/* vim: set ts=4 sw=4 ai:
 * sq.c -- simple queue implementation derived from NetBSD's queue.h
 */

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

struct sqh *sq_new(void)
{
	struct sqh *hd;

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

	return hd;
}

struct sqe *sq_elem_new(void *data)
{
	struct sqe *e;

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

	return e;
}

void sq_insert_head(struct sqh *hd, struct sqe *e)
{
	if ((e->next = hd->first) == NULL)
		hd->last = &e->next;
		
	hd->first = e;
}

void sq_insert_tail(struct sqh *hd, struct sqe *e)
{
	e->next = NULL;
	*hd->last = e;
	hd->last = &e->next;
}

void sq_insert_after(struct sqh *hd, struct sqe *e, struct sqe *n)
{
	if ((n->next = e->next) == NULL)
		hd->last = &n->next;
	e->next = n;
}

void sq_remove_head(struct sqh *hd)
{
	if ((hd->first = hd->first->next) == NULL)
		hd->last = &hd->first;
}

void sq_remove_after(struct sqh *hd, struct sqe *e)
{
	if ((e->next = e->next->next) == NULL)
		hd->last = &e->next;
}

void sq_remove(struct sqh *hd, struct sqe *e)
{
	if (hd->first == e) {
		if ((hd->first = hd->first->next) == NULL)
			hd->last = &hd->first;
	}
	else {
		struct sqe *cur = hd->first;
		while (cur->next != e)
			cur = cur->next;
		if ((cur->next = cur->next->next) == NULL)
			hd->last = &cur->next;
	}
}

void sq_concat(struct sqh *hd1, struct sqh *hd2)
{
	if (!(hd2->first == NULL)) {
		*hd1->last = hd2->first;
		hd1->last = hd2->last;
		hd2->first = NULL;
		hd2->last = &hd2->first;
	}
}

void sq_cleanup(struct sqh *hd, void (*func)(void *))
{
	struct sqe *e, *t;

	sq_foreach_safe(e, hd, t) {
		sq_remove(hd, e);
		if (func)
			func(e->data);
		free(e);
	}
}
struct sqe *sq_find_from_data(struct sqh *hd, const void *data, int (*cmp)(const void *, const void *))
{
	struct sqe *e;

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

	return NULL;
}