Add floating layer

[wmpus] / util.c

diff --git a/util.c b/util.c
index c5f3b9af021c3351488198be26a5ccbbee8bde20..325c2a2b8ab397dfcd7fd360d3abf0d4a3109d7b 100644 (file)
--- a/util.c
+++ b/util.c
@@ -1,9 +1,27 @@
+/*
+ * Copyright (C) 2011 Andy Spencer <andy753421@gmail.com>
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program 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 General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>
 
 #include "util.h"
 
+/* Doubly linked lists */
 list_t *list_insert(list_t *next, void *data)
 {
        list_t *node = new0(list_t);
@@ -11,14 +29,26 @@ list_t *list_insert(list_t *next, void *data)
        node->next = next;
        node->prev = next ? next->prev : NULL;
        if (node->next) node->next->prev = node;
-       if (node->prev) node->next->next = node;
+       if (node->prev) node->prev->next = node;
        return node;
 }
 
+void list_insert_after(list_t *prev, void *data)
+{
+       // prev must be valid,
+       // as we cannot return the original list head
+       list_t *node = new0(list_t);
+       node->data = data;
+       node->prev = prev;
+       node->next = prev->next;
+       prev->next = node;
+       if (node->next) node->next->prev = node;
+}
+
 list_t *list_append(list_t *head, void *data)
 {
        list_t *last = head;
-       while (last->next)
+       while (last && last->next)
                last = last->next;
        list_t *node = new0(list_t);
        node->data = data;
@@ -45,8 +75,19 @@ int list_length(list_t *node)
        return len;
 }
 
-void list_move(list_t *node, int offset)
+list_t *list_last(list_t *list)
+{
+       while (list && list->next)
+               list = list->next;
+       return list;
+}
+
+list_t *list_find(list_t *list, void *data)
 {
+       for (list_t *cur = list; cur; cur = cur->next)
+               if (cur->data == data)
+                       return cur;
+       return NULL;
 }
 
 /* Misc */