# This way of dealing with meg and gig is a poor way, used only for demonstration.
# Supersearch for a better way.
my $KB = 1024;
my $MB = 1024 * $KB;
my $GB = 1024 * $MB;
my %Classes = (
    $MB => 'BitStream::Vec',
    $GB => 'BitStream::Buffered',
);

my $filesize = -s $filename;

my $classname = 'BitStream::InMemory';
foreach my $min_size (sort { $a <=> $b } keys %Classes)
{
    last unless $filesize >= $min_size;
    $classname = $classes{$min_size};
}

my $stream = $classname->new($filename);