File Based Dictionary Store

Creating the dictionary store

This code fragment constructs an object of type TClass and stores it in the dictionary store, associating the stream with the UID whose value is 0x0002.

Note that a dictionary write stream is needed to write streams to a dictionary store.

       
        
       
       _LIT(KFileName,"C:\\data\\stdict.dat");
_LIT(KTxtData,"Text type data"):
TParse dictionaryname;
...
fsSession.Parse(KFileName,dictionaryname);
... 
           // Open the dictionary store (create if it doesn't exist)
CDictionaryStore* dictstore = CDictionaryFileStore::OpenLC (fsSession, dictionaryname.FullName(),TUid::Uid(0x0001) );

           // Construct a TClass and put some data into it
TClass thedata;
thedata.iFixBuf    = KTxtData;
thedata.iUintValue = 1;
thedata.iIntValue  = -2; 
thedata.iRealValue = 3.4;

           // construct the dictionary write stream and
           // associate the stream with the UID
           // whose value is 0x0002
RDictionaryWriteStream out;
out.AssignLC(*dictstore,TUid::Uid(0x0002));

           // write the TClass data to the stream
out << thedata;
 
           // Commit changes to the stream
out.CommitL(); 

           // Cleanup the dictionary stream object
CleanupStack::PopAndDestroy();

           // Now commit all changes to the store
dictstore->CommitL();

           // Close the dictionary store (closes the
           // associated file and destroys the 
           // dictionary store object)
CleanupStack::PopAndDestroy();
      

Reopening the dictionary store

This code fragment re-opens the dictionary store and restores the <code>TClass</code> object from the stream associated with the UID whose value is <code>0x0002</code>

       _LIT(KFileName,"C:\\data\\stdict.dat");
TParse dictionaryname;
...
fsSession.Parse(KFileName,dictionaryname);
...
           // Open the dictionary store 
CDictionaryStore* dictstore=CDictionaryFileStore::OpenLC(fsSession, dictionaryname.FullName(), TUid::Uid(0x0001) );

           // construct the dictionary read stream.
           // Prepare to read the stream associated with
           // the unique identifier whose value is 0x0002
RDictionaryReadStream in;
in.OpenLC(*dictstore,TUid::Uid(0x0002));

            // Construct a TClass object ...
TClass thedata;

            // ... and read data from the stream
in >> thedata;

            // Cleanup the dictionary stream object
            // and ...
            // Close the dictionary store
            // (closes the associated file and destroys the
            // dictionary store object)
CleanupStack::PopAndDestroy(2);