/****************************************************************************
 * tree.c
 *
 * Computer Science 50
 * Problem Set 6
 *
 * Implements a tree for Huffman coding.
 ***************************************************************************/

#include <stdlib.h>

#include "tree.h"


/*
 * Tree *
 * mktree()
 *
 * Makes a tree with no children, returning pointer thereto
 * or NULL on error.
 */

Tree *
mktree()
{
    // allocate tree
    Tree *tree = malloc(sizeof(Tree));
    if (tree == NULL)
        return NULL;
    
    // initialize tree
    tree->symbol = 0x00;
    tree->frequency = 0;
    tree->left = NULL;
    tree->right = NULL;

    // return tree
    return tree;
}


/*
 * void
 * rmtree(Tree *t)
 *
 * Deletes a tree and all its descendants, if any.
 */

void
rmtree(Tree *t)
{
    // ensure tree is not NULL
    if (t == NULL)
        return;
    
    // remove left subtree, if any
    if (t->left != NULL)
        rmtree(t->left);

    // remove right subtree, if any
    if (t->right != NULL)
        rmtree(t->right);

    // free root
    free(t);
}