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Diffstat (limited to 'drumgizmo/input/alsamidi.cc')
| -rw-r--r-- | drumgizmo/input/alsamidi.cc | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/drumgizmo/input/alsamidi.cc b/drumgizmo/input/alsamidi.cc new file mode 100644 index 0000000..068ea2b --- /dev/null +++ b/drumgizmo/input/alsamidi.cc @@ -0,0 +1,196 @@ +/* -*- 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: The ALSA MIDI event structure does + // not seem to contain the raw MIDI data, therefore we have to re-create + // the raw MIDI data based on the ALSA sequence event information. + std::vector<uint8_t> midi_buffer(3, 0); + bool message_type_handled = true; + + switch(ev->type) + { + case SND_SEQ_EVENT_NOTEON: + midi_buffer[0] = ev->data.note.channel + 0x90; // NoteOn + midi_buffer[1] = ev->data.note.note; + midi_buffer[2] = ev->data.note.velocity; + break; + + case SND_SEQ_EVENT_NOTEOFF: + midi_buffer[0] = ev->data.note.channel + 0x80; // NoteOff + midi_buffer[1] = ev->data.note.note; + midi_buffer[2] = ev->data.note.off_velocity; + break; + + case SND_SEQ_EVENT_KEYPRESS: + midi_buffer[0] = ev->data.note.channel + 0xA0; // NoteAftertouch + midi_buffer[1] = ev->data.note.note; + midi_buffer[2] = ev->data.note.velocity; + break; + + case SND_SEQ_EVENT_CONTROLLER: + midi_buffer[0] = ev->data.control.channel + 0xB0; // ControlChange + midi_buffer[1] = ev->data.control.param; + midi_buffer[2] = ev->data.control.value; + break; + + default: + // unkown message type, ignore the message + message_type_handled = false; + break; + } + + if(message_type_handled) + { + // since we do not want to introduce any additional delay for the + // MIDI processing, we set the offset to zero + processNote(midi_buffer.data(), midi_buffer.size(), 0, events); + } + } + snd_seq_free_event(ev); +} + +void AlsaMidiInputEngine::post() +{ +} + +bool AlsaMidiInputEngine::isFreewheeling() const +{ + return true; +} |