Problem with ZLibDecompressString

[matthewj]

Hi,

I'm just evaluating the VCLZip component (in Delphi 7), but am having a problem with ZLibDecompressString. The problem is that it isn't returning the result, but is instead altering the original string.
Perhaps this is fixed in 3.06, but the code below my signature shows the problem easily in the debugger. Set it up to show all the strings in the watch window, and then you will see at the marked line that the
result is very wrong.

I checked the forums but this is not mentioned. I look forward to a speedy response so I can complete my testing and buy it.

Yours,

Matthew Jones

procedure TestCoding;
var
  xZipper : TVCLZip;
  szDecoded : string;
  szFinal : string;
  szOriginal : String;
  szCompressed : string;
  szZipped : string;
begin
  szOriginal := 'hello mum how are you today';
  xZipper := TVCLZip.Create(nil);
  try
      szZipped := xZipper.ZLibCompressStr(szOriginal, false);
      szCompressed := EncodeLine(szZipped);
  finally
      FreeAndNil(xZipper);
  end;

  xZipper := TVCLZip.Create(nil);
  try
      szDecoded := DecodeLine(szCompressed);
      // breakpoint on the next line, and watch what happens to the
variables!
      szFinal := xZipper.ZLibDecompressString(szDecoded, false);
  finally
      FreeAndNil(xZipper);
  end;
  assert(szFinal = szOriginal);
end;


Oops - I forgot that the decode is needed. This is a base64 encoding so that I can store the text in XML. You can use the following and it still shows the problem:


  function EncodeLine(szValue : string) : string;
  begin
      result := szValue;
  end;
  function DecodeLine(szValue : string) : string;
  begin
      result := szValue;
  end;


Note also that the szDecoded string has original junk at the end. Looks
to me like the SetLength is used on the result, but the values written
to the parameter.

[Kevin]

Matthew,

I tested your code using VCLZip 3.06 and it worked fine.

Kevin