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seq_midi_event.c

/*
 *  MIDI byte <-> sequencer event coder
 *
 *  Copyright (C) 1998,99 Takashi Iwai <tiwai@suse.de>,
 *                        Jaroslav Kysela <perex@perex.cz>
 *
 *   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 <linux/slab.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <sound/core.h>
#include <sound/seq_kernel.h>
#include <sound/seq_midi_event.h>
#include <sound/asoundef.h>

MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>, Jaroslav Kysela <perex@perex.cz>");
MODULE_DESCRIPTION("MIDI byte <-> sequencer event coder");
MODULE_LICENSE("GPL");

/* event type, index into status_event[] */
/* from 0 to 6 are normal commands (note off, on, etc.) for 0x9?-0xe? */
#define ST_INVALID      7
#define ST_SPECIAL      8
#define ST_SYSEX  ST_SPECIAL
/* from 8 to 15 are events for 0xf0-0xf7 */


/*
 * prototypes
 */
static void note_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
static void one_param_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
static void pitchbend_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
static void two_param_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
static void one_param_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
static void songpos_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
static void note_decode(struct snd_seq_event *ev, unsigned char *buf);
static void one_param_decode(struct snd_seq_event *ev, unsigned char *buf);
static void pitchbend_decode(struct snd_seq_event *ev, unsigned char *buf);
static void two_param_decode(struct snd_seq_event *ev, unsigned char *buf);
static void songpos_decode(struct snd_seq_event *ev, unsigned char *buf);

/*
 * event list
 */
static struct status_event_list {
      int event;
      int qlen;
      void (*encode)(struct snd_midi_event *dev, struct snd_seq_event *ev);
      void (*decode)(struct snd_seq_event *ev, unsigned char *buf);
} status_event[] = {
      /* 0x80 - 0xef */
      {SNDRV_SEQ_EVENT_NOTEOFF,      2, note_event, note_decode},
      {SNDRV_SEQ_EVENT_NOTEON,       2, note_event, note_decode},
      {SNDRV_SEQ_EVENT_KEYPRESS,     2, note_event, note_decode},
      {SNDRV_SEQ_EVENT_CONTROLLER,   2, two_param_ctrl_event, two_param_decode},
      {SNDRV_SEQ_EVENT_PGMCHANGE,    1, one_param_ctrl_event, one_param_decode},
      {SNDRV_SEQ_EVENT_CHANPRESS,    1, one_param_ctrl_event, one_param_decode},
      {SNDRV_SEQ_EVENT_PITCHBEND,    2, pitchbend_ctrl_event, pitchbend_decode},
      /* invalid */
      {SNDRV_SEQ_EVENT_NONE,        -1, NULL, NULL},
      /* 0xf0 - 0xff */
      {SNDRV_SEQ_EVENT_SYSEX,        1, NULL, NULL}, /* sysex: 0xf0 */
      {SNDRV_SEQ_EVENT_QFRAME,       1, one_param_event, one_param_decode}, /* 0xf1 */
      {SNDRV_SEQ_EVENT_SONGPOS,      2, songpos_event, songpos_decode}, /* 0xf2 */
      {SNDRV_SEQ_EVENT_SONGSEL,      1, one_param_event, one_param_decode}, /* 0xf3 */
      {SNDRV_SEQ_EVENT_NONE,        -1, NULL, NULL}, /* 0xf4 */
      {SNDRV_SEQ_EVENT_NONE,        -1, NULL, NULL}, /* 0xf5 */
      {SNDRV_SEQ_EVENT_TUNE_REQUEST,       0, NULL, NULL}, /* 0xf6 */
      {SNDRV_SEQ_EVENT_NONE,        -1, NULL, NULL}, /* 0xf7 */
      {SNDRV_SEQ_EVENT_CLOCK,        0, NULL, NULL}, /* 0xf8 */
      {SNDRV_SEQ_EVENT_NONE,        -1, NULL, NULL}, /* 0xf9 */
      {SNDRV_SEQ_EVENT_START,        0, NULL, NULL}, /* 0xfa */
      {SNDRV_SEQ_EVENT_CONTINUE,     0, NULL, NULL}, /* 0xfb */
      {SNDRV_SEQ_EVENT_STOP,         0, NULL, NULL}, /* 0xfc */
      {SNDRV_SEQ_EVENT_NONE,        -1, NULL, NULL}, /* 0xfd */
      {SNDRV_SEQ_EVENT_SENSING,      0, NULL, NULL}, /* 0xfe */
      {SNDRV_SEQ_EVENT_RESET,        0, NULL, NULL}, /* 0xff */
};

static int extra_decode_ctrl14(struct snd_midi_event *dev, unsigned char *buf, int len,
                         struct snd_seq_event *ev);
static int extra_decode_xrpn(struct snd_midi_event *dev, unsigned char *buf, int count,
                       struct snd_seq_event *ev);

static struct extra_event_list {
      int event;
      int (*decode)(struct snd_midi_event *dev, unsigned char *buf, int len,
                  struct snd_seq_event *ev);
} extra_event[] = {
      {SNDRV_SEQ_EVENT_CONTROL14, extra_decode_ctrl14},
      {SNDRV_SEQ_EVENT_NONREGPARAM, extra_decode_xrpn},
      {SNDRV_SEQ_EVENT_REGPARAM, extra_decode_xrpn},
};

/*
 *  new/delete record
 */

int snd_midi_event_new(int bufsize, struct snd_midi_event **rdev)
{
      struct snd_midi_event *dev;

      *rdev = NULL;
      dev = kzalloc(sizeof(*dev), GFP_KERNEL);
      if (dev == NULL)
            return -ENOMEM;
      if (bufsize > 0) {
            dev->buf = kmalloc(bufsize, GFP_KERNEL);
            if (dev->buf == NULL) {
                  kfree(dev);
                  return -ENOMEM;
            }
      }
      dev->bufsize = bufsize;
      dev->lastcmd = 0xff;
      dev->type = ST_INVALID;
      spin_lock_init(&dev->lock);
      *rdev = dev;
      return 0;
}

void snd_midi_event_free(struct snd_midi_event *dev)
{
      if (dev != NULL) {
            kfree(dev->buf);
            kfree(dev);
      }
}

/*
 * initialize record
 */
static inline void reset_encode(struct snd_midi_event *dev)
{
      dev->read = 0;
      dev->qlen = 0;
      dev->type = ST_INVALID;
}

void snd_midi_event_reset_encode(struct snd_midi_event *dev)
{
      unsigned long flags;

      spin_lock_irqsave(&dev->lock, flags);
      reset_encode(dev);
      spin_unlock_irqrestore(&dev->lock, flags);
}

void snd_midi_event_reset_decode(struct snd_midi_event *dev)
{
      unsigned long flags;

      spin_lock_irqsave(&dev->lock, flags);
      dev->lastcmd = 0xff;
      spin_unlock_irqrestore(&dev->lock, flags);
}

#if 0
void snd_midi_event_init(struct snd_midi_event *dev)
{
      snd_midi_event_reset_encode(dev);
      snd_midi_event_reset_decode(dev);
}
#endif  /*  0  */

void snd_midi_event_no_status(struct snd_midi_event *dev, int on)
{
      dev->nostat = on ? 1 : 0;
}

/*
 * resize buffer
 */
#if 0
int snd_midi_event_resize_buffer(struct snd_midi_event *dev, int bufsize)
{
      unsigned char *new_buf, *old_buf;
      unsigned long flags;

      if (bufsize == dev->bufsize)
            return 0;
      new_buf = kmalloc(bufsize, GFP_KERNEL);
      if (new_buf == NULL)
            return -ENOMEM;
      spin_lock_irqsave(&dev->lock, flags);
      old_buf = dev->buf;
      dev->buf = new_buf;
      dev->bufsize = bufsize;
      reset_encode(dev);
      spin_unlock_irqrestore(&dev->lock, flags);
      kfree(old_buf);
      return 0;
}
#endif  /*  0  */

/*
 *  read bytes and encode to sequencer event if finished
 *  return the size of encoded bytes
 */
long snd_midi_event_encode(struct snd_midi_event *dev, unsigned char *buf, long count,
                     struct snd_seq_event *ev)
{
      long result = 0;
      int rc;

      ev->type = SNDRV_SEQ_EVENT_NONE;

      while (count-- > 0) {
            rc = snd_midi_event_encode_byte(dev, *buf++, ev);
            result++;
            if (rc < 0)
                  return rc;
            else if (rc > 0)
                  return result;
      }

      return result;
}

/*
 *  read one byte and encode to sequencer event:
 *  return 1 if MIDI bytes are encoded to an event
 *         0 data is not finished
 *         negative for error
 */
int snd_midi_event_encode_byte(struct snd_midi_event *dev, int c,
                         struct snd_seq_event *ev)
{
      int rc = 0;
      unsigned long flags;

      c &= 0xff;

      if (c >= MIDI_CMD_COMMON_CLOCK) {
            /* real-time event */
            ev->type = status_event[ST_SPECIAL + c - 0xf0].event;
            ev->flags &= ~SNDRV_SEQ_EVENT_LENGTH_MASK;
            ev->flags |= SNDRV_SEQ_EVENT_LENGTH_FIXED;
            return ev->type != SNDRV_SEQ_EVENT_NONE;
      }

      spin_lock_irqsave(&dev->lock, flags);
      if ((c & 0x80) &&
          (c != MIDI_CMD_COMMON_SYSEX_END || dev->type != ST_SYSEX)) {
            /* new command */
            dev->buf[0] = c;
            if ((c & 0xf0) == 0xf0) /* system messages */
                  dev->type = (c & 0x0f) + ST_SPECIAL;
            else
                  dev->type = (c >> 4) & 0x07;
            dev->read = 1;
            dev->qlen = status_event[dev->type].qlen;
      } else {
            if (dev->qlen > 0) {
                  /* rest of command */
                  dev->buf[dev->read++] = c;
                  if (dev->type != ST_SYSEX)
                        dev->qlen--;
            } else {
                  /* running status */
                  dev->buf[1] = c;
                  dev->qlen = status_event[dev->type].qlen - 1;
                  dev->read = 2;
            }
      }
      if (dev->qlen == 0) {
            ev->type = status_event[dev->type].event;
            ev->flags &= ~SNDRV_SEQ_EVENT_LENGTH_MASK;
            ev->flags |= SNDRV_SEQ_EVENT_LENGTH_FIXED;
            if (status_event[dev->type].encode) /* set data values */
                  status_event[dev->type].encode(dev, ev);
            if (dev->type >= ST_SPECIAL)
                  dev->type = ST_INVALID;
            rc = 1;
      } else      if (dev->type == ST_SYSEX) {
            if (c == MIDI_CMD_COMMON_SYSEX_END ||
                dev->read >= dev->bufsize) {
                  ev->flags &= ~SNDRV_SEQ_EVENT_LENGTH_MASK;
                  ev->flags |= SNDRV_SEQ_EVENT_LENGTH_VARIABLE;
                  ev->type = SNDRV_SEQ_EVENT_SYSEX;
                  ev->data.ext.len = dev->read;
                  ev->data.ext.ptr = dev->buf;
                  if (c != MIDI_CMD_COMMON_SYSEX_END)
                        dev->read = 0; /* continue to parse */
                  else
                        reset_encode(dev); /* all parsed */
                  rc = 1;
            }
      }

      spin_unlock_irqrestore(&dev->lock, flags);
      return rc;
}

/* encode note event */
static void note_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
{
      ev->data.note.channel = dev->buf[0] & 0x0f;
      ev->data.note.note = dev->buf[1];
      ev->data.note.velocity = dev->buf[2];
}

/* encode one parameter controls */
static void one_param_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
{
      ev->data.control.channel = dev->buf[0] & 0x0f;
      ev->data.control.value = dev->buf[1];
}

/* encode pitch wheel change */
static void pitchbend_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
{
      ev->data.control.channel = dev->buf[0] & 0x0f;
      ev->data.control.value = (int)dev->buf[2] * 128 + (int)dev->buf[1] - 8192;
}

/* encode midi control change */
static void two_param_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
{
      ev->data.control.channel = dev->buf[0] & 0x0f;
      ev->data.control.param = dev->buf[1];
      ev->data.control.value = dev->buf[2];
}

/* encode one parameter value*/
static void one_param_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
{
      ev->data.control.value = dev->buf[1];
}

/* encode song position */
static void songpos_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
{
      ev->data.control.value = (int)dev->buf[2] * 128 + (int)dev->buf[1];
}

/*
 * decode from a sequencer event to midi bytes
 * return the size of decoded midi events
 */
long snd_midi_event_decode(struct snd_midi_event *dev, unsigned char *buf, long count,
                     struct snd_seq_event *ev)
{
      unsigned int cmd, type;

      if (ev->type == SNDRV_SEQ_EVENT_NONE)
            return -ENOENT;

      for (type = 0; type < ARRAY_SIZE(status_event); type++) {
            if (ev->type == status_event[type].event)
                  goto __found;
      }
      for (type = 0; type < ARRAY_SIZE(extra_event); type++) {
            if (ev->type == extra_event[type].event)
                  return extra_event[type].decode(dev, buf, count, ev);
      }
      return -ENOENT;

      __found:
      if (type >= ST_SPECIAL)
            cmd = 0xf0 + (type - ST_SPECIAL);
      else
            /* data.note.channel and data.control.channel is identical */
            cmd = 0x80 | (type << 4) | (ev->data.note.channel & 0x0f);


      if (cmd == MIDI_CMD_COMMON_SYSEX) {
            snd_midi_event_reset_decode(dev);
            return snd_seq_expand_var_event(ev, count, buf, 1, 0);
      } else {
            int qlen;
            unsigned char xbuf[4];
            unsigned long flags;

            spin_lock_irqsave(&dev->lock, flags);
            if ((cmd & 0xf0) == 0xf0 || dev->lastcmd != cmd || dev->nostat) {
                  dev->lastcmd = cmd;
                  spin_unlock_irqrestore(&dev->lock, flags);
                  xbuf[0] = cmd;
                  if (status_event[type].decode)
                        status_event[type].decode(ev, xbuf + 1);
                  qlen = status_event[type].qlen + 1;
            } else {
                  spin_unlock_irqrestore(&dev->lock, flags);
                  if (status_event[type].decode)
                        status_event[type].decode(ev, xbuf + 0);
                  qlen = status_event[type].qlen;
            }
            if (count < qlen)
                  return -ENOMEM;
            memcpy(buf, xbuf, qlen);
            return qlen;
      }
}


/* decode note event */
static void note_decode(struct snd_seq_event *ev, unsigned char *buf)
{
      buf[0] = ev->data.note.note & 0x7f;
      buf[1] = ev->data.note.velocity & 0x7f;
}

/* decode one parameter controls */
static void one_param_decode(struct snd_seq_event *ev, unsigned char *buf)
{
      buf[0] = ev->data.control.value & 0x7f;
}

/* decode pitch wheel change */
static void pitchbend_decode(struct snd_seq_event *ev, unsigned char *buf)
{
      int value = ev->data.control.value + 8192;
      buf[0] = value & 0x7f;
      buf[1] = (value >> 7) & 0x7f;
}

/* decode midi control change */
static void two_param_decode(struct snd_seq_event *ev, unsigned char *buf)
{
      buf[0] = ev->data.control.param & 0x7f;
      buf[1] = ev->data.control.value & 0x7f;
}

/* decode song position */
static void songpos_decode(struct snd_seq_event *ev, unsigned char *buf)
{
      buf[0] = ev->data.control.value & 0x7f;
      buf[1] = (ev->data.control.value >> 7) & 0x7f;
}

/* decode 14bit control */
static int extra_decode_ctrl14(struct snd_midi_event *dev, unsigned char *buf,
                         int count, struct snd_seq_event *ev)
{
      unsigned char cmd;
      int idx = 0;

      cmd = MIDI_CMD_CONTROL|(ev->data.control.channel & 0x0f);
      if (ev->data.control.param < 0x20) {
            if (count < 4)
                  return -ENOMEM;
            if (dev->nostat && count < 6)
                  return -ENOMEM;
            if (cmd != dev->lastcmd || dev->nostat) {
                  if (count < 5)
                        return -ENOMEM;
                  buf[idx++] = dev->lastcmd = cmd;
            }
            buf[idx++] = ev->data.control.param;
            buf[idx++] = (ev->data.control.value >> 7) & 0x7f;
            if (dev->nostat)
                  buf[idx++] = cmd;
            buf[idx++] = ev->data.control.param + 0x20;
            buf[idx++] = ev->data.control.value & 0x7f;
      } else {
            if (count < 2)
                  return -ENOMEM;
            if (cmd != dev->lastcmd || dev->nostat) {
                  if (count < 3)
                        return -ENOMEM;
                  buf[idx++] = dev->lastcmd = cmd;
            }
            buf[idx++] = ev->data.control.param & 0x7f;
            buf[idx++] = ev->data.control.value & 0x7f;
      }
      return idx;
}

/* decode reg/nonreg param */
static int extra_decode_xrpn(struct snd_midi_event *dev, unsigned char *buf,
                       int count, struct snd_seq_event *ev)
{
      unsigned char cmd;
      char *cbytes;
      static char cbytes_nrpn[4] = { MIDI_CTL_NONREG_PARM_NUM_MSB,
                               MIDI_CTL_NONREG_PARM_NUM_LSB,
                               MIDI_CTL_MSB_DATA_ENTRY,
                               MIDI_CTL_LSB_DATA_ENTRY };
      static char cbytes_rpn[4] =  { MIDI_CTL_REGIST_PARM_NUM_MSB,
                               MIDI_CTL_REGIST_PARM_NUM_LSB,
                               MIDI_CTL_MSB_DATA_ENTRY,
                               MIDI_CTL_LSB_DATA_ENTRY };
      unsigned char bytes[4];
      int idx = 0, i;

      if (count < 8)
            return -ENOMEM;
      if (dev->nostat && count < 12)
            return -ENOMEM;
      cmd = MIDI_CMD_CONTROL|(ev->data.control.channel & 0x0f);
      bytes[0] = (ev->data.control.param & 0x3f80) >> 7;
      bytes[1] = ev->data.control.param & 0x007f;
      bytes[2] = (ev->data.control.value & 0x3f80) >> 7;
      bytes[3] = ev->data.control.value & 0x007f;
      if (cmd != dev->lastcmd && !dev->nostat) {
            if (count < 9)
                  return -ENOMEM;
            buf[idx++] = dev->lastcmd = cmd;
      }
      cbytes = ev->type == SNDRV_SEQ_EVENT_NONREGPARAM ? cbytes_nrpn : cbytes_rpn;
      for (i = 0; i < 4; i++) {
            if (dev->nostat)
                  buf[idx++] = dev->lastcmd = cmd;
            buf[idx++] = cbytes[i];
            buf[idx++] = bytes[i];
      }
      return idx;
}

/*
 *  exports
 */
 
EXPORT_SYMBOL(snd_midi_event_new);
EXPORT_SYMBOL(snd_midi_event_free);
EXPORT_SYMBOL(snd_midi_event_reset_encode);
EXPORT_SYMBOL(snd_midi_event_reset_decode);
EXPORT_SYMBOL(snd_midi_event_no_status);
EXPORT_SYMBOL(snd_midi_event_encode);
EXPORT_SYMBOL(snd_midi_event_encode_byte);
EXPORT_SYMBOL(snd_midi_event_decode);

static int __init alsa_seq_midi_event_init(void)
{
      return 0;
}

static void __exit alsa_seq_midi_event_exit(void)
{
}

module_init(alsa_seq_midi_event_init)
module_exit(alsa_seq_midi_event_exit)

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