sys/i386/isa/sound/gustest/midithru.c

#include <stdio.h>
#include <sys/soundcard.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <sys/errno.h>

SEQ_DEFINEBUF (2048);
SEQ_PM_DEFINES;

int seqfd, dev = 0;
unsigned char buf[100];
int bufp;

/* LRU list for free operators */

unsigned char free_list[256];
int fhead=0, ftail=0, flen=0;

/* LRU list for still playing notes */

unsigned char note_list[256];
int nhead=0, ntail=0, nlen=0;
unsigned char oper_note[32];

int pgm = 0;
int num_voices;
int bender = 0; /* Initially off */

void
seqbuf_dump ()
{
  if (_seqbufptr)
    if (write (seqfd, _seqbuf, _seqbufptr) == -1)
      {
        perror ("write /dev/sequencer");
        exit (-1);
      }
  _seqbufptr = 0;
}

void
stop_note(int note, int velocity)
{
        int i, op;

        op=255;

        for (i=0;i<num_voices && op==255;i++)
        {
                if (oper_note[i]== note) op=i;
        }

        if (op==255)
         {
           fprintf(stderr, "Note %d off, note not started\n", note);
           fprintf(stderr, "%d, %d\n", flen, nlen);
           return;      /* Has already been killed ??? */
         }

        SEQ_STOP_NOTE(dev, op, note, velocity);
        SEQ_DUMPBUF();

        oper_note[op] = 255;

        free_list[ftail]=op;
        flen++;
        ftail = (ftail+1) % num_voices;

        for (i=0;i<16;i++)
        if (note_list[i] == op) note_list[i] = 255;

        while (nlen && note_list[nhead] == 255)
        {
                nlen--;
                /* printf("Remove from note queue %d, len %d\n", nhead, nlen);  */
                nhead = (nhead+1) % 256;
        }
}

void
kill_one_note()
{
        int oldest;

        if (!nlen) {fprintf(stderr, "Free list empty but no notes playing\n");return;}  /* No notes playing */

        oldest = note_list[nhead];
        nlen--;
        nhead = (nhead+1) % 256;

        fprintf(stderr, "Killing oper %d, note %d\n", oldest, oper_note[oldest]);

        if (oldest== 255) return;       /* Was already stopped. Why? */

        stop_note(oper_note[oldest], 127);
}

void
start_note(int note, int velocity)
{
        int free;

        if (!flen) kill_one_note();

        if (!flen) {printf("** no free voices\n");return;}      /* Panic??? */

        free = free_list[fhead];
        flen--;
        fhead = (fhead+1) % num_voices;

        note_list[ntail] = free;

        if (nlen>255)
         {
#if 0
           fprintf(stderr, "Note list overflow %d, %d, %d\n",
                           nlen, nhead, ntail);
#endif
           nlen=0;      /* Overflow -> hard reset */
         }
        nlen++;
        ntail = (ntail+1) % 256;

        oper_note[free] = note;

        SEQ_SET_PATCH(dev, free, pgm);
        SEQ_PITCHBEND(dev, free, bender);
        SEQ_START_NOTE(dev, free, note, velocity);
        SEQ_DUMPBUF();
}

void
channel_pressure(int ch, int pressure)
{
        int i;

        for (i=0;i<num_voices;i++)
        {
                if (oper_note[i] != 255)
                {
#if 1
                        SEQ_CHN_PRESSURE(dev, i, pressure);
#else
                        SEQ_EXPRESSION(dev, i, pressure);
#endif
                        SEQ_DUMPBUF();
                }
        }
}

void
pitch_bender(int ch, int value)
{
        int i;

        value -= 8192;

        bender = value;

        for (i=0;i<num_voices;i++)
        {
                if (oper_note[i] != 255)
                {
                        bender = value;
                        SEQ_PITCHBEND(dev, i, value);
                        SEQ_DUMPBUF();
                }
        }
}

void
do_buf()
{
        int ch = buf[0] & 0x0f;
        int value;

        switch (buf[0] & 0xf0)
        {
        case 0x90:      /* Note on */
                if (bufp < 3) break;
        /*      printf("Note on %d %d %d\n", ch, buf[1], buf[2]);       */
                if (buf[2])
                   start_note(buf[1], buf[2]);
                else
                   stop_note(buf[1], buf[2]);
                bufp=1;
                break;

        case 0xb0:      /* Control change */
                if (bufp < 3) break;
        /*      printf("Control change %d %d %d\n", ch, buf[1], buf[2]);        */
                bufp=1;
                break;

        case 0x80:      /* Note off */
                if (bufp < 3) break;
        /*      printf("Note off %d %d %d\n", ch, buf[1], buf[2]);      */
                stop_note(buf[1], buf[2]);
                bufp=1;
                break;

        case 0xe0:      /* Pitch bender */
                if (bufp < 3) break;
                value = ((buf[2] & 0x7f) << 7) | (buf[1] & 0x7f);
        /*      printf("Pitch bender %d %d\n", ch, value >> 7);         */
                pitch_bender(ch, value);
                bufp=1;
                break;

        case 0xc0:      /* Pgm change */
                if (bufp < 2) break;
        /*      printf("Pgm change %d %d\n", ch, buf[1]);       */
                pgm = buf[1];
                if (PM_LOAD_PATCH(dev, 0, pgm) < 0)
                 if (errno != ESRCH)    /* No such process */
                     perror("PM_LOAD_PATCH");
                bufp=0;
                break;

        case 0xd0:      /* Channel pressure */
                if (bufp < 2) break;
        /*      printf("Channel pressure %d %d\n", ch, buf[1]); */
                channel_pressure(ch, buf[1]);
                bufp=1;
                break;

        default:
                bufp=0;
        }
}

int
main (int argc, char *argv[])
{
  int i, n, max_voice = 999;

  struct synth_info info;

  unsigned char ev[4], *p;

  if (argc >= 2) dev = atoi(argv[1]);

  for (i=0;i<16;i++) oper_note[i] = 255;

  if ((seqfd = open ("/dev/sequencer", O_RDWR, 0)) == -1)
    {
      perror ("open /dev/sequencer");
      exit (-1);
    }

  if (argc >= 3)
  {
        int d = dev;
        ioctl(seqfd, SNDCTL_FM_4OP_ENABLE, &d);
  }

  info.device = dev;

  if (ioctl(seqfd, SNDCTL_SYNTH_INFO, &info)==-1)
    {
      perror ("info /dev/sequencer");
      exit (-1);
    }

  num_voices = info.nr_voices;
  if (num_voices>max_voice)num_voices = max_voice;
  fprintf(stderr, "Output to synth device %d (%s)\n", dev, info.name);
  fprintf(stderr, "%d voices available\n", num_voices);

  for (i=0;i<num_voices;i++)
  {
        flen++;
        free_list[fhead] = i;
        fhead = (fhead+1) % num_voices;
  }

  bufp = 0;
  if (PM_LOAD_PATCH(dev, 0, 0) < 0) /* Load the default instrument */
  if (errno != ESRCH)   /* No such process */
     perror("PM_LOAD_PATCH");

  while (1)
    {
      if ((n = read (seqfd, ev, sizeof (ev))) == -1)
        {
          perror ("read /dev/sequencer");
          exit (-1);
        }

      for (i = 0; i <= (n / 4); i++)
        {
          p = &ev[i * 4];

          if (p[0] == SEQ_MIDIPUTC && p[2] == 0 /* Midi if# == 0 */)
            {
/*            printf("%02x ", p[1]);fflush(stdout);             */
              if (p[1] & 0x80)  /* Status */
                {
                  if (bufp)
                    do_buf ();
                  buf[0] = p[1];
                  bufp = 1;
                }
              else if (bufp)
                {
                  buf[bufp++] = p[1];
                  if ((buf[0] & 0xf0) == 0x90 || (buf[0] & 0xf0) == 0x80 || (buf[0] & 0xf0) == 0xb0 ||
                      (buf[0] & 0xf0) == 0xe0)
                    {
                      if (bufp == 3)
                        do_buf ();
                    }
                  else
                    if ((buf[0] & 0xf0) == 0xc0 || (buf[0] & 0xf0) == 0xd0)
                    {
                      if (bufp == 2) do_buf();
                    }
                }
            }
        }
    }

  exit (0);
}