Add a Raw MIDI parser (based on ALSA raw MIDI)

3 files changed, 208 insertions, 0 deletions

diff --git a/libs/ardour/ardour/raw_midi_parser.h b/libs/ardour/ardour/raw_midi_parser.h
new file mode 100644
index 0000000000..3e1e70066b
--- /dev/null
+++ b/libs/ardour/ardour/raw_midi_parser.h
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2014,2017 Robin Gareus <robin@gareus.org>
+ * Copyright (C) 2010 Devin Anderson
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+#ifndef _ardour_raw_midi_parser_h_
+#define _ardour_raw_midi_parser_h_
+
+#include "ardour/libardour_visibility.h"
+#include "ardour/types.h"
+
+namespace ARDOUR {
+
+class LIBARDOUR_API RawMidiParser
+{
+public:
+	RawMidiParser ();
+
+	void reset () {
+		_event_size = 0;
+		_unbuffered_bytes = 0;
+		_total_bytes = 0;
+		_expected_bytes = 0;
+		_status_byte = 0;
+	}
+
+	uint8_t const * midi_buffer () const { return  _parser_buffer; }
+	size_t buffer_size () const { return _event_size; }
+
+	/** parse a MIDI byte
+	 * @return true if message is complete, false if more data is needed
+	 */
+	bool process_byte (const uint8_t byte);
+
+private:
+
+	void record_byte (uint8_t byte) {
+		if (_total_bytes < sizeof (_parser_buffer)) {
+			_parser_buffer[_total_bytes] = byte;
+		} else {
+			++_unbuffered_bytes;
+		}
+		++_total_bytes;
+	}
+
+	void prepare_byte_event (const uint8_t byte) {
+		_parser_buffer[0] = byte;
+		_event_size = 1;
+	}
+
+	bool prepare_buffered_event () {
+		const bool result = _unbuffered_bytes == 0;
+		if (result) {
+			_event_size = _total_bytes;
+		}
+		_total_bytes = 0;
+		_unbuffered_bytes = 0;
+		if (_status_byte >= 0xf0) {
+			_expected_bytes = 0;
+			_status_byte = 0;
+		}
+		return result;
+	}
+
+	size_t  _event_size;
+	size_t  _unbuffered_bytes;
+	size_t  _total_bytes;
+	size_t  _expected_bytes;
+	uint8_t _status_byte;
+	uint8_t _parser_buffer[1024];
+};
+
+} // namespace ARDOUR
+
+#endif /* _ardour_raw_midi_parser_h_ */
diff --git a/libs/ardour/raw_midi_parser.cc b/libs/ardour/raw_midi_parser.cc
new file mode 100644
index 0000000000..273f792194
--- /dev/null
+++ b/libs/ardour/raw_midi_parser.cc
@@ -0,0 +1,118 @@
+/*
+ * Copyright (C) 2014,2017 Robin Gareus <robin@gareus.org>
+ * Copyright (C) 2010 Devin Anderson
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+#include "ardour/raw_midi_parser.h"
+
+using namespace ARDOUR;
+
+RawMidiParser::RawMidiParser ()
+{
+	reset ();
+}
+
+/* based on AlsaRawMidiIn, some code-dup */
+bool
+RawMidiParser::process_byte (const uint8_t byte)
+{
+	if (byte >= 0xf8) {
+		// Realtime
+		if (byte == 0xfd) {
+			return false;
+		}
+		prepare_byte_event (byte);
+		return true;
+	}
+	if (byte == 0xf7) {
+		// Sysex end
+		if (_status_byte == 0xf0) {
+			record_byte (byte);
+			return prepare_buffered_event ();
+		}
+		_total_bytes = 0;
+		_unbuffered_bytes = 0;
+		_expected_bytes = 0;
+		_status_byte = 0;
+		return false;
+	}
+	if (byte >= 0x80) {
+		// Non-realtime status byte
+		if (_total_bytes) {
+			_total_bytes = 0;
+			_unbuffered_bytes = 0;
+		}
+		_status_byte = byte;
+		switch (byte & 0xf0) {
+			case 0x80:
+			case 0x90:
+			case 0xa0:
+			case 0xb0:
+			case 0xe0:
+				// Note On, Note Off, Aftertouch, Control Change, Pitch Wheel
+				_expected_bytes = 3;
+				break;
+			case 0xc0:
+			case 0xd0:
+				// Program Change, Channel Pressure
+				_expected_bytes = 2;
+				break;
+			case 0xf0:
+				switch (byte) {
+					case 0xf0:
+						// Sysex
+						_expected_bytes = 0;
+						break;
+					case 0xf1:
+					case 0xf3:
+						// MTC Quarter Frame, Song Select
+						_expected_bytes = 2;
+						break;
+					case 0xf2:
+						// Song Position
+						_expected_bytes = 3;
+						break;
+					case 0xf4:
+					case 0xf5:
+						// Undefined
+						_expected_bytes = 0;
+						_status_byte = 0;
+						return false;
+					case 0xf6:
+						// Tune Request
+						prepare_byte_event (byte);
+						_expected_bytes = 0;
+						_status_byte = 0;
+						return true;
+				}
+		}
+		record_byte (byte);
+		return false;
+	}
+	// Data byte
+	if (!_status_byte) {
+		// Data bytes without a status will be discarded.
+		_total_bytes++;
+		_unbuffered_bytes++;
+		return false;
+	}
+	if (!_total_bytes) {
+		record_byte (_status_byte);
+	}
+	record_byte (byte);
+	return (_total_bytes == _expected_bytes) ? prepare_buffered_event () : false;
+}
diff --git a/libs/ardour/wscript b/libs/ardour/wscript
index 7a4a26c151..8cd06692bf 100644
--- a/libs/ardour/wscript
+++ b/libs/ardour/wscript
@@ -180,6 +180,7 @@ libardour_sources = [
         'quantize.cc',
         'rc_configuration.cc',
         'readonly_control.cc',
+        'raw_midi_parser.cc',
         'recent_sessions.cc',
         'record_enable_control.cc',
         'record_safe_control.cc',