Re: [PATCH v2 1/8] pack-objects: create new name-hash function version

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Junio C Hamano <gitster@xxxxxxxxx> writes:

> karthik nayak <karthik.188@xxxxxxxxx> writes:
>
>> 2. Generally in hashing algorithms the XOR is used to ensure that the
>> output distribution is uniform which reduces collisions. Here, as you
>> noted, we're more finding values for sorting rather than hashing in the
>> traditional sense. So why use an XOR?
>
> I am not Jonathan, but since the mixing-of-bits is done with XOR in
> the original that Linus and I wrote, I think the question applies to
> our version as well.  We prefer not to lose entropy from input
> bytes, so we do not want to use OR or AND, which tend to paint
> everything with 1 or 0 as you mix in bits from more bytes.
>

Thanks for the answering. My reasoning at the start was more of my
thoughts on why XOR could be used here and your explanation makes it
clearer.

> Anyway the question sounds like "generally when you take tests you
> write with a pencil, but right now you are merely taking notes and
> not taking any tests. why are you writing with a pencil?"  There are
> multiple occasions that a pencil is a great fit as writing equipment.

I'd say my questions was more of "I know a pencil is used when taking
tests because of XYZ reasons. On similar lines, why is a pencil used
here?" :)

Attachment: signature.asc
Description: PGP signature


[Index of Archives]     [Linux Kernel Development]     [Gcc Help]     [IETF Annouce]     [DCCP]     [Netdev]     [Networking]     [Security]     [V4L]     [Bugtraq]     [Yosemite]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux SCSI]     [Fedora Users]

  Powered by Linux