godot/core/os/midi_driver.h
Ibrahn Sahir 607c5ec49f Move MIDI parsing up from ALSA driver to platform independent driver.
Aims for more consistent MIDI support across Windows, MacOS, Linux and
to provide a base for adding MIDI drivers for other platforms.
Reworks the MIDIDriverALSAMidi MIDI parsing implementation as a platform
independent version in MIDIDriver::Parser.
Uses MIDIDriver::Parser to provide running status support in MacOS
MIDIDriverCoreMidi.
Collects connected input names at open, ensuring devices indices reported
in events match names in array returned from get_connected_inputs.

Fixes #77035.
Fixes #79811.

With code review changes by: A Thousand Ships (she/her)
<96648715+AThousandShips@users.noreply.github.com>
2024-06-25 16:46:30 +01:00

115 lines
4.4 KiB
C++

/**************************************************************************/
/* midi_driver.h */
/**************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/**************************************************************************/
/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
/* */
/* 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, */
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/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions: */
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/* The above copyright notice and this permission notice shall be */
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/**************************************************************************/
#ifndef MIDI_DRIVER_H
#define MIDI_DRIVER_H
#include "core/typedefs.h"
#include "core/variant/variant.h"
/**
* Multi-Platform abstraction for accessing to MIDI.
*/
class MIDIDriver {
static MIDIDriver *singleton;
static uint8_t last_received_message;
protected:
// Categories of message for parser logic.
enum class MessageCategory {
Data,
Voice,
SysExBegin,
SystemCommon, // excluding System Exclusive Begin/End
SysExEnd,
RealTime,
};
// Convert midi data to InputEventMIDI and send it to Input.
// p_data_len is the length of the buffer passed at p_data, this must be
// at least equal to the data required by the passed message type, but
// may be larger. Only the required data will be read.
static void send_event(int p_device_index, uint8_t p_status,
const uint8_t *p_data = nullptr, size_t p_data_len = 0);
class Parser {
public:
Parser() = default;
Parser(int p_device_index) :
device_index{ p_device_index } {}
virtual ~Parser() = default;
// Push a byte of MIDI stream. Any completed messages will be
// forwarded to MIDIDriver::send_event.
void parse_fragment(uint8_t p_fragment);
static MessageCategory category(uint8_t p_midi_fragment);
// If the byte is a Voice Message status byte return the contained
// channel number, otherwise zero.
static uint8_t channel(uint8_t p_status_byte);
// If the byte is a status byte for a message with a fixed number of
// additional data bytes, return the number expected, otherwise zero.
static size_t expected_data(uint8_t p_status_byte);
static size_t expected_data(MIDIMessage p_msg_type);
// If the fragment is a status byte return the message type
// represented, otherwise MIDIMessage::NONE.
static MIDIMessage status_to_msg_enum(uint8_t p_status_byte);
private:
int device_index = 0;
static constexpr size_t DATA_BUFFER_SIZE = 2;
uint8_t status_byte = 0;
uint8_t data_buffer[DATA_BUFFER_SIZE] = { 0 };
size_t received_data_len = 0;
bool skipping_sys_ex = false;
};
PackedStringArray connected_input_names;
public:
static MIDIDriver *get_singleton();
MIDIDriver();
virtual ~MIDIDriver() = default;
virtual Error open() = 0;
virtual void close() = 0;
PackedStringArray get_connected_inputs() const;
};
#endif // MIDI_DRIVER_H