/* * 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" #ifndef lint __unused static const char rcsid[] = "$Sudo: list.c,v 1.6 2008/11/09 14:13:12 millert Exp $"; #endif /* lint */ 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; }