gearmulator

commit 70fec21a8e418a59563ac9b0fe7cbd8b4e2d87ef
parent 82ad36aa39114ecf69b00ab336646883d460a49e
Author: dsp56300 <dsp56300@users.noreply.github.com>
Date:   Sun,  4 Dec 2022 02:33:19 +0100

implement SysEx to midi converter

Diffstat:
M
source/synthLib/CMakeLists.txt
 | 
1
+
A
source/synthLib/sysexToMidi.cpp
 | 
109
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
A
source/synthLib/sysexToMidi.h
 | 
21
+++++++++++++++++++++

3 files changed, 131 insertions(+), 0 deletions(-)
diff --git a/source/synthLib/CMakeLists.txt b/source/synthLib/CMakeLists.txt
@@ -13,6 +13,7 @@ set(SOURCES
 	plugin.cpp plugin.h
 	resampler.cpp resampler.h
 	resamplerInOut.cpp resamplerInOut.h
+	sysexToMidi.cpp sysexToMidi.h
 	wavWriter.cpp wavWriter.h
 )
 
diff --git a/source/synthLib/sysexToMidi.cpp b/source/synthLib/sysexToMidi.cpp
@@ -0,0 +1,109 @@
+#include "sysexToMidi.h"
+
+#include <fstream>
+
+namespace synthLib
+{
+	constexpr uint16_t g_ppq = 96;
+	constexpr uint16_t g_beatsBetweenMessages = 1;
+
+	bool SysexToMidi::write(const char* _filename, const std::vector<std::vector<uint8_t>>& _messages)
+	{
+		std::ofstream f(_filename, std::ios::binary);
+		if(!f.is_open())
+			return false;
+		try
+		{
+			write(f, _messages);
+		}
+		catch (...)
+		{
+			return false;
+		}
+		return true;
+	}
+
+	void SysexToMidi::write(std::ostream& _dst, const std::vector<std::vector<uint8_t>>& _messages)
+	{
+		write(_dst, "MThd");	// header
+		writeUInt32(_dst, 6);	// chunk length = 6
+		writeUInt16(_dst, 0);	// format = single multi-channel track
+		writeUInt16(_dst, 1);	// number of tracks = 1
+		writeUInt16(_dst, 96);	// ticks per quarter note = 96
+
+		// track chunk
+		write(_dst, "MTrk");
+		const auto trackChunkBegin = _dst.tellp();
+		writeUInt32(_dst, 0);		// will be replaced later
+
+		for (const auto& message : _messages)
+		{
+			writeVarLen(_dst, g_ppq * g_beatsBetweenMessages);				// delta time
+			writeUInt8(_dst, message.front());								// f0 comes first...
+			writeVarLen(_dst, static_cast<uint32_t>(message.size() - 1));		// ...then the length
+			_dst.write(reinterpret_cast<const char*>(&message[1]), static_cast<std::streamsize>(message.size() - 1));
+		}
+		const auto newPos = _dst.tellp();
+		const auto trackChunkLength = newPos - trackChunkBegin;
+
+		writeBuf(_dst, {0xff,0x2f,0x00});	// end of track
+
+		_dst.seekp(trackChunkBegin);
+		writeUInt32(_dst, static_cast<uint32_t>(trackChunkLength));
+	}
+
+	void SysexToMidi::writeBuf(std::ostream& _dst, const std::vector<uint8_t>& _data)
+	{
+		_dst.write(reinterpret_cast<const char*>(&_data[0]), static_cast<std::streamsize>(_data.size()));
+	}
+
+	void SysexToMidi::writeUInt8(std::ostream& _dst, uint8_t _data)
+	{
+		_dst.write(reinterpret_cast<const char*>(&_data), 1);
+	}
+
+	void SysexToMidi::writeUInt32(std::ostream& _dst, const uint32_t& _data)
+	{
+		writeBuf(_dst, 
+		{
+			static_cast<unsigned char>((_data >> 24) & 0xff),
+			static_cast<unsigned char>((_data >> 16) & 0xff),
+			static_cast<unsigned char>((_data >> 8) & 0xff),
+			static_cast<unsigned char>(_data & 0xff)
+		});
+	}
+
+	void SysexToMidi::writeUInt16(std::ostream& _dst, const uint16_t& _data)
+	{
+		writeBuf(_dst,
+		{
+			static_cast<unsigned char>((_data >> 8) & 0xff),
+			static_cast<unsigned char>(_data & 0xff)
+		});
+	}
+
+	void SysexToMidi::write(std::ostream& _dst, const std::string& _data)
+	{
+		_dst << _data;
+	}
+
+	void SysexToMidi::writeVarLen(std::ostream& _dst, uint32_t _len)
+	{
+		auto buffer = _len & 0x7f;
+
+		while ( (_len >>= 7) )
+		{
+			buffer <<= 8;
+			buffer |= ((_len & 0x7f) | 0x80);
+		}
+
+		while (true)
+		{
+			const auto byte = static_cast<uint8_t>(buffer & 0xff);
+			writeUInt8(_dst, byte);
+			if ((byte & 0x80) == 0)
+				break;
+			buffer >>= 8;
+		}
+	}
+}
diff --git a/source/synthLib/sysexToMidi.h b/source/synthLib/sysexToMidi.h
@@ -0,0 +1,21 @@
+#pragma once
+
+#include <ostream>
+#include <vector>
+
+namespace synthLib
+{
+	class SysexToMidi
+	{
+	public:
+		static bool write(const char* _filename, const std::vector<std::vector<uint8_t>>& _messages);
+		static void write(std::ostream& _dst, const std::vector<std::vector<uint8_t>>& _messages);
+	private:
+		static void writeBuf(std::ostream& _dst, const std::vector<uint8_t>& _data);
+		static void writeUInt8(std::ostream& _dst, uint8_t _data);
+		static void writeUInt32(std::ostream& _dst, const uint32_t& _data);
+		static void writeUInt16(std::ostream& _dst, const uint16_t& _data);
+		static void write(std::ostream& _dst, const std::string& _data);
+		static void writeVarLen(std::ostream& _dst, uint32_t _len);
+	};
+}