blob: 60c1138026ac7ad0c84858cbd4ad959820abc385 [file] [log] [blame]
/*
* Copyright (c) 2007-2008 Todd C. Miller <Todd.Miller@courtesan.com>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <config.h>
#include <sys/types.h>
#include <stdio.h>
#ifdef STDC_HEADERS
# include <stdlib.h>
# include <stddef.h>
#else
# ifdef HAVE_STDLIB_H
# include <stdlib.h>
# endif
#endif /* STDC_HEADERS */
#include "sudo.h"
struct list_proto {
struct list_proto *prev;
struct list_proto *next;
};
struct list_head_proto {
struct list_proto *first;
struct list_proto *last;
};
/*
* Pop the last element off the end of vh.
* Returns the popped element.
*/
void *
tq_pop(vh)
void *vh;
{
struct list_head_proto *h = (struct list_head_proto *)vh;
void *last = NULL;
if (!tq_empty(h)) {
last = (void *)h->last;
if (h->first == h->last) {
h->first = NULL;
h->last = NULL;
} else {
h->last = h->last->prev;
h->last->next = NULL;
}
}
return (last);
}
/*
* Convert from a semi-circle queue to normal doubly-linked list
* with a head node.
*/
void
list2tq(vh, vl)
void *vh;
void *vl;
{
struct list_head_proto *h = (struct list_head_proto *)vh;
struct list_proto *l = (struct list_proto *)vl;
if (l != NULL) {
#ifdef DEBUG
if (l->prev == NULL) {
warningx("list2tq called with non-semicircular list");
abort();
}
#endif
h->first = l;
h->last = l->prev; /* l->prev points to the last member of l */
l->prev = NULL; /* zero last ptr now that we have a head */
} else {
h->first = NULL;
h->last = NULL;
}
}
/*
* Append one queue (or single entry) to another using the
* circular properties of the prev pointer to simplify the logic.
*/
void
list_append(vl1, vl2)
void *vl1;
void *vl2;
{
struct list_proto *l1 = (struct list_proto *)vl1;
struct list_proto *l2 = (struct list_proto *)vl2;
void *tail = l2->prev;
l1->prev->next = l2;
l2->prev = l1->prev;
l1->prev = tail;
}
/*
* Append the list of entries to the head node and convert
* e from a semi-circle queue to normal doubly-linked list.
*/
void
tq_append(vh, vl)
void *vh;
void *vl;
{
struct list_head_proto *h = (struct list_head_proto *)vh;
struct list_proto *l = (struct list_proto *)vl;
void *tail = l->prev;
if (h->first == NULL)
h->first = l;
else
h->last->next = l;
l->prev = h->last;
h->last = tail;
}