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/************************************************************
* fs_seekdir.c
*
* Copyright (C) 2007 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* 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 Gregory Nutt 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>
#include <sys/types.h>
#include <dirent.h>
#include <errno.h>
#include <nuttx/fs.h>
#include "fs_internal.h"
/************************************************************
* Private Functions
************************************************************/
/************************************************************
* Public Functions
************************************************************/
/************************************************************
* Name: seekdir
*
* Description:
* The seekdir() function sets the location in the
* directory stream from which the next readdir() call will
* start. seekdir() should be used with an offset returned
* by telldir().
*
* Inputs:
* dirp -- An instance of type DIR created by a previous
* call to opendir();
* offset -- offset to seek to
*
* Return:
* None
*
************************************************************/
#if CONFIG_NFILE_DESCRIPTORS > 0
void seekdir(FAR DIR *dirp, off_t offset)
{
struct internal_dir_s *idir = (struct internal_dir_s *)dirp;
struct inode *curr;
struct inode *prev;
off_t i;
if (idir)
{
/* Traverse the peer list starting at the 'root' of the
* the list until we find the node at 'offset". If devices
* are being registered and unregistered, then this can
* be a very unpredictable operation.
*/
inode_semtake();
for (i = 0, curr = idir->root;
curr && i != offset;
i++, curr = curr->i_peer);
/* Now get the inode to vist next time that readdir() is called */
prev = idir->next;
idir->next = curr; /* The next node to visit */
if (curr)
{
/* Increment the reference count on this next node */
curr->i_crefs++;
}
inode_semgive();
if (prev)
{
inode_release(prev);
}
}
}
#endif /* CONFIG_NFILE_DESCRIPTORS */
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