seq_midi_event.c

linux2.6.16版本

			/* process this byte as argument */
			dev->buf[dev->read++] = c;
			dev->qlen = status_event[dev->type].qlen - 1;
		}
	}
	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);
		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 & 0x007f;
	bytes[1] = (ev->data.control.param & 0x3f80) >> 7;
	bytes[2] = ev->data.control.value & 0x007f;
	bytes[3] = (ev->data.control.value & 0x3f80) >> 7;
	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)