LookingGlass/common/src/ll.c
2023-10-20 15:36:34 +11:00

132 lines
2.5 KiB
C

/**
* Looking Glass
* Copyright © 2017-2023 The Looking Glass Authors
* https://looking-glass.io
*
* This program 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 of the License, or (at your option)
* any later version.
*
* This program 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 this program; if not, write to the Free Software Foundation, Inc., 59
* Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "common/ll.h"
#include "common/debug.h"
#include "common/locking.h"
#include <stdlib.h>
struct ll * ll_new(void)
{
struct ll * list = malloc(sizeof(*list));
if (!list)
{
DEBUG_ERROR("out of memory");
return NULL;
}
list->head = NULL;
list->tail = NULL;
list->count = 0;
LG_LOCK_INIT(list->lock);
return list;
}
void ll_free(struct ll * list)
{
// never free a list with items in it!
DEBUG_ASSERT(!list->head);
LG_LOCK_FREE(list->lock);
free(list);
}
void ll_push(struct ll * list, void * data)
{
struct ll_item * item = malloc(sizeof(*item));
if (!item)
{
DEBUG_ERROR("out of memory");
return;
}
item->data = data;
item->next = NULL;
LG_LOCK(list->lock);
++list->count;
if (!list->head)
{
item->prev = NULL;
list->head = item;
list->tail = item;
LG_UNLOCK(list->lock);
return;
}
item->prev = list->tail;
list->tail->next = item;
list->tail = item;
LG_UNLOCK(list->lock);
}
bool ll_shift(struct ll * list, void ** data)
{
LG_LOCK(list->lock);
if (!list->head)
{
LG_UNLOCK(list->lock);
return false;
}
struct ll_item * item = list->head;
ll_removeNL(list, item);
LG_UNLOCK(list->lock);
if (data)
*data = item->data;
free(item);
return true;
}
bool ll_peek_head(struct ll * list, void ** data)
{
LG_LOCK(list->lock);
if (!list->head)
{
LG_UNLOCK(list->lock);
return false;
}
*data = list->head->data;
LG_UNLOCK(list->lock);
return true;
}
bool ll_peek_tail(struct ll * list, void ** data)
{
LG_LOCK(list->lock);
if (!list->tail)
{
LG_UNLOCK(list->lock);
return false;
}
*data = list->tail->data;
LG_UNLOCK(list->lock);
return true;
}