struct node_type {
	int vectorize;
	int flags;

	enum state state;	

	struct list instance;

	size_t size;		
	size_t pool_size;

	struct {
		// Global, per node-type
		int (*start)(struct super_node *sn);
		int (*stop)();
	} type;

	// Function pointers
	void * (*create)();
	int (*init)();
	int (*destroy)(struct node *n);
	int (*parse)(struct node *n, json_t *cfg);
	int (*check)(struct node *n);
	char * (*print)(struct node *n);
	int (*start)(struct node *n);
	int (*stop)(struct node *n);

	int (*read)(struct node *n, struct sample *smps[], 
                    unsigned cnt, unsigned *release);

	int (*write)(struct node *n, struct sample *smps[], 
                     unsigned cnt, unsigned *release);

	int (*reverse)(struct node *n);

	int (*fd)(struct node *n);

	// Memory Type
	struct memory_type * (*memory_type)(struct node *n,
                              struct memory_type *parent);
};