2 * lists.c -- Functions to implement a double linked list XBoard
4 * Copyright 1995,2009 Free Software Foundation, Inc.
6 * ------------------------------------------------------------------------
8 * GNU XBoard is free software: you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation, either version 3 of the License, or (at
11 * your option) any later version.
13 * GNU XBoard is distributed in the hope that it will be useful, but
14 * WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program. If not, see http://www.gnu.org/licenses/. *
21 *------------------------------------------------------------------------
22 ** See the file ChangeLog for a revision history. */
25 * This file could well be a part of backend.c, but I prefer it this
34 #endif /* not STDC_HEADERS */
41 /* Check, if List l is empty; returns TRUE, if it is, FALSE
47 return(l->head == (ListNode *) &l->tail);
51 /* Initialize a list. Must be executed before list is used.
56 l->head = (ListNode *) &l->tail;
58 l->tailPred = (ListNode *) l;
62 /* Remove node n from the list it is inside.
67 if (n->succ != NULL) { /* Be safe */
68 n->pred->succ = n->succ;
69 n->succ->pred = n->pred;
70 n->succ = NULL; /* Mark node as no longer being member */
71 n->pred = NULL; /* of a list. */
88 /* Create a list node with size s. Returns NULL, if out of memory.
90 ListNode *ListNodeCreate(s)
95 if ((n = (ListNode*) malloc(s))) {
96 n->succ = NULL; /* Mark node as not being member of a list. */
103 /* Insert node n into the list of node m after m.
105 void ListInsert(m, n)
115 /* Add node n to the head of list l.
117 void ListAddHead(l, n)
121 ListInsert((ListNode *) &l->head, n);
125 /* Add node n to the tail of list l.
127 void ListAddTail(l, n)
131 ListInsert((ListNode *) l->tailPred, n);
135 /* Return element with number n of list l. (NULL, if n doesn't exist.)
136 * Counting starts with 0.
138 ListNode *ListElem(l, n)
144 for (ln = l->head; ln->succ; ln = ln->succ) {