android_external_toybox/lib/llist.c
2008-01-20 17:34:53 -06:00

47 lines
1.2 KiB
C

/* 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);
}
}
// 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;
}
// Add an entry to the end off a doubly linked list
void dlist_add(struct double_list **list, char *data)
{
struct double_list *line = xmalloc(sizeof(struct double_list));
line->data = data;
if (*list) {
line->next = *list;
line->prev = (*list)->prev;
(*list)->prev->next = line;
(*list)->prev = line;
} else *list = line->next = line->prev = line;
}