/* vim: set ts=4 sw=4 ai:
 * dl.c -- doubly linked list implementation derived from NetBSD's queue.h
 */

#include <stdlib.h>
#include "dl.h"

struct dlh *dl_new(void)
{
	struct dlh *hd;

	hd = malloc(sizeof(*hd));
	if (hd != NULL)
		dl_init(hd);

	return hd;
}

struct dle *dl_elem_new(void *data)
{
	struct dle *e;

	e = malloc(sizeof(*e));
	if (e != NULL)
		e->data = data;

	return e;
}

void dl_insert_after(struct dle *e, struct dle *n)
{
	if ((n->next = e->next) != NULL)
		 e->next->pprev = &n->next;
	e->next = n;
	n->pprev = &e->next;
}

void dl_insert_before(struct dle *e, struct dle *n)
{
	n->pprev = e->pprev;
	n->next = e;
	*e->pprev = n;
	e->pprev = &n->next;
}

void dl_insert_head(struct dlh *hd, struct dle *e)
{
 	if ((e->next = hd->first) != NULL)
		hd->first->pprev = &e->next;
	hd->first = e;
	e->pprev = &hd->first;
}

void dl_remove(struct dlh *hd, struct dle *e)
{
	if (e->next != NULL)
		e->next->pprev = e->pprev;
	*e->pprev = e->next;
}

void dl_replace(struct dle *e1, struct dle *e2)
{
 	if ((e2->next = e1->next) != NULL)
		e2->next->pprev = &e2->next;
	e2->pprev = e1->pprev;

	*e2->pprev = e2;
}

void dlist_move(struct dlh *hd1, struct dlh *hd2)
{
 	hd2->first = NULL;
	if (!(hd1->first == NULL))
	{
		hd2->first = hd1->first;
		hd2->first->pprev = &hd2->first;
		hd1->first = NULL;
	}
}

void dl_cleanup(struct dlh *hd, void (*func)(void *))
{
	struct dle *e, *t;

	dl_foreach_safe(e, hd, t) {
		dl_remove(hd, e);
		if (func)
			func(e->data);
		free(e);
	}
}

struct dle *dl_find_from_data(struct dlh *hd, const void *data, int (*cmp)(const void *, const void *))
{
	struct dle *e;

	if (hd && !dl_empty(hd))
		dl_foreach(e, hd)
			if (e->data && cmp(e->data, data) == 0)
				return e;

	return NULL;
}