intersect.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 <mailutils/sys/list.h>
#include <mailutils/errno.h>
/* Computes an intersection of two lists and returns it in PDEST.
The resulting list contains elements from A that are
also encountered in B (as per comparison function of
the latter).
If DUP_ITEM is not NULL, it is used to create copies of
items to be stored in PDEST. In this case, the destroy_item
function of B is also attached to PDEST. Otherwise, if
DUP_ITEM is NULL, pointers to elements are stored and
no destroy_item function is assigned. */
int
mu_list_intersect_dup (mu_list_t *pdest, mu_list_t a, mu_list_t b,
int (*dup_item) (void **, void *, void *),
void *dup_closure)
{
mu_list_t dest;
int rc;
mu_iterator_t itr;
rc = mu_list_create (&dest);
if (rc)
return rc;
mu_list_set_comparator (dest, b->comp);
if (dup_item)
mu_list_set_destroy_item (dest, b->destroy_item);
rc = mu_list_get_iterator (a, &itr);
if (rc)
{
mu_list_destroy (&dest);
return rc;
}
rc = 0;
for (mu_iterator_first (itr); !mu_iterator_is_done (itr);
mu_iterator_next (itr))
{
void *data;
mu_iterator_current (itr, &data);
if (mu_list_locate (b, data, NULL) == 0)
{
void *new_data;
if (dup_item && data)
{
rc = dup_item (&new_data, data, dup_closure);
if (rc)
break;
}
else
new_data = data;
mu_list_append (dest, new_data); /* FIXME: Check return, and? */
}
}
mu_iterator_destroy (&itr);
*pdest = dest;
return rc;
}
int
mu_list_intersect (mu_list_t *pdest, mu_list_t a, mu_list_t b)
{
return mu_list_intersect_dup (pdest, a, b, NULL, NULL);
}