1  /* SPDX-License-Identifier: LGPL-2.1-or-later */
       2  /*
       3   * This file is part of libmount from util-linux project.
       4   *
       5   * Copyright (C) 2009-2018 Karel Zak <kzak@redhat.com>
       6   *
       7   * libmount is free software; you can redistribute it and/or modify it
       8   * under the terms of the GNU Lesser General Public License as published by
       9   * the Free Software Foundation; either version 2.1 of the License, or
      10   * (at your option) any later version.
      11   */
      12  
      13  /**
      14   * SECTION: iter
      15   * @title: Iterator
      16   * @short_description: unified iterator
      17   *
      18   * The iterator keeps the direction and the last position
      19   * for access to the internal library tables/lists.
      20   */
      21  #include <stdio.h>
      22  #include <string.h>
      23  #include <stdlib.h>
      24  
      25  #include "mountP.h"
      26  
      27  /**
      28   * mnt_new_iter:
      29   * @direction: MNT_INTER_{FOR,BACK}WARD direction
      30   *
      31   * Returns: newly allocated generic libmount iterator.
      32   */
      33  struct libmnt_iter *mnt_new_iter(int direction)
      34  {
      35  	struct libmnt_iter *itr = calloc(1, sizeof(*itr));
      36  	if (!itr)
      37  		return NULL;
      38  	itr->direction = direction;
      39  	return itr;
      40  }
      41  
      42  /**
      43   * mnt_free_iter:
      44   * @itr: iterator pointer
      45   *
      46   * Deallocates the iterator.
      47   */
      48  void mnt_free_iter(struct libmnt_iter *itr)
      49  {
      50  	free(itr);
      51  }
      52  
      53  /**
      54   * mnt_reset_iter:
      55   * @itr: iterator pointer
      56   * @direction: MNT_INTER_{FOR,BACK}WARD or -1 to keep the direction unchanged
      57   *
      58   * Resets the iterator.
      59   */
      60  void mnt_reset_iter(struct libmnt_iter *itr, int direction)
      61  {
      62  	if (direction == -1)
      63  		direction = itr->direction;
      64  
      65  	memset(itr, 0, sizeof(*itr));
      66  	itr->direction = direction;
      67  }
      68  
      69  /**
      70   * mnt_iter_get_direction:
      71   * @itr: iterator pointer
      72   *
      73   * Returns: MNT_INTER_{FOR,BACK}WARD
      74   */
      75  int mnt_iter_get_direction(struct libmnt_iter *itr)
      76  {
      77  	return itr->direction;
      78  }