NAME
Digest::xxHash - xxHash Implementation For Perl
SYNOPSIS
use Digest::xxHash qw[xxhash32 xxhash32_hex xxhash64 xxhash64_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
xxHash is an extremely fast algorithm that claims to work at speeds
close to RAM limits. This is a wrapper of both the 32- and 64-bit hash
functions.
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.
