BlockSplitterMiddle.cs

using System;
 
namespace Waher.Persistence.Files.Storage
{
    internal class BlockSplitterMiddle : BlockSplitter
    {
        public int MiddlePos;
 
        public BlockSplitterMiddle(int PayloadSize)
            : base()
        {
            this.MiddlePos = PayloadSize / 2 + ObjectBTreeFile.BlockHeaderSize;    // Instead of median value, select the value residing in the middle of the block. These are not the same, since object values might be of different sizes.
        }
 
        public override void NextBlock(uint BlockLink, byte[] Block, int Pos, int Len, uint ChildSize)
        {
            int c = 4 + Len;
 
            if (!(this.ParentObject is null))
            {
                if (this.RightSizeSubtree < uint.MaxValue)
                {
                    this.RightSizeSubtree++;
 
                    this.RightSizeSubtree += ChildSize;
                    if (this.RightSizeSubtree < ChildSize)
                        this.RightSizeSubtree = uint.MaxValue;
                }
 
                Array.Copy(BitConverter.GetBytes(BlockLink), 0, RightBlock, RightPos, 4);
                this.RightPos += 4;
                Array.Copy(Block, Pos, RightBlock, RightPos, Len);
                this.RightPos += Len;
                this.TotPos += c;
            }
            else if (this.TotPos + c <= this.MiddlePos)
            {
                if (this.LeftSizeSubtree < uint.MaxValue)
                {
                    this.LeftSizeSubtree++;
 
                    this.LeftSizeSubtree += ChildSize;
                    if (this.LeftSizeSubtree < ChildSize)
                        this.LeftSizeSubtree = uint.MaxValue;
                }
 
                Array.Copy(BitConverter.GetBytes(BlockLink), 0, LeftBlock, LeftPos, 4);
                this.LeftPos += 4;
                Array.Copy(Block, Pos, LeftBlock, LeftPos, Len);
                this.LeftPos += Len;
                this.TotPos += c;
            }
            else 
            {
                this.LeftLastBlockIndex = BlockLink;
                this.LeftSizeSubtree += ChildSize;
                if (this.LeftSizeSubtree < ChildSize)
                    this.LeftSizeSubtree = uint.MaxValue;
 
                this.ParentObject = new byte[Len];
                Array.Copy(Block, Pos, this.ParentObject, 0, Len);
            }
        }
 
    }
}