px4-firmware/nuttx/libc/dirent/lib_telldir.c

/****************************************************************************
 * libc/dirent/fs_telldir.c
 *
 *   Copyright (C) 2007-2008, 2011-2012 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>

#include <sys/types.h>
#include <dirent.h>
#include <errno.h>

#include <nuttx/fs/fs.h>
#include <nuttx/fs/dirent.h>

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: telldir
 *
 * Description:
 *   The telldir() function returns the current location
 *   associated with the directory stream dirp.
 *
 * Inputs:
 *   dirp -- An instance of type DIR created by a previous
 *     call to opendir();
 *
 * Return:
 *   On success, the telldir() function returns the current
 *   location in the directory stream.  On error, -1 is
 *   returned, and errno is set appropriately.
 *
 *   EBADF - Invalid directory stream descriptor dir
 *
 ****************************************************************************/

off_t telldir(FAR DIR *dirp)
{
  struct fs_dirent_s *idir = (struct fs_dirent_s *)dirp;

  if (!idir || !idir->fd_root)
    {
      set_errno(EBADF);
      return (off_t)-1;
    }

  /* Just return the current position */

  return idir->fd_position;
}