/**************************************************************************** * net/iob/iob_trimhead_queue.c * * Copyright (C) 2014 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3. Neither the name NuttX nor the names of its contributors may be * used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #if defined(CONFIG_DEBUG_FEATURES) && defined(CONFIG_IOB_DEBUG) /* Force debug output (from this file only) */ # undef CONFIG_DEBUG_NET # define CONFIG_DEBUG_NET 1 #endif #include #include #include #include "iob.h" #if CONFIG_IOB_NCHAINS > 0 /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ #ifndef NULL # define NULL ((FAR void *)0) #endif /**************************************************************************** * 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 */