ALSA: seq: Minor cleanup of MIDI event parser helpers

snd_midi_event_encode_byte() can never fail, and it can return rather
true/false.  Change the return type to bool, adjust the argument to
receive a MIDI byte as unsigned char, and adjust the comment
accordingly.  This allows callers to drop error checks, which
simplifies the code.

Meanwhile, snd_midi_event_encode() helper is used only in seq_midi.c,
and it can be better folded into it.  This will reduce the total
amount of lines in the end.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/seq_midi_event.h

@@ -43,10 +43,8 @@ void snd_midi_event_free(struct snd_midi_event *dev);
 void snd_midi_event_reset_encode(struct snd_midi_event *dev);
 void snd_midi_event_reset_decode(struct snd_midi_event *dev);
 void snd_midi_event_no_status(struct snd_midi_event *dev, int on);
-/* encode from byte stream - return number of written bytes if success */
-long snd_midi_event_encode(struct snd_midi_event *dev, unsigned char *buf, long count,
-			   struct snd_seq_event *ev);
-int snd_midi_event_encode_byte(struct snd_midi_event *dev, int c, struct snd_seq_event *ev);
+bool snd_midi_event_encode_byte(struct snd_midi_event *dev, unsigned char c,
+				struct snd_seq_event *ev);
 /* decode from event to bytes - return number of written bytes if success */
 long snd_midi_event_decode(struct snd_midi_event *dev, unsigned char *buf, long count,
 			   struct snd_seq_event *ev);

sound/core/seq/oss/seq_oss_midi.c

@@ -637,7 +637,7 @@ snd_seq_oss_midi_putc(struct seq_oss_devinfo *dp, int dev, unsigned char c, stru
 
 	if ((mdev = get_mididev(dp, dev)) == NULL)
 		return -ENODEV;
-	if (snd_midi_event_encode_byte(mdev->coder, c, ev) > 0) {
+	if (snd_midi_event_encode_byte(mdev->coder, c, ev)) {
 		snd_seq_oss_fill_addr(dp, ev, mdev->client, mdev->port);
 		snd_use_lock_free(&mdev->use_lock);
 		return 0;

sound/core/seq/seq_midi.c

@@ -78,7 +78,7 @@ static void snd_midi_input_event(struct snd_rawmidi_substream *substream)
 	struct seq_midisynth *msynth;
 	struct snd_seq_event ev;
 	char buf[16], *pbuf;
-	long res, count;
+	long res;
 
 	if (substream == NULL)
 		return;
@@ -94,19 +94,15 @@ static void snd_midi_input_event(struct snd_rawmidi_substream *substream)
 		if (msynth->parser == NULL)
 			continue;
 		pbuf = buf;
-		while (res > 0) {
-			count = snd_midi_event_encode(msynth->parser, pbuf, res, &ev);
-			if (count < 0)
-				break;
-			pbuf += count;
-			res -= count;
-			if (ev.type != SNDRV_SEQ_EVENT_NONE) {
-				ev.source.port = msynth->seq_port;
-				ev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
-				snd_seq_kernel_client_dispatch(msynth->seq_client, &ev, 1, 0);
-				/* clear event and reset header */
-				memset(&ev, 0, sizeof(ev));
-			}
+		while (res-- > 0) {
+			if (!snd_midi_event_encode_byte(msynth->parser,
+							*pbuf++, &ev))
+				continue;
+			ev.source.port = msynth->seq_port;
+			ev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
+			snd_seq_kernel_client_dispatch(msynth->seq_client, &ev, 1, 0);
+			/* clear event and reset header */
+			memset(&ev, 0, sizeof(ev));
 		}
 	}
 }

sound/core/seq/seq_midi_event.c

@@ -214,45 +214,17 @@ int snd_midi_event_resize_buffer(struct snd_midi_event *dev, int bufsize)
 }
 #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;
-}
-EXPORT_SYMBOL(snd_midi_event_encode);
-
 /*
  *  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
+ *  return true if MIDI bytes are encoded to an event
+ *         false data is not finished
  */
-int snd_midi_event_encode_byte(struct snd_midi_event *dev, int c,
-			       struct snd_seq_event *ev)
+bool snd_midi_event_encode_byte(struct snd_midi_event *dev, unsigned char c,
+				struct snd_seq_event *ev)
 {
-	int rc = 0;
+	bool rc = false;
 	unsigned long flags;
 
-	c &= 0xff;
-
 	if (c >= MIDI_CMD_COMMON_CLOCK) {
 		/* real-time event */
 		ev->type = status_event[ST_SPECIAL + c - 0xf0].event;
@@ -293,7 +265,7 @@ int snd_midi_event_encode_byte(struct snd_midi_event *dev, int c,
 			status_event[dev->type].encode(dev, ev);
 		if (dev->type >= ST_SPECIAL)
 			dev->type = ST_INVALID;
-		rc = 1;
+		rc = true;
 	} else 	if (dev->type == ST_SYSEX) {
 		if (c == MIDI_CMD_COMMON_SYSEX_END ||
 		    dev->read >= dev->bufsize) {
@@ -306,7 +278,7 @@ int snd_midi_event_encode_byte(struct snd_midi_event *dev, int c,
 				dev->read = 0; /* continue to parse */
 			else
 				reset_encode(dev); /* all parsed */
-			rc = 1;
+			rc = true;
 		}
 	}
 

sound/core/seq/seq_virmidi.c

@@ -174,8 +174,8 @@ static void snd_vmidi_output_work(struct work_struct *work)
 	while (READ_ONCE(vmidi->trigger)) {
 		if (snd_rawmidi_transmit(substream, &input, 1) != 1)
 			break;
-		if (snd_midi_event_encode_byte(vmidi->parser, input,
-					       &vmidi->event) <= 0)
+		if (!snd_midi_event_encode_byte(vmidi->parser, input,
+						&vmidi->event))
 			continue;
 		if (vmidi->event.type != SNDRV_SEQ_EVENT_NONE) {
 			ret = snd_seq_kernel_client_dispatch(vmidi->client,