module RDoc::Text

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.strip
end