my $do_data_magic_only_once = undef;
sub new {
    my $self = {};
    my $proto = shift;
    my $class = ref($proto) || $proto;
    $self->{MF} = [];
    $self->{magic} = [];
    if (! @_) {
        if( $do_data_magic_only_once ){
            $self->{magic} = $do_data_magic_only_once;
        } else {
            my $fh = *File::MMagic::DATA{IO};
            binmode($fh);
            bless $fh, 'FileHandle' if ref $fh ne 'FileHandle';
            my $dataLoc;
            # code block to localise the no strict;, contribute by Simon Matthews
            {
                no strict 'refs';
                my $instance = \${ "$class\::_instance" };
                $$instance = $fh->tell() unless $$instance;
                $dataLoc = $$instance;
            }
        
            $fh->seek($dataLoc, 0);
            &readMagicHandle($self, $fh);
            $do_data_magic_only_once = $self->{magic};
        }
    } else {
	my $filename = shift;
	my $fh = new FileHandle;
	if ($fh->open("< $filename")) {
	    binmode($fh);
	    &readMagicHandle($self, $fh);
	} else {
	    warn __PACKAGE__ . " couldn't load specified file $filename";
	}
    }

# from the BSD names.h, some tokens for hard-coded checks of
# different texts.  This isn't rocket science.  It's prone to
# failure so these checks are only a last resort.

# removSpecials() can be used to remove those afterwards.
    $self->{SPECIALS} = {
		 "message/rfc822" => [ "^Received:",   
			     "^>From ",       
			     "^From ",       
			     "^To: ",
			     "^Return-Path: ",
			     "^Cc: ",
			     "^X-Mailer: "],
		 "message/news" => [ "^Newsgroups: ", 
			     "^Path: ",       
			     "^X-Newsreader: "],
		 "text/html" => [ "<html[^>]*>",
			     "<HTML[^>]*>",
			     "<head[^>]*>",
			     "<HEAD[^>]*>",
			     "<body[^>]*>",
			     "<BODY[^>]*>",
			     "<title[^>]*>",
			     "<TITLE[^>]*>",
			     "<h1[^>]*>",
			     "<H1[^>]*>",
			],
		 "text/x-roff" => [
			      '^\\.\\\\"',
			      "^\\.SH ",
			      "^\\.PP ",
			      "^\\.TH ",
			      "^\\.BR ",
			      "^\\.SS ",
			      "^\\.TP ",
			      "^\\.IR ",
				   ],
		};

    $self->{FILEEXTS} = {
	     '\.gz$' => 'application/x-gzip',
	     '\.bz2$' => 'application/x-bzip2',
	     '\.Z$' => 'application/x-compress',
	     '\.txt$' => 'text/plain',
	     '\.html$' => 'text/html',
	     '\.htm$' => 'text/html',
    };
    bless($self);
    return $self;
}