1/* 2 * Copyright (c) 2003-2003 3 * Fraunhofer Institute for Open Communication Systems (FhG Fokus). 4 * All rights reserved. 5 * 6 * Author: Hartmut Brandt <harti@freebsd.org> 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * $Begemot: libunimsg/netnatm/misc/unimsg_common.c,v 1.3 2004/07/08 08:22:03 brandt Exp $ 30 */ 31 32#include <netnatm/unimsg.h> 33 34/* 35 * Make sure there is enough space in front of the data for 36 * len bytes, and update the read pointer. 37 */ 38int 39uni_msg_prepend(struct uni_msg *msg, size_t len) 40{ 41 size_t need; 42 43 if (uni_msg_leading(msg) >= len) { 44 msg->b_rptr -= len; 45 return (0); 46 } 47 need = len - uni_msg_leading(msg); 48 if (uni_msg_ensure(msg, need)) 49 return (-1); 50 memcpy(msg->b_rptr + need, msg->b_rptr, uni_msg_len(msg)); 51 msg->b_rptr += need - len; 52 msg->b_wptr += need; 53 return (0); 54} 55