games/trek/dumpgame.c

   1 /*-
   2  * Copyright (c) 1980, 1993
   3  *      The Regents of the University of California.  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. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * @(#)dumpgame.c       8.1 (Berkeley) 5/31/93
  30  * $FreeBSD: src/games/trek/dumpgame.c,v 1.6 1999/11/30 03:49:46 billf Exp $
  31  * $DragonFly: src/games/trek/dumpgame.c,v 1.3 2006/09/07 21:19:44 pavalos Exp $
  32  */
  33
  34 #include <fcntl.h>
  35
  36 #include "trek.h"
  37
  38 /***  THIS CONSTANT MUST CHANGE AS THE DATA SPACES CHANGE ***/
  39 #define VERSION         2
  40
  41 struct dump {
  42         char    *area;
  43         int     count;
  44 };
  45
  46 static bool readdump(int);
  47
  48 struct dump Dump_template[] = {
  49         { (char *)&Ship,        sizeof (Ship)   },
  50         { (char *)&Now,         sizeof (Now)    },
  51         { (char *)&Param,       sizeof (Param)  },
  52         { (char *)&Etc,         sizeof (Etc)    },
  53         { (char *)&Game,        sizeof (Game)   },
  54         { (char *)Sect,         sizeof (Sect)   },
  55         { (char *)Quad,         sizeof (Quad)   },
  56         { (char *)&Move,        sizeof (Move)   },
  57         { (char *)Event,        sizeof (Event)  },
  58         { NULL,                 0               }
  59 };
  60
  61 /*
  62 **  DUMP GAME
  63 **
  64 **      This routine dumps the game onto the file "trek.dump".  The
  65 **      first two bytes of the file are a version number, which
  66 **      reflects whether this image may be used.  Obviously, it must
  67 **      change as the size, content, or order of the data structures
  68 **      output change.
  69 */
  70
  71 void
  72 dumpgame(int v __unused)
  73 {
  74         int             version;
  75         int             fd;
  76         struct dump     *d;
  77         int             i;
  78
  79         if ((fd = creat("trek.dump", 0644)) < 0) {
  80                 printf("cannot dump\n");
  81                 return;
  82         }
  83         version = VERSION;
  84         write(fd, &version, sizeof version);
  85
  86         /* output the main data areas */
  87         for (d = Dump_template; d->area; d++) {
  88                 write(fd, &d->area, sizeof d->area);
  89                 i = d->count;
  90                 write(fd, d->area, i);
  91         }
  92
  93         close(fd);
  94 }
  95
  96
  97 /*
  98 **  RESTORE GAME
  99 **
 100 **      The game is restored from the file "trek.dump".  In order for
 101 **      this to succeed, the file must exist and be readable, must
 102 **      have the correct version number, and must have all the appro-
 103 **      priate data areas.
 104 **
 105 **      Return value is zero for success, one for failure.
 106 */
 107
 108 bool
 109 restartgame(void)
 110 {
 111         int     fd;
 112         int             version;
 113
 114         if ((fd = open("trek.dump", O_RDONLY)) < 0 ||
 115             read(fd, &version, sizeof version) != sizeof version ||
 116             version != VERSION ||
 117             readdump(fd)) {
 118                 printf("cannot restart\n");
 119                 close(fd);
 120                 return (1);
 121         }
 122
 123         close(fd);
 124         return (0);
 125 }
 126
 127
 128 /*
 129 **  READ DUMP
 130 **
 131 **      This is the business end of restartgame().  It reads in the
 132 **      areas.
 133 **
 134 **      Returns zero for success, one for failure.
 135 */
 136
 137 static bool
 138 readdump(int fd1)
 139 {
 140         int             fd;
 141         struct dump     *d;
 142         int             i;
 143         long                    junk;
 144
 145         fd = fd1;
 146
 147         for (d = Dump_template; d->area; d++) {
 148                 if (read(fd, &junk, sizeof junk) != (sizeof junk))
 149                         return (1);
 150                 if ((char *)junk != d->area)
 151                         return (1);
 152                 i = d->count;
 153                 if (read(fd, d->area, i) != i)
 154                         return (1);
 155         }
 156
 157         /* make quite certain we are at EOF */
 158         return (read(fd, &junk, 1));
 159 }