/* the Music Player Daemon (MPD)
* (c)2006 by Warren Dukes (warren.dukes@gmail.com)
* This project's homepage is: http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "tree.h"
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#ifndef CHILDREN_PER_NODE
#define CHILDREN_PER_NODE 3
#endif
#define DATA_PER_NODE (CHILDREN_PER_NODE-1)
#if CHILDREN_PER_NODE > 7
#define USE_BINARY_SEARCH 1
#endif
/************************* DATA STRUCTURES **********************************/
struct _TreeNode
{
void * data[DATA_PER_NODE];
struct _TreeNode * parent;
short parentPos;
struct _TreeNode * children[CHILDREN_PER_NODE];
short dataCount;
};
struct _Tree
{
TreeCompareDataFunction compareData;
TreeFreeDataFunction freeData;
TreeNode * rootNode;
};
/************************* STATIC METHODS ***********************************/
static
TreeNode *
_MakeNode()
{
TreeNode * ret = malloc(sizeof(TreeNode));
memset(ret, 0, sizeof(TreeNode));
return ret;
}
static
int
_FindPosition(Tree * tree, TreeNode * node, void * data, int * pos)
{
#ifdef USE_BINARY_SEARCH
int low = 0;
int high = node->dataCount;
int cmp = -1;
while (high > low)
{
int cur = (high + low) >> 1;
cmp = tree->compareData(data, node->data[cur]);
if (cmp > 0)
{
low = cur+1;
}
else if (cmp < 0)
{
high = cur;
}
else
{
low = cur;
break;
}
}
*pos = low;
return (cmp == 0);
#else
int i = 0;
int cmp = -1;
for (;
i < node->dataCount &&
(cmp = tree->compareData(data, node->data[i])) > 0;
i++);
*pos = i;
return (cmp == 0);
#endif
}
static
int
_Find(TreeIterator * iter, void * data)
{
while (1)
{
if (_FindPosition(iter->tree, iter->node, data, &iter->which))
{
return 1;
}
if (iter->node->children[iter->which])
{
iter->node = iter->node->children[iter->which];
}
else
{
return 0;
}
}
}
static void _SetTreeIteratorToRoot(TreeIterator * iter, Tree * tree)
{
iter->tree = tree;
iter->node = tree->rootNode;
iter->which = 0;
}
static
TreeNode *
_SplitNode(TreeNode * node)
{
assert(node->dataCount == DATA_PER_NODE);
TreeNode * newNode = _MakeNode();
int i = DATA_PER_NODE/2;
int j = 0;
for (; i < DATA_PER_NODE; i++, j++)
{
newNode->data[j] = node->data[i];
newNode->children[j+1] = node->children[i+1];
if (newNode->children[j+1])
{
newNode->children[j+1]->parent = newNode;
newNode->children[j+1]->parentPos = j+1;
}
node->data[i] = NULL;
node->children[i+1] = NULL;
}
newNode->dataCount = (DATA_PER_NODE-DATA_PER_NODE/2);
node->dataCount -= (DATA_PER_NODE-DATA_PER_NODE/2);
return newNode;
}
static
void
_InsertNodeAndData(Tree * tree,
TreeNode * node,
int pos,
TreeNode * newNode,
void * data)
{
assert(node->dataCount < DATA_PER_NODE);
#ifdef TREE_DEBUG
assert(!newNode || tree->compareData(data, newNode->data[0]) < 0);
#endif
int j = node->dataCount;
for (; j > pos; j--)
{
node->data[j] = node->data[j-1];
node->children[j+1] = node->children[j];
if (node->children[j+1])
{
node->children[j+1]->parentPos = j+1;
}
}
#ifdef TREE_DEBUG
assert(!node->children[pos] ||
tree->compareData(data, node->children[pos]->data[0]) > 0);
#endif
node->data[pos] = data;
node->dataCount++;
node->children[pos+1] = newNode;
if (newNode)
{
newNode->parent = node;
newNode->parentPos = pos+1;
}
}
static
void *
_AddDataToSplitNodes(Tree * tree,
TreeNode * lessNode,
TreeNode * moreNode,
int pos,
TreeNode * newNode,
void * data)
{
#ifdef TREE_DEBUG
assert(newNode == NULL ||
tree->compareData(data, newNode->data[0]) < 0);
#endif
assert(moreNode->children[0] == NULL);
void * retData;
if (pos <= lessNode->dataCount)
{
_InsertNodeAndData(tree, lessNode, pos, newNode, data);
lessNode->dataCount--;
retData = lessNode->data[lessNode->dataCount];
lessNode->data[lessNode->dataCount] = NULL;
moreNode->children[0] =
lessNode->children[lessNode->dataCount+1];
if (moreNode->children[0])
{
moreNode->children[0]->parent = moreNode;
moreNode->children[0]->parentPos = 0;
}
lessNode->children[lessNode->dataCount+1] = NULL;
}
else
{
pos -= lessNode->dataCount;
retData = moreNode->data[0];
assert(!moreNode->children[0]);
assert(!moreNode->data[moreNode->dataCount]);
int j = 0;
for (; j < pos; j++)
{
moreNode->data[j] = moreNode->data[j+1];
moreNode->children[j] = moreNode->children[j+1];
if (moreNode->children[j])
{
moreNode->children[j]->parentPos = j;
}
}
assert(!moreNode->children[pos-1] ||
tree->compareData(data,
moreNode->children[pos-1]->data[0]) > 0);
moreNode->data[pos-1] = data;
moreNode->children[pos] = newNode;
if (newNode)
{
newNode->parent = moreNode;
newNode->parentPos = pos;
}
}
return retData;
}
static
void
_InsertAt(TreeIterator * iter, void * data)
{
TreeNode * node = iter->node;
TreeNode * insertNode = NULL;
int pos = iter->which;
while (node != NULL)
{
#ifdef TREE_DEBUG
assert((pos == node->dataCount ||
iter->tree->compareData(data, node->data[pos]) < 0));
#endif
// see if there's any NULL data in the current node
if (node->dataCount == DATA_PER_NODE)
{
// no open data slots, split this node!
TreeNode * newNode = _SplitNode(node);
// insert data in split nodes
data = _AddDataToSplitNodes(iter->tree,
node,
newNode,
pos,
insertNode,
data);
if (node->parent == NULL)
{
assert(node == iter->tree->rootNode);
iter->tree->rootNode = _MakeNode();
iter->tree->rootNode->children[0] = node;
node->parent = iter->tree->rootNode;
node->parentPos = 0;
iter->tree->rootNode->children[1] = newNode;
newNode->parent = iter->tree->rootNode;
newNode->parentPos = 1;
iter->tree->rootNode->data[0] = data;
iter->tree->rootNode->dataCount = 1;
return;
}
pos = node->parentPos;
node = node->parent;
insertNode = newNode;
}
else
{
// insert the data and newNode
_InsertNodeAndData(iter->tree,
node,
pos,
insertNode,
data);
return;
}
}
}
static
void
_MergeNodes(TreeNode * lessNode, TreeNode * moreNode)
{
int i = 0;
int j = lessNode->dataCount;
assert((lessNode->dataCount + moreNode->dataCount) <= DATA_PER_NODE);
assert(lessNode->children[j] == NULL);
for(; i < moreNode->dataCount; i++,j++)
{
assert(!lessNode->children[j]);
assert(!lessNode->data[j]);
lessNode->data[j] = moreNode->data[i];
lessNode->children[j] = moreNode->children[i];
if (lessNode->children[j])
{
lessNode->children[j]->parent = lessNode;
lessNode->children[j]->parentPos = j;
}
}
lessNode->children[j] = moreNode->children[i];
if (lessNode->children[j])
{
lessNode->children[j]->parent = lessNode;
lessNode->children[j]->parentPos = j;
}
lessNode->dataCount += i;
free(moreNode);
}
void
_DeleteAt(TreeIterator * iter)
{
TreeNode * node = iter->node;
int pos = iter->which;
void ** data = &(node->data[pos]);
void * dataToFree = *data;
{
// find the least greater than data to fill the whole!
if (node->children[pos+1])
{
TreeNode * child = node->children[++pos];
while (child->children[0])
{
pos = 0;
child = child->children[0];
}
*data = child->data[0];
data = &(child->data[0]);
node = child;
}
// or the greatest lesser than data to fill the whole!
else if (node->children[pos])
{
TreeNode * child = node->children[pos];
while (child->children[child->dataCount])
{
pos = child->dataCount;
child = child->children[child->dataCount];
}
*data = child->data[child->dataCount-1];
data = &(child->data[child->dataCount-1]);
node = child;
}
else
{
pos = node->parentPos;
}
}
// move data nodes over, we're at a leaf node, so we can ignore
// children
int i = data - node->data;;
for (; i < node->dataCount-1; i++)
{
node->data[i] = node->data[i+1];
}
node->data[--node->dataCount] = NULL;
// merge the nodes from the bottom up which have too few data
while (node->dataCount < (DATA_PER_NODE/2))
{
// if we're not the root
if (node->parent)
{
TreeNode ** child = &(node->parent->children[pos]);
assert(node->parent->children[pos] == node);
// check siblings for extra data
if (pos < node->parent->dataCount &&
(*(child+1))->dataCount > (DATA_PER_NODE/2))
{
child++;
node->data[node->dataCount++] =
node->parent->data[pos];
node->children[node->dataCount] =
(*child)->children[0];
if (node->children[node->dataCount])
{
node->children[node->dataCount]->
parent = node;
node->children[node->dataCount]->
parentPos = node->dataCount;
}
node->parent->data[pos] =
(*child)->data[0];
int i = 0;
for(; i < (*child)->dataCount-1; i++)
{
(*child)->data[i] = (*child)->data[i+1];
(*child)->children[i] =
(*child)->children[i+1];
if ((*child)->children[i])
{
(*child)->children[i]->
parentPos = i;
}
}
(*child)->children[i] = (*child)->children[i+1];
if ((*child)->children[i])
{
(*child)->children[i]->parentPos = i;
}
(*child)->children[i+1] =NULL;
(*child)->data[i] = NULL;
(*child)->dataCount--;
}
else if (pos > 0 &&
(*(child-1))->dataCount>(DATA_PER_NODE/2))
{
child--;
int i = node->dataCount++;
for(; i > 0; i--)
{
node->data[i] = node->data[i-1];
node->children[i+1] = node->children[i];
if (node->children[i+1])
{
node->children[i+1]->parentPos =
i+1;
}
}
node->children[1] = node->children[0];
if (node->children[1])
{
node->children[1]->parentPos = 1;
}
node->data[0] = node->parent->data[pos-1];
node->children[0] =
(*child)->children[(*child)->dataCount];
if (node->children[0])
{
node->children[0]->parent = node;
node->children[0]->parentPos = 0;
}
node->parent->data[pos-1] =
(*child)->data[(*child)->dataCount-1];
(*child)->children[(*child)->dataCount--] =
NULL;
(*child)->data[(*child)->dataCount] = NULL;
}
// merge with one of our siblings
else
{
if (pos < node->parent->dataCount)
{
child++;
assert(*child);
node->data[node->dataCount++] =
node->parent->data[pos];
_MergeNodes(node, *child);
}
else
{
assert(pos > 0);
child--;
assert(*child);
pos--;
(*child)->data[(*child)->dataCount++] =
node->parent->data[pos];
_MergeNodes(*child, node);
node = *child;
}
int i = pos;
for(; i < node->parent->dataCount-1; i++)
{
node->parent->data[i] =
node->parent->data[i+1];
node->parent->children[i+1] =
node->parent->children[i+2];
if (node->parent->children[i+1])
{
node->parent->children[i+1]->
parentPos = i+1;
}
}
node->parent->data[i] = NULL;
node->parent->children[i+1] = NULL;
node->parent->dataCount--;
node = node->parent;
pos = node->parentPos;
}
}
// this is a root node
else
{
if (node->dataCount == 0)
{
if (node->children[0])
{
node->children[0]->parent = NULL;
node->children[0]->parentPos = 0;
}
iter->tree->rootNode = node->children[0];
free(node);
}
break;
}
}
if (iter->tree->freeData)
{
iter->tree->freeData(dataToFree);
}
}
/************************* PUBLIC METHODS ***********************************/
Tree *
MakeTree(TreeCompareDataFunction compareData, TreeFreeDataFunction freeData)
{
Tree * ret = malloc(sizeof(Tree));
ret->compareData = compareData;
ret->freeData = freeData;
ret->rootNode = _MakeNode();
return ret;
}
void SetTreeIteratorToBegin(TreeIterator * iter, Tree * tree)
{
_SetTreeIteratorToRoot(iter, tree);
IncrementTreeIterator(iter);
}
int IsTreeIteratorAtEnd(const TreeIterator * iter)
{
return (iter->node == NULL);
}
void IncrementTreeIterator(TreeIterator * iter)
{
while(iter->node)
{
if (iter->node->children[iter->which])
{
iter->node = iter->node->children[iter->which];
iter->which = 0;
}
else
{
iter->which++;
}
while (iter->node && iter->which > iter->node->dataCount)
{
TreeNode * childNode = iter->node;
iter->node = childNode->parent;
if (iter->node)
{
for (iter->which = 0;
childNode !=
iter->node->children[iter->which];
iter->which++)
{
assert(iter->which <=
iter->node->dataCount);
}
iter->which++;
}
}
if (iter->node &&
iter->which > 0 && iter->which <= iter->node->dataCount)
{
return;
}
}
}
void *
GetDataFromTreeIterator(TreeIterator * iter)
{
assert(iter->node &&
iter->which > 0 &&
iter->which <= iter->node->dataCount);
return iter->node->data[iter->which-1];
}
int
InsertIntoTree(Tree * tree, void * data)
{
TreeIterator iter;
_SetTreeIteratorToRoot(&iter, tree);
if (_Find(&iter, data))
{
return 0;
}
_InsertAt(&iter, data);
return 1;
}
int
DeleteFromTree(Tree * tree, void * data)
{
TreeIterator iter;
_SetTreeIteratorToRoot(&iter, tree);
if (_Find(&iter, data))
{
_DeleteAt(&iter);
return 1;
}
return 0;
}