+#include <stdio.h>
+#include <stdlib.h>
+
+#include "util.h"
+
+list_t *list_insert(list_t *next, void *data)
+{
+ list_t *node = new0(list_t);
+ node->data = data;
+ node->next = next;
+ node->prev = next ? next->prev : NULL;
+ if (node->next) node->next->prev = node;
+ if (node->prev) node->next->next = node;
+ return node;
+}
+
+list_t *list_remove(list_t *head, list_t *node)
+{
+ list_t *next = node->next;
+ list_t *prev = node->prev;
+ if (next) next->prev = prev;
+ if (prev) prev->next = next;
+ free(node);
+ return head == node ? next : head;
+}
+
+int list_length(list_t *node)
+{
+ int len = 0;
+ for (; node; node = node->next)
+ len++;
+ return len;
+}
+
+void list_move(list_t *node, int offset)
+{
+}