NAME
Digest::xxHash - xxHash Implementation For Perl
SYNOPSIS
use Digest::xxHash qw[xxhash32 xxhash32_hex];
my $hash = xxhash32( $data, $seed );
my $hex = xxhash32_hex( $data, $seed );
my $hash_64 = xxhash64( $data, $seed );
my $hex_64 = xxhash64_hex( $data, $seed );
DESCRIPTION
This module provides both a functional and an object oriented interface
to xxHash functions. xxHash is an extremely fast algorithm that claims
to work at speeds close to RAM limits.
FUNCTIONAL INTERFACE
These functions are easy to use but aren't very flexible.
$h = xxhash32( $data, $seed )
Calculates a 32 bit hash.
$h = xxhash32_hex( $data, $seed )
Calculates a 32 bit hash and returns it as a hex string.
$h = xxhash64( $data, $seed )
Calculates a 64 bit hash.
$h = xxhash64_hex( $data, $seed )
Calculates a 64 bit hash and returns it as a hex string.
SPEED
According to the xxhash project's website, when run in a single thread
on a 32bit Windows 7 box with a 3GHz Core 2 Duo processor, xxhash looks
a little like:
Name Speed Q.Score Author
xxHash 5.4 GB/s 10
CrapWow 3.2 GB/s 2 Andrew
MumurHash 3a 2.7 GB/s 10 Austin Appleby
SpookyHash 2.0 GB/s 10 Bob Jenkins
SBox 1.4 GB/s 9 Bret Mulvey
Lookup3 1.2 GB/s 9 Bob Jenkins
SuperFastHash 1.2 GB/s 1 Paul Hsieh
CityHash64 1.05 GB/s 10 Pike & Alakuijala
FNV 0.55 GB/s 5 Fowler, Noll, Vo
CRC32 0.43 GB/s 9
MD5-32 0.33 GB/s 10 Ronald L. Rivest
SHA1-32 0.28 GB/s 10
Q.Score is a measure of "quality" of the hash function. It depends on
successfully passing SMHasher test set
<
http://code.google.com/p/smhasher/wiki/SMHasher>. 10 is a perfect
score. Hash functions with a Q.score < 5 are not listed in this table.
A 64-bits version, named XXH64, is available since (upstream) r35. It
offers much better speed, but for 64-bits applications only.
Name Speed on 64 bits Speed on 32 bits
XXH64 13.8 GB/s 1.9 GB/s
XXH32 6.8 GB/s 6.0 GB/s
LICENSE
xxHash is covered by the BSD license.
License-wise, I don't actually care about the wrapper I've written.
AUTHOR
Sanko Robinson <
[email protected]>
xxHash by Yann Collet.
