Function x2c

library/cpp/string_utils/url/url.cpp:392–396

#define X(c) (c >= 'A' ? ((c & 0xdf) - 'A') + 10 : (c - '0'))

static inline int x2c(unsigned char* x) {
    if (!IsAsciiHex(x[0]) || !IsAsciiHex(x[1]))
        return -1;
    return X(x[0]) * 16 + X(x[1]);
}

#undef X