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https://github.com/dmolik/libspooky

A system libized version of Bob Jenkin's Spooky hash
https://github.com/dmolik/libspooky

Last synced: about 14 hours ago
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A system libized version of Bob Jenkin's Spooky hash

Host: GitHub
URL: https://github.com/dmolik/libspooky
Owner: dmolik
License: gpl-3.0
Created: 2015-02-25T13:00:53.000Z (over 9 years ago)
Default Branch: master
Last Pushed: 2016-06-24T17:47:59.000Z (over 8 years ago)
Last Synced: 2024-04-20T00:29:18.132Z (7 months ago)
Language: C
Size: 352 KB
Stars: 2
Watchers: 3
Forks: 0
Open Issues: 0
Metadata Files:
- Readme: README.md
- License: COPYING

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README

LIBSPOOKY
=========

Libspooky is a C implementation of Bob Jenkin's spooky hash algorithm.

INSTALLATION
------------

To install libspooky from source execute the following steps:

git clone https://github.com/D3fy/libspooky.git
cd libspooky
./bootstrap
./configure
make
make install

DESCRIPTION
-----------

This is a C version of Bob Jenkin's spooky hash. The only advantage over
Bob's original version is that it is in C, not C++ and comes with
some test and benchmark code.

This is a very competitive hash function, but is somewhat unportable
(64bit little endian only). It's more portable than some of the
contenders like CityHash.

Quoting Bobs original description:

SpookyHash: a 128-bit noncryptographic hash function
By Bob Jenkins, public domain

Oct 31 2010: alpha, framework + SpookyHash::Mix appears right
Oct 31 2011: alpha again, Mix only good to 2^^69 but rest appears right
Oct 11 2011: C version ported by Andi Kleen (andikleen@github)
Dec 31 2011: beta, improved Mix, tested it for 2-bit deltas
Feb 2 2012: production, same bits as beta
Feb 5 2012: adjusted definitions of uint* to be more portable
Mar 30 2012: 3 bytes/cycle, not 4. Alpha was 4 but wasn't thorough enough.
Apr 27 2012: C version updated by Ziga Zupanec (agiz@github)
Feb 25 2015: C version converted to system library (graytshirt@github)

Up to 3 bytes/cycle for long messages. Reasonably fast for short messages.
All 1 or 2 bit deltas achieve avalanche within 1% bias per output bit.

This was developed for and tested on 64-bit x86-compatible processors.
It assumes the processor is little-endian. There is a macro
controlling whether unaligned reads are allowed (by default they are).
This should be an equally good hash on big-endian machines, but it will
compute different results on them than on little-endian machines.

Google's CityHash has similar specs to SpookyHash, and CityHash is faster
on some platforms. MD4 and MD5 also have similar specs, but they are orders
of magnitude slower. CRCs are two or more times slower, but unlike
SpookyHash, they have nice math for combining the CRCs of pieces to form
the CRCs of wholes. There are also cryptographic hashes, but those are even
slower than MD5.