86 lines
2.8 KiB
C
86 lines
2.8 KiB
C
/****************************************************************************
|
|
* mm/iob/iob_trimhead_queue.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 <nuttx/config.h>
|
|
|
|
#include <assert.h>
|
|
#include <debug.h>
|
|
|
|
#include <nuttx/mm/iob.h>
|
|
|
|
#include "iob.h"
|
|
|
|
#if CONFIG_IOB_NCHAINS > 0
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: iob_trimhead_queue
|
|
*
|
|
* Description:
|
|
* Remove bytes from the beginning of an I/O chain at the head of the
|
|
* queue. Emptied I/O buffers are freed and, hence, the head of the
|
|
* queue may change.
|
|
*
|
|
* This function is just a wrapper around iob_trimhead() that assures that
|
|
* the I/O buffer chain at the head of queue is modified with the trimming
|
|
* operation.
|
|
*
|
|
* Returned Value:
|
|
* The new I/O buffer chain at the head of the queue is returned.
|
|
*
|
|
****************************************************************************/
|
|
|
|
FAR struct iob_s *iob_trimhead_queue(FAR struct iob_queue_s *qhead,
|
|
unsigned int trimlen)
|
|
{
|
|
FAR struct iob_qentry_s *qentry;
|
|
FAR struct iob_s *iob = NULL;
|
|
|
|
/* Peek at the I/O buffer chain container at the head of the queue */
|
|
|
|
qentry = qhead->qh_head;
|
|
if (qentry)
|
|
{
|
|
/* Verify that the queue entry contains an I/O buffer chain */
|
|
|
|
iob = qentry->qe_head;
|
|
if (iob)
|
|
{
|
|
/* Trim the I/Buffer chain and update the queue head */
|
|
|
|
iob = iob_trimhead(iob, trimlen);
|
|
qentry->qe_head = iob;
|
|
}
|
|
}
|
|
|
|
/* Return the new I/O buffer chain at the head of the queue */
|
|
|
|
return iob;
|
|
}
|
|
|
|
#endif /* CONFIG_IOB_NCHAINS > 0 */
|