Filename_new.Win32.quote

let quote s =
    let l = String.length s in
    let b = Buffer.create (l + 20) in
    Buffer.add_char b '\"';
    let rec loop i =
      if i = l then Buffer.add_char b '\"' else
      match s.[i] with
      | '\"' -> loop_bs 0 i;
      | '\\' -> loop_bs 0 i;
      | c    -> Buffer.add_char b c; loop (i+1);
    and loop_bs n i =
      if i = l then begin
        Buffer.add_char b '\"';
        add_bs n;
      end else begin
        match s.[i] with
        | '\"' -> add_bs (2*n+1); Buffer.add_char b '\"'; loop (i+1);
        | '\\' -> loop_bs (n+1) (i+1);
        | _c    -> add_bs n; loop i
      end
    and add_bs n = for j = 1 to n do Buffer.add_char b '\\'; done
    in
    loop 0;
    Buffer.contents b