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dumpgame.c revision 1.2 
      1 /*
      2  * Copyright (c) 1980 Regents of the University of California.
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  * 3. All advertising materials mentioning features or use of this software
     14  *    must display the following acknowledgement:
     15  *	This product includes software developed by the University of
     16  *	California, Berkeley and its contributors.
     17  * 4. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  */
     33 
     34 #ifndef lint
     35 /*static char sccsid[] = "from: @(#)dumpgame.c	4.6 (Berkeley) 6/1/90";*/
     36 static char rcsid[] = "$Id: dumpgame.c,v 1.2 1993/08/01 18:50:39 mycroft Exp $";
     37 #endif /* not lint */
     38 
     39 # include	"trek.h"
     40 
     41 /***  THIS CONSTANT MUST CHANGE AS THE DATA SPACES CHANGE ***/
     42 # define	VERSION		2
     43 
     44 struct dump
     45 {
     46 	char	*area;
     47 	int	count;
     48 };
     49 
     50 
     51 struct dump	Dump_template[] =
     52 {
     53 	(char *)&Ship,		sizeof (Ship),
     54 	(char *)&Now,		sizeof (Now),
     55 	(char *)&Param,		sizeof (Param),
     56 	(char *)&Etc,		sizeof (Etc),
     57 	(char *)&Game,		sizeof (Game),
     58 	(char *)Sect,		sizeof (Sect),
     59 	(char *)Quad,		sizeof (Quad),
     60 	(char *)&Move,		sizeof (Move),
     61 	(char *)Event,		sizeof (Event),
     62 	0
     63 };
     64 
     65 /*
     66 **  DUMP GAME
     67 **
     68 **	This routine dumps the game onto the file "trek.dump".  The
     69 **	first two bytes of the file are a version number, which
     70 **	reflects whether this image may be used.  Obviously, it must
     71 **	change as the size, content, or order of the data structures
     72 **	output change.
     73 */
     74 
     75 dumpgame()
     76 {
     77 	int			version;
     78 	register int		fd;
     79 	register struct dump	*d;
     80 	register int		i;
     81 
     82 	if ((fd = creat("trek.dump", 0644)) < 0)
     83 		return (printf("cannot dump\n"));
     84 	version = VERSION;
     85 	write(fd, &version, sizeof version);
     86 
     87 	/* output the main data areas */
     88 	for (d = Dump_template; d->area; d++)
     89 	{
     90 		write(fd, &d->area, sizeof d->area);
     91 		i = d->count;
     92 		write(fd, d->area, i);
     93 	}
     94 
     95 	close(fd);
     96 }
     97 
     98 
     99 /*
    100 **  RESTORE GAME
    101 **
    102 **	The game is restored from the file "trek.dump".  In order for
    103 **	this to succeed, the file must exist and be readable, must
    104 **	have the correct version number, and must have all the appro-
    105 **	priate data areas.
    106 **
    107 **	Return value is zero for success, one for failure.
    108 */
    109 
    110 restartgame()
    111 {
    112 	register int	fd;
    113 	int		version;
    114 
    115 	if ((fd = open("trek.dump", 0)) < 0 ||
    116 	    read(fd, &version, sizeof version) != sizeof version ||
    117 	    version != VERSION ||
    118 	    readdump(fd))
    119 	{
    120 		printf("cannot restart\n");
    121 		close(fd);
    122 		return (1);
    123 	}
    124 
    125 	close(fd);
    126 	return (0);
    127 }
    128 
    129 
    130 /*
    131 **  READ DUMP
    132 **
    133 **	This is the business end of restartgame().  It reads in the
    134 **	areas.
    135 **
    136 **	Returns zero for success, one for failure.
    137 */
    138 
    139 readdump(fd1)
    140 int	fd1;
    141 {
    142 	register int		fd;
    143 	register struct dump	*d;
    144 	register int		i;
    145 	int			junk;
    146 
    147 	fd = fd1;
    148 
    149 	for (d = Dump_template; d->area; d++)
    150 	{
    151 		if (read(fd, &junk, sizeof junk) != (sizeof junk))
    152 			return (1);
    153 		if ((char *)junk != d->area)
    154 			return (1);
    155 		i = d->count;
    156 		if (read(fd, d->area, i) != i)
    157 			return (1);
    158 	}
    159 
    160 	/* make quite certain we are at EOF */
    161 	return (read(fd, &junk, 1));
    162 }
    163