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bluez5: implement BLE midi data writer

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Pauli Virtanen 2022-11-04 20:58:56 +02:00 • committed by Wim Taymans
parent e3cf7f6d87
commit 5d6f25e8f0
2 changed files with 135 additions and 1 deletions
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90
spa/plugins/bluez5/midi-parser.c
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@ -203,3 +203,93 @@ malformed:
/* Error (potentially recoverable) */
return -EINVAL;
}
int spa_bt_midi_writer_write(struct spa_bt_midi_writer *writer,
uint64_t time, const uint8_t *event, size_t event_size)
{
/* BLE MIDI-1.0: maximum payload size is MTU - 3 */
const unsigned int max_size = writer->mtu - 3;
const uint64_t time_msec = (time / SPA_NSEC_PER_MSEC);
const uint16_t timestamp = time_msec & 0x1fff;
#define PUT(byte) do { if (writer->size >= max_size) return -ENOSPC; \
writer->buf[writer->size++] = (byte); } while (0)
if (writer->mtu < 5+3)
return -ENOSPC; /* all events must fit */
spa_assert(max_size <= sizeof(writer->buf));
spa_assert(writer->size <= max_size);
if (event_size == 0)
return 0;
if (writer->flush) {
writer->flush = false;
writer->size = 0;
}
if (writer->size == max_size)
goto flush;
/* Packet header */
if (writer->size == 0) {
PUT(0x80 | (timestamp >> 7));
writer->running_status = 0;
writer->running_time_msec = time_msec;
}
/* Timestamp low bits can wrap around, but not multiple times */
if (time_msec > writer->running_time_msec + 0x7f)
goto flush;
spa_assert(writer->pos < event_size);
for (; writer->pos < event_size; ++writer->pos) {
const unsigned int unused = max_size - writer->size;
const uint8_t byte = event[writer->pos];
if (byte & 0x80) {
enum midi_event_class class;
unsigned int expected_size;
class = midi_event_info(event[0], &expected_size);
if (class == MIDI_BASIC && expected_size > 1 &&
writer->running_status == byte &&
writer->running_time_msec == time_msec) {
/* Running status: continue with data */
continue;
}
if (unused < expected_size + 1)
goto flush;
/* Timestamp before status */
PUT(0x80 | (timestamp & 0x7f));
writer->running_time_msec = time_msec;
if (class == MIDI_BASIC && expected_size > 1)
writer->running_status = byte;
else
writer->running_status = 0;
} else if (unused == 0) {
break;
}
PUT(byte);
}
if (writer->pos < event_size)
goto flush;
writer->pos = 0;
return 0;
flush:
writer->flush = true;
return 1;
#undef PUT
}