use DateTime;
use Moose;

# The raw data that all the fields are extracted from.
has 'rawDataBlock' => (
      is  => 'rw',
      isa => 'Str',
);

# All the fields extracted from the raw data block are lazy using builders below.
has 'lastPlay'        => ( lazy_build => 1, is=>'rw', isa=>'Int');
has 'ChanNum'         => ( lazy_build => 1, is=>'rw', isa=>'Int');
has 'startTime'       => ( lazy_build => 1, is=>'rw', isa=>'DateTime');
has 'fileName'        => ( lazy_build => 1, is=>'rw', isa=>'Str');

[...]

sub _build_lastPlay
{
    my $self = shift @_;
    return unpack('@5 S', $self->rawDataBlock() );
}

sub _build_ChanNum
{
    my $self = shift @_;
    return unpack('@17 S', $self->rawDataBlock() );
}

sub _build_startTime
{
    my $self = shift @_;
    my $epoch = unpack('@25 N', $self->rawDataBlock() );
    return DateTime->from_epoch( epoch => $epoch, time_zone => 'GMT' );
}

sub _build_fileName
{
    my $self = shift @_;
    return unpack('@33 A512', $self->rawDataBlock() );
}