incubator-nuttx/mm/iob/iob_clone.c

164 lines
4.5 KiB
C

/****************************************************************************
* mm/iob/iob_clone.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 <string.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/mm/iob.h>
#include "iob.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#ifndef MIN
# define MIN(a,b) ((a) < (b) ? (a) : (b))
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: iob_clone
*
* Description:
* Duplicate (and pack) the data in iob1 in iob2. iob2 must be empty.
*
****************************************************************************/
int iob_clone(FAR struct iob_s *iob1, FAR struct iob_s *iob2, bool throttled,
enum iob_user_e consumerid)
{
FAR uint8_t *src;
FAR uint8_t *dest;
unsigned int ncopy;
unsigned int avail1;
unsigned int avail2;
unsigned int offset1;
unsigned int offset2;
DEBUGASSERT(iob2->io_len == 0 && iob2->io_offset == 0 &&
iob2->io_pktlen == 0 && iob2->io_flink == NULL);
/* Copy the total packet size from the I/O buffer at the head of the
* chain.
*/
iob2->io_pktlen = iob1->io_pktlen;
/* Handle special case where there are empty buffers at the head
* the list.
*/
while (iob1->io_len <= 0)
{
iob1 = iob1->io_flink;
}
/* Pack each entry from iob1 to iob2 */
offset1 = 0;
offset2 = 0;
while (iob1)
{
/* Get the source I/O buffer pointer and the number of bytes to copy
* from this address.
*/
src = &iob1->io_data[iob1->io_offset + offset1];
avail1 = iob1->io_len - offset1;
/* Get the destination I/O buffer pointer and the number of bytes to
* copy to that address.
*/
dest = &iob2->io_data[offset2];
avail2 = CONFIG_IOB_BUFSIZE - offset2;
/* Copy the smaller of the two and update the srce and destination
* offsets.
*/
ncopy = MIN(avail1, avail2);
memcpy(dest, src, ncopy);
offset1 += ncopy;
offset2 += ncopy;
/* Have we taken all of the data from the source I/O buffer? */
if (offset1 >= iob1->io_len)
{
/* Skip over empty entries in the chain (there should not be any
* but just to be safe).
*/
do
{
/* Yes.. move to the next source I/O buffer */
iob1 = iob1->io_flink;
}
while (iob1 && iob1->io_len <= 0);
/* Reset the offset to the beginning of the I/O buffer */
offset1 = 0;
}
/* Have we filled the destination I/O buffer? Is there more data to be
* transferred?
*/
if (offset2 >= CONFIG_IOB_BUFSIZE && iob1 != NULL)
{
FAR struct iob_s *next;
/* Allocate new destination I/O buffer and hook it into the
* destination I/O buffer chain.
*/
next = iob_alloc(throttled, consumerid);
if (!next)
{
ioberr("ERROR: Failed to allocate an I/O buffer\n");
return -ENOMEM;
}
iob2->io_flink = next;
iob2 = next;
offset2 = 0;
}
}
return 0;
}