xdr_rec.c

Axis 221 camera embedded programing interface

	break;
      }
  return (u_int) pos;
}

static bool_t
xdrrec_setpos (XDR *xdrs, u_int pos)
{
  RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
  u_int currpos = xdrrec_getpos (xdrs);
  int delta = currpos - pos;
  caddr_t newpos;

  if ((int) currpos != -1)
    switch (xdrs->x_op)
      {

      case XDR_ENCODE:
	newpos = rstrm->out_finger - delta;
	if (newpos > (caddr_t) rstrm->frag_header &&
	    newpos < rstrm->out_boundry)
	  {
	    rstrm->out_finger = newpos;
	    return TRUE;
	  }
	break;

      case XDR_DECODE:
	newpos = rstrm->in_finger - delta;
	if ((delta < (int) (rstrm->fbtbc)) &&
	    (newpos <= rstrm->in_boundry) &&
	    (newpos >= rstrm->in_base))
	  {
	    rstrm->in_finger = newpos;
	    rstrm->fbtbc -= delta;
	    return TRUE;
	  }
	break;

      default:
	break;
      }
  return FALSE;
}

static int32_t *
xdrrec_inline (XDR *xdrs, int len)
{
  RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
  int32_t *buf = NULL;

  switch (xdrs->x_op)
    {

    case XDR_ENCODE:
      if ((rstrm->out_finger + len) <= rstrm->out_boundry)
	{
	  buf = (int32_t *) rstrm->out_finger;
	  rstrm->out_finger += len;
	}
      break;

    case XDR_DECODE:
      if ((len <= rstrm->fbtbc) &&
	  ((rstrm->in_finger + len) <= rstrm->in_boundry))
	{
	  buf = (int32_t *) rstrm->in_finger;
	  rstrm->fbtbc -= len;
	  rstrm->in_finger += len;
	}
      break;

    default:
      break;
    }
  return buf;
}

static void
xdrrec_destroy (XDR *xdrs)
{
  RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;

  mem_free (rstrm->the_buffer,
	    rstrm->sendsize + rstrm->recvsize + BYTES_PER_XDR_UNIT);
  mem_free ((caddr_t) rstrm, sizeof (RECSTREAM));
}

static bool_t
xdrrec_getint32 (XDR *xdrs, int32_t *ip)
{
  RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
  int32_t *bufip = (int32_t *) rstrm->in_finger;
  int32_t mylong;

  /* first try the inline, fast case */
  if (rstrm->fbtbc >= BYTES_PER_XDR_UNIT &&
      rstrm->in_boundry - (char *) bufip >= BYTES_PER_XDR_UNIT)
    {
      *ip = ntohl (*bufip);
      rstrm->fbtbc -= BYTES_PER_XDR_UNIT;
      rstrm->in_finger += BYTES_PER_XDR_UNIT;
    }
  else
    {
      if (!xdrrec_getbytes (xdrs, (caddr_t) &mylong,
			    BYTES_PER_XDR_UNIT))
	return FALSE;
      *ip = ntohl (mylong);
    }
  return TRUE;
}

static bool_t
xdrrec_putint32 (XDR *xdrs, const int32_t *ip)
{
  RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
  int32_t *dest_ip = (int32_t *) rstrm->out_finger;

  if ((rstrm->out_finger += BYTES_PER_XDR_UNIT) > rstrm->out_boundry)
    {
      /*
       * this case should almost never happen so the code is
       * inefficient
       */
      rstrm->out_finger -= BYTES_PER_XDR_UNIT;
      rstrm->frag_sent = TRUE;
      if (!flush_out (rstrm, FALSE))
	return FALSE;
      dest_ip = (int32_t *) rstrm->out_finger;
      rstrm->out_finger += BYTES_PER_XDR_UNIT;
    }
  *dest_ip = htonl (*ip);
  return TRUE;
}

/*
 * Exported routines to manage xdr records
 */

/*
 * Before reading (deserializing from the stream, one should always call
 * this procedure to guarantee proper record alignment.
 */
bool_t
xdrrec_skiprecord (XDR *xdrs)
{
  RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;

  while (rstrm->fbtbc > 0 || (!rstrm->last_frag))
    {
      if (!skip_input_bytes (rstrm, rstrm->fbtbc))
	return FALSE;
      rstrm->fbtbc = 0;
      if ((!rstrm->last_frag) && (!set_input_fragment (rstrm)))
	return FALSE;
    }
  rstrm->last_frag = FALSE;
  return TRUE;
}

/*
 * Lookahead function.
 * Returns TRUE iff there is no more input in the buffer
 * after consuming the rest of the current record.
 */
bool_t
xdrrec_eof (XDR *xdrs)
{
  RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;

  while (rstrm->fbtbc > 0 || (!rstrm->last_frag))
    {
      if (!skip_input_bytes (rstrm, rstrm->fbtbc))
	return TRUE;
      rstrm->fbtbc = 0;
      if ((!rstrm->last_frag) && (!set_input_fragment (rstrm)))
	return TRUE;
    }
  if (rstrm->in_finger == rstrm->in_boundry)
    return TRUE;
  return FALSE;
}

/*
 * The client must tell the package when an end-of-record has occurred.
 * The second parameter tells whether the record should be flushed to the
 * (output) tcp stream.  (This lets the package support batched or
 * pipelined procedure calls.)  TRUE => immediate flush to tcp connection.
 */
bool_t
xdrrec_endofrecord (XDR *xdrs, bool_t sendnow)
{
  RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
  u_long len;		/* fragment length */

  if (sendnow || rstrm->frag_sent
      || rstrm->out_finger + BYTES_PER_XDR_UNIT >= rstrm->out_boundry)
    {
      rstrm->frag_sent = FALSE;
      return flush_out (rstrm, TRUE);
    }
  len = (rstrm->out_finger - (char *) rstrm->frag_header
	 - BYTES_PER_XDR_UNIT);
  *rstrm->frag_header = htonl ((u_long) len | LAST_FRAG);
  rstrm->frag_header = (u_int32_t *) rstrm->out_finger;
  rstrm->out_finger += BYTES_PER_XDR_UNIT;
  return TRUE;
}


/*
 * Internal useful routines
 */
static bool_t
internal_function
flush_out (RECSTREAM *rstrm, bool_t eor)
{
  u_long eormask = (eor == TRUE) ? LAST_FRAG : 0;
  u_long len = (rstrm->out_finger - (char *) rstrm->frag_header
		- BYTES_PER_XDR_UNIT);

  *rstrm->frag_header = htonl (len | eormask);
  len = rstrm->out_finger - rstrm->out_base;
  if ((*(rstrm->writeit)) (rstrm->tcp_handle, rstrm->out_base, (int) len)
      != (int) len)
    return FALSE;
  rstrm->frag_header = (u_int32_t *) rstrm->out_base;
  rstrm->out_finger = (caddr_t) rstrm->out_base + BYTES_PER_XDR_UNIT;
  return TRUE;
}

static bool_t	/* knows nothing about records!  Only about input buffers */
fill_input_buf (RECSTREAM *rstrm)
{
  caddr_t where;
  size_t i;
  int len;

  where = rstrm->in_base;
  i = (size_t) rstrm->in_boundry % BYTES_PER_XDR_UNIT;
  where += i;
  len = rstrm->in_size - i;
  if ((len = (*(rstrm->readit)) (rstrm->tcp_handle, where, len)) == -1)
    return FALSE;
  rstrm->in_finger = where;
  where += len;
  rstrm->in_boundry = where;
  return TRUE;
}

static bool_t	/* knows nothing about records!  Only about input buffers */
internal_function
get_input_bytes (RECSTREAM *rstrm, caddr_t addr, int len)
{
  int current;

  while (len > 0)
    {
      current = rstrm->in_boundry - rstrm->in_finger;
      if (current == 0)
	{
	  if (!fill_input_buf (rstrm))
	    return FALSE;
	  continue;
	}
      current = (len < current) ? len : current;
      memcpy (addr, rstrm->in_finger, current);
      rstrm->in_finger += current;
      addr += current;
      len -= current;
    }
  return TRUE;
}

static bool_t /* next two bytes of the input stream are treated as a header */
internal_function
set_input_fragment (RECSTREAM *rstrm)
{
  uint32_t header;

  if (! get_input_bytes (rstrm, (caddr_t)&header, BYTES_PER_XDR_UNIT))
    return FALSE;
  header = ntohl (header);
  rstrm->last_frag = ((header & LAST_FRAG) == 0) ? FALSE : TRUE;
  /*
   * Sanity check. Try not to accept wildly incorrect fragment
   * sizes. Unfortunately, only a size of zero can be identified as
   * 'wildely incorrect', and this only, if it is not the last
   * fragment of a message. Ridiculously large fragment sizes may look
   * wrong, but we don't have any way to be certain that they aren't
   * what the client actually intended to send us. Many existing RPC
   * implementations may sent a fragment of size zero as the last
   * fragment of a message.
   */
  if (header == 0)
    return FALSE;
  rstrm->fbtbc = header & ~LAST_FRAG;
  return TRUE;
}

static bool_t	/* consumes input bytes; knows nothing about records! */
internal_function
skip_input_bytes (RECSTREAM *rstrm, long cnt)
{
  int current;

  while (cnt > 0)
    {
      current = rstrm->in_boundry - rstrm->in_finger;
      if (current == 0)
	{
	  if (!fill_input_buf (rstrm))
	    return FALSE;
	  continue;
	}
      current = (cnt < current) ? cnt : current;
      rstrm->in_finger += current;
      cnt -= current;
    }
  return TRUE;
}

static u_int
internal_function
fix_buf_size (u_int s)
{
  if (s < 100)
    s = 4000;
  return RNDUP (s);
}