4.3BSD-Reno/src/games/trek/dumpgame.c

/*
 * Copyright (c) 1980 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted provided
 * that: (1) source distributions retain this entire copyright notice and
 * comment, and (2) distributions including binaries display the following
 * acknowledgement:  ``This product includes software developed by the
 * University of California, Berkeley and its contributors'' in the
 * documentation or other materials provided with the distribution and in
 * all advertising materials mentioning features or use of this software.
 * 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#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.
*/

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

	if ((fd = creat("trek.dump", 0644)) < 0)
		return (printf("cannot dump\n"));
	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.
*/

restartgame()
{
	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.
*/

readdump(fd1)
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));
}