datalogger: allow logger to be reopened for simulation reset

Include/dpsim/DataLogger.h

@@ -24,6 +24,8 @@
 #include <map>
 #include <iostream>
 #include <fstream>
+#include <experimental/filesystem>
+namespace fs = std::experimental::filesystem;
 
 #include <dpsim/Definitions.h>
 #include <dpsim/Scheduler.h>
@@ -41,6 +43,7 @@ namespace DPsim {
 		String mName;
 		Bool mEnabled;
 		UInt mDownsampling;
+		fs::path mFilename;
 
 		std::map<String, CPS::AttributeBase::Ptr> mAttributes;
 
@@ -54,9 +57,13 @@ namespace DPsim {
 
 		DataLogger(Bool enabled = true);
 		DataLogger(String name, Bool enabled = true, UInt downsampling = 1);
-		~DataLogger();
 
+		void open();
 		void close();
+		void reopen() {
+			close();
+			open();
+		}
 
 		void logPhasorNodeValues(Real time, const Matrix& data);
 		void logEMTNodeValues(Real time, const Matrix& data);

Source/DataLogger.cpp

@@ -19,8 +19,6 @@
  *********************************************************************************/
 
 #include <iomanip>
-#include <experimental/filesystem>
-namespace fs = std::experimental::filesystem;
 
 #include <dpsim/DataLogger.h>
 #include <cps/Logger.h>
@@ -41,26 +39,23 @@ DataLogger::DataLogger(String name, Bool enabled, UInt downsampling) :
 	if (!mEnabled)
 		return;
 
-	String filename = CPS::Logger::logDir() + "/" + name + ".csv";
+	mFilename = CPS::Logger::logDir() + "/" + name + ".csv";
 
-	fs::path p = filename;
+	if (mFilename.has_parent_path() && !fs::exists(mFilename.parent_path()))
+		fs::create_directory(mFilename.parent_path());
 
-	if (p.has_parent_path() && !fs::exists(p.parent_path()))
-		fs::create_directory(p.parent_path());
+	open();
+}
 
-	mLogFile = std::ofstream(filename);
+void DataLogger::open() {
+	mLogFile = std::ofstream(mFilename, std::ios_base::out|std::ios_base::trunc);
 	if (!mLogFile.is_open()) {
 		// TODO: replace by exception
-		std::cerr << "Cannot open log file " << filename << std::endl;
+		std::cerr << "Cannot open log file " << mFilename << std::endl;
 		mEnabled = false;
 	}
 }
 
-DataLogger::~DataLogger() {
-	if (mLogFile.is_open())
-		mLogFile.close();
-}
-
 void DataLogger::close() {
 	mLogFile.close();
 }