Convert char array to hex array (C++)

Question

My problem is converting array of chars to array of hexadecimal numbers, i need to take 2chars from char array and conver them into one hex number.

This is my input:

Answer 1

Some easy implementations

unsigned char text[1024] = "06fb7405eba8d9e94fb1f28f0dd21fdec55fd54750ee84d95ecccf2b1b48";
unsigned char result[512];

int size = 60;

assert(size % 2 == 0);

for (int i = 0; i + 1 < size; i += 2)
{
    std::string s(text + i, text + i + 2);
    auto x = std::stoi(s, 0, 16);
    result[i / 2] = x;
}
// or
for (int i = 0; i + 1 < size; i += 2)
{
    unsigned char c1 = *(text + i);
    unsigned char c2 = *(text + i + 1);
    char buffer[] = { c1, c2, 0 };
    auto x = std::strtol(buffer, 0, 16);
    result[i / 2] = x;
}

In this case the result is the half size of the input. Two chars are leading to one value in the result. If this is a time critical routine you may write your own conversion from two chars in a number.