--- 3m-810.pl	2008/10/03 21:47:24	21
+++ 3m-810.pl	2008/10/04 11:55:30	22
@@ -30,7 +30,7 @@
 };
 
 GetOptions(
-	'd|debug+'      => \$debug,
+	'd|debug+'    => \$debug,
 	'device=s'    => \$device,
 	'baudrate=i'  => \$baudrate,
 	'databits=i'  => \$databits,
@@ -39,6 +39,8 @@
 	'handshake=s' => \$handshake,
 ) or die $!;
 
+my $verbose = $debug > 0 ? $debug-- : 0;
+
 =head1 NAME
 
 3m-810 - support for 3M 810 RFID reader
@@ -70,9 +72,6 @@
 
 =cut
 
-my $tags_data;
-my $visible_tags;
-
 my $port=new Device::SerialPort($device) || die "can't open serial port $device: $!\n";
 warn "using $device $handshake $baudrate $databits $parity $stopbits" if $debug;
 $handshake=$port->handshake($handshake);
@@ -81,7 +80,7 @@
 $parity=$port->parity($parity);
 $stopbits=$port->stopbits($stopbits);
 
-print "## using $device $baudrate $databits $parity $stopbits\n";
+print "## using $device $baudrate $databits $parity $stopbits debug: $debug verbose: $verbose\n";
 
 # Just in case: reset our timing and buffers
 $port->lookclear();
@@ -105,17 +104,13 @@
 # start scanning for tags
 
 cmd( 'D6 00  05   FE     00  05         FA40', "scan for tags, retry $_",
-     'D6 00  07   FE  00 00  05     00  C97B', sub {
-	 	assert();
-		print "no tag in range\n";
-
-	},
 	 'D6 00  0F   FE  00 00  05 ', sub { # 01 E00401003123AA26  941A	 # seen, serial length: 8
 		my $rest = shift || die "no rest?";
 		my $nr = ord( substr( $rest, 0, 1 ) );
 
 		if ( ! $nr ) {
 			print "no tags in range\n";
+			update_visible_tags();
 		} else {
 
 			my $tags = substr( $rest, 1 );
@@ -126,26 +121,50 @@
 			my @tags;
 			push @tags, uc(unpack('H16', substr($tags, $_ * 8, 8))) foreach ( 0 .. $nr - 1 );
 			warn "## tags ",as_hex($tags), " [$tl] = ",dump( $tags ) if $debug;
-			print "seen $nr tags: ", join(',', @tags ) , "\n";
-
-			my $removed_tags = $visible_tags;
-			$visible_tags = {};
+			print "$nr tags in range: ", join(',', @tags ) , "\n";
 
-			foreach my $tag ( @tags ) {
-				next if $visible_tags->{$tag}++;
-				read_tag( $tag );
-				if ( delete $removed_tags->{$tag} ) {
-					print "removed tag $tag\n";
-				}
-			}
+			update_visible_tags( @tags );
 
 		}
 	}
 ) foreach ( 1 .. 100 );
 
+
+
+my $tags_data;
+my $visible_tags;
+
+sub update_visible_tags {
+	my @tags = @_;
+
+	my $last_visible_tags = $visible_tags;
+	$visible_tags = {};
+
+	foreach my $tag ( @tags ) {
+		if ( ! defined $last_visible_tags->{$tag} ) {
+			read_tag( $tag );
+			$visible_tags->{$tag}++;
+		} else {
+			warn "## using cached data for $tag" if $debug;
+		}
+		delete $last_visible_tags->{$tag}; # leave just missing tags
+	}
+
+	foreach my $tag ( keys %$last_visible_tags ) {
+		print "removed tag $tag with data ",dump( delete $tags_data->{$tag} ),"\n";
+	}
+
+	warn "## update_visible_tags(",dump( @tags ),") = ",dump( $visible_tags )," removed: ",dump( $last_visible_tags ), " data: ",dump( $tags_data ) if $debug;
+}
+
+
 sub read_tag {
 	my ( $tag ) = @_;
 
+	confess "no tag?" unless $tag;
+
+	return if defined $tags_data->{$tag};
+
 	print "read_tag $tag\n";
 
 	cmd(
@@ -320,7 +339,7 @@
 	my $checksum = substr( $data, -2, 2 );
 	checksum( $header . $length . $payload , $checksum );
 
-	print "<< ",as_hex( $header ), " [$len] ", as_hex( $payload ), " | sum: ",as_hex($checksum),"\n";
+	print "<< ",as_hex( $header ), " [$len] ", as_hex( $payload ), " | sum: ",as_hex($checksum),"\n" if $verbose;
 
 	$assert->{len}      = $len;
 	$assert->{payload}  = $payload;
@@ -366,7 +385,7 @@
 	# fix checksum if needed
 	$bytes = checksum( substr( $bytes, 0, -2 ), substr( $bytes, -2, 2 ) );
 
-	warn ">> ", as_hex( $bytes ), "\t## $cmd_desc\n";
+	warn ">> ", as_hex( $bytes ), "\t## $cmd_desc\n" if $verbose;
 	$assert->{send} = $cmd;
 	writechunk( $bytes );