libfdisk/src/iter.c

   1 /*
   2  * Copyright (C) 2009 Karel Zak <kzak@redhat.com>
   3  *
   4  * This file may be redistributed under the terms of the
   5  * GNU Lesser General Public License.
   6  */
   7
   8 /**
   9  * SECTION: iter
  10  * @title: Iterator
  11  * @short_description: unified iterator
  12  *
  13  * The iterator keeps the direction and the last position for access to the
  14  * internal library tables/lists.
  15  *
  16  * It's very unusual to use the same iterator on multiple places in your
  17  * application or share the same iterator, for this purpose libfdisk does not
  18  * provide reference counting for this object. It's recommended to initialize
  19  * the iterator by fdisk_new_iter() at begin of your function and then
  20  * fdisk_free_iter() before you return from the function.
  21  *
  22  * Don't forget to call fdisk_reset_iter() if you want to use the iterator more
  23  * than once.
  24  */
  25 #include <stdio.h>
  26 #include <string.h>
  27 #include <stdlib.h>
  28
  29 #include "fdiskP.h"
  30
  31 /**
  32  * fdisk_new_iter:
  33  * @direction: FDISK_INTER_{FOR,BACK}WARD direction
  34  *
  35  * Returns: newly allocated generic libmount iterator.
  36  */
  37 struct fdisk_iter *fdisk_new_iter(int direction)
  38 {
  39         struct fdisk_iter *itr = calloc(1, sizeof(*itr));
  40         if (!itr)
  41                 return NULL;
  42         itr->direction = direction;
  43         return itr;
  44 }
  45
  46 /**
  47  * fdisk_free_iter:
  48  * @itr: iterator pointer
  49  *
  50  * Deallocates the iterator.
  51  */
  52 void fdisk_free_iter(struct fdisk_iter *itr)
  53 {
  54         free(itr);
  55 }
  56
  57 /**
  58  * fdisk_reset_iter:
  59  * @itr: iterator pointer
  60  * @direction: FDISK_ITER_{FOR,BACK}WARD or -1 to keep the direction unchanged
  61  *
  62  * Resets the iterator.
  63  */
  64 void fdisk_reset_iter(struct fdisk_iter *itr, int direction)
  65 {
  66         if (direction == -1)
  67                 direction = itr->direction;
  68
  69         memset(itr, 0, sizeof(*itr));
  70         itr->direction = direction;
  71 }
  72
  73 /**
  74  * fdisk_iter_get_direction:
  75  * @itr: iterator pointer
  76  *
  77  * Returns: FDISK_INTER_{FOR,BACK}WARD
  78  */
  79 int fdisk_iter_get_direction(struct fdisk_iter *itr)
  80 {
  81         return itr->direction;
  82 }