//#include <io.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <sys/mtio.h>

int fh;
struct mtget stblk;
struct mtop  opblk;

#define BLKLEN 512
#define RBLKLEN 512
//#define RBLKLEN 65535 // var blks only

char buf [BLKLEN] = "0123456789";

void disp_stat () {
    int  stat;
    char buf [256];

    ioctl (fh, MTIOCGET, (char*)&stblk);
    stat = stblk.mt_gstat;

    /* Display tape status */
    sprintf (buf, "Status: %8.8X", stat);
    if (GMT_EOF(stat)) strcat (buf, " EOF");
    if (GMT_BOT(stat)) strcat (buf, " BOT");
    if (GMT_EOT(stat)) strcat (buf, " EOT");
    if (GMT_SM(stat)) strcat (buf, " SET-MARK");
    if (GMT_EOD(stat)) strcat (buf, " EOD");
    if (GMT_WR_PROT(stat)) strcat (buf, " WR-PROT");
    if (GMT_ONLINE(stat)) strcat (buf, " ON-LINE");
    if (GMT_D_6250(stat)) strcat (buf, " 6250");
    if (GMT_D_1600(stat)) strcat (buf, " 1600");
    if (GMT_D_800(stat)) strcat (buf, " 800");
    if (GMT_DR_OPEN(stat)) strcat (buf, " NO-TAPE");

    printf ("ST0: %s\n", buf);
};

void common () {
    printf ("stblk.mt_blkno=%d\n", stblk.mt_blkno);
};

void set_blk (int len) {
    int rc;

    if (len)
        printf ("Setting length %d records.", len);
    else
        printf ("Setting variable records.");
    fflush (stdout);

    opblk.mt_op = MTSETBLK;
    opblk.mt_count = len;
    rc = ioctl (fh, MTIOCTOP, (char*)&opblk);

    printf (" rc=%d\n", rc);
};

void my_read (int fh) {
    int rc;
    int en;
    char buf2 [RBLKLEN];

    printf ("read...");
    fflush (stdout);
    memset (buf2, ' ', 10);

    errno = 0;
    rc = read (fh, buf2, RBLKLEN);
    en = errno;

    printf (" rc=%d, errno=%d\n", rc, en);
    buf2 [10] = 0;
    printf ("%s\n", buf2);
    disp_stat ();
    common ();
};

void my_read1 (int fh) {
    int rc;
    int en;
    char buf2 [1];

    printf ("read1...");
    fflush (stdout);
    memset (buf2, ' ', 10);

    errno = 0;
    rc = read (fh, buf2, 1);
    en = errno;

    printf (" rc=%d, errno=%d\n", rc, en);
    buf2 [1] = 0;
    printf ("%s\n", buf2);
    disp_stat ();
    common ();
};

void my_write (int fh) {
    int rc;
    int en;

    printf ("write...");
    fflush (stdout);

    errno = 0;
    rc = write (fh, buf, BLKLEN);
    en = errno;

    printf (" rc=%d, errno=%d\n", rc, en);
    disp_stat ();
    common ();
};

void my_bksp (int fh) {
    int rc;

    printf ("backspace...");
    fflush (stdout);
    opblk.mt_op = MTBSR;
    opblk.mt_count = 1;
    rc = ioctl (fh, MTIOCTOP, (char*)&opblk);
    printf (" rc=%d\n", rc);
    disp_stat ();
    common ();
};

void my_rew (int fh) {
    int rc;

    printf ("rewind...");
    fflush (stdout);
    opblk.mt_op = MTREW;
    opblk.mt_count = 1;
    rc = ioctl (fh, MTIOCTOP, (char*)&opblk);
    printf (" rc=%d\n", rc);
    disp_stat ();
};

int main (int argc) {
    int rc;

    printf ("Opening Tape Handle\n");

    fh = open ("/dev/st0", O_RDWR);
    if (fh >= 0) {

        rc = ioctl (fh, MTIOCGET, (char*)&stblk);
        if (rc < 0) {
            printf ("Failed to IOCTL the Tape\n");
        } else {
            common ();
        };

        disp_stat ();
        set_blk (BLKLEN);
        disp_stat ();
        my_rew (fh);

        buf [0] = 'A';
        buf [1] = 'C';
        my_write (fh);
        my_bksp (fh);

        if (argc == 1)
            my_read (fh);
        else
            my_read1 (fh); // special 1 char read

        buf [0] = 'B';
        buf [1] = 'D';
        my_write (fh);
        my_bksp (fh);
        my_read (fh);
        my_rew (fh);

        printf ("Closing Tape Handle\n");
        close (fh);

    } else {

        printf ("Failed to Open Tape\n");
    };

    return (0);
};