[Python-Dev] [Python-checkins] cpython: Issue #14814: addition of the ipaddress module (stage 1 (original) (raw)

Terry Reedy tjreedy at udel.edu
Sun May 20 19🔞29 CEST 2012

On 5/20/2012 7:02 AM, nick.coghlan wrote:

+def ipaddress(address, version=None): + """Take an IP string/int and return an object of the correct type. + + Args: + address: A string or integer, the IP address. Either IPv4 or + IPv6 addresses may be supplied; integers less than 2**32 will + be considered to be IPv4 by default. + version: An Integer, 4 or 6. If set, don't try to automatically

integer, not Integer

+ determine what the IP address type is. important for things + like ipaddress(1), which could be IPv4, '192.0.2.1', or IPv6, + '2001:db8::1'.

I read this as saying that a version other than 4 or 6 should be an error, and not ignored as if not set. If version is set incorrectly, it is still set. I certainly would expect an error to be an error.

+ + Returns: + An IPv4Address or IPv6Address object. + + Raises: + ValueError: if the string passed isn't either a v4 or a v6 + address.

Should say "if the address...", and I suggest adding "or if the version is not None, 4, or 6."

+ + """ + if version:

if version is not None: ?? Do you really want to silently ignore every null value, like '' or []?

+ if version == 4: + return IPv4Address(address) + elif version == 6: + return IPv6Address(address)

else: raise ValueError() ??

...

+def ipnetwork(address, version=None, strict=True): + """Take an IP string/int and return an object of the correct type. + + Args: + address: A string or integer, the IP network. Either IPv4 or + IPv6 networks may be supplied; integers less than 2**32 will + be considered to be IPv4 by default. + version: An Integer, if set, don't try to automatically + determine what the IP address type is. important for things + like ipnetwork(1), which could be IPv4, '192.0.2.1/32', or IPv6, + '2001:db8::1/128'.

Same comments

+def ipinterface(address, version=None): + """Take an IP string/int and return an object of the correct type. + + Args: + address: A string or integer, the IP address. Either IPv4 or + IPv6 addresses may be supplied; integers less than 2**32 will + be considered to be IPv4 by default. + version: An Integer, if set, don't try to automatically + determine what the IP address type is. important for things + like ipnetwork(1), which could be IPv4, '192.0.2.1/32', or IPv6, + '2001:db8::1/128'.

ditto

+ Returns: + An IPv4Network or IPv6Network object.

Interface, not Network

+def v4inttopacked(address): + """The binary representation of this address.

Since integers are typically implemented as strings of binary bits, a 'binary representation' could mean a string of 0s and 1s.

+ + Args: + address: An integer representation of an IPv4 IP address. + + Returns: + The binary representation of this address.

The integer address packed as 4 bytes in network (big-endian) order.

+ Raises: + ValueError: If the integer is too large to be an IPv4 IP + address.

And if the address is too small (negative)? "If the integer is negative or ..." ?

+ """ + if address> BaseV4.ALLONES:

or address < 0?

+ raise ValueError('Address too large for IPv4') + return struct.pack('!I', address)

It is true that struct will raise struct.error: argument out of range for negative addresses, but it will also also do the same for too large addresses. So either let it propagate or catch it in both cases. For the latter (assuming the max is the max 4 byte int):

try: return struct.pack('!I', address) except struct.error: raise ValueError("Address negative or too large for IPv4")

+ +def v6inttopacked(address): + """The binary representation of this address.

Similar comments, except packed into 16 bytes

+ Args: + address: An integer representation of an IPv4 IP address. + + Returns: + The binary representation of this address. + """ + return struct.pack('!QQ', address>> 64, address& (2**64 - 1))

Why no range check? Here you are letting struct.error propagate.

+ +def findaddressrange(addresses): + """Find a sequence of addresses.

An 'address' can in various places be a string, int, bytes, IPv4Address, or IPv6Address. For neophyte users, I think you should be clear each time you use 'address'. From the code, I conclude it here means the latter two.

+ + Args: + addresses: a list of IPv4 or IPv6 addresses.

a list of IPv#Address objects.

+def getprefixlength(number1, number2, bits): + """Get the number of leading bits that are same for two numbers. + + Args: + number1: an integer. + number2: another integer. + bits: the maximum number of bits to compare. + + Returns: + The number of leading bits that are the same for two numbers. + + """ + for i in range(bits): + if number1>> i == number2>> i:

This non-PEP8 spacing is awful to read. The double space after the tighter binding operator is actively deceptive. Please use if number1 >> i == number2 >> i:

+ if (number>> i) % 2:

ditto

+def summarizeaddressrange(first, last):

+ Args: + first: the first IPv4Address or IPv6Address in the range. + last: the last IPv4Address or IPv6Address in the range. + + Returns: + An iterator of the summarized IPv(4|6) network objects.

Very clear as to types.

+ while firstint<= lastint:

PEP8: while first_int <= last_int: is really much easier to read.

+ while nbits>= 0:

ditto, etcetera through rest of file.

+ while mask: + if ipint& 1 == 1:

Instead of no space and then 2 spaces, use uniform 1 space around &

         if ip_int & 1 == 1:

+ ipint>>= 1

To me, augmented assignments need a space before and after even more than plain assignments, especially with underscored names.

ip_int >>= 1

I am guessing that Peter dislikes putting ' ' before '<' and '>' and perhaps '&', but it makes code harder to read. Putting an extra space after is even worse.

This is as far as I read. Some of the style changes could be done with global search and selective replace.

Terry Jan Reedy

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