Convert a hex string into integer or character buffer

dehex.c

static inline char _hexify(const char c)
{
    return (((c | ('A' ^ 'a')) - '0') % 39);
}

/// Converts a len-digit hex number into its unsigned native representation.
unsigned int dehex_to_int(int ilen, const char ibuf[ilen])
{
    unsigned int result = 0;

    for (int i = 0; i < ilen; i++)
        result |= _hexify(ibuf[ilen - i - 1]) << (i << 2);

    return result;
}

void dehex_to_buf(int ilen, const char ibuf[ilen], int olen, char obuf[olen])
{
    for (int i = 0; i < ilen && i >> 1 < olen; i++)
        obuf[i >> 1] |= _hexify(ibuf[ilen - i - 1]) << ((i & 1) << 2);
}