/*====================================================================
 *
 * Copyright 1993, Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This is UNPUBLISHED PROPRIETARY SOURCE CODE of Silicon Graphics,
 * Inc.; the contents of this file may not be disclosed to third
 * parties, copied or duplicated in any form, in whole or in part,
 * without the prior written permission of Silicon Graphics, Inc.
 *
 * RESTRICTED RIGHTS LEGEND:
 * Use, duplication or disclosure by the Government is subject to
 * restrictions as set forth in subdivision (c)(1)(ii) of the Rights
 * in Technical Data and Computer Software clause at DFARS
 * 252.227-7013, and/or in similar or successor clauses in the FAR,
 * DOD or NASA FAR Supplement. Unpublished - rights reserved under the
 * Copyright Laws of the United States.
 *====================================================================*/

#include <libaudio.h>
#include <os_internal.h>
#include <ultraerror.h>
#include <assert.h>
#include "n_libaudio.h"
#include "n_seqp.h"
#include "seq.h"


static  ALMicroTime     __n_seqpVoiceHandler(void *node);
static  void            __n_HandleMIDIMsg(N_ALSeqPlayer *seqp, N_ALEvent *event);
static  void            __n_handleMetaMsg(N_ALSeqPlayer *seqp, N_ALEvent *event);
static	void		__n_handleNextSeqEvent(N_ALSeqPlayer *seqp);
static	void		__n_setUsptFromTempo(N_ALSeqPlayer *seqp, f32 tempo);	/* sct 1/8/96 */

/*
 * Sequence Player public functions
 */
void n_alSeqpNew(N_ALSeqPlayer *seqp, ALSeqpConfig *c)
{
    s32                 i;
    N_ALEventListItem     *items;
    N_ALVoiceState        *vs;
    N_ALVoiceState        *voices;
    ALHeap *hp = c->heap;    
    
    /*
     * initialize member variables
     */
    seqp->bank          = 0;
    seqp->target        = NULL;
    seqp->drvr          = n_syn;
    seqp->chanMask      = 0xff;
    seqp->uspt          = 488;
    seqp->nextDelta     = 0;
    seqp->state         = AL_STOPPED;
    seqp->vol           = 0x7FFF;                  /* full volume  */
    seqp->debugFlags    = c->debugFlags;
    seqp->frameTime     = AL_USEC_PER_FRAME; /* should get this from driver */
    seqp->curTime       = 0;
    seqp->initOsc       = c->initOsc;
    seqp->updateOsc     = c->updateOsc;
    seqp->stopOsc       = c->stopOsc;
    seqp->loopStart = 0;
    seqp->loopEnd   = 0;
    seqp->loopCount = 0;      /* -1 = loop forever, 0 = no loop   */
    
    seqp->nextEvent.type = AL_SEQP_API_EVT; /* start the voice handler "spinning" */
    
    /*
     * init the channel state
     */
    seqp->maxChannels = c->maxChannels;
    seqp->chanState = alHeapAlloc(hp, c->maxChannels, sizeof(ALChanState) );
    __n_initChanState(seqp);	/* sct 11/6/95 */
    
    /*
     * init the voice state array
     */
    voices = alHeapAlloc(hp, c->maxVoices, sizeof(N_ALVoiceState));
    seqp->vFreeList = 0;
    for (i = 0; i < c->maxVoices; i++) {
        vs = &voices[i];
        vs->next = seqp->vFreeList;
        seqp->vFreeList = vs;        
    }
    
    seqp->vAllocHead = 0;
    seqp->vAllocTail = 0;    
        
    /*
     * init the event queue
     */
    items = alHeapAlloc(hp, c->maxEvents, sizeof(N_ALEventListItem));
    n_alEvtqNew(&seqp->evtq, items, c->maxEvents);

    /*
     * add ourselves to the driver
     */
    
    seqp->node.next       = NULL;
    seqp->node.handler    = __n_seqpVoiceHandler;
    seqp->node.clientData = seqp;
    n_alSynAddSeqPlayer( &seqp->node);
}

/*************************************************************
 * private routines or driver callback routines
 *************************************************************/
static ALMicroTime 
__n_seqpVoiceHandler(void *node)
{
    N_ALSeqPlayer     *seqp = (N_ALSeqPlayer *) node;
    N_ALEvent         evt;
    N_ALVoice         *voice;
    ALMicroTime     delta;
    N_ALVoiceState    *vs;
    void            *oscState;
    f32		    oscValue;
    u8              chan;
    
    do {

	switch (seqp->nextEvent.type) {

	  case (AL_SEQ_REF_EVT):
	      __n_handleNextSeqEvent(seqp);
              break;

	  case (AL_SEQP_API_EVT):
              evt.type = AL_SEQP_API_EVT;
              n_alEvtqPostEvent(&seqp->evtq, (N_ALEvent *)&evt, seqp->frameTime);
              break;

	  case (AL_NOTE_END_EVT):
              voice = seqp->nextEvent.msg.note.voice;
              n_alSynStopVoice(voice);
              n_alSynFreeVoice(voice);
              vs = (N_ALVoiceState *)voice->clientPrivate;
              if(vs->flags)
                  __n_seqpStopOsc((N_ALSeqPlayer*)seqp,vs);
              __n_unmapVoice(seqp, voice);
              break;

	  case (AL_SEQP_ENV_EVT):
              voice = seqp->nextEvent.msg.vol.voice;
              vs = (N_ALVoiceState *)voice->clientPrivate;
                
              if (vs->envPhase == AL_PHASE_ATTACK)
                  vs->envPhase = AL_PHASE_DECAY;

              delta = seqp->nextEvent.msg.vol.delta;
              vs->envGain = seqp->nextEvent.msg.vol.vol;
              vs->envEndTime = seqp->curTime + delta;
              n_alSynSetVol(voice, __n_vsVol(vs, seqp), delta);
              break;

	  case (AL_TREM_OSC_EVT):
              vs = seqp->nextEvent.msg.osc.vs;
              oscState = seqp->nextEvent.msg.osc.oscState;
              delta = (*seqp->updateOsc)(oscState,&oscValue);
              vs->tremelo = (u8)oscValue;
              n_alSynSetVol(&vs->voice, __n_vsVol(vs,seqp),
                          __n_vsDelta(vs,seqp->curTime));
              evt.type = AL_TREM_OSC_EVT;
              evt.msg.osc.vs = vs;
              evt.msg.osc.oscState = oscState;
              n_alEvtqPostEvent(&seqp->evtq, &evt, delta);
              break;
                
	  case (AL_VIB_OSC_EVT):
              vs = seqp->nextEvent.msg.osc.vs;
              oscState = seqp->nextEvent.msg.osc.oscState;
              chan = seqp->nextEvent.msg.osc.chan;
              delta = (*seqp->updateOsc)(oscState,&oscValue);
              vs->vibrato = oscValue;
              n_alSynSetPitch(&vs->voice, vs->pitch * vs->vibrato
                            * seqp->chanState[chan].pitchBend);
              evt.type = AL_VIB_OSC_EVT;
              evt.msg.osc.vs = vs;
              evt.msg.osc.oscState = oscState;
              evt.msg.osc.chan = chan;
              n_alEvtqPostEvent(&seqp->evtq, &evt, delta);
              break;
                
	  case (AL_SEQP_MIDI_EVT):
              __n_HandleMIDIMsg(seqp, &seqp->nextEvent);
              break;

	  case (AL_SEQP_META_EVT):
              __n_handleMetaMsg(seqp, &seqp->nextEvent);
              break;
              
	  case (AL_SEQP_PLAY_EVT):
	      if (seqp->state != AL_PLAYING)
	      {
	          seqp->state = AL_PLAYING;
	          __n_postNextSeqEvent(seqp);	/* seqp must be AL_PLAYING before we call this routine. */
	      }
	      break;

	  case (AL_SEQP_STOP_EVT):
              if ( seqp->state == AL_STOPPING )
	      {
                  for (vs = seqp->vAllocHead; vs != 0; vs = seqp->vAllocHead)
                  {
                      n_alSynStopVoice(&vs->voice);
                      n_alSynFreeVoice(&vs->voice);
                      if(vs->flags)
                          __n_seqpStopOsc((N_ALSeqPlayer*)seqp,vs);
                      __n_unmapVoice((N_ALSeqPlayer*)seqp, &vs->voice); 
                  }

                  seqp->curTime = 0;
                  seqp->state = AL_STOPPED;

                  /* alEvtqFlush(&seqp->evtq); - Don't flush event
                     queue anymore. */
		  /* sct 1/3/96 - Don't overwrite nextEvent with
		     AL_SEQP_API_EVT or set nextDelta to
		     AL_USEC_PER_FRAME since we're not stopping event
		     processing. */
		  /* sct 1/3/96 - Don't return here since we keep
                     processing events as usual. */
              }
              break;

	  case (AL_SEQP_STOPPING_EVT):
              if (seqp->state == AL_PLAYING)
	      {
		  /*
                   * sct 12/29/95 - Remove events associated with the
                   * stopping sequence.  Note that flushing
                   * AL_SEQP_MIDI_EVTs may flush events that were
                   * posted after the call to alSeqpStop, so the
                   * application must queue these events either when
                   * the player is fully stopped, or when it is
                   * playing.
                   */
		  n_alEvtqFlushType(&seqp->evtq, AL_SEQ_REF_EVT);
		  n_alEvtqFlushType(&seqp->evtq, AL_SEQP_MIDI_EVT);	

		  /*
                   * sct 1/3/96 - Check to see which voices need to be
                   * killed and release them.  Unkilled voices should
                   * have note end events occurring prior to
                   * KILL_TIME.
                   */
                  for (vs = seqp->vAllocHead; vs != 0; vs = vs->next)
		  {
		      if (__n_voiceNeedsNoteKill (seqp, &vs->voice, KILL_TIME))
			  __n_seqpReleaseVoice(seqp, &vs->voice, KILL_TIME);
		  }

                  seqp->state = AL_STOPPING;
                  evt.type = AL_SEQP_STOP_EVT;
                  n_alEvtqPostEvent(&seqp->evtq, &evt, AL_EVTQ_END);
              }
              break;

	  case (AL_SEQP_VOL_EVT):
              seqp->vol = seqp->nextEvent.msg.spvol.vol;
              for (vs = seqp->vAllocHead; vs != 0; vs = vs->next) {
                  n_alSynSetVol(&vs->voice, __n_vsVol(vs, seqp),
                              __n_vsDelta(vs, seqp->curTime));
              }
              break;
            
	  case (AL_SEQP_LOOP_EVT):
              seqp->loopStart = seqp->nextEvent.msg.loop.start;
              seqp->loopEnd   = seqp->nextEvent.msg.loop.end;
              seqp->loopCount = seqp->nextEvent.msg.loop.count;
              break;

	  case (AL_SEQP_PRIORITY_EVT):
	      chan = seqp->nextEvent.msg.sppriority.chan;
	      seqp->chanState[chan].priority = seqp->nextEvent.msg.sppriority.priority;
	      break;

	  case (AL_SEQP_SEQ_EVT):

#ifdef _DEBUG
	      assert(seqp->state != AL_PLAYING);	/* Must be done playing to change sequences. */
#endif
    
	      seqp->target = seqp->nextEvent.msg.spseq.seq;
	      __n_setUsptFromTempo (seqp, 500000.0);
	      if (seqp->bank)
		  __n_initFromBank(seqp, seqp->bank);
	      break;

	  case (AL_SEQP_BANK_EVT):

#ifdef _DEBUG
	      assert(seqp->state == AL_STOPPED);	/* Must be fully stopped to change banks. */
#endif
    
	      seqp->bank = seqp->nextEvent.msg.spbank.bank;
	      __n_initFromBank(seqp, seqp->bank);
	      break;

	  /* sct 11/6/95 - these events should now be handled by __n_handleNextSeqEvent */
	  case (AL_SEQ_END_EVT):
	  case (AL_TEMPO_EVT):
          case (AL_SEQ_MIDI_EVT):

#ifdef _DEBUG
	      assert(FALSE);	
#endif

              break;
        }

	seqp->nextDelta = n_alEvtqNextEvent (&seqp->evtq, &seqp->nextEvent);
	
    } while (seqp->nextDelta == 0);

    /*
     * assume that next callback won't be more than half an hour away
     */
    seqp->curTime += seqp->nextDelta;	/* Update the player's current time. */
    return seqp->nextDelta;
}


/*
  Call this routine to handle the next event in the sequence.
  Assumes that the next sequence event is scheduled to be processed
  immediately since it does not check the event's tick time.

  sct 11/7/95
*/
static void
__n_handleNextSeqEvent(N_ALSeqPlayer *seqp)
{
    N_ALEvent	evt;

    /* sct 1/5/96 - Do nothing if we don't have a target sequence. */
    if (seqp->target == NULL)
	return;

    n_alSeqNextEvent(seqp->target, &evt);

    switch (evt.type)
    {
    case AL_SEQ_MIDI_EVT:
	__n_HandleMIDIMsg(seqp, &evt);
	__n_postNextSeqEvent(seqp);
	break;

    case AL_TEMPO_EVT:
	__n_handleMetaMsg(seqp, &evt);
	__n_postNextSeqEvent(seqp);
	break;

    case AL_SEQ_END_EVT:
	seqp->state = AL_STOPPING;      
	evt.type    = AL_SEQP_STOP_EVT;
	n_alEvtqPostEvent(&seqp->evtq, &evt, AL_EVTQ_END);
	break;

    default:

#ifdef _DEBUG
	assert(FALSE);	/* Sequence event type not supported. */
#endif

	break;
    }
}


static void 
__n_HandleMIDIMsg(N_ALSeqPlayer *seqp, N_ALEvent *event)
{
    N_ALVoice             *voice;
    N_ALVoiceState        *vs;
    s32                 status;
    u8                  chan;
    u8                  key;
    u8                  vel;
    u8                  byte1;
    u8                  byte2;
    ALMIDIEvent         *midi = &event->msg.midi;
    s16                 vol;
    N_ALEvent             evt;
    ALMicroTime         deltaTime;
    N_ALVoiceState        *vstate;
    ALPan   		    pan;
    ALFxRef		        fxref;

#ifdef _DEBUG
    /* sct 12/15/95 - Fixed assert to also allow seqp midi event types. */
    assert(event->type == AL_SEQ_MIDI_EVT || event->type == AL_SEQP_MIDI_EVT);
#endif
    
    status = midi->status & AL_MIDI_StatusMask;
    chan = midi->status & AL_MIDI_ChannelMask;
    byte1 = key  = midi->byte1;
    byte2 = vel  = midi->byte2;

    switch (status) {

        case (AL_MIDI_NoteOn):
            
            if (vel != 0) {		/* a real note on */
                ALVoiceConfig   config;
                ALSound         *sound;                    
                s16             cents;
                f32             pitch,oscValue;
                u8              fxmix;
                void            *oscState;
                ALInstrument    *inst;

		/* If we're not playing, don't process note ons. */
		if (seqp->state != AL_PLAYING)
		    break;

                sound = __n_lookupSoundQuick(seqp, key, vel, chan);
                ALFlagFailIf(!sound, seqp->debugFlags & NO_SOUND_ERR_MASK,
			   ERR_ALSEQP_NO_SOUND);
                
                config.priority = seqp->chanState[chan].priority;
                config.fxBus    = 0;
                config.unityPitch = 0;

                vstate = __n_mapVoice(seqp, key, vel, chan);
                ALFlagFailIf(!vstate, seqp->debugFlags & NO_VOICE_ERR_MASK,
			 ERR_ALSEQP_NO_VOICE );

                voice = &vstate->voice;
                
                n_alSynAllocVoice(voice, &config);

                /*
                 * set up the voice state structure
                 */
                vstate->sound = sound;
                vstate->envPhase = AL_PHASE_ATTACK;
                if (seqp->chanState[chan].sustain > AL_SUSTAIN)
                    vstate->phase = AL_PHASE_SUSTAIN;
                else
                    vstate->phase = AL_PHASE_NOTEON;
                
                cents = (key - sound->keyMap->keyBase) * 100
                    + sound->keyMap->detune;
                
                vstate->pitch = alCents2Ratio(cents);
                vstate->envGain = sound->envelope->attackVolume;
                vstate->envEndTime = seqp->curTime +
                    sound->envelope->attackTime;

                /*
                 * setup tremelo and vibrato if active
                 */
                vstate->flags = 0;
                inst = seqp->chanState[chan].instrument;

                oscValue = (f32)AL_VOL_FULL; /* set this as a default */

                if(inst->tremType)
                {
                    if(seqp->initOsc)
                    {
                        deltaTime = (*seqp->initOsc)(&oscState,&oscValue,
                                                     inst->tremType,
                                                     inst->tremRate,
                                                     inst->tremDepth,
                                                     inst->tremDelay);

                        if(deltaTime) /* if deltaTime = zero, don't run osc */
                        {
                            evt.type = AL_TREM_OSC_EVT;
                            evt.msg.osc.vs = vstate;
                            evt.msg.osc.oscState = oscState;
                            n_alEvtqPostEvent(&seqp->evtq, &evt, deltaTime);
                            vstate->flags |= 0x01; /* set tremelo flag bit */
                        }
                    }
                }
                /* will default if not changed by initOsc */
                vstate->tremelo = (u8)oscValue;
                
                oscValue = 1.0f; /* set this as a default */
                if(inst->vibType)
                {
                    if(seqp->initOsc)
                    {
                        deltaTime = (*seqp->initOsc)(&oscState,&oscValue,
                                                     inst->vibType,
                                                     inst->vibRate,
                                                     inst->vibDepth,
                                                     inst->vibDelay);

                        if(deltaTime)  /* if deltaTime = zero,don't run osc. */
                        {
                            evt.type = AL_VIB_OSC_EVT;
                            evt.msg.osc.vs = vstate;
                            evt.msg.osc.oscState = oscState;
                            evt.msg.osc.chan = chan;
                            n_alEvtqPostEvent(&seqp->evtq, &evt, deltaTime);
                            vstate->flags |= 0x02; /* set the vibrato flag bit */
                        }
                    }
                }
                /* will default if not changed by initOsc */
                vstate->vibrato = oscValue;

                /*
                 * calculate the note on parameters
                 */
                pitch = vstate->pitch * seqp->chanState[chan].pitchBend *
                    vstate->vibrato;
                fxmix = seqp->chanState[chan].fxmix;
                pan   = __n_vsPan(vstate, seqp);
                vol   = __n_vsVol(vstate, seqp);
                deltaTime  = sound->envelope->attackTime;

                n_alSynStartVoiceParams(voice, sound->wavetable,
                                      pitch, vol, pan, fxmix, deltaTime);
                /*
                 * set up callbacks for envelope
                 */
                evt.type          = AL_SEQP_ENV_EVT;
                evt.msg.vol.voice = voice;
                evt.msg.vol.vol   = sound->envelope->decayVolume;
                evt.msg.vol.delta = sound->envelope->decayTime;
                deltaTime = sound->envelope->attackTime;
                
                n_alEvtqPostEvent(&seqp->evtq, &evt, deltaTime);

                break;
            }

            /*
             * NOTE: intentional fall-through for note on with zero
             * velocity
             */
            
        case (AL_MIDI_NoteOff):
            vstate = __n_lookupVoice(seqp, key, chan);
            ALFlagFailIf(!vstate, (seqp->debugFlags & NOTE_OFF_ERR_MASK),
		       ERR_ALSEQP_OFF_VOICE );

            if (vstate->phase == AL_PHASE_SUSTAIN)
                vstate->phase = AL_PHASE_SUSTREL;
            else {
                vstate->phase = AL_PHASE_RELEASE;
                __n_seqpReleaseVoice(seqp, &vstate->voice,
				   vstate->sound->envelope->releaseTime);
            }

            break;
            
        case (AL_MIDI_PolyKeyPressure):
	    /*
	     * Aftertouch per key (hardwired to volume). Note that
	     * aftertouch affects only notes that are already
	     * sounding.
             */
	    vstate = __n_lookupVoice(seqp, key, chan);
	    ALFailIf(!vstate,  ERR_ALSEQP_POLY_VOICE );

	    vstate->velocity = byte2;
	    n_alSynSetVol(&vstate->voice, __n_vsVol(vstate, seqp),
			__n_vsDelta(vstate, seqp->curTime));
	    break;

        case (AL_MIDI_ChannelPressure):
	    /*
             * Aftertouch per channel (hardwired to volume). Note that
             * aftertouch affects only notes that are already
             * sounding.
             */
	    for (vs = seqp->vAllocHead; vs != 0; vs = vs->next) {
		if (vs->channel == chan) {
		    vs->velocity = byte1;
		    n_alSynSetVol(&vs->voice, __n_vsVol(vs, seqp),
				__n_vsDelta(vs, seqp->curTime));
		}
	    }
            break;
            
        case (AL_MIDI_ControlChange):

	    switch (byte1) {
		  
	    case (AL_MIDI_PAN_CTRL):
		seqp->chanState[chan].pan = byte2;
		for (vs = seqp->vAllocHead; vs != 0; vs = vs->next) {
		    if (vs->channel == chan) {
			pan = __n_vsPan(vs, seqp);
			n_alSynSetPan(&vs->voice, pan);
		    }
		}
		break;

	    case (AL_MIDI_VOLUME_CTRL):
		seqp->chanState[chan].vol = byte2;
		for (vs = seqp->vAllocHead; vs != 0; vs = vs->next) {
		    if ((vs->channel == chan) &&
			(vs->envPhase != AL_PHASE_RELEASE))
		    {
			vol = __n_vsVol(vs, seqp);
			n_alSynSetVol(&vs->voice, vol,
				    __n_vsDelta(vs, seqp->curTime));
		    }
		}
		break;
            case (AL_MIDI_PRIORITY_CTRL):
		/* leave current voices where they are */
		seqp->chanState[chan].priority = byte2;
		break;
	    case (AL_MIDI_SUSTAIN_CTRL):
		seqp->chanState[chan].sustain = byte2;
		for (vs = seqp->vAllocHead; vs != 0; vs = vs->next) {
		    if ((vs->channel == chan) &&
			(vs->phase != AL_PHASE_RELEASE)) {
			if ( byte2 > AL_SUSTAIN ) {
			    /*
			     * sustain pedal down
			     */
			    if (vs->phase == AL_PHASE_NOTEON)
				vs->phase = AL_PHASE_SUSTAIN;
			} else {
			    /*
			     * sustain pedal up
			     */
			    if (vs->phase == AL_PHASE_SUSTAIN)
				vs->phase = AL_PHASE_NOTEON;
			    else if(vs->phase == AL_PHASE_SUSTREL) {
				vs->phase = AL_PHASE_RELEASE;
				__n_seqpReleaseVoice(seqp, &vs->voice,
						   vs->sound->envelope->releaseTime);
			    }
			}
		    }
		}
		break;
	    
	    case (AL_MIDI_FX1_CTRL):
		seqp->chanState[chan].fxmix = byte2;
		for (vs = seqp->vAllocHead; vs != 0; vs = vs->next) {
		    if (vs->channel == chan) {
			n_alSynSetFXMix(&vs->voice, byte2);
		    }
		}
		break;

	    case (AL_MIDI_FX_CTRL_0):
	    case (AL_MIDI_FX_CTRL_1):
	    case (AL_MIDI_FX_CTRL_2):
	    case (AL_MIDI_FX_CTRL_3):
	    case (AL_MIDI_FX_CTRL_4):
	    case (AL_MIDI_FX_CTRL_5):
	    case (AL_MIDI_FX_CTRL_6):
	    case (AL_MIDI_FX_CTRL_7):
#if 0	/* fx control not implemented */      
		fxref = n_alSynGetFXRef(0, 0);
		if (fxref)
		    n_alSynSetFXParam(fxref, (s16)byte1, (void *)byte2);
		break;
#endif
	    case (AL_MIDI_FX3_CTRL):
	    default:
		break;

	    }
            break;

        case (AL_MIDI_ProgramChange):
	    /* sct 1/16/96 - We must have a valid bank in order to process the program change. */

#ifdef _DEBUG
	    assert(seqp->bank != NULL);
#endif

            if (key < seqp->bank->instCount) {
                ALInstrument *inst = seqp->bank->instArray[key];
                __n_setInstChanState(seqp, inst, chan);        /* sct 11/6/95 */
            }
#ifdef _DEBUG
	    else
		__osError(ERR_ALSEQPINVALIDPROG, 2, key, seqp->bank->instCount);
#endif                
            break;
            
        case (AL_MIDI_PitchBendChange):
	    {
		s32 bendVal;
		f32 bendRatio;
		s32 cents;
                
		/*
                 * get 14-bit unsigned midi value
                 */
                bendVal = ( (byte2 << 7) + byte1) - 8192;

                /*
                 * calculate pitch bend in cents
                 */
                cents = (seqp->chanState[chan].bendRange * bendVal)/8192;

                /*
                 * calculate the corresponding ratio
                 */
                bendRatio = alCents2Ratio(cents);
                seqp->chanState[chan].pitchBend = bendRatio;
                
                for (vs = seqp->vAllocHead; vs != 0; vs = vs->next) {
                    if (vs->channel == chan) {
                        n_alSynSetPitch(&vs->voice,
                                      vs->pitch * bendRatio * vs->vibrato);
                    }
                }
            }
            break;
            
        default:
#ifdef _DEBUG
	    __osError(ERR_ALSEQPUNKNOWNMIDI, 1, status);
#endif
	    break;
    }        
}

static void 
__n_handleMetaMsg(N_ALSeqPlayer *seqp, N_ALEvent *event)
{
    ALTempoEvent *tevt = &event->msg.tempo;
    N_ALEvent      evt;
    s32          tempo;

    if (event->msg.tempo.status == AL_MIDI_Meta)
    {
        if (event->msg.tempo.type == AL_MIDI_META_TEMPO)
	{
	    tempo =
		(tevt->byte1 << 16) |
		(tevt->byte2 <<  8) |
		(tevt->byte3 <<  0);
	    __n_setUsptFromTempo (seqp, (f32)tempo);	/* sct 1/8/96 */
        }
    }
}


void __n_unmapVoice(N_ALSeqPlayer *seqp, N_ALVoice *voice) 
{
    N_ALVoiceState *prev = 0;
    N_ALVoiceState *vs;
    
    /*
     * we could use doubly linked lists here and save some code and
     * execution time, but time spent here in negligible, so it won't
     * make much difference.
     */
    for (vs = seqp->vAllocHead; vs != 0; vs = vs->next) {
        if (&vs->voice == voice) {

            if (prev)
                prev->next = vs->next;
            else
                seqp->vAllocHead = vs->next;
            
            if (vs == seqp->vAllocTail) {
                seqp->vAllocTail = prev;
            }

            vs->next = seqp->vFreeList;
            seqp->vFreeList = vs;
            return;

        }
        prev = vs;
    }
#ifdef _DEBUG
    __osError(ERR_ALSEQPUNMAP, 1, voice);
#endif    
}


#ifdef IMPLEMENTED

s32     seqpGetVoices(SEQP *seqp);
s32     seqpSetVoices(SEQP *seqp, s32 numvoices);

u16	seqpGetChannelMask(SEQP *seqp);
s32	seqpSetChannelMask(SEQP *seqp, u16 bitmask);

#endif

void __n_seqpReleaseVoice(N_ALSeqPlayer *seqp, N_ALVoice *voice,
                        ALMicroTime deltaTime)
{
    N_ALEvent             evt;
    N_ALVoiceState	*vs = (N_ALVoiceState *)voice->clientPrivate;

    /*
     * if in attack phase, remove all pending volume
     * events for this voice from the queue
     */

    if (vs->envPhase == AL_PHASE_ATTACK) {
	ALLink              *thisNode;
	ALLink              *nextNode;
	N_ALEventListItem     *thisItem, *nextItem;

	thisNode = seqp->evtq.allocList.next;
	while( thisNode != 0 ) {
	    nextNode = thisNode->next;
	    thisItem = (N_ALEventListItem *)thisNode;
	    nextItem = (N_ALEventListItem *)nextNode;
	    if (thisItem->evt.type == AL_SEQP_ENV_EVT) {
		if(thisItem->evt.msg.vol.voice == voice) {
		    if( nextItem )
			nextItem->delta += thisItem->delta;
		    alUnlink(thisNode);
		    alLink(thisNode, &seqp->evtq.freeList);
		}
	    }
	    thisNode = nextNode;
	}
    }
    
    vs->velocity = 0;
    vs->envPhase = AL_PHASE_RELEASE;
    vs->envGain  = 0;
    vs->envEndTime = seqp->curTime + deltaTime;

    n_alSynSetPriority(voice, 0); /* make candidate for stealing */
    n_alSynSetVol(voice, 0, deltaTime);
    evt.type  = AL_NOTE_END_EVT;
    evt.msg.note.voice = voice;
    
    n_alEvtqPostEvent(&seqp->evtq, &evt, deltaTime);
}



/*
  This special purpose routine is called only when processing
  a stopping event in order to properly kill all active voices.
  
  The routine searches through the seqp's event queue for an
  AL_NOTE_END_EVT for the given voice.  If the event's execution
  time is greater than kill time, it removes the event from the
  event queue and returns true that it needs to kill the voice.
  Otherwise, if the event's time is less than the kill time, it
  returns false that the voice needs to be killed.

  sct 1/3/96
*/

#define VOICENEEDSNOTEKILL_DEBUG	_DEBUG_INTERNAL&&0	/* For debugging voiceNeedsNoteKill routine. */

char __n_voiceNeedsNoteKill (N_ALSeqPlayer *seqp, N_ALVoice *voice, ALMicroTime killTime)
{
    ALLink              *thisNode;
    ALLink              *nextNode;
    N_ALEventListItem     *thisItem;
    ALMicroTime		itemTime = 0;
    char		needsNoteKill = TRUE;

#if VOICENEEDSNOTEKILL_DEBUG
    n_alEvtqPrintAllocEvts (&seqp->evtq);
#endif

    thisNode = seqp->evtq.allocList.next;
    while (thisNode != 0)
    {
	nextNode = thisNode->next;
	thisItem = (N_ALEventListItem *)thisNode;
	itemTime += thisItem->delta;

	if (thisItem->evt.type == AL_NOTE_END_EVT)
	{
	    if (thisItem->evt.msg.note.voice == voice)
	    {
		if (itemTime > killTime)
		{
		    if ((N_ALEventListItem *)nextNode)
			((N_ALEventListItem *)nextNode)->delta += thisItem->delta;
		    alUnlink(thisNode);
		    alLink(thisNode, &seqp->evtq.freeList);
		}
		else
		    needsNoteKill = FALSE;
		break;
	    }
	}
	thisNode = nextNode;
    }

#if VOICENEEDSNOTEKILL_DEBUG 
    if (thisNode)
	osSyncPrintf("vox 0x%0x: end time %d  kill time %d\n\n", voice, itemTime, killTime);
    else
	osSyncPrintf("vox 0x%0x: not found\n\n", voice);

    n_alEvtqPrintAllocEvts (&seqp->evtq);
#endif

   return needsNoteKill;
}


/*
  This routine safely calculates the sequence player's
  uspt value based on the given tempo.  It does this safely
  by making sure that the player has a target sequence and
  therefore a qnpt value which is needed for the calculation.
*/
static void 
__n_setUsptFromTempo (N_ALSeqPlayer *seqp, f32 tempo)
{
    if (seqp->target)
	seqp->uspt = (s32)((f32)tempo * seqp->target->qnpt);
    else
	seqp->uspt = 488;		/* This is the initial value set by alSeqpNew. */
}


N_ALVoiceState *__n_mapVoice(N_ALSeqPlayer *seqp, u8 key, u8 vel, u8 channel)
{
    N_ALVoiceState  *vs = seqp->vFreeList;

    if (vs) {

        seqp->vFreeList = vs->next;

        vs->next = 0;
        
        if (!seqp->vAllocHead)
            seqp->vAllocHead = vs;
        else
            seqp->vAllocTail->next = vs;
        
        seqp->vAllocTail = vs;

        vs->channel             = channel;
        vs->key                 = key;
        vs->velocity            = vel;
        vs->voice.clientPrivate = vs;
    }
    
    return vs;
}


N_ALVoiceState *__n_lookupVoice(N_ALSeqPlayer *seqp, u8 key, u8 channel)
{
    N_ALVoiceState  *vs;

    for (vs = seqp->vAllocHead; vs != 0; vs = vs->next) {
        if ((vs->key == key) && (vs->channel == channel) &&
            (vs->phase != AL_PHASE_RELEASE) && (vs->phase != AL_PHASE_SUSTREL))
            return vs;
    }
    
    return 0;
}


#if 0
ALSound *__n_lookupSound(N_ALSeqPlayer *seqp, u8 key, u8 vel, u8 chan)
{
    s32         i;
    ALInstrument  *inst = seqp->chanState[chan].instrument;
    ALSound       *snd = 0;
    
    for (i = 0; i < inst->soundCount; i++) {
        ALSound *sound = inst->soundArray[i];
        ALKeyMap *keymap = sound->keyMap;
        
        if ((key >= keymap->keyMin) && (key <= keymap->keyMax) &&
            (vel >= keymap->velocityMin) && (vel <= keymap->velocityMax)) {
            snd = sound;
            break;
        }
    }
    return snd;
}
#endif


ALSound *__n_lookupSoundQuick(N_ALSeqPlayer *seqp, u8 key, u8 vel, u8 chan)
{
    ALInstrument *inst = seqp->chanState[chan].instrument;
    s32 l = 1;
    s32 r = inst->soundCount;
    s32 i;
    ALKeyMap *keymap;

#ifdef _DEBUG
    assert(inst != NULL);       /* sct 10/31/95 - If inst is NULL, then the seqp probably wasn't setup correctly. */
#endif
    
    while (r >= l) {
        i = (l+r)/2;

        keymap = inst->soundArray[i-1]->keyMap;

        if ((key >= keymap->keyMin) && (key <= keymap->keyMax) &&
            (vel >= keymap->velocityMin) && (vel <= keymap->velocityMax)) {
            return inst->soundArray[i-1];
        } else if ((key < keymap->keyMin) ||
                   ((vel < keymap->velocityMin) && (key <= keymap->keyMax))) {
            r = i - 1;
        } else {
            l = i + 1;
        }
    }
    
    return 0;
}



/*
 * __n_vsVol calculates the target volume for the voice based on the
 * note on velocity, envelope, sampleVolume and controller.
 */
s16 __n_vsVol(N_ALVoiceState *vs, N_ALSeqPlayer *seqp) 
{

    u32     t1,t2;

    t1 = (vs->tremelo*vs->velocity*vs->envGain) >> 6;
    t2 = (vs->sound->sampleVolume*seqp->vol*
          seqp->chanState[vs->channel].vol) >> 14;

    t1 *= t2;
    t1 >>= 15;
    
    return( (s16)t1 );
    
}


ALMicroTime __n_vsDelta(N_ALVoiceState *vs, ALMicroTime t)
{
    /*
     * If we are interrupting a previously set envelope segment, we
     * need to recalculate the segment end time given the current
     * time. Note: this routine assumes that the voice is currently
     * playing.
     */
    
    s32 delta = vs->envEndTime - t;
    
    if (delta >= 0) {
        return delta;
    } else {
        return AL_GAIN_CHANGE_TIME;
    }
}


ALPan __n_vsPan(N_ALVoiceState *vs, N_ALSeqPlayer *seqp) 
{
    s32 tmp;

    tmp = seqp->chanState[vs->channel].pan - AL_PAN_CENTER +
        vs->sound->samplePan;
    tmp = MAX(tmp, AL_PAN_LEFT);
    tmp = MIN(tmp, AL_PAN_RIGHT);

    return (ALPan) tmp;
}


void __n_initFromBank(N_ALSeqPlayer *seqp, ALBank *b)
{
    /*
     * init the chanState with the default instrument
     */
    s32 i;    
    ALInstrument *inst = 0;
    
    /* set to the first available instrument. */
    for(i = 0; !inst ; i++)
      inst = b->instArray[i];
    
    /* sct 11/6/95 - Setup the channel state for the given instrument. */
    /* There is some wasted effort here since both calls the same state vars */
    /* but it's safer. */
    for (i = 0; i < seqp->maxChannels; i++) {
      __n_resetPerfChanState(seqp, i);
      __n_setInstChanState(seqp, inst, i);
    }

    if (b->percussion) {
      __n_resetPerfChanState(seqp, i);
      __n_setInstChanState(seqp, b->percussion, 9);
    }
}


/*
  sct 11/6/95 - Called only when creating a new sequence player.
*/
void __n_initChanState(N_ALSeqPlayer *seqp) 
{
    int i;
    
    for (i = 0; i < seqp->maxChannels; i++)
    {
        seqp->chanState[i].instrument = 0;
	__n_resetPerfChanState (seqp, i);
    }
}


/*
  sct 11/6/95 -- Call this whenever a new sequence is to be played or when
  initializing a sequence player.
*/
void __n_resetPerfChanState(N_ALSeqPlayer *seqp, s32 chan) 
{
  seqp->chanState[chan].fxId = AL_FX_NONE;
  seqp->chanState[chan].fxmix = AL_DEFAULT_FXMIX;
  seqp->chanState[chan].pan = AL_PAN_CENTER;
  seqp->chanState[chan].vol = AL_VOL_FULL;
  seqp->chanState[chan].priority = AL_DEFAULT_PRIORITY;
  seqp->chanState[chan].sustain = 0;
  seqp->chanState[chan].bendRange = 200;
  seqp->chanState[chan].pitchBend = 1.0f;
}


/*
  sct 11/6/95 - Call this whenever a new instrument gets assigned to a channel
  such as when changing banks or in response to a MIDI program change event.
  Currently also gets called when changing sequences.
*/
void __n_setInstChanState(N_ALSeqPlayer *seqp, ALInstrument *inst, s32 chan)
{
    seqp->chanState[chan].instrument = inst;
    seqp->chanState[chan].pan = inst->pan;
    seqp->chanState[chan].vol = inst->volume;
    seqp->chanState[chan].priority = inst->priority;
    seqp->chanState[chan].bendRange = inst->bendRange;
}


void __n_seqpStopOsc(N_ALSeqPlayer *seqp, N_ALVoiceState *vs)
{
    N_ALEventListItem  *thisNode,*nextNode;
    s16              evtType;
    
    thisNode = (N_ALEventListItem*)seqp->evtq.allocList.next;
    while(thisNode)
    {
        nextNode = (N_ALEventListItem*)thisNode->node.next;
        evtType = thisNode->evt.type;
        if(evtType == AL_TREM_OSC_EVT || evtType == AL_VIB_OSC_EVT)
        {
            if(thisNode->evt.msg.osc.vs == vs)
            {
                (*seqp->stopOsc)(thisNode->evt.msg.osc.oscState);
                alUnlink((ALLink*)thisNode);
                if(nextNode)
                    nextNode->delta += thisNode->delta;
                alLink((ALLink*)thisNode, &seqp->evtq.freeList);
                if(evtType == AL_TREM_OSC_EVT)
                    vs->flags = vs->flags & 0xFE;
                else /* must be a AL_VIB_OSC_EVT */
                    vs->flags = vs->flags & 0xFD;
                if(!vs->flags)
                    return;  /* there should be no more events */
            }
        }
        
        thisNode = nextNode;
    }
}


void __n_postNextSeqEvent(N_ALSeqPlayer *seqp) 
{
    N_ALEvent     evt;
    s32		deltaTicks;
    ALSeq       *seq = seqp->target;

    /* sct 1/5/96 - Do nothing if we're not playing or don't have a target sequence. */
    if ((seqp->state != AL_PLAYING) || (seq == NULL))
	return;

    /* Get the next event time in ticks. */
    /* If false is returned, then there is no next delta (ie. end of sequence reached). */
    if (!__alSeqNextDelta(seq, &deltaTicks))
	return;

    /* Handle loops. */
    if (seqp->loopCount)
    {
        /* Assume that the loop end falls on a MIDI event. Delta time
           will be correct even if we loop */
        if (alSeqGetTicks(seq) + deltaTicks >= seqp->loopEnd->curTicks)
	{
	    alSeqSetLoc(seq, seqp->loopStart);            

	    if (seqp->loopCount != -1)
		seqp->loopCount--;
	}
    }    

    evt.type = AL_SEQ_REF_EVT;
    n_alEvtqPostEvent(&seqp->evtq, &evt, deltaTicks * seqp->uspt);
}