103 lines
3.6 KiB
C
103 lines
3.6 KiB
C
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/****************************************************************************
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* net/iob/iob_peek_queue.c
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*
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* Copyright (C) 2014 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#if defined(CONFIG_DEBUG) && defined(CONFIG_IOB_DEBUG)
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/* Force debug output (from this file only) */
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# undef CONFIG_DEBUG_NET
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# define CONFIG_DEBUG_NET 1
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#endif
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#include <debug.h>
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#include <nuttx/net/iob.h>
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#include "iob.h"
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#if CONFIG_IOB_NCHAINS > 0
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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#ifndef NULL
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# define NULL ((FAR void *)0)
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#endif
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: iob_peek_queue
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*
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* Description:
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* Return a reference to the I/O buffer chain at the head of a queue. This
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* is similar to iob_remove_queue except that the I/O buffer chain is in
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* place at the head of the queue. The I/O buffer chain may safely be
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* modified by the caller but must be removed from the queue before it can
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* be freed.
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*
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* Returned Value:
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* Returns a reference to the I/O buffer chain at the head of the queue.
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*
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****************************************************************************/
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FAR struct iob_s *iob_peek_queue(FAR struct iob_queue_s *iobq)
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{
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FAR struct iob_qentry_s *qentry;
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FAR struct iob_s *iob = NULL;
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/* Peek at the I/O buffer chain container at the head of the queue */
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qentry = iobq->qh_head;
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if (qentry)
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{
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/* Return the I/O buffer chain from the container */
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iob = qentry->qe_head;
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}
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return iob;
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}
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#endif /* CONFIG_IOB_NCHAINS > 0 */
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