spiralsynthmodular/SpiralSound/Midi.C

/*
 *  Copyleft (C) 2000 David Griffiths <dave@pawfal.org>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/

#include "Midi.h"
#include "unistd.h"
#include "sys/types.h"
#include "signal.h"
#include "pthread.h"

static const int MIDI_SCANBUFSIZE=256;
static const int MIDI_KEYOFFSET=0;

static const unsigned char STATUS_START            = 0x80;
static const unsigned char STATUS_NOTE_OFF         = 0x80;
static const unsigned char STATUS_NOTE_ON          = 0x90;
static const unsigned char STATUS_AFTERTOUCH       = 0xa0;
static const unsigned char STATUS_CONTROL_CHANGE   = 0xb0;
static const unsigned char STATUS_PROG_CHANGE      = 0xc0;
static const unsigned char STATUS_CHANNEL_PRESSURE = 0xd0;
static const unsigned char STATUS_PITCH_WHEEL      = 0xe0;
static const unsigned char STATUS_END              = 0xf0;
static const unsigned char SYSEX_START             = 0xf0;
static const unsigned char SYSEX_TERMINATOR        = 0xf7;
static const unsigned char MIDI_CLOCK              = 0xf8;
static const unsigned char ACTIVE_SENSE            = 0xfe;

static int NKEYS = 30;

MidiDevice *MidiDevice::m_Singleton;
string MidiDevice::m_AppName;

#if __APPLE__
#define read	AppleRead
#endif

#ifdef USE_OSS_MIDI
string MidiDevice::m_DeviceName;
#endif

void MidiDevice::Init(const string &name, Type t)
{
	if (!m_Singleton)
	{
		m_AppName=name;
		m_Singleton=new MidiDevice(t);
	}
}

MidiDevice::MidiDevice(Type t) :
m_Poly (1),
m_Clock (1.0f),
m_ClockCount (0)
{
#if __APPLE__
     AppleOpen();
#endif
#ifdef USE_ALSA_MIDI
     AlsaOpen();
#endif
#ifdef USE_OSS_MIDI
     if (!OssOpen()) return;
#endif
     m_Mutex = new pthread_mutex_t;
     pthread_mutex_init (m_Mutex, NULL);
     pthread_create (&m_MidiReader, NULL, (void*(*)(void*))MidiDevice::MidiReaderCallback, (void*)this);
}

MidiDevice::~MidiDevice() {
     pthread_mutex_lock (m_Mutex);
     pthread_cancel (m_MidiReader);
     pthread_mutex_unlock (m_Mutex);
     pthread_mutex_destroy (m_Mutex);
#if __APPLE__
     AppleClose();
#endif
#ifdef USE_ALSA_MIDI
     AlsaClose();
#endif
#ifdef USE_OSS_MIDI
     OssClose();
#endif
}

// returns the next event off the list, or an
// empty event if the list is exhausted
MidiEvent MidiDevice::GetEvent(int Device)
{
	if (Device<0 || Device>15)
	{
		cerr<<"GetEvent: Invalid Midi device "<<Device<<endl;
		return MidiEvent(MidiEvent::NONE,0,0);
	}

	pthread_mutex_lock(m_Mutex);
	if (m_EventVec[Device].size()==0)
	{
		pthread_mutex_unlock(m_Mutex);
		return MidiEvent(MidiEvent::NONE,0,0);
	}

	MidiEvent event(m_EventVec[Device].front());
	m_EventVec[Device].pop();
	pthread_mutex_unlock(m_Mutex);

	return event;
}

void MidiDevice::SendEvent (int Device, const MidiEvent &Event) {
#ifdef USE_ALSA_MIDI
	AlsaSendEvent (Device, Event);
#else
	if (Device<0 || Device>15)
	{
		cerr<<"SendEvent: Invalid Midi device "<<Device<<endl;
	}

	char message[3];

	message[1]=Event.GetNote()+MIDI_KEYOFFSET;
	message[2]=(char)Event.GetVolume();

	if (Event.GetType()==MidiEvent::ON)
	{
		message[0]=STATUS_NOTE_ON+Device;
		write(m_MidiWrFd,message,3);
		//cerr<<"sending "<<message<<endl;
	}

	if (Event.GetType()==MidiEvent::OFF)
	{
		message[0]=STATUS_NOTE_OFF+Device;
		write(m_MidiWrFd,message,3);
		//cerr<<"sending "<<message<<endl;
	}
#endif
}

//////////////////////////////////////////// Oss Code Only ////////////////////////////////////////

#ifdef USE_OSS_MIDI

bool MidiDevice::OssOpen() {
     //if (!SpiralInfo::WANTMIDI) return;
     m_MidiFd = open (m_DeviceName.c_str(), O_RDONLY | O_SYNC);
     if (!m_MidiFd) {
        cerr << "Couldn't open midi for reading [" << m_DeviceName << "]" << endl;
        return false;
     }
     m_MidiWrFd = open (m_DeviceName.c_str(), O_WRONLY);
     if (!m_MidiWrFd) {
        cerr << "Couldn't open midi for writing [" << m_DeviceName << "]" << endl;
        return false;
     }
     cerr << "Opened midi device [" << m_DeviceName << "]" << endl;
     return true;
}

void MidiDevice::OssClose() {
     close(m_MidiFd);
     close(m_MidiWrFd);
     cerr<<"Closed midi device"<<endl;
}

// little helper to strip out the realtime and unused messages
void MidiDevice::OssReadByte(unsigned char *c)
{
	*c=ACTIVE_SENSE;
	do read(m_MidiFd,c,1);
	while (*c>=STATUS_END && *c!=MIDI_CLOCK);
}

// collect events deals with the byte level messages, and sorts
// and filters them into distinct messages we can handle easily

void MidiDevice::OssCollectEvents()
{
	unsigned char buf[1];
	int count,n,nn;
	bool MessageSent;
	unsigned char data[3],last=0;

	// constantly scan for relevent input,
	// and write it to the pipe

	// filters out unhandled messages, and attempts to build
	// coherent messages to send to the midi handler
	bool InSysex=false;

	for(;;)
	{
		OssReadByte(buf);

		if (*buf==MIDI_CLOCK)
		{
			m_ClockCount++;
			if (m_ClockCount==6)
			{
				m_Clock=-m_Clock;
				m_ClockCount=0;
			}
		}
		else
		if (*buf>=STATUS_START) // we've got a status byte
		{
			if (*buf==SYSEX_TERMINATOR) InSysex=false;

			// find out if it's an opcode
			if(*buf>=STATUS_START && *buf<=STATUS_END)
			{
				InSysex=false;
				last=data[0]=*buf;

				if (data[0]>=STATUS_PROG_CHANGE && data[0]<STATUS_PITCH_WHEEL)
				{
					OssReadByte(&data[1]); //one byte
					data[2]=0;
				}
				else // get the next two bytes
				{
					OssReadByte(&data[1]);
					OssReadByte(&data[2]);
				}
				OssAddEvent(data);
			}
			else // its a sysex or other message like active sense
			{
				if (*buf==SYSEX_START) InSysex=true;
				cerr<<"Unhandled midi message: "; printf("%x\n",(int)*buf);
			}
		}
		else // more data (running status)
		{
			if (!InSysex)
			{
				data[0]=last;
				data[1]=*buf;

				if (data[0]>=STATUS_PROG_CHANGE && data[0]<STATUS_PITCH_WHEEL)
				{
					data[2]=0;  //one byte
				}
				else // get the next byte
				{
					OssReadByte(&data[2]);
				}

				OssAddEvent(data);
			}
		}
	}
}

// addevent converts the midi bytecode into midi message objects and
// stacks them onto the event list to be picked up by the app
void MidiDevice::OssAddEvent(unsigned char* midi)
{
	MidiEvent::type MessageType=MidiEvent::NONE;
	int Volume=0,Note=0,EventDevice=0;

	// note off
	if (midi[0] >= STATUS_NOTE_OFF && midi[0] < STATUS_NOTE_ON)
	{
		MessageType=MidiEvent::OFF;
		Note=midi[1]-MIDI_KEYOFFSET;
		EventDevice=midi[0]-STATUS_NOTE_OFF;
	}
	// note on
	else if (midi[0] >= STATUS_NOTE_ON && midi[0] < STATUS_AFTERTOUCH)
	{
		Volume = midi[2];

		// cope with Roland equipment, where note on's
		// with zero velocity are sent as note offs.
		if (Volume) MessageType=MidiEvent::ON;
		else MessageType=MidiEvent::OFF;

		Note=midi[1]-MIDI_KEYOFFSET;
		EventDevice=midi[0]-STATUS_NOTE_ON;
	}
	// aftertouch
	else if (midi[0] >= STATUS_AFTERTOUCH && midi[0] < STATUS_CONTROL_CHANGE)
	{
		MessageType=MidiEvent::AFTERTOUCH;
		Note=midi[1]-MIDI_KEYOFFSET;
		Volume=midi[2];
		EventDevice=midi[0]-STATUS_AFTERTOUCH;
	}
	// parameter
	else if (midi[0] >= STATUS_CONTROL_CHANGE && midi[0] < STATUS_PROG_CHANGE)
	{
		MessageType=MidiEvent::PARAMETER;
		Note=midi[1];
		Volume=midi[2];
		EventDevice=midi[0]-STATUS_CONTROL_CHANGE;
	}
	// channel pressure
	else if (midi[0] >= STATUS_CHANNEL_PRESSURE && midi[0] < STATUS_PITCH_WHEEL)
	{
		MessageType=MidiEvent::CHANNELPRESSURE;
		Volume=midi[1];
		EventDevice=midi[0]-STATUS_CHANNEL_PRESSURE;
	}
	// note pitchbend
	else if (midi[0] >= STATUS_PITCH_WHEEL && midi[0] < STATUS_END)
	{
		MessageType=MidiEvent::PITCHBEND;
		// should probably take the first byte into account too?
		Volume=midi[2];
		EventDevice=midi[0]-STATUS_PITCH_WHEEL;
	}

	if (EventDevice<0 || EventDevice>15)
	{
		cerr<<"Error - Midi device "<<EventDevice<<" ??"<<endl;
		return;
	}

	pthread_mutex_lock(m_Mutex);
	m_EventVec[EventDevice].push(MidiEvent(MessageType,Note,Volume));
	pthread_mutex_unlock(m_Mutex);
}

#endif

//////////////////////////////////////////// Alsa Code Only ////////////////////////////////////////

#ifdef USE_ALSA_MIDI

// code taken and modified from jack_miniFMsynth

void MidiDevice::AlsaClose () {

	//Alsa requires two handles - one for read and one for write, 
	//so we make sure too close both here
	
	snd_seq_close (seq_rhandle);
	snd_seq_close (seq_whandle);
}

void MidiDevice::AlsaCollectEvents () {
     //As Alsa only supports a read or write, we use the read handle here to poll our input
     //for MIDI events
	
     int seq_nfds, l1;
     struct pollfd *pfds;

     //get descriptors count to find out how many events are 
     //waiting to be processed
     seq_nfds = snd_seq_poll_descriptors_count(seq_rhandle, POLLIN);
     
     //poll the descriptors to be proccessed and loop through them
     pfds = new struct pollfd[seq_nfds];
     snd_seq_poll_descriptors(seq_rhandle, pfds, seq_nfds, POLLIN);
     for (;;) {
         if (poll (pfds, seq_nfds, 1000) > 0) {
            for (l1 = 0; l1 < seq_nfds; l1++) {
                if (pfds[l1].revents > 0) {
                   snd_seq_event_t *ev;
                   // this line looks suspect to me (Andy Preston)
                   // int l1;
                   MidiEvent::type MessageType=MidiEvent::NONE;
                   int Volume=0, Note=0, EventDevice=0;
                   do {
                      snd_seq_event_input (seq_rhandle, &ev);
                      if ((ev->type == SND_SEQ_EVENT_NOTEON) && (ev->data.note.velocity == 0)) {
                         ev->type = SND_SEQ_EVENT_NOTEOFF;
                      }
                      switch (ev->type) {
                        case SND_SEQ_EVENT_PITCHBEND:
                             // Andy Preston
                             MessageType=MidiEvent::PITCHBEND;
                             Volume = (char)((ev->data.control.value / 8192.0)*256);
                             break;
                        case SND_SEQ_EVENT_CONTROLLER:
                             MessageType=MidiEvent::PARAMETER;
                             Note = ev->data.control.param;
                             Volume = ev->data.control.value;
                             break;
                        case SND_SEQ_EVENT_NOTEON:
                             MessageType=MidiEvent::ON;
                             EventDevice = ev->data.control.channel;
                             Note = ev->data.note.note;
                             Volume = ev->data.note.velocity;
                             break;
                        case SND_SEQ_EVENT_NOTEOFF:
                             MessageType=MidiEvent::ON;
                             EventDevice = ev->data.control.channel;
                             Note = ev->data.note.note;
                             break;
                      }
                      pthread_mutex_lock (m_Mutex);
                      m_EventVec[EventDevice].push (MidiEvent (MessageType, Note, Volume));
                      pthread_mutex_unlock (m_Mutex);
                      snd_seq_free_event (ev);
                   } while (snd_seq_event_input_pending(seq_rhandle, 0) > 0);
                }
            }
         }
     }
     delete [] pfds;
}

void MidiDevice::AlsaSendEvent (int Device, const MidiEvent &Event) {
	//As Alsa only supports a read or write, we use the write handle here to send
	//our MIDI events

	snd_seq_event_t ev;
	
	snd_seq_ev_clear      (&ev);
  	snd_seq_ev_set_direct (&ev);
	snd_seq_ev_set_subs   (&ev);
	snd_seq_ev_set_source (&ev, 0);

	switch (Event.GetType())
	{
		case MidiEvent::ON:
                     ev.type = SND_SEQ_EVENT_NOTEON;
                     break;
		case MidiEvent::OFF:
                     ev.type = SND_SEQ_EVENT_NOTEOFF;
                     break;
/*		case MidiEvent::PARAMETER:
                     ev.type = SND_SEQ_EVENT_CONTROLLER;
                     ev.data.control.param = Event.GetNote();
                     ev.data.control.value = 
                     break;
		case MidiEvent::PITCHBEND:
                     ev.type = SND_SEQ_EVENT_PITCHBEND;
                     ev.data.control.param = Event.GetNote();
                     ev.data.control.value = 
                     break;*/
                default:
                     break;
	}

	ev.data.note.velocity = (char)Event.GetVolume()*127;
	ev.data.control.channel = Device;
	ev.data.note.note=Event.GetNote();

	snd_seq_event_output(seq_whandle, &ev);
	snd_seq_drain_output(seq_whandle);
}

void MidiDevice::AlsaOpen()
{
	int client_id, port_id;
	
	//Alsa apears to require two handles, one for read and one for write
	//so we try to open one first for input and then one for output
	
	//open input handle
	if (snd_seq_open(&seq_rhandle, "default", SND_SEQ_OPEN_INPUT, 0) < 0)
	{
		fprintf(stderr, "Error opening ALSA input sequencer.\n");
		exit(1);
	}

	//setup our input name as seen by other apps, and get corresponding client id
	snd_seq_set_client_name(seq_rhandle, m_AppName.c_str());
	client_id = snd_seq_client_id(seq_rhandle);

	//try and create our actual input port capable of being written to by MIDI outputs
	if ((port_id = snd_seq_create_simple_port(seq_rhandle, m_AppName.c_str(),
		SND_SEQ_PORT_CAP_WRITE|SND_SEQ_PORT_CAP_SUBS_WRITE,
		SND_SEQ_PORT_TYPE_APPLICATION) < 0)) 
	{
		fprintf(stderr, "Error creating input sequencer port.\n");
	}

	//open output handle
	if (snd_seq_open(&seq_whandle, "default", SND_SEQ_OPEN_OUTPUT, 0) < 0) 
	{
		fprintf(stderr, "Error opening ALSA ouput sequencer.\n");
		exit(1);
	}

	//setup our output name as seen by other apps, and get corresponding client id
	snd_seq_set_client_name(seq_whandle, m_AppName.c_str());
	client_id = snd_seq_client_id(seq_whandle);

	//try and create our actual output port capable of being read from by MIDI inputs
	if ((port_id = snd_seq_create_simple_port(seq_whandle, m_AppName.c_str(),
		SND_SEQ_PORT_CAP_READ|SND_SEQ_PORT_CAP_SUBS_READ,
		SND_SEQ_PORT_TYPE_APPLICATION) < 0)) 
	{
		fprintf(stderr, "Error creating output sequencer port.\n");
	}
}

#endif

////////////////////////////////////////////  Apple Code Only /////////////////////////////////////////

#if __APPLE__

void MidiDevice::AppleOpen()
{
	m_ReadFillIndex = m_ReadReadIndex = 0;

	OSStatus err = 0;

	mMIDISource					= NULL;
	mMIDIClient					= NULL;
	mMIDIDestination			= NULL;

	err = MIDIClientCreate(CFSTR("org.pawpal.ssm"), NULL, NULL, &mMIDIClient);
	if (err) printf("MIDIClientCreate failed returned %d\n", err);

	if (!err) {
		err = MIDISourceCreate(mMIDIClient, CFSTR("SpiralSynth"), &mMIDISource);
		if (err) printf("MIDIInputPortCreate failed returned %d\n", err);
	}

	if (!err) {
		err = MIDIDestinationCreate(mMIDIClient, CFSTR("SpiralSynth"), sMIDIRead, this, &mMIDIDestination);
		MIDIObjectSetIntegerProperty(mMIDIDestination, kMIDIPropertyUniqueID, 'SSmP');
	}
}


void MidiDevice::AppleClose()
{
	if (mMIDIDestination)
		MIDIEndpointDispose(mMIDIDestination);
	if (mMIDISource)
		MIDIEndpointDispose(mMIDISource);
	mMIDISource = NULL;
	if (mMIDIClient)
		MIDIClientDispose(mMIDIClient);
	mMIDIClient = NULL;
}

int MidiDevice::AppleWrite(int dummy, unsigned char *outbuffer, int maxlen)
{
	return 0;
}

int MidiDevice::AppleRead(int dummy, unsigned char *outbuffer, int maxlen)
{
	if (!mMIDIClient)
		return -1;
	int len = 0;
	do {
		while (m_ReadReadIndex == m_ReadFillIndex)
			usleep(1000);	// 1ms
		int readl =  m_ReadFillIndex - m_ReadReadIndex;
		if (readl < 0)
			readl += midi_ReadSize;	// wrapped
		while (len < maxlen && readl-- > 0) {
			int r = m_ReadReadIndex;
			outbuffer[len++] = m_ReadBuffer[r];
			r++;
			m_ReadReadIndex = r % midi_ReadSize;
		}
	} while (len < maxlen);
	return len;
}

void MidiDevice::sMIDIRead(const MIDIPacketList *pktlist, void *readProcRefCon, void *srcConnRefCon)
{
	MidiDevice & t = *((MidiDevice*)readProcRefCon);

	const MIDIPacket *packet = &pktlist->packet[0];
	for (int i = 0; i < (int)pktlist->numPackets; i++) {
		const MIDIPacket & p = *packet;

		for (int b = 0; b < p.length; b++) {
		//	printf("%02x ", p.data[b]);
			int d = t.m_ReadFillIndex;
			t.m_ReadBuffer[d] = p.data[b];
			d++;
			t.m_ReadFillIndex = d % midi_ReadSize;
		}
	//	printf("\n");
		packet = MIDIPacketNext(packet);
	}
}

#endif