1121326Sharti/* 2121326Sharti * Copyright (c) 2003-2003 3121326Sharti * Fraunhofer Institute for Open Communication Systems (FhG Fokus). 4121326Sharti * All rights reserved. 5121326Sharti * 6131826Sharti * Author: Hartmut Brandt <harti@freebsd.org> 7131826Sharti * 8121326Sharti * Redistribution and use in source and binary forms, with or without 9121326Sharti * modification, are permitted provided that the following conditions 10121326Sharti * are met: 11121326Sharti * 1. Redistributions of source code must retain the above copyright 12121326Sharti * notice, this list of conditions and the following disclaimer. 13121326Sharti * 2. Redistributions in binary form must reproduce the above copyright 14121326Sharti * notice, this list of conditions and the following disclaimer in the 15121326Sharti * documentation and/or other materials provided with the distribution. 16121326Sharti * 17121326Sharti * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18121326Sharti * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19121326Sharti * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20121326Sharti * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21121326Sharti * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22121326Sharti * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23121326Sharti * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24121326Sharti * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25121326Sharti * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26121326Sharti * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27121326Sharti * SUCH DAMAGE. 28121326Sharti * 29131826Sharti * $Begemot: libunimsg/netnatm/misc/unimsg_common.c,v 1.3 2004/07/08 08:22:03 brandt Exp $ 30121326Sharti */ 31121326Sharti 32121326Sharti#include <netnatm/unimsg.h> 33121326Sharti 34121326Sharti/* 35121326Sharti * Make sure there is enough space in front of the data for 36121326Sharti * len bytes, and update the read pointer. 37121326Sharti */ 38121326Shartiint 39121326Shartiuni_msg_prepend(struct uni_msg *msg, size_t len) 40121326Sharti{ 41121326Sharti size_t need; 42121326Sharti 43121326Sharti if (uni_msg_leading(msg) >= len) { 44121326Sharti msg->b_rptr -= len; 45121326Sharti return (0); 46121326Sharti } 47121326Sharti need = len - uni_msg_leading(msg); 48121326Sharti if (uni_msg_ensure(msg, need)) 49121326Sharti return (-1); 50121326Sharti memcpy(msg->b_rptr + need, msg->b_rptr, uni_msg_len(msg)); 51121326Sharti msg->b_rptr += need - len; 52121326Sharti msg->b_wptr += need; 53121326Sharti return (0); 54121326Sharti} 55