Tmemorystream, string, and olevariant

///////////////////////////////////// //////////////////////////////////////// ///
// function: the content of string is streamed to olevariant
// parameter:
///////////////////////////////////// //////////////////////////////////////// ///
function texttooledata (const atext: string): olevariant;
var
nsize: integer;
pdata: pointer;
begin
nsize: = length (atext );
If nsize = 0 then
result: = NULL
else begin
result: = vararraycreate ([0, nsize-1], varbyte );
pdata: = vararraylock (result);
try
move (pchar (atext) ^, pdata ^, nsize );
finally
vararrayunlock (result);
end;

//////////////////////////////////////// ////////////////////////////////////////
// Function: the string content is loaded by olevariant.
// Parameters:
//////////////////////////////////////// ////////////////////////////////////////
Function oledatatotext (const aData: olevariant): string;
VaR
Nsize: integer;
Pdata: pointer;
Begin
If aData = NULL then
Result: =''
Else begin
Nsize: = vararrayhighbound (aData, 1)-vararraylowbound (aData, 1) + 1;
Setlength (result, nsize );
Pdata: = vararraylock (aData );
Try
Move (pdata ^, pchar (result) ^, nsize );
Finally
Vararrayunlock (aData );
End;
End;
End;

 

// Convert olevariant and tmemorystream:
Function memorystreamtoolevariant (STRM: tmemorystream): olevariant;
VaR
Data: pbytearray;
Begin
Result: = vararraycreate ([0, STRM. Size-1], varbyte );
Data: = vararraylock (result );
Try
STRM. Position: = 0;
STRM. readbuffer (Data ^, STRM. size );
Finally
Vararrayunlock (result );
End;
End;

Function olevarianttomemorystream (OV: olevariant): tmemorystream;
VaR
Data: pbytearray;
Size: integer;
Begin
Result: = tmemorystream. Create;
Try
Size: = vararrayhighbound (OV, 1)-vararraylowbound (OV, 1) + 1;
Data: = vararraylock (OV );
Try
Result. Position: = 0;
Result. writebuffer (Data ^, size );
Finally
Vararrayunlock (OV );
End;
Except
Result. Free;
Result: = nil;
End;
End;

Function recordsettovariant (const recordset: _ recordset; var stream: olevariant): Boolean;
VaR
RS: olevariant;
Vdata: tmemorystream;
Begin
Result: = false;
If recordset = nil then exit;
Vdata: = tmemorystream. Create;
Try
RS: = createoleobject ('ADODB. recordset ');
RS: = recordset;
Rs. Save (tstreamadapter. Create (vdata) as iunknown, adpersistadtg );
Vdata. Position: = 0;
Result: = true;
Stream: = memorystreamtoolevariant (vdata );
Except
On E: exception do
Begin
RS: = E. message;
Stream: = RS;
Result: = false;
End;
End;
End;
Function recordsetfromvariant (vdata: olevariant): _ recordset;
VaR
RS: olevariant;
Stream: tmemorystream;
Begin
Result: = nil;
Stream: = tmemorystream. Create;
Stream: = olevarianttomemorystream (vdata );
If stream. Size <1 then exit;
Try
Stream. Position: = 0;
RS: = createoleobject ('ADODB. recordset ');
Rs. Open (tstreamadapter. Create (Stream) as iunknown );
Result: = iunknown (RS) AS _ recordset;
Finally;
End;
End;