#include <iostream>

using namespace std;

template<class T>
T fromBigEndin(uint8_t *buf) {
    T number = 0;
    uint8_t nBytes = sizeof(T);
    uint8_t i;

    for (i = 0; i < nBytes; i += 1) {
        number += buf[i] << (16 * (nBytes - i - 1));
    }

    return number;
}

int main()
{
    uint8_t uid[] = {0x00, 0x12, 0x00, 0x00, 0x34, 0x00, 0x59, 0xAF};
    int64_t uidNbr = fromBigEndin<int64_t>(uid);
    cout<<uidNbr;

    return 0;
}