1 /* 2 * Copyright (c) 1980 Regents of the University of California. 3 * All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 */ 7 8 #ifndef lint 9 static char sccsid[] = "@(#)dumpgame.c 4.6 (Berkeley) 06/01/90"; 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 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 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 */ 111 112 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