FAQ-0442 How should I externalize/internalize a TDateTime?


FAQ-0442 How should I externalize/internalize a TDateTime?

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Classification:	C++	Category:	Streams & Stores
Created:	11/30/99	Modified:	09/11/2002
Number:	FAQ-0442
Platform:	Not Applicable

Question:
The TDateTime class is not store aware so does not support the >> and << operators. What is the best strategy to externalize/Internalize it?

Answer:
Convert it to a TTime, then to a TInt64 which can be externalized. For internalizing do the reverse.The following example code illustrates both:

_LIT(KTestExternalizeDateTime, "C:\\Documents\\DateTimeTest");
RFs fsSession; User::LeaveIfError(fsSession.Connect()); CFileStore* store = CDirectFileStore::ReplaceLC(fsSession, KTestExternalizeDateTime, EFileWrite); store->SetTypeL(KDirectFileStoreLayoutUid); RStoreWriteStream writeStream; TStreamId id = writeStream.CreateLC(*store); TDateTime myDateTime(1999, ENovember, 29, 11, 04, 00, 00); TTime myTime(myDateTime); writeStream << myTime.Int64(); writeStream.CommitL(); CleanupStack::PopAndDestroy(); // writeStream store->SetRootL(id); store->CommitL(); CleanupStack::PopAndDestroy(); // store store = CDirectFileStore::OpenLC(fsSession, KTestExternalizeDateTime, EFileRead); RStoreReadStream readStream; readStream.OpenLC(*store, store->Root()); TInt64 myInt64RepresentingDateTime; readStream >> myInt64RepresentingDateTime; CleanupStack::PopAndDestroy(2); //store + stream fsSession.Close(); TTime myTimeFromInt64(myInt64RepresentingDateTime);
TDateTime myRestoredDateTime = myTimeFromInt64.DateTime();