diff options
Diffstat (limited to 'spa/plugins/bluez5/midi-parser.c')
| -rw-r--r-- | spa/plugins/bluez5/midi-parser.c | 295 |
1 files changed, 295 insertions, 0 deletions
diff --git a/spa/plugins/bluez5/midi-parser.c b/spa/plugins/bluez5/midi-parser.c new file mode 100644 index 0000000..ba3cd32 --- /dev/null +++ b/spa/plugins/bluez5/midi-parser.c @@ -0,0 +1,295 @@ +/* BLE MIDI parser + * + * Copyright © 2022 Pauli Virtanen + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice (including the next + * paragraph) shall be included in all copies or substantial portions of the + * Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER + * DEALINGS IN THE SOFTWARE. + */ + +#include <errno.h> + +#include <spa/utils/defs.h> + +#include "midi.h" + +enum midi_event_class { + MIDI_BASIC, + MIDI_SYSEX, + MIDI_SYSCOMMON, + MIDI_REALTIME, + MIDI_ERROR +}; + +static enum midi_event_class midi_event_info(uint8_t status, unsigned int *size) +{ + switch (status) { + case 0x80 ... 0x8f: + case 0x90 ... 0x9f: + case 0xa0 ... 0xaf: + case 0xb0 ... 0xbf: + case 0xe0 ... 0xef: + *size = 3; + return MIDI_BASIC; + case 0xc0 ... 0xcf: + case 0xd0 ... 0xdf: + *size = 2; + return MIDI_BASIC; + case 0xf0: + /* variable; count only status byte here */ + *size = 1; + return MIDI_SYSEX; + case 0xf1: + case 0xf3: + *size = 2; + return MIDI_SYSCOMMON; + case 0xf2: + *size = 3; + return MIDI_SYSCOMMON; + case 0xf6: + case 0xf7: + *size = 1; + return MIDI_SYSCOMMON; + case 0xf8 ... 0xff: + *size = 1; + return MIDI_REALTIME; + case 0xf4: + case 0xf5: + default: + /* undefined MIDI status */ + *size = 0; + return MIDI_ERROR; + } +} + +static void timestamp_set_high(uint16_t *time, uint8_t byte) +{ + *time = (byte & 0x3f) << 7; +} + +static void timestamp_set_low(uint16_t *time, uint8_t byte) +{ + if ((*time & 0x7f) > (byte & 0x7f)) + *time += 0x80; + + *time &= ~0x7f; + *time |= byte & 0x7f; +} + +int spa_bt_midi_parser_parse(struct spa_bt_midi_parser *parser, + const uint8_t *src, size_t src_size, bool only_time, + void (*event)(void *user_data, uint16_t time, uint8_t *event, size_t event_size), + void *user_data) +{ + const uint8_t *src_end = src + src_size; + uint8_t running_status = 0; + uint16_t time; + uint8_t byte; + +#define NEXT() do { if (src == src_end) return -EINVAL; byte = *src++; } while (0) +#define PUT(byte) do { if (only_time) { parser->size++; break; } \ + if (parser->size == sizeof(parser->buf)) return -ENOSPC; \ + parser->buf[parser->size++] = (byte); } while (0) + + /* Header */ + NEXT(); + if (!(byte & 0x80)) + return -EINVAL; + timestamp_set_high(&time, byte); + + while (src < src_end) { + NEXT(); + + if (!parser->sysex) { + uint8_t status = 0; + unsigned int event_size; + + if (byte & 0x80) { + /* Timestamp */ + timestamp_set_low(&time, byte); + NEXT(); + + /* Status? */ + if (byte & 0x80) { + parser->size = 0; + PUT(byte); + status = byte; + } + } + + if (status == 0) { + /* Running status */ + parser->size = 0; + PUT(running_status); + PUT(byte); + status = running_status; + } + + switch (midi_event_info(status, &event_size)) { + case MIDI_BASIC: + running_status = (event_size > 1) ? status : 0; + break; + case MIDI_REALTIME: + case MIDI_SYSCOMMON: + /* keep previous running status */ + break; + case MIDI_SYSEX: + parser->sysex = true; + /* XXX: not fully clear if SYSEX can be running status, assume no */ + running_status = 0; + continue; + default: + goto malformed; + } + + /* Event data */ + while (parser->size < event_size) { + NEXT(); + if (byte & 0x80) { + /* BLE MIDI allows no interleaved events */ + goto malformed; + } + PUT(byte); + } + + event(user_data, time, parser->buf, parser->size); + } else { + if (byte & 0x80) { + /* Timestamp */ + timestamp_set_low(&time, byte); + NEXT(); + + if (byte == 0xf7) { + /* Sysex end */ + PUT(byte); + event(user_data, time, parser->buf, parser->size); + parser->sysex = false; + } else { + /* Interleaved realtime event */ + unsigned int event_size; + + if (midi_event_info(byte, &event_size) != MIDI_REALTIME) + goto malformed; + spa_assert(event_size == 1); + event(user_data, time, &byte, 1); + } + } else { + PUT(byte); + } + } + } + +#undef NEXT +#undef PUT + + return 0; + +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 +} |