| /* vi: set sw=4 ts=4 : |
| * llist.c - Linked list functions |
| * |
| * Linked list structures have a next pointer as their first element. |
| */ |
| |
| #include "toys.h" |
| |
| // Free all the elements of a linked list |
| // if freeit!=NULL call freeit() on each element before freeing it. |
| |
| void llist_free(void *list, void (*freeit)(void *data)) |
| { |
| while (list) { |
| void *pop = llist_pop(&list); |
| if (freeit) freeit(pop); |
| else free(pop); |
| |
| // End doubly linked list too. |
| if (list==pop) break; |
| } |
| } |
| |
| // Return the first item from the list, advancing the list (which must be called |
| // as &list) |
| void *llist_pop(void *list) |
| { |
| // I'd use a void ** for the argument, and even accept the typecast in all |
| // callers as documentation you need the &, except the stupid compiler |
| // would then scream about type-punned pointers. Screw it. |
| void **llist = (void **)list; |
| void **next = (void **)*llist; |
| *llist = *next; |
| |
| return (void *)next; |
| } |
| |
| void dlist_add_nomalloc(struct double_list **list, struct double_list *new) |
| { |
| if (*list) { |
| new->next = *list; |
| new->prev = (*list)->prev; |
| (*list)->prev->next = new; |
| (*list)->prev = new; |
| } else *list = new->next = new->prev = new; |
| } |
| |
| |
| // Add an entry to the end of a doubly linked list |
| struct double_list *dlist_add(struct double_list **list, char *data) |
| { |
| struct double_list *new = xmalloc(sizeof(struct double_list)); |
| |
| new->data = data; |
| dlist_add_nomalloc(list, new); |
| |
| return new; |
| } |