diff options
Diffstat (limited to 'src/tree.c')
| -rw-r--r-- | src/tree.c | 234 |
1 files changed, 228 insertions, 6 deletions
diff --git a/src/tree.c b/src/tree.c index 58e8a221f..d1f07f74b 100644 --- a/src/tree.c +++ b/src/tree.c @@ -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; } } +} + +static +void +_MergeNodes(TreeNode * lessNode, TreeNode * moreNode) +{ + 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; - return; + free(moreNode); } -static void _SetTreeIteratorToRoot(TreeIterator * iter, Tree * tree) +static +void +_DeleteAt(TreeIterator * iter) { - iter->tree = tree; - iter->node = tree->rootNode; - iter->which = 0; + 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); + } +} |