DBreeze.Storage.FSR.FlushRandomBuffer C# (CSharp) Method

        void FlushRandomBuffer()
        {
            if (_randBuf.Count() == 0)
            {
                return;
            }

            //First we write all data into rollback file and helper, calling flush on rollback
            //then updating data of data file but dont call update
            //clearing random buffer

            //Creating rollback header
            byte[] offset = null;
            byte[] btRoll = null;

            bool flushRollback = false;

            //first loop for saving rollback data
            foreach (var de in _randBuf.OrderBy(r => r.Key))
            {
                offset = ((ulong)de.Key).To_8_bytes_array_BigEndian().Substring(8 - DefaultPointerLen, DefaultPointerLen);

                if (_rollbackCache.ContainsKey(de.Key))
                    continue;

                //Reading from dataFile values which must be rolled back
                btRoll = new byte[de.Value.Length];

                _fsData.Position = de.Key;
                _fsData.Read(btRoll, 0, btRoll.Length);
                //Console.WriteLine("2;{0};{1}", de.Key, ((btRoll == null) ? -1 : btRoll.Length));

                //Forming protocol for rollback
                btRoll = new byte[] { 1 }
                           .ConcatMany(
                           offset,
                           ((uint)btRoll.Length).To_4_bytes_array_BigEndian(),
                           btRoll
                           );

                //Writing rollback
                _fsRollback.Position = eofRollback;
                _fsRollback.Write(btRoll, 0, btRoll.Length);

                if (_backupIsActive)
                {
                    this._configuration.Backup.WriteBackupElement(ulFileName, 1, eofRollback, btRoll);
                }

                _rollbackCache.Add(de.Key, new r { o = eofRollback + 1 + offset.Length + 4, l = de.Value.Length });

                //increasing eof rollback file
                eofRollback += btRoll.Length;

                flushRollback = true;
            }

            if (flushRollback)
            {

                //Flushing rollback
                NET_Flush(_fsRollback);

                //Writing into helper
                _fsRollbackHelper.Position = 0;
                _fsRollbackHelper.Write(eofRollback.To_8_bytes_array_BigEndian(), 0, 8);

                //Flushing rollback helper
                NET_Flush(_fsRollbackHelper);

                if (_backupIsActive)
                {
                    this._configuration.Backup.WriteBackupElement(ulFileName, 2, 0, eofRollback.To_8_bytes_array_BigEndian());
                    this._configuration.Backup.Flush();
                }
            }

            //second loop for saving data
            foreach (var de in _randBuf.OrderBy(r => r.Key))      //sorting can mean nothing here, only takes extra time
            {
                _fsData.Position = de.Key;
                _fsData.Write(de.Value, 0, de.Value.Length);

                if (_backupIsActive)
                {
                    this._configuration.Backup.WriteBackupElement(ulFileName, 0, de.Key, de.Value);
                }
            }

            //No flush of data file, it will be done on Flush()

            _randBuf.Clear();
            usedBufferSize = 0;
        }