public static void Decompress(FileInfo fi, ref Boolean[] columns)
        {
            Int32 bufferSize = 64*1024*1024; 
            string curFile = fi.FullName;
            string origName = curFile.Remove(curFile.Length -
                    fi.Extension.Length)+@".tmp";


            using (FileStream inFile = fi.OpenRead())
            {
                using (BufferedStream bufferedReadStream = new BufferedStream(inFile, bufferSize))
                {
                    using (GZipStream Decompress = new GZipStream(bufferedReadStream, CompressionMode.Decompress))
                    {
                            using (StreamReader sr = new StreamReader(Decompress))
                            {

                                using (FileStream fo = new FileStream(origName, FileMode.Create))
                                {
                                    //using (BufferedStream bufferedWriteStream = new BufferedStream(fo, bufferSize))
                                    //{

                                        using (StreamWriter outFile = new StreamWriter(fo))
                                        {

                                            
                                            while (sr.Peek() >= 0)
                                            {
                                                outFile.Write(csv_remove_unused_data(sr.ReadLine(),'|',ref columns) + "\n");
                                            }

                                            //bufferedWriteStream.Flush();

                                        }
                                    //}
                                }
                        


                        }
                    }
                }
            }