/* $Id: mbf.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 _MBF_H_
#define _MBF_H_

struct mbf {
	struct mbuf *mbf_m0;	/* beginning of mbuf */
	struct mbuf *mbf_cur;	/* current pointed mbuf */
	unsigned int mbf_flags;
#define	MBFFLAGS_RDONLY		0x00000001
#define	MBFFLAGS_WRONLY		0x00000002
#define	MBFFLAGS_RDWR		(MBFFLAGS_RDONLY|MBFFLAGS_WRONLY)
#define	MBFFLAGS_MODEMASK	MBFFLAGS_RDWR
	int mbf_size;		/* total amount of mbuf chain. 0 is unknown */
	int mbf_cur_base;	/* offset of mbf_cur in mbuf chain */
	int mbf_cur_offset;	/* offset of pointer in mbf_cur */
};

void mbf_open(struct mbf *, struct mbuf *, unsigned int);
static inline void mbf_close(struct mbf *);
static inline int mbf_length(struct mbf *);
static inline int mbf_tell(struct mbf *);
static inline int mbf_eof(struct mbf *mbf);
int mbf_seek(struct mbf *, int, int);
#define	mbf_rewind(mbf)	mbf_seek(mbf, 0, 0)

int mbf_read_1(struct mbf *);
int mbf_read_2(struct mbf *);
uint32_t mbf_read_4(struct mbf *);
int mbf_read(struct mbf *, void *, int);
void *mbf_getbuf(struct mbf *, void *, int);


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

static inline int
mbf_length(struct mbf *mbf)
{
	if (mbf->mbf_size == 0)
		mbf->mbf_size = m_length(mbf->mbf_m0);
	return mbf->mbf_size;
}

static inline int
mbf_tell(struct mbf *mbf)
{
	return mbf->mbf_cur_base + mbf->mbf_cur_offset;
}

static inline int
mbf_eof(struct mbf *mbf)
{
	return (mbf->mbf_cur->m_next == NULL) &&
	    (mbf->mbf_cur->m_len == mbf->mbf_cur_offset);

}

/* DEBUG */
void mbf_dump(struct mbf *);

#endif /* _MBF_H_ */