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dumpgame.c revision 1.7 
      1 /*	$NetBSD: dumpgame.c,v 1.7 1999/09/08 21:45:32 jsm Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1980, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 #ifndef lint
     38 #if 0
     39 static char sccsid[] = "@(#)dumpgame.c	8.1 (Berkeley) 5/31/93";
     40 #else
     41 __RCSID("$NetBSD: dumpgame.c,v 1.7 1999/09/08 21:45:32 jsm Exp $");
     42 #endif
     43 #endif /* not lint */
     44 
     45 #include <stdio.h>
     46 #include <err.h>
     47 #include <unistd.h>
     48 #include <fcntl.h>
     49 #include "trek.h"
     50 
     51 /***  THIS CONSTANT MUST CHANGE AS THE DATA SPACES CHANGE ***/
     52 # define	VERSION		2
     53 
     54 struct dump
     55 {
     56 	char	*area;
     57 	int	count;
     58 };
     59 
     60 static int readdump __P((int));
     61 
     62 
     63 struct dump	Dump_template[] =
     64 {
     65 	{ (char *)&Ship,	sizeof (Ship) },
     66 	{ (char *)&Now,		sizeof (Now) },
     67 	{ (char *)&Param,	sizeof (Param) },
     68 	{ (char *)&Etc,		sizeof (Etc) },
     69 	{ (char *)&Game,	sizeof (Game) },
     70 	{ (char *)Sect,		sizeof (Sect) },
     71 	{ (char *)Quad,		sizeof (Quad) },
     72 	{ (char *)&Move,	sizeof (Move) },
     73 	{ (char *)Event,	sizeof (Event) },
     74 	{ NULL,			0 }
     75 };
     76 
     77 /*
     78 **  DUMP GAME
     79 **
     80 **	This routine dumps the game onto the file "trek.dump".  The
     81 **	first two bytes of the file are a version number, which
     82 **	reflects whether this image may be used.  Obviously, it must
     83 **	change as the size, content, or order of the data structures
     84 **	output change.
     85 */
     86 
     87 /*ARGSUSED*/
     88 void
     89 dumpgame(v)
     90 	int v __attribute__((__unused__));
     91 {
     92 	int		version;
     93 	int		fd;
     94 	struct dump	*d;
     95 	int		i;
     96 
     97 	if ((fd = creat("trek.dump", 0644)) < 0) {
     98 		warn("cannot open `trek.dump'");
     99 		return;
    100 	}
    101 	version = VERSION;
    102 	write(fd, &version, sizeof version);
    103 
    104 	/* output the main data areas */
    105 	for (d = Dump_template; d->area; d++)
    106 	{
    107 		write(fd, &d->area, sizeof d->area);
    108 		i = d->count;
    109 		write(fd, d->area, i);
    110 	}
    111 
    112 	close(fd);
    113 }
    114 
    115 
    116 /*
    117 **  RESTORE GAME
    118 **
    119 **	The game is restored from the file "trek.dump".  In order for
    120 **	this to succeed, the file must exist and be readable, must
    121 **	have the correct version number, and must have all the appro-
    122 **	priate data areas.
    123 **
    124 **	Return value is zero for success, one for failure.
    125 */
    126 
    127 int
    128 restartgame()
    129 {
    130 	int	fd;
    131 	int		version;
    132 
    133 	if ((fd = open("trek.dump", O_RDONLY)) < 0 ||
    134 	    read(fd, &version, sizeof version) != sizeof version ||
    135 	    version != VERSION ||
    136 	    readdump(fd))
    137 	{
    138 		printf("cannot restart\n");
    139 		close(fd);
    140 		return (1);
    141 	}
    142 
    143 	close(fd);
    144 	return (0);
    145 }
    146 
    147 
    148 /*
    149 **  READ DUMP
    150 **
    151 **	This is the business end of restartgame().  It reads in the
    152 **	areas.
    153 **
    154 **	Returns zero for success, one for failure.
    155 */
    156 
    157 static int
    158 readdump(fd1)
    159 int	fd1;
    160 {
    161 	int		fd;
    162 	struct dump	*d;
    163 	int		i;
    164 	long			junk;
    165 
    166 	fd = fd1;
    167 
    168 	for (d = Dump_template; d->area; d++)
    169 	{
    170 		if (read(fd, &junk, sizeof junk) != (sizeof junk))
    171 			return (1);
    172 		if ((char *)junk != d->area)
    173 			return (1);
    174 		i = d->count;
    175 		if (read(fd, d->area, i) != i)
    176 			return (1);
    177 	}
    178 
    179 	/* make quite certain we are at EOF */
    180 	return (read(fd, &junk, 1));
    181 }
    182