private void AppendNewHead <T>(Dimension <T> dimension, SpacePoint <T> sp, float position)
        {
            var newHead = new DimensionPoint <T>(dimension)
            {
                Position = position
            };

            newHead.AddPoint(sp);
            newHead.HeadLink = new DimensionLink <T>(0, newHead);

            var oldHead = dimension.HeadDimPoint;

            dimension.HeadDimPoint = newHead;
            newHead.HeadLink.AssignNext(oldHead.HeadLink);

            var upper = oldHead.HeadLink.Upper;

            newHead.HeadLink.AssignUpper(upper);
            oldHead.HeadLink.Upper = null;
            newHead.TailLink       = oldHead.TailLink.Level == 0 ? newHead.HeadLink : oldHead.TailLink;
            oldHead.TailLink       = oldHead.HeadLink;

            _spaceManager.TryAddLevel(dimension);
            var toExtendUp = dimension.HeadDimPoint.HeadLink.NextUntil((n, i) => i == 1);

            while (_spaceManager.TryExtendUp(toExtendUp, out toExtendUp))
            {
                _spaceManager.TryAddLevel(dimension);
            }
        }
        bool ISpaceManager.AddPoint <T>(Dimension <T> dimension, SpacePoint <T> sp, float position)
        {
            if (dimension == null || sp == null)
            {
                return(false);
            }

            MustBe.Null(sp.Dimensions[dimension.Index], () => "space point already has assigned the dimension with index=" + dimension.Index);

            if (dimension.HeadDimPoint == null)
            {
                var dp = new DimensionPoint <T>(dimension)
                {
                    Position = position
                };
                dp.HeadLink = dp.TailLink = new DimensionLink <T>(0, dp);
                dp.AddPoint(sp);
                dimension.HeadDimPoint = dimension.TailDimPoint = dp;
                dimension.Count        = 1;
                return(true);
            }

            // try to find existing dimension point
            DimensionPoint <T> left;
            DimensionPoint <T> right;

            if (_spaceManager.TryFindDimensionPoint(dimension, position, out left, out right))
            {
                // if found add the space point to it
                return(left.AddPoint(sp));
            }
            // new head
            if (left == null)
            {
                AppendNewHead(dimension, sp, position);
                dimension.Count++;
                return(true);
            }
            // new tail
            if (right == null)
            {
                AppendNewTail(dimension, sp, position);
                dimension.Count++;
                return(true);
            }

            // new in between
            var newPoint = new DimensionPoint <T>(dimension)
            {
                Position = position
            };

            newPoint.AddPoint(sp);
            var newLink = new DimensionLink <T>(0, newPoint);

            newPoint.HeadLink = newLink;
            newPoint.TailLink = newLink;

            left.HeadLink.AssignNext(newLink);
            newLink.AssignNext(right.HeadLink);

            // for fast movers do not normalize the tree
            if (!sp.IsFastMover)
            {
                _spaceManager.TryAddLevel(dimension);
                var toExtendUp = newLink.GetSiblingExtensionCandidate();
                while (_spaceManager.TryExtendUp(toExtendUp, out toExtendUp))
                {
                    _spaceManager.TryAddLevel(dimension);
                }
            }
            dimension.Count++;
            return(true);
        }
        private bool PopulateDimension <T>(Dimension <T> dimension, List <SpacePointSource <T> > points)
        {
            if (points.Count == 0)
            {
                return(false);
            }

            points.Sort(new SpacePointComparer <T>(dimension.Index));
            //points.Sort((a, b) => a.InitialPositions[dimension.Index].CompareTo(b.InitialPositions[dimension.Index]));

            DimensionPoint <T> head = null;
            DimensionPoint <T> curr = null;
            DimensionPoint <T> prev = null;

            for (var i = 0; i < points.Count; ++i)
            {
                var sp = points[i];
                if (sp == null)
                {
                    continue;
                }
                var position = sp.InitialPositions[dimension.Index];
                if (prev != null)
                {
                    if (dimension.Eq(prev.Position, position))
                    {
                        prev.AddPoint(sp);
                        continue;
                    }
                }
                curr = new DimensionPoint <T>(dimension)
                {
                    Position = position
                };
                curr.HeadLink = new DimensionLink <T>(0, curr);
                curr.TailLink = curr.HeadLink;
                curr.AddPoint(sp);

                if (prev != null)
                {
                    prev.HeadLink.AssignNext(curr.HeadLink);
                }
                else
                {
                    head = curr;
                }
                prev = curr;
            }

            dimension.HeadDimPoint = head;
            dimension.TailDimPoint = curr;
            dimension.Count       += points.Count;

            // ReSharper disable PossibleNullReferenceException
            DimensionLink <T> link = dimension.HeadDimPoint.HeadLink;

            // ReSharper restore PossibleNullReferenceException

            // if this is the top level
            if (link.Next == null || link.Next.Next == null)
            {
                return(true);
            }

            DimensionLink <T> prevUpper  = null;
            DimensionLink <T> firstUpper = null;

            while (link != null)
            {
                var upper = new DimensionLink <T>((byte)(link.Level + 1));
                if (firstUpper == null)
                {
                    firstUpper = upper;
                }
                link.AssignUpper(upper);
                link.DimPoint.TailLink = upper;
                if (prevUpper != null)
                {
                    prevUpper.AssignNext(upper);
                }
                // if this is the end
                if (link.Next == null)
                {
                    link       = firstUpper;
                    firstUpper = null;
                    prevUpper  = null;
                    // if this is the top level
                    if (link.Next == null || link.Next.Next == null)
                    {
                        return(true);
                    }
                    continue;
                }
                link = link.Next.Next;
                // the next is the end and it is two links away
                if (link.Next != null && link.Next.Next == null)
                {
                    link = link.Next;
                }
                prevUpper = upper;
            }
            return(true);
        }