[Python-Dev] bitwise operations for bytes and bytearray

[Brett Cannon]

On Thu, 7 Jan 2016 at 14:29 Blake Griffith <blake.a.griffith at gmail.com>
wrote:

> Hi!
>
> I'm interested in adding the functionality to do something like:
>
> >>>  b'a' ^ b'b'
> b'\x03'
>
>
> Instead of the good ol' TypeError.
>
> I think both bytes and bytearray should support all the bitwise operations.
>
> I've never hacked on cpython before. I'm starting by just trying to add
> xor to bytearray. I have a ByteArray_Xor function that I think should do
> this here
> https://github.com/cowlicks/cpython/commit/d6dddb11cdb33032b39dcb9dfdaa7b10d4377b5f
>
> But I'm not sure how to hook this in to the rest of cypython. I tried
> adding it where bytearray_as_sequence is declared in this
> bytearrayobject.c file. But that gave me compiler warnings and broke things.
>
> So now that I have this ByteArray_Xor function, how do I make it be
> bytearray.__xor___?
>

You need to set the PyNumberMethods struct with the appropriate function
and then set that on the PyTypeObject. Look at
https://hg.python.org/cpython/file/tip/Include/object.h#l237 and
https://hg.python.org/cpython/file/tip/Objects/longobject.c#l5238 for an
idea of what it takes.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/python-dev/attachments/20160107/92a37da2/attachment.html>