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-rw-r--r--src/tree.c260
-rw-r--r--src/tree.h36
2 files changed, 296 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;
+}
diff --git a/src/tree.h b/src/tree.h
new file mode 100644
index 000000000..737f914d2
--- /dev/null
+++ b/src/tree.h
@@ -0,0 +1,36 @@
+#define CHILDREN_PER_NODE 3
+#define DATA_PER_NODE 2
+
+typedef struct _TreeNode
+{
+ void * data[DATA_PER_NODE];
+ struct _TreeNode * parent;
+ struct _TreeNode * children[CHILDREN_PER_NODE];
+ unsigned dataCount;
+} TreeNode;
+
+typedef int (*TreeCompareDataFunction)(void * data1, void * data2);
+typedef void (*TreeFreeDataFunction)(void * data);
+
+typedef struct _Tree
+{
+ TreeCompareDataFunction compareData;
+ TreeFreeDataFunction freeData;
+ TreeNode * rootNode;
+} Tree;
+
+typedef struct _TreeIterator
+{
+ Tree * tree;
+ TreeNode * node;
+ unsigned which;
+} TreeIterator;
+
+Tree * MakeTree(TreeCompareDataFunction compareFunc,
+ TreeFreeDataFunction freeData);
+
+void SetIteratorToBegin(TreeIterator * iter, Tree * tree);
+
+int InsertIntoTree(Tree * tree, void * data);
+
+void DeleteFromTree(Tree * tree, void * data);
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-02 02:04:15 +0000