压缩和解压缩OLEVARIANT

uses ZLibEx

 

procedure VariantToStream(const V: OLEVariant; Stream: TStream);
var
  P : Pointer;
begin
  Stream.Position := 0;
  Stream.Size := VarArrayHighBound (V, 1) - VarArrayLowBound (V, 1) + 1;
  P := VarArrayLock (V);
  Stream.Write (P^, Stream.Size);
  VarArrayUnlock (V);
  Stream.Position := 0;
end;

 

procedure StreamToVariant(Stream: TStream; var V: OLEVariant);
var
  P : Pointer;
begin
  V := VarArrayCreate ([0, Stream.Size - 1], varByte);
  P := VarArrayLock (V);
  Stream.Position := 0;
  Stream.Read (P^, Stream.Size);
  VarArrayUnlock (V);
end;

 

function CompressData(V: OleVariant): OleVariant;
var
  M, M0: TMemoryStream;
begin
  M := TMemoryStream.Create;
  M0 := TMemoryStream.Create;
  try
    if V = Null then exit;

    VariantToStream(V,M);       //转换到流
    M.Position := 0;
    ZCompressStream(M, M0);        //压缩流
    StreamToVariant(M0, V);      //转换到变体返回值
  finally
    M.Free;
    M0.Free
  end;
  Result := V;
end;

 

function DeCompressData(V: OleVariant): OleVariant;
var
  M, M0: TMemoryStream;
begin
  M := TMemoryStream.Create;
  M0 := TMemoryStream.Create;
  try
    if V = Null then exit;

    VariantToStream(V,M);       //转换到流
    M.Position := 0;
    ZDeCompressStream(M, M0);        //压缩流
    StreamToVariant(M0, V);      //转换到变体返回值
  finally
    M.Free;
    M0.Free
  end;
  Result := V;
end;