diff -r 5b351628a377 -r 15d87fdd6e6c Logger.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Logger.cpp	Mon Jan 04 15:45:12 2021 +0100
@@ -0,0 +1,78 @@
+/**
+ * DJM-Fix
+ * Copyright © 2020 František Kučera (Frantovo.cz, GlobalCode.info)
+ *
+ * This program 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 3 of the License.
+ *
+ * This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <chrono>
+#include <iomanip>
+#include <sstream>
+
+#include "Logger.h"
+
+namespace djmfix {
+namespace logging {
+
+class Blackhole : public Logger {
+public:
+
+	virtual void log(Level level, const std::string& message) override {
+	}
+};
+
+class LoggerImpl : public Logger {
+private:
+	std::ostream& output;
+	Level minLevel;
+
+	std::string getTimestamp() {
+		auto now = std::chrono::system_clock::now();
+		auto itt = std::chrono::system_clock::to_time_t(now);
+		std::ostringstream ss;
+		ss << std::put_time(localtime(&itt), "%FT%T%z");
+		return ss.str();
+	}
+
+	std::string toString(Level level) {
+		if (level == Level::SEVERE) return "SEVERE";
+		else if (level == Level::WARNING) return "WARNING";
+		else if (level == Level::INFO) return "INFO";
+		else if (level == Level::CONFIG) return "CONFIG";
+		else if (level == Level::FINE) return "FINE";
+		else if (level == Level::FINER) return "FINER";
+		else if (level == Level::FINEST) return "FINEST";
+		else return "UNKNOWN";
+	}
+
+public:
+
+	LoggerImpl(std::ostream& output, Level minLevel) : output(output), minLevel(minLevel) {
+	}
+
+	virtual void log(Level level, const std::string& message) override {
+		if (level <= minLevel) {
+			output << getTimestamp() << " " << std::setw(8) << toString(level) << ":  " << message << std::endl;
+		}
+	}
+};
+
+Logger* create(std::ostream& output, Level minLevel) {
+	return new LoggerImpl(output, minLevel);
+}
+
+Logger* blackhole() {
+	return new Blackhole();
+}
+
+}
+}