added logging module and a sandbox project

include/matador/logger/basic_file_sink.hpp

@@ -0,0 +1,49 @@
+#ifndef MATADOR_BASIC_FILE_SINK_HPP
+#define MATADOR_BASIC_FILE_SINK_HPP
+
+#include "matador/logger/log_sink.hpp"
+
+namespace matador::logger {
+
+/**
+ * @brief A base class for the file-stream-based sinks
+ *
+ * This class acts like a base class for all
+ * concrete sinks working with a file stream to write
+ * the log message.
+ */
+class basic_file_sink : public log_sink
+{
+protected:
+  basic_file_sink() = default;
+
+  /**
+   * Creates a basic_file_sink with a given file stream
+   *
+   * @param f File stream to write on
+   */
+  explicit basic_file_sink(FILE *f);
+
+public:
+  /**
+   * Writes the log message to the internal
+   * file stream.
+   *
+   * @param message The message to write
+   * @param size The size of the message
+   */
+  void write(const char *message, size_t size) override;
+
+  /**
+   * Closes the internal file stream.
+   */
+  void close() override;
+
+protected:
+  /// @cond MATADOR_DEV
+  FILE *stream = nullptr;
+  /// @endcond
+};
+
+}
+#endif //MATADOR_BASIC_FILE_SINK_HPP