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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/***************************************************************************
* alsamidi.cc
*
* Copyright 2021 Volker Fischer (github.com/corrados)
****************************************************************************/
/*
* This file is part of DrumGizmo.
*
* DrumGizmo 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 3 of the License, or
* (at your option) any later version.
*
* DrumGizmo 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 DrumGizmo; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*/
#include <iostream>
#include <cassert>
#include "cpp11fix.h" // required for c++11
#include "alsamidi.h"
struct AlsaMidiInitError
{
int const code;
const std::string msg;
AlsaMidiInitError(int op_code, const std::string& msg)
: code{op_code}
, msg{msg}
{
}
static inline void test(int code, const std::string& msg)
{
if(code < 0)
{
throw AlsaMidiInitError(code, msg);
}
}
};
AlsaMidiInputEngine::AlsaMidiInputEngine()
: AudioInputEngineMidi{}
, in_port(0)
, seq_handle{nullptr}
, pos{0u}
, events{}
{
}
AlsaMidiInputEngine::~AlsaMidiInputEngine()
{
if(seq_handle != nullptr)
{
snd_seq_close(seq_handle);
}
}
bool AlsaMidiInputEngine::init(const Instruments& instruments)
{
if(!loadMidiMap(midimap_file, instruments))
{
std::cerr << "[AlsaMidiInputEngine] Failed to parse midimap '"
<< midimap_file << "'\n";
return false;
}
// try to initialize alsa MIDI
try
{
// it is not allowed to block in the run() function, therefore we
// have to use a non-blocking mode
int value = snd_seq_open(&seq_handle, "default",
SND_SEQ_OPEN_INPUT, SND_SEQ_NONBLOCK);
AlsaMidiInitError::test(value, "snd_seq_open");
value = snd_seq_set_client_name(seq_handle, "drumgizmo");
AlsaMidiInitError::test(value, "snd_seq_set_client_name");
in_port =
snd_seq_create_simple_port(seq_handle, "listen:in",
SND_SEQ_PORT_CAP_WRITE |
SND_SEQ_PORT_CAP_SUBS_WRITE,
SND_SEQ_PORT_TYPE_APPLICATION);
AlsaMidiInitError::test(in_port, "snd_seq_create_simple_port");
}
catch(AlsaMidiInitError const& error)
{
std::cerr << "[AlsaMidiInputEngine] " << error.msg
<< " failed: " << snd_strerror(error.code) << std::endl;
return false;
}
return true;
}
void AlsaMidiInputEngine::setParm(const std::string& parm,
const std::string& value)
{
if(parm == "midimap")
{
// apply midimap filename
midimap_file = value;
}
else
{
std::cerr << "[AlsaMidiInputEngine] Unsupported parameter '" << parm
<< "'\n";
}
}
bool AlsaMidiInputEngine::start()
{
return true;
}
void AlsaMidiInputEngine::stop()
{
}
void AlsaMidiInputEngine::pre()
{
}
void AlsaMidiInputEngine::run(size_t pos, size_t len,
std::vector<event_t>& events)
{
assert(events.empty());
snd_seq_event_t* ev = NULL;
if ( snd_seq_event_input(seq_handle, &ev) >= 0 )
{
// TODO Better solution needed: It seems that the very first raw byte
// of the MIDI message is missing the type information which is coded
// in the 4 high bits of the first byte. As a quick hack we add this
// information based on the type information of the sequence event.
std::uint8_t myd[3];
for ( int i = 0; i < 3; ++i)
{
myd[i] = ev->data.raw8.d[i];
}
if(ev->type == SND_SEQ_EVENT_NOTEON)
{
myd[0] += 0x90; // NoteOn
}
else if(ev->type == SND_SEQ_EVENT_NOTEOFF)
{
myd[0] += 0x80; // NoteOff
}
else if(ev->type == SND_SEQ_EVENT_KEYPRESS )
{
myd[0] += 0xA0; // NoteAftertouch
}
// since we do not want to introduce any additional delay for the
// MIDI processing, we set the offset to zero
processNote(myd, 3, 0, events);
}
snd_seq_free_event(ev);
}
void AlsaMidiInputEngine::post()
{
}
bool AlsaMidiInputEngine::isFreewheeling() const
{
return true;
}
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