iterator.c
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/* GNU Mailutils -- a suite of utilities for electronic mail
Copyright (C) 1999-2001, 2004-2005, 2007-2008, 2010-2012, 2014-2017
Free Software Foundation, Inc.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 3 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General
Public License along with this library. If not, see
<http://www.gnu.org/licenses/>. */
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <stdlib.h>
#include <string.h>
#include <mailutils/sys/list.h>
#include <mailutils/sys/iterator.h>
#include <mailutils/errno.h>
/* Iterator interface */
struct list_iterator
{
mu_list_t list;
struct list_data *cur;
int backwards; /* true if iterating backwards */
};
static int
first (void *owner)
{
struct list_iterator *itr = owner;
if (itr->backwards)
itr->cur = itr->list->head.prev;
else
itr->cur = itr->list->head.next;
return 0;
}
static int
next (void *owner)
{
struct list_iterator *itr = owner;
if (itr->backwards)
itr->cur = itr->cur->prev;
else
itr->cur = itr->cur->next;
return 0;
}
static int
getitem (void *owner, void **pret, const void **pkey)
{
struct list_iterator *itr = owner;
*pret = itr->cur->item;
if (pkey)
*pkey = NULL;
return 0;
}
static int
finished_p (void *owner)
{
struct list_iterator *itr = owner;
return itr->cur == &itr->list->head;
}
static int
destroy (mu_iterator_t iterator, void *data)
{
struct list_iterator *itr = data;
mu_iterator_detach (&itr->list->itr, iterator);
free (data);
return 0;
}
static int
delitem (void *owner, void *item)
{
struct list_iterator *itr = owner;
return itr->cur == item ? MU_ITR_DELITEM_NEXT : MU_ITR_DELITEM_NOTHING;
}
static int
list_data_dup (void **ptr, void *owner)
{
*ptr = malloc (sizeof (struct list_iterator));
if (*ptr == NULL)
return ENOMEM;
memcpy (*ptr, owner, sizeof (struct list_iterator));
return 0;
}
static int
list_itrctl (void *owner, enum mu_itrctl_req req, void *arg)
{
struct list_iterator *itr = owner;
mu_list_t list = itr->list;
struct list_data *ptr;
switch (req)
{
case mu_itrctl_tell:
/* Return current position in the object */
if (itr->cur == NULL)
return MU_ERR_NOENT;
else
{
size_t count;
for (count = 0, ptr = list->head.next; ptr != &list->head;
ptr = ptr->next, count++)
{
if (ptr == itr->cur)
{
*(size_t*)arg = count;
return 0;
}
}
return MU_ERR_NOENT;
}
break;
case mu_itrctl_delete:
case mu_itrctl_delete_nd:
/* Delete current element */
if (itr->cur == NULL)
return MU_ERR_NOENT;
else
{
struct list_data *prev;
ptr = itr->cur;
prev = ptr->prev;
mu_iterator_delitem (list->itr, ptr);
prev->next = ptr->next;
ptr->next->prev = prev;
if (req == mu_itrctl_delete)
DESTROY_ITEM (list, ptr);
free (ptr);
list->count--;
}
break;
case mu_itrctl_replace:
case mu_itrctl_replace_nd:
/* Replace current element */
if (itr->cur == NULL)
return MU_ERR_NOENT;
if (!arg)
return EINVAL;
ptr = itr->cur;
if (req == mu_itrctl_replace)
DESTROY_ITEM (list, ptr);
ptr = itr->cur;
ptr->item = arg;
break;
case mu_itrctl_insert:
/* Insert new element in the current position */
if (itr->cur == NULL)
return MU_ERR_NOENT;
if (!arg)
return EINVAL;
return _mu_list_insert_item (list, itr->cur, arg, 0);
case mu_itrctl_insert_list:
/* Insert a list of elements */
if (itr->cur == NULL)
return MU_ERR_NOENT;
if (!arg)
return EINVAL;
else
{
mu_list_t new_list = arg;
_mu_list_insert_sublist (list, itr->cur,
new_list->head.next, new_list->head.prev,
new_list->count,
0);
_mu_list_clear (new_list);
}
break;
case mu_itrctl_qry_direction:
if (!arg)
return EINVAL;
else
*(int*)arg = itr->backwards;
break;
case mu_itrctl_set_direction:
if (!arg)
return EINVAL;
else
itr->backwards = !!*(int*)arg;
break;
case mu_itrctl_count:
if (!arg)
return EINVAL;
return mu_list_count (itr->list, arg);
default:
return ENOSYS;
}
return 0;
}
int
mu_list_get_iterator (mu_list_t list, mu_iterator_t *piterator)
{
mu_iterator_t iterator;
int status;
struct list_iterator *itr;
if (!list)
return EINVAL;
itr = calloc (1, sizeof *itr);
if (!itr)
return ENOMEM;
itr->list = list;
itr->cur = NULL;
status = mu_iterator_create (&iterator, itr);
if (status)
{
free (itr);
return status;
}
mu_iterator_set_first (iterator, first);
mu_iterator_set_next (iterator, next);
mu_iterator_set_getitem (iterator, getitem);
mu_iterator_set_finished_p (iterator, finished_p);
mu_iterator_set_delitem (iterator, delitem);
mu_iterator_set_destroy (iterator, destroy);
mu_iterator_set_dup (iterator, list_data_dup);
mu_iterator_set_itrctl (iterator, list_itrctl);
mu_iterator_attach (&list->itr, iterator);
*piterator = iterator;
return 0;
}