Algorithm::BinPack 0.5

Algorithm::BinPack is a Perl module that can efficiently pack items into bins.

SYNOPSIS

Algorithm::BinPack efficiently packs items into bins. The bins are given a maximum size, and items are packed in with as little empty space as possible. An example use would be backing up files to CD, while minimizing the number of discs required.

my $bp = Algorithm::BinPack->new(binsize => 4);

$bp->add_item(label => "one", size => 1);
$bp->add_item(label => "two", size => 2);
$bp->add_item(label => "three", size => 3);
$bp->add_item(label => "four", size => 4);

for ($bp->pack_bins) {
print "Bin size: ", $_->{size}, "n";
print " Item: ", $_->{label}, "n" for @{ $_->{items} };
}

METHODS

new

Creates a new Algorithm::BinPack object. The maximum bin size is specified as a named argument binsize, and is required. A fudge factor may be specified as a named argument fudge. If a fudge factor is specified, item sizes will be rounded up to a number divisible by the fudge factor. This can help keep items with similar sizes in order by their labels.

my $bp = Algorithm::BinPack->new(binsize => 4);
my $bp = Algorithm::BinPack->new(binsize => 100, fudge => 10);

add_item

Adds an item to be packed into a bin. Required named arguments are label and size, but any others can be specified, and will be saved. An optional bin argument can be used to manually put an item into the specified bin.

$bp->add_item(label => one, size => 1);
$bp->add_item(label => two, size => 2, desc => The second numeral);
$bp->add_item(label => zero, size => 3, bin => 0);
$bp->add_item(qw(label three size 3));
$bp->add_item(qw(label four size 4 random key));

prefill_bin

(Deprecated method) add_item now knows how to handle the bin argument directly, so this method is redundant.

pack_bins

Packs the items into bins. This method tries to leave as little empty space in each bin as possible. It returns a list of hashrefs with the key size containing the total bin size, and items containing an arrayref holding the items in the bin. Each item is in turn a hashref containing the keys label, size, and any others added to the item. If a fudge factor was used, each item will contain a key fudgesize, which is the size this item was fudged to.

for my $bin ($bp->pack_bins) {
print "Bin size: ", $bin->{size}, "n";

for my $item (@{ $bin->{items} }) {
printf " %-6s %-20sn", $_, $item->{$_} for keys %{ $item };
print " ---n";
}
}