create_data_packet

unsigned char create_data_packet (char* buffer, int* buffer_size, int n, char *file_name, int filesize)
{
    *buffer_size = strlen(filname) + 4;

    buffer[0] = (char) 1;
    buffer[1] = (char) n;

    int L2 = (int) (packetsize*8/ 256);
    int L1 = (int) (packetsize*8)-L2*256;

    buffer[2] = (char) L2;
    buffer[3]= (char) L1;

    int i=0;
    for(;i<strlen(file_name); i++){
        buffer[4+i]=file_name[i];
    }

    char BCC2;

    BCC2 = buffer[0];
    for (i = 1; i < strlen(file_name) + 4; i++)
        BCC2 ^= buffer[i];

    return BCC2;

}