Doble_Info2/bintree.c

#include <stdlib.h>
#include <string.h>
#include "stack.h"
#include "bintree.h"

//TODO: binären Suchbaum implementieren
/*  * `addToTree`: fügt ein neues Element in den Baum ein (rekursiv),
    * `clearTree`: gibt den gesamten Baum frei (rekursiv),
    * `treeSize`: zählt die Knoten im Baum (rekursiv),
    * `nextTreeData`: Traversierung mit Hilfe des zuvor implementierten Stacks. */

// Adds a copy of data's pointer destination to the tree using compareFct for ordering. Accepts duplicates
// if isDuplicate is NULL, otherwise ignores duplicates and sets isDuplicate to 1 (or to 0 if a new entry is added).
TreeNode *addToTree(TreeNode *root, const void *data, size_t dataSize, CompareFctType compareFct, int *isDuplicate)
{
    if (root == NULL) {
        TreeNode *newNode = (TreeNode *)malloc(sizeof(TreeNode));
        if (newNode == NULL) {
            return NULL;
        }

        newNode->data = malloc(dataSize);
        if (newNode->data == NULL) {
            free(newNode);
            return NULL;
        }
        memcpy(newNode->data, data, dataSize);
        newNode->left = NULL;
        newNode->right = NULL;

        if (isDuplicate != NULL) {
            *isDuplicate = 0;
        }
        return newNode;
    }

    int cmp = compareFct(data, root->data);

    if (cmp == 0 && isDuplicate != NULL) {
        *isDuplicate = 1;
        return root;
    }

    if (cmp < 0) {
        root->left = addToTree(root->left, data, dataSize, compareFct, isDuplicate);
    } else {
        /* Insert duplicates on the right side if they are allowed (isDuplicate == NULL). */
        root->right = addToTree(root->right, data, dataSize, compareFct, isDuplicate);
    }

    return root;
}

// Iterates over the tree given by root. Follows the usage of strtok. If tree is NULL, the next entry of the last tree given is returned in ordering direction.
// Use your implementation of a stack to organize the iterator. Push the root node and all left nodes first. On returning the next element,
// push the top node and push all its left nodes.
void *nextTreeData(TreeNode *root)
{

    static StackNode *iterStack = NULL;

    // Start of traversal
    if (root != NULL) {
        clearStack(iterStack);
        iterStack = NULL;

        for (TreeNode *n = root; n != NULL; n = n->left) {
            iterStack = push(iterStack, n);
        }
    }

    // Stops if no elements left
    if (iterStack == NULL) {
        return NULL;
    }

    // Pop the top node
    TreeNode *node = (TreeNode *)top(iterStack);
    iterStack = pop(iterStack);

    // select node one to the right --> push all lefts
    for (TreeNode *n = node->right; n != NULL; n = n->left) {
        iterStack = push(iterStack, n);
    }

    return node->data;
}

// Releases all memory resources (including data copies).
void clearTree(TreeNode *root)
{
    if (root != NULL) {
        clearTree(root->left);
        clearTree(root->right);
        free(root->data);
        free(root);
    }
}

// Returns the number of entries in the tree given by root.
unsigned int treeSize(const TreeNode *root)
{
    if (root == NULL) {
        return 0;
    }
    return 1 + treeSize(root->left) + treeSize(root->right);
}