xdr_rec.c

linux下用PCMCIA无线网卡虚拟无线AP的程序源码

	return (TRUE);
}

static u_int xdrrec_getpos(xdrs)
register XDR *xdrs;
{
	register RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
	register long pos;

	pos = lseek((int) rstrm->tcp_handle, (long) 0, 1);
	if (pos != -1)
		switch (xdrs->x_op) {

		case XDR_ENCODE:
			pos += rstrm->out_finger - rstrm->out_base;
			break;

		case XDR_DECODE:
			pos -= rstrm->in_boundry - rstrm->in_finger;
			break;

		default:
			pos = (u_int) - 1;
			break;
		}
	return ((u_int) pos);
}

static bool_t xdrrec_setpos(xdrs, pos)
register XDR *xdrs;
u_int pos;
{
	register 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:				/* silence the warnings */
		}
	return (FALSE);
}

static int32_t *xdrrec_inline(xdrs, len)
register XDR *xdrs;
int len;
{
	register 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:					/* silence the warnings */
	}
	return (buf);
}

static void xdrrec_destroy(xdrs)
register XDR *xdrs;
{
	register 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));
}


/*
 * 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(xdrs)
XDR *xdrs;
{
	register 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);
}

/*
 * Look ahead fuction.
 * Returns TRUE iff there is no more input in the buffer 
 * after consuming the rest of the current record.
 */
bool_t xdrrec_eof(xdrs)
XDR *xdrs;
{
	register 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 paraemters tells whether the record should be flushed to the
 * (output) tcp stream.  (This let's the package support batched or
 * pipelined procedure calls.)  TRUE => immmediate flush to tcp connection.
 */
bool_t xdrrec_endofrecord(xdrs, sendnow)
XDR *xdrs;
bool_t sendnow;
{
	register RECSTREAM *rstrm = (RECSTREAM *) (xdrs->x_private);
	register u_long len;		/* fragment length */

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


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

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

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

	where = rstrm->in_base;
	i = (u_int) 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 */
get_input_bytes(rstrm, addr, len)
register RECSTREAM *rstrm;
register caddr_t addr;
register int len;
{
	register int current;

	while (len > 0) {
		current = (int) rstrm->in_boundry - (int) rstrm->in_finger;
		if (current == 0) {
			if (!fill_input_buf(rstrm))
				return (FALSE);
			continue;
		}
		current = (len < current) ? len : current;
		bcopy(rstrm->in_finger, addr, 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 */
set_input_fragment(rstrm)
register RECSTREAM *rstrm;
{
	u_long header;

	if (!get_input_bytes(rstrm, (caddr_t) & header, sizeof(header)))
		return (FALSE);
	header = (long) ntohl(header);
	rstrm->last_frag = ((header & LAST_FRAG) == 0) ? FALSE : TRUE;
	rstrm->fbtbc = header & (~LAST_FRAG);
	return (TRUE);
}

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

	while (cnt > 0) {
		current = (int) rstrm->in_boundry - (int) 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 fix_buf_size(s)
register u_int s;
{

	if (s < 100)
		s = 4000;
	return (RNDUP(s));
}