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/*
Copyright (C) 2009 Free Software Foundation, Inc.
Written by Zheng Da.
This file is part of the GNU Hurd.
The GNU Hurd is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
The GNU Hurd 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with the GNU Hurd; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
/* This file implements a double linked list. */
#include "list.h"
void entry_init (struct list *entry)
{
entry->next = entry;
entry->prev = entry;
}
void add_entry_head (struct list *head, struct list *entry)
{
entry->next = head->next;
head->next->prev = entry;
head->next = entry;
entry->prev = head;
}
void add_entry_end (struct list *head, struct list *entry)
{
entry->next = head;
entry->prev = head->prev;
head->prev->next = entry;
head->prev = entry;
}
struct list *remove_entry_head (struct list *head)
{
struct list *entry = head->next;
if (EMPTY_LIST (entry))
return NULL;
remove_entry (entry);
return entry;
}
struct list *remove_entry_end (struct list *head)
{
struct list *entry = head->prev;
if (EMPTY_LIST (entry))
return NULL;
remove_entry (entry);
return entry;
}
void remove_entry (struct list *entry)
{
entry->next->prev = entry->prev;
entry->prev->next = entry->next;
}
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