84 lines
2.4 KiB
C
84 lines
2.4 KiB
C
/****************************************************************************
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* mm/iob/iob_reserve.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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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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#include <nuttx/mm/iob.h>
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#include "iob.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: iob_reserve
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*
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* Description:
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* Adjust headroom offset of iobs by reducing the tail room.
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*
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****************************************************************************/
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void iob_reserve(FAR struct iob_s *iob, unsigned int reserved)
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{
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unsigned int offset;
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/* Empty iob buffer is allowed, update packet length. */
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if (iob->io_pktlen > reserved)
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{
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iob->io_pktlen -= reserved;
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}
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else
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{
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iob->io_pktlen = 0;
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}
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/* Update offset and reducing the tail room */
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while (iob != NULL && reserved > 0)
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{
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if (reserved > CONFIG_IOB_BUFSIZE)
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{
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offset = CONFIG_IOB_BUFSIZE;
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}
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else
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{
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offset = reserved;
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}
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if (iob->io_len > offset)
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{
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iob->io_len -= offset;
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}
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else
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{
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iob->io_len = 0;
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}
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iob->io_offset = offset;
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iob = iob->io_flink;
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reserved -= offset;
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}
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}
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