incubator-nuttx/libs/libc/queue/dq_cat.c

66 lines
2.2 KiB
C

/****************************************************************************
* libs/libc/queue/dq_cat.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <assert.h>
#include <queue.h>
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: dq_cat
*
* Description:
* Move the content of queue1 to the end of queue2.
*
****************************************************************************/
void dq_cat(FAR dq_queue_t *queue1, FAR dq_queue_t *queue2)
{
DEBUGASSERT(queue1 != NULL && queue2 != NULL);
/* If queue2 is empty, then just move queue1 to queue2 */
if (dq_empty(queue2))
{
dq_move(queue1, queue2);
}
/* Do nothing if queue1 is empty */
else if (!dq_empty(queue1))
{
/* Attach the head of queue1 to the final entry of queue2 */
queue2->tail->flink = queue1->head;
queue1->head->blink = queue2->tail;
/* The tail of queue1 is the new tail of queue2 */
queue2->tail = queue1->tail;
dq_init(queue1);
}
}