C# Page.SetNodeKey方法代码示例

		public bool Seek(Slice key)
		{
			Lazy<Cursor> lazy;
			NodeHeader* node;
			_currentPage = _tree.FindPageFor(key, out node, out lazy);
			_cursor = lazy.Value;
			_cursor.Pop();

		    if (node != null)
		    {
			    _currentPage.SetNodeKey(node, ref _currentInternalKey);
				_currentKey = _currentInternalKey.ToSlice();
				return this.ValidateCurrentKey(Current, _currentPage);
		    }
		    
            // The key is not found in the db, but we are Seek()ing for equals or starts with.
		    // We know that the exact value isn't there, but it is possible that the next page has values 
		    // that is actually greater than the key, so we need to check it as well.

		    _currentPage.LastSearchPosition = _currentPage.NumberOfEntries; // force next MoveNext to move to the next _page_.
		    return MoveNext();
		}

        private void ExpandMultiTreeNestedPageSize(Transaction tx, Slice key, Slice value, byte* nestedPagePtr, ushort newSize, int currentSize)
        {
            Debug.Assert(newSize > currentSize);
            TemporaryPage tmp;
            using (tx.Environment.GetTemporaryPage(tx, out tmp))
            {
                var tempPagePointer = tmp.TempPagePointer;
                NativeMethods.memcpy(tempPagePointer, nestedPagePtr, currentSize);
                Delete(key); // release our current page
                Page nestedPage = new Page(tempPagePointer, "multi tree", (ushort)currentSize);

                var ptr = DirectAdd(key, newSize);

                var newNestedPage = new Page(ptr, "multi tree", newSize)
                {
                    Lower = (ushort)Constants.PageHeaderSize,
                    Upper = KeysPrefixing ? (ushort) (newSize - Constants.PrefixInfoSectionSize) : newSize,
                    Flags = KeysPrefixing ? PageFlags.Leaf | PageFlags.KeysPrefixed : PageFlags.Leaf,
                    PageNumber = -1L // mark as invalid page number
                };

                newNestedPage.ClearPrefixInfo();

                MemorySlice nodeKey = nestedPage.CreateNewEmptyKey();
                for (int i = 0; i < nestedPage.NumberOfEntries; i++)
                {
                    var nodeHeader = nestedPage.GetNode(i);
                    nestedPage.SetNodeKey(nodeHeader, ref nodeKey);
                    nodeKey = newNestedPage.PrepareKeyToInsert(nodeKey, i);
                    newNestedPage.AddDataNode(i, nodeKey, 0,
                        (ushort)(nodeHeader->Version - 1)); // we dec by one because AdddataNode will inc by one, and we don't want to change those values
                }

                newNestedPage.Search(value);
                newNestedPage.AddDataNode(newNestedPage.LastSearchPosition, newNestedPage.PrepareKeyToInsert(value, newNestedPage.LastSearchPosition), 0, 0);
            }
        }

		public bool MovePrev()
		{
			while (true)
			{
				_currentPage.LastSearchPosition--;
				if (_currentPage.LastSearchPosition >= 0)
				{
					// run out of entries, need to select the next page...
					while (_currentPage.IsBranch)
					{
						_cursor.Push(_currentPage);
						var node = _currentPage.GetNode(_currentPage.LastSearchPosition);
						_currentPage = _tx.GetReadOnlyPage(node->PageNumber);
						_currentPage.LastSearchPosition = _currentPage.NumberOfEntries - 1;
					}
					var current = _currentPage.GetNode(_currentPage.LastSearchPosition);
					if (this.ValidateCurrentKey(current, _currentPage) == false)
						return false;

					_currentPage.SetNodeKey(current, ref _currentInternalKey);
					_currentKey = _currentInternalKey.ToSlice();
					return true;// there is another entry in this page
				}
				if (_cursor.PageCount == 0)
					break;
				_currentPage = _cursor.Pop();
			}
			_currentPage = null;
			return false;
		}