boo/lib/audiodev/MIDIDecoder.cpp

193 lines
4.5 KiB
C++

#include "boo/audiodev/MIDIDecoder.hpp"
#include <algorithm>
#include <optional>
#include "boo/audiodev/IMIDIReader.hpp"
#include "lib/audiodev/MIDICommon.hpp"
namespace boo {
namespace {
constexpr uint8_t clamp7(uint8_t val) { return std::clamp(val, uint8_t{0}, uint8_t{127}); }
std::optional<uint32_t> readContinuedValue(std::vector<uint8_t>::const_iterator& it,
std::vector<uint8_t>::const_iterator end) {
uint8_t a = *it++;
uint32_t valOut = a & 0x7f;
if ((a & 0x80) != 0) {
if (it == end) {
return std::nullopt;
}
valOut <<= 7;
a = *it++;
valOut |= a & 0x7f;
if ((a & 0x80) != 0) {
if (it == end) {
return std::nullopt;
}
valOut <<= 7;
a = *it++;
valOut |= a & 0x7f;
}
}
return valOut;
}
} // Anonymous namespace
std::vector<uint8_t>::const_iterator MIDIDecoder::receiveBytes(std::vector<uint8_t>::const_iterator begin,
std::vector<uint8_t>::const_iterator end) {
auto it = begin;
while (it != end) {
uint8_t a = *it++;
uint8_t b;
if (a & 0x80)
m_status = a;
else
it--;
if (m_status == 0xff) {
/* Meta events (ignored for now) */
if (it == end)
return begin;
a = *it++;
const auto length = readContinuedValue(it, end);
it += *length;
} else {
uint8_t chan = m_status & 0xf;
switch (Status(m_status & 0xf0)) {
case Status::NoteOff: {
if (it == end)
return begin;
a = *it++;
if (it == end)
return begin;
b = *it++;
m_out.noteOff(chan, clamp7(a), clamp7(b));
break;
}
case Status::NoteOn: {
if (it == end)
return begin;
a = *it++;
if (it == end)
return begin;
b = *it++;
m_out.noteOn(chan, clamp7(a), clamp7(b));
break;
}
case Status::NotePressure: {
if (it == end)
return begin;
a = *it++;
if (it == end)
return begin;
b = *it++;
m_out.notePressure(chan, clamp7(a), clamp7(b));
break;
}
case Status::ControlChange: {
if (it == end)
return begin;
a = *it++;
if (it == end)
return begin;
b = *it++;
m_out.controlChange(chan, clamp7(a), clamp7(b));
break;
}
case Status::ProgramChange: {
if (it == end)
return begin;
a = *it++;
m_out.programChange(chan, clamp7(a));
break;
}
case Status::ChannelPressure: {
if (it == end)
return begin;
a = *it++;
m_out.channelPressure(chan, clamp7(a));
break;
}
case Status::PitchBend: {
if (it == end)
return begin;
a = *it++;
if (it == end)
return begin;
b = *it++;
m_out.pitchBend(chan, clamp7(b) * 128 + clamp7(a));
break;
}
case Status::SysEx: {
switch (Status(m_status & 0xff)) {
case Status::SysEx: {
const auto len = readContinuedValue(it, end);
if (!len || end - it < *len) {
return begin;
}
m_out.sysex(&*it, *len);
break;
}
case Status::TimecodeQuarterFrame: {
if (it == end)
return begin;
a = *it++;
m_out.timeCodeQuarterFrame(a >> 4 & 0x7, a & 0xf);
break;
}
case Status::SongPositionPointer: {
if (it == end)
return begin;
a = *it++;
if (it == end)
return begin;
b = *it++;
m_out.songPositionPointer(clamp7(b) * 128 + clamp7(a));
break;
}
case Status::SongSelect: {
if (it == end)
return begin;
a = *it++;
m_out.songSelect(clamp7(a));
break;
}
case Status::TuneRequest:
m_out.tuneRequest();
break;
case Status::Start:
m_out.startSeq();
break;
case Status::Continue:
m_out.continueSeq();
break;
case Status::Stop:
m_out.stopSeq();
break;
case Status::Reset:
m_out.reset();
break;
case Status::SysExTerm:
case Status::TimingClock:
case Status::ActiveSensing:
default:
break;
}
break;
}
default:
break;
}
}
}
return it;
}
} // namespace boo