/*
 * Copyright 2004-2008, François Revol, <revol@free.fr>.
 * Distributed under the terms of the MIT License.
 */

#include <OS.h>
#include "lists.h"

void slist_init(struct _slist_entry *item)
{
        item->next = NULL;
}

void slist_uninit(struct _slist_entry *item)
{
        item->next = NULL;
}

struct _slist_entry *slist_find(struct _slist_entry *head, slist_compare_func func, void *id)
{
        struct _slist_entry *p = head;
        if (head == NULL)
                return NULL;
        while (p) {
                if (func(p, id) == 0)
                        return p;
                p = p->next;
        }
        return NULL;
}

status_t slist_insert_head(struct _slist_entry **head, struct _slist_entry *item)
{
        struct _slist_entry *next = NULL;
        if (head == NULL || item == NULL)
                return EINVAL;
        if (*head)
                next = *head;
        item->next = next;
        *head = item;
        return B_OK;
}

struct _slist_entry *slist_dequeue_tail(struct _slist_entry **head)
{
        struct _slist_entry **prev = NULL;
        struct _slist_entry *curr = NULL;
        if (head == NULL || *head == NULL)
                return NULL;
        prev = head;
        curr = *head;
        while (curr->next) {
                prev = &(curr->next);
                curr = curr->next;
        }
        *prev = NULL;
        return curr;
}

status_t slist_remove(struct _slist_entry **head, struct _slist_entry *item)
{
        struct _slist_entry **prev = NULL;
        struct _slist_entry *curr = NULL;
        if (head == NULL || *head == NULL || item == NULL)
                return EINVAL;
        prev = head;
        curr = *head;
        while (prev && curr) {
                if (curr == item) {
                        *prev = curr->next;
                        curr->next = NULL;
                        return B_OK;
                }
                prev = &(curr->next);
                curr = curr->next;
        }
        return ENOENT;
}

struct _slist_entry *slist_next(struct _slist_entry *item)
{
        if (!item || !item->next)
                return NULL;
        return item->next;
}