/*      @(#)dumpgame.c  8.1 (Berkeley) 5/31/93                          */
/*      $NetBSD: dumpgame.c,v 1.15 2009/08/12 08:54:54 dholland Exp $   */

/*
 * Copyright (c) 1980, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <stdio.h>
#include <err.h>
#include <unistd.h>
#include <fcntl.h>
#include "trek.h"

/***  THIS CONSTANT MUST CHANGE AS THE DATA SPACES CHANGE ***/
#define VERSION         2

struct dump {
        char    *area;
        int     count;
};

static int readdump(int);


static struct dump Dump_template[] = {
        { (char *)&Ship,        sizeof (Ship) },
        { (char *)&Now,         sizeof (Now) },
        { (char *)&Param,       sizeof (Param) },
        { (char *)&Etc,         sizeof (Etc) },
        { (char *)&Game,        sizeof (Game) },
        { (char *)Sect,         sizeof (Sect) },
        { (char *)Quad,         sizeof (Quad) },
        { (char *)&Move,        sizeof (Move) },
        { (char *)Event,        sizeof (Event) },
        { NULL,                 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.
*/

/*ARGSUSED*/
void
dumpgame(int v __unused)
{
        int             version;
        int             fd;
        struct dump     *d;
        int             i;

        if ((fd = creat("trek.dump", 0644)) < 0) {
                warn("cannot open `trek.dump'");
                return;
        }
        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.
*/

int
restartgame(void)
{
        int     fd;
        int             version;

        if ((fd = open("trek.dump", O_RDONLY)) < 0 ||
            read(fd, &version, sizeof version) != sizeof version ||
            version != VERSION ||
            readdump(fd)) {
                printf("cannot restart\n");
                if (fd >= 0)
                        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.
*/

static int
readdump(int fd1)
{
        int             fd;
        struct dump     *d;
        int             i;
        long                    junk;

        fd = fd1;

        for (d = Dump_template; d->area; d++) {
                if (read(fd, &junk, sizeof junk) != (sizeof junk))
                        return (1);
                if ((char *)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));
}