[PATCH BlueZ] profiles/midi: Fix zero timestampHigh

[Matthew Cash <matthew@matthew-cash.com>]

BLE-MIDI timestampHigh can legitimately be zero. The MIDI parser used
timestamp_high == 0 to decide whether it had already consumed the packet
header, so packets starting with 0x80 0x80 caused the next running-status
payload byte to be consumed as another timestamp header.

Track whether timestampHigh has been read separately from its value so
packed MIDI events with zero timestampHigh are parsed correctly.
---
 profiles/midi/libmidi.c | 5 ++++-
 profiles/midi/libmidi.h | 2 ++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/profiles/midi/libmidi.c b/profiles/midi/libmidi.c
index 6f2914a8c..ef33f7dfd 100644
--- a/profiles/midi/libmidi.c
+++ b/profiles/midi/libmidi.c
@@ -110,6 +110,7 @@ int midi_read_init(struct midi_read_parser *parser)
 	parser->timestamp = 0;
 	parser->timestamp_low = 0;
 	parser->timestamp_high = 0;
+	parser->timestamp_high_set = false;
 
 	parser->sysex_stream.data = malloc(MIDI_SYSEX_MAX_SIZE);
 	if (!parser->sysex_stream.data)
@@ -355,8 +356,10 @@ size_t midi_read_raw(struct midi_read_parser *parser, const uint8_t *data,
 	size_t i = 0;
 	bool err = false;
 
-	if (parser->timestamp_high == 0)
+	if (!parser->timestamp_high_set) {
 		parser->timestamp_high = data[i++] & 0x3F;
+		parser->timestamp_high_set = true;
+	}
 
 	snd_midi_event_reset_encode(parser->midi_ev);
 
diff --git a/profiles/midi/libmidi.h b/profiles/midi/libmidi.h
index 41f522dd4..9d314cc11 100644
--- a/profiles/midi/libmidi.h
+++ b/profiles/midi/libmidi.h
@@ -83,6 +83,7 @@ struct midi_read_parser {
 	int16_t timestamp;               /* last MIDI-BLE timestamp */
 	int8_t timestamp_low;            /* MIDI-BLE timestampLow from the current packet */
 	int8_t timestamp_high;           /* MIDI-BLE timestampHigh from the current packet */
+	bool timestamp_high_set;         /* timestampHigh read for current packet */
 	struct midi_buffer sysex_stream; /* SysEx stream */
 	snd_midi_event_t *midi_ev;       /* midi<->seq event */
 };
@@ -100,6 +101,7 @@ static inline void midi_read_reset(struct midi_read_parser *parser)
 	parser->rstatus = 0;
 	parser->timestamp_low = 0;
 	parser->timestamp_high = 0;
+	parser->timestamp_high_set = false;
 }
 
 /* Parses raw BLE-MIDI messages and populates a sequencer event representing the
-- 
2.54.0