[BL] added datetime formatting function

BaseLib/DateTools.cpp

@@ -16,6 +16,7 @@
 
 #include <cmath>
 #include <cstdlib>
+#include <ctime>
 #include <sstream>
 
 #include <logog/include/logog.hpp>
@@ -114,4 +115,17 @@ int xmlDate2int(const std::string &s)
     }
     return 0;
 }
+
+std::string formatDate(
+    std::chrono::time_point<std::chrono::system_clock> const& time)
+{
+    auto const time_t = std::chrono::system_clock::to_time_t(time);
+    char time_str[100];
+    if (std::strftime(time_str, sizeof(time_str), "%F %T%z",
+                      std::localtime(&time_t))) {
+        return time_str;
+    } else {
+        return "FAILED FORMATTING THE GIVEN TIME POINT.";
+    }
+}
 } // end namespace BaseLib

BaseLib/DateTools.h

@@ -15,9 +15,11 @@
 #ifndef DATETOOLS_H
 #define DATETOOLS_H
 
+#include <chrono>
 #include <string>
 
-namespace BaseLib {
+namespace BaseLib
+{
 
 /**
  * Converts three integers representing a date into a double.
@@ -55,6 +57,15 @@ int strDate2int(const std::string &s);
  */
 int xmlDate2int(const std::string &s);
 
+/**
+ * Formats the given time point according to RFC 3339 (cf. man-page of the unix
+ * date utility).
+ *
+ * Example: 2006-08-14 02:34:56-06:00
+ */
+std::string formatDate(
+    std::chrono::time_point<std::chrono::system_clock> const& time);
+
 } // namespace BaseLib
 
 #endif //DATETOOLS_H