REFAC: remove trailing zeros and add UTC time identifier (Z) when printing...

REFAC: remove trailing zeros and add UTC time identifier (Z) when printing dates with a decimal second part

Modules/Core/Metadata/include/otbDateTime.h

@@ -102,7 +102,7 @@ public:
   TimePoint(): m_Time(InternalTimePointType::min()) {}
   TimePoint(InternalTimePointType const& t): m_Time(t) {}
 
-  std::ostream & Display(std::ostream & os, const std::string & format = details::timePointFormat) const;
+  std::ostream & Display(std::ostream & os) const;
   std::istream & Read   (std::istream & is, const std::string & format = details::timePointFormat);
 
   template <typename U, typename V> static U diff(V const& lhs, V const& rhs) 

Modules/Core/Metadata/src/otbDateTime.cxx

@@ -48,9 +48,16 @@ TimePoint ReadFormattedDate(const std::string & dateStr, const std::string & for
   return tp;
 }
 
-std::ostream & TimePoint::Display(std::ostream & os, const std::string& format) const 
+std::ostream & TimePoint::Display(std::ostream & os) const 
 {
-  date::to_stream(os, format.c_str(), m_Time);
+  auto dateStr = date::format( "%Y-%m-%dT%H:%M:%S", m_Time);
+
+  // date::format %S returns the number of seconds with a fixed size format (ns precision)
+  // Remove the trailing zeros in the output.
+  dateStr.erase(dateStr.find_last_not_of('0') + 1, std::string::npos);
+
+  // Add the UTC time identifier
+  os << dateStr << "Z";
   return os;
 }