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# -*- Perl -*-
#
# Toy deterministic separate chain hash implementation, based on code in
# "Algorithms (4th Edition)" by Robert Sedgewick and Kevin Wayne. This
# code is not for any sort of use where performance is critical, or
# where malicious input may cause "Algorithmic Complexity Attacks" (see
# perlsec(1)).
#
# run perldoc(1) on this file for additional documentation

package Algorithm::Toy::HashSC;

use 5.010;
use strict;
use warnings;

use Carp qw/croak/;

lib/Algorithm/Toy/HashSC.pm  view on Meta::CPAN

left as an exercise to the reader, probably music or artwork where the
particulars of the hash code and modulus groups the data in a desired
manner; this ordering or grouping can help determine e.g. pitch sets,
rhythmic material, etc. Hence, the B<keys_in> and B<keys_with> methods
to obtain the keys in a chain, or with a particular key. Variety could
be added by varying the modulus, or changing the B<hash> or
B<hashcode> methods.

This module is not for use where performance is a concern, or where
untrusted user input may be supplied for the key material.
L<perlsec/"Algorithmic Complexity Attacks"> discusses why Perl's hash
are no longer deterministic and thus not suitable for deterministic
music composition.

=head1 CONSTRUCTOR

The B<new> method accepts any of the L</"ATTRIBUTES">.

=head1 ATTRIBUTES

=over 4

lib/Algorithm/Toy/HashSC.pm  view on Meta::CPAN

=head2 Known Issues

The default hash code calculation has not been tested to determine how
evenly it spreads keys out across the modulus space. As a workaround,
the hash key can be an object that provides a B<hashcode> method, in
which case this issue falls out of scope of this module.

=head1 SEE ALSO

L<perlsec/"Algorithmic Complexity Attacks"> - details on why Perl's hash
do not behave so simply as that of this module do.

"Algorithms" (4th Edition) by Robert Sedgewick and Kevin Wayne.

L<Hash::Util> - insight into Perl's hashes.

The "smhasher" project may help verify whether B<hashcode> functions are
as perfect as possible.

=head1 COPYRIGHT AND LICENSE