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/****************************************************************************
* net/iob/iob_pack.c
*
* Copyright (C) 2014 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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 <nuttx/config.h>
#if defined(CONFIG_DEBUG) && defined(CONFIG_NET_IOB_DEBUG)
/* Force debug output (from this file only) */
# undef CONFIG_DEBUG_NET
# define CONFIG_DEBUG_NET 1
#endif
#include <string.h>
#include <nuttx/net/iob.h>
#include "iob.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#ifndef MIN
# define MIN(a,b) ((a) < (b) ? (a) : (b))
#endif
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Public Data
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: iob_pack
*
* Description:
* Pack all data in the I/O buffer chain so that the data offset is zero
* and all but the final buffer in the chain are filled. Any emptied
* buffers at the end of the chain are freed.
*
****************************************************************************/
FAR struct iob_s *iob_pack(FAR struct iob_s *iob)
{
FAR struct iob_s *head;
FAR struct iob_s *next;
unsigned int ncopy;
unsigned int navail;
/* Handle special cases */
while (iob->io_len <= 0)
{
iob = iob_free(iob);
}
/* Now remember the head of the chain (for the return value) */
head = iob;
/* Pack each entry in the list */
while (iob)
{
next = iob->io_flink;
/* Eliminate the data offset in this entry */
if (iob->io_offset > 0)
{
memcpy(iob->io_data, &iob->io_data[iob->io_offset], iob->io_len);
iob->io_offset = 0;
}
/* Is there a buffer after this one? */
if (next)
{
/* How many bytes can we copy from the next I/O buffer. Limit the
* size of the copy to the amount of free space in current I/O
* buffer
*/
ncopy = next->io_len;
navail = CONFIG_IOB_BUFSIZE - iob->io_len;
if (ncopy > navail)
{
ncopy = navail;
}
if (ncopy > 0)
{
/* Copy the data from the next into the current I/O buffer iob */
memcpy(&iob->io_data[iob->io_len],
&next->io_data[next->io_offset],
ncopy);
/* Adjust lengths and offsets */
iob->io_len += ncopy;
next->io_len -= ncopy;
next->io_offset += ncopy;
}
/* Have we consumed all of the data in the next entry? */
if (next->io_len <= 0)
{
/* Yes.. free the next entry in I/O buffer chain */
next = iob_free(next);
iob->io_flink = next;
}
}
/* Set up to pack the next entry in the chain */
iob = next;
}
return head;
}
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