1 /*
2 * Copyright (c) 1980, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * %sccs.include.redist.c%
6 */
7
8 #ifndef lint
9 static char sccsid[] = "@(#)dumpgame.c 8.1 (Berkeley) 05/31/93";
10 #endif /* not lint */
11
12 # include "trek.h"
13
14 /*** THIS CONSTANT MUST CHANGE AS THE DATA SPACES CHANGE ***/
15 # define VERSION 2
16
17 struct dump
18 {
19 char *area;
20 int count;
21 };
22
23
24 struct dump Dump_template[] =
25 {
26 (char *)&Ship, sizeof (Ship),
27 (char *)&Now, sizeof (Now),
28 (char *)&Param, sizeof (Param),
29 (char *)&Etc, sizeof (Etc),
30 (char *)&Game, sizeof (Game),
31 (char *)Sect, sizeof (Sect),
32 (char *)Quad, sizeof (Quad),
33 (char *)&Move, sizeof (Move),
34 (char *)Event, sizeof (Event),
35 0
36 };
37
38 /*
39 ** DUMP GAME
40 **
41 ** This routine dumps the game onto the file "trek.dump". The
42 ** first two bytes of the file are a version number, which
43 ** reflects whether this image may be used. Obviously, it must
44 ** change as the size, content, or order of the data structures
45 ** output change.
46 */
47
dumpgame()48 dumpgame()
49 {
50 int version;
51 register int fd;
52 register struct dump *d;
53 register int i;
54
55 if ((fd = creat("trek.dump", 0644)) < 0)
56 return (printf("cannot dump\n"));
57 version = VERSION;
58 write(fd, &version, sizeof version);
59
60 /* output the main data areas */
61 for (d = Dump_template; d->area; d++)
62 {
63 write(fd, &d->area, sizeof d->area);
64 i = d->count;
65 write(fd, d->area, i);
66 }
67
68 close(fd);
69 }
70
71
72 /*
73 ** RESTORE GAME
74 **
75 ** The game is restored from the file "trek.dump". In order for
76 ** this to succeed, the file must exist and be readable, must
77 ** have the correct version number, and must have all the appro-
78 ** priate data areas.
79 **
80 ** Return value is zero for success, one for failure.
81 */
82
restartgame()83 restartgame()
84 {
85 register int fd;
86 int version;
87
88 if ((fd = open("trek.dump", 0)) < 0 ||
89 read(fd, &version, sizeof version) != sizeof version ||
90 version != VERSION ||
91 readdump(fd))
92 {
93 printf("cannot restart\n");
94 close(fd);
95 return (1);
96 }
97
98 close(fd);
99 return (0);
100 }
101
102
103 /*
104 ** READ DUMP
105 **
106 ** This is the business end of restartgame(). It reads in the
107 ** areas.
108 **
109 ** Returns zero for success, one for failure.
110 */
111
readdump(fd1)112 readdump(fd1)
113 int fd1;
114 {
115 register int fd;
116 register struct dump *d;
117 register int i;
118 int junk;
119
120 fd = fd1;
121
122 for (d = Dump_template; d->area; d++)
123 {
124 if (read(fd, &junk, sizeof junk) != (sizeof junk))
125 return (1);
126 if ((char *)junk != d->area)
127 return (1);
128 i = d->count;
129 if (read(fd, d->area, i) != i)
130 return (1);
131 }
132
133 /* make quite certain we are at EOF */
134 return (read(fd, &junk, 1));
135 }
136