/*

The following is the simple algorithm used by Quake 3 to check the CD-Keys

by Luigi Auriemma
e-mail: aluigi@autistici.org
web:    aluigi.org

*/


#define OKKO    "\x00\x00\x01\x01\x01\x00\x01\x01" \
                "\x01\x01\x01\x01\x01\x01\x01\x00" \
                "\x00\x00\x00\x01\x01\x00\x00\x01" \
                "\x00\x01\x00\x01\x01\x01\x00\x01" \
                "\x00\x00\x00\x01\x01\x00"

/* OKKO:           */
/* if 0: ok        */
/* if 1: wrong key */




    char           cdkey[],    // cdkey of 16 chars (0-9, A-Z)
                   *ptr;       // pointer
    int            i;          // counter
    unsigned char  ecx;        // register


    ptr = cdkey;
    for(i = 0; i < 16; i++) {
        if((*ptr >= 0x61) && (*ptr <= 0x7a)) *ptr -= 32;
        ecx = *ptr - 0x32;
        if(ecx > 0x25) break;
        if(OKKO[ecx]) break;
        ptr++;
    }

    if(i == 16) fputs("\nYour Cd-Key is OK\n", stdout);
        else fputs("\nYour Cd-Key is invalid\n", stdout);