def inet_ntoa()

in functions/source/populate_NLB_TG_with_ALB/dns/ipv6.py [0:0]

• 51 lines of code
• 3 McCabe index (conditional complexity)

def inet_ntoa(address):
    """Convert a network format IPv6 address into text.

    @param address: the binary address
    @type address: string
    @rtype: string
    @raises ValueError: the address isn't 16 bytes long
    """

    if len(address) != 16:
        raise ValueError("IPv6 addresses are 16 bytes long")
    hex = binascii.hexlify(address)
    chunks = []
    i = 0
    l = len(hex)
    while i < l:
        chunk = hex[i : i + 4]
        # strip leading zeros.  we do this with an re instead of
        # with lstrip() because lstrip() didn't support chars until
        # python 2.2.2
        m = _leading_zero.match(chunk)
        if not m is None:
            chunk = m.group(1)
        chunks.append(chunk)
        i += 4
    #
    # Compress the longest subsequence of 0-value chunks to ::
    #
    best_start = 0
    best_len = 0
    start = -1
    last_was_zero = False
    for i in xrange(8):
        if chunks[i] != b'0':
            if last_was_zero:
                end = i
                current_len = end - start
                if current_len > best_len:
                    best_start = start
                    best_len = current_len
                last_was_zero = False
        elif not last_was_zero:
            start = i
            last_was_zero = True
    if last_was_zero:
        end = 8
        current_len = end - start
        if current_len > best_len:
            best_start = start
            best_len = current_len
    if best_len > 1:
        if best_start == 0 and \
           (best_len == 6 or
            best_len == 5 and chunks[5] == b'ffff'):
            # We have an embedded IPv4 address
            if best_len == 6:
                prefix = b'::'
            else:
                prefix = b'::ffff:'
            hex = prefix + dns.ipv4.inet_ntoa(address[12:])
        else:
            hex = b':'.join(chunks[:best_start]) + b'::' + \
                  b':'.join(chunks[best_start + best_len:])
    else:
        hex = b':'.join(chunks)
    return maybe_decode(hex)