added logging module and a sandbox project

include/matador/logger/rotating_file_sink.hpp

@@ -0,0 +1,82 @@
+#ifndef MATADOR_ROTATING_FILE_SINK_HPP
+#define MATADOR_ROTATING_FILE_SINK_HPP
+
+#include "matador/logger/log_sink.hpp"
+#include "matador/utils/file.hpp"
+
+#include <string>
+
+namespace matador::logger {
+
+/**
+ * @brief A rotating log file sink
+ *
+ * This log sink provides a possibility to
+ * rotate several log files if the current
+ * log file reaches the maximum size.
+ *
+ * The user can define the maximum number of log files
+ * and the maximum size of the current log file
+ *
+ * The name of the current log file is defined within the
+ * given logfile path. Each rotated (moved) log file gets
+ * an incremented number extension right before the
+ * file extension, e.g.:
+ *
+ * Log file name is 'log.txt' the first rotated log file
+ * is named 'log-1.txt' and so on until the maximum
+ * number of log files is reached. Then it starts from
+ * the beginning.
+ * Keep in mind that the log file to which is currently
+ * written to is always named like the file name
+ * given within the path.
+ */
+class rotating_file_sink final : public log_sink
+{
+public:
+  /**
+   * Creates a rotating log file sink within the given path
+   * with the given maximum number of rotating log files where
+   * each file size is never greater than the given max file
+   * size.
+   *
+   * @param path Path of the log file
+   * @param max_size Max log file size
+   * @param file_count Max log file count
+   */
+  rotating_file_sink(const std::string& path, size_t max_size, size_t file_count);
+
+  /**
+   * Write the message to the current log file. If the
+   * actual size exceeds the file size limit, the log files
+   * are rotated.
+   *
+   * @param message Message to write
+   * @param size The size of the log message
+   */
+  void write(const char *message, size_t size) override;
+
+  /**
+   * Close all open log files
+   */
+  void close() override;
+
+private:
+  std::string calculate_filename(size_t fileno);
+
+  void rotate();
+  void prepare(const std::string &path);
+
+private:
+  file logfile_;
+  std::string path_;
+  std::string base_path_;
+  std::string extension_;
+  size_t max_size_ = 0;
+  size_t current_size_ = 0;
+  size_t current_file_no_ = 0;
+  size_t file_count_ = 0;
+};
+
+}
+#endif //MATADOR_ROTATING_FILE_SINK_HPP