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/projects/cubeos/src_current/kernel/list.c

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/*  src/kernel/list.c
   CubeOS Version 0.4.90
   Copyright (C) 1999,2000 Holger Kenn

   CubeOS is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or any later version.

   CubeOS is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.

 */
#include <stddef.h>
#include <list.h>
entry *
  LIST_head (list * l)
{
        if (l == NULL)
                return NULL;
        return l->head;
}

entry *
  LIST_tail (list * l)
{
        if (l == NULL)
                return NULL;
        return l->tail;
}

void LIST_init (list * l)
{
        if (l == NULL)
                return;
        l->head = NULL;
        l->tail = NULL;
        l->entries = 0;
        l->type = LIST_TYPE_USER;
}

int LIST_entries (list * l)
{
        if (l == NULL)
                return -1;
        return l->entries;
}

void LIST_insert_after (entry * e, entry * x)
{
        if (e == NULL)
                return;
        if (e->list)
                return;
        if (x == NULL)
                return;
        if (x->list == NULL)
                return;
        e->prev = x;
        e->next = x->next;
        x->next = e;
        if (x->list->tail == x)
                x->list->tail = e;
        e->list = x->list;
        e->list->entries++;
}


void LIST_insert_before (entry * e, entry * x)
{
        if (e == NULL)
                return;
        if (e->list)
                return;
        if (x == NULL)
                return;
        if (x->list == NULL)
                return;
        e->prev = x->prev;
        e->next = x;
        x->prev = e;
        if (x->list->head == x)
                x->list->head = e;
        e->list = x->list;
        e->list->entries++;
}


void LIST_insert_head (list * l, entry * e)
{
        if (l == NULL)
                return;
        if (e == NULL)
                return;
        if (e->list)
                return;
        if (l->head == NULL) {
                l->head = e;
                l->tail = e;
                e->prev = NULL;
                e->next = NULL;
                e->list = l;
                l->entries++;
        } else
                LIST_insert_before (e, l->head);
}

void LIST_insert_tail (list * l, entry * e)
{
        if (l == NULL)
                return;
        if (e == NULL)
                return;
        if (e->list)
                return;
        if (l->tail == NULL) {
                l->head = e;
                l->tail = e;
                e->prev = NULL;
                e->next = NULL;
                e->list = l;
                l->entries++;
        } else
                LIST_insert_after (e, l->tail);
}

void LIST_delete (entry * e)
{
        if (e == NULL)
                return;
        if (e->list == NULL)
                return;
        if (e->prev)
                e->prev->next = e->next;
        if (e->next)
                e->next->prev = e->prev;
        if (e == e->list->tail)
                e->list->tail = e->prev;
        if (e == e->list->head)
                e->list->head = e->next;
        e->list->entries--;
        e->list = NULL;
}

void LIST_makeentry (entry * e)
{
        if (e == NULL)
                return;
        e->list = NULL;
        e->prev = NULL;
        e->next = NULL;
        e->data = NULL;
        e->len = 0;
}

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