/*
 * Tiny doubly-linked list implementation.
 * Copyright (c) 2023-2024, Quinn Stephens and the OSMORA team.
 * Provided under the BSD 3-Clause license.
 */

#ifndef _LIST_H
#define _LIST_H

#include <stddef.h>

struct list_entry {
    struct list_entry *prev;
    struct list_entry *next;
};

struct list {
    struct list_entry *tail;
    struct list_entry *head;
    size_t length;
};

static inline void
list_remove(struct list_entry *entry)
{
    entry->prev->next = entry->next;
    entry->next->prev = entry->prev;
}

static inline void
list_append(struct list *list, struct list_entry *entry)
{
    entry->prev = list->tail;
    entry->next = (struct list_entry*)list;
    entry->prev->next = entry;
    list->tail = entry;
    list->length++;
}

static inline void
list_prepend(struct list *list, struct list_entry *entry)
{
    entry->next = list->head;
    entry->prev = (struct list_entry*)list;
    entry->next->prev = entry;
    list->head = entry;
    list->length++;
}

static inline void
list_init(struct list *list)
{
    list->tail = (struct list_entry*)list;
    list->head = (struct list_entry*)list;
    list->length = 0;
}

#endif /* !_LIST_H */