unimsg_common.c revision 121326
1139826Simp/* 253541Sshin * Copyright (c) 2003-2003 353541Sshin * Fraunhofer Institute for Open Communication Systems (FhG Fokus). 453541Sshin * All rights reserved. 553541Sshin * 653541Sshin * Redistribution and use in source and binary forms, with or without 753541Sshin * modification, are permitted provided that the following conditions 853541Sshin * are met: 953541Sshin * 1. Redistributions of source code must retain the above copyright 1053541Sshin * notice, this list of conditions and the following disclaimer. 1153541Sshin * 2. Redistributions in binary form must reproduce the above copyright 1253541Sshin * notice, this list of conditions and the following disclaimer in the 1353541Sshin * documentation and/or other materials provided with the distribution. 1453541Sshin * 1553541Sshin * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 1653541Sshin * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 1753541Sshin * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 1853541Sshin * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 1953541Sshin * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 2053541Sshin * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2153541Sshin * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2253541Sshin * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2353541Sshin * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 2453541Sshin * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 2553541Sshin * SUCH DAMAGE. 2653541Sshin * 2753541Sshin * Author: Hartmut Brandt <harti@freebsd.org> 28174510Sobrien * 29174510Sobrien * $Begemot: libunimsg/atm/misc/unimsg_common.c,v 1.2 2003/09/19 12:05:45 hbb Exp $ 30174510Sobrien */ 3153541Sshin 3253541Sshin#include <netnatm/unimsg.h> 3353541Sshin 3462587Sitojun/* 3553541Sshin * Make sure there is enough space in front of the data for 3662587Sitojun * len bytes, and update the read pointer. 3762587Sitojun */ 3862587Sitojunint 3962587Sitojununi_msg_prepend(struct uni_msg *msg, size_t len) 4062587Sitojun{ 4153541Sshin size_t need; 4278064Sume 4353541Sshin if (uni_msg_leading(msg) >= len) { 4453541Sshin msg->b_rptr -= len; 4553541Sshin return (0); 4653541Sshin } 4753541Sshin need = len - uni_msg_leading(msg); 4853541Sshin if (uni_msg_ensure(msg, need)) 4953541Sshin return (-1); 5053541Sshin memcpy(msg->b_rptr + need, msg->b_rptr, uni_msg_len(msg)); 5153541Sshin msg->b_rptr += need - len; 5253541Sshin msg->b_wptr += need; 5362587Sitojun return (0); 54151539Ssuz} 55151539Ssuz