Merge 7edc18c977 into bd2430dc94

CMakeLists.txt

@@ -144,6 +144,7 @@ if(NOT OPTION_DEDICATED)
             find_package(Freetype)
             find_package(SDL2)
             find_package(Fluidsynth)
+            find_package(ALSA)
             if(Freetype_FOUND)
                 find_package(Fontconfig)
             endif()
@@ -326,6 +327,7 @@ if(NOT OPTION_DEDICATED)
     link_package(ICU_i18n)
     link_package(ICU_uc)
     link_package(OpusFile TARGET OpusFile::opusfile)
+    link_package(ALSA)
 
     if(SDL2_FOUND AND OPENGL_FOUND AND UNIX)
         # SDL2 dynamically loads OpenGL if needed, so do not link to OpenGL when

cmake/FindALSA.cmake

@@ -0,0 +1,76 @@
+#[=======================================================================[.rst:
+FindALSA
+--------
+
+Find Advanced Linux Sound Architecture (ALSA)
+
+Find the alsa libraries (``asound``)
+
+IMPORTED Targets
+^^^^^^^^^^^^^^^^
+
+.. versionadded:: 3.12
+
+This module defines :prop_tgt:`IMPORTED` target ``ALSA::ALSA``, if
+ALSA has been found.
+
+Result Variables
+^^^^^^^^^^^^^^^^
+
+This module defines the following variables:
+
+``ALSA_FOUND``
+  True if ALSA_INCLUDE_DIR & ALSA_LIBRARY are found
+
+``ALSA_LIBRARIES``
+  List of libraries when using ALSA.
+
+``ALSA_INCLUDE_DIRS``
+  Where to find the ALSA headers.
+
+Cache variables
+^^^^^^^^^^^^^^^
+
+The following cache variables may also be set:
+
+``ALSA_INCLUDE_DIR``
+  the ALSA include directory
+
+``ALSA_LIBRARY``
+  the absolute path of the asound library
+#]=======================================================================]
+
+find_package(PkgConfig QUIET)
+pkg_check_modules(PC_ALSA QUIET alsa)
+
+find_path(ALSA_INCLUDE_DIR NAMES alsa/asoundlib.h
+          DOC "The ALSA (asound) include directory"
+)
+
+find_library(ALSA_LIBRARY NAMES asound
+          DOC "The ALSA (asound) library"
+)
+
+if(ALSA_INCLUDE_DIR AND EXISTS "${ALSA_INCLUDE_DIR}/alsa/version.h")
+  file(STRINGS "${ALSA_INCLUDE_DIR}/alsa/version.h" alsa_version_str REGEX "^#define[\t ]+SND_LIB_VERSION_STR[\t ]+\".*\"")
+
+  string(REGEX REPLACE "^.*SND_LIB_VERSION_STR[\t ]+\"([^\"]*)\".*$" "\\1" ALSA_VERSION_STRING "${alsa_version_str}")
+  unset(alsa_version_str)
+endif()
+
+include(FindPackageHandleStandardArgs)
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(ALSA
+                                  REQUIRED_VARS ALSA_LIBRARY ALSA_INCLUDE_DIR
+                                  VERSION_VAR ALSA_VERSION_STRING)
+
+if(ALSA_FOUND)
+  set( ALSA_LIBRARIES ${ALSA_LIBRARY} )
+  set( ALSA_INCLUDE_DIRS ${ALSA_INCLUDE_DIR} )
+  if(NOT TARGET ALSA::ALSA)
+    add_library(ALSA::ALSA UNKNOWN IMPORTED)
+    set_target_properties(ALSA::ALSA PROPERTIES INTERFACE_INCLUDE_DIRECTORIES "${ALSA_INCLUDE_DIRS}")
+    set_property(TARGET ALSA::ALSA APPEND PROPERTY IMPORTED_LOCATION "${ALSA_LIBRARY}")
+  endif()
+endif()
+
+mark_as_advanced(ALSA_INCLUDE_DIR ALSA_LIBRARY)

src/3rdparty/CMakeLists.txt

@@ -7,3 +7,4 @@ add_subdirectory(squirrel)
 add_subdirectory(nlohmann)
 add_subdirectory(opengl)
 add_subdirectory(openttd_social_integration_api)
+add_subdirectory(midifile)

src/3rdparty/midifile/Binasc.h

@@ -0,0 +1,161 @@
+//
+// Programmer:    Craig Stuart Sapp <craig@ccrma.stanford.edu>
+// Creation Date: Mon Feb 16 12:26:32 PST 2015 Adapted from binasc program.
+// Last Modified: Sat Apr 21 10:52:19 PDT 2018 Removed using namespace std;
+// Filename:      midifile/include/Binasc.h
+// Website:       http://midifile.sapp.org
+// Syntax:        C++11
+// vim:           ts=3 noexpandtab
+//
+// description:   Interface to convert bytes between binary and ASCII forms.
+//
+
+#ifndef _BINASC_H_INCLUDED
+#define _BINASC_H_INCLUDED
+
+#include <cstdlib>
+#include <fstream>
+#include <iostream>
+#include <string>
+
+
+namespace smf {
+
+typedef unsigned char uchar;
+typedef unsigned short ushort;
+typedef unsigned long ulong;
+
+class Binasc {
+
+	public:
+		                     Binasc                  (void);
+
+		                    ~Binasc                  ();
+
+		// functions for setting options:
+		int                  setLineLength           (int length);
+		int                  getLineLength           (void);
+		int                  setLineBytes            (int length);
+		int                  getLineBytes            (void);
+		void                 setComments             (int state);
+		void                 setCommentsOn           (void);
+		void                 setCommentsOff          (void);
+		int                  getComments             (void);
+		void                 setBytes                (int state);
+		void                 setBytesOn              (void);
+		void                 setBytesOff             (void);
+		int                  getBytes                (void);
+		void                 setMidi                 (int state);
+		void                 setMidiOn               (void);
+		void                 setMidiOff              (void);
+		int                  getMidi                 (void);
+
+		// functions for converting into a binary file:
+		int                  writeToBinary           (const std::string& outfile,
+		                                              const std::string& infile);
+		int                  writeToBinary           (const std::string& outfile,
+		                                              std::istream& input);
+		int                  writeToBinary           (std::ostream& out,
+		                                              const std::string& infile);
+		int                  writeToBinary           (std::ostream& out,
+		                                              std::istream& input);
+
+		// functions for converting into an ASCII file with hex bytes:
+		int                  readFromBinary          (const std::string&
+		                                              outfile,
+		                                              const std::string& infile);
+		int                  readFromBinary          (const std::string& outfile,
+		                                              std::istream& input);
+		int                  readFromBinary          (std::ostream& out,
+		                                              const std::string& infile);
+		int                  readFromBinary          (std::ostream& out,
+		                                              std::istream& input);
+
+		// static functions for writing ordered bytes:
+		static std::ostream& writeLittleEndianUShort (std::ostream& out,
+		                                              ushort value);
+		static std::ostream& writeBigEndianUShort    (std::ostream& out,
+		                                              ushort value);
+		static std::ostream& writeLittleEndianShort  (std::ostream& out,
+		                                              short value);
+		static std::ostream& writeBigEndianShort     (std::ostream& out,
+		                                              short value);
+		static std::ostream& writeLittleEndianULong  (std::ostream& out,
+		                                              ulong value);
+		static std::ostream& writeBigEndianULong     (std::ostream& out,
+		                                              ulong value);
+		static std::ostream& writeLittleEndianLong   (std::ostream& out,
+		                                              long value);
+		static std::ostream& writeBigEndianLong      (std::ostream& out,
+		                                              long value);
+		static std::ostream& writeLittleEndianFloat  (std::ostream& out,
+		                                              float value);
+		static std::ostream& writeBigEndianFloat     (std::ostream& out,
+		                                              float value);
+		static std::ostream& writeLittleEndianDouble (std::ostream& out,
+		                                              double value);
+		static std::ostream& writeBigEndianDouble    (std::ostream& out,
+		                                              double value);
+
+		static std::string   keyToPitchName          (int key);
+
+	protected:
+		int m_bytesQ;       // option for printing hex bytes in ASCII output.
+		int m_commentsQ;    // option for printing comments in ASCII output.
+		int m_midiQ;        // output ASCII data as parsed MIDI file.
+		int m_maxLineLength;// number of character in ASCII output on a line.
+		int m_maxLineBytes; // number of hex bytes in ASCII output on a line.
+
+	private:
+		// helper functions for reading ASCII content to conver to binary:
+		int                  processLine             (std::ostream& out,
+		                                              const std::string& input,
+		                                              int lineNum);
+		int                  processAsciiWord        (std::ostream& out,
+		                                              const std::string& input,
+		                                              int lineNum);
+		int                  processStringWord       (std::ostream& out,
+		                                              const std::string& input,
+		                                              int lineNum);
+		int                  processBinaryWord       (std::ostream& out,
+		                                              const std::string& input,
+		                                              int lineNum);
+		int                  processDecimalWord      (std::ostream& out,
+		                                              const std::string& input,
+		                                              int lineNum);
+		int                  processHexWord          (std::ostream& out,
+		                                              const std::string& input,
+		                                              int lineNum);
+		int                  processVlvWord          (std::ostream& out,
+		                                              const std::string& input,
+		                                              int lineNum);
+		int                  processMidiPitchBendWord(std::ostream& out,
+		                                              const std::string& input,
+		                                              int lineNum);
+		int                  processMidiTempoWord    (std::ostream& out,
+		                                              const std::string& input,
+		                                              int lineNum);
+
+		// helper functions for reading binary content to convert to ASCII:
+		int  outputStyleAscii   (std::ostream& out, std::istream& input);
+		int  outputStyleBinary  (std::ostream& out, std::istream& input);
+		int  outputStyleBoth    (std::ostream& out, std::istream& input);
+		int  outputStyleMidi    (std::ostream& out, std::istream& input);
+
+		// MIDI parsing helper functions:
+		int  readMidiEvent  (std::ostream& out, std::istream& infile,
+		                     int& trackbytes, int& command);
+		int  getVLV         (std::istream& infile, int& trackbytes);
+		int  getWord        (std::string& word, const std::string& input,
+		                     const std::string& terminators, int index);
+
+		static const char *GMinstrument[128];
+
+};
+
+} // end of namespace smf
+
+#endif /* _BINASC_H_INCLUDED */
+
+
+

src/3rdparty/midifile/CMakeLists.txt

@@ -0,0 +1,12 @@
+add_files(
+    Binasc.cpp
+    Binasc.h
+    MidiEvent.cpp
+    MidiEvent.h
+    MidiEventList.cpp
+    MidiEventList.h
+    MidiFile.cpp
+    MidiFile.h
+    MidiMessage.cpp
+    MidiMessage.h
+)

src/3rdparty/midifile/LICENSE.txt

@@ -0,0 +1,22 @@
+Copyright (c) 1999-2018, Craig Stuart Sapp
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
+2. Redistributions in binary form must reproduce the above copyright notice,
+   and the following disclaimer in the documentation and/or other materials
+   provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

src/3rdparty/midifile/MidiEvent.cpp

@@ -0,0 +1,298 @@
+//
+// Programmer:    Craig Stuart Sapp <craig@ccrma.stanford.edu>
+// Creation Date: Sat Feb 14 21:40:14 PST 2015
+// Last Modified: Sat Apr 21 10:52:19 PDT 2018 Removed using namespace std;
+// Filename:      midifile/src/MidiEvent.cpp
+// Website:       http://midifile.sapp.org
+// Syntax:        C++11
+// vim:           ts=3 noexpandtab
+//
+// Description:   A class which stores a MidiMessage and a timestamp
+//                for the MidiFile class.
+//
+
+#include "MidiEvent.h"
+
+#include <cstdlib>
+
+
+namespace smf {
+
+//////////////////////////////
+//
+// MidiEvent::MidiEvent -- Constructor classes
+//
+
+MidiEvent::MidiEvent(void) : MidiMessage() {
+	clearVariables();
+}
+
+
+MidiEvent::MidiEvent(int command) : MidiMessage(command)  {
+	clearVariables();
+}
+
+
+MidiEvent::MidiEvent(int command, int p1) : MidiMessage(command, p1) {
+	clearVariables();
+}
+
+
+MidiEvent::MidiEvent(int command, int p1, int p2)
+		: MidiMessage(command, p1, p2) {
+	clearVariables();
+}
+
+
+MidiEvent::MidiEvent(int aTime, int aTrack, vector<uchar>& message)
+		: MidiMessage(message) {
+	track       = aTrack;
+	tick        = aTime;
+	seconds     = 0.0;
+	seq         = 0;
+	m_eventlink = NULL;
+}
+
+
+MidiEvent::MidiEvent(const MidiEvent& mfevent) : MidiMessage() {
+	track   = mfevent.track;
+	tick    = mfevent.tick;
+	seconds = mfevent.seconds;
+	seq     = mfevent.seq;
+	m_eventlink = NULL;
+
+	this->resize(mfevent.size());
+	for (int i=0; i<(int)this->size(); i++) {
+		(*this)[i] = mfevent[i];
+	}
+}
+
+
+
+//////////////////////////////
+//
+// MidiEvent::~MidiEvent -- MidiFile Event destructor
+//
+
+MidiEvent::~MidiEvent() {
+	track   = -1;
+	tick    = -1;
+	seconds = -1.0;
+	seq     = -1;
+	this->resize(0);
+	m_eventlink = NULL;
+}
+
+
+//////////////////////////////
+//
+// MidiEvent::clearVariables --  Clear everything except MidiMessage data.
+//
+
+void MidiEvent::clearVariables(void) {
+	track     = 0;
+	tick      = 0;
+	seconds   = 0.0;
+	seq       = 0;
+	m_eventlink = NULL;
+}
+
+
+//////////////////////////////
+//
+// MidiEvent::operator= -- Copy the contents of another MidiEvent.
+//
+
+MidiEvent& MidiEvent::operator=(const MidiEvent& mfevent) {
+	if (this == &mfevent) {
+		return *this;
+	}
+	tick    = mfevent.tick;
+	track   = mfevent.track;
+	seconds = mfevent.seconds;
+	seq     = mfevent.seq;
+	m_eventlink = NULL;
+	this->resize(mfevent.size());
+	for (int i=0; i<(int)this->size(); i++) {
+		(*this)[i] = mfevent[i];
+	}
+	return *this;
+}
+
+
+MidiEvent& MidiEvent::operator=(const MidiMessage& message) {
+	if (this == &message) {
+		return *this;
+	}
+	clearVariables();
+	this->resize(message.size());
+	for (int i=0; i<(int)this->size(); i++) {
+		(*this)[i] = message[i];
+	}
+	return *this;
+}
+
+
+MidiEvent& MidiEvent::operator=(const vector<uchar>& bytes) {
+	clearVariables();
+	this->resize(bytes.size());
+	for (int i=0; i<(int)this->size(); i++) {
+		(*this)[i] = bytes[i];
+	}
+	return *this;
+}
+
+
+MidiEvent& MidiEvent::operator=(const vector<char>& bytes) {
+	clearVariables();
+	setMessage(bytes);
+	return *this;
+}
+
+
+MidiEvent& MidiEvent::operator=(const vector<int>& bytes) {
+	clearVariables();
+	setMessage(bytes);
+	return *this;
+}
+
+
+
+//////////////////////////////
+//
+// MidiEvent::unlinkEvent -- Disassociate this event with another.
+//   Also tell the other event to disassociate from this event.
+//
+
+void MidiEvent::unlinkEvent(void) {
+	if (m_eventlink == NULL) {
+		return;
+	}
+	MidiEvent* mev = m_eventlink;
+	m_eventlink = NULL;
+	mev->unlinkEvent();
+}
+
+
+
+//////////////////////////////
+//
+// MidiEvent::linkEvent -- Make a link between two messages.
+//   Unlinking
+//
+
+void MidiEvent::linkEvent(MidiEvent* mev) {
+	if (mev->m_eventlink != NULL) {
+		// unlink other event if it is linked to something else;
+		mev->unlinkEvent();
+	}
+	// if this is already linked to something else, then unlink:
+	if (m_eventlink != NULL) {
+		m_eventlink->unlinkEvent();
+	}
+	unlinkEvent();
+
+	mev->m_eventlink = this;
+	m_eventlink = mev;
+}
+
+
+void MidiEvent::linkEvent(MidiEvent& mev) {
+	linkEvent(&mev);
+}
+
+
+
+//////////////////////////////
+//
+// MidiEvent::getLinkedEvent -- Returns a linked event.  Usually
+//   this is the note-off message for a note-on message and vice-versa.
+//   Returns null if there are no links.
+//
+
+MidiEvent* MidiEvent::getLinkedEvent(void) {
+	return m_eventlink;
+}
+
+
+const MidiEvent* MidiEvent::getLinkedEvent(void) const {
+	return m_eventlink;
+}
+
+
+
+//////////////////////////////
+//
+// MidiEvent::isLinked -- Returns true if there is an event which is not
+//   NULL.  This function is similar to getLinkedEvent().
+//
+
+int MidiEvent::isLinked(void) const {
+	return m_eventlink == NULL ? 0 : 1;
+}
+
+
+
+//////////////////////////////
+//
+// MidiEvent::getTickDuration --  For linked events (note-ons and note-offs),
+//    return the absolute tick time difference between the two events.
+//    The tick values are presumed to be in absolute tick mode rather than
+//    delta tick mode.  Returns 0 if not linked.
+//
+
+int MidiEvent::getTickDuration(void) const {
+	const MidiEvent* mev = getLinkedEvent();
+	if (mev == NULL) {
+		return 0;
+	}
+	int tick2 = mev->tick;
+	if (tick2 > tick) {
+		return tick2 - tick;
+	} else {
+		return tick - tick2;
+	}
+}
+
+
+
+//////////////////////////////
+//
+// MidiEvent::getDurationInSeconds -- For linked events (note-ons and
+//     note-offs), return the duration of the note in seconds.  The
+//     seconds analysis must be done first; otherwise the duration will be
+//     reported as zero.
+//
+
+double MidiEvent::getDurationInSeconds(void) const {
+	const MidiEvent* mev = getLinkedEvent();
+	if (mev == NULL) {
+		return 0;
+	}
+	double seconds2 = mev->seconds;
+	if (seconds2 > seconds) {
+		return seconds2 - seconds;
+	} else {
+		return seconds - seconds2;
+	}
+}
+
+
+
+//////////////////////////////
+//
+// operator<<(MidiMessage) -- Print tick value followed by MIDI bytes for event.
+//     The tick value will be either relative or absolute depending on the state
+//     of the MidiFile object containing it.
+//
+
+std::ostream& operator<<(std::ostream& out, MidiEvent& event) {
+	out << event.tick << '(' << static_cast<MidiMessage&>(event) << ')';
+	return out;
+}
+
+
+} // end namespace smf
+
+
+

src/3rdparty/midifile/MidiEvent.h

@@ -0,0 +1,78 @@
+//
+// Programmer:    Craig Stuart Sapp <craig@ccrma.stanford.edu>
+// Creation Date: Sat Feb 14 21:47:39 PST 2015
+// Last Modified: Sat Apr 21 10:52:19 PDT 2018 Removed using namespace std;
+// Filename:      midifile/include/MidiEvent.h
+// Website:       http://midifile.sapp.org
+// Syntax:        C++11
+// vim:           ts=3 noexpandtab
+//
+// Description:   A class which stores a MidiMessage and a timestamp
+//                for the MidiFile class.
+//
+
+#ifndef _MIDIEVENT_H_INCLUDED
+#define _MIDIEVENT_H_INCLUDED
+
+#include "MidiMessage.h"
+
+#include <ostream>
+#include <vector>
+
+
+namespace smf {
+
+class MidiEvent : public MidiMessage {
+	public:
+		           MidiEvent             (void);
+		           MidiEvent             (int command);
+		           MidiEvent             (int command, int param1);
+		           MidiEvent             (int command, int param1, int param2);
+		           MidiEvent             (const MidiMessage& message);
+		           MidiEvent             (const MidiEvent& mfevent);
+		           MidiEvent             (int aTime, int aTrack,
+		                                  std::vector<uchar>& message);
+
+		          ~MidiEvent             ();
+
+		MidiEvent& operator=             (const MidiEvent& mfevent);
+		MidiEvent& operator=             (const MidiMessage& message);
+		MidiEvent& operator=             (const std::vector<uchar>& bytes);
+		MidiEvent& operator=             (const std::vector<char>& bytes);
+		MidiEvent& operator=             (const std::vector<int>& bytes);
+
+		void       clearVariables        (void);
+
+		// functions related to event linking (note-ons to note-offs).
+		void       unlinkEvent           (void);
+		void       unlinkEvents          (void);
+		void       linkEvent             (MidiEvent* mev);
+		void       linkEvents            (MidiEvent* mev);
+		void       linkEvent             (MidiEvent& mev);
+		void       linkEvents            (MidiEvent& mev);
+		int        isLinked              (void) const;
+		MidiEvent* getLinkedEvent        (void);
+		const MidiEvent* getLinkedEvent  (void) const;
+		int        getTickDuration       (void) const;
+		double     getDurationInSeconds  (void) const;
+
+		int        tick;     // delta or absolute MIDI ticks
+		int        track;    // [original] track number of event in MIDI file
+		double     seconds;  // calculated time in sec. (after doTimeAnalysis())
+		int        seq;      // sorting sequence number of event
+
+	private:
+		MidiEvent* m_eventlink;  // used to match note-ons and note-offs
+
+};
+
+
+std::ostream& operator<<(std::ostream& out, MidiEvent& event);
+
+
+} // end of namespace smf
+
+#endif /* _MIDIEVENT_H_INCLUDED */
+
+
+

src/3rdparty/midifile/MidiEventList.cpp

@@ -0,0 +1,623 @@
+//
+// Programmer:    Craig Stuart Sapp <craig@ccrma.stanford.edu>
+// Creation Date: Sat Feb 14 21:55:38 PST 2015
+// Last Modified: Sat Apr 21 10:52:19 PDT 2018 Removed using namespace std;
+// Filename:      midifile/src/MidiEventList.cpp
+// Website:       http://midifile.sapp.org
+// Syntax:        C++11
+// vim:           ts=3 noexpandtab
+//
+// Description:   A class which stores a MidiEvents for a MidiFile track.
+//
+
+#include "MidiEventList.h"
+
+#include <algorithm>
+#include <cstdlib>
+#include <iterator>
+#include <utility>
+#include <vector>
+
+
+namespace smf {
+
+//////////////////////////////
+//
+// MidiEventList::MidiEventList -- Constructor.
+//
+
+MidiEventList::MidiEventList(void) {
+	reserve(1000);
+}
+
+
+
+//////////////////////////////
+//
+// MidiEventList::MidiEventList(MidiEventList&) -- Copy constructor.
+//
+
+MidiEventList::MidiEventList(const MidiEventList& other) {
+	list.reserve(other.list.size());
+	auto it = other.list.begin();
+	std::generate_n(std::back_inserter(list), other.list.size(), [&]() -> MidiEvent* {
+		return new MidiEvent(**it++);
+	});
+}
+
+
+
+//////////////////////////////
+//
+// MidiEventList::MidiEventList(MidiEventList&&) -- Move constructor.
+//
+
+MidiEventList::MidiEventList(MidiEventList&& other) {
+	list = std::move(other.list);
+	other.list.clear();
+}
+
+
+
+//////////////////////////////
+//
+// MidiEventList::~MidiEventList -- Deconstructor.  Deallocate all stored
+//   data.
+//
+
+MidiEventList::~MidiEventList() {
+	clear();
+}
+
+
+
+//////////////////////////////
+//
+// MidiEventList::operator[] --
+//
+
+MidiEvent&  MidiEventList::operator[](int index) {
+	return *list[index];
+}
+
+
+const MidiEvent&  MidiEventList::operator[](int index) const {
+	return *list[index];
+}
+
+
+
+//////////////////////////////
+//
+// MidiEventList::back -- Return the last element in the list.
+//
+
+MidiEvent& MidiEventList::back(void) {
+	return *list.back();
+}
+
+
+const MidiEvent& MidiEventList::back(void) const {
+	return *list.back();
+}
+
+//
+// MidiEventList::last -- Alias for MidiEventList::back().
+//
+
+MidiEvent& MidiEventList::last(void) {
+	return back();
+}
+
+
+const MidiEvent& MidiEventList::last(void) const {
+	return back();
+}
+
+
+
+//////////////////////////////
+//
+// MidiEventList::getEvent -- The same thing as operator[], for
+//      internal use when operator[] would look more messy.
+//
+
+MidiEvent& MidiEventList::getEvent(int index) {
+	return *list[index];
+}
+
+
+const MidiEvent& MidiEventList::getEvent(int index) const {
+	return *list[index];
+}
+
+
+
+//////////////////////////////
+//
+// MidiEventList::clear -- De-allocate any MidiEvents present in the list
+//    and set the size of the list to 0.
+//
+
+void MidiEventList::clear(void) {
+	for (auto& item : list) {
+		if (item != NULL) {
+			delete item;
+			item = NULL;
+		}
+	}
+	list.resize(0);
+}
+
+
+
+//////////////////////////////
+//
+// MidiEventList::data -- Return the low-level array of MidiMessage
+//     pointers.  This is useful for applying your own sorting
+//     function to the list.
+//
+
+MidiEvent** MidiEventList::data(void) {
+	return list.data();
+}
+
+
+
+//////////////////////////////
+//
+// MidiEventList::reserve --  Pre-allocate space in the list for storing
+//     elements.
+//
+
+void MidiEventList::reserve(int rsize) {
+	if (rsize > (int)list.size()) {
+		list.reserve(rsize);
+	}
+}
+
+
+//////////////////////////////
+//
+// MidiEventList::getSize -- Return the number of MidiEvents stored
+//     in the list.
+//
+
+int MidiEventList::getSize(void) const {
+	return (int)list.size();
+}
+
+//
+// MidiEventList::size -- Alias for MidiEventList::getSize().
+//
+
+int MidiEventList::size(void) const {
+	return getSize();
+}
+
+//
+// MidiEventList::getEventCount -- Alias for MidiEventList::getSize().
+//
+
+int MidiEventList::getEventCount(void) const {
+	return getSize();
+}
+
+
+
+//////////////////////////////
+//
+// MidiEventList::append -- add a MidiEvent at the end of the list.  Returns
+//     the index of the appended event.
+//
+
+int MidiEventList::append(MidiEvent& event) {
+	MidiEvent* ptr = new MidiEvent(event);
+	list.push_back(ptr);
+	return (int)list.size()-1;
+}
+
+//
+// MidiEventList::push -- Alias for MidiEventList::append().
+//
+
+int MidiEventList::push(MidiEvent& event) {
+	return append(event);
+}
+
+//
+// MidiEventList::push_back -- Alias for MidiEventList::append().
+//
+
+int MidiEventList::push_back(MidiEvent& event) {
+	return append(event);
+}
+
+
+
+//////////////////////////////
+//
+// MidiEventList::removeEmpties -- Remove any MIDI message which contain no
+//    bytes.  This function first deallocates any empty MIDI events, and then
+//    removes them from the list of events.
+//
+
+void MidiEventList::removeEmpties(void) {
+	int count = 0;
+	for (auto& item : list) {
+		if (item->empty()) {
+			delete item;
+			item = NULL;
+			count++;
+		}
+	}
+	if (count == 0) {
+		return;
+	}
+	std::vector<MidiEvent*> newlist;
+	newlist.reserve(list.size() - count);
+	for (auto& item : list) {
+		if (item) {
+			newlist.push_back(item);
+		}
+	}
+	list.swap(newlist);
+}
+
+
+
+//////////////////////////////
+//
+// MidiEventList::linkNotePairs -- Match note-ones and note-offs together
+//   There are two models that can be done if two notes are overlapping
+//   on the same pitch: the first note-off affects the last note-on,
+//   or the first note-off affects the first note-on.  Currently  the
+//   first note-off affects the last note-on, but both methods could
+//   be implemented with user selectability.  The current state of the
+//   track is assumed to be in time-sorted order.  Returns the number
+//   of linked notes (note-on/note-off pairs).
+//
+
+int MidiEventList::linkEventPairs(void) {
+	return linkNotePairs();
+}
+
+
+int MidiEventList::linkNotePairs(void) {
+
+	// Note-on states:
+	// dimension 1: MIDI channel (0-15)
+	// dimension 2: MIDI key     (0-127)  (but 0 not used for note-ons)
+	// dimension 3: List of active note-ons or note-offs.
+	std::vector<std::vector<std::vector<MidiEvent*>>> noteons;
+	noteons.resize(16);
+	for (auto& noteon : noteons) {
+		noteon.resize(128);
+	}
+
+	// Controller linking: The following General MIDI controller numbers are
+	// also monitored for linking within the track (but not between tracks).
+	// hex dec  name                                    range
+	// 40  64   Hold pedal (Sustain) on/off             0..63=off  64..127=on
+	// 41  65   Portamento on/off                       0..63=off  64..127=on
+	// 42  66   Sustenuto Pedal on/off                  0..63=off  64..127=on
+	// 43  67   Soft Pedal on/off                       0..63=off  64..127=on
+	// 44  68   Legato Pedal on/off                     0..63=off  64..127=on
+	// 45  69   Hold Pedal 2 on/off                     0..63=off  64..127=on
+	// 50  80   General Purpose Button                  0..63=off  64..127=on
+	// 51  81   General Purpose Button                  0..63=off  64..127=on
+	// 52  82   General Purpose Button                  0..63=off  64..127=on
+	// 53  83   General Purpose Button                  0..63=off  64..127=on
+	// 54  84   Undefined on/off                        0..63=off  64..127=on
+	// 55  85   Undefined on/off                        0..63=off  64..127=on
+	// 56  86   Undefined on/off                        0..63=off  64..127=on
+	// 57  87   Undefined on/off                        0..63=off  64..127=on
+	// 58  88   Undefined on/off                        0..63=off  64..127=on
+	// 59  89   Undefined on/off                        0..63=off  64..127=on
+	// 5A  90   Undefined on/off                        0..63=off  64..127=on
+	// 7A 122   Local Keyboard On/Off                   0..63=off  64..127=on
+
+	// first keep track of whether the controller is an on/off switch:
+	std::vector<std::pair<int, int>> contmap;
+	contmap.resize(128);
+	std::pair<int, int> zero(0, 0);
+	std::fill(contmap.begin(), contmap.end(), zero);
+	contmap[64].first  = 1;   contmap[64].second = 0;
+	contmap[65].first  = 1;   contmap[65].second = 1;
+	contmap[66].first  = 1;   contmap[66].second = 2;
+	contmap[67].first  = 1;   contmap[67].second = 3;
+	contmap[68].first  = 1;   contmap[68].second = 4;
+	contmap[69].first  = 1;   contmap[69].second = 5;
+	contmap[80].first  = 1;   contmap[80].second = 6;
+	contmap[81].first  = 1;   contmap[81].second = 7;
+	contmap[82].first  = 1;   contmap[82].second = 8;
+	contmap[83].first  = 1;   contmap[83].second = 9;
+	contmap[84].first  = 1;   contmap[84].second = 10;
+	contmap[85].first  = 1;   contmap[85].second = 11;
+	contmap[86].first  = 1;   contmap[86].second = 12;
+	contmap[87].first  = 1;   contmap[87].second = 13;
+	contmap[88].first  = 1;   contmap[88].second = 14;
+	contmap[89].first  = 1;   contmap[89].second = 15;
+	contmap[90].first  = 1;   contmap[90].second = 16;
+	contmap[122].first = 1;   contmap[122].second = 17;
+
+	// dimensions:
+	// 1: mapped controller (0 to 17)
+	// 2: channel (0 to 15)
+	std::vector<std::vector<MidiEvent*>> contevents;
+	contevents.resize(18);
+	std::vector<std::vector<int>> oldstates;
+	oldstates.resize(18);
+	for (int i=0; i<18; i++) {
+		contevents[i].resize(16);
+		std::fill(contevents[i].begin(), contevents[i].end(), nullptr);
+		oldstates[i].resize(16);
+		std::fill(oldstates[i].begin(), oldstates[i].end(), -1);
+	}
+
+	// Now iterate through the MidiEventList keeping track of note and
+	// select controller states and linking notes/controllers as needed.
+	int channel;
+	int key;
+	int contnum;
+	int contval;
+	int conti;
+	int contstate;
+	int counter = 0;
+	MidiEvent* mev;
+	MidiEvent* noteon;
+	for (int i=0; i<getSize(); i++) {
+		mev = &getEvent(i);
+		mev->unlinkEvent();
+		if (mev->isNoteOn()) {
+			// store the note-on to pair later with a note-off message.
+			key = mev->getKeyNumber();
+			channel = mev->getChannel();
+			noteons[channel][key].push_back(mev);
+		} else if (mev->isNoteOff()) {
+			key = mev->getKeyNumber();
+			channel = mev->getChannel();
+			if (noteons[channel][key].size() > 0) {
+				noteon = noteons[channel][key].back();
+				noteons[channel][key].pop_back();
+				noteon->linkEvent(mev);
+				counter++;
+			}
+		} else if (mev->isController()) {
+			contnum = mev->getP1();
+			if (contmap[contnum].first) {
+				conti     = contmap[contnum].second;
+				channel   = mev->getChannel();
+				contval   = mev->getP2();
+				contstate = contval < 64 ? 0 : 1;
+				if ((oldstates[conti][channel] == -1) && contstate) {
+					// a newly initialized onstate was detected, so store for
+					// later linking to an off state.
+					contevents[conti][channel] = mev;
+					oldstates[conti][channel] = contstate;
+				} else if (oldstates[conti][channel] == contstate) {
+					// the controller state is redundant and will be ignored.
+				} else if ((oldstates[conti][channel] == 0) && contstate) {
+					// controller is currently off, so store on-state for next link
+					contevents[conti][channel] = mev;
+					oldstates[conti][channel] = contstate;
+				} else if ((oldstates[conti][channel] == 1) && (contstate == 0)) {
+					// controller has just been turned off, so link to
+					// stored on-message.
+					contevents[conti][channel]->linkEvent(mev);
+					oldstates[conti][channel] = contstate;
+					// not necessary, but maybe use for something later:
+					contevents[conti][channel] = mev;
+				}
+			}
+		}
+	}
+	return counter;
+}
+
+
+
+//////////////////////////////
+//
+// MidiEventList::clearLinks -- remove all note-on/note-off links.
+//
+
+void MidiEventList::clearLinks(void) {
+	for (int i=0; i<(int)getSize(); i++) {
+		getEvent(i).unlinkEvent();
+	}
+}
+
+
+
+//////////////////////////////
+//
+// MidiEventList::clearSequence -- Remove any sequence serial numbers from
+//   MidiEvents in the list.  This will cause the default ordering by
+//   sortTracks() to be used, in which case the ordering of MidiEvents
+//   occurring at the same tick may switch their ordering.
+//
+
+void MidiEventList::clearSequence(void) {
+	for (int i=0; i<getEventCount(); i++) {
+		getEvent(i).seq = 0;
+	}
+}
+
+
+
+//////////////////////////////
+//
+// MidiEventList::markSequence -- Assign a sequence serial number to
+//   every MidiEvent in the event list.  This is useful if you want
+//   to preseve the order of MIDI messages in a track when they occur
+//   at the same tick time.  Particularly for use with joinTracks()
+//   or sortTracks().  markSequence will be done automatically when
+//   a MIDI file is read, in case the ordering of events occurring at
+//   the same time is important.  Use clearSequence() to use the
+//   default sorting behavior of sortTracks() when events occur at the
+//   same time.  Returns the next serial number that has not yet been
+//   used.
+//   default value: sequence = 1.
+//
+
+int MidiEventList::markSequence(int sequence) {
+	for (int i=0; i<getEventCount(); i++) {
+		getEvent(i).seq = sequence++;
+	}
+	return sequence;
+}
+
+
+///////////////////////////////////////////////////////////////////////////
+//
+// protected functions --
+//
+
+
+//////////////////////////////
+//
+// MidiEventList::detach -- De-allocate any MidiEvents present in the list
+//    and set the size of the list to 0.
+//
+
+
+void MidiEventList::detach(void) {
+	list.resize(0);
+}
+
+
+
+//////////////////////////////
+//
+// MidiEventList::push_back_no_copy -- add a MidiEvent at the end of
+//     the list.  The event is not copied, but memory from the
+//     remote location is used.  Returns the index of the appended event.
+//
+
+int MidiEventList::push_back_no_copy(MidiEvent* event) {
+	list.push_back(event);
+	return (int)list.size()-1;
+}
+
+
+
+//////////////////////////////
+//
+// MidiEventList::operator=(MidiEventList) -- Assignment.
+//
+
+MidiEventList& MidiEventList::operator=(MidiEventList& other) {
+	list.swap(other.list);
+	return *this;
+}
+
+
+///////////////////////////////////////////////////////////////////////////
+//
+// private functions
+//
+
+//////////////////////////////
+//
+// MidiEventList::sort -- Private because the MidiFile class keeps
+//    track of delta versus absolute tick states of the MidiEventList,
+//    and sorting is only allowed in absolute tick state (The MidiEventList
+//    does not know about delta/absolute tick states of its contents).
+//
+
+void MidiEventList::sort(void) {
+	qsort(data(), getEventCount(), sizeof(MidiEvent*), eventcompare);
+}
+
+
+
+///////////////////////////////////////////////////////////////////////////
+//
+// external functions
+//
+
+//////////////////////////////
+//
+// eventcompare -- Event comparison function for sorting tracks.
+//
+// Sorting rules:
+//    (1) sort by (absolute) tick value; otherwise, if tick values are the same:
+//    (2) end-of-track meta message is always last.
+//    (3) other meta-messages come before regular MIDI messages.
+//    (4) note-offs come after all other regular MIDI messages except note-ons.
+//    (5) note-ons come after all other regular MIDI messages.
+//
+
+int eventcompare(const void* a, const void* b) {
+	MidiEvent& aevent = **((MidiEvent**)a);
+	MidiEvent& bevent = **((MidiEvent**)b);
+
+	if (aevent.tick > bevent.tick) {
+		// aevent occurs after bevent
+		return +1;
+	} else if (aevent.tick < bevent.tick) {
+		// aevent occurs before bevent
+		return -1;
+	} else if ((aevent.seq != 0) && (bevent.seq != 0) && (aevent.seq > bevent.seq)) {
+		// aevent sequencing state occurs after bevent
+		// see MidiEventList::markSequence()
+		return +1;
+	} else if ((aevent.seq != 0) && (bevent.seq != 0) && (aevent.seq < bevent.seq)) {
+		// aevent sequencing state occurs before bevent
+		// see MidiEventList::markSequence()
+		return -1;
+	} else if (aevent.getP0() == 0xff && aevent.getP1() == 0x2f) {
+		// end-of-track meta-message should always be last (but won't really
+		// matter since the writing function ignores all end-of-track messages
+		// and writes its own.
+		return +1;
+	} else if (bevent.getP0() == 0xff && bevent.getP1() == 0x2f) {
+		// end-of-track meta-message should always be last (but won't really
+		// matter since the writing function ignores all end-of-track messages
+		// and writes its own.
+		return -1;
+	} else if (aevent.getP0() == 0xff && bevent.getP0() != 0xff) {
+		// other meta-messages are placed before real MIDI messages
+		return -1;
+	} else if (aevent.getP0() != 0xff && bevent.getP0() == 0xff) {
+		// other meta-messages are placed before real MIDI messages
+		return +1;
+	} else if (((aevent.getP0() & 0xf0) == 0x90) && (aevent.getP2() != 0)) {
+		// note-ons come after all other types of MIDI messages
+		return +1;
+	} else if (((bevent.getP0() & 0xf0) == 0x90) && (bevent.getP2() != 0)) {
+		// note-ons come after all other types of MIDI messages
+		return -1;
+	} else if (((aevent.getP0() & 0xf0) == 0x90) || ((aevent.getP0() & 0xf0) == 0x80)) {
+		// note-offs come after all other MIDI messages (except note-ons)
+		return +1;
+	} else if (((bevent.getP0() & 0xf0) == 0x90) || ((bevent.getP0() & 0xf0) == 0x80)) {
+		// note-offs come after all other MIDI messages (except note-ons)
+		return -1;
+	} else if (((aevent.getP0() & 0xf0) == 0xb0) && ((bevent.getP0() & 0xf0) == 0xb0)) {
+		// both events are continuous controllers.  Sort them by controller number
+		if (aevent.getP1() > bevent.getP1()) {
+			return +1;
+		} if (aevent.getP1() < bevent.getP1()) {
+			return -1;
+		} else {
+			// same controller number, so sort by data value
+			if (aevent.getP2() > bevent.getP2()) {
+				return +1;
+			} if (aevent.getP2() < bevent.getP2()) {
+				return -1;
+			} else {
+				return 0;
+			}
+		}
+	} else {
+		return 0;
+	}
+}
+
+
+} // end namespace smf
+
+
+

src/3rdparty/midifile/MidiEventList.h

@@ -0,0 +1,82 @@
+//
+// Programmer:    Craig Stuart Sapp <craig@ccrma.stanford.edu>
+// Creation Date: Sat Feb 14 21:55:38 PST 2015
+// Last Modified: Sat Apr 21 10:52:19 PDT 2018 Removed using namespace std;
+// Filename:      midifile/include/MidiEventList.h
+// Website:       http://midifile.sapp.org
+// Syntax:        C++11
+// vim:           ts=3 noexpandtab
+//
+// Description:   A class that stores a MidiEvents for a MidiFile track.
+//
+
+#ifndef _MIDIEVENTLIST_H_INCLUDED
+#define _MIDIEVENTLIST_H_INCLUDED
+
+#include "MidiEvent.h"
+
+#include <vector>
+
+
+namespace smf {
+
+class MidiEventList {
+	public:
+		                 MidiEventList      (void);
+		                 MidiEventList      (const MidiEventList& other);
+		                 MidiEventList      (MidiEventList&& other);
+
+		                ~MidiEventList      ();
+
+		MidiEventList&   operator=          (MidiEventList& other);
+		MidiEvent&       operator[]         (int index);
+		const MidiEvent& operator[]         (int index) const;
+
+		MidiEvent&       back               (void);
+		const MidiEvent& back               (void) const;
+		MidiEvent&       last               (void);
+		const MidiEvent& last               (void) const;
+		MidiEvent&       getEvent           (int index);
+		const MidiEvent& getEvent           (int index) const;
+		void             clear              (void);
+		void             reserve            (int rsize);
+		int              getEventCount      (void) const;
+		int              getSize            (void) const;
+		int              size               (void) const;
+		void             removeEmpties      (void);
+		int              linkNotePairs      (void);
+		int              linkEventPairs     (void);
+		void             clearLinks         (void);
+		void             clearSequence      (void);
+		int              markSequence       (int sequence = 1);
+
+		int              push               (MidiEvent& event);
+		int              push_back          (MidiEvent& event);
+		int              append             (MidiEvent& event);
+
+		// careful when using these, intended for internal use in MidiFile class:
+		void             detach             (void);
+		int              push_back_no_copy  (MidiEvent* event);
+
+		// access to the list of MidiEvents for sorting with an external function:
+		MidiEvent**      data               (void);
+
+	protected:
+		std::vector<MidiEvent*> list;
+
+	private:
+		void             sort                (void);
+
+	// MidiFile class calls sort()
+	friend class MidiFile;
+};
+
+
+int eventcompare(const void* a, const void* b);
+
+} // end of namespace smf
+
+#endif /* _MIDIEVENTLIST_H_INCLUDED */
+
+
+

src/3rdparty/midifile/MidiFile.h

@@ -0,0 +1,332 @@
+//
+// Programmer:    Craig Stuart Sapp <craig@ccrma.stanford.edu>
+// Creation Date: Fri Nov 26 14:12:01 PST 1999
+// Last Modified: Mon Jan 18 20:54:04 PST 2021 Added readSmf().
+// Filename:      midifile/include/MidiFile.h
+// Website:       http://midifile.sapp.org
+// Syntax:        C++11
+// vim:           ts=3 noexpandtab
+//
+// Description:   A class that can read/write Standard MIDI files.
+//                MIDI data is stored by track in an array.
+//
+
+#ifndef _MIDIFILE_H_INCLUDED
+#define _MIDIFILE_H_INCLUDED
+
+#include "MidiEventList.h"
+
+#include <fstream>
+#include <istream>
+#include <string>
+#include <vector>
+
+
+namespace smf {
+
+enum {
+    TRACK_STATE_SPLIT  = 0, // Tracks are separated into separate vector postions.
+    TRACK_STATE_JOINED = 1  // Tracks are merged into a single vector position,
+};                          // like a Type-0 MIDI file, but reversible.
+
+enum {
+    TIME_STATE_DELTA    = 0, // MidiMessage::ticks are in delta time format (like MIDI file).
+    TIME_STATE_ABSOLUTE = 1  // MidiMessage::ticks are in absolute time format (0=start time).
+};
+
+class _TickTime {
+	public:
+		int    tick;
+		double seconds;
+};
+
+
+class MidiFile {
+	public:
+		               MidiFile                    (void);
+		               MidiFile                    (const std::string& filename);
+		               MidiFile                    (std::istream& input);
+		               MidiFile                    (const MidiFile& other);
+		               MidiFile                    (MidiFile&& other);
+
+		              ~MidiFile                    ();
+
+		MidiFile&      operator=                   (const MidiFile& other);
+		MidiFile&      operator=                   (MidiFile&& other);
+
+		// Reading/writing functions:
+
+		// Auto-detected SMF or ASCII-encoded SMF (decoded with Binasc class):
+		bool           read                        (const std::string& filename);
+		bool           read                        (std::istream& instream);
+		bool           readBase64                  (const std::string& base64data);
+		bool           readBase64                  (std::istream& instream);
+
+		// Only allow Standard MIDI File input:
+		bool           readSmf                     (const std::string& filename);
+		bool           readSmf                     (std::istream& instream);
+
+		bool           write                       (const std::string& filename);
+		bool           write                       (std::ostream& out);
+		bool           writeBase64                 (const std::string& out, int width = 0);
+		bool           writeBase64                 (std::ostream& out, int width = 0);
+		std::string    getBase64                   (int width = 0);
+		bool           writeHex                    (const std::string& filename, int width = 25);
+		bool           writeHex                    (std::ostream& out, int width = 25);
+		bool           writeBinasc                 (const std::string& filename);
+		bool           writeBinasc                 (std::ostream& out);
+		bool           writeBinascWithComments     (const std::string& filename);
+		bool           writeBinascWithComments     (std::ostream& out);
+		bool           status                      (void) const;
+
+		// track-related functions:
+		const MidiEventList& operator[]            (int aTrack) const;
+		MidiEventList&   operator[]                (int aTrack);
+		int              getTrackCount             (void) const;
+		int              getNumTracks              (void) const;
+		int              size                      (void) const;
+		void             removeEmpties             (void);
+
+		// tick-related functions:
+		void             makeDeltaTicks            (void);
+		void             deltaTicks                (void);
+		void             makeAbsoluteTicks         (void);
+		void             absoluteTicks             (void);
+		int              getTickState              (void) const;
+		bool             isDeltaTicks              (void) const;
+		bool             isAbsoluteTicks           (void) const;
+
+		// join/split track functionality:
+		void             joinTracks                (void);
+		void             splitTracks               (void);
+		void             splitTracksByChannel      (void);
+		int              getTrackState             (void) const;
+		int              hasJoinedTracks           (void) const;
+		int              hasSplitTracks            (void) const;
+		int              getSplitTrack             (int track, int index) const;
+		int              getSplitTrack             (int index) const;
+
+		// track sorting funcionality:
+		void             sortTrack                 (int track);
+		void             sortTracks                (void);
+		void             markSequence              (void);
+		void             markSequence              (int track, int sequence = 1);
+		void             clearSequence             (void);
+		void             clearSequence             (int track);
+
+		// track manipulation functionality:
+		int              addTrack                  (void);
+		int              addTrack                  (int count);
+		int              addTracks                 (int count);
+		void             deleteTrack               (int aTrack);
+		void             mergeTracks               (int aTrack1, int aTrack2);
+		int              getTrackCountAsType1      (void);
+
+		// ticks-per-quarter related functions:
+		void             setMillisecondTicks       (void);
+		int              getTicksPerQuarterNote    (void) const;
+		int              getTPQ                    (void) const;
+		void             setTicksPerQuarterNote    (int ticks);
+		void             setTPQ                    (int ticks);
+
+		// physical-time analysis functions:
+		void             doTimeAnalysis            (void);
+		double           getTimeInSeconds          (int aTrack, int anIndex);
+		double           getTimeInSeconds          (int tickvalue);
+		double           getAbsoluteTickTime       (double starttime);
+		int              getFileDurationInTicks    (void);
+		double           getFileDurationInQuarters (void);
+		double           getFileDurationInSeconds  (void);
+
+		// note-analysis functions:
+		int              linkNotePairs             (void);
+		int              linkEventPairs            (void);
+		void             clearLinks                (void);
+
+		// filename functions:
+		void             setFilename               (const std::string& aname);
+		const char*      getFilename               (void) const;
+
+		// event functionality:
+		MidiEvent*       addEvent                  (int aTrack, int aTick,
+		                                            std::vector<uchar>& midiData);
+		MidiEvent*       addEvent                  (MidiEvent& mfevent);
+		MidiEvent*       addEvent                  (int aTrack, MidiEvent& mfevent);
+		MidiEvent&       getEvent                  (int aTrack, int anIndex);
+		const MidiEvent& getEvent                  (int aTrack, int anIndex) const;
+		int              getEventCount             (int aTrack) const;
+		int              getNumEvents              (int aTrack) const;
+		void             allocateEvents            (int track, int aSize);
+		void             erase                     (void);
+		void             clear                     (void);
+		void             clear_no_deallocate       (void);
+
+		// MIDI message adding convenience functions:
+		MidiEvent*        addNoteOn               (int aTrack, int aTick,
+		                                           int aChannel, int key,
+		                                           int vel);
+		MidiEvent*        addNoteOff              (int aTrack, int aTick,
+		                                           int aChannel, int key,
+		                                           int vel);
+		MidiEvent*        addNoteOff              (int aTrack, int aTick,
+		                                           int aChannel, int key);
+		MidiEvent*        addController           (int aTrack, int aTick,
+		                                           int aChannel, int num,
+		                                           int value);
+		MidiEvent*        addPatchChange          (int aTrack, int aTick,
+		                                           int aChannel, int patchnum);
+		MidiEvent*        addTimbre               (int aTrack, int aTick,
+		                                           int aChannel, int patchnum);
+		MidiEvent*        addPitchBend            (int aTrack, int aTick,
+		                                           int aChannel, double amount);
+
+		// RPN settings:
+		void              setPitchBendRange       (int aTrack, int aTick,
+		                                           int aChannel, double range);
+
+		// Controller message adding convenience functions:
+		MidiEvent*        addSustain              (int aTrack, int aTick,
+		                                           int aChannel, int value);
+		MidiEvent*        addSustainPedal         (int aTrack, int aTick,
+		                                           int aChannel, int value);
+		MidiEvent*        addSustainOn            (int aTrack, int aTick,
+		                                           int aChannel);
+		MidiEvent*        addSustainPedalOn       (int aTrack, int aTick,
+		                                           int aChannel);
+		MidiEvent*        addSustainOff           (int aTrack, int aTick,
+		                                           int aChannel);
+		MidiEvent*        addSustainPedalOff      (int aTrack, int aTick,
+		                                           int aChannel);
+
+		// Meta-event adding convenience functions:
+		MidiEvent*         addMetaEvent           (int aTrack, int aTick,
+		                                           int aType,
+		                                           std::vector<uchar>& metaData);
+		MidiEvent*         addMetaEvent           (int aTrack, int aTick,
+		                                           int aType,
+		                                           const std::string& metaData);
+		MidiEvent*         addText                (int aTrack, int aTick,
+		                                           const std::string& text);
+		MidiEvent*         addCopyright           (int aTrack, int aTick,
+		                                           const std::string& text);
+		MidiEvent*         addTrackName           (int aTrack, int aTick,
+		                                           const std::string& name);
+		MidiEvent*         addInstrumentName      (int aTrack, int aTick,
+		                                           const std::string& name);
+		MidiEvent*         addLyric               (int aTrack, int aTick,
+		                                           const std::string& text);
+		MidiEvent*         addMarker              (int aTrack, int aTick,
+		                                           const std::string& text);
+		MidiEvent*         addCue                 (int aTrack, int aTick,
+		                                           const std::string& text);
+		MidiEvent*         addTempo               (int aTrack, int aTick,
+		                                           double aTempo);
+		MidiEvent*         addKeySignature        (int aTrack, int aTick,
+		                                           int fifths, bool mode = 0);
+		MidiEvent*         addTimeSignature       (int aTrack, int aTick,
+		                                           int top, int bottom,
+		                                           int clocksPerClick = 24,
+		                                           int num32dsPerQuarter = 8);
+		MidiEvent*         addCompoundTimeSignature(int aTrack, int aTick,
+		                                           int top, int bottom,
+		                                           int clocksPerClick = 36,
+		                                           int num32dsPerQuarter = 8);
+
+		uchar              readByte               (std::istream& input);
+
+		// static functions:
+		static ushort        readLittleEndian2Bytes  (std::istream& input);
+		static ulong         readLittleEndian4Bytes  (std::istream& input);
+		static std::ostream& writeLittleEndianUShort (std::ostream& out,
+		                                              ushort value);
+		static std::ostream& writeBigEndianUShort    (std::ostream& out,
+		                                              ushort value);
+		static std::ostream& writeLittleEndianShort  (std::ostream& out,
+		                                              short value);
+		static std::ostream& writeBigEndianShort     (std::ostream& out,
+		                                              short value);
+		static std::ostream& writeLittleEndianULong  (std::ostream& out,
+		                                              ulong value);
+		static std::ostream& writeBigEndianULong     (std::ostream& out,
+		                                              ulong value);
+		static std::ostream& writeLittleEndianLong   (std::ostream& out,
+		                                              long value);
+		static std::ostream& writeBigEndianLong      (std::ostream& out,
+		                                              long value);
+		static std::ostream& writeLittleEndianFloat  (std::ostream& out,
+		                                              float value);
+		static std::ostream& writeBigEndianFloat     (std::ostream& out,
+		                                              float value);
+		static std::ostream& writeLittleEndianDouble (std::ostream& out,
+		                                              double value);
+		static std::ostream& writeBigEndianDouble    (std::ostream& out,
+		                                              double value);
+		static std::string   getGMInstrumentName     (int patchIndex);
+
+	protected:
+		// m_events == Lists of MidiEvents for each MIDI file track.
+		std::vector<MidiEventList*> m_events;
+
+		// m_ticksPerQuarterNote == A value for the MIDI file header
+		// which represents the number of ticks in a quarter note
+		// that are used as units for the delta times for MIDI events
+		// in MIDI file track data.
+		int m_ticksPerQuarterNote = 120;
+
+		// m_theTrackState == state variable for whether the tracks
+		// are joined or split.
+		int m_theTrackState = TRACK_STATE_SPLIT;
+
+		// m_theTimeState == state variable for whether the MidiEvent::tick
+		// variable contain absolute ticks since the start of the file's
+		// time, or delta ticks since the last MIDI event in the track.
+		int m_theTimeState = TIME_STATE_ABSOLUTE;
+
+		// m_readFileName == the filename of the last file read into
+		// the object.
+		std::string m_readFileName;
+
+		// m_timemapvalid ==
+		bool m_timemapvalid = false;
+
+		// m_timemap ==
+		std::vector<_TickTime> m_timemap;
+
+		// m_rwstatus == True if last read was successful, false if a problem.
+		bool m_rwstatus = true;
+
+		// m_linkedEventQ == True if link analysis has been done.
+		bool m_linkedEventsQ = false;
+
+	private:
+		int         extractMidiData                 (std::istream& inputfile,
+		                                             std::vector<uchar>& array,
+		                                             uchar& runningCommand);
+		ulong       readVLValue                     (std::istream& inputfile);
+		ulong       unpackVLV                       (uchar a = 0, uchar b = 0,
+		                                             uchar c = 0, uchar d = 0,
+		                                             uchar e = 0);
+		void        writeVLValue                    (long aValue,
+		                                             std::vector<uchar>& data);
+		int         makeVLV                         (uchar *buffer, int number);
+		static int  ticksearch                      (const void* A, const void* B);
+		static int  secondsearch                    (const void* A, const void* B);
+		void        buildTimeMap                    (void);
+		double      linearTickInterpolationAtSecond (double seconds);
+		double      linearSecondInterpolationAtTick (int ticktime);
+		std::string base64Encode                    (const std::string &input);
+		std::string base64Decode                    (const std::string &input);
+
+		static const std::string encodeLookup;
+		static const std::vector<int> decodeLookup;
+		static const char *GMinstrument[128];
+};
+
+} // end of namespace smf
+
+std::ostream& operator<<(std::ostream& out, smf::MidiFile& aMidiFile);
+
+#endif /* _MIDIFILE_H_INCLUDED */
+
+
+

src/3rdparty/midifile/MidiMessage.h

@@ -0,0 +1,219 @@
+//
+// Programmer:    Craig Stuart Sapp <craig@ccrma.stanford.edu>
+// Creation Date: Sat Feb 14 20:36:32 PST 2015
+// Last Modified: Sat Apr 21 10:52:19 PDT 2018 Removed using namespace std;
+// Filename:      midifile/include/MidiMessage.h
+// Website:       http://midifile.sapp.org
+// Syntax:        C++11
+// vim:           ts=3 noexpandtab
+//
+// Description:   Storage for bytes of a MIDI message for use in MidiFile
+//                class.
+//
+
+#ifndef _MIDIMESSAGE_H_INCLUDED
+#define _MIDIMESSAGE_H_INCLUDED
+
+#include <iostream>
+#include <string>
+#include <utility>
+#include <vector>
+
+
+namespace smf {
+
+typedef unsigned char  uchar;
+typedef unsigned short ushort;
+typedef unsigned long  ulong;
+
+class MidiMessage : public std::vector<uchar> {
+
+	public:
+		               MidiMessage          (void);
+		               MidiMessage          (int command);
+		               MidiMessage          (int command, int p1);
+		               MidiMessage          (int command, int p1, int p2);
+		               MidiMessage          (const MidiMessage& message);
+		               MidiMessage          (const std::vector<uchar>& message);
+		               MidiMessage          (const std::vector<char>& message);
+		               MidiMessage          (const std::vector<int>& message);
+
+		              ~MidiMessage          ();
+
+		MidiMessage&   operator=            (const MidiMessage& message);
+		MidiMessage&   operator=            (const std::vector<uchar>& bytes);
+		MidiMessage&   operator=            (const std::vector<char>& bytes);
+		MidiMessage&   operator=            (const std::vector<int>& bytes);
+
+		void           sortTrack            (void);
+		void           sortTrackWithSequence(void);
+
+		static std::vector<uchar> intToVlv  (int value);
+		static double  frequencyToSemitones (double frequency, double a4frequency = 440.0);
+
+		// data access convenience functions (returns -1 if not present):
+		int            getP0                (void) const;
+		int            getP1                (void) const;
+		int            getP2                (void) const;
+		int            getP3                (void) const;
+		void           setP0                (int value);
+		void           setP1                (int value);
+		void           setP2                (int value);
+		void           setP3                (int value);
+
+		int            getSize              (void) const;
+		void           setSize              (int asize);
+		int            setSizeToCommand     (void);
+		int            resizeToCommand      (void);
+
+		// note-message convenience functions:
+		int            getKeyNumber         (void) const;
+		int            getVelocity          (void) const;
+		void           setKeyNumber         (int value);
+		void           setVelocity          (int value);
+		void           setSpelling          (int base7, int accidental);
+		void           getSpelling          (int& base7, int& accidental);
+
+		// controller-message convenience functions:
+		int            getControllerNumber  (void) const;
+		int            getControllerValue   (void) const;
+
+		int            getCommandNibble     (void) const;
+		int            getCommandByte       (void) const;
+		int            getChannelNibble     (void) const;
+		int            getChannel           (void) const;
+
+		void           setCommandByte       (int value);
+		void           setCommand           (int value);
+		void           setCommand           (int value, int p1);
+		void           setCommand           (int value, int p1, int p2);
+		void           setCommandNibble     (int value);
+		void           setChannelNibble     (int value);
+		void           setChannel           (int value);
+		void           setParameters        (int p1, int p2);
+		void           setParameters        (int p1);
+		void           setMessage           (const std::vector<uchar>& message);
+		void           setMessage           (const std::vector<char>& message);
+		void           setMessage           (const std::vector<int>& message);
+
+		// message-type convenience functions:
+		bool           isMetaMessage        (void) const;
+		bool             isMeta             (void) const;
+		bool           isNote               (void) const;
+		bool             isNoteOff          (void) const;
+		bool             isNoteOn           (void) const;
+		bool           isAftertouch         (void) const;
+		bool           isController         (void) const;
+		bool             isSustain          (void) const;  // controller 64
+		bool             isSustainOn        (void) const;
+		bool             isSustainOff       (void) const;
+		bool             isSoft             (void) const;  // controller 67
+		bool             isSoftOn           (void) const;
+		bool             isSoftOff          (void) const;
+		bool           isPatchChange        (void) const;
+		bool             isTimbre           (void) const;
+		bool           isPressure           (void) const;
+		bool           isPitchbend          (void) const;
+		bool           isEmpty              (void) const;  // see MidiFile::removeEmpties()
+
+		// helper functions to create various MidiMessages:
+		void           makeNoteOn           (int channel, int key, int velocity);
+		void           makeNoteOff          (int channel, int key, int velocity);
+		void           makeNoteOff          (int channel, int key);
+		void           makeNoteOff          (void);
+		void           makePatchChange      (int channel, int patchnum);
+		void           makeTimbre           (int channel, int patchnum);
+		void           makeController       (int channel, int num, int value);
+		void           makePitchBend        (int channel, int lsb, int msb);
+		void           makePitchBend        (int channel, int value);
+		void           makePitchBendDouble  (int channel, double value);
+		void           makePitchbend        (int channel, int lsb, int msb) { makePitchBend(channel, lsb, msb); }
+		void           makePitchbend        (int channel, int value) { makePitchBend(channel, value); }
+		void           makePitchbendDouble  (int channel, double value) { makePitchBendDouble(channel, value); }
+
+		// helper functions to create various continuous controller messages:
+		void           makeSustain          (int channel, int value);
+		void           makeSustainPedal     (int channel, int value);
+		void           makeSustainOn        (int channel);
+		void           makeSustainPedalOn   (int channel);
+		void           makeSustainOff       (int channel);
+		void           makeSustainPedalOff  (int channel);
+
+		// meta-message creation and helper functions:
+		void           makeMetaMessage      (int mnum, const std::string& data);
+		void           makeText             (const std::string& name);
+		void           makeCopyright        (const std::string& text);
+		void           makeTrackName        (const std::string& name);
+		void           makeInstrumentName   (const std::string& name);
+		void           makeLyric            (const std::string& text);
+		void           makeMarker           (const std::string& text);
+		void           makeCue              (const std::string& text);
+		void           makeKeySignature     (int fifths, bool mode = 0);
+		void           makeTimeSignature    (int top, int bottom,
+		                                     int clocksPerClick = 24,
+		                                     int num32dsPerQuarter = 8);
+
+		void           makeTempo            (double tempo) { setTempo(tempo); }
+		int            getTempoMicro        (void) const;
+		int            getTempoMicroseconds (void) const;
+		double         getTempoSeconds      (void) const;
+		double         getTempoBPM          (void) const;
+		double         getTempoTPS          (int tpq) const;
+		double         getTempoSPT          (int tpq) const;
+
+		int            getMetaType          (void) const;
+		bool           isText               (void) const;
+		bool           isCopyright          (void) const;
+		bool           isTrackName          (void) const;
+		bool           isInstrumentName     (void) const;
+		bool           isLyricText          (void) const;
+		bool           isMarkerText         (void) const;
+		bool           isTempo              (void) const;
+		bool           isTimeSignature      (void) const;
+		bool           isKeySignature       (void) const;
+		bool           isEndOfTrack         (void) const;
+
+		std::string    getMetaContent       (void) const;
+		void           setMetaContent       (const std::string& content);
+		void           setTempo             (double tempo);
+		void           setTempoMicroseconds (int microseconds);
+		void           setMetaTempo         (double tempo);
+
+
+		void           makeSysExMessage     (const std::vector<uchar>& data);
+
+		// helper functions to create MTS tunings by key (real-time sysex)
+
+		// MTS type 2: Real-time frequency assignment to a arbitrary list of MIDI key numbers.
+		// See page 2 of: https://docs.google.com/viewer?url=https://www.midi.org/component/edocman/midi-tuning-updated/fdocument?Itemid=9999
+		void           makeMts2_KeyTuningByFrequency  (int key, double frequency, int program = 0);
+		void           makeMts2_KeyTuningsByFrequency (int key, double frequency, int program = 0);
+		void           makeMts2_KeyTuningsByFrequency (std::vector<std::pair<int, double>>& mapping, int program = 0);
+		void           makeMts2_KeyTuningBySemitone   (int key, double semitone, int program = 0);
+		void           makeMts2_KeyTuningsBySemitone  (int key, double semitone, int program = 0);
+		void           makeMts2_KeyTuningsBySemitone  (std::vector<std::pair<int, double>>& mapping, int program = 0);
+
+		// MTS type 9: Real-time octave temperaments by +/- 100 cents deviation from ET
+		// See page 7 of: https://docs.google.com/viewer?url=https://www.midi.org/component/edocman/midi-tuning-updated/fdocument?Itemid=9999
+		void           makeMts9_TemperamentByCentsDeviationFromET (std::vector<double>& mapping, int referencePitchClass = 0, int channelMask = 0b1111111111111111);
+		void           makeTemperamentEqual(int referencePitchClass = 0, int channelMask = 0b1111111111111111);
+		void           makeTemperamentBad(double maxDeviationCents = 100.0, int referencePitchClass = 0, int channelMask = 0b1111111111111111);
+		void           makeTemperamentPythagorean(int referencePitchClass = 2, int channelMask = 0b1111111111111111);
+		void           makeTemperamentMeantone(double fraction = 0.25, int referencePitchClass = 2, int channelMask = 0b1111111111111111);
+		void           makeTemperamentMeantoneCommaQuarter(int referencePitchClass = 2, int channelMask = 0b1111111111111111);
+		void           makeTemperamentMeantoneCommaThird(int referencePitchClass = 2, int channelMask = 0b1111111111111111);
+		void           makeTemperamentMeantoneCommaHalf(int referencePitchClass = 2, int channelMask = 0b1111111111111111);
+
+};
+
+
+std::ostream& operator<<(std::ostream& out, MidiMessage& event);
+
+
+} // end of namespace smf
+
+
+#endif /* _MIDIMESSAGE_H_INCLUDED */
+
+
+

src/music/CMakeLists.txt

@@ -37,6 +37,12 @@ if(NOT OPTION_DEDICATED)
         CONDITION HAIKU
     )
 
+    add_files(
+        alsamidi.cpp
+        alsamidi.h
+        CONDITION ALSA_FOUND
+    )
+
     add_files(
         midi.h
         midifile.cpp

src/music/alsamidi.cpp

@@ -0,0 +1,604 @@
+/*
+ * This file is part of OpenTTD.
+ * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
+ * OpenTTD 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 General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** @file alsamidi.cpp Support for ALSA Linux MIDI. */
+
+#include "../stdafx.h"
+#include "../openttd.h"
+#include "alsamidi.h"
+#include "../base_media_base.h"
+#include "midifile.hpp"
+#include "../debug.h"
+#include "midi.h"
+#include <chrono>
+#include <thread>
+
+#include "../safeguards.h"
+
+/** Factory for ALSA MIDI player. */
+static FMusicDriver_AlsaMidi iFMusicDriver_AlsaMidi;
+
+std::optional<std::string_view> MusicDriver_AlsaMidi::Start(const StringList &parm)
+{
+	this->playing.store(false);
+	Debug(driver, 2, "ALSA MIDI: Start");
+	this->dev_port = (uint)GetDriverParamInt(parm, "port", UINT_MAX);
+	Debug(driver, 2, "ALSA MIDI: using MIDI device at port {}", dev_port);
+
+	// Open sequencer
+	if (snd_seq_open(&this->seq, "default", SND_SEQ_OPEN_OUTPUT, 0) < 0) {
+		return "Failed to open ALSA sequencer";
+	}
+
+	snd_seq_set_client_name(this->seq, "OpenTTD MIDI Out");
+
+	// Create port
+	this->seq_port = snd_seq_create_simple_port(this->seq, "MIDI Out",
+		SND_SEQ_PORT_CAP_READ|SND_SEQ_PORT_CAP_SUBS_READ,
+		SND_SEQ_PORT_TYPE_MIDI_GENERIC|SND_SEQ_PORT_TYPE_APPLICATION);
+
+	if (this->seq_port < 0) {
+		return "Failed to create ALSA sequencer port";
+	}
+
+	// Create event queue
+	Debug(driver, 2, "ALSA MIDI: Creating sequencer event queue");
+	this->queue_id = snd_seq_alloc_named_queue(seq, "OpenTTD Sequencer Queue");
+	if (this->queue_id < 0) {
+		return "Failed to create ALSA sequencer event queue";
+	}
+
+	// Set a slightly larger event output buffer than normal
+	snd_seq_set_client_pool_output(this->seq, 1000);
+	snd_seq_set_client_pool_output_room(this->seq, 1000);
+	snd_seq_set_output_buffer_size(this->seq, 1000);
+
+	// Turn on nonblocking mode
+	snd_seq_nonblock(this->seq, 1);
+
+	snd_seq_addr_t sender, dest;
+
+	// Setup event port
+	sender.client = snd_seq_client_id(this->seq);
+	sender.port = this->seq_port;
+
+	dest.client = this->dev_port;
+	dest.port = this->seq_port;
+
+	snd_seq_port_subscribe_t* subs;
+	snd_seq_port_subscribe_alloca(&subs);
+	snd_seq_port_subscribe_set_sender(subs, &sender);
+	snd_seq_port_subscribe_set_dest(subs, &dest);
+
+	if (snd_seq_subscribe_port(this->seq, subs) < 0) {
+		return "Failed to connect to port";
+	}
+
+	Debug(driver, 2, "ALSA MIDI: opened sequencer port {}", this->seq_port);
+
+	this->InitMidiVolume();
+
+	return std::nullopt;
+}
+
+void MusicDriver_AlsaMidi::Stop()
+{
+	Debug(driver, 2, "ALSA MIDI: stopping");
+	this->StopSong();
+
+	if (this->queue_id) {
+		Debug(driver, 2, "ALSA MIDI: freeing sequencer event queue");
+		snd_seq_free_queue(this->seq, this->queue_id);
+	}
+
+	if (this->seq) {
+		Debug(driver, 2, "ALSA MIDI: closing sequencer handle");
+		snd_seq_close(this->seq);
+	}
+}
+
+void MusicDriver_AlsaMidi::PlaySong(const MusicSongInfo &song)
+{
+	Debug(driver, 2, "ALSA MIDI: PlaySong");
+	std::string filename = MidiFile::GetSMFFile(song);
+	smf::MidiFile midifile;
+
+	Debug(driver, 2, "ALSA MIDI: reading SMFFile");
+	if (!filename.empty()) {
+		if (!midifile.read(filename)) {
+			Debug(driver, 2, "ALSA MIDI: error reading SMFFile");
+		}
+	}
+
+	// Sort
+	midifile.sortTracks();
+	// Convert MIDI ticks to absolute seconds
+	midifile.doTimeAnalysis();
+
+	// Merge > 1 tracks into single track for easier queueing.
+	// (WriteSMF only creates single-track MIDIs, other packs may be multitrack)
+	midifile.joinTracks();
+
+	if (this->playing.load() == true) {
+		this->StopSong();
+	}
+
+	Debug(driver, 2, "ALSA MIDI: starting playback of {}", song.songname);
+	Debug(driver, 2, "ALSA MIDI: SMF filename {}", filename);
+
+	// ALSA does not allow setting PPQ on started queues, so do this first.
+	// Tempo may be adjusted later, on a started/running queue.
+	int ppq = midifile.getTPQ();
+	this->SetPPQ(ppq);
+
+	this->SetupPolling();
+
+	snd_seq_start_queue(this->seq, this->queue_id, nullptr);
+	snd_seq_drain_output(this->seq);
+
+	this->playing.store(true);
+
+	StartNewThread(&this->_queue_thread, "ottd:alsamidi", &StartQueue, this, std::move(midifile));
+}
+
+void MusicDriver_AlsaMidi::SetupPolling()
+{
+	int poll_fd_cnt = snd_seq_poll_descriptors_count(this->seq, POLLOUT);
+	this->poll_fds.resize(poll_fd_cnt);
+	snd_seq_poll_descriptors(this->seq, this->poll_fds.data(), poll_fd_cnt, POLLOUT);
+}
+
+/**
+ * Starts the ALSA sequencer queue, iterates through the MIDI events in the file,
+ * converts them to ALSA sequencer events, and pushes them onto the queue.
+ *
+ * This function is blocking and expects to be run in a thread. It will block
+ * until either it is signaled to stop (in which case it will purge the ALSA queue,
+ * send a GM RESET, and terminate), or it has enqueued all events in the MIDI file,
+ * and waited for the queue to finish processing them all.
+ *
+ * @param drv Pointer to `this` instance of the class
+ * @param midifile The previously-loaded, sorted, and time-corrected STD MIDI file.
+ *
+ * @see Stopping()
+ * @see StopSong()
+ * @see WaitForFinish()
+ */
+static void StartQueue(MusicDriver_AlsaMidi *drv, const smf::MidiFile midifile)
+{
+	Debug(driver, 2, "ALSA MIDI: queue thread started");
+
+	unsigned int last_tick;
+
+	// Push all events for all tracks to the sequencer queue
+	for (int track = 0; track < midifile.getNumTracks(); track++) {
+
+		std::vector<uint8_t> sysex_buffer;
+
+		for (int event = 0; event < midifile[track].size(); event++) {
+
+			auto& ev = midifile[track][event];
+
+			last_tick = static_cast<unsigned int>(ev.tick);
+
+			if (drv->Stopping())  {
+				Debug(driver, 2, "ALSA MIDI: Looks like we are stopping, bailing out of queue thread");
+				drv->SendResetEvent();
+				drv->StopQueue();
+				sysex_buffer.clear();
+				return;
+			}
+			if (ev.isTempo()) {
+				// Handle tempo change here,  as we have to change it for the whole queue
+				Debug(driver, 2, "ALSA MIDI: Got tempo change event in queue thread");
+				int tempo_uspq = ev.getTempoMicroseconds();
+				drv->UpdateTempo(tempo_uspq);
+				continue;
+			}
+			// Handle SYSEX events
+			// SYSEX events may
+			// 1. Be a complete SYSEX event (begin with F0 and end with F7)
+			// 2. Be a "middle" SYSEX event (a previous message began with F0)
+			// 3. Be an "end" SYSEX event (a previous message began with F0, and this one ends with F7)
+			// This basically means you need an accumulator. Split SYSEX messages are *rare* but exist.
+			if (ev.getCommandByte() == MIDIST_SYSEX) {
+				Debug(driver, 2, "ALSA MIDI: got SYSEX message");
+				sysex_buffer.clear();
+
+				// If this is is a complete (not partial) SYSEX message, send it
+				// Otherwise, accumulate it as a partial and continue to the next
+				if (ev.back() == MIDIST_ENDSYSEX) {
+					Debug(driver, 2, "ALSA MIDI: complete SYSEX, sending");
+					sysex_buffer.insert(sysex_buffer.end(), ev.begin() + 1, ev.end() -1);
+					drv->SendSysexEvent(sysex_buffer);
+					sysex_buffer.clear();
+				} else {
+					sysex_buffer.insert(sysex_buffer.end(), ev.begin() + 1, ev.end());
+				}
+				continue;
+			}
+			if (!sysex_buffer.empty() && ev.back() == MIDIST_ENDSYSEX) {
+				Debug(driver, 2, "ALSA MIDI: partial SYSEX completed, sending");
+				sysex_buffer.insert(sysex_buffer.end(), ev.begin(), ev.end() -1);
+				drv->SendSysexEvent(sysex_buffer);
+				sysex_buffer.clear();
+				continue;
+			}
+			if (!sysex_buffer.empty()) {
+				Debug(driver, 2, "ALSA MIDI: partial SYSEX continuing");
+				sysex_buffer.insert(sysex_buffer.end(), ev.begin(), ev.end());
+				continue;
+			}
+
+			// At this point, it's just a regular event - handle it.
+			drv->SendEvent(ev);
+		}
+	}
+
+	Debug(driver, 2, "ALSA MIDI: queue thread finished, waiting for events");
+	drv->WaitForFinish(last_tick);
+	drv->StopQueue();
+}
+
+/**
+ * Stops the ALSA sequencer queue, and sets `playing` to false.
+ *
+ * Note that this does not clear or drop any pending events in the queue
+ * before stopping it.
+ *
+ * @see SendResetEvent()
+ */
+void MusicDriver_AlsaMidi::StopQueue()
+{
+	Debug(driver, 2, "ALSA MIDI: stopping current queue!");
+	snd_seq_stop_queue(this->seq, this->queue_id, nullptr);
+	snd_seq_drain_output(this->seq);
+
+	this->poll_fds.clear();
+
+	this->playing.store(false);
+}
+
+/**
+ * Sends a SYSEX GM reset message, after dropping all pending events  in the
+ * queue.
+ *
+ * Does not stop the queue.
+ *
+ * @see StopQueue()
+ */
+void MusicDriver_AlsaMidi::SendResetEvent()
+{
+	// Drop anything still in the queue, this is a disruptive reset.
+	snd_seq_drop_output(this->seq);
+
+	std::vector<unsigned char> sysex_rst_msg = {0x7E, 0x7F, 0x09, 0x01};
+	this->SendSysexEvent(sysex_rst_msg);
+}
+
+/**
+ * Generic helper for sending SYSEX messages.
+ *
+ * Note that this sends all SYSEX messages as "direct"/unscheduled events
+ * (skips tick queue).
+ *
+ * @param data The SYSEX message data (excluding 0xF0/0xF7 begin/end markers).
+ *
+ * @see SendEvent()
+ */
+void MusicDriver_AlsaMidi::SendSysexEvent(const std::vector<uint8_t> data)
+{
+		snd_seq_event_t seqev;
+		snd_seq_ev_clear(&seqev);
+		snd_seq_ev_set_source(&seqev, this->seq_port);
+		snd_seq_ev_set_subs(&seqev);
+
+		std::vector<uint8_t> complete_message;
+		complete_message.reserve(data.size() + 2);
+		complete_message.push_back(0xF0);  // Start of SysEx
+		complete_message.insert(complete_message.end(), data.begin(), data.end());
+		complete_message.push_back(0xF7);  // End of SysEx
+		snd_seq_ev_set_sysex(&seqev, complete_message.size(), complete_message.data());
+
+		// TODO this assumes all SYSEX msgs are immediate, and not queued with a tick
+		// this is correct for SYSEX GM RESET (all this is currently used for) but
+		// might not be globally correct.
+		snd_seq_ev_set_direct(&seqev);
+
+		this->PushEvent(seqev);
+}
+
+/**
+ * Generic helper for sending non-SYSEX messages.
+ *
+ * Converts MIDI events from the file into ALSA-specific sequencer queue events,
+ * and schedules them on the tick-based sequencer queue.
+ *
+ * @param ev The raw MIDI event from the file.
+ *
+ * @see SendSysexEvent()
+ */
+void MusicDriver_AlsaMidi::SendEvent(const smf::MidiEvent& ev)
+{
+		snd_seq_event_t seqev;
+		snd_seq_ev_clear(&seqev);
+
+		unsigned int ticks = static_cast<unsigned int>(ev.tick);
+
+		if (ev.isNoteOn()) {
+			snd_seq_ev_set_noteon(&seqev, ev.getChannel(), ev[1], ev[2]);
+		} else if (ev.isNoteOff()) {
+			snd_seq_ev_set_noteoff(&seqev, ev.getChannel(), ev[1], ev[2]);
+		} else if (ev.isController()) {
+			if (ev[1] == MIDI_CTL_MSB_MAIN_VOLUME) {
+				this->UpdateChannelVolume(ev.getChannel(), ev[2]);
+				snd_seq_ev_set_controller(&seqev, ev.getChannel(), ev[1], this->vol_state.current_volume[ev.getChannel()]);
+			}
+			snd_seq_ev_set_controller(&seqev, ev.getChannel(), ev[1], ev[2]);
+		} else if (ev.isPatchChange()) {
+			snd_seq_ev_set_pgmchange(&seqev, ev.getChannel(), ev[1]);
+		} else if (ev.isPitchbend()) {
+			snd_seq_ev_set_pitchbend(&seqev, ev.getChannel(), ((ev[2] << 7) | ev[1]) - 8192);
+		} else if (ev.isPressure()) {
+			snd_seq_ev_set_chanpress(&seqev, ev.getChannel(), ev[1]);
+		} else if (ev.isAftertouch()) {
+			snd_seq_ev_set_keypress(&seqev, ev.getChannel(), ev[1], ev[2]);
+		} else if (ev.getCommandNibble() == 0xF0 && ev.getCommandByte() == MIDIST_SYSRESET) {
+			Debug(driver, 2, "ALSA MIDI: reset event");
+			snd_seq_ev_set_fixed(&seqev);
+			seqev.type = SND_SEQ_EVENT_RESET;
+		} else if (ev.isMeta()) {
+			Debug(driver, 2, "ALSA MIDI: ignoring meta message");
+			return;
+		} else {
+			Debug(driver, 2, "ALSA MIDI: unknown message: {}", ev.getCommandNibble());
+			return;
+		}
+
+		// Schedule event
+		snd_seq_ev_schedule_tick(&seqev, this->queue_id, 0, ticks);
+		snd_seq_ev_set_source(&seqev, this->seq_port);
+		snd_seq_ev_set_subs(&seqev);
+
+		this->PushEvent(seqev);
+}
+
+/**
+ * Waits until either:
+ *
+ * 1. The ALSA sequencer finishes processing up to the last event
+ * that was enqueued, as measured by comparing the tick value of the
+ * last event against the current tick value of the ALSA queue state.
+ *
+ * 2. `Stopping()` returns true, signaling early exit (don't wait for playback to finish).
+ *
+ * @param last_event_tick Tick value of the last event that was added to the queue.
+ *
+ * @see Stopping()
+ */
+void MusicDriver_AlsaMidi::WaitForFinish(const unsigned int last_event_tick)
+{
+	Debug(driver, 2, "ALSA MIDI: waiting for events finish");
+
+	// First wait for queue to drain
+	int res = 0;
+	do {
+		res = snd_seq_drain_output(this->seq);
+		if (res != 0) {
+			std::this_thread::sleep_for(std::chrono::milliseconds(10));
+		}
+	} while (res != 0);
+
+	// Now get queue status and wait until we've passed the last scheduled tick
+	snd_seq_queue_status_t *status;
+	snd_seq_queue_status_alloca(&status);
+
+	do {
+		snd_seq_get_queue_status(this->seq, this->queue_id, status);
+		const snd_seq_tick_time_t current_tick = snd_seq_queue_status_get_tick_time(status);
+
+		if (this->Stopping()) {
+			Debug(driver, 2, "ALSA MIDI: got stop signal, not waiting for events to finish");
+			this->SendResetEvent();
+			break;
+		}
+
+		if (current_tick >= last_event_tick) {
+			// This is necessarily imprecise, just because the queue has processed the last
+			// tick event doesn't mean whatever output device in use has played it yet,
+			// but in practice this is good enough to not cut off the last few notes.
+			std::this_thread::sleep_for(std::chrono::milliseconds(500));
+			break;
+		}
+		std::this_thread::sleep_for(std::chrono::milliseconds(10));
+	} while(true);
+
+	Debug(driver, 2, "ALSA MIDI: events finished");
+}
+
+/**
+ * Pushes an ALSA sequencer event onto the ALSA sequencer queue.
+ *
+ * If the push fails because the output buffer is full, uses `poll()`
+ * to wait until there's space/device is ready.
+ *
+ * @param seqev ALSA sequencer event to push.
+ */
+void MusicDriver_AlsaMidi::PushEvent(snd_seq_event_t seqev)
+{
+	// Wait for space in the queue via `poll()`
+	while (snd_seq_event_output_direct(this->seq, &seqev) < 0) {
+		poll(this->poll_fds.data(), this->poll_fds.size(), 100); // 100ms timeout
+	}
+}
+
+/**
+ * Signals the queue thread to terminate and joins it.
+ */
+void MusicDriver_AlsaMidi::StopSong()
+{
+	this->stopping.store(true);
+
+	Debug(driver, 2, "ALSA MIDI: StopSong waiting for queue thread");
+	if (this->_queue_thread.joinable()) {
+		this->_queue_thread.join();
+	}
+
+	Debug(driver, 2, "ALSA MIDI: stopping current queue");
+
+	this->stopping.store(false);
+
+	Debug(driver, 2, "ALSA MIDI: stopped song");
+}
+
+bool MusicDriver_AlsaMidi::Stopping()
+{
+	return this->stopping.load();
+}
+
+bool MusicDriver_AlsaMidi::IsSongPlaying()
+{
+	return this->playing.load();
+}
+
+/**
+ * Sets the desired volume for the MIDI sequencer (from the UI thread)
+ *
+ * Note that this implementation will internally debounce rapid subsequent calls to
+ * SetVolume(), to avoid overwhelming the sequencer and its queues and buffers with
+ * incremental volume updates. The magnitude of the volume change is taken into account
+ * for this.
+ *
+ */
+void MusicDriver_AlsaMidi::SetVolume(uint8_t vol)
+{
+	Debug(driver, 2, "ALSA MIDI: got volume level update {}", vol);
+
+	// Adaptive debounce: small changes need more time between updates
+    auto now = std::chrono::steady_clock::now();
+    auto elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(now - this->last_volume_update);
+
+    int current_vol = this->current_vol.load();
+    int change_magnitude = std::abs(vol - current_vol);
+
+	int required_ms = change_magnitude < 5 ? SMALL_VOL_DEBOUNCE :
+					   change_magnitude < 15 ? MED_VOL_DEBOUNCE :
+					   LARGE_VOL_DEBOUNCE;
+
+
+  if (elapsed.count() >= required_ms || current_vol == 127) {
+		Debug(driver, 2, "ALSA MIDI: got volume level update {}", vol);
+		if (vol != current_vol) {
+			this->SetScaledVolume(vol);
+			this->last_volume_update = now;
+		}
+	}
+}
+
+/**
+ * Initializes the volume state for the player.
+ *
+ * @see UpdateChannelVolume()
+ * @see SetScaledVolume()
+ */
+void MusicDriver_AlsaMidi::InitMidiVolume()
+{
+    this->last_volume_update = std::chrono::steady_clock::now();
+
+	this->vol_state.master_scale = 127;
+	for (int i = 0; i < MIDI_CHANNELS; i++) {
+		this->vol_state.base_volume[i] = 127;
+		this->vol_state.current_volume[i] = 127;
+	}
+}
+
+/**
+ * Scales current volume level for each channel according to the scale
+ * factor provided. This is to maintain the relative volume levels between
+ * channels as set by the midi file, while scaling up or down.
+ *
+ * @param channel to update the volume for.
+ * @param value requested volume level to scale selected channel volume against.
+ */
+void MusicDriver_AlsaMidi::UpdateChannelVolume(int channel, int value)
+{
+	std::lock_guard<std::mutex> lock(this->vol_state.mutex);
+	this->vol_state.base_volume[channel] = value;
+	this->vol_state.current_volume[channel] = (value * this->vol_state.master_scale) / 127;
+	Debug(driver, 2, "ALSA MIDI: upading volume for channel {} to {}, base: {}, scale {}", channel, this->vol_state.current_volume[channel], this->vol_state.base_volume[channel], this->vol_state.master_scale);
+}
+
+/**
+ * Scales current volume level for each channel according to the scale
+ * factor provided. This is to maintain the relative volume levels between
+ * channels as set by the midi file, while scaling up or down.
+ *
+ * @param value requested volume level (0-127) to scale all channel volume levels against.
+ */
+void MusicDriver_AlsaMidi::SetScaledVolume(int value)
+{
+	std::lock_guard<std::mutex> lock(this->vol_state.mutex);
+	this->vol_state.master_scale = (value > 127) ? 127 : (value < 0) ? 0 : value;
+
+	for (int i = 0; i < MIDI_CHANNELS; i++) {
+		this->vol_state.current_volume[i] = ( this->vol_state.base_volume[i] *  this->vol_state.master_scale) / 127;
+		snd_seq_event_t vol_ev;
+		snd_seq_ev_clear(&vol_ev);
+		Debug(driver, 2, "ALSA MIDI: setting volume for channel {} to {}, master: {} base: {}", i, this->vol_state.current_volume[i], this->vol_state.master_scale, this->vol_state.base_volume[i]);
+		snd_seq_ev_set_controller(&vol_ev, i, MIDI_CTL_MSB_MAIN_VOLUME,  this->vol_state.current_volume[i]);
+		snd_seq_ev_set_source(&vol_ev, this->seq_port);
+		snd_seq_ev_set_subs(&vol_ev);
+		snd_seq_ev_set_direct(&vol_ev);
+		this->PushEvent(vol_ev);
+	}
+
+	this->current_vol.store(value);
+}
+
+/**
+ * Updates the tempo of the current (started) ALSA sequencer queue.
+ *
+ * @param tempo_uspq Tempo value in units per quarter note.
+ */
+void MusicDriver_AlsaMidi::UpdateTempo(const int tempo_uspq)
+{
+	if (snd_seq_change_queue_tempo(this->seq, this->queue_id, tempo_uspq, nullptr) < 0) {
+		throw std::runtime_error("Failed to update queue tempo");
+	}
+	snd_seq_drain_output(this->seq);
+}
+
+/**
+ * Updates the Pulses Per Quarternote (PPQ) of the current ALSA sequencer queue.
+ *
+ * Note that the PPQ of an ALSA sequencer queue cannot be changed after it is started.
+ *
+ * @param ppq Pulse per quarter note value.
+ *
+ * @see StopQueue()
+ */
+void MusicDriver_AlsaMidi::SetPPQ(const int ppq)
+{
+	Debug(driver, 2, "ALSA MIDI: setting PPQ to {}", ppq);
+	snd_seq_queue_tempo_t* tempo;
+	snd_seq_queue_tempo_alloca(&tempo);
+	snd_seq_queue_tempo_set_ppq(tempo, ppq);
+	snd_seq_queue_tempo_set_tempo(tempo, 1000000); // 60 BPM
+
+	snd_seq_queue_status_t *status;
+	snd_seq_queue_status_alloca(&status);
+	snd_seq_get_queue_status(seq, queue_id, status);
+
+	if (snd_seq_queue_status_get_status(status) == 0) {
+		if (snd_seq_set_queue_tempo(this->seq, this->queue_id, tempo) < 0) {
+			throw std::runtime_error("Failed to set queue PPQ");
+		}
+		snd_seq_drain_output(this->seq);
+	} else {
+			Debug(driver, 2, "ALSA MIDI: tried to set PPQ on non-stopped queue!");
+	}
+}

src/music/alsamidi.h

@@ -0,0 +1,93 @@
+/*
+ * This file is part of OpenTTD.
+ * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
+ * OpenTTD 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 General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** @file alsamidi.h Base of Alsa MIDI support. */
+
+#ifndef MUSIC_ALSAMIDI_H
+#define MUSIC_ALSAMIDI_H
+
+#include "music_driver.hpp"
+#include <alsa/asoundlib.h>
+#include "../3rdparty/midifile/MidiFile.h"
+#include "../../thread.h"
+#include <atomic>
+
+const int SMALL_VOL_DEBOUNCE = 200; // Tiny changes: 200ms
+const int MED_VOL_DEBOUNCE = 50; // Small changes: 50ms
+const int LARGE_VOL_DEBOUNCE = 10; // Large changes: 10ms
+
+/** The midi player for ALSA on Linux. */
+class MusicDriver_AlsaMidi : public MusicDriver {
+public:
+	std::optional<std::string_view> Start(const StringList &param) override;
+
+	void Stop() override;
+
+	void PlaySong(const MusicSongInfo &song) override;
+
+	void StopSong() override;
+
+	bool IsSongPlaying() override;
+
+	void SetVolume(uint8_t vol) override;
+
+	std::string_view GetName() const override { return "alsamidi"; }
+
+	void WaitForFinish(const unsigned int last_tick);
+
+	void StopQueue();
+
+	void SendEvent(const smf::MidiEvent& event);
+
+	void SendSysexEvent(const std::vector<uint8_t> data);
+
+	void SendResetEvent();
+
+	void UpdateTempo(const int tempo_uspq);
+
+	bool Stopping();
+
+
+private:
+	typedef struct
+	{
+		int base_volume[MIDI_CHANNELS];
+		int master_scale;
+		int current_volume[MIDI_CHANNELS];
+		std::mutex mutex;
+	}MidiVolume;
+
+	MidiVolume vol_state;
+	snd_seq_t* seq;
+	int queue_id;
+	int seq_port;
+	int dev_port;
+	std::vector<struct pollfd> poll_fds;
+	std::thread _queue_thread;
+	std::atomic<bool> playing{false};
+	std::atomic<bool> stopping{false};
+	std::atomic<uint8_t> current_vol{127};
+	std::chrono::time_point<std::chrono::steady_clock> last_volume_update;
+	void SetPPQ(const int ppq);
+	void SetScaledVolume(int value);
+	void SetupPolling();
+	void PushEvent(snd_seq_event_t seqev);
+	void InitMidiVolume();
+	void UpdateChannelVolume(int channel, int value);
+	void VolumeAdjust (const uint8_t new_vol);
+};
+
+/** Factory for the Linux ALSA midi player. */
+class FMusicDriver_AlsaMidi : public DriverFactoryBase {
+public:
+	FMusicDriver_AlsaMidi() : DriverFactoryBase(Driver::DT_MUSIC, 10, "alsamidi", "ALSA Linux MIDI Driver") {}
+	Driver *CreateInstance() const override { return new MusicDriver_AlsaMidi(); }
+};
+
+static void StartQueue(MusicDriver_AlsaMidi *drv, const smf::MidiFile midifile);
+
+#endif /* MUSIC_ALSAMIDI_H */