/*
 * hashtable.h
 *
 *  Created on: 21.10.2017
 *      Author: julian
 */

#ifndef HASHTABLE_H_
#define HASHTABLE_H_

#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include "strhash.h"
#include <errno.h>
#include <assert.h>


typedef strhash_t entry_hash_t;
typedef const char * entry_key_t;
typedef struct entry * hashtable_iterator_t;

// data deallocator
typedef void(*hashtable_dealloc)(void*);
// data copy and allocator
typedef void(*hashtable_alloc)(void*);

extern int key_compare(entry_key_t one, entry_key_t two);
extern entry_hash_t key_hash(entry_key_t key);

struct entry {
	entry_hash_t hash;
	entry_key_t key;
	void * data;
};

struct hashtable {
	struct entry * data;
	size_t len, count;

	hashtable_alloc alloc_data;
	hashtable_dealloc dealloc_data;
};

extern hashtable_iterator_t hashtable_end(struct hashtable * table);

/**
 * Iterate of the hashmap.
 *
 * pass the return value to current to iterate over the entire map
 * pass NULL to get the beginning
 *
 * returns the next set entry in the table from current
 * returns hashtable_end() when there is nons
 * example loop:
 * hashmap_iterator_t current = hashtable_next(table, NULL);
 * for(;current != hashtable_end(table); current = hashtable_next(table, current)) {}
 *
 */
hashtable_iterator_t hashtable_next(struct hashtable * table, hashtable_iterator_t current);

/**
 * returns the entry identified by the given hash
 * returns hashtable_end() if no entry matched
 */
hashtable_iterator_t hashtable_get_hash(struct hashtable * table, entry_hash_t hash);

/**
 * returns the entry identified by the given key
 * returns hashtable_end() if no entry matched
 */
hashtable_iterator_t hashtable_get(struct hashtable * table, entry_key_t key);

/**
 * delete all entries of the given table
 *
 * calls dealloc of the table for every data element, if it was set.
 */
void hashtable_clear(struct hashtable * table);

/**
 * insert a new element in the table
 */
int hashtable_add(struct hashtable * table, struct entry entry);

/**
 * resize the hashtable to a new physical size
 * can also try to make the hashtable smaller
 *
 * returns 0 on success
 * returns -1 on error (sets errno)
 * returns -2 if hashtable does not fit in new size.
 */
int hashtable_resize(struct hashtable * table, size_t newsize);

/**
 * add new element in hashtable
 *
 * returns 0 on success
 * returns -1 on error
 */
int hashtable_add(struct hashtable * table, struct entry entry);

/**
 * make a new entry that can be added out of key and data
 */
struct entry hashtable_make_entry(entry_key_t key, void * data);

/**
 * remove one entry using the key
 * @return -1 on error
 * @return 1 on success
 * @return 0 on not found
 */
int hashtable_remove(struct hashtable * table, hashtable_iterator_t it);

#endif /* HASHTABLE_H_ */