class OpenSSL::Config

def clear_comments(line)
  # FCOMMENT
  if m = line.match(/\A([\t\n\f ]*);.*\z/)
    return m[1]
  end
  # COMMENT
  scanned = []
  while m = line.match(/[#'"\\]/)
    scanned << m.pre_match
    c = m[0]
    line = m.post_match
    case c
    when '#'
      line = nil
      break
    when "'", '"'
      regexp = (c == "'") ? QUOTE_REGEXP_SQ : QUOTE_REGEXP_DQ
      scanned << c
      if m = line.match(regexp)
        scanned << m[0]
        line = m.post_match
      else
        scanned << line
        line = nil
        break
      end
    when "\\"
      scanned << c
      scanned << line.slice!(0, 1)
    else
      raise 'must not reaced'
    end
  end
  scanned << line
  scanned.join
end