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*) add copyright notice
*) implemented node deletion, but not yet tested

git-svn-id: https://svn.musicpd.org/mpd/trunk@4496 09075e82-0dd4-0310-85a5-a0d7c8717e4f
This commit is contained in:
Warren Dukes 2006-07-31 02:20:44 +00:00
parent 44f9e16922
commit 43fbf992e2
2 changed files with 247 additions and 7 deletions
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236
src/tree.c
View File

@ -1,9 +1,26 @@
/* 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>
#include <stdio.h>
#ifndef CHILDREN_PER_NODE
#define CHILDREN_PER_NODE 3
@ -111,6 +128,13 @@ _Find(TreeIterator * iter, void * data)
}
}
static void _SetTreeIteratorToRoot(TreeIterator * iter, Tree * tree)
{
iter->tree = tree;
iter->node = tree->rootNode;
iter->which = 0;
}
static
TreeNode *
_SplitNode(TreeNode * node)
@ -313,15 +337,201 @@ _InsertAt(TreeIterator * iter, void * data)
node = NULL;
}
}
return;
}
static void _SetTreeIteratorToRoot(TreeIterator * iter, Tree * tree)
static
void
_MergeNodes(TreeNode * lessNode, TreeNode * moreNode)
{
iter->tree = tree;
iter->node = tree->rootNode;
iter->which = 0;
int i = 0;
int j = lessNode->dataCount;
assert((lessNode->dataCount + moreNode->dataCount) <= DATA_PER_NODE);
for(; i < moreNode->dataCount; i++,j++)
{
lessNode->data[j] = moreNode->data[i];
lessNode->children[j] = moreNode->children[i];
lessNode->children[j]->parent = lessNode;
}
lessNode->children[j] = moreNode->children[i];
lessNode->children[j]->parent = lessNode;
lessNode->dataCount = j;
free(moreNode);
}
static
void
_DeleteAt(TreeIterator * iter)
{
TreeNode * node = iter->node;
void ** data = &(node->data[iter->which]);
void * dataToFree = *data;
// perculate up data to fill the whole!
while (1)
{
TreeNode ** child = &(node->children[iter->which+1]);
void ** childData = NULL;
if (*child)
{
assert((*child)->dataCount);
childData = &((*child)->data[0]);
}
else if (*(--child))
{
assert((*child)->dataCount);
childData = &((*child)->data[(*child)->dataCount-1]);
}
else
{
// no children!
break;
}
// move childData up to parent node
*data = *childData;
// set data and node for next iteration
data = childData;
node = *child;
}
void * tempData = *data;
// move data nodes over, we're at a leaf node, so we can ignore
// children
void ** leftData = node->data[node->dataCount-1];
while (data != leftData)
{
*(leftData-1) = *leftData;
leftData--;
}
node->data[--(node->dataCount)] = NULL;
// merge the nodes from the bottom up which have too few data
while (node->dataCount < (CHILDREN_PER_NODE/2))
{
// if we're not the root
if (node->parent)
{
TreeNode ** child;
int pos;
_FindPositionInNode(iter->tree,
node->parent,
tempData,
&pos);
assert(node->parent->children[pos] == node);
child = &(node->parent->children[pos]);
// check siblings for superfulous data
if (pos < node->parent->dataCount &&
(*(child+1))->dataCount > (CHILDREN_PER_NODE/2))
{
child++;
node->data[node->dataCount++] =
node->parent->data[pos];
node->children[node->dataCount] =
(*child)->children[0];
node->children[node->dataCount]->parent = node;
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+1] =
(*child)->children[i+2];
}
(*child)->children[(*child)->dataCount--] =NULL;
(*child)->data[(*child)->dataCount] = NULL;
}
else if (pos > 0 &&
(*(child-1))->dataCount>(CHILDREN_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];
}
node->data[0] = node->parent->data[pos-1];
node->children[0] =
(*child)->children[(*child)->dataCount];
node->children[0]->parent = node;
node->parent->data[pos-1] =
(*child)->data[(*child)->dataCount-1];
(*child)->children[(*child)->dataCount--] =NULL;
(*child)->data[(*child)->dataCount] = NULL;
}
else
{
// merge with one of our siblings
if(pos < node->parent->dataCount-1)
{
child++;
assert(*child);
pos--;
tempData = node->parent->data[pos];
node->data[node->dataCount++] =
tempData;
_MergeNodes(node, *child);
}
else
{
assert(pos > 0);
child--;
assert(*child);
tempData = node->parent->data[pos];
(*child)->data[(*child)->dataCount++] =
tempData;
_MergeNodes(*child, node);
}
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];
}
node->parent->data[i] = NULL;
node->parent->children[i+1] = NULL;
node = node->parent;
}
}
// this is a root node
else
{
if (node->dataCount == 0)
{
if (node->children[0])
{
node->children[0]->parent = NULL;
}
iter->tree->rootNode = node->children[0];
free(node);
}
break;
}
}
if (iter->tree->freeData)
{
iter->tree->freeData(dataToFree);
}
}
/************************* PUBLIC METHODS ***********************************/
@ -411,3 +621,15 @@ InsertIntoTree(Tree * tree, void * data)
return 1;
}
void
DeleteFromTree(Tree * tree, void * data)
{
TreeIterator iter;
_SetTreeIteratorToRoot(&iter, tree);
if (_Find(&iter, data))
{
_DeleteAt(&iter);
}
}

18
src/tree.h
View File

@ -1,3 +1,21 @@
/* 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
*/
#ifndef TREE_H
#define TREE_H