/*======================================================================*
 *      DOSshell program to calculate a CRC checksum on a file.         *
 *======================================================================*/

#version        $50
#reserve        6
#copyright      "Crc.cmd        Copyright 1995 K-Products"
#address        $7000

#include        runtime.h
#include        bbs_pro.h

#define         MAXBUFF 17408
#define         DISK2   2
#define         DISK4   4


char    buffer [MAXBUFF];


main()
{
    heading();
    if (length (parm1) == 0) {
        echose("Usage: CRC filename.ext");
        return;
    }
    crc_file();
}



heading()
{
    cr_lf();
    echose("BBS Express! Pro            CRC v5.0");
    echose("       (c) 1995 K-Products");
    cr_lf();
}



crc_file()
{
    int  crc, bytesin;

    echos("Reading, ");
    zero (buffer, sizeof(buffer));
    MIOsuspend();
    if (open (DISK2, parm1, 4, 0) != OK) {      /* open input file?     */
        MIOresume();
        echose("Unable to open input file!");
        return;
    }
    bytesin = blockread (DISK2, buffer, sizeof(buffer));
    if (IOresult (DISK2) != 136) {
        MIOresume();
        cr_lf();
        cr_lf();
        echose("Unable to read file (too big?)");
        return;
    }
    close (DISK2);
    MIOresume();
    echos("calculating, ");
    crc = calc_CRC (buffer, bytesin);           /* use xmodem's routine */
    echos ("CRC is $");
    hexword (crc);
    cr_lf();
}



hexword (int i)
{
    hexbyte(i >> 8);
    hexbyte(i & $ff);
}



hexbyte (char c)
{
    char hexdig [20];

    strcpy(hexdig,"0123456789ABCDEF");
    echo (hexdig [c >> 4 + 1]);
    echo (hexdig [c & $0f + 1]);
}