sub new {
    my $class = shift;
    my $self  = bless(
        {
            'diskNumber'                            => 0,
            'diskNumberWithStartOfCentralDirectory' => 0,
            'numberOfCentralDirectoriesOnThisDisk'  => 0, # shld be # of members
            'numberOfCentralDirectories'            => 0, # shld be # of members
            'centralDirectorySize' => 0,    # must re-compute on write
            'centralDirectoryOffsetWRTStartingDiskNumber' =>
              0,                            # must re-compute
            'writeEOCDOffset'             => 0,
            'writeCentralDirectoryOffset' => 0,
            'zipfileComment'              => '',
            'eocdOffset'                  => 0,
            'fileName'                    => ''
        },
        $class
    );
    $self->{'members'} = [];
    my $fileName = ( ref( $_[0] ) eq 'HASH' ) ? shift->{filename} : shift;
    if ($fileName) {
        my $status = $self->read($fileName);
        return $status == AZ_OK ? $self : undef;
    }
    return $self;
}