(************************************************************
   cmp.ml		Created      : Wed Dec 27 12:55:53 2006
  			Last modified: Wed Dec 27 21:21:45 2006
  Compile: ocamlopt cmp.ml -o cmp #
  FTP Directory: sources/ocaml #
************************************************************)
(**

  @author Takashi Masuyama <mamewo@dk9.so-net.ne.jp>

*)

type t = Same | Differ of int * int

let compare in1 in2 =
  let rec iter charnum linenum =
    match (Stream.peek in1), (Stream.peek in2) with
      (Some b1), (Some b2) ->
	if b1 = b2 then
	  begin
	    Stream.junk in1;
	    Stream.junk in2;
	    iter (charnum+1) (if b1 = '\n' then (linenum+1) else linenum)
	  end
	else Differ (charnum, linenum)
    | None, None -> Same
    | _ -> Differ (charnum, linenum) in
  iter 1 1

let _ =
  if Array.length Sys.argv <> 3 then
    begin
      prerr_endline "cmp FILE1 FILE2";
      exit 2
    end;
  let file1 = Sys.argv.(1) in
  let file2 = Sys.argv.(2) in
  let in_channel1 = open_in file1 in
  let in_channel2 = open_in file2 in
  let in_stream1 = Stream.of_channel in_channel1 in
  let in_stream2 = Stream.of_channel in_channel2 in
  let result = compare in_stream1 in_stream2 in
  close_in in_channel1;
  close_in in_channel2;
  match result with
    Same -> exit 0
  | Differ (charnum, linenum) -> 
      begin
	Printf.fprintf stderr "%s %s differ: char %d, line %d\n" file1 file2 charnum linenum;
	exit 1
      end

(*
 * Local Variables:
 *  namazu-default-dir:"/home/tak/.indexes/ocaml"
 * End:
 *)