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