scummvm/audio/softsynth/mt32/MidiStreamParser.h

/* Copyright (C) 2003, 2004, 2005, 2006, 2008, 2009 Dean Beeler, Jerome Fisher
 * Copyright (C) 2011-2021 Dean Beeler, Jerome Fisher, Sergey V. Mikayev
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as published by
 *  the Free Software Foundation, either version 2.1 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 Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef MT32EMU_MIDI_STREAM_PARSER_H
#define MT32EMU_MIDI_STREAM_PARSER_H

#include "globals.h"
#include "Types.h"

namespace MT32Emu {

class Synth;

// Interface for a user-supplied class to receive parsed well-formed MIDI messages.
class MT32EMU_EXPORT MidiReceiver {
public:
	// Invoked when a complete short MIDI message is parsed in the input MIDI stream.
	virtual void handleShortMessage(const Bit32u message) = 0;

	// Invoked when a complete well-formed System Exclusive MIDI message is parsed in the input MIDI stream.
	virtual void handleSysex(const Bit8u stream[], const Bit32u length) = 0;

	// Invoked when a System Realtime MIDI message is parsed in the input MIDI stream.
	virtual void handleSystemRealtimeMessage(const Bit8u realtime) = 0;

protected:
	~MidiReceiver() {}
};

// Interface for a user-supplied class to receive notifications of input MIDI stream parse errors.
class MT32EMU_EXPORT MidiReporter {
public:
	// Invoked when an error occurs during processing the input MIDI stream.
	virtual void printDebug(const char *debugMessage) = 0;

protected:
	~MidiReporter() {}
};

// Provides a context for parsing a stream of MIDI events coming from a single source.
// There can be multiple MIDI sources feeding MIDI events to a single Synth object.
// NOTE: Calls from multiple threads which feed a single Synth object with data must be explicitly synchronised,
// although, no synchronisation is required with the rendering thread.
class MT32EMU_EXPORT MidiStreamParserImpl {
public:
	// The first two arguments provide for implementations of essential interfaces needed.
	// The third argument specifies streamBuffer initial capacity. The buffer capacity should be large enough to fit the longest SysEx expected.
	// If a longer SysEx occurs, streamBuffer is reallocated to the maximum size of MAX_STREAM_BUFFER_SIZE (32768 bytes).
	// Default capacity is SYSEX_BUFFER_SIZE (1000 bytes) which is enough to fit SysEx messages in common use.
	MidiStreamParserImpl(MidiReceiver &, MidiReporter &, Bit32u initialStreamBufferCapacity = SYSEX_BUFFER_SIZE);
	virtual ~MidiStreamParserImpl();

	// Parses a block of raw MIDI bytes. All the parsed MIDI messages are sent in sequence to the user-supplied methods for further processing.
	// SysEx messages are allowed to be fragmented across several calls to this method. Running status is also handled for short messages.
	// NOTE: the total length of a SysEx message being fragmented shall not exceed MAX_STREAM_BUFFER_SIZE (32768 bytes).
	void parseStream(const Bit8u *stream, Bit32u length);

	// Convenience method which accepts a Bit32u-encoded short MIDI message and sends it to the user-supplied method for further processing.
	// The short MIDI message may contain no status byte, the running status is used in this case.
	void processShortMessage(const Bit32u message);

private:
	Bit8u runningStatus;
	Bit8u *streamBuffer;
	Bit32u streamBufferCapacity;
	Bit32u streamBufferSize;
	MidiReceiver &midiReceiver;
	MidiReporter &midiReporter;

	// Binary compatibility helper.
	void *reserved;

	bool checkStreamBufferCapacity(const bool preserveContent);
	bool processStatusByte(Bit8u &status);
	Bit32u parseShortMessageStatus(const Bit8u stream[]);
	Bit32u parseShortMessageDataBytes(const Bit8u stream[], Bit32u length);
	Bit32u parseSysex(const Bit8u stream[], const Bit32u length);
	Bit32u parseSysexFragment(const Bit8u stream[], const Bit32u length);
}; // class MidiStreamParserImpl

// An abstract class that provides a context for parsing a stream of MIDI events coming from a single source.
class MT32EMU_EXPORT MidiStreamParser : public MidiStreamParserImpl, protected MidiReceiver, protected MidiReporter {
public:
	// The argument specifies streamBuffer initial capacity. The buffer capacity should be large enough to fit the longest SysEx expected.
	// If a longer SysEx occurs, streamBuffer is reallocated to the maximum size of MAX_STREAM_BUFFER_SIZE (32768 bytes).
	// Default capacity is SYSEX_BUFFER_SIZE (1000 bytes) which is enough to fit SysEx messages in common use.
	explicit MidiStreamParser(Bit32u initialStreamBufferCapacity = SYSEX_BUFFER_SIZE);
};

class MT32EMU_EXPORT DefaultMidiStreamParser : public MidiStreamParser {
public:
	explicit DefaultMidiStreamParser(Synth &synth, Bit32u initialStreamBufferCapacity = SYSEX_BUFFER_SIZE);
	void setTimestamp(const Bit32u useTimestamp);
	void resetTimestamp();

protected:
	void handleShortMessage(const Bit32u message);
	void handleSysex(const Bit8u *stream, const Bit32u length);
	void handleSystemRealtimeMessage(const Bit8u realtime);
	void printDebug(const char *debugMessage);

private:
	Synth &synth;
	bool timestampSet;
	Bit32u timestamp;
};

} // namespace MT32Emu

#endif // MT32EMU_MIDI_STREAM_PARSER_H