OXYGENHUB
◆ main openmsx / src / serial / MidiOutDevice.cc
3.0 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
1 
#include "MidiOutDevice.hh"
2
3 
#include "unreachable.hh"
4
5 
namespace openmsx {
6
7 
static constexpr uint8_t MIDI_MSG_SYSEX     = 0xF0;
8 
static constexpr uint8_t MIDI_MSG_SYSEX_END = 0xF7;
9 
static constexpr uint8_t MIDI_MSG_RESET     = 0xFF;
10
11 
/** Returns the size in bytes of a message that starts with the given status.
12 
  */
13 
[[nodiscard]] static constexpr size_t midiMessageLength(uint8_t status)
14 
{
15 
	if (status < 0x80) {
16 
		assert(false);
17 
		return 0;
18 
	} else if (status < 0xC0) {
19 
		return 3;
20 
	} else if (status < 0xE0) {
21 
		return 2;
22 
	} else if (status < 0xF0) {
23 
		return 3;
24 
	} else {
25 
		switch (status) {
26 
		case MIDI_MSG_SYSEX:
27 
			// Limit to force sending large SysEx messages in chunks.
28 
			return MidiOutDevice::MAX_MESSAGE_SIZE;
29 
		case MIDI_MSG_SYSEX_END:
30 
			assert(false);
31 
			return 0;
32 
		case 0xF1:
33 
		case 0xF3:
34 
			return 2;
35 
		case 0xF2:
36 
			return 3;
37 
		case 0xF4:
38 
		case 0xF5:
39 
		case 0xF9:
40 
		case 0xFD:
41 
			// Data size unknown
42 
			return 1;
43 
		default:
44 
			return 1;
45 
		}
46 
	}
47 
}
48
49 
zstring_view MidiOutDevice::getClass() const
50 
{
51 
	return "midi out";
52 
}
53
54 
void MidiOutDevice::clearBuffer()
55 
{
56 
	buffer.clear();
57 
	isSysEx = false;
58 
}
59
60 
void MidiOutDevice::recvByte(uint8_t value, EmuTime time)
61 
{
62 
	if (value & 0x80) { // status byte
63 
		if (value == MIDI_MSG_SYSEX_END) {
64 
			if (isSysEx) {
65 
				buffer.push_back(value);
66 
				recvMessage(buffer, time);
67 
			} else {
68 
				// Ignoring SysEx end without start
69 
			}
70 
			buffer.clear();
71 
			isSysEx = false;
72 
		} else if (value >= 0xF8) {
73 
			// Realtime message, send immediately.
74 
			std::vector<uint8_t> realtimeMessage = { value };
75 
			recvMessage(realtimeMessage, time);
76 
			if (value == MIDI_MSG_RESET) {
77 
				buffer.clear();
78 
			}
79 
			return;
80 
		} else {
81 
			// Replace any message in progress.
82 
			if (isSysEx) {
83 
				// Discarding incomplete MIDI SysEx message
84 
			} else if (buffer.size() >= 2) {
85 
				#if 0
86 
				std::cerr << "Discarding incomplete MIDI message with status "
87 
				             "0x" << std::hex << int(buffer[0]) << std::dec <<
88 
				             ", at " << buffer.size() << " of " <<
89 
				             midiMessageLength(buffer[0]) << " bytes\n";
90 
				#endif
91 
			}
92 
			buffer = { value };
93 
			isSysEx = value == MIDI_MSG_SYSEX;
94 
		}
95 
	} else { // data byte
96 
		if (buffer.empty() && !isSysEx) {
97 
			// Ignoring MIDI data without preceding status
98 
		} else {
99 
			buffer.push_back(value);
100 
		}
101 
	}
102
103 
	// Is the message complete?
104 
	if (!buffer.empty()) {
105 
		uint8_t status = isSysEx ? MIDI_MSG_SYSEX : buffer[0];
106 
		size_t len = midiMessageLength(status);
107 
		if (buffer.size() >= len) {
108 
			recvMessage(buffer, time);
109 
			if (status >= 0xF0 && status < 0xF8) {
110 
				buffer.clear();
111 
			} else {
112 
				// Keep last status, to support running status.
113 
				buffer.resize(1);
114 
			}
115 
		}
116 
	}
117 
}
118
119 
void MidiOutDevice::recvMessage(
120 
		const std::vector<uint8_t>& /*message*/, EmuTime /*time*/)
121 
{
122 
	UNREACHABLE;
123 
}
124
125 
void MidiOutDevice::setDataBits(DataBits /*bits*/)
126 
{
127 
	// ignore
128 
}
129
130 
void MidiOutDevice::setStopBits(StopBits /*bits*/)
131 
{
132 
	// ignore
133 
}
134
135 
void MidiOutDevice::setParityBit(bool /*enable*/, Parity /*parity*/)
136 
{
137 
	// ignore
138 
}
139
140 
} // namespace openmsx