source: trunk/minix/lib/ack/libm2/Terminal.mod@ 20

#
(*
  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
  See the copyright notice in the ACK home directory, in the file "Copyright".
*)

(*$R-*)
IMPLEMENTATION MODULE Terminal;
(*
  Module:       Input/Output to/from terminals
  Author:       Ceriel J.H. Jacobs
  Version:      $Header: /cvsup/minix/src/lib/ack/libm2/Terminal.mod,v 1.1 2005/10/10 15:27:46 beng Exp $

  Implementation for Unix.
*)
  FROM  SYSTEM IMPORT   ADR;
#ifdef __USG
  FROM  Unix IMPORT     read, write, open, fcntl;
#else
  FROM  Unix IMPORT     read, write, open, ioctl;
#endif
  VAR fildes: INTEGER;
      unreadch: CHAR;
      unread: BOOLEAN;
      tty: ARRAY[0..8] OF CHAR;

  PROCEDURE Read(VAR ch: CHAR);
  BEGIN
        IF unread THEN
                ch := unreadch;
                unread := FALSE
        ELSE
                IF read(fildes, ADR(ch), 1) < 0 THEN
                        ;
                END;
        END;
        unreadch := ch;
  END Read;

  PROCEDURE BusyRead(VAR ch: CHAR);
    VAR l: INTEGER;
  BEGIN
        IF unread THEN
                ch := unreadch;
                unread := FALSE
        ELSE
#ifdef __USG
                l := fcntl(fildes, (*FGETFL*) 3, 0);
                IF fcntl(fildes,
                              (* FSETFL *) 4,
                              l + (*ONDELAY*) 2) < 0 THEN
                        ;
                END;
                IF read(fildes, ADR(ch), 1) = 0 THEN
                        ch := 0C;
                ELSE
                        unreadch := ch;
                END;
                IF fcntl(fildes, (*FSETFL*)4, l) < 0 THEN
                        ;
                END;
#else
#ifdef __BSD4_2
                IF ioctl(fildes, INTEGER(ORD('f')*256+127+4*65536+40000000H), ADR(l)) < 0 THEN
#else
                IF ioctl(fildes, INTEGER(ORD('f')*256+127), ADR(l)) < 0 THEN
#endif
                        ;
                END;

                IF l = 0 THEN
                        ch := 0C;
                ELSE
                        IF read(fildes, ADR(ch), 1) < 0 THEN
                                ;
                        END;
                        unreadch := ch;
                END;
#endif
        END;
  END BusyRead; 

  PROCEDURE ReadAgain;
  BEGIN
        unread := TRUE;
  END ReadAgain;

  PROCEDURE Write(ch: CHAR);
  BEGIN
        IF write(fildes, ADR(ch), 1) < 0 THEN
                ;
        END;
  END Write;

  PROCEDURE WriteLn;
  BEGIN
        Write(12C);
  END WriteLn;

  PROCEDURE WriteString(s: ARRAY OF CHAR);
    VAR i: CARDINAL;
  BEGIN
        i := 0;
        WHILE (i <= HIGH(s)) & (s[i] # 0C) DO
                Write(s[i]);
                INC(i)
        END
  END WriteString;

BEGIN
        tty := "/dev/tty";
        fildes := open(ADR(tty), 2);
        unread := FALSE;
END Terminal.