_rfc2822

# File lib/date/format.rb, line 1174
  def self._rfc2822(str) # :nodoc:
    if /\A\s*(?:(?:#{Format::ABBR_DAYS.keys.join('|')})\s*,\s+)?
        \d{1,2}\s+
        (?:#{Format::ABBR_MONTHS.keys.join('|')})\s+
        -?(\d{2,})\s+ # allow minus, anyway
        \d{2}:\d{2}(:\d{2})?\s*
        (?:[-+]\d{4}|ut|gmt|e[sd]t|c[sd]t|m[sd]t|p[sd]t|[a-ik-z])\s*\z/ox =~ str
      e = _parse(str, false)
      if $1.size < 4
        if e[:year] < 50
          e[:year] += 2000
        elsif e[:year] < 1000
          e[:year] += 1900
        end
      end
      e
    end
  end