updating README, better exclusivity handling

Author: dctucker

README.md

@@ -1,6 +1,46 @@
 # midibus
 My implementation of a MIDI bus to connect multiple synths
 
+## Legacy implementation
+
 Uses `udev` rules to make ALSA sequencer connections when plugged in, updates the UI when changes are made.
 
-<img src="Matrix.png" />
+## Latest incarnation
+
+Still uses `udev` rules, but uses the ALSA RawMidi Interface to listen for
+incoming messages and relay them to output devices in a threaded server which
+handles SIGHUP when a new device is connected.
+
+### But why?
+
+- I want to get as close to parsing actual MIDI messages as possible
+without all the extra metadata attached to each event by ALSA.
+- This way I can implement my own filtering and custom macros.
+  - Relay realtime messages from the Deluge, send all realtime messages from the
+Electribe to `/dev/null`.
+  - Gracefully handle forwarding system exclusive messages so I can program my
+JUNO from the computer.
+
+## What does my setup look like?
+
+The concept of a "master keyboard" has stuck with me, and for this purpose I
+currently use the Roland JUNO-DS 88. Connected to my Raspberry Pi running this
+software, I have a Synthstrom Audible Deluge for
+sequencing and sound design, a Moog Little Phatty Stage II for warm analog synth
+sounds, a Novation Circuit for synth layering, a Korg Electribe Sampler for
+effects and drum layering, and finally an iConnectivity mio that acts as a
+bridge between my synth rig and my DAW computer.
+
+## Screenshot
+
+<img src="images/fbcat.png" />
+
+## Client/server
+
+Currently the client is extremely dumb, simply reading the server's config file.
+This will change in the future making it more interactive. But hey, at least it
+looks good, and you can see the current configuration presented visually.
+
+The server has a thread for each input device, and maintains state for each
+output device in shared memory.
+

Matrix.png images/Matrix.png

@@ -32,22 +32,31 @@ void configure_connection(const char *in_name, const char *out_name, char *func_
 
 void manage_inputs()
 {
-	int i = 0;
-	for(; i < n_read_threads; ++i )
+	int tries = 0;
+	int had_errors;
+	do
 	{
-		if( read_data[i].midi != NULL )
-			continue;
-		if( strlen(read_data[i].port_name) <= 0 )
-			continue;
-		int result, tries = 0;
-		while( (result = setup_midi_device( &read_data[i] ) ) != 0 && tries < 5 )
+		had_errors = 0;
+		int i = 0;
+		for(; i < n_read_threads; ++i )
 		{
-			tries++;
-			usleep(200*1000);
+			if( read_data[i].midi != NULL )
+				continue;
+			if( strlen(read_data[i].port_name) <= 0 )
+				continue;
+			int result;
+			result = setup_midi_device( &read_data[i] );
+			if( result == 0 && read_data[i].midi != NULL )
+				pthread_create( &threads[i], NULL, read_thread, (void *) &read_data[i] );
+			else
+				had_errors++;
 		}
-		if( result == 0 && read_data[i].midi != NULL )
-			pthread_create( &threads[i], NULL, read_thread, (void *) &read_data[i] );
+
+		if( had_errors )
+			usleep(400*1000);
+		tries++;
 	}
+	while( had_errors && tries < 5 );
 }
 
 void manage_outputs()

images/fbcat.png

@@ -0,0 +1,7 @@
+JUNO-DS switching to Performance mode, USER 01
+
+BF 00 55 BF 20 00 CF 00
+
+Ch16 CC 0  BANK MSB = 85
+Ch16 CC 32 BANK LSB = 0
+Ch16 PC = 00

server/main.c

@@ -127,14 +127,13 @@ void *read_thread(void *arg)
 			struct write_data *out = &data->outs[o];
 			if( out->output_device == NULL || out->output_device->midi == NULL || out->func == NULL )
 				continue;
-			if( out->output_device->midi_in_exclusive == data )
-			{
-				write_thru( out, buf, err, out->args );
-			}
-			else if( out->func( out, buf, err, out->args ) )
-			{
+			snd_rawmidi_t *excl = out->output_device->midi_in_exclusive;
+
+			if( excl != NULL && excl != data->midi )
+				continue;
+
+			if( out->func( out, buf, err, out->args ) )
 				printf("%s\n", out->port_name);
-			}
 		}
 		fflush(stdout);
 	}

server/midi-server

@@ -19,7 +19,7 @@ struct output_device_t {
 struct write_data
 {
 	struct output_device_t *output_device;
-	struct snd_rawmidi_t *midi_in;
+	snd_rawmidi_t *midi_in;
 	const char *port_name;
 	int (*func)();
 	void *args;

server/notes.txt

@@ -106,7 +106,7 @@ void setup_write_func( struct write_data *data, char *name, char *args )
 				else if( strcmp(pt, "rt") == 0 )
 					channel_mask |= MASK_RT;
 				else if( strcmp(pt, "all") == 0 )
-					channel_mask |= MASK_ALL_CHANNELS;
+					channel_mask |= MASK_ALL;
 			}
 			else
 				channel_mask |= 1 << a;