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authorWarren Dukes <warren.dukes@gmail.com>2006-07-30 07:58:56 +0000
committerWarren Dukes <warren.dukes@gmail.com>2006-07-30 07:58:56 +0000
commita0c8e3656ba1c7c796f47f7d020f448961b1b3c5 (patch)
treed113b71ab4c5a5db448cb4e0bdbcf4b2f38f60e7 /src/tree.c
parentb38c3fa1bbd67bcae1718fc9fe0cb42a9a5d1f6c (diff)
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beginnings of a B-tree, currently insertion has been implemented and test
git-svn-id: https://svn.musicpd.org/mpd/trunk@4487 09075e82-0dd4-0310-85a5-a0d7c8717e4f
Diffstat (limited to 'src/tree.c')
-rw-r--r--src/tree.c260
1 files changed, 260 insertions, 0 deletions
diff --git a/src/tree.c b/src/tree.c
new file mode 100644
index 000000000..0696f4b13
--- /dev/null
+++ b/src/tree.c
@@ -0,0 +1,260 @@
+#include "tree.h"
+
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+static
+TreeNode *
+_MakeNode()
+{
+ TreeNode * ret = malloc(sizeof(TreeNode));
+ memset(ret, 0, sizeof(TreeNode));
+ return ret;
+}
+
+static
+int
+_Find(TreeIterator * iter, void * data)
+{
+ while (1)
+ {
+ for (; iter->which < iter->node->dataCount; iter->which++)
+ {
+ int comp = iter->tree->
+ compareData(data,iter->node->data[iter->which]);
+
+ if (comp == 0)
+ {
+ return 1;
+ }
+ else if (comp < 0)
+ {
+ break;
+ }
+ }
+
+ assert(iter->which < CHILDREN_PER_NODE);
+
+ if (iter->node->children[iter->which])
+ {
+ iter->node = iter->node->children[iter->which];
+ iter->which = 0;
+ }
+ else
+ {
+ return 0;
+ }
+ }
+}
+
+Tree *
+MakeTree(TreeCompareDataFunction compareData, TreeFreeDataFunction freeData)
+{
+ Tree * ret = malloc(sizeof(Tree));
+ ret->compareData = compareData;
+ ret->freeData = freeData;
+ ret->rootNode = _MakeNode();
+ return ret;
+}
+
+static
+TreeNode *
+_SplitNode(TreeNode * node)
+{
+ assert(node->dataCount == DATA_PER_NODE);
+
+ TreeNode * newNode = _MakeNode();
+
+ unsigned i = DATA_PER_NODE/2;
+ unsigned 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;
+ }
+ node->data[i] = NULL;
+ node->children[i+1] = NULL;
+ }
+ newNode->dataCount = j;
+ node->dataCount -= j;
+
+ return newNode;
+}
+
+static
+void
+_InsertNodeAndData(Tree * tree,
+ TreeNode * node,
+ TreeNode * newNode,
+ void * data)
+{
+ assert(node->dataCount < DATA_PER_NODE);
+ assert(!newNode || tree->compareData(data, newNode->data[0]) < 0);
+
+ if (newNode)
+ {
+ newNode->parent = node;
+ }
+
+ int i = 0;
+ for (;
+ i < node->dataCount &&
+ tree->compareData(data, node->data[i]) > 0;
+ i++);
+
+ int j = node->dataCount;
+ for (; j > i; j--)
+ {
+ node->data[j] = node->data[j-1];
+ node->children[j+1] = node->children[j];
+ }
+
+ assert(!node->children[j] ||
+ tree->compareData(data, node->children[j]->data[0]) > 0);
+
+ node->data[j] = data;
+ node->children[j+1] = newNode;
+ node->dataCount++;
+}
+
+static
+void *
+_AddDataToSplitNodes(Tree * tree,
+ TreeNode * lessNode,
+ TreeNode * moreNode,
+ TreeNode * newNode,
+ void * data)
+{
+ assert(newNode == NULL ||
+ tree->compareData(data, newNode->data[0]) < 0);
+
+ void * retData;
+
+ if (tree->compareData(data, moreNode->data[0]) < 0)
+ {
+ _InsertNodeAndData(tree, lessNode, newNode, data);
+ lessNode->dataCount--;
+ retData = lessNode->data[lessNode->dataCount];
+ lessNode->data[lessNode->dataCount] = NULL;
+ }
+ else
+ {
+ if (newNode)
+ {
+ newNode->parent = moreNode;
+ }
+
+ int i = 0;
+ for (;
+ i < moreNode->dataCount &&
+ tree->compareData(data, moreNode->data[i]) > 0;
+ i++);
+
+ if (i == 0)
+ {
+ moreNode->children[0] = newNode;
+ return data;
+ }
+ else
+ {
+ retData = moreNode->data[0];
+ }
+
+ int j = 0;
+ for (; j < i; j++)
+ {
+ moreNode->data[j] = moreNode->data[j+1];
+ moreNode->children[j] = moreNode->children[j+1];
+ }
+
+ assert(!moreNode->children[j-1] ||
+ tree->compareData(data,
+ moreNode->children[j]->data[0]) > 0);
+
+ moreNode->data[j-1] = data;
+ moreNode->children[j] = newNode;
+ }
+
+ return retData;
+}
+
+static
+void
+_InsertAt(TreeIterator * iter, void * data)
+{
+ TreeNode * node = iter->node;
+ TreeNode * insertNode = NULL;
+
+ while (node != NULL)
+ {
+ // 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,
+ insertNode,
+ data);
+
+ insertNode = newNode;
+
+ if (node->parent == NULL)
+ {
+ assert(node == iter->tree->rootNode);
+ iter->tree->rootNode = _MakeNode();
+ node->parent = iter->tree->rootNode;
+ newNode->parent = iter->tree->rootNode;
+ iter->tree->rootNode->data[0] = data;
+ iter->tree->rootNode->children[0] = node;
+ iter->tree->rootNode->children[1] = newNode;
+ iter->tree->rootNode->dataCount = 1;
+ return;
+ }
+
+ node = node->parent;
+ }
+ else
+ {
+ // insert the data and newNode
+ _InsertNodeAndData( iter->tree,
+ node,
+ insertNode,
+ data );
+ node = NULL;
+ }
+ }
+
+ return;
+}
+
+void SetIteratorToBegin(TreeIterator * iter, Tree * tree)
+{
+ iter->tree = tree;
+ iter->node = tree->rootNode;
+ iter->which = 0;
+}
+
+int
+InsertIntoTree(Tree * tree, void * data)
+{
+ TreeIterator iter;
+ SetIteratorToBegin(&iter, tree);
+
+ if (_Find(&iter, data))
+ {
+ return 0;
+ }
+
+ _InsertAt(&iter, data);
+
+ return 1;
+}