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1163 lines
32 KiB
C++
1163 lines
32 KiB
C++
#ifndef __B_PLUS_TREE_CPP
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#define __B_PLUS_TREE_CPP
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#include "DS_MemoryPool.h"
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#include "DS_Queue.h"
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#include <stdio.h>
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#include "Export.h"
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// Java
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// http://www.seanster.com/BplusTree/BplusTree.html
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// Overview
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// http://babbage.clarku.edu/~achou/cs160/B+Trees/B+Trees.htm
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// Deletion
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// http://dbpubs.stanford.edu:8090/pub/1995-19
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#ifdef _MSC_VER
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#pragma warning( push )
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#endif
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#include "RakMemoryOverride.h"
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/// The namespace DataStructures was only added to avoid compiler errors for commonly named data structures
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/// As these data structures are stand-alone, you can use them outside of RakNet for your own projects if you wish.
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namespace DataStructures
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{
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/// Used in the BPlusTree. Used for both leaf and index nodes.
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/// Don't use a constructor or destructor, due to the memory pool I am using
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template <class KeyType, class DataType, int order>
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struct RAK_DLL_EXPORT Page : public RakNet::RakMemoryOverride
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{
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// We use the same data structure for both leaf and index nodes. It uses a little more memory for index nodes but reduces
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// memory fragmentation, allocations, and deallocations.
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bool isLeaf;
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// Used for both leaf and index nodes.
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// For a leaf it means the number of elements in data
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// For an index it means the number of keys and is one less than the number of children pointers.
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int size;
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// Used for both leaf and index nodes.
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KeyType keys[order];
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// Used only for leaf nodes. Data is the actual data, while next is the pointer to the next leaf (for B+)
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DataType data[order];
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Page<KeyType, DataType, order> *next;
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Page<KeyType, DataType, order> *previous;
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// Used only for index nodes. Pointers to the children of this node.
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Page *children[order+1];
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};
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/// A BPlus tree
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/// Written with efficiency and speed in mind.
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template <class KeyType, class DataType, int order>
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class RAK_DLL_EXPORT BPlusTree : public RakNet::RakMemoryOverride
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{
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public:
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struct ReturnAction
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{
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KeyType key1;
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KeyType key2;
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enum
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{
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NO_ACTION,
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REPLACE_KEY1_WITH_KEY2,
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PUSH_KEY_TO_PARENT,
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SET_BRANCH_KEY,
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} action; // 0=none, 1=replace key1 with key2
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};
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BPlusTree();
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~BPlusTree();
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void SetPoolPageSize(int size); // Set the page size for the memory pool. Optionsl
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bool Get(const KeyType key, DataType &out) const;
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bool Delete(const KeyType key);
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bool Delete(const KeyType key, DataType &out);
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bool Insert(const KeyType key, const DataType &data);
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void Clear(void);
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unsigned Size(void) const;
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bool IsEmpty(void) const;
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Page<KeyType, DataType, order> *GetListHead(void) const;
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DataType GetDataHead(void) const;
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void PrintLeaves(void);
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void ForEachLeaf(void (*func)(Page<KeyType, DataType, order> * leaf, int index));
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void ForEachData(void (*func)(DataType input, int index));
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void PrintGraph(void);
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void ValidateTree(void);
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protected:
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void ValidateTreeRecursive(Page<KeyType, DataType, order> *cur);
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void DeleteFromPageAtIndex(const int index, Page<KeyType, DataType, order> *cur);
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static void PrintLeaf(Page<KeyType, DataType, order> * leaf, int index);
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void FreePages(void);
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bool GetIndexOf(const KeyType key, Page<KeyType, DataType, order> *page, int *out) const;
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void ShiftKeysLeft(Page<KeyType, DataType, order> *cur);
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bool CanRotateLeft(Page<KeyType, DataType, order> *cur, int childIndex);
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bool CanRotateRight(Page<KeyType, DataType, order> *cur, int childIndex);
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void RotateRight(Page<KeyType, DataType, order> *cur, int childIndex, ReturnAction *returnAction);
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void RotateLeft(Page<KeyType, DataType, order> *cur, int childIndex, ReturnAction *returnAction);
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Page<KeyType, DataType, order>* InsertIntoNode(const KeyType key, const DataType &childData, int insertionIndex, Page<KeyType, DataType, order> *nodeData, Page<KeyType, DataType, order> *cur, ReturnAction* returnAction);
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Page<KeyType, DataType, order>* InsertBranchDown(const KeyType key, const DataType &data,Page<KeyType, DataType, order> *cur, ReturnAction* returnAction, bool *success);
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Page<KeyType, DataType, order>* GetLeafFromKey(const KeyType key) const;
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bool FindDeleteRebalance(const KeyType key, Page<KeyType, DataType, order> *cur, bool *underflow, KeyType rightRootKey, ReturnAction *returnAction, DataType &out);
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bool FixUnderflow(int branchIndex, Page<KeyType, DataType, order> *cur, KeyType rightRootKey, ReturnAction *returnAction);
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void ShiftNodeLeft(Page<KeyType, DataType, order> *cur);
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void ShiftNodeRight(Page<KeyType, DataType, order> *cur);
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MemoryPool<Page<KeyType, DataType, order> > pagePool;
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Page<KeyType, DataType, order> *root, *leftmostLeaf;
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};
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template<class KeyType, class DataType, int order>
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BPlusTree<KeyType, DataType, order>::BPlusTree ()
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{
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assert(order>1);
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root=0;
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leftmostLeaf=0;
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}
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template<class KeyType, class DataType, int order>
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BPlusTree<KeyType, DataType, order>::~BPlusTree ()
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{
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Clear();
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}
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template<class KeyType, class DataType, int order>
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void BPlusTree<KeyType, DataType, order>::SetPoolPageSize(int size)
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{
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pagePool.SetPageSize(size);
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}
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template<class KeyType, class DataType, int order>
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bool BPlusTree<KeyType, DataType, order>::Get(const KeyType key, DataType &out) const
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{
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if (root==0)
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return false;
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Page<KeyType, DataType, order>* leaf = GetLeafFromKey(key);
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int childIndex;
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if (GetIndexOf(key, leaf, &childIndex))
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{
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out=leaf->data[childIndex];
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return true;
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}
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return false;
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}
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template<class KeyType, class DataType, int order>
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void BPlusTree<KeyType, DataType, order>::DeleteFromPageAtIndex(const int index, Page<KeyType, DataType, order> *cur)
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{
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int i;
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for (i=index; i < cur->size-1; i++)
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cur->keys[i]=cur->keys[i+1];
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if (cur->isLeaf)
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{
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for (i=index; i < cur->size-1; i++)
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cur->data[i]=cur->data[i+1];
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}
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else
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{
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for (i=index; i < cur->size-1; i++)
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cur->children[i+1]=cur->children[i+2];
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}
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cur->size--;
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}
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template<class KeyType, class DataType, int order>
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bool BPlusTree<KeyType, DataType, order>::Delete(const KeyType key)
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{
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DataType temp;
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return Delete(key, temp);
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}
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template<class KeyType, class DataType, int order>
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bool BPlusTree<KeyType, DataType, order>::Delete(const KeyType key, DataType &out)
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{
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if (root==0)
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return false;
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ReturnAction returnAction;
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returnAction.action=ReturnAction::NO_ACTION;
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int childIndex;
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bool underflow=false;
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if (root==leftmostLeaf)
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{
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if (GetIndexOf(key, root, &childIndex)==false)
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return false;
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out=root->data[childIndex];
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DeleteFromPageAtIndex(childIndex,root);
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if (root->size==0)
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{
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pagePool.Release(root);
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root=0;
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leftmostLeaf=0;
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}
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return true;
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}
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else if (FindDeleteRebalance(key, root, &underflow,root->keys[0], &returnAction, out)==false)
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return false;
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// assert(returnAction.action==ReturnAction::NO_ACTION);
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if (underflow && root->size==0)
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{
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// Move the root down.
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Page<KeyType, DataType, order> *oldRoot=root;
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root=root->children[0];
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pagePool.Release(oldRoot);
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// memset(oldRoot,0,sizeof(root));
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}
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return true;
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}
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template<class KeyType, class DataType, int order>
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bool BPlusTree<KeyType, DataType, order>::FindDeleteRebalance(const KeyType key, Page<KeyType, DataType, order> *cur, bool *underflow, KeyType rightRootKey, ReturnAction *returnAction, DataType &out)
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{
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// Get index of child to follow.
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int branchIndex, childIndex;
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if (GetIndexOf(key, cur, &childIndex))
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branchIndex=childIndex+1;
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else
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branchIndex=childIndex;
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// If child is not a leaf, call recursively
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if (cur->children[branchIndex]->isLeaf==false)
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{
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if (branchIndex<cur->size)
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rightRootKey=cur->keys[branchIndex]; // Shift right to left
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else
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rightRootKey=cur->keys[branchIndex-1]; // Shift center to left
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if (FindDeleteRebalance(key, cur->children[branchIndex], underflow, rightRootKey, returnAction, out)==false)
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return false;
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// Call again in case the root key changed
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if (branchIndex<cur->size)
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rightRootKey=cur->keys[branchIndex]; // Shift right to left
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else
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rightRootKey=cur->keys[branchIndex-1]; // Shift center to left
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if (returnAction->action==ReturnAction::SET_BRANCH_KEY && branchIndex!=childIndex)
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{
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returnAction->action=ReturnAction::NO_ACTION;
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cur->keys[childIndex]=returnAction->key1;
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if (branchIndex<cur->size)
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rightRootKey=cur->keys[branchIndex]; // Shift right to left
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else
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rightRootKey=cur->keys[branchIndex-1]; // Shift center to left
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}
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}
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else
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{
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// If child is a leaf, get the index of the key. If the item is not found, cancel delete.
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if (GetIndexOf(key, cur->children[branchIndex], &childIndex)==false)
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return false;
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// Delete:
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// Remove childIndex from the child at branchIndex
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out=cur->children[branchIndex]->data[childIndex];
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DeleteFromPageAtIndex(childIndex, cur->children[branchIndex]);
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if (childIndex==0)
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{
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if (branchIndex>0)
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cur->keys[branchIndex-1]=cur->children[branchIndex]->keys[0];
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if (branchIndex==0)
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{
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returnAction->action=ReturnAction::SET_BRANCH_KEY;
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returnAction->key1=cur->children[0]->keys[0];
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}
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}
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if (cur->children[branchIndex]->size < order/2)
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*underflow=true;
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else
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*underflow=false;
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}
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// Fix underflow:
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if (*underflow)
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{
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*underflow=FixUnderflow(branchIndex, cur, rightRootKey, returnAction);
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}
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return true;
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}
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template<class KeyType, class DataType, int order>
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bool BPlusTree<KeyType, DataType, order>::FixUnderflow(int branchIndex, Page<KeyType, DataType, order> *cur, KeyType rightRootKey, ReturnAction *returnAction)
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{
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// Borrow from a neighbor that has excess.
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Page<KeyType, DataType, order> *source;
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Page<KeyType, DataType, order> *dest;
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if (branchIndex>0 && cur->children[branchIndex-1]->size > order/2)
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{
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dest=cur->children[branchIndex];
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source=cur->children[branchIndex-1];
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// Left has excess
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ShiftNodeRight(dest);
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if (dest->isLeaf)
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{
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dest->keys[0]=source->keys[source->size-1];
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dest->data[0]=source->data[source->size-1];
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}
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else
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{
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dest->children[0]=source->children[source->size];
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dest->keys[0]=cur->keys[branchIndex-1];
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}
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// Update the parent key for the child (middle)
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cur->keys[branchIndex-1]=source->keys[source->size-1];
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source->size--;
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// if (branchIndex==0)
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// {
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// returnAction->action=ReturnAction::SET_BRANCH_KEY;
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// returnAction->key1=dest->keys[0];
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// }
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// No underflow
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return false;
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}
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else if (branchIndex<cur->size && cur->children[branchIndex+1]->size > order/2)
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{
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dest=cur->children[branchIndex];
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source=cur->children[branchIndex+1];
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// Right has excess
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if (dest->isLeaf)
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{
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dest->keys[dest->size]=source->keys[0];
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dest->data[dest->size]=source->data[0];
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// The first key in the leaf after shifting is the parent key for the right branch
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cur->keys[branchIndex]=source->keys[1];
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#ifdef _MSC_VER
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#pragma warning( disable : 4127 ) // warning C4127: conditional expression is constant
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#endif
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if (order<=3 && dest->size==0)
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{
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if (branchIndex==0)
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{
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returnAction->action=ReturnAction::SET_BRANCH_KEY;
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returnAction->key1=dest->keys[0];
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}
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else
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cur->keys[branchIndex-1]=cur->children[branchIndex]->keys[0];
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}
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}
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else
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{
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if (returnAction->action==ReturnAction::NO_ACTION)
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{
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returnAction->action=ReturnAction::SET_BRANCH_KEY;
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returnAction->key1=dest->keys[0];
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}
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dest->keys[dest->size]=rightRootKey;
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dest->children[dest->size+1]=source->children[0];
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// The shifted off key is the leftmost key for a node
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cur->keys[branchIndex]=source->keys[0];
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}
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dest->size++;
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ShiftNodeLeft(source);
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//cur->keys[branchIndex]=source->keys[0];
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// returnAction->action=ReturnAction::SET_BRANCH_KEY;
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// returnAction->key1=dest->keys[dest->size-1];
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// No underflow
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return false;
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}
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else
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{
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int sourceIndex;
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// If no neighbors have excess, merge two branches.
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//
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// To merge two leaves, just copy the data and keys over.
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//
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// To merge two branches, copy the pointers and keys over, using rightRootKey as the key for the extra pointer
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if (branchIndex<cur->size)
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{
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// Merge right child to current child and delete right child.
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dest=cur->children[branchIndex];
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source=cur->children[branchIndex+1];
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}
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else
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{
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// Move current child to left and delete current child
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dest=cur->children[branchIndex-1];
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source=cur->children[branchIndex];
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}
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// Merge
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if (dest->isLeaf)
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{
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for (sourceIndex=0; sourceIndex<source->size; sourceIndex++)
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{
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dest->keys[dest->size]=source->keys[sourceIndex];
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dest->data[dest->size++]=source->data[sourceIndex];
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}
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}
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else
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{
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// We want the tree root key of the source, not the current.
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dest->keys[dest->size]=rightRootKey;
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dest->children[dest->size++ + 1]=source->children[0];
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for (sourceIndex=0; sourceIndex<source->size; sourceIndex++)
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{
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dest->keys[dest->size]=source->keys[sourceIndex];
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dest->children[dest->size++ + 1]=source->children[sourceIndex + 1];
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}
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}
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#ifdef _MSC_VER
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#pragma warning( disable : 4127 ) // warning C4127: conditional expression is constant
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#endif
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if (order<=3 && branchIndex>0 && cur->children[branchIndex]->isLeaf) // With order==2 it is possible to delete data[0], which is not possible with higher orders.
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cur->keys[branchIndex-1]=cur->children[branchIndex]->keys[0];
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if (branchIndex<cur->size)
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{
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// Update the parent key, removing the source (right)
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DeleteFromPageAtIndex(branchIndex, cur);
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}
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else
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{
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if (branchIndex>0)
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{
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// Update parent key, removing the source (current)
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DeleteFromPageAtIndex(branchIndex-1, cur);
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}
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}
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if (branchIndex==0 && dest->isLeaf)
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{
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returnAction->action=ReturnAction::SET_BRANCH_KEY;
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returnAction->key1=dest->keys[0];
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}
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if (source==leftmostLeaf)
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leftmostLeaf=source->next;
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if (source->isLeaf)
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{
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if (source->previous)
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source->previous->next=source->next;
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if (source->next)
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source->next->previous=source->previous;
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}
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// Free the source node
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pagePool.Release(source);
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// memset(source,0,sizeof(root));
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// Return underflow or not of parent.
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return cur->size < order/2;
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}
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}
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template<class KeyType, class DataType, int order>
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void BPlusTree<KeyType, DataType, order>::ShiftNodeRight(Page<KeyType, DataType, order> *cur)
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{
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int i;
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for (i=cur->size; i>0; i--)
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cur->keys[i]=cur->keys[i-1];
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if (cur->isLeaf)
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{
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for (i=cur->size; i>0; i--)
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cur->data[i]=cur->data[i-1];
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}
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else
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{
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for (i=cur->size+1; i>0; i--)
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cur->children[i]=cur->children[i-1];
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}
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cur->size++;
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}
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template<class KeyType, class DataType, int order>
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void BPlusTree<KeyType, DataType, order>::ShiftNodeLeft(Page<KeyType, DataType, order> *cur)
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{
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int i;
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for (i=0; i < cur->size-1; i++)
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cur->keys[i]=cur->keys[i+1];
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if (cur->isLeaf)
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{
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for (i=0; i < cur->size; i++)
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cur->data[i]=cur->data[i+1];
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}
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else
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{
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for (i=0; i < cur->size; i++)
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cur->children[i]=cur->children[i+1];
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}
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cur->size--;
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}
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template<class KeyType, class DataType, int order>
|
|
Page<KeyType, DataType, order>* BPlusTree<KeyType, DataType, order>::InsertIntoNode(const KeyType key, const DataType &leafData, int insertionIndex, Page<KeyType, DataType, order> *nodeData, Page<KeyType, DataType, order> *cur, ReturnAction* returnAction)
|
|
{
|
|
int i;
|
|
if (cur->size < order)
|
|
{
|
|
for (i=cur->size; i > insertionIndex; i--)
|
|
cur->keys[i]=cur->keys[i-1];
|
|
if (cur->isLeaf)
|
|
{
|
|
for (i=cur->size; i > insertionIndex; i--)
|
|
cur->data[i]=cur->data[i-1];
|
|
}
|
|
else
|
|
{
|
|
for (i=cur->size+1; i > insertionIndex+1; i--)
|
|
cur->children[i]=cur->children[i-1];
|
|
}
|
|
cur->keys[insertionIndex]=key;
|
|
if (cur->isLeaf)
|
|
cur->data[insertionIndex]=leafData;
|
|
else
|
|
cur->children[insertionIndex+1]=nodeData;
|
|
|
|
cur->size++;
|
|
}
|
|
else
|
|
{
|
|
Page<KeyType, DataType, order>* newPage = pagePool.Allocate();
|
|
newPage->isLeaf=cur->isLeaf;
|
|
if (cur->isLeaf)
|
|
{
|
|
newPage->next=cur->next;
|
|
if (cur->next)
|
|
cur->next->previous=newPage;
|
|
newPage->previous=cur;
|
|
cur->next=newPage;
|
|
}
|
|
|
|
int destIndex, sourceIndex;
|
|
|
|
if (insertionIndex>=(order+1)/2)
|
|
{
|
|
destIndex=0;
|
|
sourceIndex=order/2;
|
|
|
|
for (; sourceIndex < insertionIndex; sourceIndex++, destIndex++)
|
|
{
|
|
newPage->keys[destIndex]=cur->keys[sourceIndex];
|
|
}
|
|
newPage->keys[destIndex++]=key;
|
|
for (; sourceIndex < order; sourceIndex++, destIndex++)
|
|
{
|
|
newPage->keys[destIndex]=cur->keys[sourceIndex];
|
|
}
|
|
|
|
destIndex=0;
|
|
sourceIndex=order/2;
|
|
if (cur->isLeaf)
|
|
{
|
|
for (; sourceIndex < insertionIndex; sourceIndex++, destIndex++)
|
|
{
|
|
newPage->data[destIndex]=cur->data[sourceIndex];
|
|
}
|
|
newPage->data[destIndex++]=leafData;
|
|
for (; sourceIndex < order; sourceIndex++, destIndex++)
|
|
{
|
|
newPage->data[destIndex]=cur->data[sourceIndex];
|
|
}
|
|
}
|
|
else
|
|
{
|
|
|
|
for (; sourceIndex < insertionIndex; sourceIndex++, destIndex++)
|
|
{
|
|
newPage->children[destIndex]=cur->children[sourceIndex+1];
|
|
}
|
|
newPage->children[destIndex++]=nodeData;
|
|
|
|
// sourceIndex+1 is sort of a hack but it works - because there is one extra child than keys
|
|
// skip past the last child for cur
|
|
for (; sourceIndex+1 < cur->size+1; sourceIndex++, destIndex++)
|
|
{
|
|
newPage->children[destIndex]=cur->children[sourceIndex+1];
|
|
}
|
|
|
|
// the first key is the middle key. Remove it from the page and push it to the parent
|
|
returnAction->action=ReturnAction::PUSH_KEY_TO_PARENT;
|
|
returnAction->key1=newPage->keys[0];
|
|
for (int i=0; i < destIndex-1; i++)
|
|
newPage->keys[i]=newPage->keys[i+1];
|
|
|
|
}
|
|
cur->size=order/2;
|
|
}
|
|
else
|
|
{
|
|
destIndex=0;
|
|
sourceIndex=(order+1)/2-1;
|
|
for (; sourceIndex < order; sourceIndex++, destIndex++)
|
|
newPage->keys[destIndex]=cur->keys[sourceIndex];
|
|
destIndex=0;
|
|
if (cur->isLeaf)
|
|
{
|
|
sourceIndex=(order+1)/2-1;
|
|
for (; sourceIndex < order; sourceIndex++, destIndex++)
|
|
newPage->data[destIndex]=cur->data[sourceIndex];
|
|
}
|
|
else
|
|
{
|
|
sourceIndex=(order+1)/2;
|
|
for (; sourceIndex < order+1; sourceIndex++, destIndex++)
|
|
newPage->children[destIndex]=cur->children[sourceIndex];
|
|
|
|
// the first key is the middle key. Remove it from the page and push it to the parent
|
|
returnAction->action=ReturnAction::PUSH_KEY_TO_PARENT;
|
|
returnAction->key1=newPage->keys[0];
|
|
for (int i=0; i < destIndex-1; i++)
|
|
newPage->keys[i]=newPage->keys[i+1];
|
|
}
|
|
cur->size=(order+1)/2-1;
|
|
if (cur->size)
|
|
{
|
|
bool b = GetIndexOf(key, cur, &insertionIndex);
|
|
(void) b;
|
|
assert(b==false);
|
|
}
|
|
else
|
|
insertionIndex=0;
|
|
InsertIntoNode(key, leafData, insertionIndex, nodeData, cur, returnAction);
|
|
}
|
|
|
|
newPage->size=destIndex;
|
|
|
|
return newPage;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
template<class KeyType, class DataType, int order>
|
|
bool BPlusTree<KeyType, DataType, order>::CanRotateLeft(Page<KeyType, DataType, order> *cur, int childIndex)
|
|
{
|
|
return childIndex>0 && cur->children[childIndex-1]->size<order;
|
|
}
|
|
|
|
template<class KeyType, class DataType, int order>
|
|
void BPlusTree<KeyType, DataType, order>::RotateLeft(Page<KeyType, DataType, order> *cur, int childIndex, ReturnAction *returnAction)
|
|
{
|
|
Page<KeyType, DataType, order> *dest = cur->children[childIndex-1];
|
|
Page<KeyType, DataType, order> *source = cur->children[childIndex];
|
|
returnAction->key1=source->keys[0];
|
|
dest->keys[dest->size]=source->keys[0];
|
|
dest->data[dest->size]=source->data[0];
|
|
dest->size++;
|
|
for (int i=0; i < source->size-1; i++)
|
|
{
|
|
source->keys[i]=source->keys[i+1];
|
|
source->data[i]=source->data[i+1];
|
|
}
|
|
source->size--;
|
|
cur->keys[childIndex-1]=source->keys[0];
|
|
returnAction->key2=source->keys[0];
|
|
}
|
|
|
|
template<class KeyType, class DataType, int order>
|
|
bool BPlusTree<KeyType, DataType, order>::CanRotateRight(Page<KeyType, DataType, order> *cur, int childIndex)
|
|
{
|
|
return childIndex < cur->size && cur->children[childIndex+1]->size<order;
|
|
}
|
|
|
|
template<class KeyType, class DataType, int order>
|
|
void BPlusTree<KeyType, DataType, order>::RotateRight(Page<KeyType, DataType, order> *cur, int childIndex, ReturnAction *returnAction)
|
|
{
|
|
Page<KeyType, DataType, order> *dest = cur->children[childIndex+1];
|
|
Page<KeyType, DataType, order> *source = cur->children[childIndex];
|
|
returnAction->key1=dest->keys[0];
|
|
for (int i= dest->size; i > 0; i--)
|
|
{
|
|
dest->keys[i]=dest->keys[i-1];
|
|
dest->data[i]=dest->data[i-1];
|
|
}
|
|
dest->keys[0]=source->keys[source->size-1];
|
|
dest->data[0]=source->data[source->size-1];
|
|
dest->size++;
|
|
source->size--;
|
|
|
|
cur->keys[childIndex]=dest->keys[0];
|
|
returnAction->key2=dest->keys[0];
|
|
}
|
|
template<class KeyType, class DataType, int order>
|
|
Page<KeyType, DataType, order>* BPlusTree<KeyType, DataType, order>::GetLeafFromKey(const KeyType key) const
|
|
{
|
|
Page<KeyType, DataType, order>* cur = root;
|
|
int childIndex;
|
|
while (cur->isLeaf==false)
|
|
{
|
|
// When searching, if we match the exact key we go down the pointer after that index
|
|
if (GetIndexOf(key, cur, &childIndex))
|
|
childIndex++;
|
|
cur = cur->children[childIndex];
|
|
}
|
|
return cur;
|
|
}
|
|
|
|
template<class KeyType, class DataType, int order>
|
|
Page<KeyType, DataType, order>* BPlusTree<KeyType, DataType, order>::InsertBranchDown(const KeyType key, const DataType &data,Page<KeyType, DataType, order> *cur, ReturnAction *returnAction, bool *success)
|
|
{
|
|
int childIndex;
|
|
int branchIndex;
|
|
if (GetIndexOf(key, cur, &childIndex))
|
|
branchIndex=childIndex+1;
|
|
else
|
|
branchIndex=childIndex;
|
|
Page<KeyType, DataType, order>* newPage;
|
|
if (cur->isLeaf==false)
|
|
{
|
|
if (cur->children[branchIndex]->isLeaf==true && cur->children[branchIndex]->size==order)
|
|
{
|
|
if (branchIndex==childIndex+1)
|
|
{
|
|
*success=false;
|
|
return 0; // Already exists
|
|
}
|
|
|
|
if (CanRotateLeft(cur, branchIndex))
|
|
{
|
|
returnAction->action=ReturnAction::REPLACE_KEY1_WITH_KEY2;
|
|
if (key > cur->children[branchIndex]->keys[0])
|
|
{
|
|
RotateLeft(cur, branchIndex, returnAction);
|
|
|
|
int insertionIndex;
|
|
GetIndexOf(key, cur->children[branchIndex], &insertionIndex);
|
|
InsertIntoNode(key, data, insertionIndex, 0, cur->children[branchIndex], 0);
|
|
}
|
|
else
|
|
{
|
|
// Move head element to left and replace it with key,data
|
|
Page<KeyType, DataType, order>* dest=cur->children[branchIndex-1];
|
|
Page<KeyType, DataType, order>* source=cur->children[branchIndex];
|
|
returnAction->key1=source->keys[0];
|
|
returnAction->key2=key;
|
|
dest->keys[dest->size]=source->keys[0];
|
|
dest->data[dest->size]=source->data[0];
|
|
dest->size++;
|
|
source->keys[0]=key;
|
|
source->data[0]=data;
|
|
}
|
|
cur->keys[branchIndex-1]=cur->children[branchIndex]->keys[0];
|
|
|
|
return 0;
|
|
}
|
|
else if (CanRotateRight(cur, branchIndex))
|
|
{
|
|
returnAction->action=ReturnAction::REPLACE_KEY1_WITH_KEY2;
|
|
|
|
if (key < cur->children[branchIndex]->keys[cur->children[branchIndex]->size-1])
|
|
{
|
|
RotateRight(cur, branchIndex, returnAction);
|
|
|
|
int insertionIndex;
|
|
GetIndexOf(key, cur->children[branchIndex], &insertionIndex);
|
|
InsertIntoNode(key, data, insertionIndex, 0, cur->children[branchIndex], 0);
|
|
|
|
}
|
|
else
|
|
{
|
|
// Insert to the head of the right leaf instead and change our key
|
|
returnAction->key1=cur->children[branchIndex+1]->keys[0];
|
|
InsertIntoNode(key, data, 0, 0, cur->children[branchIndex+1], 0);
|
|
returnAction->key2=key;
|
|
}
|
|
cur->keys[branchIndex]=cur->children[branchIndex+1]->keys[0];
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
newPage=InsertBranchDown(key,data,cur->children[branchIndex], returnAction, success);
|
|
if (returnAction->action==ReturnAction::REPLACE_KEY1_WITH_KEY2)
|
|
{
|
|
if (branchIndex>0 && cur->keys[branchIndex-1]==returnAction->key1)
|
|
cur->keys[branchIndex-1]=returnAction->key2;
|
|
}
|
|
if (newPage)
|
|
{
|
|
if (newPage->isLeaf==false)
|
|
{
|
|
assert(returnAction->action==ReturnAction::PUSH_KEY_TO_PARENT);
|
|
newPage->size--;
|
|
return InsertIntoNode(returnAction->key1, data, branchIndex, newPage, cur, returnAction);
|
|
}
|
|
else
|
|
{
|
|
return InsertIntoNode(newPage->keys[0], data, branchIndex, newPage, cur, returnAction);
|
|
}
|
|
}
|
|
}
|
|
else
|
|
{
|
|
if (branchIndex==childIndex+1)
|
|
{
|
|
*success=false;
|
|
return 0; // Already exists
|
|
}
|
|
else
|
|
{
|
|
return InsertIntoNode(key, data, branchIndex, 0, cur, returnAction);
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
template<class KeyType, class DataType, int order>
|
|
bool BPlusTree<KeyType, DataType, order>::Insert(const KeyType key, const DataType &data)
|
|
{
|
|
if (root==0)
|
|
{
|
|
// Allocate root and make root a leaf
|
|
root = pagePool.Allocate();
|
|
root->isLeaf=true;
|
|
leftmostLeaf=root;
|
|
root->size=1;
|
|
root->keys[0]=key;
|
|
root->data[0]=data;
|
|
root->next=0;
|
|
root->previous=0;
|
|
}
|
|
else
|
|
{
|
|
bool success=true;
|
|
ReturnAction returnAction;
|
|
returnAction.action=ReturnAction::NO_ACTION;
|
|
Page<KeyType, DataType, order>* newPage = InsertBranchDown(key, data, root, &returnAction, &success);
|
|
if (success==false)
|
|
return false;
|
|
if (newPage)
|
|
{
|
|
KeyType newKey;
|
|
if (newPage->isLeaf==false)
|
|
{
|
|
// One key is pushed up through the stack. I store that at keys[0] but it has to be removed for the page to be correct
|
|
assert(returnAction.action==ReturnAction::PUSH_KEY_TO_PARENT);
|
|
newKey=returnAction.key1;
|
|
newPage->size--;
|
|
}
|
|
else
|
|
newKey = newPage->keys[0];
|
|
// propagate the root
|
|
Page<KeyType, DataType, order>* newRoot = pagePool.Allocate();
|
|
newRoot->isLeaf=false;
|
|
newRoot->size=1;
|
|
newRoot->keys[0]=newKey;
|
|
newRoot->children[0]=root;
|
|
newRoot->children[1]=newPage;
|
|
root=newRoot;
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
template<class KeyType, class DataType, int order>
|
|
void BPlusTree<KeyType, DataType, order>::ShiftKeysLeft(Page<KeyType, DataType, order> *cur)
|
|
{
|
|
int i;
|
|
for (i=0; i < cur->size; i++)
|
|
cur->keys[i]=cur->keys[i+1];
|
|
}
|
|
template<class KeyType, class DataType, int order>
|
|
void BPlusTree<KeyType, DataType, order>::Clear(void)
|
|
{
|
|
if (root)
|
|
{
|
|
FreePages();
|
|
leftmostLeaf=0;
|
|
root=0;
|
|
}
|
|
pagePool.Clear();
|
|
}
|
|
template<class KeyType, class DataType, int order>
|
|
unsigned BPlusTree<KeyType, DataType, order>::Size(void) const
|
|
{
|
|
int count=0;
|
|
DataStructures::Page<KeyType, DataType, order> *cur = GetListHead();
|
|
while (cur)
|
|
{
|
|
count+=cur->size;
|
|
cur=cur->next;
|
|
}
|
|
return count;
|
|
}
|
|
template<class KeyType, class DataType, int order>
|
|
bool BPlusTree<KeyType, DataType, order>::IsEmpty(void) const
|
|
{
|
|
return root==0;
|
|
}
|
|
template<class KeyType, class DataType, int order>
|
|
bool BPlusTree<KeyType, DataType, order>::GetIndexOf(const KeyType key, Page<KeyType, DataType, order> *page, int *out) const
|
|
{
|
|
assert(page->size>0);
|
|
int index, upperBound, lowerBound;
|
|
upperBound=page->size-1;
|
|
lowerBound=0;
|
|
index = page->size/2;
|
|
|
|
#ifdef _MSC_VER
|
|
#pragma warning( disable : 4127 ) // warning C4127: conditional expression is constant
|
|
#endif
|
|
while (1)
|
|
{
|
|
if (key==page->keys[index])
|
|
{
|
|
*out=index;
|
|
return true;
|
|
}
|
|
else if (key<page->keys[index])
|
|
upperBound=index-1;
|
|
else
|
|
lowerBound=index+1;
|
|
|
|
index=lowerBound+(upperBound-lowerBound)/2;
|
|
|
|
if (lowerBound>upperBound)
|
|
{
|
|
*out=lowerBound;
|
|
return false; // No match
|
|
}
|
|
}
|
|
}
|
|
template<class KeyType, class DataType, int order>
|
|
void BPlusTree<KeyType, DataType, order>::FreePages(void)
|
|
{
|
|
DataStructures::Queue<DataStructures::Page<KeyType, DataType, order> *> queue;
|
|
DataStructures::Page<KeyType, DataType, order> *ptr;
|
|
int i;
|
|
queue.Push(root);
|
|
while (queue.Size())
|
|
{
|
|
ptr=queue.Pop();
|
|
if (ptr->isLeaf==false)
|
|
{
|
|
for (i=0; i < ptr->size+1; i++)
|
|
queue.Push(ptr->children[i]);
|
|
}
|
|
pagePool.Release(ptr);
|
|
// memset(ptr,0,sizeof(root));
|
|
};
|
|
}
|
|
template<class KeyType, class DataType, int order>
|
|
Page<KeyType, DataType, order> *BPlusTree<KeyType, DataType, order>::GetListHead(void) const
|
|
{
|
|
return leftmostLeaf;
|
|
}
|
|
template<class KeyType, class DataType, int order>
|
|
DataType BPlusTree<KeyType, DataType, order>::GetDataHead(void) const
|
|
{
|
|
return leftmostLeaf->data[0];
|
|
}
|
|
template<class KeyType, class DataType, int order>
|
|
void BPlusTree<KeyType, DataType, order>::ForEachLeaf(void (*func)(Page<KeyType, DataType, order> * leaf, int index))
|
|
{
|
|
int count=0;
|
|
DataStructures::Page<KeyType, DataType, order> *cur = GetListHead();
|
|
while (cur)
|
|
{
|
|
func(cur, count++);
|
|
cur=cur->next;
|
|
}
|
|
}
|
|
template<class KeyType, class DataType, int order>
|
|
void BPlusTree<KeyType, DataType, order>::ForEachData(void (*func)(DataType input, int index))
|
|
{
|
|
int count=0,i;
|
|
DataStructures::Page<KeyType, DataType, order> *cur = GetListHead();
|
|
while (cur)
|
|
{
|
|
for (i=0; i < cur->size; i++)
|
|
func(cur->data[i], count++);
|
|
cur=cur->next;
|
|
}
|
|
}
|
|
template<class KeyType, class DataType, int order>
|
|
void BPlusTree<KeyType, DataType, order>::PrintLeaf(Page<KeyType, DataType, order> * leaf, int index)
|
|
{
|
|
int i;
|
|
printf("%i] SELF=%p\n", index+1, leaf);
|
|
for (i=0; i < leaf->size; i++)
|
|
printf(" %i. %i\n", i+1, leaf->data[i]);
|
|
}
|
|
template<class KeyType, class DataType, int order>
|
|
void BPlusTree<KeyType, DataType, order>::PrintLeaves(void)
|
|
{
|
|
ForEachLeaf(PrintLeaf);
|
|
}
|
|
|
|
template<class KeyType, class DataType, int order>
|
|
void BPlusTree<KeyType, DataType, order>::ValidateTree(void)
|
|
{
|
|
int i, last=-9999;
|
|
DataStructures::Page<KeyType, DataType, order> *cur = GetListHead();
|
|
while (cur)
|
|
{
|
|
assert(cur->size>0);
|
|
for (i=0; i < cur->size; i++)
|
|
{
|
|
assert(cur->data[i]==cur->keys[i]);
|
|
if (last!=-9999)
|
|
{
|
|
assert(cur->data[i]>last);
|
|
}
|
|
last=cur->data[i];
|
|
}
|
|
cur=cur->next;
|
|
}
|
|
if (root && root->isLeaf==false)
|
|
ValidateTreeRecursive(root);
|
|
}
|
|
template<class KeyType, class DataType, int order>
|
|
void BPlusTree<KeyType, DataType, order>::ValidateTreeRecursive(Page<KeyType, DataType, order> *cur)
|
|
{
|
|
assert(cur==root || cur->size>=order/2);
|
|
|
|
if (cur->children[0]->isLeaf)
|
|
{
|
|
assert(cur->children[0]->keys[0] < cur->keys[0]);
|
|
for (int i=0; i < cur->size; i++)
|
|
{
|
|
assert(cur->children[i+1]->keys[0]==cur->keys[i]);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
for (int i=0; i < cur->size+1; i++)
|
|
ValidateTreeRecursive(cur->children[i]);
|
|
}
|
|
}
|
|
|
|
template<class KeyType, class DataType, int order>
|
|
void BPlusTree<KeyType, DataType, order>::PrintGraph(void)
|
|
{
|
|
DataStructures::Queue<DataStructures::Page<KeyType, DataType, order> *> queue;
|
|
queue.Push(root);
|
|
queue.Push(0);
|
|
DataStructures::Page<KeyType, DataType, order> *ptr;
|
|
int i,j;
|
|
if (root)
|
|
{
|
|
printf("%p(", root);
|
|
for (i=0; i < root->size; i++)
|
|
{
|
|
printf("%i ", root->keys[i]);
|
|
}
|
|
printf(") ");
|
|
printf("\n");
|
|
}
|
|
while (queue.Size())
|
|
{
|
|
ptr=queue.Pop();
|
|
if (ptr==0)
|
|
printf("\n");
|
|
else if (ptr->isLeaf==false)
|
|
{
|
|
for (i=0; i < ptr->size+1; i++)
|
|
{
|
|
printf("%p(", ptr->children[i]);
|
|
//printf("(", ptr->children[i]);
|
|
for (j=0; j < ptr->children[i]->size; j++)
|
|
printf("%i ", ptr->children[i]->keys[j]);
|
|
printf(") ");
|
|
queue.Push(ptr->children[i]);
|
|
}
|
|
queue.Push(0);
|
|
printf(" -- ");
|
|
}
|
|
}
|
|
printf("\n");
|
|
}
|
|
}
|
|
#ifdef _MSC_VER
|
|
#pragma warning( pop )
|
|
#endif
|
|
|
|
#endif
|
|
|
|
// Code to test this hellish data structure.
|
|
/*
|
|
#include "DS_BPlusTree.h"
|
|
#include <stdio.h>
|
|
|
|
// Handle underflow on root. If there is only one item left then I can go downwards.
|
|
// Make sure I keep the leftmost pointer valid by traversing it
|
|
// When I free a leaf, be sure to adjust the pointers around it.
|
|
|
|
#include "Rand.h"
|
|
|
|
void main(void)
|
|
{
|
|
DataStructures::BPlusTree<int, int, 16> btree;
|
|
DataStructures::List<int> haveList, removedList;
|
|
int temp;
|
|
int i, j, index;
|
|
int testSize;
|
|
bool b;
|
|
|
|
for (testSize=0; testSize < 514; testSize++)
|
|
{
|
|
printf("TestSize=%i\n", testSize);
|
|
|
|
for (i=0; i < testSize; i++)
|
|
haveList.Insert(i);
|
|
|
|
for (i=0; i < testSize; i++)
|
|
{
|
|
index=i+randomMT()%(testSize-i);
|
|
temp=haveList[index];
|
|
haveList[index]=haveList[i];
|
|
haveList[i]=temp;
|
|
}
|
|
|
|
for (i=0; i<testSize; i++)
|
|
{
|
|
btree.Insert(haveList[i], haveList[i]);
|
|
btree.ValidateTree();
|
|
}
|
|
|
|
for (i=0; i < testSize; i++)
|
|
{
|
|
index=i+randomMT()%(testSize-i);
|
|
temp=haveList[index];
|
|
haveList[index]=haveList[i];
|
|
haveList[i]=temp;
|
|
}
|
|
for (i=0; i<testSize; i++)
|
|
{
|
|
btree.Delete(haveList[0]); // Asserts on 8th call. Fails on going to remove 8 (7th call)
|
|
removedList.Insert(haveList[0]);
|
|
haveList.RemoveAtIndex(0);
|
|
for (j=0; j < removedList.Size(); j++)
|
|
{
|
|
b=btree.Get(removedList[j], temp);
|
|
assert(b==false);
|
|
}
|
|
for (j=0; j < haveList.Size(); j++)
|
|
{
|
|
b=btree.Get(haveList[j], temp);
|
|
assert(b==true);
|
|
assert(haveList[j]==temp);
|
|
}
|
|
assert(btree.Size()==haveList.Size());
|
|
btree.ValidateTree();
|
|
}
|
|
btree.Clear();
|
|
removedList.Clear();
|
|
haveList.Clear();
|
|
}
|
|
|
|
printf("Done. %i\n", btree.Size());
|
|
char ch[256];
|
|
fgets(ch, sizeof(ch), stdin);
|
|
}
|
|
*/
|