/*
 * Paul Heidelman
 * Case Western Reserve University
 * EECS 337 Fall 2009
 * Homework 2
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>


typedef struct list_entry list_entry_t;

struct list_entry {
	void *key;
	void *value;
	list_entry_t *next;
};

typedef struct {
	list_entry_t *list;
	int (*cmp)(const void *, const void *); /* Comparison function */
} list_head_t;


list_head_t *list_init(int (*cmp)(const void *, const void *)){
	//assign cmp
	list_head_t *n;
	n = (list_head_t *) malloc(sizeof(list_head_t));
	if(n == NULL)
	{
		fprintf(stderr, "Error creating list_head_t\n");
		return NULL;
	}
	n->cmp = cmp;
	return n;
};

list_entry_t *list_insert(list_head_t *head, void *key, void *value){
	if(head == NULL)
	{
		fprintf(stderr, "Invalid list_head_t\n");
		return NULL;
	}
	if(key == NULL)
	{
		fprintf(stderr, "Invalid key\n");
		return NULL;
	}

	list_entry_t *new_entry;
	new_entry = (list_entry_t *) malloc(sizeof(list_entry_t));
	new_entry->key = key;
	new_entry->value = value;
	list_entry_t *n;
	n = (list_entry_t *) malloc(sizeof(list_entry_t));

	if(head->list == NULL)
	{//then the list is empty, so add a first entry
		//printf("new");
		head->list = new_entry;
	}
	else
	{
		//printf("adding");
		n = head->list;
		while(n->next != NULL)
			n = n->next;
		n->next = new_entry;
	}
	return new_entry;
};

void *list_search(list_head_t *head, void *key){
	if(head == NULL)
	{
		fprintf(stderr, "Invalid list_head_t\n");
		return NULL;
	}
	if(key == NULL)
	{
		fprintf(stderr, "Invalid key\n");
		return NULL;
	}
	if(head->list == NULL)
	{
		fprintf(stderr, "Search: list is empty!\n");
		return NULL;
	}

	list_entry_t *n;
	n = head->list;
	while(n != NULL)
	{
		if(head->cmp(n->key, key) == 0)
		{
			//printf("found!");
			return n->key;
		}
		else
		{
			//printf("key %s is not %s\n",key, n->key);
			n = n->next;
		}
	}
	return NULL;
};

void list_delete(list_head_t *head){
	assert(head != NULL);
	list_entry_t *temp1;
	temp1 = (list_entry_t *) malloc(sizeof(list_entry_t));
	temp1 = head->list;
	while (temp1 != NULL)
	{
		list_entry_t *temp2; 
		temp2 = (list_entry_t *) malloc(sizeof(list_entry_t));
		temp2 = temp1->next;
		free(temp1);
		temp1 = temp2;
	}
/*
	list_entry_t *o;
	o = (list_entry_t *) malloc(sizeof(list_entry_t));
	list_entry_t *p;
	p = (list_entry_t *) malloc(sizeof(list_entry_t));
	o = head->list;
	free(head);
	while(o != NULL)
	{
		//list_entry_t *p = n->next;
		p = o->next;
		free(o);
		o = p;
	}
	free(p);
*/
	return;
};

int cmp_double(double *a, double *b){
	if(*a == *b)
		return 0;
	else
		return 1;
};

int cmp_string(const void *a, const void *b){
	assert(a != NULL);
	assert(b != NULL);
	return strcmp(a, b);
};