games/trek/dumpgame.c

   1 /*      @(#)dumpgame.c  8.1 (Berkeley) 5/31/93                          */
   2 /*      $NetBSD: dumpgame.c,v 1.15 2009/08/12 08:54:54 dholland Exp $   */
   3
   4 /*
   5  * Copyright (c) 1980, 1993
   6  *      The Regents of the University of California.  All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #include <stdio.h>
  34 #include <err.h>
  35 #include <unistd.h>
  36 #include <fcntl.h>
  37 #include "trek.h"
  38
  39 /***  THIS CONSTANT MUST CHANGE AS THE DATA SPACES CHANGE ***/
  40 #define VERSION         2
  41
  42 struct dump {
  43         char    *area;
  44         int     count;
  45 };
  46
  47 static int readdump(int);
  48
  49
  50 static struct dump Dump_template[] = {
  51         { (char *)&Ship,        sizeof (Ship) },
  52         { (char *)&Now,         sizeof (Now) },
  53         { (char *)&Param,       sizeof (Param) },
  54         { (char *)&Etc,         sizeof (Etc) },
  55         { (char *)&Game,        sizeof (Game) },
  56         { (char *)Sect,         sizeof (Sect) },
  57         { (char *)Quad,         sizeof (Quad) },
  58         { (char *)&Move,        sizeof (Move) },
  59         { (char *)Event,        sizeof (Event) },
  60         { NULL,                 0 }
  61 };
  62
  63 /*
  64 **  DUMP GAME
  65 **
  66 **      This routine dumps the game onto the file "trek.dump".  The
  67 **      first two bytes of the file are a version number, which
  68 **      reflects whether this image may be used.  Obviously, it must
  69 **      change as the size, content, or order of the data structures
  70 **      output change.
  71 */
  72
  73 /*ARGSUSED*/
  74 void
  75 dumpgame(int v __unused)
  76 {
  77         int             version;
  78         int             fd;
  79         struct dump     *d;
  80         int             i;
  81
  82         if ((fd = creat("trek.dump", 0644)) < 0) {
  83                 warn("cannot open `trek.dump'");
  84                 return;
  85         }
  86         version = VERSION;
  87         write(fd, &version, sizeof version);
  88
  89         /* output the main data areas */
  90         for (d = Dump_template; d->area; d++) {
  91                 write(fd, &d->area, sizeof d->area);
  92                 i = d->count;
  93                 write(fd, d->area, i);
  94         }
  95
  96         close(fd);
  97 }
  98
  99
 100 /*
 101 **  RESTORE GAME
 102 **
 103 **      The game is restored from the file "trek.dump".  In order for
 104 **      this to succeed, the file must exist and be readable, must
 105 **      have the correct version number, and must have all the appro-
 106 **      priate data areas.
 107 **
 108 **      Return value is zero for success, one for failure.
 109 */
 110
 111 int
 112 restartgame(void)
 113 {
 114         int     fd;
 115         int             version;
 116
 117         if ((fd = open("trek.dump", O_RDONLY)) < 0 ||
 118             read(fd, &version, sizeof version) != sizeof version ||
 119             version != VERSION ||
 120             readdump(fd)) {
 121                 printf("cannot restart\n");
 122                 if (fd >= 0)
 123                         close(fd);
 124                 return (1);
 125         }
 126
 127         close(fd);
 128         return (0);
 129 }
 130
 131
 132 /*
 133 **  READ DUMP
 134 **
 135 **      This is the business end of restartgame().  It reads in the
 136 **      areas.
 137 **
 138 **      Returns zero for success, one for failure.
 139 */
 140
 141 static int
 142 readdump(int fd1)
 143 {
 144         int             fd;
 145         struct dump     *d;
 146         int             i;
 147         long                    junk;
 148
 149         fd = fd1;
 150
 151         for (d = Dump_template; d->area; d++) {
 152                 if (read(fd, &junk, sizeof junk) != (sizeof junk))
 153                         return (1);
 154                 if ((char *)junk != d->area)
 155                         return (1);
 156                 i = d->count;
 157                 if (read(fd, d->area, i) != i)
 158                         return (1);
 159         }
 160
 161         /* make quite certain we are at EOF */
 162         return (read(fd, &junk, 1));
 163 }