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POOleVariant stream to TStringList optimization
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  1. POOleVariant stream to TStringList optimization
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    copied!<p>My server returns a string stream as OleVariant via a COM/DCOM call. This code works well for the client, but can probably be improved. Hints are welcome.</p> <p>And as a follow up, what if the server returns the OleVariant stream as UTF-8, what is the best way for the client to convert it to unicode ?</p> <pre><code>procedure TClientToServer.GetText( mode : integer; const infoText : widestring; txt : TStrings); var size : integer; dataP : pointer; data : OleVariant; strStream : TStringStream; begin txt.Clear; data:= fDComServer.GetData( mode,infoText); if VarIsNull(data) then Exit; size:= VarArrayHighBound(data,1) + 1; dataP:= VarArrayLock( data); try strStream:= TStringStream.Create; try strStream.Write( dataP^,size); strStream.Seek(0,0); txt.LoadFromStream( strStream); finally strStream.Free; end; finally VarArrayUnlock( data); end; end; </code></pre> <p>Edit : Going for UTF8 means that less bandwidth is used on the network, and I can reuse the COM/DCOM routines more or less intact when later implementing a http protocol interface based on UTF8 strings.</p> <p>Thanks David for pointing me in the right direction to trim the code a little bit.</p> <p>Here is the updated procedure :</p> <pre><code>procedure TClientToServer.GetText( mode : integer; const infoText : widestring; txt : TStrings); var size : integer; dataP : Pointer; data : OleVariant; utf8Str : Utf8String; begin txt.Clear; data:= fDComServer.GetData( mode,infoText); if VarIsNull(data) then Exit; size:= VarArrayHighBound(data,1) + 1; dataP:= VarArrayLock( data); try SetString( utf8Str, PAnsiChar(dataP), size); txt.Text:= utf8Str; finally VarArrayUnlock( data); end; end; </code></pre>
 

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