changed files with 17 additions and 13 deletions
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lib/pure/times.nim
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@ -1051,26 +1051,30 @@ proc parse*(value, layout: string): TimeInfo =
return info return info
# Leap year calculations are adapted from: # Leap year calculations are adapted from:
# from http://www.codeproject.com/Articles/7358/Ultra-fast-Algorithms-for-Working-with-Leap-Years # http://www.codeproject.com/Articles/7358/Ultra-fast-Algorithms-for-Working-with-Leap-Years
# The dayOfTheWeek procs are adapated from: # The dayOfTheWeek procs are adapated from:
# from http://stason.org/TULARC/society/calendars/2-5-What-day-of-the-week-was-2-August-1953.html # http://stason.org/TULARC/society/calendars/2-5-What-day-of-the-week-was-2-August-1953.html
# Note: for leap years, start date is assumed to be 1 AD. proc countLeapYears*(yearSpan: int): int =
# counts the number of leap years up to January 1st of a given year. ## Returns the number of leap years spanned by a given number of years.
# Keep in mind that if specified year is a leap year, the leap day ##
# has not happened before January 1st of that year. ## Note: for leap years, start date is assumed to be 1 AD.
proc countLeapYears(yearSpan: int): int = ## counts the number of leap years up to January 1st of a given year.
## Keep in mind that if specified year is a leap year, the leap day
## has not happened before January 1st of that year.
(((yearSpan - 1) / 4) - ((yearSpan - 1) / 100) + ((yearSpan - 1) / 400)).int (((yearSpan - 1) / 4) - ((yearSpan - 1) / 100) + ((yearSpan - 1) / 400)).int
proc countDays(yearSpan: int): int = proc countDays*(yearSpan: int): int =
## Returns the number of days spanned by a given number of years.
(yearSpan - 1) * 365 + countLeapYears(yearSpan) (yearSpan - 1) * 365 + countLeapYears(yearSpan)
proc countYears(daySpan: int): int = proc countYears*(daySpan: int): int =
# counts the number of years spanned by a given number of days. ## Returns the number of years spanned by a given number of days.
((daySpan - countLeapYears(daySpan div 365)) div 365) ((daySpan - countLeapYears(daySpan div 365)) div 365)
proc countYearsAndDays(daySpan: int): tuple[years: int, days: int] = proc countYearsAndDays*(daySpan: int): tuple[years: int, days: int] =
# counts the number of years spanned by a given number of days and the remainder as days. ## Returns the number of years spanned by a given number of days and the
## remainder as days.
let days = daySpan - countLeapYears(daySpan div 365) let days = daySpan - countLeapYears(daySpan div 365)
result.years = days div 365 result.years = days div 365
result.days = days mod 365 result.days = days mod 365