used like:
	node = db->ht[db->hash(key, db->maxlen)%HASH_SIZE];
	while (node) {
		c = db->cmp(key, node->key, db->maxlen);
		if (c == 0) {
			if (!(node->deleted)) {
				db->cache = node;
				found = true;
			}
			break;
		}
		if (c < 0)
			node = node->left;
		else
			node = node->right;
	}
---

/**
 * Default hasher for DB_INT databases.
 * Returns the value of the key as an unsigned int.
 * <code>maxlen</code> is ignored.
 * @param key Key to be hashed
 * @param maxlen Maximum length of the key to hash
 * @return hash of the key
 * @see DBType#DB_INT
 * @see #DBHasher
 * @see #db_default_hash(DBType)
 */
static unsigned int db_int_hash(DBKey key, unsigned short maxlen)
{
	(void)maxlen;//not used
	DB_COUNTSTAT(db_int_hash);
	return (unsigned int)key.i;
}

/**
 * Default hasher for DB_UINT databases.
 * Just returns the value of the key.
 * <code>maxlen</code> is ignored.
 * @param key Key to be hashed
 * @param maxlen Maximum length of the key to hash
 * @return hash of the key
 * @see DBType#DB_UINT
 * @see #DBHasher
 * @see #db_default_hash(DBType)
 */
static unsigned int db_uint_hash(DBKey key, unsigned short maxlen)
{
	(void)maxlen;//not used
	DB_COUNTSTAT(db_uint_hash);
	return key.ui;
}

/**
 * Default hasher for DB_STRING databases.
 * @param key Key to be hashed
 * @param maxlen Maximum length of the key to hash
 * @return hash of the key
 * @see DBType#DB_STRING
 * @see #DBHasher
 * @see #db_default_hash(DBType)
 */
static unsigned int db_string_hash(DBKey key, unsigned short maxlen)
{
	const char *k = key.str;
	unsigned int hash = 0;
	unsigned short i;

	DB_COUNTSTAT(db_string_hash);

	for (i = 0; *k; ++i) {
		hash = (hash*33 + ((unsigned char)*k))^(hash>>24);
		k++;
		if (i == maxlen)
			break;
	}

	return hash;
}

/**
 * Default hasher for DB_ISTRING databases.
 * @param key Key to be hashed
 * @param maxlen Maximum length of the key to hash
 * @return hash of the key
 * @see DBType#DB_ISTRING
 * @see #db_default_hash(DBType)
 */
static unsigned int db_istring_hash(DBKey key, unsigned short maxlen)
{
	const char *k = key.str;
	unsigned int hash = 0;
	unsigned short i;

	DB_COUNTSTAT(db_istring_hash);

	for (i = 0; *k; i++) {
		hash = (hash*33 + ((unsigned char)TOLOWER(*k)))^(hash>>24);
		k++;
		if (i == maxlen)
			break;
	}

	return hash;
}

/**
 * Default hasher for DB_INT64 databases.
 * Returns the value of the key as an unsigned int.
 * <code>maxlen</code> is ignored.
 * @param key Key to be hashed
 * @param maxlen Maximum length of the key to hash
 * @return hash of the key
 * @see DBType#DB_INT64
 * @see #DBHasher
 * @see #db_default_hash(DBType)
 */
static unsigned int db_int64_hash(DBKey key, unsigned short maxlen)
{
	(void)maxlen;//not used
	DB_COUNTSTAT(db_int64_hash);
	return (unsigned int)key.i64;
}

/**
 * Default hasher for DB_UINT64 databases.
 * Just returns the value of the key.
 * <code>maxlen</code> is ignored.
 * @param key Key to be hashed
 * @param maxlen Maximum length of the key to hash
 * @return hash of the key
 * @see DBType#DB_UINT64
 * @see #DBHasher
 * @see #db_default_hash(DBType)
 */
static unsigned int db_uint64_hash(DBKey key, unsigned short maxlen)
{
	(void)maxlen;//not used
	DB_COUNTSTAT(db_uint64_hash);
	return (unsigned int)key.ui64;
}