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diff --git a/src/libdnssec/list/ucw_clists.h b/src/libdnssec/list/ucw_clists.h
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+++ b/src/libdnssec/list/ucw_clists.h
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+/*
+ *	UCW Library -- Circular Linked Lists
+ *
+ *	(c) 2003--2010 Martin Mares <mj@ucw.cz>
+ *
+ *	This software may be freely distributed and used according to the terms
+ *	of the GNU Lesser General Public License.
+ */
+
+#ifndef _UCW_CLISTS_H
+#define _UCW_CLISTS_H
+
+/**
+ * Common header for list nodes.
+ **/
+typedef struct cnode {
+  struct cnode *next, *prev;
+} cnode;
+
+/**
+ * Circular doubly linked list.
+ **/
+typedef struct clist {
+  struct cnode head;
+} clist;
+
+/**
+ * Initialize a new circular linked list. Must be called before any other function.
+ **/
+static inline void clist_init(clist *l)
+{
+  cnode *head = &l->head;
+  head->next = head->prev = head;
+}
+
+/**
+ * Return the first node on \p l or NULL if \p l is empty.
+ **/
+static inline void *clist_head(clist *l)
+{
+  return (l->head.next != &l->head) ? l->head.next : NULL;
+}
+
+/**
+ * Return the last node on \p l or NULL if \p l is empty.
+ **/
+static inline void *clist_tail(clist *l)
+{
+  return (l->head.prev != &l->head) ? l->head.prev : NULL;
+}
+
+/**
+ * Find the next node to \p n or NULL if \p n is the last one.
+ **/
+static inline void *clist_next(clist *l, cnode *n)
+{
+  return (n->next != &l->head) ? (void *) n->next : NULL;
+}
+
+/**
+ * Find the previous node to \p n or NULL if \p n is the first one.
+ **/
+static inline void *clist_prev(clist *l, cnode *n)
+{
+  return (n->prev != &l->head) ? (void *) n->prev : NULL;
+}
+
+/**
+ * Return a non-zero value iff \p l is empty.
+ **/
+static inline int clist_empty(clist *l)
+{
+  return (l->head.next == &l->head);
+}
+
+/**
+ * Loop over all nodes in the \ref list and perform the next C statement on them. The current node is stored in \p n which must be defined before as pointer to any type.
+ * The list should not be changed during this loop command.
+ **/
+#define CLIST_WALK(n,list) for(n=(void*)(list).head.next; (cnode*)(n) != &(list).head; n=(void*)((cnode*)(n))->next)
+
+/**
+ * Same as \ref CLIST_WALK(), but allows removal of the current node. This macro requires one more variable to store some temporary pointers.
+ **/
+#define CLIST_WALK_DELSAFE(n,list,tmp) for(n=(void*)(list).head.next; tmp=(void*)((cnode*)(n))->next, (cnode*)(n) != &(list).head; n=(void*)tmp)
+
+/**
+ * Same as \ref CLIST_WALK(), but it defines the variable for the current node in place. \p type should be a pointer type.
+ **/
+#define CLIST_FOR_EACH(type,n,list) for(type n=(void*)(list).head.next; (cnode*)(n) != &(list).head; n=(void*)((cnode*)(n))->next)
+
+/**
+ * Same as \ref CLIST_WALK_DELSAFE(), but it defines the variable for the current node in place. \p type should be a pointer type. The temporary variable must be still known before.
+ **/
+#define CLIST_FOR_EACH_DELSAFE(type,n,list,tmp) for(type n=(void*)(list).head.next; tmp=(void*)((cnode*)(n))->next, (cnode*)(n) != &(list).head; n=(void*)tmp)
+
+/**
+ * Reversed version of \ref CLIST_FOR_EACH().
+ **/
+#define CLIST_FOR_EACH_BACKWARDS(type,n,list) for(type n=(void*)(list).head.prev; (cnode*)(n) != &(list).head; n=(void*)((cnode*)(n))->prev)
+
+/**
+ * Insert a new node just after the node \p after. To insert at the head of the list, use \ref clist_add_head() instead.
+ **/
+static inline void clist_insert_after(cnode *what, cnode *after)
+{
+  cnode *before = after->next;
+  what->next = before;
+  what->prev = after;
+  before->prev = what;
+  after->next = what;
+}
+
+/**
+ * Insert a new node just before the node \p before. To insert at the tail of the list, use \ref clist_add_tail() instead.
+ **/
+static inline void clist_insert_before(cnode *what, cnode *before)
+{
+  cnode *after = before->prev;
+  what->next = before;
+  what->prev = after;
+  before->prev = what;
+  after->next = what;
+}
+
+/**
+ * Insert a new node in front of all other nodes.
+ **/
+static inline void clist_add_head(clist *l, cnode *n)
+{
+  clist_insert_after(n, &l->head);
+}
+
+/**
+ * Insert a new node after all other nodes.
+ **/
+static inline void clist_add_tail(clist *l, cnode *n)
+{
+  clist_insert_before(n, &l->head);
+}
+
+/**
+ * Remove node \p n.
+ **/
+static inline void clist_remove(cnode *n)
+{
+  cnode *before = n->prev;
+  cnode *after = n->next;
+  before->next = after;
+  after->prev = before;
+}
+
+/**
+ * Remove the first node in \p l, if it exists. Return the pointer to that node or NULL.
+ **/
+static inline void *clist_remove_head(clist *l)
+{
+  cnode *n = clist_head(l);
+  if (n)
+    clist_remove(n);
+  return n;
+}
+
+/**
+ * Remove the last node in \p l, if it exists. Return the pointer to that node or NULL.
+ **/
+static inline void *clist_remove_tail(clist *l)
+{
+  cnode *n = clist_tail(l);
+  if (n)
+    clist_remove(n);
+  return n;
+}
+
+/**
+ * Merge two lists by inserting the list \p what just after the node \p after in a different list.
+ * The first list is then cleared.
+ **/
+static inline void clist_insert_list_after(clist *what, cnode *after)
+{
+  if (!clist_empty(what))
+    {
+      cnode *w = &what->head;
+      w->prev->next = after->next;
+      after->next->prev = w->prev;
+      w->next->prev = after;
+      after->next = w->next;
+      clist_init(what);
+    }
+}
+
+/**
+ * Move all items from a source list to a destination list. The source list
+ * becomes empty, the original contents of the destination list are destroyed.
+ **/
+static inline void clist_move(clist *to, clist *from)
+{
+  clist_init(to);
+  clist_insert_list_after(from, &to->head);
+  clist_init(from);
+}
+
+/**
+ * Compute the number of nodes in \p l. Beware of linear time complexity.
+ **/
+static inline unsigned int clist_size(clist *l)
+{
+  unsigned int i = 0;
+  CLIST_FOR_EACH(cnode *, n, *l)
+    i++;
+  return i;
+}
+
+/**
+ * Remove a node \p n and mark it as unlinked by setting the previous and next pointers to NULL.
+ **/
+static inline void clist_unlink(cnode *n)
+{
+  clist_remove(n);
+  n->prev = n->next = NULL;
+}
+
+/**
+ * Remove the first node on \p l and mark it as unlinked.
+ * Return the pointer to that node or NULL.
+ **/
+static inline void *clist_unlink_head(clist *l)
+{
+  cnode *n = clist_head(l);
+  if (n)
+    clist_unlink(n);
+  return n;
+}
+
+/**
+ * Remove the last node on \p l and mark it as unlinked.
+ * Return the pointer to that node or NULL.
+ **/
+static inline void *clist_unlink_tail(clist *l)
+{
+  cnode *n = clist_tail(l);
+  if (n)
+    clist_unlink(n);
+  return n;
+}
+
+/**
+ * Check if a node is linked a list. Unlinked nodes are recognized by having their
+ * previous and next pointers equal to NULL. Returns 0 or 1.
+ *
+ * Nodes initialized to all zeroes are unlinked, inserting a node anywhere in a list
+ * makes it linked. Normal removal functions like \ref clist_remove() do not mark nodes
+ * as unlinked, you need to call \ref clist_unlink() instead.
+ **/
+static inline int clist_is_linked(cnode *n)
+{
+  return !!n->next;
+}
+
+#endif