Publish winmidi backend

4 files changed, 673 insertions, 1 deletions

diff --git a/backends/Makefile b/backends/Makefile
index 5c5b677..293b434 100644
--- a/backends/Makefile
+++ b/backends/Makefile
@@ -1,6 +1,6 @@
 .PHONY: all clean full
 LINUX_BACKENDS = midi.so evdev.so
-WINDOWS_BACKENDS = artnet.dll osc.dll loopback.dll sacn.dll maweb.dll
+WINDOWS_BACKENDS = artnet.dll osc.dll loopback.dll sacn.dll maweb.dll winmidi.dll
 BACKENDS = artnet.so osc.so loopback.so sacn.so lua.so maweb.so
 OPTIONAL_BACKENDS = ola.so
 BACKEND_LIB = libmmbackend.o
@@ -38,6 +38,9 @@ maweb.dll: ADDITIONAL_OBJS += $(BACKEND_LIB)
 maweb.dll: LDLIBS += -lws2_32
 maweb.dll: CFLAGS += -DMAWEB_NO_LIBSSL
 
+winmidi.dll: ADDITIONAL_OBJS += $(BACKEND_LIB)
+winmidi.dll: LDLIBS += -lwinmm -lws2_32
+
 midi.so: LDLIBS = -lasound
 evdev.so: CFLAGS += $(shell pkg-config --cflags libevdev)
 evdev.so: LDLIBS = $(shell pkg-config --libs libevdev)
diff --git a/backends/winmidi.c b/backends/winmidi.c
new file mode 100644
index 0000000..dd8442b
--- /dev/null
+++ b/backends/winmidi.c
@@ -0,0 +1,567 @@
+#include <string.h>
+
+#include "libmmbackend.h"
+#include <mmsystem.h>
+
+#define DEBUG
+#include "winmidi.h"
+
+#define BACKEND_NAME "winmidi"
+
+static struct {
+	uint8_t list_devices;
+	int socket_pair[2];
+
+	CRITICAL_SECTION push_events;
+	volatile size_t events_alloc;
+	volatile size_t events_active;
+	volatile winmidi_event* event;
+} backend_config = {
+	.list_devices = 0,
+	.socket_pair = {-1, -1}
+};
+
+//TODO allow connect-device specification by index
+//TODO detect option
+
+int init(){
+	backend winmidi = {
+		.name = BACKEND_NAME,
+		.conf = winmidi_configure,
+		.create = winmidi_instance,
+		.conf_instance = winmidi_configure_instance,
+		.channel = winmidi_channel,
+		.handle = winmidi_set,
+		.process = winmidi_handle,
+		.start = winmidi_start,
+		.shutdown = winmidi_shutdown
+	};
+
+	if(sizeof(winmidi_channel_ident) != sizeof(uint64_t)){
+		fprintf(stderr, "winmidi channel identification union out of bounds\n");
+		return 1;
+	}
+
+	//register backend
+	if(mm_backend_register(winmidi)){
+		fprintf(stderr, "Failed to register winmidi backend\n");
+		return 1;
+	}
+
+	//initialize critical section
+	InitializeCriticalSectionAndSpinCount(&backend_config.push_events, 4000);
+	return 0;
+}
+
+static int winmidi_configure(char* option, char* value){
+	if(!strcmp(option, "list")){
+		backend_config.list_devices = 0;
+		if(!strcmp(value, "on")){
+			backend_config.list_devices = 1;
+		}
+		return 0;
+	}
+
+	fprintf(stderr, "Unknown winmidi backend option %s\n", option);
+	return 1;
+}
+
+static int winmidi_configure_instance(instance* inst, char* option, char* value){
+	winmidi_instance_data* data = (winmidi_instance_data*) inst->impl;
+	if(!strcmp(option, "read")){
+		if(data->read){
+			fprintf(stderr, "winmidi instance %s already connected to an input device\n", inst->name);
+			return 1;
+		}
+		data->read = strdup(value);
+		return 0;
+	}
+	if(!strcmp(option, "write")){
+		if(data->write){
+			fprintf(stderr, "winmidi instance %s already connected to an otput device\n", inst->name);
+			return 1;
+		}
+		data->write = strdup(value);
+		return 0;
+	}
+
+	fprintf(stderr, "Unknown winmidi instance option %s\n", option);
+	return 1;
+}
+
+static instance* winmidi_instance(){
+	instance* i = mm_instance();
+	if(!i){
+		return NULL;
+	}
+
+	i->impl = calloc(1, sizeof(winmidi_instance_data));
+	if(!i->impl){
+		fprintf(stderr, "Failed to allocate memory\n");
+		return NULL;
+	}
+
+	return i;
+}
+
+static channel* winmidi_channel(instance* inst, char* spec){
+	char* next_token = NULL;
+	winmidi_channel_ident ident = {
+		.label = 0
+	};
+
+	if(!strncmp(spec, "ch", 2)){
+		next_token = spec + 2;
+		if(!strncmp(spec, "channel", 7)){
+			next_token = spec + 7;
+		}
+	}
+	else{
+		fprintf(stderr, "Unknown winmidi channel specification %s\n", spec);
+		return NULL;
+	}
+
+	ident.fields.channel = strtoul(next_token, &next_token, 10);
+	if(ident.fields.channel > 15){
+		fprintf(stderr, "MIDI channel out of range in winmidi channel spec %s\n", spec);
+		return NULL;
+	}
+
+	if(*next_token != '.'){
+		fprintf(stderr, "winmidi channel specification %s does not conform to channel<X>.<control><Y>\n", spec);
+		return NULL;
+	}
+
+	next_token++;
+
+	if(!strncmp(next_token, "cc", 2)){
+		ident.fields.type = cc;
+		next_token += 2;
+	}
+	else if(!strncmp(next_token, "note", 4)){
+		ident.fields.type = note;
+		next_token += 4;
+	}
+	else if(!strncmp(next_token, "pressure", 8)){
+		ident.fields.type = pressure;
+		next_token += 8;
+	}
+	else if(!strncmp(next_token, "pitch", 5)){
+		ident.fields.type = pitchbend;
+	}
+	else if(!strncmp(next_token, "aftertouch", 10)){
+		ident.fields.type = aftertouch;
+	}
+	else{
+		fprintf(stderr, "Unknown winmidi channel control type in %s\n", spec);
+		return NULL;
+	}
+
+	ident.fields.control = strtoul(next_token, NULL, 10);
+
+	if(ident.label){
+		return mm_channel(inst, ident.label, 1);
+	}
+	return NULL;
+}
+
+static int winmidi_set(instance* inst, size_t num, channel** c, channel_value* v){
+	winmidi_instance_data* data = (winmidi_instance_data*) inst->impl;
+	winmidi_channel_ident ident = {
+		.label = 0
+	};
+	union {
+		struct {
+			uint8_t status;
+			uint8_t data1;
+			uint8_t data2;
+			uint8_t unused;
+		} components;
+		DWORD dword;
+	} output = {
+		.dword = 0
+	};
+	size_t u;
+
+	if(!data->device_out){
+		fprintf(stderr, "winmidi instance %s has no output device\n", inst->name);
+		return 0;
+	}
+
+	for(u = 0; u < num; u++){
+		ident.label = c[u]->ident;
+
+		switch(ident.fields.type){
+			case note:
+				output.components.status = 0x90 | ident.fields.channel;
+				output.components.data1 = ident.fields.control;
+				output.components.data2 = v[u].normalised * 127.0;
+				break;
+			case cc:
+				output.components.status = 0xB0 | ident.fields.channel;
+				output.components.data1 = ident.fields.control;
+				output.components.data2 = v[u].normalised * 127.0;
+				break;
+			case pressure:
+				output.components.status = 0xA0 | ident.fields.channel;
+				output.components.data1 = ident.fields.control;
+				output.components.data2 = v[u].normalised * 127.0;
+				break;
+			case aftertouch:
+				output.components.status = 0xD0 | ident.fields.channel;
+				output.components.data1 = v[u].normalised * 127.0;
+				output.components.data2 = 0;
+				break;
+			case pitchbend:
+				output.components.status = 0xE0 | ident.fields.channel;
+				output.components.data1 = ((int)(v[u].normalised * 32639.0)) & 0xFF;
+				output.components.data2 = (((int)(v[u].normalised * 32639.0)) & 0xFF00) >> 8;
+				break;
+			default:
+				fprintf(stderr, "Unknown winmidi channel type %d\n", ident.fields.type);
+				continue;
+		}
+
+		midiOutShortMsg(data->device_out, output.dword);
+	}
+	
+	return 0;
+}
+
+static int winmidi_handle(size_t num, managed_fd* fds){
+	size_t u;
+	ssize_t bytes = 0;
+	char recv_buf[1024];
+	channel* chan = NULL;
+	if(!num){
+		return 0;
+	}
+
+	//flush the feedback socket
+	for(u = 0; u < num; u++){
+		bytes += recv(fds[u].fd, recv_buf, sizeof(recv_buf), 0);
+	}
+
+	//push queued events
+	EnterCriticalSection(&backend_config.push_events);
+	for(u = 0; u < backend_config.events_active; u++){
+		chan = mm_channel(backend_config.event[u].inst, backend_config.event[u].channel.label, 0);
+		if(chan){
+			mm_channel_event(chan, backend_config.event[u].value);
+		}
+	}
+	DBGPF("winmidi flushed %" PRIsize_t " wakeups, handled %" PRIsize_t " events\n", bytes, backend_config.events_active);
+	backend_config.events_active = 0;
+	LeaveCriticalSection(&backend_config.push_events);
+	return 0;
+}
+
+static void CALLBACK winmidi_input_callback(HMIDIIN device, unsigned message, DWORD_PTR inst, DWORD param1, DWORD param2){
+	winmidi_channel_ident ident = {
+		.label = 0
+	};
+	channel_value val;
+	union {
+		struct {
+			uint8_t status;
+			uint8_t data1;
+			uint8_t data2;
+			uint8_t unused;
+		} components;
+		DWORD dword;
+	} input = {
+		.dword = 0
+	};
+
+	//callbacks may run on different threads, so we queue all events and alert the main thread via the feedback socket
+	DBGPF("winmidi input callback on thread %ld\n", GetCurrentThreadId());
+
+	switch(message){
+		case MIM_MOREDATA:
+			//processing too slow, do not immediately alert the main loop
+		case MIM_DATA:
+			//param1 has the message
+			input.dword = param1;
+			ident.fields.channel = input.components.status & 0x0F;
+			switch(input.components.status & 0xF0){
+				case 0x80:
+					ident.fields.type = note;
+					ident.fields.control = input.components.data1;
+					val.normalised = 0.0;
+					break;
+				case 0x90:
+					ident.fields.type = note;
+					ident.fields.control = input.components.data1;
+					val.normalised = (double) input.components.data2 / 127.0;
+					break;
+				case 0xA0:
+					ident.fields.type = pressure;
+					ident.fields.control = input.components.data1;
+					val.normalised = (double) input.components.data2 / 127.0;
+					break;
+				case 0xB0:
+					ident.fields.type = cc;
+					ident.fields.control = input.components.data1;
+					val.normalised = (double) input.components.data2 / 127.0;
+					break;
+				case 0xD0:
+					ident.fields.type = aftertouch;
+					ident.fields.control = 0;
+					val.normalised = (double) input.components.data1 / 127.0;
+					break;
+				case 0xE0:
+					ident.fields.type = pitchbend;
+					ident.fields.control = 0;
+					val.normalised = (double)((input.components.data2 << 8) | input.components.data1) / 32639.0;
+					break;
+				default:
+					fprintf(stderr, "winmidi unhandled status byte %02X\n", input.components.status);
+					return;
+			}
+			break;
+		case MIM_LONGDATA:
+			//sysex message, ignore
+			return;
+		case MIM_ERROR:
+			//error in input stream
+			fprintf(stderr, "winmidi warning: error in input stream\n");
+			return;
+		case MIM_OPEN:
+		case MIM_CLOSE:
+			//device opened/closed
+			return;
+		
+	}
+
+	DBGPF("winmidi incoming message type %d channel %d control %d value %f\n",
+			ident.fields.type, ident.fields.channel, ident.fields.control, val.normalised);
+
+	EnterCriticalSection(&backend_config.push_events);
+	if(backend_config.events_alloc <= backend_config.events_active){
+		backend_config.event = realloc((void*) backend_config.event, (backend_config.events_alloc + 1) * sizeof(winmidi_event));
+		if(!backend_config.event){
+			fprintf(stderr, "Failed to allocate memory\n");
+			backend_config.events_alloc = 0;
+			backend_config.events_active = 0;
+			LeaveCriticalSection(&backend_config.push_events);
+			return;
+		}
+		backend_config.events_alloc++;
+	}
+	backend_config.event[backend_config.events_active].inst = (instance*) inst;
+	backend_config.event[backend_config.events_active].channel.label = ident.label;
+	backend_config.event[backend_config.events_active].value = val;
+	backend_config.events_active++;
+	LeaveCriticalSection(&backend_config.push_events);
+
+	if(message != MIM_MOREDATA){
+		//alert the main loop
+		send(backend_config.socket_pair[1], "w", 1, 0);
+	}
+}
+
+static void CALLBACK winmidi_output_callback(HMIDIOUT device, unsigned message, DWORD_PTR inst, DWORD param1, DWORD param2){
+	DBGPF("winmidi output callback on thread %ld\n", GetCurrentThreadId());
+}
+
+static int winmidi_match_input(char* prefix){
+	MIDIINCAPS input_caps;
+	unsigned inputs = midiInGetNumDevs();
+	char* next_token = NULL;
+	size_t n;
+
+	if(!prefix){
+		fprintf(stderr, "winmidi detected %u input devices\n", inputs);
+	}
+	else{
+		n = strtoul(prefix, &next_token, 10);
+		if(!(*next_token) && n < inputs){
+			midiInGetDevCaps(n, &input_caps, sizeof(MIDIINCAPS));
+			fprintf(stderr, "winmidi selected input device %s for ID %d\n", input_caps.szPname, n);
+			return n;
+		}
+	}
+
+	//find prefix match for input device
+	for(n = 0; n < inputs; n++){
+		midiInGetDevCaps(n, &input_caps, sizeof(MIDIINCAPS));
+		if(!prefix){
+			printf("\tID %d: %s\n", n, input_caps.szPname);
+		}
+		else if(!strncmp(input_caps.szPname, prefix, strlen(prefix))){
+			fprintf(stderr, "winmidi selected input device %s for name %s\n", input_caps.szPname, prefix);
+			return n;
+		}
+	}
+
+	return -1;
+}
+
+static int winmidi_match_output(char* prefix){
+	MIDIOUTCAPS output_caps;
+	unsigned outputs = midiOutGetNumDevs();
+	char* next_token = NULL;
+	size_t n;
+
+	if(!prefix){
+		fprintf(stderr, "winmidi detected %u output devices\n", outputs);
+	}
+	else{
+		n = strtoul(prefix, &next_token, 10);
+		if(!(*next_token) && n < outputs){
+			midiOutGetDevCaps(n, &output_caps, sizeof(MIDIOUTCAPS));
+			fprintf(stderr, "winmidi selected output device %s for ID %d\n", output_caps.szPname, n);
+			return n;
+		}
+	}
+
+	//find prefix match for output device
+	for(n = 0; n < outputs; n++){
+		midiOutGetDevCaps(n, &output_caps, sizeof(MIDIOUTCAPS));
+		if(!prefix){
+			printf("\tID %d: %s\n", n, output_caps.szPname);
+		}
+		else if(!strncmp(output_caps.szPname, prefix, strlen(prefix))){
+			fprintf(stderr, "winmidi selected output device %s for name %s\n", output_caps.szPname, prefix);
+			return n;
+		}
+	}
+
+	return -1;
+}
+
+static int winmidi_start(){
+	size_t n = 0, p;
+	int device, rv = -1;
+	instance** inst = NULL;
+	winmidi_instance_data* data = NULL;
+	struct sockaddr_storage sockadd;
+	//this really should be a size_t but getsockname specifies int* for some reason
+	int sockadd_len = sizeof(sockadd);
+	DBGPF("winmidi main thread ID is %ld\n", GetCurrentThreadId());
+
+	//fetch all instances
+	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
+		fprintf(stderr, "Failed to fetch instance list\n");
+		return 1;
+	}
+
+	//no instances, we're done
+	if(!n){
+		free(inst);
+		return 0;
+	}
+
+	//output device list if requested
+	if(backend_config.list_devices){
+		winmidi_match_input(NULL);
+		winmidi_match_output(NULL);
+	}
+
+	//open the feedback sockets
+	backend_config.socket_pair[0] = mmbackend_socket(NULL, "0", SOCK_DGRAM, 1, 0);
+	if(backend_config.socket_pair[0] < 0){
+		fprintf(stderr, "winmidi failed to open feedback socket\n");
+		return 1;
+	}
+	if(getsockname(backend_config.socket_pair[0], (struct sockaddr*) &sockadd, &sockadd_len)){
+		fprintf(stderr, "winmidi failed to query feedback socket information\n");
+		return 1;
+	}
+	backend_config.socket_pair[1] = socket(sockadd.ss_family, SOCK_DGRAM, IPPROTO_UDP);
+	if(backend_config.socket_pair[1] < 0 || connect(backend_config.socket_pair[1], (struct sockaddr*) &sockadd, sockadd_len)){
+		fprintf(stderr, "winmidi failed to connect to feedback socket\n");
+		return 1;
+	}
+
+	//set up instances and start input
+	for(p = 0; p < n; p++){
+		data = (winmidi_instance_data*) inst[p]->impl;
+		inst[p]->ident = p;
+
+		//connect input device if requested
+		if(data->read){
+			device = winmidi_match_input(data->read);
+			if(device < 0){
+				fprintf(stderr, "Failed to match input device %s for instance %s\n", data->read, inst[p]->name);
+				goto bail;
+			}
+			if(midiInOpen(&(data->device_in), device, (DWORD_PTR) winmidi_input_callback, (DWORD_PTR) inst[p], CALLBACK_FUNCTION | MIDI_IO_STATUS) != MMSYSERR_NOERROR){
+				fprintf(stderr, "Failed to open input device for instance %s\n", inst[p]->name);
+				goto bail;
+			}
+			//start midi input callbacks
+			midiInStart(data->device_in);
+		}
+
+		//connect output device if requested
+		if(data->write){
+			device = winmidi_match_output(data->write);
+			if(device < 0){
+				fprintf(stderr, "Failed to match output device %s for instance %s\n", data->read, inst[p]->name);
+				goto bail;
+			}
+			if(midiOutOpen(&(data->device_out), device, (DWORD_PTR) winmidi_output_callback, (DWORD_PTR) inst[p], CALLBACK_FUNCTION) != MMSYSERR_NOERROR){
+				fprintf(stderr, "Failed to open output device for instance %s\n", inst[p]->name);
+				goto bail;
+			}
+		}
+	}
+
+	//register the feedback socket to the core
+	fprintf(stderr, "winmidi backend registering 1 descriptor to core\n");
+	if(mm_manage_fd(backend_config.socket_pair[0], BACKEND_NAME, 1, NULL)){
+		goto bail;
+	}
+
+	rv = 0;
+bail:
+	free(inst);
+	return rv;
+}
+
+static int winmidi_shutdown(){
+	size_t n, u;
+	instance** inst = NULL;
+	winmidi_instance_data* data = NULL;
+
+	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
+		fprintf(stderr, "Failed to fetch instance list\n");
+		return 1;
+	}
+
+	for(u = 0; u < n; u++){
+		data = (winmidi_instance_data*) inst[u]->impl;
+		free(data->read);
+		data->read = NULL;
+		free(data->write);
+		data->write = NULL;
+
+		if(data->device_in){
+			midiInStop(data->device_in);
+			midiInClose(data->device_in);
+			data->device_in = NULL;
+		}
+
+		if(data->device_out){
+			midiOutReset(data->device_out);
+			midiOutClose(data->device_out);
+			data->device_out = NULL;
+		}
+	}
+
+	free(inst);
+	closesocket(backend_config.socket_pair[0]);
+	closesocket(backend_config.socket_pair[1]);
+
+	EnterCriticalSection(&backend_config.push_events);
+	free((void*) backend_config.event);
+	backend_config.event = NULL;
+	backend_config.events_alloc = 0;
+	backend_config.events_active = 0;
+	LeaveCriticalSection(&backend_config.push_events);
+	DeleteCriticalSection(&backend_config.push_events);
+
+	fprintf(stderr, "winmidi backend shut down\n");
+	return 0;
+}
diff --git a/backends/winmidi.h b/backends/winmidi.h
new file mode 100644
index 0000000..e4abda1
--- /dev/null
+++ b/backends/winmidi.h
@@ -0,0 +1,43 @@
+#include "midimonster.h"
+
+int init();
+static int winmidi_configure(char* option, char* value);
+static int winmidi_configure_instance(instance* inst, char* option, char* value);
+static instance* winmidi_instance();
+static channel* winmidi_channel(instance* inst, char* spec);
+static int winmidi_set(instance* inst, size_t num, channel** c, channel_value* v);
+static int winmidi_handle(size_t num, managed_fd* fds);
+static int winmidi_start();
+static int winmidi_shutdown();
+
+typedef struct /*_winmidi_instance_data*/ {
+	char* read;
+	char* write;
+	HMIDIIN device_in;
+	HMIDIOUT device_out;
+} winmidi_instance_data;
+
+enum /*_winmidi_channel_type*/ {
+	none = 0,
+	note,
+	cc,
+	pressure,
+	aftertouch,
+	pitchbend
+};
+
+typedef union {
+	struct {
+		uint8_t pad[5];
+		uint8_t type;
+		uint8_t channel;
+		uint8_t control;
+	} fields;
+	uint64_t label;
+} winmidi_channel_ident;
+
+typedef struct /*_winmidi_event_queue_entry*/ {
+	instance* inst;
+	winmidi_channel_ident channel;
+	channel_value value;
+} winmidi_event;
diff --git a/backends/winmidi.md b/backends/winmidi.md
new file mode 100644
index 0000000..b1fde1e
--- /dev/null
+++ b/backends/winmidi.md
@@ -0,0 +1,59 @@
+### The `winmidi` backend
+
+This backend provides read-write access to the MIDI protocol via the Windows Multimedia API.
+
+It is only available when building for Windows. Care has been taken to keep the configuration
+syntax similar to the `midi` backend, but due to differences in the internal programming interfaces,
+some deviations may still be present.
+
+#### Global configuration
+
+| Option	| Example value		| Default value 	| Description		|
+|---------------|-----------------------|-----------------------|-----------------------|
+| `list`	| `on`                  | `off`                 | List available input/output devices on startup |
+| `detect`      | `on`                  | `off`                 | Output channel specifications for any events coming in on configured instances to help with configuration. |
+
+#### Instance configuration
+
+| Option	| Example value		| Default value 	| Description		|
+|---------------|-----------------------|-----------------------|-----------------------|
+| `read`	| `2`			| none			| MIDI device to connect for input |
+| `write`	| `DeviceName`		| none			| MIDI device to connect for output |
+
+MIDI device names may either be prefixes of MIDI device names or a numeric index corresponding to the list output at startup using the backend `list` option.
+
+#### Channel specification
+
+The MIDI backend supports mapping different MIDI events to MIDIMonster channels. The currently supported event types are
+
+* `cc` - Control Changes
+* `note` - Note On/Off messages
+* `pressure` - Note pressure/aftertouch messages
+* `aftertouch` - Channel-wide aftertouch messages
+* `pitch` - Channel pitchbend messages
+
+A MIDIMonster channel is specified using the syntax `channel<channel>.<type><index>`. The shorthand `ch` may be
+used instead of the word `channel` (Note that `channel` here refers to the MIDI channel number).
+
+The `pitch` and `aftertouch` events are channel-wide, thus they can be specified as `channel<channel>.<type>`.
+
+MIDI channels range from `0` to `15`. Each MIDI channel consists of 128 notes (numbered `0` through `127`), which
+additionally each have a pressure control, 128 CC's (numbered likewise), a channel pressure control (also called
+'channel aftertouch') and a pitch control which may all be mapped to individual MIDIMonster channels.
+
+Example mappings:
+```
+midi1.ch0.note9 > midi2.channel1.cc4
+midi1.channel15.pressure1 > midi1.channel0.note0
+midi1.ch1.aftertouch > midi2.ch2.cc0
+midi1.ch0.pitch > midi2.ch1.pitch
+```
+
+#### Known bugs / problems
+
+Currently, no Note Off messages are sent (instead, Note On messages with a velocity of 0 are
+generated, which amount to the same thing according to the spec). This may be implemented as
+a configuration option at a later time.
+
+As this is a Windows-only backend, testing may not be as frequent or thorough as for the Linux / multiplatform
+backends.