Generic AVL trees module in C

avl.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "avl.h"

typedef struct treenode{
	BalanceFactor bf;
	void* entry;
	struct treenode *left;
	struct treenode *right;
} TreeNode;

Tree createTree(void){
	return NULL;
}

int compareStrings(void *s1 , void *s2){
	int i=0;
	while(((char*)s1)[i] != '\0' && ((char*)s2)[i] != '\0' && ((char*)s1)[i]==((char*)s2)[i]){
		i++;
	}
	if (((char*)s1)[i]>((char*)s2)[i]) return 1;
	else{
		if (((char*)s1)[i]<((char*)s2)[i]) return -1;
		else return 0;
	}
}

void emptyTree(Tree t){
	if (t==NULL) return;
	emptyTree(t->left);
	emptyTree(t->right);
	free (t);
}

int treeSize(Tree t){
	if(t==NULL)return 0;
	return(treeSize(t->left)+treeSize(t->right)+1);
}

int treeHeight(Tree t){
	if (!t) return 0;
	else{
		if(t->bf==LH) return 1 + treeHeight(t->left);
		else return 1 + treeHeight(t->right);
	} 
}

int isEmpty(Tree t){
	if (t==NULL) return 1;
	else return 0;
}

int searchKey(Tree t, void* e, int (*f)(void* , void*)){
	if(t==NULL) return 0;
	if(f(t->entry,e)==0) return 1;
	else if(f(t->entry,e)==1) return(searchKey(t->left, e, f));
	else return(searchKey(t->right, e, f));
}

Tree rotateRight(Tree t){
	Tree aux;
	aux = createTree();
	if ((! t)||(! t->left)){
	}
	else{
		aux=t->left;
		t->left=aux->right;
		aux->right=t;
		t=aux;
	}
	return t;
}

Tree rotateLeft(Tree t){
	Tree aux;
	aux = createTree();
	if((! t)||(! t->right)){
	}
	else{
		aux=t->right;
		t->right=aux->left;
		aux->left=t;
		t=aux;
	}
	return t;
}

Tree balanceRight(Tree t){
	if(t->right->bf==RH){
		t=rotateLeft(t);
		t->bf=EH;
		t->left->bf=EH;
	}
	else{
		t->right=rotateRight(t->right);
		t=rotateLeft(t);
		switch (t->bf) {
			case EH:
				t->left->bf=EH;
				t->right->bf=EH;
				break;
			case LH:
				t->left->bf=EH;
				t->right->bf=RH;
				break;
			case RH:
				t->left->bf=LH;
				t->right->bf=EH;
		}
		t->bf=EH;
	}
	return t;
}

Tree balanceLeft(Tree t){
	if (t->left->bf==LH){
		t=rotateRight(t);
		t->bf=EH;
		t->right->bf=EH;
	}
	else{
		t->left=rotateLeft(t->left);
		t=rotateRight(t);
		switch (t->bf) {
		case EH:
			t->left->bf=EH;
			t->right->bf=EH;
			break;
		case RH:
			t->left->bf=LH;
			t->right->bf=EH;
			break;
		case LH:
			t->left->bf=EH;
			t->right->bf=RH;
		}
		t->bf=EH;
	}
	return t;
}

Tree insertTree(Tree t, void* e, int *cresceu, int (*f)(void* , void*));

Tree insertRight(Tree t, void* e, int *cresceu, int (*f)(void* , void*)){
	t->right=insertTree(t->right, e, cresceu, f);
	if(*cresceu){
		switch (t->bf) {
			case LH:
				t->bf=EH;
				*cresceu=0;
				break;
			case EH:
				t->bf=RH;
				*cresceu=1;
				break;
			case RH:
				t=balanceRight(t);
				*cresceu=0;
		}
	}
	return t;
}

Tree insertLeft(Tree t, void* e, int *cresceu, int (*f)(void* , void*)){
	t->left=insertTree(t->left, e, cresceu, f);
	if (*cresceu) {
		switch (t->bf) {
			case RH:
				t->bf=EH;
				*cresceu=0;
				break;
			case EH:
				t->bf=LH;
				*cresceu=1;
				break;
			case LH:
				t=balanceLeft(t);
				*cresceu=0;
		}
	}
	return t;
}

Tree insertTree(Tree t, void* e, int *cresceu, int (*f)(void* , void*)){
	if(t==NULL){
		t=(Tree)malloc(sizeof(struct treenode));
		t->entry=e;
		t->right=NULL;
		t->left=NULL;
		t->bf=EH;
		*cresceu=1;
	}
	else if(f(e,t->entry)==0){
	}
	else if(f(e,t->entry)==1){
		t=insertRight(t,e,cresceu, f);
	}
	else{
		t=insertLeft(t,e,cresceu, f);
	}
	return(t);
}

void TreeToArrayStrings(Tree t, int *pos, int linesize, char** array, char* (*toStr)(void*)){
    if(t){
		char* buf;
		TreeToArrayStrings(t->left, pos, linesize, array, toStr);
		array[*pos] = (char*)malloc(sizeof(char)*linesize);
		buf = toStr(t->entry);
		strcpy(array[*pos], buf);
		(*pos)++;
		TreeToArrayStrings(t->right, pos, linesize, array, toStr);
    }
}