Saber se um arquivo compactado com zLib está normal.

var
  FileInName: TFileName;
  FileIn, FileOut: TFileStream;
  Zip: TCompressionStream;
  NumArquivos, I, Len, Size: Integer;
  Fim: Byte;
begin
  FileOut := TFileStream.Create(FileOutName, fmCreate or fmShareExclusive);
  Zip := TCompressionStream.Create( clMax, FileOut);
  NumArquivos := Length(Files);
  Zip.Write(NumArquivos, SizeOf(Integer));
  try
    for I := Low(Files) to High(Files) do
    begin
      FileIn := TFileStream.Create(Files[I], fmOpenRead and fmShareExclusive);
      try
        FileInName := ExtractFileName(Files[I]);
        Len := Length(FileInName);
        Zip.Write(Len, SizeOf(Integer));
        Zip.Write(FileInName[1], Len);
        Size := FileIn.Size;
        Zip.Write(Size, SizeOf(Integer));
        Zip.CopyFrom(FileIn, FileIn.Size);
        Fim := 0;
        Zip.Write(Fim, SizeOf(Byte));
      finally
        FileIn.Free;
      end;
    end;
  finally
   Zip.Free;
   FileOut.Free;
  end;
end;