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(* TextIO -- 1995-11-22, 1996-07-07, 2000-03-15; no positions etc. yet *) type elem = Char.chartype vector = stringtype pos = int prim_val create_string_ : int -> string                 = 1 "create_string";prim_val nth_char_      : string -> int -> char         = 2 "get_nth_char";prim_val set_nth_char_  : string -> int -> char -> unit = 3 "set_nth_char";prim_val blit_string_   : string -> int -> string -> int -> int -> unit                                                         = 5 "blit_string"; fun sub_string_ s start len =  let val res = create_string_ len  in blit_string_ s start res 0 len; res end; (* Caml Light "channels" *) prim_type in_channel and out_channel; prim_val open_descriptor_in : int -> in_channel = 1 "open_descriptor";        (* [open_descriptor_in fd] returns a buffered input channel           reading from the file descriptor [fd]. The file descriptor [fd]           must have been previously opened for reading, else the behavior is	   undefined. *) prim_val open_descriptor_out : int -> out_channel = 1 "open_descriptor";        (* [open_descriptor_out fd] returns a buffered output channel           writing to the file descriptor [fd]. The file descriptor [fd]           must have been previously opened for writing, else the behavior is	   undefined. *) prim_val input_char_ : in_channel -> char = 1 "input_char"        (* Read one character from the given input channel.           Raise [Size] if there are no more characters to read. *) prim_val output_char_ : out_channel -> char -> unit = 2 "output_char"; prim_val caml_seek_in : in_channel -> int -> unit = 2 "seek_in"        (* [seek_in chan pos] sets the current reading position to [pos]           for channel [chan]. *) prim_val caml_pos_in : in_channel -> int = 1 "pos_in";        (* Return the current reading position for the given channel. *) prim_val caml_close_in : in_channel -> unit = 1 "close_in"        (* Close the given channel. Anything can happen if any of the           above functions is called on a closed channel. *) type file_perm = int; datatype open_flag =    O_APPEND                       (* `open' for appending *)  | O_BINARY                       (* `open' in binary mode *)      | O_CREAT                        (* create the file if nonexistent *)  | O_EXCL                         (* fails if the file exists *)  | O_RDONLY                       (* `open' read-only *)  | O_RDWR                         (* `open' for reading and writing *)  | O_TEXT                         (* `open' in text mode *)  | O_TRUNC                        (* truncate the file to 0 if it exists *)  | O_WRONLY                       (* `open' write-only *); prim_val sys_open :  string -> open_flag list -> file_perm -> int = 3 "sys_open"        (* Open a file. The second argument is the opening mode.           The third argument is the permissions to use if the file           must be created. The result is a file descriptor opened on the           file. *)prim_val sys_close :  int -> unit = 1 "sys_close"        (* Close a file descriptor. *) val caml_std_in  = open_descriptor_in 0and caml_std_out = open_descriptor_out 1and caml_std_err = open_descriptor_out 2; prim_val fast_input :  in_channel -> string -> int -> int -> int = 4 "input";prim_val fast_input_nonblocking :  in_channel -> string -> int -> int -> int option = 4 "input_nonblocking";prim_val fast_output :  out_channel -> string -> int -> int -> unit = 4 "output"; fun caml_open_in_gen mode rights filename =  open_descriptor_in (sys_open filename mode rights); val caml_open_in = caml_open_in_gen [O_RDONLY, O_TEXT] 0and caml_open_in_bin = caml_open_in_gen [O_RDONLY, O_BINARY] 0; fun open_out_gen mode rights filename =  open_descriptor_out(sys_open filename mode rights); prim_val s_irall : file_perm = 0 "s_irall";prim_val s_iwall : file_perm = 0 "s_iwall"; val caml_open_out =  open_out_gen [O_WRONLY, O_TRUNC, O_CREAT, O_TEXT] (s_irall + s_iwall)and caml_open_out_bin =  open_out_gen [O_WRONLY, O_TRUNC, O_CREAT, O_BINARY] (s_irall + s_iwall); prim_val caml_flush : out_channel -> unit = 1 "flush"        (* Flush the buffer associated with the given output channel,           performing all pending writes on that channel.           Interactive programs must be careful about flushing [std_out]           at the right times. *) fun caml_output_string channel s =    fast_output channel s 0 (size s); prim_val caml_close_out : out_channel -> unit = 1 "close_out"        (* Close the given channel, flushing all buffered write operations.	   The behavior is unspecified if any of the above functions is	   called on a closed channel. *) fun try_input_char_ ic =  SOME (input_char_ ic)  handle Size => NONE; (* Moscow ML imperative Text I/O *) type instream  = { closed: bool, ic: in_channel,  name : string} ref;type outstream = { closed: bool, oc: out_channel, name : string} ref; val stdIn  : instream  =     ref { closed=false, ic=caml_std_in,  name = "<stdIn>"  }and stdOut : outstream =     ref { closed=false, oc=caml_std_out, name = "<stdOut>" }and stdErr : outstream =     ref { closed=false, oc=caml_std_err, name = "<stdErr>" }; fun raiseIo fcn nam exn =     raise Io {function = fcn, name = nam, cause = exn}; fun raiseClosed fcn nam =     raiseIo fcn nam (Fail "Stream is closed"); fun openIn s =  ref {closed=false, ic=caml_open_in s, name = s}  handle exn as SysErr _ => raiseIo "openIn" s exn; fun closeIn (is as ref {closed, ic, name}) =  if closed then ()   else (caml_close_in ic;	is := { closed=true, ic=ic, name=name }); fun input1 (is as ref {closed, ic, name}) =    if closed then NONE     else 	SOME (input_char_ ic)	handle Size => NONE; fun input (is as ref {closed, ic, name}) =    if closed then ""     else let val buff = create_string_ 60 	 in case fast_input ic buff 0 60 of	     0 => ""	   | m => sub_string_ buff 0 m	 end; fun inputNoBlock (is as ref {closed, ic, name}) =    if closed then SOME ""     else let val buff = create_string_ 60 	 in case fast_input_nonblocking ic buff 0 60 of	     NONE   => NONE 	   | SOME 0 => SOME ""	   | SOME m => SOME (sub_string_ buff 0 m)	 end; fun inputN (is as ref {closed, ic, name}, n) =    if n < 0 orelse n > String.maxSize then raise Size    else if closed then ""     else let val buff = create_string_ n	     fun loop k =		 if k = n then buff		 else		     case fast_input ic buff k (n-k) of			 0 => sub_string_ buff 0 k		       | m => loop (k+m)	 in loop 0 end; fun inputAll (is as ref {closed, ic, name}) =  if closed then "" else  let val max = ref 127      val tmp = ref (create_string_ (!max))      fun realloc () =	  let val newmax = if !max = String.maxSize then raise Size			   else if 2 * !max >= String.maxSize then String.maxSize			   else 2 * !max	      val newtmp = create_string_ newmax	  in 	      blit_string_ (!tmp) 0 newtmp 0 (!max);	      max := newmax;	      tmp := newtmp	  end      (* Don't read more than runtime/io.IO_BUFFER_SIZE characters:  *)      fun chunksize sz = if sz > 4096 then 4096 else sz      fun h len =	  case fast_input ic (!tmp) len (chunksize (!max - len)) of	      0 => sub_string_ (!tmp) 0 len	    | m => (if !max - (len + m) < 127 then realloc () else ();		    h (len + m));  in h 0 end; type cs = int (* character source state *) fun scanStream scan (instrm as ref {closed, ic, name}) =    let prim_eqtype array_	prim_val array_  : int -> array_                 = 1 "create_string";	prim_val sub_    : array_ -> int -> char         = 2 "get_nth_char";	prim_val update_ : array_ -> int -> char -> unit = 3 "set_nth_char";         val buf  = array_ 512		(* characters recently read     *)	val read = ref 0		(* number of characters read    *)	fun getc charno =	    if charno < !read then		(* already read         *)		if charno >= !read - 512 then	(* still in buffer      *)		    SOME(sub_ buf (charno mod 512), charno+1)		else				(* no longer in buffer  *)		    raise Fail "scanStream: backtracking too far"	    else	        (* charno = !read; read a new character *)		if closed then NONE		else (let val c = input_char_ ic		      in (update_ buf (charno mod 512) c;			  read := !read + 1;			  SOME(c, charno+1))		      end handle Size => NONE)    in case scan getc 0 of        NONE         => NONE      | SOME(res, _) => SOME res    end; (* fun inputNoBlock (is : instream) : vector option =    raise Fail "not implemented";*) fun lookahead (is as ref {closed, ic, name}) =  if closed then NONE else  let val pos = caml_pos_in ic in      case try_input_char_ ic of	  NONE            => NONE	| res as (SOME c) => (caml_seek_in ic pos; res)  end; fun endOfStream is = (lookahead is = NONE); fun openAppend (s : string) : outstream =  ref { closed=false,        oc=open_out_gen [O_WRONLY, O_APPEND, O_CREAT, O_TEXT]                        (s_irall + s_iwall) s,	name=s}  handle exn as SysErr _ => raiseIo "openAppend" s exn; fun output (os as ref {closed, oc, name}, s) =    if closed then	raiseClosed "output" name    else	(caml_output_string oc s;	 if os = stdErr then caml_flush oc else ()); fun outputSubstr (os as ref {closed, oc, name}, sus : substring) =    let prim_val substrToTrip : substring -> string * int * int = 1 "identity"        val (s, i, n) = substrToTrip sus    in if closed then	  raiseClosed "outputSubstr" name       else	   (fast_output oc s i n;	    if os = stdErr then caml_flush oc else ())    end; fun output1 (os as ref {closed, oc, name}, c) =    if closed then	raiseClosed "output1" name    else	(output_char_ oc c;	 if os = stdErr then caml_flush oc else ()); fun inputLine (is as ref {closed, ic, name}) =  if closed then "" else  let val max = ref 127      val tmp = ref (create_string_ (!max))      fun realloc () =	  let val newmax = if !max = String.maxSize then raise Size			   else if 2 * !max >= String.maxSize then String.maxSize			   else 2 * !max	      val newtmp = create_string_ newmax	  in 	      blit_string_ (!tmp) 0 newtmp 0 (!max);	      max := newmax;	      tmp := newtmp	  end      fun h len =	  (if len >= !max then realloc () else ();	   case try_input_char_ ic of	       NONE   => (set_nth_char_ (!tmp) len #"\n"; 			  sub_string_ (!tmp) 0 (len+1))	     | SOME c => (set_nth_char_ (!tmp) len c;			  if c = #"\n" then sub_string_ (!tmp) 0 (len+1) 			               else h (len+1)))  in if endOfStream is then "" else h 0 end; fun openOut (s : string) : outstream =    ref {closed=false, oc=caml_open_out s, name=s}    handle exn as SysErr _ => raiseIo "openOut" s exn; fun closeOut (os as ref {closed, oc, name}) =    if closed then ()     else (caml_close_out oc; 	  os := {closed = true, oc=oc, name=name}; 	  ()); fun flushOut (os as ref {closed, oc, name}) =  if closed then      raiseClosed "flushOut" name  else      caml_flush oc; fun print s = (output(stdOut, s); flushOut stdOut);