knx/examples/knx-linux-coupler/fdsk.h

#pragma once

#include <stdint.h>

class FdskCalculator
{
    public:
        int snprintFdsk(char* str, int strSize, uint8_t* serialNumber, uint8_t* key);

    private:
        char* generateFdskString(uint8_t* serialNumber, uint8_t* key);

        int toBase32(uint8_t* in, long length, uint8_t*& out, bool usePadding);
        int fromBase32(uint8_t* in, long length, uint8_t*& out);

        uint8_t crc4Array(uint8_t* data, uint8_t len)
        {
            uint8_t start = 0;

            for (uint8_t i = 0; i < len; i++)
            {
                start = crc4(start, data[i]);
            }

            return start;
        }

        uint8_t crc4(uint8_t c, uint8_t x)
        {
            uint8_t low4Bits = x & 0x0F;
            uint8_t high4Bits = x >> 4;
            c = crc4_tab[c ^ high4Bits];
            c = crc4_tab[c ^ low4Bits];

            return c;
        }

        int ceil(float num);

        static const uint8_t crc4_tab[16];
};