wrap

# File lib/rdoc/markup/to_html.rb, line 136
  def wrap(txt, line_len = 76)
    res = []
    sp = 0
    ep = txt.length

    while sp < ep
      # scan back for a space
      p = sp + line_len - 1
      if p >= ep
        p = ep
      else
        while p > sp and txt[p] != \s\
          p -= 1
        end
        if p <= sp
          p = sp + line_len
          while p < ep and txt[p] != \s\
            p += 1
          end
        end
      end
      res << txt[sp...p] << "\n"
      sp = p
      sp += 1 while sp < ep and txt[sp] == \s\
    end

    res.join
  end