JHash.pm



NAME

Digest::JHash - Perl extension for 32 bit Jenkins Hashing Algorithm


SYNOPSIS

    use Digest::JHash qw(jhash);
    $digest = jhash($data);
    # note that calling jhash() directly like this is the fastest way:
    $digest = Digest::JHash::jhash($data);


DESCRIPTION

The Digest::JHash module allows you to use the fast JHash hashing algorithm developed by Bob Jenkins from within Perl programs. The algorithm takes as input a message of arbitrary length and produces as output a 32-bit "message digest" of the input in the form of an unsigned long integer.

Call it a low calorie version of MD5 if you like.

See http://burtleburtle.net/bob/hash/doobs.html for more information.


FUNCTIONS

jhash($data)

This function will calculate the JHash digest of the "message" in $data and return a 32 bit integer result (an unsigned long in the C)


EXPORTS

None by default but you can have the jhash() function if you ask nicely. See below for reasons not to use Exporter (it is slower than a direct call)


SPEED NOTE

If speed is a major issue it is roughly twice as fast to do call the jhash() function like Digest::JHash::jhash('message') than it is to import the jhash() method using Exporter so you can call it as simply jhash('message'). There is a short script that demonstrates the speed of different calling methods (direct, OO and Imported) in examples/oo_vs_func.pl


AUTHORS

The JHash implementation was written by Bob Jenkins <bob_jenkins [at] burtleburtle [dot] net>.

This perl extension was written by Andrew Towers <mariofrog [at] bigpond [dot] com>.

A few mods were added by James Freeman <airmedical [at] gmail [dot] com>).


SEE ALSO

http://burtleburtle.net/bob/hash/doobs.html


LICENSE

This package is free software and is provided "as is" without express or implied warranty. It may be used, redistributed and/or modified under the terms of the Artistic License 2.0. A copy is include in this distribution.

 JHash.pm