module Bunto::Utils::WinTZ
Public Instance Methods
calculate(timezone)
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Public: Calculate the Timezone for Windows when the config file has a defined
'timezone' key.
timezone - the IANA Time Zone specified in “_config.yml”
Returns a string that ultimately re-defines ENV in Windows
# File lib/bunto/utils/win_tz.rb, line 12 def calculate(timezone) External.require_with_graceful_fail("tzinfo") tz = TZInfo::Timezone.get(timezone) difference = Time.now.to_i - tz.now.to_i # # POSIX style definition reverses the offset sign. # e.g. Eastern Standard Time (EST) that is 5Hrs. to the 'west' of Prime Meridian # is denoted as: # EST+5 (or) EST+05:00 # Reference: http://www.gnu.org/software/libc/manual/html_node/TZ-Variable.html sign = difference < 0 ? "-" : "+" offset = sign == "-" ? "+" : "-" unless difference.zero? # # convert the difference (in seconds) to hours, as a rational number, and perform # a modulo operation on it. modulo = modulo_of(rational_hour(difference)) # # Format the hour as a two-digit number. # Establish the minutes based on modulo expression. hh = format("%02d", absolute_hour(difference).ceil) mm = modulo.zero? ? "00" : "30" Bunto.logger.debug "Timezone:", "#{timezone} #{offset}#{hh}:#{mm}" # # Note: The 3-letter-word below doesn't have a particular significance. "WTZ#{sign}#{hh}:#{mm}" end
Private Instance Methods
absolute_hour(seconds)
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Private: Convert given seconds to an hour as an absolute number.
seconds - supplied as an integer, it is converted to its absolute. 3600 - no. of seconds in an hour.
Returns an integer.
# File lib/bunto/utils/win_tz.rb, line 58 def absolute_hour(seconds) seconds.abs/3600 end
modulo_of(fraction)
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Private: Perform a modulo operation on a given fraction.
fraction - supplied as a rational number, its numerator is divided
by its denominator and the remainder returned.
Returns an integer.
# File lib/bunto/utils/win_tz.rb, line 68 def modulo_of(fraction) fraction.numerator % fraction.denominator end
rational_hour(seconds)
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Private: Convert given seconds to an hour as a rational number.
seconds - supplied as an integer, it is converted to a rational number. 3600 - no. of seconds in an hour.
Returns a rational number.
# File lib/bunto/utils/win_tz.rb, line 48 def rational_hour(seconds) seconds.to_r/3600 end