#! perl -slw
use strict;

package Buses;

sub new {
	my( $class, $timeTablesObj ) = @_;
	return bless \$timeTablesObj, $class;
}

sub getTimeTable {
	my( $self, $id ) = @_;
	return $$self->get( $id );
}

sub setTimeTable {
	my( $self, $id, $new ) = @_;
	return $$self->set( $id, $new );
}


package Timetables;

sub new{ 
	my( $class, $timetable ) = @_;
	return bless \$timetable, $class;
}

sub get{ 
	my( $self, $id ) = @_; ## Numeric ID, zero based
	return substr $$self, $id*80, 80;
}

sub set{
	my( $self, $id, $new ) = @_;
	substr $$self, $id*80, 80, pack 'a80', $new;
}

package main;

my %buses = map {
	my $timeTable = Timetables->new( 
		join '', map{ pack 'A80', $_ } 0 .. 33
	);
	( "BusID:$_", Buses->new( $timeTable ) );
} 1 .. 50_000;


print $buses{ "BusID:49001" }->getTimeTable( 29 );
<STDIN>;