https://github.com/andikleen/spooky-c

A C version of Bob Jenkins' spooky hash
https://github.com/andikleen/spooky-c

Last synced: 11 days ago
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A C version of Bob Jenkins' spooky hash

• Host: GitHub
• URL: https://github.com/andikleen/spooky-c
• Owner: andikleen
• Created: 2012-04-22T00:37:24.000Z (over 12 years ago)
• Default Branch: master
• Last Pushed: 2017-05-02T13:48:12.000Z (over 7 years ago)
• Last Synced: 2023-03-12T07:06:54.545Z (over 1 year ago)
• Language: C
• Size: 52.7 KB
• Stars: 36
• Watchers: 2
• Forks: 7
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
![spooky-c](http://halobates.de/spooky-c.png)

This is a C version of Bob Jenkins' 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.

Building:

spooky-c.c is a simple C file that you can copy into your project.

If you want to build a shared library you can use autoconf

(Run autoconf ; then ./configure )

If you just want to build the test programs you can also use

Makefile.simple (make -f Makefile.simple)

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)

 

 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.