/* $Id: mbh.h,v 1.1 2008/05/06 20:04:41 ryo Exp $ */

/*
 * Copyright (c) 2008 SHIMIZU Ryo <ryo@nerv.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef _MBH_H_
#define _MBH_H_

#undef MBH_DEBUG


struct mbh {
	struct mbuf *mbh_m;	/* current pointed mbuf */
	int mbh_offset;		/* offset of pointer in mbuf */
};

static struct mbh *mbh_open(struct mbh *, struct mbuf *, unsigned int);
static inline void mbh_close(struct mbh *);
int mbh_forward(struct mbh *, int);
int mbh_read_1(struct mbh *);
int mbh_read_2(struct mbh *);
uint32_t mbh_read_4(struct mbh *);
int mbh_read(struct mbh *, void *, int);
void *mbh_getbuf(struct mbh *, void *, int);

static inline struct mbh *
mbh_open(struct mbh *mbh, struct mbuf *m, unsigned int offset)
{
	mbh->mbh_m = m_getptr(m, offset, &mbh->mbh_offset);
	if (mbh->mbh_m == NULL)
		return NULL;
	return mbh;
}

static inline void
mbh_close(struct mbh *mbh __unused)
{
	/* nothing to do */
	return;
}

#ifdef MBH_DEBUG
void mbh_dump(struct mbh *);
#else
#define mbh_dump(mbh)
#endif

#endif /* _MBH_H_ */