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/*
*
* Based on fifo.c from syslog-win32 by Alexander Yaworsky
* http://syslog-win32.svn.sourceforge.net/viewvc/syslog-win32/tags/syslog-win32-0-3/daemon/fifo.c
*
* THIS SOFTWARE IS NOT COPYRIGHTED
*
* This source code is offered for use in the public domain. You may
* use, modify or distribute it freely.
*
* This code is distributed in the hope that it will be useful but
* WITHOUT ANY WARRANTY. ALL WARRANTIES, EXPRESS OR IMPLIED ARE HEREBY
* DISCLAIMED. This includes but is not limited to warranties of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*
*/
#include "config.h"
#include <stdlib.h>
#include "fifo.h"
struct fifo_item
{
struct fifo_item *next; /* queue is a single-linked list */
void *payload;
};
struct fifo
{
struct fifo_item *first; /* first pushed item */
struct fifo_item *last; /* last pushed item */
int item_count;
};
/*
* fifo_new:
*
* Allocate and initialize fifo structure. Add an empty item to the fifo.
*/
struct fifo* fifo_new(void)
{
struct fifo *ret = (struct fifo *) malloc(sizeof(struct fifo));
ret->first = NULL;
ret->last = NULL;
ret->item_count = 0;
return ret;
}
/*
* fifo_free:
*
* Delete all items and free fifo structure.
*/
void fifo_free(struct fifo* queue, FifoUserFreeFunction user_free)
{
struct fifo_item *item;
while ((item = queue->first) != NULL)
{
queue->first = item->next;
user_free(item);
}
free(queue);
}
/*
* fifo_push:
*
* Add item to queue.
*/
void fifo_push(struct fifo* queue, void* data)
{
struct fifo_item *item = (struct fifo_item*) malloc(sizeof(struct fifo_item));
item->next = NULL;
item->payload = data;
if (!queue->last)
queue->first = item;
else
queue->last->next = item;
queue->last = item;
}
/*
* fifo_pop:
*
* Extract item from queue. Returns NULL on empty queue.
*/
void* fifo_pop(struct fifo* queue)
{
struct fifo_item *item;
void *data;
item = queue->first;
if (!item)
return NULL;
queue->first = item->next;
if (!queue->first)
queue->last = NULL;
data = item->payload;
free(item);
queue->item_count--;
return data;
}
void* fifo_peek_first(struct fifo *queue) {
return (!queue->first) ? NULL : queue->first->payload;
}
void* fifo_peek_last(struct fifo *queue) {
return (!queue->last) ? NULL : queue->last->payload;
}
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