/*
 * Copyright (c) 1980 Regents of the University of California.
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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 lint
static char sccsid[] = "@(#)dumpgame.c	4.6 (Berkeley) 6/1/90";
#endif /* not lint */

# include	"trek.h"

/***  THIS CONSTANT MUST CHANGE AS THE DATA SPACES CHANGE ***/
# define	VERSION		2

struct dump
{
	char	*area;
	int	count;
};


struct dump	Dump_template[] =
{
	(char *)&Ship,		sizeof (Ship),
	(char *)&Now,		sizeof (Now),
	(char *)&Param,		sizeof (Param),
	(char *)&Etc,		sizeof (Etc),
	(char *)&Game,		sizeof (Game),
	(char *)Sect,		sizeof (Sect),
	(char *)Quad,		sizeof (Quad),
	(char *)&Move,		sizeof (Move),
	(char *)Event,		sizeof (Event),
	0
};

/*
**  DUMP GAME
**
**	This routine dumps the game onto the file "trek.dump".  The
**	first two bytes of the file are a version number, which
**	reflects whether this image may be used.  Obviously, it must
**	change as the size, content, or order of the data structures
**	output change.
*/

void dumpgame(void)
{
	int			version;
	register int		fd;
	register struct dump	*d;
	register int		i;

	if ((fd = creat("trek.dump", 0644)) < 0) {
		printf("cannot dump\n");
		return;
	}
	version = VERSION;
	write(fd, &version, sizeof version);

	/* output the main data areas */
	for (d = Dump_template; d->area; d++)
	{
		write(fd, &d->area, sizeof d->area);
		i = d->count;
		write(fd, d->area, i);
	}

	close(fd);
}


/*
**  RESTORE GAME
**
**	The game is restored from the file "trek.dump".  In order for
**	this to succeed, the file must exist and be readable, must
**	have the correct version number, and must have all the appro-
**	priate data areas.
**
**	Return value is zero for success, one for failure.
*/

int restartgame(void)
{
	register int	fd;
	int		version;

	if ((fd = open("trek.dump", 0)) < 0 ||
	    read(fd, &version, sizeof version) != sizeof version ||
	    version != VERSION ||
	    readdump(fd))
	{
		printf("cannot restart\n");
		close(fd);
		return (1);
	}

	close(fd);
	return (0);
}


/*
**  READ DUMP
**
**	This is the business end of restartgame().  It reads in the
**	areas.
**
**	Returns zero for success, one for failure.
*/

int readdump(int fd1)
{
	register int		fd;
	register struct dump	*d;
	register int		i;
	int			junk;

	fd = fd1;

	for (d = Dump_template; d->area; d++)
	{
		if (read(fd, &junk, sizeof junk) != (sizeof junk))
			return (1);
		if ((char *)junk != d->area)
			return (1);
		i = d->count;
		if (read(fd, d->area, i) != i)
			return (1);
	}

	/* make quite certain we are at EOF */
	return (read(fd, &junk, 1));
}
