2 * lists.c -- Functions to implement a double linked list XBoard
4 * Copyright 1995, 2009, 2010, 2011 Free Software Foundation, Inc.
6 * Enhancements Copyright 2005 Alessandro Scotti
8 * ------------------------------------------------------------------------
10 * GNU XBoard is free software: you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation, either version 3 of the License, or (at
13 * your option) any later version.
15 * GNU XBoard is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program. If not, see http://www.gnu.org/licenses/. *
23 *------------------------------------------------------------------------
24 ** See the file ChangeLog for a revision history. */
27 * This file could well be a part of backend.c, but I prefer it this
36 #endif /* not STDC_HEADERS */
43 /* Check, if List l is empty; returns TRUE, if it is, FALSE
49 return(l->head == (ListNode *) &l->tail);
53 /* Initialize a list. Must be executed before list is used.
58 l->head = (ListNode *) &l->tail;
60 l->tailPred = (ListNode *) l;
64 /* Remove node n from the list it is inside.
69 if (n->succ != NULL) { /* Be safe */
70 n->pred->succ = n->succ;
71 n->succ->pred = n->pred;
72 n->succ = NULL; /* Mark node as no longer being member */
73 n->pred = NULL; /* of a list. */
90 /* Create a list node with size s. Returns NULL, if out of memory.
92 ListNode *ListNodeCreate(s)
97 if ((n = (ListNode*) malloc(s))) {
98 n->succ = NULL; /* Mark node as not being member of a list. */
105 /* Insert node n into the list of node m after m.
107 void ListInsert(m, n)
117 /* Add node n to the head of list l.
119 void ListAddHead(l, n)
123 ListInsert((ListNode *) &l->head, n);
127 /* Add node n to the tail of list l.
129 void ListAddTail(l, n)
133 ListInsert((ListNode *) l->tailPred, n);
137 /* Return element with number n of list l. (NULL, if n doesn't exist.)
138 * Counting starts with 0.
140 ListNode *ListElem(l, n)
146 for (ln = l->head; ln->succ; ln = ln->succ) {