#include void init_list(struct dlist_node *n) { n->prev = n; n->next = n; } int list_empty(struct dlist_node *n) { return n->next == n; } void insert_after(struct dlist_node *n, struct dlist_node *to_add) { to_add->next = n->next; to_add->next->prev = to_add; n->next = to_add; to_add->prev = n; } void insert_before(struct dlist_node *n, struct dlist_node *to_add) { to_add->prev = n->prev; to_add->prev->next = to_add; n->prev = to_add; to_add->next = n; } void remove(struct dlist_node *to_remove) { if (!list_empty(to_remove)) { to_remove->next->prev = to_remove->prev; to_remove->prev->next = to_remove->next; init_list(to_remove); } } /* * Remove a series of nodes from a list. Note that this assumes the list is not * empty, and that 'from' comes before 'to' in the list. 'from' and 'to' will * both be removed from the list, along with any nodes which come after 'from' * but before 'to'. */ void remove_splice(struct dlist_node *from, struct dlist_node *to) { to->next->prev = from->prev; from->prev->next = to->next; //make the removed splice become its own wrap-around list, for easy access to the last member when re-splicing to->next = from; from->prev = to; } /* * Add a splice of nodes to a list (most likely a series previously removed via * remove_splice()). */ void insert_splice_before(struct dlist_node *n, struct dlist_node *first, struct dlist_node *last) { first->prev = n->prev; first->prev->next = first; n->prev = last; last->next = n; }