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dumpgame.c revision 1.9 
      1 /*	$NetBSD: dumpgame.c,v 1.9 2004/01/27 20:30:31 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. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #ifndef lint
     34 #if 0
     35 static char sccsid[] = "@(#)dumpgame.c	8.1 (Berkeley) 5/31/93";
     36 #else
     37 __RCSID("$NetBSD: dumpgame.c,v 1.9 2004/01/27 20:30:31 jsm Exp $");
     38 #endif
     39 #endif /* not lint */
     40 
     41 #include <stdio.h>
     42 #include <err.h>
     43 #include <unistd.h>
     44 #include <fcntl.h>
     45 #include "trek.h"
     46 
     47 /***  THIS CONSTANT MUST CHANGE AS THE DATA SPACES CHANGE ***/
     48 # define	VERSION		2
     49 
     50 struct dump
     51 {
     52 	char	*area;
     53 	int	count;
     54 };
     55 
     56 static int readdump(int);
     57 
     58 
     59 struct dump	Dump_template[] =
     60 {
     61 	{ (char *)&Ship,	sizeof (Ship) },
     62 	{ (char *)&Now,		sizeof (Now) },
     63 	{ (char *)&Param,	sizeof (Param) },
     64 	{ (char *)&Etc,		sizeof (Etc) },
     65 	{ (char *)&Game,	sizeof (Game) },
     66 	{ (char *)Sect,		sizeof (Sect) },
     67 	{ (char *)Quad,		sizeof (Quad) },
     68 	{ (char *)&Move,	sizeof (Move) },
     69 	{ (char *)Event,	sizeof (Event) },
     70 	{ NULL,			0 }
     71 };
     72 
     73 /*
     74 **  DUMP GAME
     75 **
     76 **	This routine dumps the game onto the file "trek.dump".  The
     77 **	first two bytes of the file are a version number, which
     78 **	reflects whether this image may be used.  Obviously, it must
     79 **	change as the size, content, or order of the data structures
     80 **	output change.
     81 */
     82 
     83 /*ARGSUSED*/
     84 void
     85 dumpgame(v)
     86 	int v __attribute__((__unused__));
     87 {
     88 	int		version;
     89 	int		fd;
     90 	struct dump	*d;
     91 	int		i;
     92 
     93 	if ((fd = creat("trek.dump", 0644)) < 0) {
     94 		warn("cannot open `trek.dump'");
     95 		return;
     96 	}
     97 	version = VERSION;
     98 	write(fd, &version, sizeof version);
     99 
    100 	/* output the main data areas */
    101 	for (d = Dump_template; d->area; d++)
    102 	{
    103 		write(fd, &d->area, sizeof d->area);
    104 		i = d->count;
    105 		write(fd, d->area, i);
    106 	}
    107 
    108 	close(fd);
    109 }
    110 
    111 
    112 /*
    113 **  RESTORE GAME
    114 **
    115 **	The game is restored from the file "trek.dump".  In order for
    116 **	this to succeed, the file must exist and be readable, must
    117 **	have the correct version number, and must have all the appro-
    118 **	priate data areas.
    119 **
    120 **	Return value is zero for success, one for failure.
    121 */
    122 
    123 int
    124 restartgame()
    125 {
    126 	int	fd;
    127 	int		version;
    128 
    129 	if ((fd = open("trek.dump", O_RDONLY)) < 0 ||
    130 	    read(fd, &version, sizeof version) != sizeof version ||
    131 	    version != VERSION ||
    132 	    readdump(fd))
    133 	{
    134 		printf("cannot restart\n");
    135 		close(fd);
    136 		return (1);
    137 	}
    138 
    139 	close(fd);
    140 	return (0);
    141 }
    142 
    143 
    144 /*
    145 **  READ DUMP
    146 **
    147 **	This is the business end of restartgame().  It reads in the
    148 **	areas.
    149 **
    150 **	Returns zero for success, one for failure.
    151 */
    152 
    153 static int
    154 readdump(fd1)
    155 int	fd1;
    156 {
    157 	int		fd;
    158 	struct dump	*d;
    159 	int		i;
    160 	long			junk;
    161 
    162 	fd = fd1;
    163 
    164 	for (d = Dump_template; d->area; d++)
    165 	{
    166 		if (read(fd, &junk, sizeof junk) != (sizeof junk))
    167 			return (1);
    168 		if ((char *)junk != d->area)
    169 			return (1);
    170 		i = d->count;
    171 		if (read(fd, d->area, i) != i)
    172 			return (1);
    173 	}
    174 
    175 	/* make quite certain we are at EOF */
    176 	return (read(fd, &junk, 1));
    177 }
    178