/ 
String-CityHash-0.06
/ String::CityHash

NAME

String::CityHash - CityHash wrapper for Perl

VERSION

version 0.06

SYNOPSIS

use String::CityHash qw(cityhash64 cityhash128);

my $str = "Some string to be hashed";

my $seed0 = 0x9ae16a3b2f90404f;
my $seed1 = 0xc3a5c85c97cb3130;

my $hash1 = cityhash64($str);                 # as integer
my $hash2 = cityhash64($str, $seed0);         # as integer
my $hash3 = cityhash64($str, $seed0, $seed1); # as integer

my $hash4 = cityhash64_bits($str);            # 8-byte string holding int
my $hash5 = cityhash64_bits($str, $seed0);
my $hash6 = cityhash64_bits($str, $seed0, $seed1);

my ($l,$h) = cityhash128($str);               # low and high 64-bit parts,
                                              # as integers

my $hash7  = cityhash128_bits($str);          # 16-byte string holding low
                                              # then high 64-bit integers

DESCRIPTION

CityHash is a family of non-cryptographic hash functions for strings. It provides hash functions designed for fast hashing of strings. The functions mix the input bits thoroughly but are not suitable for cryptography. CityHash is intended to be fast, under the constraint that it hashes very well.

EXPORTS

This module exports the subroutines cityhash64, cityhash64_bits, cityhash128 and cityhash128_bits on request.

SUBROUTINES

cityhash64( $data [, $seed0 [, $seed1 ] ] )

Generate a 64-bit hash for the given data. The optional one or two 64-bit seeds are also hashed into the result.

cityhash64_bits( $data [, $seed0 [, $seed1 ] ] )

Likewise, but returns 8-byte binary string of hash in network byte order.

cityhash128( $data )

Generate a 128-bit hash for the given data. Returns list of the low and high 64-bit portions of the hash. In scalar context returns only the low portion.

cityhash128_bits( $data )

Generate a 128-bit hash for the given data. Returns 16-byte binary string containing the low 64 bits then high 64 bits; each 8-byte portion is in network byte order. Extract with e.g. unpack 'Q2'>.

ACKNOWLEDGMENTS

Since version 0.06 cityhash128 returns either a list of the high and low portions of the 128-bit hash (in list context), or only the 64-bit low portion of the hash (in scalar context).

AUTHOR

Alessandro Ghedini <alexbio@cpan.org>

SEE ALSO

CityHash

LICENSE AND COPYRIGHT

Copyright 2011 Alessandro Ghedini.

This program is free software; you can redistribute it and/or modify it under the terms of either: the GNU General Public License as published by the Free Software Foundation; or the Artistic License.

See http://dev.perl.org/licenses/ for more information.