todigits.cpp

        static uint8_t DigitsCount(uint64_t v)
        {
                for (uint8_t res{1}; ;res+=4, v/=10000U)
                {
                        if (likely(v < 10)) return res;
                        if (likely(v < 100)) return res + 1;
                        if (likely(v < 1000)) return res + 2;
                        if (likely(v < 10000)) return res + 3;
                }
        }

uint8_t U32ToASCII(uint32_t v, char *const dst)
{       
        const auto result = DigitsCount(v);
        uint32_t pos = result - 1;
                
        while (v >= 10)
        {       
                const auto q = v / 10;
                const auto r = static_cast<uint32_t>(v % 10);
        
                dst[pos--] = '0' + r;
                v = q;
        }
        dst[pos] = static_cast<uint32_t>(v) + '0';
        return result;
}