/**
* @brief Detect the format of message stored in a buffer.
* Determine the message format used in a stream of bytes but check for running status as well.
* @public @memberof MIDIMessageFormat
* @param buffer The message as it would appear on a MIDI cable.
* @param status The running status to use if the buffer does not contain a status byte.
* @return a pointer to the correct message format if the format could be detected.
* @return a NULL pointer if the format could not be detected.
*/
struct MIDIMessageFormat * MIDIMessageFormatDetectRunningStatus( void * buffer, MIDIRunningStatus * status ) {
if( VOID_BYTE(buffer, 0) & 0x80 ) {
return MIDIMessageFormatDetect( buffer );
} else if( status != NULL && *status != 0 ) {
return MIDIMessageFormatDetect( status );
} else {
return NULL;
}
}
/*
* event input callback - just redirect events to subscribers
*/
static int _alsa_input(struct snd_seq_event *ev, int direct, void *private_data,
int atomic, int hop)
{
struct privateData *data = (struct privateData *)private_data;
pr_debug("callback from alsa received of type %d\n", ev->type);
spin_lock(&(data->drv->lock));
if (ev->type == SND_SEQ_EVENT_NOTEON) {
data->msg.data.bytes[0] = 0x90;
} else if (ev->type == SND_SEQ_EVENT_NOTEOFF) {
data->msg.data.bytes[0] = 0x80;
} else {
return 1;
}
//might be changed to ev->data.raw?? for event independant passing
data->msg.data.bytes[0] |= ev->data.note.channel & 0xf;
data->msg.data.bytes[1] = ev->data.note.note;
data->msg.data.bytes[2] = ev->data.note.velocity;
data->msg.data.bytes[3] = 0;
data->msg.data.size = 3;
data->msg.data.data = NULL;
data->msg.format = MIDIMessageFormatDetect(&(data->msg.data.bytes[0]));
pr_debug("found format\n");
data->msg.timestamp = 0;
RTPMIDISessionSend(data->drv->rtpmidi_session, &(data->list));
spin_unlock(&(data->drv->lock));
return 0;
}
/**
* @brief Get a format used for a given status.
* Determine the format that shall be used when accessing messages of
* a known status.
* If the status byte looks like a channel status it is correctly
* shifted so that the correct byte can be checked by MIDIMessageFormatDetect.
* @see MIDIMessageFormatDetect
* @public @memberof MIDIMessageFormat
* @param status A message status.
* @return a pointer to the correct message format if the format could be detected.
* @return a NULL pointer if the format could not be detected or if the given
* status is not an allowed MIDIStatus.
*/
struct MIDIMessageFormat * MIDIMessageFormatForStatus( MIDIStatus status ) {
unsigned char byte;
if( status >= 0x80 ) {
byte = status;
if( byte < 0xf0 ) return NULL; /* messed up channel status? */
} else {
byte = status << 4;
if( byte < 0x80 ) return NULL; /* no status bit? */
}
return MIDIMessageFormatDetect( &byte );
}
