parse_offset (TZInfo::TZDataParser)

    # File lib/tzinfo/tzdataparser.rb, line 147
        def self.parse_offset(offset)
          raise "Invalid time: #{offset}" if offset !~ /^(-)?([0-9]+)(:([0-9]+)(:([0-9]+))?)?$/

          negative = !$1.nil?
          hour = $2.to_i
          minute = $4.nil? ? 0 : $4.to_i
          second = $6.nil? ? 0 : $6.to_i

          seconds = hour
          seconds = seconds * 60
          seconds = seconds + minute
          seconds = seconds * 60
          seconds = seconds + second
          seconds = -seconds if negative
          seconds
        end