Deveel.Data.Store.ObjectStore.AddToRecordList C# (CSharp) Method

        private long AddToRecordList(long recordOffset)
        {
            lock (fixedList) {
                // If there is no free deleted records in the delete chain,
                if (firstDeleteChainRecord == -1) {
                    // Increase the size of the list structure.
                    fixedList.IncreaseSize();
                    // The start record of the new size
                    int newBlockNumber = fixedList.BlockCount - 1;
                    long startIndex = fixedList.BlockFirstPosition(newBlockNumber);
                    long sizeOfBlock = fixedList.BlockNodeCount(newBlockNumber);

                    // The IArea object for the new position
                    IArea a = fixedList.GetRecord(startIndex);

                    a.WriteInt4(0);
                    a.WriteInt4(0);
                    a.WriteInt8(-1);  // Initially unknown size
                    a.WriteInt8(0);	  // Initially unknown current size
                    a.WriteInt8(recordOffset);
                    // Set the rest of the block as deleted records
                    for (long n = 1; n < sizeOfBlock - 1; ++n) {
                        a.WriteInt4(DeletedFlag);
                        a.WriteInt4(0);
                        a.WriteInt8(-1);
                        a.WriteInt8(startIndex + n + 1);
                    }
                    // The last block is end of delete chain.
                    a.WriteInt4(DeletedFlag);
                    a.WriteInt4(0);
                    a.WriteInt8(-1);
                    a.WriteInt8(-1);
                    // Check out the changes.
                    a.Flush();

                    // And set the new delete chain
                    firstDeleteChainRecord = startIndex + 1;
                    fixedList.WriteDeleteHead(firstDeleteChainRecord);

                    // Return pointer to the record we just added.
                    return startIndex;

                }

                // Pull free block from the delete chain and recycle it.
                long recycledRecord = firstDeleteChainRecord;
                IArea block = fixedList.GetRecord(recycledRecord);
                var recordPos = block.Position;
                // Status of the recycled block
                int status = block.ReadInt4();
                if ((status & DeletedFlag) == 0)
                    throw new InvalidOperationException("Assertion failed: record is not deleted!");

                // Reference count (currently unused in delete chains).
                block.ReadInt4();
                // The size (should be -1);
                block.ReadInt8();
                // The current size should be 0
                block.ReadInt8();
                // The pointer to the next in the chain.
                long nextChain = block.ReadInt8();
                firstDeleteChainRecord = nextChain;

                // Update the first_delete_chain_record field in the header
                fixedList.WriteDeleteHead(firstDeleteChainRecord);

                // Update the block
                block.Position = recordPos;
                block.WriteInt4(0);
                block.WriteInt4(0);
                block.WriteInt8(-1);    // Initially unknown size
                block.WriteInt8(0);
                block.WriteInt8(recordOffset);

                // Check out the changes
                block.Flush();

                return recycledRecord;
            }
        }