let to_stringstream strm =
  Stream2.map (fun line -> line ^ "\n") strm

let to_file path strm =
  let chan = open_out_gen [Open_creat; Open_trunc; Open_wronly] 0o0644 path in
  Stream.iter (output_string chan) (to_stringstream strm);
  close_out chan

(** Return a stream of the lines of a file *)
let of_file path =
  let chan = open_in path in
  Stream.from (fun _ ->
		 try Some (input_line chan)
		 with
		   End_of_file -> close_in chan; None
		 | exn -> close_in chan; raise exn)

(** Turn a stream of strings into a stream of lines.  The buffer size
    is chosen to be the same as the number returned by Channel.line_buf
    but it doesn't need to be. *)
let of_stringstream ?(bufsize=4096) strm =
  let buf = Charqueue.create bufsize	(* Next line is constructed here *)
  and inb = Charqueue.make "" in	(* Holds unused input *)
  Stream.from
    (fun n ->
       let rec loop () =
	 try
	   if Charqueue.empty inb then Charqueue.replace inb (Stream.next strm);
	   let eol = Charqueue.index inb '\n' in
	   Charqueue.add_string buf (Charqueue.head inb eol);
	   Charqueue.discard inb (eol + 1);		(* Discard newline *)
	   let line = Charqueue.contents buf in
	   Charqueue.clear buf;
	   Some line
	 with
	   Not_found -> begin
	     (* No newline in input buffer *)
	     try
	       (* No newlines in input buffer, append it to buffer *)
	       Charqueue.add_string buf (Charqueue.contents inb);
	       Charqueue.clear inb;
	       loop ()
	     with
	       Invalid_argument "Charqueue.extend" ->
		 (* Too much text without finding eol *)
		 prerr_endline "Line too long, splitting";
		 let line = Charqueue.contents buf in
		 Charqueue.clear buf;
		 Some line
	   end
	 | Invalid_argument "Charqueue.extend" ->
	     (* Found eol, but resulting line was too long *)
	     prerr_endline "Line too long, splitting";
	     let line = Charqueue.contents buf in
	     Charqueue.clear buf;
	     Some line
	 | Stream.Failure ->
	     (* End of input *)
	     if Charqueue.empty buf
	     then None
	     else begin
	       let line = Charqueue.contents buf in
	       Charqueue.clear buf;
	       Some line
	     end in
       loop ())