From fde810862b488812beb635c6e95add7d254e615c Mon Sep 17 00:00:00 2001 From: Gregory Nutt Date: Sat, 7 Jun 2014 11:01:13 -0600 Subject: IOB: Add iob_contig() --- nuttx/net/iob/Make.defs | 5 +- nuttx/net/iob/iob_contig.c | 172 +++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 173 insertions(+), 4 deletions(-) create mode 100755 nuttx/net/iob/iob_contig.c (limited to 'nuttx/net') diff --git a/nuttx/net/iob/Make.defs b/nuttx/net/iob/Make.defs index 9ad9b871b..e522d5885 100644 --- a/nuttx/net/iob/Make.defs +++ b/nuttx/net/iob/Make.defs @@ -33,15 +33,12 @@ # ############################################################################ -NET_ASRCS = -NET_CSRCS = - ifeq ($(CONFIG_NET_IOB),y) # Include IOB src files NET_CSRCS += iob_add_queue.c iob_alloc.c iob_alloc_qentry.c iob_clone.c -NET_CSRCS += iob_concat.c iob_copyin.c iob_copyout.c iob_free.c +NET_CSRCS += iob_concat.c iob_copyin.c iob_copyout.c iob_contig.c iob_free.c NET_CSRCS += iob_free_chain.c iob_free_qentry.c iob_free_queue.c NET_CSRCS += iob_initialize.c iob_pack.c iob_remove_queue.c iob_trimhead.c NET_CSRCS += iob_trimtail.c diff --git a/nuttx/net/iob/iob_contig.c b/nuttx/net/iob/iob_contig.c new file mode 100755 index 000000000..fd312dfbd --- /dev/null +++ b/nuttx/net/iob/iob_contig.c @@ -0,0 +1,172 @@ +/**************************************************************************** + * net/iob/iob_contig.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 + +#include +#include +#include +#include + +#include + +#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_contig + * + * Description: + * Ensure that there is'len' bytes of contiguous space at the beginning + * of the I/O buffer chain starting at 'iob'. + * + ****************************************************************************/ + +int iob_contig(FAR struct iob_s *iob, unsigned int len) +{ + FAR struct iob_s *next; + unsigned int ncopy; + + /* We can't make more contiguous space that the size of one I/O buffer. + * If you get this assertion and really need that much contiguous data, + * then you will need to increase CONFIG_IOB_BUFSIZE. + */ + + DEBUGASSERT(len <= CONFIG_IOB_BUFSIZE); + + /* Check if there is already sufficient, contiguous space at the beginning + * of the packet + */ + + if (len <= iob->io_len) + { + /* Yes we are good */ + + return 0; + } + + /* Can we get the required amount of contiguous data by just packing the + * head I/0 buffer? + */ + + else if (len <= iob->io_pktlen) + { + /* Yes.. First eliminate any leading offset */ + + if (iob->io_offset > 0) + { + memcpy(iob->io_data, &iob->io_data[iob->io_offset], iob->io_len); + iob->io_offset = 0; + } + + /* Then move what we need from the next I/O buffer(s) */ + + do + { + /* Get the next I/O buffer in the chain */ + + next = iob->io_flink; + DEBUGASSERT(next != NULL && next->io_len > 0); + + /* Copy what we need or what we can from the next buffer */ + + ncopy = len - iob->io_len; + ncopy = MIN(ncopy, next->io_len); + memcpy(&iob->io_data[iob->io_len], + &next->io_data[next->io_offset], ncopy); + + /* Adjust counts and offsets */ + + iob->io_len += ncopy; + next->io_offset += ncopy; + next->io_len -= ncopy; + + /* Handle a (improbable) case where we just emptied the second + * buffer in the chain. + */ + + if (next->io_len == 0) + { + iob->io_flink = iob_free(next); + } + } + while (len > iob->io_len); + + /* This should always succeed because we know that: + * + * pktlen >= CONFIG_IOB_BUFSIZE >= len + */ + + return 0; + } + + /* Otherwise, the request for contiguous data is larger then the entire + * packet. We can't do that without extending the I/O buffer chain with + * garbage (which would probably not be what the caller wants). + */ + + else + { + ndbg("ERROR: pktlen=%u < requested len=%u\n", iob->io_pktlen, len); + return -ENOSPC; + } +} -- cgit v1.2.3