55 lines
2.0 KiB
C
55 lines
2.0 KiB
C
/*
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* Copyright (c) 2003-2003
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* Fraunhofer Institute for Open Communication Systems (FhG Fokus).
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* All rights reserved.
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*
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* Author: Hartmut Brandt <harti@freebsd.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Begemot: libunimsg/netnatm/misc/unimsg_common.c,v 1.3 2004/07/08 08:22:03 brandt Exp $
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*/
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#include <netnatm/unimsg.h>
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/*
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* Make sure there is enough space in front of the data for
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* len bytes, and update the read pointer.
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*/
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int
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uni_msg_prepend(struct uni_msg *msg, size_t len)
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{
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size_t need;
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if (uni_msg_leading(msg) >= len) {
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msg->b_rptr -= len;
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return (0);
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}
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need = len - uni_msg_leading(msg);
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if (uni_msg_ensure(msg, need))
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return (-1);
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memcpy(msg->b_rptr + need, msg->b_rptr, uni_msg_len(msg));
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msg->b_rptr += need - len;
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msg->b_wptr += need;
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return (0);
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}
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