A.4 Initialization

This routine initializes the state structure for both the transmit and receive halves of some serial line. It must be called each time the line is brought up.

   void
   sl_compress_init(comp)
        struct slcompress *comp;
   {
        register u_int i;
        register struct cstate *tstate = comp->tstate;

        /*
         * Clean out any junk left from the last time line was used.
         */
        bzero((char *) comp, sizeof(*comp));
        /*
         * Link the transmit states into a circular list.
         */
        for (i = MAX_STATES - 1; i > 0; --i) {
             tstate[i].cs_id = i;
             tstate[i].cs_next = &tstate[i - 1];
        }
        tstate[0].cs_next = &tstate[MAX_STATES - 1];
        tstate[0].cs_id = 0;
        comp->last_cs = &tstate[0];
        /*
         * Make sure we don't accidentally do CID compression
         * (assumes MAX_STATES < 255).
         */
        comp->last_recv = 255;
        comp->last_xmit = 255;
   }