struct sstack_item *sstack_item_new(void);
struct sstack_item *sstack_item_new_push(unsigned char finished);
struct sstack_item *sstack_item_new_pop(void);
struct sstack_item *sstack_item_new(void);
struct sstack_item *sstack_item_new_push(unsigned char finished);
struct sstack_item *sstack_item_new_pop(void);