# include "trek.h" /*** THIS CONSTANT MUST CHANGE AS THE DATA SPACES CHANGE ***/ # define VERSION 1 struct dump { char *area; int count; }; struct dump Dump_template[] { &Ship, sizeof Ship, &Now, sizeof Now, &Param, sizeof Param, &Etc, sizeof Etc, &Game, sizeof Game, &Sect, sizeof Sect, &Quad, sizeof Quad, &Move, sizeof Move, &Event, sizeof Event, 0 }; /* ** DUMP GAME ** ** This routine dumps the game onto the file "trek.dump". The ** first two bytes of the file are a version number, which ** reflects whether this image may be used. Obviously, it must ** change as the size, content, or order of the data structures ** output change. */ dumpgame() { int version; register int fd; register struct dump *d; register int i; if ((fd = creat("trek.dump", 0644)) < 0) return (printf("cannot dump\n")); version = VERSION; write(fd, &version, sizeof version); /* output the main data areas */ for (d = Dump_template; d->area; d++) { write(fd, &d->area, sizeof d->area); i = d->count; write(fd, d->area, i); } close(fd); } /* ** RESTORE GAME ** ** The game is restored from the file "trek.dump". In order for ** this to succeed, the file must exist and be readable, must ** have the correct version number, and must have all the appro- ** priate data areas. ** ** Return value is zero for success, one for failure. */ restartgame() { register int fd; int version; if ((fd = open("trek.dump", 0)) < 0 || read(fd, &version, sizeof version) != sizeof version || version != VERSION || readdump(fd)) { printf("cannot restart\n"); close(fd); return (1); } close(fd); return (0); } /* ** READ DUMP ** ** This is the business end of restartgame(). It reads in the ** areas. ** ** Returns zero for success, one for failure. */ readdump(fd1) int fd1; { register int fd; register struct dump *d; register int i; int junk; fd = fd1; for (d = Dump_template; d->area; d++) { if (read(fd, &junk, sizeof junk) != sizeof junk) return (1); if (junk != d->area) return (1); i = d->count; if (read(fd, d->area, i) != i) return (1); } /* make quite certain we are at EOF */ return (read(fd, &junk, 1)); }