DarkflameServer/thirdparty/raknet/Source/DS_BPlusTree.h

1163 lines
32 KiB
C
Raw Normal View History

#ifndef __B_PLUS_TREE_CPP
#define __B_PLUS_TREE_CPP
#include "DS_MemoryPool.h"
#include "DS_Queue.h"
#include <stdio.h>
#include "Export.h"
// Java
// http://www.seanster.com/BplusTree/BplusTree.html
// Overview
// http://babbage.clarku.edu/~achou/cs160/B+Trees/B+Trees.htm
// Deletion
// http://dbpubs.stanford.edu:8090/pub/1995-19
#ifdef _MSC_VER
#pragma warning( push )
#endif
#include "RakMemoryOverride.h"
/// The namespace DataStructures was only added to avoid compiler errors for commonly named data structures
/// As these data structures are stand-alone, you can use them outside of RakNet for your own projects if you wish.
namespace DataStructures
{
/// Used in the BPlusTree. Used for both leaf and index nodes.
/// Don't use a constructor or destructor, due to the memory pool I am using
template <class KeyType, class DataType, int order>
struct RAK_DLL_EXPORT Page : public RakNet::RakMemoryOverride
{
// We use the same data structure for both leaf and index nodes. It uses a little more memory for index nodes but reduces
// memory fragmentation, allocations, and deallocations.
bool isLeaf;
// Used for both leaf and index nodes.
// For a leaf it means the number of elements in data
// For an index it means the number of keys and is one less than the number of children pointers.
int size;
// Used for both leaf and index nodes.
KeyType keys[order];
// Used only for leaf nodes. Data is the actual data, while next is the pointer to the next leaf (for B+)
DataType data[order];
Page<KeyType, DataType, order> *next;
Page<KeyType, DataType, order> *previous;
// Used only for index nodes. Pointers to the children of this node.
Page *children[order+1];
};
/// A BPlus tree
/// Written with efficiency and speed in mind.
template <class KeyType, class DataType, int order>
class RAK_DLL_EXPORT BPlusTree : public RakNet::RakMemoryOverride
{
public:
struct ReturnAction
{
KeyType key1;
KeyType key2;
enum
{
NO_ACTION,
REPLACE_KEY1_WITH_KEY2,
PUSH_KEY_TO_PARENT,
SET_BRANCH_KEY,
} action; // 0=none, 1=replace key1 with key2
};
BPlusTree();
~BPlusTree();
void SetPoolPageSize(int size); // Set the page size for the memory pool. Optionsl
bool Get(const KeyType key, DataType &out) const;
bool Delete(const KeyType key);
bool Delete(const KeyType key, DataType &out);
bool Insert(const KeyType key, const DataType &data);
void Clear(void);
unsigned Size(void) const;
bool IsEmpty(void) const;
Page<KeyType, DataType, order> *GetListHead(void) const;
DataType GetDataHead(void) const;
void PrintLeaves(void);
void ForEachLeaf(void (*func)(Page<KeyType, DataType, order> * leaf, int index));
void ForEachData(void (*func)(DataType input, int index));
void PrintGraph(void);
void ValidateTree(void);
protected:
void ValidateTreeRecursive(Page<KeyType, DataType, order> *cur);
void DeleteFromPageAtIndex(const int index, Page<KeyType, DataType, order> *cur);
static void PrintLeaf(Page<KeyType, DataType, order> * leaf, int index);
void FreePages(void);
bool GetIndexOf(const KeyType key, Page<KeyType, DataType, order> *page, int *out) const;
void ShiftKeysLeft(Page<KeyType, DataType, order> *cur);
bool CanRotateLeft(Page<KeyType, DataType, order> *cur, int childIndex);
bool CanRotateRight(Page<KeyType, DataType, order> *cur, int childIndex);
void RotateRight(Page<KeyType, DataType, order> *cur, int childIndex, ReturnAction *returnAction);
void RotateLeft(Page<KeyType, DataType, order> *cur, int childIndex, ReturnAction *returnAction);
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);
Page<KeyType, DataType, order>* InsertBranchDown(const KeyType key, const DataType &data,Page<KeyType, DataType, order> *cur, ReturnAction* returnAction, bool *success);
Page<KeyType, DataType, order>* GetLeafFromKey(const KeyType key) const;
bool FindDeleteRebalance(const KeyType key, Page<KeyType, DataType, order> *cur, bool *underflow, KeyType rightRootKey, ReturnAction *returnAction, DataType &out);
bool FixUnderflow(int branchIndex, Page<KeyType, DataType, order> *cur, KeyType rightRootKey, ReturnAction *returnAction);
void ShiftNodeLeft(Page<KeyType, DataType, order> *cur);
void ShiftNodeRight(Page<KeyType, DataType, order> *cur);
MemoryPool<Page<KeyType, DataType, order> > pagePool;
Page<KeyType, DataType, order> *root, *leftmostLeaf;
};
template<class KeyType, class DataType, int order>
BPlusTree<KeyType, DataType, order>::BPlusTree ()
{
assert(order>1);
root=0;
leftmostLeaf=0;
}
template<class KeyType, class DataType, int order>
BPlusTree<KeyType, DataType, order>::~BPlusTree ()
{
Clear();
}
template<class KeyType, class DataType, int order>
void BPlusTree<KeyType, DataType, order>::SetPoolPageSize(int size)
{
pagePool.SetPageSize(size);
}
template<class KeyType, class DataType, int order>
bool BPlusTree<KeyType, DataType, order>::Get(const KeyType key, DataType &out) const
{
if (root==0)
return false;
Page<KeyType, DataType, order>* leaf = GetLeafFromKey(key);
int childIndex;
if (GetIndexOf(key, leaf, &childIndex))
{
out=leaf->data[childIndex];
return true;
}
return false;
}
template<class KeyType, class DataType, int order>
void BPlusTree<KeyType, DataType, order>::DeleteFromPageAtIndex(const int index, Page<KeyType, DataType, order> *cur)
{
int i;
for (i=index; i < cur->size-1; i++)
cur->keys[i]=cur->keys[i+1];
if (cur->isLeaf)
{
for (i=index; i < cur->size-1; i++)
cur->data[i]=cur->data[i+1];
}
else
{
for (i=index; i < cur->size-1; i++)
cur->children[i+1]=cur->children[i+2];
}
cur->size--;
}
template<class KeyType, class DataType, int order>
bool BPlusTree<KeyType, DataType, order>::Delete(const KeyType key)
{
DataType temp;
return Delete(key, temp);
}
template<class KeyType, class DataType, int order>
bool BPlusTree<KeyType, DataType, order>::Delete(const KeyType key, DataType &out)
{
if (root==0)
return false;
ReturnAction returnAction;
returnAction.action=ReturnAction::NO_ACTION;
int childIndex;
bool underflow=false;
if (root==leftmostLeaf)
{
if (GetIndexOf(key, root, &childIndex)==false)
return false;
out=root->data[childIndex];
DeleteFromPageAtIndex(childIndex,root);
if (root->size==0)
{
pagePool.Release(root);
root=0;
leftmostLeaf=0;
}
return true;
}
else if (FindDeleteRebalance(key, root, &underflow,root->keys[0], &returnAction, out)==false)
return false;
// assert(returnAction.action==ReturnAction::NO_ACTION);
if (underflow && root->size==0)
{
// Move the root down.
Page<KeyType, DataType, order> *oldRoot=root;
root=root->children[0];
pagePool.Release(oldRoot);
// memset(oldRoot,0,sizeof(root));
}
return true;
}
template<class KeyType, class DataType, int order>
bool BPlusTree<KeyType, DataType, order>::FindDeleteRebalance(const KeyType key, Page<KeyType, DataType, order> *cur, bool *underflow, KeyType rightRootKey, ReturnAction *returnAction, DataType &out)
{
// Get index of child to follow.
int branchIndex, childIndex;
if (GetIndexOf(key, cur, &childIndex))
branchIndex=childIndex+1;
else
branchIndex=childIndex;
// If child is not a leaf, call recursively
if (cur->children[branchIndex]->isLeaf==false)
{
if (branchIndex<cur->size)
rightRootKey=cur->keys[branchIndex]; // Shift right to left
else
rightRootKey=cur->keys[branchIndex-1]; // Shift center to left
if (FindDeleteRebalance(key, cur->children[branchIndex], underflow, rightRootKey, returnAction, out)==false)
return false;
// Call again in case the root key changed
if (branchIndex<cur->size)
rightRootKey=cur->keys[branchIndex]; // Shift right to left
else
rightRootKey=cur->keys[branchIndex-1]; // Shift center to left
if (returnAction->action==ReturnAction::SET_BRANCH_KEY && branchIndex!=childIndex)
{
returnAction->action=ReturnAction::NO_ACTION;
cur->keys[childIndex]=returnAction->key1;
if (branchIndex<cur->size)
rightRootKey=cur->keys[branchIndex]; // Shift right to left
else
rightRootKey=cur->keys[branchIndex-1]; // Shift center to left
}
}
else
{
// If child is a leaf, get the index of the key. If the item is not found, cancel delete.
if (GetIndexOf(key, cur->children[branchIndex], &childIndex)==false)
return false;
// Delete:
// Remove childIndex from the child at branchIndex
out=cur->children[branchIndex]->data[childIndex];
DeleteFromPageAtIndex(childIndex, cur->children[branchIndex]);
if (childIndex==0)
{
if (branchIndex>0)
cur->keys[branchIndex-1]=cur->children[branchIndex]->keys[0];
if (branchIndex==0)
{
returnAction->action=ReturnAction::SET_BRANCH_KEY;
returnAction->key1=cur->children[0]->keys[0];
}
}
if (cur->children[branchIndex]->size < order/2)
*underflow=true;
else
*underflow=false;
}
// Fix underflow:
if (*underflow)
{
*underflow=FixUnderflow(branchIndex, cur, rightRootKey, returnAction);
}
return true;
}
template<class KeyType, class DataType, int order>
bool BPlusTree<KeyType, DataType, order>::FixUnderflow(int branchIndex, Page<KeyType, DataType, order> *cur, KeyType rightRootKey, ReturnAction *returnAction)
{
// Borrow from a neighbor that has excess.
Page<KeyType, DataType, order> *source;
Page<KeyType, DataType, order> *dest;
if (branchIndex>0 && cur->children[branchIndex-1]->size > order/2)
{
dest=cur->children[branchIndex];
source=cur->children[branchIndex-1];
// Left has excess
ShiftNodeRight(dest);
if (dest->isLeaf)
{
dest->keys[0]=source->keys[source->size-1];
dest->data[0]=source->data[source->size-1];
}
else
{
dest->children[0]=source->children[source->size];
dest->keys[0]=cur->keys[branchIndex-1];
}
// Update the parent key for the child (middle)
cur->keys[branchIndex-1]=source->keys[source->size-1];
source->size--;
// if (branchIndex==0)
// {
// returnAction->action=ReturnAction::SET_BRANCH_KEY;
// returnAction->key1=dest->keys[0];
// }
// No underflow
return false;
}
else if (branchIndex<cur->size && cur->children[branchIndex+1]->size > order/2)
{
dest=cur->children[branchIndex];
source=cur->children[branchIndex+1];
// Right has excess
if (dest->isLeaf)
{
dest->keys[dest->size]=source->keys[0];
dest->data[dest->size]=source->data[0];
// The first key in the leaf after shifting is the parent key for the right branch
cur->keys[branchIndex]=source->keys[1];
#ifdef _MSC_VER
#pragma warning( disable : 4127 ) // warning C4127: conditional expression is constant
#endif
if (order<=3 && dest->size==0)
{
if (branchIndex==0)
{
returnAction->action=ReturnAction::SET_BRANCH_KEY;
returnAction->key1=dest->keys[0];
}
else
cur->keys[branchIndex-1]=cur->children[branchIndex]->keys[0];
}
}
else
{
if (returnAction->action==ReturnAction::NO_ACTION)
{
returnAction->action=ReturnAction::SET_BRANCH_KEY;
returnAction->key1=dest->keys[0];
}
dest->keys[dest->size]=rightRootKey;
dest->children[dest->size+1]=source->children[0];
// The shifted off key is the leftmost key for a node
cur->keys[branchIndex]=source->keys[0];
}
dest->size++;
ShiftNodeLeft(source);
//cur->keys[branchIndex]=source->keys[0];
// returnAction->action=ReturnAction::SET_BRANCH_KEY;
// returnAction->key1=dest->keys[dest->size-1];
// No underflow
return false;
}
else
{
int sourceIndex;
// If no neighbors have excess, merge two branches.
//
// To merge two leaves, just copy the data and keys over.
//
// To merge two branches, copy the pointers and keys over, using rightRootKey as the key for the extra pointer
if (branchIndex<cur->size)
{
// Merge right child to current child and delete right child.
dest=cur->children[branchIndex];
source=cur->children[branchIndex+1];
}
else
{
// Move current child to left and delete current child
dest=cur->children[branchIndex-1];
source=cur->children[branchIndex];
}
// Merge
if (dest->isLeaf)
{
for (sourceIndex=0; sourceIndex<source->size; sourceIndex++)
{
dest->keys[dest->size]=source->keys[sourceIndex];
dest->data[dest->size++]=source->data[sourceIndex];
}
}
else
{
// We want the tree root key of the source, not the current.
dest->keys[dest->size]=rightRootKey;
dest->children[dest->size++ + 1]=source->children[0];
for (sourceIndex=0; sourceIndex<source->size; sourceIndex++)
{
dest->keys[dest->size]=source->keys[sourceIndex];
dest->children[dest->size++ + 1]=source->children[sourceIndex + 1];
}
}
#ifdef _MSC_VER
#pragma warning( disable : 4127 ) // warning C4127: conditional expression is constant
#endif
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.
cur->keys[branchIndex-1]=cur->children[branchIndex]->keys[0];
if (branchIndex<cur->size)
{
// Update the parent key, removing the source (right)
DeleteFromPageAtIndex(branchIndex, cur);
}
else
{
if (branchIndex>0)
{
// Update parent key, removing the source (current)
DeleteFromPageAtIndex(branchIndex-1, cur);
}
}
if (branchIndex==0 && dest->isLeaf)
{
returnAction->action=ReturnAction::SET_BRANCH_KEY;
returnAction->key1=dest->keys[0];
}
if (source==leftmostLeaf)
leftmostLeaf=source->next;
if (source->isLeaf)
{
if (source->previous)
source->previous->next=source->next;
if (source->next)
source->next->previous=source->previous;
}
// Free the source node
pagePool.Release(source);
// memset(source,0,sizeof(root));
// Return underflow or not of parent.
return cur->size < order/2;
}
}
template<class KeyType, class DataType, int order>
void BPlusTree<KeyType, DataType, order>::ShiftNodeRight(Page<KeyType, DataType, order> *cur)
{
int i;
for (i=cur->size; i>0; i--)
cur->keys[i]=cur->keys[i-1];
if (cur->isLeaf)
{
for (i=cur->size; i>0; i--)
cur->data[i]=cur->data[i-1];
}
else
{
for (i=cur->size+1; i>0; i--)
cur->children[i]=cur->children[i-1];
}
cur->size++;
}
template<class KeyType, class DataType, int order>
void BPlusTree<KeyType, DataType, order>::ShiftNodeLeft(Page<KeyType, DataType, order> *cur)
{
int i;
for (i=0; i < cur->size-1; i++)
cur->keys[i]=cur->keys[i+1];
if (cur->isLeaf)
{
for (i=0; i < cur->size; i++)
cur->data[i]=cur->data[i+1];
}
else
{
for (i=0; i < cur->size; i++)
cur->children[i]=cur->children[i+1];
}
cur->size--;
}
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);
}
*/